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[Question] [ Related to [How far in the past could unprepared humans survive?](https://worldbuilding.stackexchange.com/q/57120/20149), but assumes a single survivalist, purpose-trained for his mission. He is to time travel as far back as he can and attempt to survive for an entire year. He is to be presented with extensive information about his chosen time period and has as much training as he'd like, although he's the first time traveler, so the training is limited by modern paleontology. To travel time, he must provide the machine with geographical coordinates as well as a period of time in Mya (million years ago). The machine will place him at ground level at the nearest land to his specified coordinates, so he won't have to worry that he'll be placed in the middle of the ocean if our estimates of ancient geography are off. Unfortunately, he cannot bring anything with him. How far back could he go? If he goes far enough back, he won't have to worry about predators, but if he goes too far back, everything will be too deep underwater, or there may not be enough oxygen. His immune system will be more than capable of adapting to ancient microbes that are hundreds of millions of years behind in the pathological arms race, so it's likely that he would not even need to purify water if he's as early as the Paleozoic. [Answer] ### My vote: 145 million years ago. Because fruit. There are a lot of nutrients that we can't do without. The most prominent example is vitamin C, which is hard to find without fruit. Fruit didn't really exist until the Cretaceous Period. Prior to that, animals needed digestive systems that could wrench those nutrients out of less compact sources. This is a less hard-core limit than oxygen, and could be hand-waved away for most audiences, but it provides another rational point of "earliest" that could be used. Update: If you presume that all animals are basically deer with a slightly different body shape, you could find pituitary glands as early as 400m BCE to get Vitamin C from. That's a bit of a stretch, but again, no fossil evidence of soft tissues, so check the warranty on your artistic license. Prior to that, land creatures were basically mites, centipedes, and spiders. You didn't even get the monster eight-foot-long N-ipedes until around 360m BCE. They might have been person-sized, but their entire gland structure is different. Further update: When the OP said "highly trained survivalist," I'm presuming that whoever sent the survivalist back in time had the opportunity to sample the prehistoric food and figure out which plants and animals had nutritional value. From there, I'm taking a SWAG at whether the nutrients could be extracted from the food in adequate quantities by picking and choosing what they eat. I feel comfortable saying that sending a person back even 50 million years with no knowledge of which foods are edible would guarantee death. That might make a good, if less focused, follow-up question. It's not that the nutrition isn't available, it's that it would be hard to recognize. I wouldn't think that the equivalent of a pituitary gland would be identifiable without a lot of specimens and lab time. Remember that this is a survivalist, not a paleontologist. [Answer] ## As far back as the oxygen content allows The limit seems to be 500 Mya. [![O2/time](https://i.stack.imgur.com/Czpnq.png)](https://i.stack.imgur.com/Czpnq.png) (Image source: [geologic history of oxygen](https://en.m.wikipedia.org/wiki/Geological_history_of_oxygen#:%7E:text=Since%20the%20start%20of%20the,and%2035%25%20of%20atmospheric%20volume.)) 500 Mya, an event known as [SPICE](https://en.m.wikipedia.org/wiki/Steptoean_positive_carbon_isotope_excursion) caused a dramatic shift in atmospheric O2. Oxygen content in the oceans dropped and content in the air rose, probably due to a mass die-off of plankton where other photosynthetic organisms stepped in to fill the niche, pulling CO2 from the atmosphere and pumping out O2. During this 4-8 million year period, atmospheric O2 rose to [10-28% oxygen by volume](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4763753/), compared to the present 21%, and compared to the levels at what is likely the highest-elevation settlement possible for high-altitude acclimatized humans, [La Rinconada, Peru](https://en.m.wikipedia.org/wiki/La_Rinconada,_Peru), at ~10% oxygen by volume. (At less than this, [hypoxia and cognitive failure sets in](https://indoorairqualitytestingdallas.com/indoor-air-oxygen-levels-and-oxygen-deprivation-effects/).) 500 Mya was during the Cambrian explosion when most animal phyla emerged. So, no dinosaurs to contend with. Your traveler will eat, drink, and thrive on plants and pond scum for a year, with an occasional arthropod snack (all assuming no toxic qualities). If the necessary proteins or amino acids aren't present in Cambrian-era life (if inedible or without nutrients), then the traveler could possibly train for and endure a [year-long fast](https://en.m.wikipedia.org/wiki/Angus_Barbieri%27s_fast), staking out in a cave somewhere wondering to himself why he signed up for this bullsh-- (In reality, this likely wouldn't work. The human body does not store all the nutrients that it needs.) --- ### Other eras of high-oxygen content: There is evidence that [oxygen content 1,400 Mya was sufficient enough for animal respiration](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4763753/), at ~4% present-day levels, though not necessarily large animal respiration (such as us humans). It should be noted that those levels were appropriate for the animals of the time. > > The oxygen levels required for early animal respiration were lower than those needed to sustain large motile animals and were probably ‚â§1% PAL (present atmospheric levels) > > > So, unless your traveler is an immotile bacterium, this likely isn't relevant. Despite its name, the [Great Oxygenation Event](https://en.m.wikipedia.org/wiki/Great_Oxidation_Event) saw oxygen levels at 0.001% of their present-day levels (while air density was [less than half what it is today](https://ui.adsabs.harvard.edu/abs/2016NatGe...9..448S/abstract)). What makes the event noteable is that quantities of oxygen produced as a photosynthetic by-product of cyanobacteria began to exceed the quantities of chemically reducing materials, and not any particular overabundance of oxygen. Finding information about the evolution of atmospheric density is hard (this isn't my subject), but the general trend seems to be that Earth's early atmospheres were less massive than the present-day. At least half to nearly a quarter as massive. Less oxygen mass at less oxygen concentrations per volume means less habitability for larger animals. [Answer] > > How far in the past could a highly-trained survivalist live? > > > I can't come up with any sensible number. Consider this more as a reframing suggestion, looking at two aspects in particular. > > His immune system will be more than capable of adapting to ancient microbes that are hundreds of millions of years behind in the pathological arms race, so it's likely that he would not even need to purify water. > > > That is an incredible assumption. Even just in modern life, visiting a different country often means catching a cold, or a parasite, or a life-threatening illness. Heck, just riding the bus opens you up to all kinds of infectious "fun". And about purifying water, consider the advice given to gringos traveling to various areas in Mexico. Think too about historical parallels -- when Europeans were farting around in the 1400s, everyone there got smallpox as kids and just dealt with it. But when they showed up in the Americas ‚Äì where no one had any prior exposure or immunity ‚Äî the death toll was in the millions, all in one horrible mess. Now you're talking about taking a person from today and sending them back to who-knows-when. If you go far enough back, the microbes prevalent in the environment will be markedly different from what this person is used to. And "far enough back" might only be a few decades, if we're talking about things like smallpox or polio. Consider also other "fun" stuff further back, like the Black Death, or the 1911 Spanish Flu, or all the god-only-knows plagues that were rampantly commonplace in the Middle Ages. [Disease-induced quarantines and city shutdowns were so common in Middle Ages Italy that people built special windows so they could sell food and wine while maintaining social distancing.](https://www.foodandwine.com/news/plague-wine-windows-italy) Given how bacteria change over time, there's no guarantee that our time-traveler's modern-day immunizations would be effective, leaving them susceptible to tetanus, mumps, measles, whooping cough, scarlet fever... And that's just thinking about infectious disease. But what about food? As soon as you start talking about sending someone back millions of years, you have to also worry about how this person is going to eat. What plants and animals and mushrooms are safe to eat? How do you prepare them to ensure food safety? [Fugu](https://en.wikipedia.org/wiki/Fugu) can be quite delicious, but if you don't cut out certain organs just the right way, it'll kill you. [Cassava](https://en.wikipedia.org/wiki/Cassava#Toxicity) requires special processing to avoid cyanide poisoning. And how long do you have to cook them? Some toxins only break down over time, so just reaching a certain temperature isn't enough. [Botulism](https://en.wikipedia.org/wiki/Botulism#Prevention) is a thing. And some toxins don't break down no matter how long you cook them. Any such survivalist knowledge from the here-and-now becomes less and less reliable the farther back-and-away you go. ‚Üí The "modern paleontology" mentioned in the OP isn't going to address either the immunity or food challenges in sufficient detail. Staying alive for any extended period becomes iffier the further back you go. And depending on what you are exposed to (say, a variety of smallpox that doesn't respond to modern medicines), you might not be welcome back to the present! [Answer] ## Several thousand years You stated that "the time machine works only on living human flesh". Assumed blood is also transported, otherwise such a time traveller would plain outright die, there will be an issue that would immediately cause troubles to him. And this is regardless of anything else! Dysbacteriosis Symbiotic bacteria living in your intestines that help us digest food would not be transported, as they are distinctly different from the host organism. Therefore the inside of that poor bloke would end up sterile. More, there would be no semi-digested food inside, causing immediate sense of hunger. Then he would have to quickly find something to eat, and reinforce his set of symbiotes, the best source for them being milk, as it would contain compatible bacteria. If he would fail to amend his microflora, he would die of inability to digest food. Can't go further? Most likely Without bacteria in one's intestines, whatever local microbiome specimen that are able to live in the intestines of some other animal (mammal) would take place inside that human, leading to unpredictable conditions, from partial compatibility to parasiting, the latter leading to death due to no immunity to ancient intruders and overall weakness of the host due to indigestion. Therefore this time traveller is most likely limited to time ranges close enough to modern times, just because of microflora evolution. [Answer] If the traveler was prepped before the journey with a wide range of good gut biota he could possibly live further back in prehistory than only a few thousand years. Otzi the Iceman lived about 5,000 years ago and had a Helicobacter pylori bacteria in his gut still found in people today. <https://en.wikipedia.org/wiki/%C3%96tzi#H._pylori_analysis> ... A good thing might be that the time traveler's cultural learnings to do with first aid and cleanliness would presumably be going with him. If the traveler also spends a bit of time studying the edibility of plants and fungi and small animals and what they looked like in their undomesticated and non hybridized state before he goes, food won't be much of a problem. None of these have changed much in the last, say 100 000 years, and humans have grown up with them. In a sole survival situation, he'll be wise not to hunt big game. If he did succeed in bringing down a large animal, he'd be attracting multiple large predators and scavengers always ready for a free feed. That is not to say that he himself can't scavenge when it's safe. Bones and sinews make good tools. 80% of his sustenance will probably be plant and fungi based, the rest small game and eggs. His cultural learnings from present day Indigenous cultures would include how to make and set snares (First Americans), catch small lizards and fishing with scoop nets (Australian Aborigines) and thorough knowledge of edible fungi. If he ensures that his journey sets him down near a water source, he'll have shell fish laid on. [Early human migrations are said to have followed coastlines where possible.[1](https://www.worldhistory.org/article/1070/early-human-migration/) [Answer] The two greatest challenges for this man would be as follows: 1. Avoiding predators (and dangerous herbivores). 2. Hunting for meat. It is possible to train for the first issue effectively. Much is known about (in no particular order): lions, tigers, bears, orcas, crocodiles/alligators, hippos, etc. However, if he time travels to a period with radically different predators (or large herbivores), these lessons might be useless. They're highly dependent on animal behavior, which is simply too variable between species to be reliable. Can anyone really tell us how a smilodon differed from a tiger? Probably not alot, but if there are differences... our survivalist will probably discover those for himself in the worst way possible. The second issue isn't entirely the same as the first. While he will need to deal with differing animal behaviors if he wants to hunt a mastodon or whatever, hunting successfully relies on a sort of (for lack of a better term) institutional knowledge of local conditions. A great hunter in the Alaskan wilderness might be no better than a rookie hunter if dropped off in Africa or the jungles of southeast Asia. There are a host of other issues as well, but these are minor in comparison. Dealing with novel (natural) poisons, or strange geology (who knew that earthquakes could be a problem here?!?!) is something that luck alone might successfully navigate over a period of 12 months. So, considering this, the safest maximum is probably on the order of 1000-3000 years. Possibly up to 8000 (there will be some new megafauna if he goes that far back). Surviving any further back will be pure luck. ]
[Question] [ I have a Viking-inspired race living on a harsh ocean based planet with very rough and cold seas. In these seas there are giant creatures, not unlike kraken who frequently attack ships. I was thinking long and hard without an answer on how a ship (e.g. [Viking longship](https://en.wikipedia.org/wiki/Longship#/media/File:Viking_longship.png) ) could possibly defend itself against one of these creatures, and win or at least drive it away. It is also important to note that a kraken would be 3-4 times the length of the ship. The sea creatures' methods of attack include: * Rolling the boat * Ripping it in half * Sweeping people off the deck Guidelines for an answer: * The ship cannot end up like a floating pile of spikes and blades. * I'm looking for realistic weapons, tools or design features. [Answer] # Rolling attack - Have a heavy keel [![enter image description here](https://i.stack.imgur.com/0ViHh.jpg)](https://i.stack.imgur.com/0ViHh.jpg) I just wrote a big post about [naval architecture principles](https://worldbuilding.stackexchange.com/a/125039/23519), much of which applies here as well. To minimize the chance your ship rolls, attach a heavy keep to the bottom of it. In the picture above, the sailboat has a lead-weighted keel underneath the hull; this drops the center of gravity nearly to the bottom of the main hull. As a result, this 44 foot sailboat has three times the metacentric height of a Viking longship, and is correspondingly more stable. Remember, a kraken doesn't have anything to push against in the water. It will be quite a challenge to roll over a boat weighted in such a way; at least challenging enough the the Vikings can mount and attack while the creature is trying to attack. # Ripping the boat in half - Have tall trees ![](https://i.stack.imgur.com/yrsf7.jpg) The [Sitka spruce](https://en.wikipedia.org/wiki/Picea_sitchensis) grows in the very Viking-like climate of Alaska and British Columbia, and also grows to almost 100 meters. The Pacific northwest also has a variety of other very tall trees. Make the hull elements of your ship out of a few, full length boards from very tall trees. Certainly no Viking longship was ever 100 meters and the [various longship types](https://en.wikipedia.org/wiki/Longship#Types_of_longships) were rarely over 40 meters. Having solid pieces running the length of the ship will make it very hard to snap in half. On the other hand, a bending attack will cause a lot of leaking; so the crew, once the kraken is repelled, will need to keep plenty of tar and hemp on hand to patch holes between boards. # Deck sweeping attack - High gunwales [![enter image description here](https://i.stack.imgur.com/1xQOT.jpg)](https://i.stack.imgur.com/1xQOT.jpg) Instead of having crew on the deck, have them below decks, rowing. This is how a Greek trireme (pictured) operated. This will allow your crew to continue powering the ship while under attack, while minimizing the damage from the sea creature. # Animals are animals Ultimately, animals are animals. They have a keen sense of self-preservation and rarely press the attack if they are in danger of damage. Make the ship a hardened target, with the ways shown, so that it takes minutes of effort for a sea creature to damage it. Then lead a swift counter attack; hacking at limbs and appendages, shooting arrows or ballistae at vulnerable parts, etc. The attacking creature will give up soon. [Answer] If your kraken is basically like a giant squid, we can take a two-pronged approach to defend against all of your attack methods. First we want to prevent the kraken from grabbing hold of your ship to be able to rip it apart or roll it. Since the main force involved here is [suction](http://scienceblogs.com/pharyngula/2006/05/17/how-octopus-suckers-work/), we will cover the hull of your ship with metal plating with small holes drilled out of it. If we put a small gap between this and the hull of the ship, no suction can be generated, and your kraken can't grab hold. You'll probably also want a keel to help with rolling from the kraken ramming in to it. This isn't too 'viking-y' though since keels usually limit river travel. And to address the issue of crew members being swept off of the decks, we can install rails up to whatever height your crew members need to hide beneath. If necessary, we can apply the metal meshing across the top to prevent any from being snatched out of the boat. I still like the idea of a big floating pile of spikes/blades though! [Answer] The most general method of defence (IE works on most leviathans and nasty beasties) that I can think of is to tow a well lit barge or two with meat tied to them behind your vessel. Ensure your own food supplies and light sources are well hidden from the water (and paint the undersides of your boat in light colours as defensive counter shading). With luck the nasties are going to attack the decoy and not you, and you can simply sever the ropes and sail off while your would be attacker is distracted. For an even more effective deterrent, stuff the barges with gunpowder and have a single soldier ready to blow the ship if it is attacked. The resulting explosion and concussive blast should dissuade all but the most tenacious attackers. [Answer] [Greek Fire](https://en.wikipedia.org/wiki/Greek_fire) Anyone? This weapon has it all, fire scares "most" of the creatures of the seas (even humans) as scorched skin is a very very nasty wound. Your best bet is attaching it in a ballista, which could target 180 degrees so that it can shoot something somewhere near below your ship (you cant shoot below your ship). Or, a [Galleon](https://en.wikipedia.org/wiki/Galleon) equipped with multiple greek fire might have a higher chance to kill the creature due to durability of the ship, and how many greek fire (acting as a flamethrower instead of a cannon) it can equip. [Answer] Introducing the dual purpose mast. In our world masts of ships are either static, or they can be folded along the length of the ship. In this world, the mast are socketed in a tube that extends all the way to the bottom of the hull. The tube has an open bottom, and the mast is secured with pins that can be removed quickly, causing the mast to plummet down it's own length until it is stopped by the stopper attached to its tip. In this way, as the bottom of the mast is a sharp, ironclad point, the mast acts as a giant spike that can kill a kraken. If you are lucky. This method has its issues however: * The mast will have to be much heavier than usual, which will make the ship less stable. (A trade off between stability and tactical advantage is nothing special of course, see for instance fighter jets). * If you're under sail, the sails will have to be removed before the mechanism can be used. No matter how quickly you can do this, once it is done you are no longer under sail, you now pilot a rowing boat. * Timing is everything: Realistically, you will only have one chance to deploy, you better time this exactly right. If you miss then by the time your sailors have hoisted the mast back in position, you might very well be too late. * If you merely wound the kraken, instead of directly killing it, you have now attached your ship to a wounded animal 4 times its size. The odds of success with this method are slim of course, but small odds can be very useful from a story telling perspective. [Answer] All the krakenoid attacks depend on it getting its tentacles out of the water and on to the boat. Tentacles are hydraulic mechanisms without any bones, so they are not really well adapted for work out of the water: a tentacle out of water has difficulty holding its own weight, never mind fighting. So the obvious mode of defence is to hack at the tentacles slithering around on the deck. A krakenoid that manages to grab one crewman while losing half a tentacle has made a net loss, even if it can regrow the tentacle reasonably quickly; the mass of food required to regrow must exceed the mass of lost appendages by a considerable margin. If you want to go further, consider having some anti-tentacle traps built into the gunwales. These would be V-shaped slots with sharp edges. A tentacle slithering across the gunwale will slide down the trap and get cut off. [Answer] Kraken, like their smaller cousins, are traumatized by certain noises. Loud low frequency noises, such as might be made by a [carnyx](https://en.wikipedia.org/wiki/Carnyx) conveniently located inside the prow, are [highly traumatic to cephalopods](http://blogs.nature.com/news/2011/04/squid_and_octopuses_traumatize.html) and the more dulcet tones and any ultrasonics remind them of the song of their [natural enemies](https://www.livescience.com/7297-whales-attack-squid-mystery-deepens.html). [Answer] Poison. <http://www.primitiveways.com/fish_poison.html> > > In my studies of California Native Cultures, I was often surprised to > keep coming upon plant-use references documenting "fish poisons". In > widening my search, I became aware that most indigenous cultures > across the Americas and indeed on all continents in the temperate > areas of the world, used poisonous plants to catch fish... Most fish > poisons, also called icthyotoxins or piscicides, occur in several > related plant species. A variety of chemicals found in these plants > will stun fish when it passes through the gills or in some cases > ingested. The fish then floats to the surface for easy capture. > > > Squid are water breathers. If a squid is in close proximity to you it is breathing the water in close proximity to you. Aboard your ship are kegs of poison you have prepared. When under attack, dump one or more into the water. Good poisons will stun water breathers. A squid grappling you might take a few seconds to let go and by the time it does it might be too intoxicated to escape. Kill it before it does. [Answer] The biggest issue with a creature like the Kraken is most of the beast is actually below the water. It is like being attacked by an active iceberg. However, since it is an animal, it will react to pain and negative stimulus. The deck crew, being Vikings, will have axes, swords, long knives and spears, so can mount an active defence once tentacles start reaching deck level. A well coordinated attack with sharp objects will inflict damage and the Kraken will likely withdraw. [![enter image description here](https://i.stack.imgur.com/cDWZM.jpg)](https://i.stack.imgur.com/cDWZM.jpg) These guys are not entirely helpless.... Another possible defence, mentioned in another answer, is "[Greek Fire](https://infogalactic.com/info/Greek_fire)". The composition is unknown to us, but it was apparently some sort of petroleum based product which could be sprayed on enemy ships and the water around your ship using a pump. Illustrations show it projecting a flame, so it would be used much like a modern flamethrower, and it was reputedly able to burn even on water (much like a burning oil slick). [![enter image description here](https://i.stack.imgur.com/M5XJp.jpg)](https://i.stack.imgur.com/M5XJp.jpg) Illustration of Greek Fire in use So once the Kraken has been driven off by attacking the tentacles, the Greek Fire projector is used to deliver a ring of fire surrounding the boat. The Kraken will have to rise up through the flames to do a second attack, and will likely not engage once the danger is perceived. Indeed, it may retreat rapidly, since in its injured state it may well become vulnerable to attacks by the [Leviathan](https://infogalactic.com/info/Leviathan). In order to make success more likely in this dangerous venture, the hunters may have to move out in small convoys, so if one ship is attacked, the other ships can immediately reply with sprays of Greek Fire, as well as launching harpoons below the water to try to spear the Kraken itself and inflict more damage. After a while, Krakens will learn to leave ships alone. [Answer] Probably a bit advanced on the Technology front, but maybe not... A large 6-8 person rotary high pressure pump, narrowed down to a 2-3 cm nozzle would make a dandy water cannon, probably capable of cutting and debriding cephalopod flesh handily. (Squid, kraken included, are NOT notably armored.) It might not be sufficient to kill the beast, but it can put it in enough pain to make your ship an unappetizing target. [Answer] > > Sweeping people off the deck > > > This one at least you can forget about. Aquatic animals can grow to such incredible sizes because their bodies are supported by the surrounding water. Out of the water, all large aquatic animals are essentially immobilised because their bodies are not strong enough to support their own weight. A kraken may have long tentacles which would be certain death to a sailor who falls in the water, but it certainly cannot wave those tentacles in the air. Even a small octopus can barely extend its tentacles out of the water. > > Ripping it in half > > > This also is unlikely, because the kraken would need a sufficiently good hold of both ends of the boat. Tentacle suction isn't enough - it needs something to wrap round. It could perhaps creep tentacles up the side of the boat slowly, in a similar way to a caterpillar, but these would be very vulnerable to men with axes. Even if the creature has enough strength to break the ship, which seems problematic given the strength of an ocean-going vessel, it has nothing to hold onto. > > Rolling the boat > > > Now we're talking. Plenty of small boats have been lost due to whales surfacing under or near them. A heavy keel is the primary way of keeping a ship upright. If the technology (or metal) does not exist for this, or if the ship needs to be able to enter shallow waters, another possible solution is [outriggers](https://en.wikipedia.org/wiki/Outrigger). Turning the ship into a catamaran or trimaran uses horizontal leverage and the ship's own mass to stabilise it side-to-side. Now we have something less likely to fall over, we need to take the fight to the enemy. The most likely answer is the same solution to hunting whales, namely harpoons. A large aquatic animal is only a threat if it's mobile, because it can swim faster than you can sail. It has to be close to neutrally buoyant, and nothing can swim hard enough to pull an entire ship underwater - and as I've already pointed out, the tentacles can't really reach out of the water. Once the harpoon is set, you just have to haul it in and butcher it. You could add poison to the harpooning, perhaps, but the various Inuit and Scandanavian tribes who hunted whales managed perfectly well without. This isn't without risk, of course. Whaling was a ridiculously dangerous activity - but you can easily afford to lose a couple of sailors each trip. [Answer] Generally, all the mechanisms proposed are last-ditch schemes. Let's be honest: if you get to the point where the sea monster attacks you, you're done for, except for some exotic situations. What you should do is avoid such encounters by camouflaging your vessel, i.e. reducing your noise signature. Your ship can be located by the sea monster thanks to the oars whose sound resembles that of a large fish. You might switch to a different propelling system, like an Archimedes screw mounted below the deck and driven by many cranks instead of many oars. It would not give you any advantage in speed, but would hopefully make your sound unrecognizable to the creature. Alternatively, it's possible to develop techniques of sailing against the wind, and ditch the oars in favor of the sail. That would reduce your noise even further. A nice addition would be to use visual camouflage. You can paint the belly with something like the modern gray urban camouflage pattern to match the gray sky, and take advantage of what's called countershading, i.e. paint the upper part of the belly darker than the lower. [Answer] [Wow -- that mast-spike idea is really good! We never came up with an idea like that!] Most of this has been covered already, but I'm going to post anyway. My group wasn't Viking-like at the time, but they were always worried about sea monster attacks and had the idea of a removable mast for a vessel on which the mast usually wasn't removable. The idea being that the creature probably tends to grasp the mast, so if we could remove it then that's just one less thing, right? But after the removable mast was implemented it was decided that it simply takes too long to take the mast down and so the idea was forgotten. Until the group had to hide their vessel in a cove one day and after dropping anchor Rob said, "Okay; let's get to work pulling out this stupid mast!" The other party members looked at each other in surprise and said, "Oh yeah -- we have a removable mast!" and it ultimately worked to their great advantage. Anyway, the best defense my group found against cephalopods was to use poisoned spears and harpoons. Where this probably falls down is if the cephalopod is under the magical control of another intelligence or magically bound to a place, or if the game mastering is of poor quality. I could go on for three or four chapters on how to properly manage monster attacks, but suffice it to say that cephalopods are unlikely to: a) show more than their tentacles above the water line b) fight to the death c) continue to fight for an extended period of time if the opponent has any "bite" to it. Cephalopods are incredibly intelligent -- for animals. They can be very dexterous and persistent, but don't lose sight of the fact that they have only an animal-level intelligence. Of course this doesn't preclude multiple attacks from different creatures during your voyage, each time inflicting some level of damage to your vessel or attrition to your crew. [;) So, you're very unlikely to kill it because all you see are appendages, but if you inflict enough damage in a short enough period of time then it should give up and move on to easier prey. I have a special "morale-like" check I roll for unintelligent monster combat just to be self-consistent. Just throwing this out there, but kraken-like creatures are what I call "edge of the map" monsters. They're generally barrier monsters, meant to be impassible or to make you pay for getting past them. They may not fight to the death, but they should be among the most difficult to kill. In this case, the reason they're difficult to kill is because you never see them. Poisoned spears and harpoons. [Answer] Sperm whales are probably the largest predatory animals on Earth today. Big male sperm whales are quite possibly at least as large as the largest megaladons and prehistoric sea reptiles. If any sea life can smash boats, even as large as viking longboats, sperm whales can. In fact they have smashed or sank whale boats by rising under and capsizing them, by smashing them with their tails, by jumping on them, by ramming them, and even by biting them in half. The longboats of vikings were much longer, wider, and deeper than whaleboats. Would that have made them safe from sperm whale attacks? No. 19th century wooden sailing ships, many times sturdier than viking longboats, were damaged and even sunk by collisions with whales. There were also stories about whales smashing and sinking ships with their tails and even a story about a ship sunk after a whale jumped out of the sea and landed on the deck. And there were several times when wooded whaling ships weighing hundreds of tons were rammed and sunk by angry sperm whales in what seem to be deliberate attacks. So sperm whales could have smashed viking longboats by ramming them much easier than sinking sturdy 19th century wooden ships. They could probably also have sunk viking longboats by smashing them with their tails, capsizing them, jumping on them, and maybe even biting them in half. But as we know viking long boats made sea voyages of tens, hundreds, and sometimes even thousands of miles and usually arrived at their destinations safely - all too often for the good of those who were raided by vikings. So despite all the whales that viking long boats passed close by, there are, unfortunately, no reports of viking long boats being attacked by whales. So how did 18th and 19th century whalers attack and kill tens and hundreds of thousands of sperm whales? When a whaling ship spotted sperm whales it would lower whale boats that would row up to the unsuspecting whales and harpoon one. The harpooned whale would be attached to the boat by a long line and would eventually tire itself out trying to escape and then would be killed by an lance from the boat. The whole strategy of 18th and 19th century sperm whale hunters was based on the observation that sperm whales, though the apex predators of the sea, were mild mannered and non aggressive on the surface. If sperm whales had been aggressive toward ships and boats most attempted trans oceanic voyages, and many coastal voyages, would have ended with ships mysteriously vanishing at sea, and the Age of Exploration would have fizzled out, and the Age of Global Trade would never have started. Humans owe a lot to the nonaggression of whales in general and sperm whales in particular, and it is about time that a total worldwide ban on whaling is decreed in gratitude. So I imagine that in a world were Kraken exist, either they are almost always non aggressive toward viking long boats and ships and Kraken attacks are so rare that nobody worries about them, or else Kraken attacks are common and nobody ever dares to sail in Kraken infested seas. It would take a long of careful planning to establish a world where Kraken attacks are common enough for people to worry about them and plan how to defend against them, and yet rare enough that people have not abandoned long sea voyages in fear of Kraken attacks. The frequency of Kraken attacks would have to be on the knife's edge between too rare to worry about and so common that nobody dares to sail. [Answer] Keep livestock on the boat. If the Kraken attacks, dump a cow or two overboard. Hopefully it will go for the easy meal. Bonus: If you don't encounter the Kraken, you get to eat the cows yourself. [Answer] Convoys Even if ships in the convoy have no countermeasures at all, they still greatly reduce their risk because a kraken will probably only destroy one ship while the others escape. Each ship sees the same number of kraken as if it sailed individually, but has a much smaller chance of being destroyed. Another thing is that the other ships can throw ropes and rescue the crew. The Kraken might not be interested in the crew, it might only care about the ship itself. In this case, we have an economic loss but no life loss. However, 5+ ships, each with a ballista on board, could hurt a kraken enough to make it retreat. Maybe even kill it. [Answer] Some additional suggestions. * Catamaran hulls to prevent rolling * Divers trained to dive below and find and attack sensitive areas * Metal reinforcements to the hull, either lengths or banding * Some other creature trained as underwater defenders or scouts * At least some spikes to impale attacking tentacles * Large numbers of boats traveling together * Smaller attack boats launched from partner ships * Gunpowder * Explosives * Netting * Harpoons Good luck! [Answer] My personal strategy would be to find some substance that chemically attacks and burns the gigantic squishy octo- some metal or mineral that was super acidic (right? a saltwater creature would be less accustomed to acid pH? I always forget which common substances are acids and bases...) Either you could put a solid substance on the hull of the boat, or just dump sacks of a irritating or toxic chemical over the side- ideally something made from hunted animals or gathered materials that took minimal processing. Related strategy- soap or oil the boat? Did vikings have soap-making? A slippery chemical treated boat might be hard to grab AND sting the octo AND be made from something a classic viking civ would have easily available in bulk An excellent Viking-mindset-themed way to do it (attack more than defend) would be the above suggestions of adding spikes or blades to the surfaces of the hull. For cleverness, I like the idea of anti-suction panels mentioned above:they could be an extra layer over the hull so they would not need to be watertight. That being said, I thought some squids/octos had flesh-ripping hooked suckers that would probably work just fine without the suction so i dunoooo. Plus, pictures of real life octo attacks AND classic fictional illustrations both tend to show the tentacles wrapping and enveloping the target as much as using the suckers, so it wouldn't really ring true to a player/reader for a monster to give up just because the suction didnt work. (see: that youtube where a cute octopus steals a divers gopro aqnd swims off with it; the little guy surrounds it with the base of his arms as much as sticks to it with suckers- as if either one would be sufficient hehehe ) ]
[Question] [ Earth-Year: 2618. Location: Planet Hope, Proxima Centauri. Terraformation status: 97.8% Earth-like. Population: 128.596. The residents of this planet live in a paradise-like environment. The gravity and atmosphere is almost identical to Earth. 25% of Earth's flora and fauna, the most important species, are successfully imported and maintain a stable population, covering the whole planet. In any case, if one would happen to be teleported from Earth, for long he wouldn't notice any difference. The people live an exceptionally long life. Accepted age of death is 130. Colonizers were selected after a strict genetic filtering to minimize proneness of illnesses, cancer, defects etc. After colonization was finished, the colony imposed a very strict no-entry rule for non-Hope people. Then, to eliminate as many earth-originated illnesses as possible, the community entered a complete isolated lockdown lasting for exactly 1 Earth-year. This quarantine included: 1. Complete isolation of every resident from each other, in their own distinct, fully equipped apartment assigned by the Colonization Council. The doors were physically locked by authority, and any breach were severely punished. Breach of quarantine was neglectably rare. 2. Family members were also isolated from each other. Children under 10 years at the beginning of the lockdown were allowed to stay with one of their parents. 3. Physical delivery of any items was minimized to the highest possible degree. Any delivery happened by completely sterilized drones. All the delivered items - food or objects - were sterilized. 4. All communication happened by VR Videocalling. Such a call makes the other party appear like in person, but physical contact, the feeling of touch, is not possible. 5. All work where humans were needed was possible to be conducted from home-office. Physical presence was replaced by remote-controlled autonomous drones/robots. 6. Every resident had to test himself each week. The test showed the presence of 99.9% of the most prominent bacterial, viral, fungal pathogens and genetic illnesses by an accuracy of 98%. 7. Any positive tests were given their respective cure if it existed. In the very rare cases with no possible cure, the person was allowed a choice between relocation to another colony or Earth, remaining in quarantine for the rest of his life, or euthanasia. 8. All infrastructure - water, waste, air - is completely sterilized. Sterilization happens at the very apartment before entering and after leaving, and also at any place where there is a remote chance of human interaction. 9. People were allowed to keep at most one pet per person. Allowed pets were cats, dogs, or domestic rats. These animals were also included in the quarantine, and both the animal and their owner were tested for the respective animal's known pathogens in a similar way as human pathogens, excluding genetic tests. 10. After one year, only those who hadn't shown the presence of any illness for 5 consecutive months were allowed to finish quarantine. Those who had, had to wait until they fulfilled this condition. Question: Is the above method sufficient to eliminate 99.9% of the illnesses occurring on Earth, and to reach a population with no/minimal illnesses - at least for a period? What is my aim? The story is mostly inspired by COVID-19. I want to have a society which is totally vulnerable to all Earth illnesses. My protagonist would be a pilot in trouble from Earth, who breaches the isolation after an emergency landing, not knowing about the society; and causes a very bad outbreak - analogous to the Indians meeting with Europe - killing most of this society - making it necessary to enforce another quarantine. This time though the society is not well-prepared, and numerous troubles arise. [Answer] *Only for SOME* types of illnesses. Even then there are problems. Some illnesses are not infectious. That means quarantine does nothing to slow them down. (a) Genetic illnesses. For example autoimmune diseases such as Crohns, MS and ATP. (b) Cancer. (c) Chronic side effects of past injuries. (d) Mental illnesses and associated physical comorbidity. (e) Self inflicted illnesses such as acquired diabetes, alcoholism, and all the bodily damage caused by them. (f) Natural effects of being old. For example joint failure, and arthritis. (Okay maybe quarantine will slow down (a) due to slowed reproduction rates. Or perhaps it will INCREASE reproduction rates due to boredom.) From what I understand most medical care is not for curable conditions, but is routine maintenance for people with chronic conditions. Even considering infectious illnesses (bacteria and viruses) there are reasons this won't work. 1. Carriers: It is possible to be immune to a disease but still infect others. You carry the infectious cells in your body where they do no harm. But when you exhale into someone else's lungs for example they start doing harm. 2. Animals: Animals can carry disease that can spread to humans, or evolve to do so. 3. Weakened Immune System: By not exposing yourself to pathogens you weaken your immune system, and are more likely to get sick when you re-expose yourself. 4. Incurable Diseases: For example HIV will not be cured by quarantine. There will be just as many people with the virus after as before. Well perhaps there will be less due to the restricted access to medical care caused by the quarantine. . . . 5. Dormant Diseases: AlexP and Innovine point out some pathogens have a life cycle where they exist dormant in the body for years at the time. During that time you have no symptoms and are not contagious, and have no immunity, since your body is not fighting the disease yet. Thn years later you suddenly become sick and infectious. One year of quarantine will do nothing to those guys. Now you will certainly slow down a lot of human-carried illnesses with this quarantine measure. But depending on how severe point 3 is (I don't know myself) it might be a BAD idea to do such a big quarantine, unless there was some particularly dangerous illness we were trying to get rid of. Edit: For plot purposes I suggest you limit yourself to some particular type of illness being eradicated on the colony. This has been done at least once in human history with Smallpox. Another option is that something new evolved on Earth after the colony was established. Hence the colonists have no immunity to it. Edit Edit:** I am certain there is an episode of Star Trek where this happens. In some episodes the transporter beam has a scrubber that leaves behind any harmful cells or anything that is not supposed to be there. That means illnesses that develop on different planets never meet, and if someone suddenly arrives without transporter, they have no immune system for the local bacteria. [Answer] That approach might work for eradicating most illnesses, however it poses a strong risk for developing autoimmune diseases and allergies. As I explored in [a previous question](https://worldbuilding.stackexchange.com/q/163116/30492), there are suggestions that the lack of usage might drive the immune system out of its intended mandate. Segregating people alone, with no contact with unclean objects, apart from the psychological burden, will put their immune systems on a forced vacation while they are supposed to be working 24/7. Some of them at least might develop autoimmune diseases or allergies. That apart, there are illnesses with an incubation period longer than 1 year, for example Hansen's disease or some cases of rabies. For those your approach will fail. Same for illnesses caused by dormant viruses like Herpes Zoster. I guess that people getting allergic to a simple hand-shake or a freshly squeezed orange juice might be an interesting twist for your story. [Answer] ### Good idea, but there are some issues You did say "99.9%", I'm not sure exactly whether my issues are 0.1% or not, but here are the ones I found: Some people have poor immune systems: First - I'm going to direct you to a chapter of the book "What if" in which Randle Monroe delves [into this exact topic](https://twitter.com/xkcd/status/1300507567974735875) (was written pre-covid even). The author was nice enough to scan his own book in and post the relevant chapter on twitter after Covid19 got real. To summarise Randle Monroe's work - a non-trivial percentage of the worlds population have crap immune systems and will never be perfectly cured. In your case, if those rules are rigorously enforced, they will die of old age in quarantine, commit suicide when they realise they can't escape, or the government just wipes them out Final Solution style after a few years of constant positive test results. There are cases where this becomes a choice between two evils. I have a partner with MS, while on her medication her immune system is compromised, off her medication her nervous system decays. She'll have to pick between being in quarantine forever or being stuck in a wheelchair for life. At 18 she was a perfectly healthy human who would've been included in your society and passed all the screening tests, even with an unrelated MRI showing no lesions at age 19. You'll need to find and remove all [natural reservoirs](https://en.wikipedia.org/wiki/Natural_reservoir) for disease: However not covered in that work, is the concept of a natural reservoir. These are humans or animals who are able to keep a disease alive "on or within them" without showing symptoms or even nescicarily testing positive. Diseases will hide there and resurface long after they've been eradicated. Some diseases take longer than 1 year to show symptoms for: You will also have issues with diseases that remain hidden for longer than 1 year. Herpes / coldsores can remain hidden for decades. I had a number of facial infections (ear, tooth, and bells palsy) spread over about 5 years that the doctor reckons was the same underlying infection slowly migrating. My partners MS also counts here. We have no idea of the underlying cause, but it slowly appeared after exertion at age 23. You will also have issues with people carrying such small amounts of disease they don't test positive or show symptoms I can not find the link now, but I read somewhere that the reason we believe children to be at low risk of covid19 isn't because they are actually low risk, but because their immune system is more efficient in fighting them in the nasal cavity we swab while testing. Schools are full of covid19 but children keep falsely testing negative simply because they're noses are covid-free. Another take on this is HIV. After sticking to your HIV meds for a while you'll be classed as [Undetectable viral load](https://endinghiv.org.au/treat-early/about-undetectable/). This means you can't pass on HIV to anyone else, and it can't be detected in blood by labratories, and your tests return negative. Stop taking the meds, and you may eventually become infectious again. You don't need this quarantine for your plot The American Indians didn't spent a year socially distancing in disinfected apartments after they migrated to the American continent. They just were separated from Europeans for a millennia or so. You can recreate that by keeping your population separate from Earth for a few generations, which may happen naturally for a space colony anyway. [Answer] Anthrax spores have been known to survive in the soil for as long as [48 years](https://www.medicinenet.com/anthrax/article.htm) But perhaps you're asking only about viruses. These survive better in water, I think. In cool groundwater at 4 degrees C, 10% of [MS2 bacteriophage viruses can survive for 83 days](https://www.karger.com/Article/FullText/484899), and if we can assume that survivability is linear, a year would reduce the levels to 1/1000th. (I'm assuming "1-log" means "one tenth": it's not a term I've heard before, could mean 1/e maybe?) Hepatitis A virus, which is known to be transmitted through fecally infected drinking water, was found to be still infectious in mineral water after [300 days at room temperature](https://aem.asm.org/content/aem/54/11/2705.full.pdf), and to survive far longer at lower temperatures: at 4 degrees C, it took 519 days to reduce viral activation even to 1/10th (well, to "1-log" whatever the hell a 1-log is). Viruses can be frozen essentially indefinitely. A [virus was recovered from permafrost after 30 thousand years](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3964051/), raising concerns that global warming could unlock ancient plagues from the frozen ground. Importing the most important macroscopic flora and fauna from Earth, would mean there'd definitely also be vectors for novel diseases that could then jump to humans. We can't get rid of all microscopic life. [Microbiomes](https://en.wikipedia.org/wiki/Microbiome) are important. While estimates vary, the [human microbiome](https://en.wikipedia.org/wiki/Human_microbiome) is so significant that it comprises somewhere between 50% and 90% of [the cells in our bodies](https://en.wikipedia.org/wiki/Microbiota). --- But all that said: plagues, and novel viral mutations, are a game of Russian roulette. If you reduce the population of the world to 1/60,000th of the Earth's population, then even without quarantining, the chances of a plague are 1/60,000th of the chances on Earth. The odds of a mutation happening in someone's intestinal e coli to make it deadly are lower because there are far fewer someones that it could happen to. Consider that I live in a small city of some 128,000 people. Naively, the odds of a pandemic starting on that planet are the same as the odds of a pandemic starting in my city. Then reduce that by the amount of extra separation they get being on a whole planet instead of just a city - how often do they attend potential "super-spreader" events with more than a dozen people in? Probably not often. And reduce it again by the amount of variation they removed from the world's microbiome when migrating the macroscopic flora and fauna. Did they remove the earth from plant roots? Irradiate them and bathe them in UV? Dose the animals with antibiotics and antibacterial enemas, quarantine them, and so forth? They'll all initially be sickly because their microbiomes will be deficient, but the survivors will have less disease. BUT! Then multiply that by the weakness of the peoples' immune systems. Do they play in the dirt as kids? Do they catch diseases at a low level and have their immune systems destroy them without ever noticing? If not, then they will be left uniquely vulnerable to even a fairly mild plague. [Answer] ## Nope! While it's possible that you might get rid of (let's face it: comparatively minor) diseases like the common cold, there are many diseases which this won't do anything about. For the sake of time, I'll only mention the two most common types: STDs and Zoonotics. * STDs: These generally last for your whole life, unless you happen to treat them early enough. Plus, the most nasty ones have an incubation period of several decades. While you can test for these, the only practical way to get rid of STDs is to kill everybody that's infected, and most people wouldn't consider that an option. * Zoonotics: While it's theoretically possible to keep all the humans in quarantine for a year, doing it for every animal on earth isn't. Even if you could somehow manage to quarantine every single animal on the planet, it wouldn't get rid of many zoonotics; they're often harmless in their home species. Also, some diseases (such as tetanus) are caused by bacteria which are endemic in soil and on most surfaces. These are normally kept out by the skin, but can cause issues if they nevertheless manage to enter the body. Quarantine wouldn't do a thing against this subcategory; they don't need animals to survive. Even if you do get rid of all diseases, you're seriously screwing over later generations. By getting rid of all diseases, you're also getting rid of the need for an immune system. This means two things: 1. Any diseases which pop up later will be extremely deadly, and there'll be hardly anything the colonists can do to stop them. 2. They'll never be able to visit earth (or any un-sterilized colonies), as the common cold would be a death sentence. [Answer] Never say never Even with that strategy you can reduce many illness to old memories but there is many point to consider. First of all is that many things are just caused by human activity and does not depend on contamination (pneumonia, get a cold as exemple). So even in the best scenario it is not possible to avoid the body reaction to an environnement. Another point to consider is that virus and other vector can evolve and even new one can rise. If you let nature do one year you can't imagine what could rise on the next 10 years. Speaking of Covid it is a brand new virus and this is the problem, no cure, no vaccine and no immune system memory to fight it in the correct way so this could happen the week after the year of lockdown that is not impossible. Finally if you want a population that doesn't have any illness and you succeed perfectly to avoid the previous point i pointed there is the big one : you need a population. Even with the best intention you have many mental issues that this lockdown will create and one year can be enough for many suicide. With all of this lockdown many people will develop issue to interact with other people and you may reach a point where not so much people will return to a normal life and a whole generation will be sacrified. Other main point is that one year of lockdown will be one year without newborn, and with the suicide and people excluded because they were ill it will lead to a very very big crash on the demography. And not only for the next year but for many years, even generations. People doesn't take the same time to decide if they will make a baby, so for many years the generation will be very low. For me this theory is interesting to discuss because it is utilitarian vision but human being is not meant for being alone in a house, as proof history is based on creating civilization and not every individual building something. Hope my bad english doesn't affect too much the point i tried to develop. [Answer] Many diseases are caused by bacteria. They can live (or survive while dormant) in many environments, from space to kilometres deep in solid rock to being frozen in the Arctic tundra for millennia. Bacteria are also fundamental to our biology and the Earth ecosystem. There can be no life without them. So your idea of a perfectly sterile planet is a dead planet. There is no way you can remove them all, nor that you could somehow remove the ones considered "harmful". Many of them are indispensable in one context (decomposing poo into plant food) but deadly in another (try eating it). [Answer] During 1 year, the bacteria & viruses causing diseases could mutate into new strains. The folks quarantined with the new strain might build up an immunity, but other folks quarantined other places wouldn't have experienced it yet. So, when folks start interacting after a year, there could be many slightly different strains of disease all interacting at once. It could put a burden on the human immune system trying to fight off a lot of new variants at one time. EG: after a year, one quarantine place had some colds, and a new cold virus mutated. Another place got the flu, and a new flu virus showed up there. Etc, etc. Once quarantine was up, folks interact. Folks that have never experienced the latest cold & flu could get hit with them at the same time.. one hits them, weakens their immune system, so the next is right in line. This could create a cascade effect of illness.. which might overwhelm some folks (eg: elderly). Think of it this way... when kids are born, they are sick almost non-stop. Their bodies spend the first few years building up immunity to all the stuff out there, and they're constantly bombarded by it. They're non-stop buckets of illness -- snotting, puking, etc everywhere as they get sick and their body builds up an antibody library. They get over it, because they're young and relatively healthy. Now quarantine everyone for a year. Virus strains mutate just enough to create a new yearly flu that folks can get even if they've previously had the flu. So, it stands to reckon they will still mutate in someone's quarantine. Now remove quarantine after a year. All the mutated virus, etc hit every at once. Elderly, immuno-compromised, etc folks could get wiped out. Quarantines work to isolate very deadly diseases / infections. But, humans were designed to interact and share illness in order to keep up with the latest mutations in disease. When something really nasty shows up (EG: people dying right and left), quarantining can help as a last resort to try to isolate and snuff it out. But, long term quarantine and isolation won't make everything go away, it'll just lead to weaker humans with weaker immune responses getting hit by many variants at once when they start going out and interacting again. [Answer] ## Skip the Quarantine, go with incubator-grown populations: If you want a starting population utterly scrubbed free of communicable diseases, the old-school standard for sci-fi is to have a population grown entirely from embryos, and raised in the first generation by computers and robots. In a colonization scenario, it makes a lot of sense. The initial wave of human interstellar colonization could be carried out by slower-than-light ships that still go very fast. But transporting whole living humans is VERY problematic for centuries. The solution? genetically selected or engineered embryos are grown into babies inside incubators on arrival to the planet. If need be, they are genetically modified to adapt to local conditions based on preset parameters. Every embryo is selected on Earth to be free of any disease that can be eliminated. With good enough biology, the embryos may be completely manufactured and never have come in contact with any communicable disease. Even predilections for mental illness can be selected out. The same conditions are applied to all imported Earth life. The only diseases would be things like soil or intestinal/skin bacteria that are also capable of causing opportunistic infections. You can't get rid of everything (sorry). Naturally, your pilot sounds like he's got FTL technology. Subsequent FTL travel can bring the colonists up to speed on tech, but if they maintain separation from Earthlings they have no exposure to disease. Or maybe it's the FIRST contact they have with FTL-capable humans. Or subsequent slower-than-light travel is much better/cryogenics is improved/etc. That's up to you. ]
[Question] [ Imagine a Venice like city, but instead of water, it had lava/magma flowing through it. Would this be possible? Materials? Society changes? [Answer] ## The Original In Venice, the streets are made of water; gondolas carry people from point to point, and walkways stretching over the water allow foot traffic. The buildings in Venice are set on a wooden foundation, sunk in sandy islands; without access to oxygen, the submerged wood is kept fresh, and eventually petrifies. The city is, quite literally, built on the water. In fact, much of the old city is often flooded when the tides rise too high. Venice sounds like a quaint, beautiful place, doesn't it? And everyone knows that any quaint, beautiful place can be improved by adding something hot, dangerous, and toxic, right? Sure! We'll call it Venasty. ## Foundations The supports for Venasty could not be wood, obviously; they would have to be rock or metal with a very high melting point, much higher than the lava next to it. Possible, but only in a setting with enough magic or technology. Even current technology would be hard pressed to create a long-term solution. ## Height Speaking of heat, lava has a lot of heat. It's molten rock. If you've ever been near a campfire, you've felt the convection energy - it can get pretty hot, and the closer you get, or the bigger the source, the more heat it transfers to you. Lava is like that, only all the time, and Venasty is full of it. Since you want these "lava-ways" to surround each building, the buildings and walkways will have to be quite a ways up for anyone to be able to consistently live above it without burning up. Venice is built within a few feet of the water; Venasty will have to be a city of stilts and high walls, hundreds of feet above the lava. ## Transportation Transportation would not be possible in the lava flow, meaning foot traffic would have to carry the weight of produce, products, and livestock. Again: possible, but not a good place to bring your wares. It would be hard to supply those in the inner city with goods, and any heavy machinery would have to be carried in and built piece-by-piece, rather than carting it in a big wagon or barge. Building big, fancy buildings out of stone would take forever. Venasty would take a long, long, long time to build - much longer than even Venice. ## Fumes What else does lava do? It stinks. And not just a bad smell - the gasses released by lava will kill you pretty quickly. It contains [a lot of things](https://en.wikipedia.org/wiki/Volcanic_gas), including hydrogen fluoride (a super-corrosive chemical), hydrogen chloride (causes choking and suffocation), as well as lots of stuff that may not kill you, but will make it really hard to breathe, like CO2 and SO2. There will need to be a system to vent these dangerous gasses outside the city; gathering them in chimneys and venting them above the city won't work, since they will simply fall back down and suffocate everyone. ## Keeping it in Water is easy to keep in, since the damage it does to its container is minimal and slow. Lava, on the other hand, will not only try to melt the contain it is in, but will also cool rapidly, hardening into various volcanic rocks. Which means the city will need a deep pit of either super-hot lava, or a moving lava flow that sweeps away any cooled chunks. The former would make for a very difficult location to build; the latter would require constant maintenance to keep flows hot and flowing. Worse, the sides aren't the only part you have to worry about. Dropping water, or water-filled objects (like wineskins, barrels, animals, people, etc.) into lava will cause the water to very quickly boil. Depending on how the object landed and how quickly the water boils, the result may be quite violent, flinging steam and lava high into the air. If the city is high enough to be safe from the heat, it should be fine. Well, safe from lava being flung up by boiling water, anyway. ## Result The resulting city will be situated hundreds of feet in the air, with natural or man-made caverns directing the heat and gasses from the lava away from the city. The supports and foundations of the city will require constant maintenance, costly in both materials and lives. The city would constantly be covered in ash and smoke. Life in Venasty would be hot, dangerous, and difficult. No one would want to visit. One wrong move, and you slip to your death; one bad engineer, and entire housing developments could collapse, burning everything inside. In short: welcome to Hell. [Answer] # Badly. Lava is not [boiling coolaid](http://tvtropes.org/pmwiki/pmwiki.php/Main/LavaIsBoilingKoolAid). You have to deal with [convection](http://tvtropes.org/pmwiki/pmwiki.php/Main/ConvectionSchmonvection), the fact that lava is really god damn dense so it would be hard to get anything to sink into it (or stand up straight if the flow pushed against it). And oh yeah, it expels toxic fumes. You will not go [lava surfing](http://tvtropes.org/pmwiki/pmwiki.php/Main/LavaSurfing) today. [Answer] ## NOPE! First of all I don't believe that our current level of material science knowledge is sufficient to overcome this obstacle. In other words there's nothing we have that we could build those structures out of. Incidentally this is also an issue when imagining a craft which might float on lava. Last but not least, imagine living over a boiling river of lava - day in, and day out. The amount of heat generated would be staggering. Would people even be able to walk about without protective suits? [Answer] Has anyone watched the film, "Core"? 5 scientists and 2 pilots take a craft down into Earth's core to restore it's rotation. Only 1 scientist and 1 pilot returns to the surface. So my 2 cents here: It would be hot and poisonous. We have fume hoods and natural gas and geothermal power plants, massively upscaling them, we could potentially harness the energy of the lava flow for either power generation or massive air conditioning. Our knowledge of materials is enough to let us know that a suitable high melting ceramic sheath which is cooled internally by say, thermoelectric cooling or by refrigerants, could in fact be stable on lava. Also, lava is very dense, so it's easy enough to float on it even if your ship is very heavy (i.e., dense). Our best bet would in fact have to be a kind of Venice where walls of buildings are internally cooled and are made of heat-resistant ceramics, such as those used for space shuttles. Also, the lava flow should be covered by some means, possibly by obsidian or quartz skin close to the buildings, which would prevent the air near these buildings from being contaminated. Massive scale of air purification would be required. Chemical, physical, whatnot. As for the foundations, the city could be a floating one, or it could built on stilts like @ArmanX's proposition. Maintenance would be a huge concern. The protective heat shielding would need to be continually replaced from the inside, so buildings would have to built with that in mind. To fend off radiant heat, infrared-reflective coatings could be incorporated into the surface of the heat shielding. Transport is feasible (by our current ideas of economy) only via aerial paths high above the lava to be reasonably safe, uncovered, from the lava's convective heat and poisonous gases. Honestly, the main problem would be the populating it. I suspect it would be a ghost city, what with hair getting singed every time one went out on the balcony. If humans ever had to colonize Io, I would tell them to look elsewhere. [Answer] # Lava? Lava! Get the Lava out already! ![Scandinavia and the World Lava Iceland comic](https://satwcomic.com/art/bad-boy.png) That comic is true. Since lava nearly destroys anything that comes into its path, it's pretty dangerous. [When a volcanic eruption threatened to destroy the main harbour](https://en.wikipedia.org/wiki/Eldfell#The_eruption_begins), people began spraying water all over it in an attempt to cool it. Even if you kept lava in town, people wouldn't be able to survive. The ash from the lava, as well as the fumes it generates (such as Hydrogen Fluoride - that's an acid that can eat away at glass) would make for a deadly, toxic environment. The trick is just controlling it. Of course, even if you cool the lava, the heat would still stay: The rocks don't conduct heat very well - which is why Iceland is able to grow bananas :D ![](https://satwcomic.com/art/never-say-never.png) Comics source: [Scandinavia and the World](http://satwcomic.com) You may have fun reading [this comic](https://satwcomic.com/iceland-ain-t-right) as well. [Answer] OK, in an attempt to make this cool idea workable let's start with the answer from @Tamoghna Chowdhury that proposed floating buildings on the lava using similar thermal protection ceramics as the space shuttle used (note: modern variants, not those exact shields). Google confirms that the shuttle surface could handle 1,260 °C and Wikipedia quotes lava as ejecting at 700 to 1200 °C so yes, the city could float on the lava. In fact, given other answers about the density of lava this makes much more sense than trying to sink foundations. Noxious gases are, I think, manageable - there's no denying that it would be difficult to pump fresh air in from miles away and redirect all of the fumes coming off the lava but it seems achievable in the sense that it's just scaling up what metal foundries and deep mines do already. Which left me with radiant heat as the nail in the coffin for this coolest of ideas. An interesting comparison is [How much radiant heat does molten steel give off](http://boards.straightdope.com/sdmb/showthread.php?t=629332) which provides us with some information about radiant heat in environments where the base material is at 1500 °C rather than the cooler 1200 °C of molten lava at ejection. That page has anecdotal comments from a foundry worker about standing next to near-molten steel. The answer as to why this was possible is that the radiant heat is a factor of the "the temperature to the fourth power and the angular area (a.k.a. solid angle) to the first power". So it's less about how far away you are and more about how much lava is visible (feel free to step in and correct me if I'm hand-waving too much physics away). So yes, you can stand next to a small almost molten steel bar but there's no way you'd walk into the bowl of a volcano filled with lava that's 300 degrees cooler. It's the amount of lava that matters. So. If we want to have our guests (what's the point in having a home floating on lava if you're not going to invite people back there?) to be able to roast marshmallows off the balcony the key is to keep the visible lava flows strictly minimised. What we're talking about here is essentially a set of large barges with narrow streams of lava just visible between them. Most of the lava is below the heat-radiant thermal shielding that has a very high exterior temperature to prevent lava build-up but doesn't transmit that heat. What I'm not sure about is the life-times of those heat shielding materials. You're almost certainly going to need to 'drydock' barges from time to time to maintain their shielding. That said, if this works at all it'll work over a large area so you could have dry-dock facilities for individual barges as part of the city. So, will it work? What am I missing? ]
[Question] [ I am writing a hard science fiction story and I want to avoid violating known physics, while still enabling some of the classic mainstays of science fiction under the auspice of sufficiently advanced engineering. To that end, I have developed a method of interstellar travel that I believe avoids violating either relativity or causality. It is not faster than light travel. It is, in fact, exactly as fast as light. Question: The Fast as Light (FaL) system in my setting functions as follows. Does it violate causality or relativity, as described? 1. The cornerstone of the FaL system is that nothing travels faster than light (masssless energy), and that nothing travels as fast as light except for light itself. There is no way, for instance, to move a physical spacecraft faster than light. 2. Expanding on point 1, if massless energy always moves through a vacuum at light speed, then the quickest information can be transmitted between solar systems is by beaming energy between them in patterns. 3. Mass can be converted into energy, and energy into mass. 4. A sufficiently advanced civilization in my setting has a machine that translates mass into a vast and self-sustaining pattern of massless energy, structured in such a way that it collapses back into matter after a specified amount of time has passed. The pattern self-checks as much as it can, and contains enough redundancies that the interstellar medium doesn't damage it enough to destabilize it early (usually). 5. This civilization can load any cargo that fits into their machine, activate it, and broadcast the cargo out at the speed of light - as a pattern of light. The pattern of energy then collapses back into matter in its original form once it reaches its pre-set destination. 6. The practical outcome of point 5 is that this civilization can, at the cost of immense energy expenditure at the launch mechanism, send spacecraft or resources across interstellar space at light speed, though any actual crew or machinery would be shut down for the duration of the trip itself. EDIT: As AlexP said in the comments, my saying "massless" was colloquial for "without a rest mass". [Answer] There is a problem with relativity. An object traveling at the speed of light does not experience time. Your suggestion is that the object will revert to matter as soon as a certain elapsed time. From the reference frame of the light-speed object, all events are simultaneous, and the elapsed time between any two events is exactly zero. You almost have a solution. Instead of having a time based system for reverting to matter, you'll need to replace that with a system based on location. For example, the energy can turn into matter where it hits a large mass, or two beams can turn into matter where they intersect. [Answer] I see no causality arguments to be had, but there is an interesting philosophical one. If your system works on people, that proves that consciousness and the soul (if they exist at all), are successfully transferable in this way. That conundrum is one which philosophers have played with for centuries, so it would provide some fascinating background material you could add to your world. Also, you could explore the question of whether or not this pattern of light waves is measurable. If it's measurable, you open the door for using this sort of technology for things like cloning, and all the complications which arise from that. If it's not measurable, you have a society that is likely constantly trying to understand why it's not measurable. Either case may add richness to your story, borrowing from works of past philosophers. [Answer] I'm surprised no one has mentioned one of the major impediments to this form of travel. The key to your whole proposal is that you're converting the mass into pure energy and somehow encoding information in the structure of this energy to allow it to be converted back to mass when it arrives at its destination. The problem you will face though is that only a fraction of the energy sent will arrive at your destination, meaning you won't have enough energy left to convert back to the mass that was sent (not to mention you may not have the information to reconstruct the mass either). The reason for this is that [it is physically impossible to construct a collimated light beam](https://en.wikipedia.org/wiki/Collimated_light), that is, a beam of zero disperson. This is a fundamental fact of physics, because light is a wave and exhibits diffraction, causing it to be dispersive. This means that no matter how tight and straight you make your transmission beam of energy, it will disperse as it travels through space, making it so that only a tiny fraction actually hits your destination, with most of the energy missing your target. Your destination just won't receive enough energy to construct the matter that was transmitted. [Answer] No. There is already an existing physical phenomenon travelling at the speed of light, namely the light itself, and it does violate neither causality nor relativity (in fact, its speed being an invariant is the basis of (special) theory of relativity). [Answer] ## Looks legit, but there are some subtleties with physics side of things and with the design itself. @Jetpack's [answer](https://worldbuilding.stackexchange.com/a/107470/22480) and @zepthyr's [answer](https://worldbuilding.stackexchange.com/a/107529/22480) raise valid concerns: light-to-matter transmission and dispersion. ## 1) Lightbeam-to-matter at the designated location I see two and a half ways how that could be acomplished. You can take a look at [rogue waves](https://worldbuilding.stackexchange.com/a/107529/22480). Basically, the signal could consist of many waves of not-exactly-the-same frequency that once in a blue moon (at the destination) line up to produce local EM field of extreme density. High-energy physics are different from ones we're used to so there's actually a lot of leeway there. Another way to trigger the transition at the specified location would be to place an obstacle there. For example, you could shoot some pretty fast neutrinos and let your lightbeam catch up with those. Sure, the whole system would be only as fast as your neutrino beam but 0.99c is pretty fast too (and there's a room for tradeoffs - you can travel faster by investing into better neutrino beam). And, of course, the easiest way to go would be aimimg at some known obstacle at your destination system - they probably have some asteroids to spare. There, carefully formed wave package carves into the obstacle a simple reciever which bootstraps production of assembly line that uses asteroid matter and lightbeam information/energy to reconstruct the payload. I think this makes the most sense because almost all your points of interest would have some matter flying around. Transforming all payload into self matterifying lightbeam would have a greater overhead than focusing on constructing some simple reciever with some basic assembly capabilities and then bootstrapping into thing that can produce whatever you need from matter at arrival site and energy and specs via the lightbeam. If you can also harvest the energy locally then economically you beat any competition that pumps the energy at departure site. ## 2) Dispersion. At the destination, your lightbeam should have energy density greater than some cutoff or it just won't have any effect. Unfortunately, lightbeams are actually cones with a finite angle. If you increase the height `n` times, cross-section area grows `n^2` times and you would have to pump `n^2` more energy into the whole affair. If your energy expenditure grows quadratically with length and you are doing interstellar travel then you are going to have a bad time. You can work around that by using relays. You can send relays the same way you want to transmit the payload. However, using `n` relays makes you spend `n` times less energy or so. That is, your expenditure only grows linearly with the trip length. Also, relays can correct the course in case of something you couldn't possibly predict from your departure site. Implication would be that using an existing reciever is way cheaper than building your own, thus there would be, like, 1 reciever per system (actually per point of interest) and instead of jumping from arbitrary point A to arbitrary point B vessels would usually go from transport hub A to transport hub B - and self-matterifying part of your technology would be used to construct new hubs. [Answer] While not directly violating causality you do run afoul of the no-teleportation theorem. <https://en.wikipedia.org/wiki/No-teleportation_theorem> > > In quantum information theory, the no-teleportation theorem states > that an arbitrary quantum state cannot be converted into a sequence of > classical bits (or even an infinite number of such bits); nor can such > bits be used to reconstruct the original state, thus "teleporting" it > by merely moving classical bits around. Put another way, it states > that the unit of quantum information, the qubit, cannot be exactly, > precisely converted into classical information bits. This should not > be confused with quantum teleportation, which does allow a quantum > state to be destroyed in one location, and an exact replica to be > created at a different location. > > > In crude terms, the no-teleportation theorem stems from the Heisenberg > uncertainty principle and the EPR paradox: although a qubit \| ψ ⟩ > can be imagined to be a > specific direction on the Bloch sphere, that direction cannot be > measured precisely, for the general case \| ψ ⟩ > ; for if it could, the results of that > measurement would be describable with words, i.e. classical > information. > > > The no-teleportation theorem is implied by the no-cloning theorem: if > it were possible to convert a qubit into classical bits, then a qubit > would be easy to copy (since classical bits are trivially copyable). > > > [Answer] The science starts to fail at point 3 and 4 depending on your interpretation. Point 3 says that mass converts to energy and vice versa, this of course is true. Combined with point 4 it however suggests that this can happen arbitrarily, this is where the physics fail, most notably the conservation of momentum. Bad practice, certainly for science-based, but here is the [wiki quotation](https://en.wikipedia.org/wiki/Matter_creation): > > Because of momentum conservation laws, the creation of a pair of fermions (matter particles) out of a single photon cannot occur. However, matter creation is allowed by these laws when in the presence of another particle (another boson, or even a fermion) which can share the primary photon's momentum. Thus, matter can be created out of two photons. > > > So unless you can shoot one pattern of very high energy photons from one side and a second set from the other you can't do this. Another physics law you are breaking is Heisenberg. You can either know the exact location of a particle or the exact speed. Not both simultaneously. To create matter in a specific configuration at an atomic level you need to know the exact location of the colliding photon. Since you know the velocity of the photon you would be in breach of the uncertainty principle of Heisenberg. Two more points I would be highly doubtful about, but can't give you concrete evidence for, is whether you can possibly create a (stable) photon pair with a high enough energy to create neutrons and protons. Also at very high energy densities the non-linear regime of electro-magnetic waves will probably become annoying. Lastely point two might not strictly speaking be true. Some loop holes in quantum entanglement theory might allow for FTL communication (see comment) but as far as I know there is no major consensus about the loop holes in quantum entanglement. To give a gist of it, quantum entanglement is instantaneously (experimentally proven [B. Hensen, et. al., Nature](https://www.nature.com/articles/nature15759)). So if you take a pair of particles, quantum entangle them, move one particle to the other side of the universe as soon as the quantum entanglement is broken you will know it instantly on both sides of the universe. If you could do this with enough mass kept in a quantum entangled state you could send messages instantaneously. Of course you should send the mass there in the old fashioned way. Saw this method once already used in a science fiction novel very nicely. [Answer] Under the assumption of no data loss during the transfer (due to any object in the transfer medium). Your system still has two problems. 1. Energy. The amount of energy to convert mass to energy (twice) is huge, remember the formula E=mc2. This means that transfer a 10 tons of mass means 10^20 [J], which is insane. 2. Information. You are not transfering energy, you're transfering information, data related to how mass should be built. A human body has 7\*10^27 atoms, while a terabyte are only 10^12 bytes. So the data transfer assuming a single "wire" will need so much time that the system would be useless to transfer more than few molecules. ]
[Question] [ Let's say that in a medieval world, a town has been built on the coast, the location chosen as it has ideal conditions for a port town (natural harbor, lots of nearby resources etc.). It is a good sized town, burgeoning on the size of a city. However it is situated in a region that is surrounded on all sides by either mountain or forest. These are difficult to traverse in order to get to other towns & cities, the nearest of which are a significant distance away. This means that the only way the town is accessible is by boat. As there are a lot of things that are indigenous only to this region, there is a good amount of trade, so it is a flourishing town. My question is, would a city like this ever exist? Or do they exist? A town entirely isolated from the outside world except for by the sea? Obviously there are cities and towns on islands that can only be accessed by boat that can trade, but even if the conditions getting to the town by land are bad, would people eventually build a road there anyway in order to encourage commerce? Also, is it reasonable to assume that such a town would be set up in the first place? Would people construct a town via sea before they set it up via road if that was an option (albeit a difficult one)? Any other considerations for such a town can also be thrown in, but are not necessary. I'm mainly asking if such a place is realistic before I start to think about what it might be like. [Answer] The Norse Greenland colonies and Iceland prior to about 1800 serve as pretty good examples of something like what you're describing, and they didn't didn't produce cities. All colonization was done by sea, and the interiors of both islands are uninhabitable. The Greenland colonies, of course, never grew to any size and died out, but the Iceland colonies thrived. Most of the population consisted of subsistence farming, there was only one breed of cattle and one breed of sheep, so there was little local specialization and little lateral trade along the coast. Of course, there wasn't much in the way of sizeable cities either, apart from Reykjavic, and even that did not, apparently, exist as an urban concentration until the 18th century. I suspect a city could exist as you describe, as long as the reachable area were large enough, and contained a sufficient range of resources to be self-sufficient. Transportation in medieval times was slow, costly and inefficient, so the local exports would have to be exceptionally valuable in order to attract enough trade to make up any major local deficits. Furthermore, the local export goods could not be susceptible to easy short-term exploitation, such as major deposits of placer gold. Such resources would attract a lot of outside interest and produce a boom-town phenomenon such as occurred in California in the 1850's and 60's. Hard-rock mining might do, but basically any resource which can be easily located and exploited would be, well, quickly located and exploited until it ran out. Something like opium-growing might work, or any other compact, distinctive and desireable agricultural product. Exceptionally fine wine, perhaps. [Answer] It depends on the natural conditions and technology present in your setting, but it is possible. If we're talking early Middle ages, then most of Europe roughly north of the Alps was covered by impenetrable forests. It generally took people centuries to work their way through them and build roads which connected isolated settlements, which eventually led to internal colonisation and a significant increase in population density. But that was because they had no other choice. There were some places where there was an alternative. Namely these were coastal areas of Northern Europe and Scandinavia, where people figured out it was a lot more convenient to get around on boats, certainly if you wanted to ferry large amounts of cargo or troops. An example of such a region would be the Lordship of the Isles, encompassing the western part of Scottish Highlands, and the islands of Inner and Outer Hebrides. The people here had Viking-level seamanship and lived in coastal settelemnts, getting around by boat and generally not bothering with trying to build roads through the nigh-impenetrable terrain. Castles like [Dunvegan](http://upload.wikimedia.org/wikipedia/commons/thumb/7/74/Skye_Dunvegan_castle_Mac_Leod_%2815%29.jpg/1280px-Skye_Dunvegan_castle_Mac_Leod_%2815%29.jpg) trace their origin back to that period, where a clan chief would pick a suitable spot on the coast and build a fortification there, which would be accessible only by sea. Eventually, though, the inland of the Isle of Skye was cultivated and it became possible to get there by road. Where you have a castle, you can have a castle town and eventually maybe a city. This won't last forever, but might last a good couple of centuries (more if you have developmental stasis), which should be enough for your purposes. The fact that the city is considered "inaccessible except by sea" should not be taken to mean that it's completely impossible to get there by land; just that it's not feasible to do so with a meaningful army or a load of cargo. Wilderness thus provides protection mainly by restricting organised movement (and sea transport is much faster than land transport anyhow, giving you the advantage of interior lines if you were to defend the city). [Answer] [Juneau](https://en.wikipedia.org/wiki/Juneau,_Alaska#History), the capital of Alaska, is not accessible by road. It started as a gold mining camp, so it was founded explicitly for its resources, as your fictional city seems to be. Juneau was already a large city by 1920, before widespread air travel, so almost its entire connection to the outside world was by boat during that time (although I'm assuming at least a few hardened and lucky individuals made the overland trek through the forests and mountains). While not quite "medieval," Juneau's history does provide real-world precedent for a town only accessible by sea. [Answer] Short answer is yes. However the caveat is the following: You generally don't see medieval cities surrounded by mountains or forests for the sake of protection. The tops of hills were popular choices mainly because it was far easier to defend a castle or fort when you have the upper ground. If you were surrounded by mountain, then presumably you are in a disadvantageous position for defense. And you wouldn't see forests provide protection to a castle or fort mainly because A) sooner or later that forest is going to be cut down for resources and B) your enemy can hide far easier under the cloak of the forest canopy. Forests could still exist, but certainly not for protective reasons, so you would almost certainly see roads built through them. However it is also true that we're talking about fiction. If there is a sufficient cause to want to stay out of the forest or mountain that wouldn't create problems for the city, then it would be very useful protection indeed. Suppose there is a type of dire wolf that is near impossible to spot before an attack, you'd have a hard time convincing your army to pass through to attack the castle, regardless of whether or not the dire wolves would actually pose a serious threat to the army. Soldiers generally fear only the types of enemies that they can't size up. Though for all intents and purposes, there are better alternatives. Venice chose to surround themselves entirely with water, and despite not being directly connected to the mainland, it was and still is a thriving city. It is also easier to defend if you know to expect a fleet rather than a fleet or a standing army through the woods, and as these things go, when it comes to defending a city, nobody likes surprises. [Answer] # Yes. Not only reasonable, but it did happen. In addition to mountains and forest, you might consider desert. Near where I live, there are many Arabic cities that flourished in the 10th century and beyond, simply because they were a place for boats to stop, trade, and replenish water supplies. While Jeddah was a conduit for pilgrims to Mecca, the remainder of the Arabian coast along the Red Sea, in Oman (Muscat), Dubai, parts of India, were all places to stop and do the mentioned activities. Often these stops had access to fossil aquifers and wells and were stops for dhows or larger ships to/from Europe and Asia (I have a book about Venetian merchants stopping in Delma, which means "to bring water", in the United Arab Emirates). These 'refueling' stops were also an opportunity for a great deal of trade and created bustling settlements. [Answer] "Is it reasonable to have a town that is only accessible by sea?" Yes of course it is. Stop thinking of the sea as a restriction, and just another medium on which transport can travel and it makes perfect sense. Until roads were established in England, and even as late as the 18th century, sea and river routes were by far the easiest and cheapest way to transport goods and people. The industrial revolution kicked off in a little place called Coalbrookdale, not only because natural resources were available, but because the waterway (in this case the River Severn) on which Coalbrookdale sits, was a major, navigable, arterial trade route, from Shrewsbury down to the Bristol Channel and to Europe and beyond. Jon Reade. [Answer] Yes, it is entirely reasonable. Bulk transport of goods by sea is better than land transport by roads by a significant margin. If you can transport things by sea, you don't really need roads. Ancient [Phoenicia](http://en.wikipedia.org/wiki/Phoenicia) was fairly similar to your suggestion, if I were you I'd simply read up on that. The city of Tyre was outright on an island in front of the coast, but the entire area was between the coast and densely forested mountains, just like you want. The mountains were not impassable as proven by the fact that the area was conquered by several ancient empires, but Phoenicians mainly traded by sea. So basically this is only a question of the degree the surrounding terrain is impassable. In practice it is highly unlikely that coastal mountains are impassable. Your best bet would be that the locals actively fortified the gaps. Otherwise a nearby empire would insist there being a road good enough for their army to use. The basic shortcoming here is that since the terrain isolates the locals to small (in area) city states, and until industrialization most people were farmers, the isolated people will almost always have much smaller population base than potential nearby empires and consequently will be capable of supporting only a comparatively small army to protect cities very rich in plunder. That is not a sustainable equation. Obviously, if you only need the situation to be temporary this is not a real problem. Also You can place a desert beyond the mountains so that there is no larger empire. [Answer] Built to keep the British out!: > > Is it reasonable to have a town that is only accessible by sea? > > > It has been done "by design". Akaroa in New Zealand was a town designed to be accessible almost solely by sea and to be extremely hard to access by land. When it was built Akaroa closely matched your specification. While anything can be accessed by land given enough effort, Akaroa's location made it hard by the standards of the day, despite it being only about 100 miles from another major settlement that would have been deemed "potentially hostile". Akaroa - designed to be inaccessible by land:------ In New Zealand (where I live) the settlement of Akaroa formed the original French foothold in NZ while the main British settlements were almost 1000 miles to the North. Nowadays Akaroa can be accessed by a charming long and winding drive through steep hill country. When first settled the same hill country provided a welcome buffer against unexpected access from the country's interior. [Wendy windy Google map route](https://www.google.co.nz/maps/place/Akaroa/@-43.7194728,172.7190496,46337m/data=!3m1!1e3!4m2!3m1!1s0x6d33cc0a0945de13:0x500ef8684795aa0!6m1!1e1) shows how hard Akaroa would have been to access. A good feel for the sea based access can be gained [even in modern photos](https://www.google.co.nz/search?q=akaroa&biw=1280&bih=841&source=lnms&tbm=isch&sa=X&ei=5MlUVerdPOSmmAXBi4GwCQ&ved=0CAcQ_AUoAg) Guess where Akaroa is located ! :-). If you were designing a world (hey, you are!) you could hardly imagine a more purpose designed "shield" for the distances involved. Akaroa is, of course, inside the long inlet. NZ's 3rd largest city Christchurch, is located beyond the "shield" where the right hand curving coast comes out to meet it. ![enter image description here](https://i.stack.imgur.com/rH0Xl.jpg) .\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Many pioneer settlements that develop into towns in newly "discovered" countries only have sea access for practical purposes. Very early US settlements from Britain had no roads between them and what trails existed were initially unknown and totally dominated by largely hostile inhabitants who tended to take objection to be objects of discovery. (And still object to having been in many cases.) Overland routes were the domain of adventurers or expeditionary parties. The US was settled in numerous locations on both seabords long before a viable overland route was discovered. .\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ It's not a "city" per se but the East Cape is a large geographic area in New Zealand that for a long time was accessed very largely only by sea and only with difficulty by land. It had major settlements and industry which invariably used sea access for any movement of trade goods in and out. Even now it has "interesting" but usable rod access. [Sometimes even the modern road in is troublesome !!! :-)](https://www.flickr.com/photos/flyingkiwigirl/5968331669/in/photostream/) Follow photostream for otrher photos of area. The NZ "East Cape" was well known for its sheep rearing suitabilities. Up until about 1920+ all major produce from the area was brought out by boat over beautiful long wharves at Tolaga Bay and Tokamaru Bay. When the roads finally came the wharves died as commercial entities and are kept alive mainly for historical and recreational purposes. If you now [image search for Tolaga Bay](https://www.google.co.nz/search?q=tolaga+bay&biw=1280&bih=841&source=lnms&tbm=isch&sa=X&ei=icVUVZG0BIK4mwX03oHQDg&sqi=2&ved=0CAcQ_AUoAg&dpr=1) 90%+ of the images are of the wharf - a "dinosaur from the days of isolation. * Tolaga Bay wharf, at 600 metres the longest on the coast, is no longer used by coastal shipping. The wharf took three years to build and was completed in 1929, but depression, war and better roads all took a toll and it closed to shipping in 1968. Since then walking the length of the wharf has been popular with both locals and visitors, some of whom also fish from it. ![enter image description here](https://i.stack.imgur.com/gonOg.jpg) Even further out on East Cape is [Tokomaru Bay -and another majestic wharf.](https://www.google.co.nz/search?q=tolaga+bay&biw=1280&bih=841&source=lnms&tbm=isch&sa=X&ei=icVUVZG0BIK4mwX03oHQDg&sqi=2&ved=0CAcQ_AUoAg&dpr=1#tbm=isch&q=tokamaru+bay+wharf) - now derelict and dangerous at thje far end - but still lots of fun. Also see [Tokomaru Bay](http://www.nzrentacar.co.nz/blog/travel-tourism/ruin-with-a-view-tokomaru-bay.html) ![enter image description here](https://i.stack.imgur.com/Sys7C.jpg) - A century ago Tokomaru Bay was, believe it or not, a fairly major port, catering to over a hundred ships a year. It had a booming farming trade, a freezing works, a sawmill, a brick works, and a soft drink factory. All this industry went in and out by boat, with coasters ferrying the products up the coast to Auckland and dropping of supplies. The constant activity led to the formation of Tokomaru Bay’s own harbour board, and a greatly upgraded wharf – a 300m structure had rails embedded in the concrete for the small locomotive that ran the short distance from the freezing works to the port. Other facilities included the Te Puka Hotel (now Te Puka Tavern), a tennis club, a local newspaper, and two schools, and – after the war – a picture theatre. By the 1960′s it seems as though only the hotel and one school was left, and the wharf and the shells of the factories are all that remain of the town’s season in the sun. [Answer] The idea is not entirely impossible, there is a lot of cities that is only accessible from the sea, though most of them is lying on islands and that is the reason for it to be cut off. In one of my questions: [Would a medieval Arcology be possible?](https://worldbuilding.stackexchange.com/questions/9573/would-a-medieval-arcology-be-possible) it is fairly similar, a city used mainly for trading, that is dependent on food to arrive at intervals, we established that in order for a city like that to function you need to have a basic self production of food, just to get through hard times and long periods without supplies, and fresh water. It should be possible for the people living in the city to climb the mountains or enter the forest, for the adventurous and the people harvesting the trade-goods that was the reason for the founding of the city in the first place. [Answer] Historically, there were western European settlements only accessible from the sea. You had a wilderness trek to get there by land, and medievals mostly hated wilderness. The forest will get pushed back as it is used for lumber (boatyards), firewood, and fields to grow food. [Answer] People will usually take the path of least resistance first, and then later on switch to greatest profit. So would anyone build there? There are a lot of towns all over the place that were founded for small reasons. There is a place where people naturally pass, someone puts up a trading post and digs a well, Someone else builds a house, and then a couple more stay, before long you have a village that grows to a town. Obviously if this town can't be accessed by land, then the first settlers came by sea. There would have to be a good harbor. If the surrounding land was populated by hostile people at founding then an isolated section of ground would be attractive. A forest isn't good for keeping people out, but a swamp with plenty of quicksand, malaria, and other deterrents would work better. This isn't to say that no one could pass through it. People climb pretty high cliffs, and will brave some pretty nasty terrain to get where they are going, but you aren't going to easily get a road through it for trade. A road probably isn't impossible, but a boat could still be a lot more attractive. See the [Appian Way](http://en.wikipedia.org/wiki/Appian_Way#Across_the_marsh). [Answer] It is not only possible, there are plenty of historical examples of such cities in the world. In addition to the examples already provided, you can see the history of trade among the people of the Polynesian islands for examples of sea-based trade routes between cities. Note that many cities are located on the banks of a river (London, Paris), at the seashore or edge of a bay (Boston, New York, Tokyo), or on the banks of a lake (Geneva, Chicago). Historically, even when roads were available, transporting goods via ships on the water was (and remains) more economical than transporting goods over land via roads. From the 20th century onward, the advent of the standard shipping container has made large-scale sea-based trade vastly more efficient than other means of moving goods. Spend some time in a major shipping port and you get a sense of the scale of sea-based trade. [Answer] ## Do you need to build roads anywhere else to begin with? One logical possibility for how such a city would develop is if a good natural harbor was found on an island where there's no real point in putting any intra-island roads in. It could be a logical place for ships to call in for supplies or shelter from storms, yet since all the trade would happen via sea, the residents would have very little reason to go further inland. Furthermore, there may not be much if any "inland" to build roads into to begin with in addition to the possibility that inland may be impassible due to steep terrain, asymmetric vulcanism, or other obstacles. ]
[Question] [ The context: There is a population of people surviving on a lunar-analogue's surface, descended from the crew of a crashed spaceship. The rest of their society is not relevant to the question, but their technology includes cobbled together habitats and void suits that protect against some solar radiation but not all (an arbitrary amount that allows them to maintain a population, but not necessarily easily). The question: What skin colour would this select for? I'd initially say a pallid white given the lack of UV exposure, but I've recently stumbled upon research which suggest melanin provides at least some protection against gamma radiation: <https://www.news-medical.net/amp/news/20110824/Melanin-also-protects-from-ionizing-radiation.aspx> The question is, what skintone would partial protection from gamma radiation on a longstanding permanent lunar culture select for? For reference, this is for an art project where colour palette will be important, so injecting some realism into the skintone and working from there would be the way to go. [Answer] Random. I am reminded of the teeth of the numbat. [![numbat skulls](https://i.stack.imgur.com/Z0AOx.jpg)](https://i.stack.imgur.com/Z0AOx.jpg) <http://animaldiversity.org/collections/contributors/anatomical_images/family_pages/dasyuromorphia/myrmecobiidae/> The numbat has more teeth than any other land mammal. Tooth number and shape vary between individuals. It does not matter to the animal because none of the teeth are used at all. The numbat eats with its tongue exclusively. > > The variability in number and form of teeth, as well as the lack of > significant tooth wear have been cited as. evidence that the teeth are > used very little and so are not subject to intense selection pressure > (Calaby 1960). > <https://www.environment.gov.au/system/files/pages/a117ced5-9a94-4586-afdb-1f333618e1e3/files/22-ind.pdf> > > > So too skin color for your moon people. Skin color for earth humans is influenced by evolutionary pressures that have to do with UV damage / vitamin D synthesis. Absent selection pressures for or against given colors, skin color would evolutionarily drift, like the number and shape of teeth of the numbat. One could invoke this to explain why different individuals were colored differently one to the next: it is random. Note that it has taken the numbat millions of years for its teeth to reach this state. But with a small population you could have evolution / genetic drift happen faster. [Answer] > > ...Realism in the skin tone... > > > You have only two perspectives that would affect skin color. 1. The original ethnicity and/or races of the crew. In the 1960's this would have been white people. Today, there is better diversity. Tomorrow, better still. 2. Time. It takes time for skin color to change. Not years. Not centuries. Possibly not even millenium. It takes eons. The genetics of skin color takes a boatload of time. If your intrepid crew's descendants haven't experienced at least tens to hundreds of thousands of years, then their location has *nothing* to do with their skin color. The politics and social mores of the society that launched them into space would have everything (as in 100%) to do with skin color. [Answer] There would be no evolutionary pressure for a specific skin tone for living on the Moon, because -- even were we to colonize the Moon -- no one lives on the Moon like they live on the Earth. That's because people will live inside all the time, getting their Vitamin D from either food or the interior lighting. It's somewhat similar to white people living in Australia. You'd think that Europeans with darker skin would be more genetically successful, but they aren't. Why? Because clothes (and hats) shield them from the excess UV, while allowing enough to get to the exposed body parts. [Answer] It won't differ much from the mixture available in the founders' pool. The reason is simple: while when our ancestors moved out from Africa to colonize the world had the pressure resulting from lower UV exposure that allowed for the selection of paler skins, I am pretty sure your colonist would be assuming integration vitamin D, removing any need for the body to adapt. In the case they would not be assuming vitamin D integrators they would still keep the original mix for quite some time: it takes lots of generations for a character to spread, and humans are not that fast breeders. [Answer] Since skin colour affects appearance, sexual selection comes into play. Whatever skin colour their culture finds most attractive is what will be selected for. [Answer] I do not know if more dangerous rays can trigger the same reaction in the skin as UV light does, but I expect they don't. These people would most probably suffer lack of melanin as well as vitamin D. So they would need some sort of artificial sunlight source. Expect european people to be a bit paler if they do not attend their artificial sunlight exposures, but otherwise there shouln't be much difference. Tanning and skin color have very little to do with each other. One is a reaction of skin on dangerous environment and the other is a genetical predisposition. [Answer] The selection pressures for skin colour are that dark skin copes better with exposure to ultraviolet light and light skin produces more vitamin D. Your people are protected from UV so there's no pressure towards dark skin. If they're eating a balanced diet, there's also no particular pressure to produce more vitamin D. In that case, no skin colour would be preferred. The people's protection against UV exposure and sufficient vitamin D in their diet means that skin colour will have no influence on whether they live beyond child-bearing age. [Answer] As already pointed out - there would be no real external evolutionary pressure, thus sexual selection would be the way to go. Short term: -Just mixing up whole gene pool. (so mixed color skin, dark eyes, dark hair etc) Long term: Survival of the cutest. (but it is based on assumption, that there would be either a lot of time or possibility to pick designer babies) -light skin (setting all PC aside, its not a recent phenomena, but something more entrenched. According to records in East Asia lighter skin was being perceived as attractive even in times when Europeans were just considered as some distant barbarians; moreover even in Europe there were periods when lead based white makeup was top trendy) -blue eyes, blond hair (those genes are recessive, so would not manifest easily) -neonate features of Asian face -tall (it's also selected in sexual selection, and in low gravity setting it would have less drawbacks) [Answer] Gamma radiation would have no direct effect on skin color, since no pigment absorbs gamma better or worse than an equivalent mass of flesh -- or of water, for that matter. Gamma radiation is almost entirely due to nuclear energy level transitions, not electron energy level transitions (which are what produce color.) Gamma absorption (absent resonances which are not relevant to the broad-spectrum gamma you get in space) depends pretty much exclusively on the density of nuclear matter in the way, which translates pretty exactly to the mass of absorber. So to absorb significant gamma, your skin would need to get more massive (a lot more massive), not change color. It could become thicker or, conceivably, become denser by somehow developing calcium deposits. But never forget that any evolutionary change incurs a fitness cost as well, and evolution would balance the fitness cost of thicker (and hence higher energy cost and also less flexible) skin against the gains from increased gamma radiation resistance. The only effect that gamma exposure would have on the evolution of pigmentation is to potentially speed the process up by causing a higher rate of mutation. If there was selection pressure for a change in skin color, that process might well be sped up. But where the increased mutation rate took the people would depend on other things. [Answer] A detail that heavily effects the answer is what temperature is maintained in the colony. Several complex factors will effect temperature, and you can basically choose whatever fits the story. Temperature will effect how much clothing is worn. Amount of clothing then effects melanin levels. * hot->little clothing->high melanin to shield from uv * cold->thick clothing->low melanin to allow vitamin D production in the little exposed skin If you are assuming sufficient clothing to block UV, then then assumption that gamma radiation will have the dominating effect is flawed. If opaque clothing has a negligible effect on blocking gamma rays, then so will opaque skin. Since high energy gamma rays penetrate opaque clothing they will penetrate skin as well. Clothing will actually perform better than skin could. Based on the description of the environment, it seems likely that clothing will be made from animal and plant tissue. Many animals and plants will adapt to the environment faster then humans due to shorter life cycles and selective breeding. This means clothing will more quickly adapt to blocking any radiation that can be blocked than humans will. There is one way melanin might have a greater shielding effect than clothing. If a much thicker layer of opaque tissue could be used for shielding than just the skin. This could lead to the possibility of pale semi translucent skin for vitamin D with melanin rich fat, muscle, and or bone tissue. It sounds like you are wanting a very striking look and a way to justify it, this combination may be fitting. [Answer] I'm not sure if this is the convention, but after some more research and reading all these answers I think we may have come to something approaching an answer. So, it seems we have a number of factors that influence skin colour: 1. Original population genetics 2. UV exposure 3. Vitamin D production 4. Sexual selection 5. Resource cost of producing melanin 6. Gamma radiation exposure Original population genetics sets the startpoint and pre-existing genetic variety, but we can split the rest into pale-selecting and dark-selecting pressures: Pale: 1. Vitamin D production 2. Sexual selection 3. Resource cost of producing melanin Dark: 1. UV exposure 2. Gamma ray exposure From these, for our lunar population we can discount Vitamin D production (in order to protect from UV they'd have to avoid direct sun exposure, so vitamin D would likely be sourced from food). We can also probably discount the resource cost of producing melanin given that it's taken so long for numbats to lose their expensive-to-produce teeth (I'd like to find some other data points for that). Sexual selection is an interesting one, but considering the relative stability of skincolours and lack of sexual dimorphism it's probably pretty weak. So, it basically comes down to relative exposure of UV on the earth's surface to gamma radiation on the moon. If the radiation on the moon is equivalent to northern Europe we might see a gradual slow movement towards paler skin. If it's equivalent to Africa (or higher) then we will likely see a move towards darker skin (potentially rapidly). Unfortunately, there's a maddening lack of studies comparing the relative damage of gamma ray and UV exposure. Closest I've come to finding something is [a load of people stating how difficult it is to compare them and one guy who's actually done something](https://www.researchgate.net/post/How_comparable_are_gamma_and_UV_radiation) and found that 6J/m² of UV exposure and 4 Grays of gamma exposure killed the same amount of chicken cells (conditions unknown so not the greatest test but it's all we've got). From [this study](http://pubs.rsc.org/en/content/articlelanding/2016/pp/c5pp00419e#!divAbstract) we can see that in Europe we are around 200J/m² per day. In central Africa we are around 5000J/m² per day. The highest figure I can find quoted for average radiation on the lunar surface is 120 millirem per day (others hover around 50 millirems), which converts to 0.0012 Grays of gamma radiation. Practically nothing. Wait, why are we scared of gamma radiation on the moon again? Unless they're quoting shielded figures, or the 6-to-4 ratio of that guy was for one layer of cells (so gets multiplied by each layer of cells the gamma rays reach that the UV rays don't). The only thing I can see that would be a problem gamma-radiation-wise is the recommended [maximum radiation dose for fetuses](http://news.mit.edu/1994/safe-0105) (50 millirems per month plus the 25 millirems background). So, sod all effect on adults but very dangerous for kiddos, unless I'm missing anything major. Oh, and apparently during an 18-month study on Mars there were 2 events which saw radiation increase to 2000 millirems per day (0.02 grays). So, all of that weighs out to a very slight selection pressure towards paler skin with a cultural trait of hiding pregnant women within rad-shielded bunkers, or a strong selection pressure towards jet-black skin in order to protect their unborn children. Edit: apparently the safe level for radiation exposure in US legislature is 5000 millirems per year, or 13.7 millirems per day. Lower than the level our lunites will be receiving. So, leaning towards the jet black option of the two above... ]
[Question] [ Behold the Khajiit; [![enter image description here](https://i.stack.imgur.com/2wySB.png)](https://i.stack.imgur.com/2wySB.png) Born from the insanely popular game series, Elder Scrolls, the [Khajiit](http://elderscrolls.wikia.com/wiki/Khajiit_(Skyrim)) are a race of cat people who live in hot jungles. From the moment I saw this race, I fell in love with them, their natural sneak and unarmed attack made me want to play as them in every play through. Recently, after yet another play through I wondered if it was even possible for the Khajiit to exist. Biologically speaking, could the Khajiit exist? What evolution would support them? --- A list of all of the Anatomically Correct questions can be found here [Anatomically Correct Series](http://meta.worldbuilding.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798) [Answer] Cube knows that Khajiit look like customer's world Lynx. But Cube is going to base realistic Khajiit on another, smarter cat. Anatomically correct Khajiit is based on rainforest jaguar. The reason being that jaguar is much smarter cat. Just like Khajiit, see? Tiger is strong in body and lion is strong in number, but jaguar is fierce. Lion and tiger are afraid of crocodile and alligator, but jaguar hunts alligator. Jaguar is versatile too. [Jaguar has many tricks up its furry sleeve](http://listverse.com/2011/01/15/10-deadly-tricksters-of-the-animal-world/): > > It was recently discovered that the Margay, a small arboreal feline from Mexico, Central and South America, has the ability to mimic the calls of baby monkeys in distress. This, of course, attracts worried adult monkeys which can then be attacked and devoured by the Margay. Scientists who witnessed this while doing research in Brazil just couldn’t believe their eyes, but natives were not surprised; they informed the scientists that Margays can also imitate the sounds of other animals, such as the tinamou (a flightless bird) and the agouti (a large rodent). Even more, the natives claim that pumas and jaguars also use vocal mimicry to hunt once in a while. > > > ...And... > > (...)one of the jaguar’s favorite foods is fish. In order to obtain it, they say, the jaguar has developed a clever trick. It taps the water surface with its tail to mimic a waterlogged insect or fallen, floating fruit. Fish soon swim to the surface to investigate the lure and the jaguar then scoops them out of the water with its paw. This makes the jaguar, according to natives, “the most cunning animal in the forest”. > > > So jaguar already has the brain. But how about the body, customer ask? Let's say that a particular set of cunning jaguar develop opposable thumb, to climb tree and rock better. Now jaguar can make use of handheld tools, just like you primates do. Perhaps the primitive cave Khajiit made spears or fishing rods out of tree branches. Perhaps they used their hands to build boxes to sleep in during the night, using tree bark and mud. Cave Khajiit then had to evolve a bipedal posture to have hands free for tools. A bipedal posture could not support a cat's malleable body, so vertebrae became more hardly fused, less flexible. That's why Khajiit have straight back that does not easily curve like you primates and scaly Argonian do. But Khajiit kept other things like [free-floating clavicle](https://en.wikipedia.org/wiki/Cat_anatomy#Skeleton), which is why Khajiit is so nimble with arms. Khajiit is good climber because Khajiit has retractable claws. Also handy in a fight, as Khajiit does not need a knife. But Khajiit keep claws hidden and safe when Khajiit shake your hand after a good deal is made, see? Khajiit tail is vestigial. Tail can shake and move, but does not serve to balance the body anymore. That is because tail is now much smaller part of Khajiit weight to make a difference. Khajiit can see better than you in the dark because of [tapetum](https://en.wikipedia.org/wiki/Tapetum_lucidum). That is an organ that makes light hit the retina twice. Khajiit therefore needs less light to see the same object, hence the slit pupil by day to filter excess light. Please stop casting Candlelight now. Now Khajiit knows what customer is going to speak about trade. Khajiit are good in trading due to culture. There is no neurological nor genetical predisposition for trading. Some Khajiit decide do sleep with lizzards and become adventurers instead. Bah! An arrow to their knees! Last but not least, Khajiit have better smell and hearing senses than customer. That is just the way Khajiit are made. But other than senses, Khajiit brain is same as customer brain. Khajiit are smart and educated, and in some worlds elsewhere (sorry, Khajiit could not resist!) Khajiit have built advanced society with technology. There is a world where Khajiit even built super advanced flying machine to fight crime! [![These Khajiit are from SWAT Kats, a magically animated drawing of sorts](https://i.stack.imgur.com/tDXvx.jpg)](https://i.stack.imgur.com/tDXvx.jpg) [Answer] I'll be focusing my answer on a specific piece of the question here: their legs. Khajiit look like they're essentially bipedal cats, which means their legs will be rather different from ours. Humans are plantigrade, so they walk flat on their feet; the toes and ankle are on the ground, while the knee is about halfway up the leg. However, the legs of these Khajiit will be digitigrade, like in [this question](https://worldbuilding.stackexchange.com/questions/40584/humanoids-with-digitigrade-legs) and its answers; they're effectively going to be standing on their toes. Digitigrade legs are intended to bear the weight of an animal over a flat plane, preferably on more than two legs; stand them up and put all their weight directly on just two legs, and those legs will fold up and collapse like an accordion; they can't easily bear that weight. To counteract this, the joints need to be made stiffer, so they aren't prone to bending as much. The Khajiit ankles and knees will have to migrate up the leg (in comparison to a human leg) to minimize the bending, which will probably make it look double-jointed; I can't tell you the exact proportions, but try to imagine if the human knee moved halfway up the thigh while the ankle moved up somewhere in the lower leg, as the human in question was standing on their toes: that might give you a good picture. This is also going to compromise their balance; humans are balancing their weight on two feet between ankle and toes, but the Khajiit have to rely entirely on the toes. This isn't quite as bad as someone standing on stilts (although immobile toes would make it that bad), but it's still going to be difficult. The Khajiit are going to have trouble standing still without losing their balance and stumbling or falling. This won't be nearly as bad if they stay on the move or have something to brace against, though. However, digitigrade legs are not all downsides; the Khajiit will be able to run considerably faster than humans, and they're going to be more nimble as well. A digitigrade leg allows for much more leverage in the foot, which means each step can have more thrust put into it and thus more speed. I think they'd do great as fencers or other duelists, probably swordsmen as well, but they likely will underperform if you tried to use them as hoplites or similar heavy infantry. In a hypothetical army of Khajiit, you'd get good skirmishers and light infantry, but lousy heavy infantry; they'd be nimble, but they wouldn't be able to keep their footing in the event of a collision of heavy infantry, so one solid charge would rip them apart if it connected. I'm not sure what their resting posture might look like; if somebody else has any better ideas here, feel free to point them out. However, the position of the knees and ankles, the limited flexibility they have (too much flexibility and the legs won't be able to stay straight, leading to the accordion problem I mentioned); that suggests to me that sitting in chairs will be awkward at best, and unworkable at worst. Going down to one knee (with the other knee still above the ground) would not work given the proportions of the legs, since the knee is simply too far away from the toes, but kneeling on both is possible if the knees are capable of bending that far. A cross-legged position is a dubious prospect, but it might work, albeit with the feet sticking well out. [Answer] This and the Argonian are surprisingly the only two of this series that I could see that involve the evolution of bipedality. Whether digitigrade ("furry style") or plantigrade (human style), the important thing about bipedal locomotion is that it requires a massive overhaul of the entire body structure, in evolutionary terms. Let's consider the skeleton first. Obviously, what the legs connect to - the pelvis - must change, to support the changed leg position, and force from what was previously behind. That's a 90 degree change. Because of the extra weight borne, the legs themselves need to be made thicker, heavier and more muscular, while at the same time becoming more columnar - the weight of the whole body needs to be able to rest through a vertical pillar of bone, not a zig-zag, or standing will require constant work by muscles. The spine, which previously was a splendid cantilevered system, with head and tail balancing out the spine and creating a spring that could be used for great leaps and bounds, is now vertical, and under constant compressive stress - this requires bulking it up significantly, and making it far less flexible. The forelegs are now free to become more flexible, though for this to have any significant evolutionary advantage, there'd need to be something like brachiation (walking while holding to branches). The ribcage no longer ties running to breathing, as it won't be compressed at every step. The deep keel that ws once important no longer matters and instead a wider, flatter chest is better because it gives a wider grip and means you can cling to more stuff in an armload. The fixture of the skull to spine needs to rotate forwards 90 degrees to be supported by the spine, and since it is no longer providing a counterweight to the organs, it needs to be balanced atop the spine. Looking from side to side becomes a rotation rather than a flexing of the neck vertebrae, which means rebuilding them and reducing flexibility once again. Then there's the soft tissue. Sex, which used to be a simple matter, becomes complex, as genitals move around with the pelvis, and the legs start getting in the way, as do the new buttocks, which are required to make any kind of sitting comfortable (though the tail could be co-opted for this I guess), and for storing the massive muscles required to merely remain upright while walking. Internal organs, which used to be pleasantly supported by ligaments suspended from the spine, now sag downwards, causing prolapses. Muscles need to be moved around just to keep all that in place, but hernias still happen as stuff bursts through. The heart, which used to only have to pump blood up and down a few feet, now has to handle pressure differences of perhaps six feet, and the legs require a lot of blood for their newly-strenuous work. The brain becomes subject to blackouts when standing up, so various filters, gates, and pressure sponges need to be developed to prevent that. For all that to happen, there needs to me a MASSIVE evolutionary imperative to cause such large changes. There are various hypotheses about what happened to humans. Some claim that we just sat under trees and needed to be bipedal to reach up into branches, or hang from branches, etc. Others say it was to carry things, citing tool use. Others say it was because the hot midday sun caused us to become bipedal to reduce our surface area to the sun. My favorite, though I'm very biased, is that we went semiaquatic, and needed our hairlessness, blubber, and bipedality for wading and brachiating in flooded mangrove swamps. In fact, monkeys in such swamps tend to move around in exactly in this way. For the Argonians evolving in the swamps, then, bipedality can arguably make sense. But Khajiit are a harder problem... [Answer] While very informative (and hilarious), I don't think the current answers approach the question in the best manner. They seem to be trying to take a cat and transform it into being human-like, while pointing out the incredible skeletal changes that have to happen along the way. But that's likely not how they would have evolved. Our current "cats", both big and small, are not suddenly going to change their evolution niche from top killing machines to... and I don't mean to insult the khajiit or promote the game's racism but... tool-using, sneaky humanoid thieves. I personally think it would be easier to take a human and think about how we might have ended up with the cat head structure, fur, and a tail. However, the whole argument is pretty much moot within the Elder Scrolls world and lore, which states that deities created each of the races. Its actually a decently long creation story full of characters but here is the part about Khajiit, > > She [Azurah] was told to take one of Nirni's children and change them, making them the fastest, cleverest, and most beautiful of creatures, naming them the Khajiit;... they must be fashioned as the best climbers... lastly, that the Khajiit must be the best deceivers, able to hide their true nature from others. Then Fadomai died, and Azurah left to join her kin. > > > Thus, if we are to believe that these Gods exist (and they prove themselves to exist, many times within the Elder Scrolls world) and that Azurah specifically created the Khajiit, we can't really argue against their evolution, or lack of one, without also arguing against the very nature of that world. One of the khajiit's physical attributes would have to break the laws of in-game physics (easier to do on some platforms than others) to claim they are unrealistic within their world, but luckily nothing within their or our world contradicts bipedal cats [Answer] This could evolve in real life. fairly unlikely, but then again so are humans. Leopards already climb trees and cache their kills. so if a group of leopards spent more and more time in trees over millions of years they would start to look like cat apes. then they transition to be on the ground more for upright hunting and wading through shallow waters to become bipedal. digitigrade feet would mean they likely keep the tail even when walking upright. plantigrade feet would probably lose the tail. I dont see them keeping their fur after discovering fire unless they are against clothes and in a decently chilly environment. thats how human evolution worked. ground based mammals transitioned to trees then transitioned back to ground while wading through water and hunting upright. no reason for the cat apes to lose their digitigrade feet. a larger big toe and more flexible ankle is more then sufficient. if their feet turned into hands same as their front paws then you would have plantigrade feet but no tail. humans are not very strong or fast but we have a lot of endurance. digitigrade is more likely to be fast and strong and maintain their fur while plantigrade is more likely to become endurance runner like humans did. this is all unlikely. felines in general are pretty successful hunters. they are hypercarnivores for a reason. but lets say that leopards were able to digest some small amount of plant matter as a supplement until they become generalist omnivores while also staying nearby the trees, then it becomes much more likely. ]
[Question] [ A group of behaviorally modern humans was cut off from the rest of the earth-like planet. At the time of the separation, humankind had reached a technology level including cattle ranches, brass, writing, and cities. ([Same cataclysm](https://worldbuilding.stackexchange.com/questions/1241/humans-born-without-legs-how-would-they-thrive), different ark.) About four millennia later,\* they were contacted again, but all of them were (or at least looked and acted) female. I can think of three ways this might have happened: ## Hermaphroditic reproduction It takes two women (and no man) to reproduce. Some vertebrates are sequential hermaphrodites, beginning as one sex and becoming the other later in life. These include clownfish (cue the "Finding Nemo is doing it wrong" nitpickers) and frogs, which inspired Ian Malcolm's famous line in Jurassic Park: "Life, uh, finds a way." Among mammals, some species of mole vole (Ellobius) and spiny rats (Tokudaia) have two X chromosomes, with sex determined in some unknown manner. ## Males that look like females Hyenas are male and female, yet females produce huge amounts of T at puberty, and they're dominant over the submissive males. Feminization would invert this, with males becoming feminized with things like gynecomastia. Male lactation isn't unheard of in the real world; it's seen in Dayak fruit bats, occasionally in goats, and even in humans suffering from galactorrhea. ## Males hidden away Instead of diminishing to near nothing, the sexual dimorphism has become so extreme that only females appear in public. It need not be as severe as the difference between male and female anglerfish, but a pile of sex-linked genetic disorders becoming fixed might cause the appearance of a man to become shameful. So which of these options is the most biologically plausible and why? Or what other mechanism could make all individuals look female to an outsider contacting this race for the first time? \* This would have to be a rapid change to happen within a 4 ka timeframe, but this timeframe is negotiable. A separation after emergence of humanity but long before the Bronze Age is also acceptable, as the separation date of 4 ka before present may be mythical. [Answer] ## Considering the restrictions of most biologically plausible with renaissance technology, the most likely is males look like females, there are real options for this. This is not hard a few mutant genes and a population bottleneck can severely cut down on the number of male looking males. when a small population gets cut off from a large one often odd genes get drastically increased in the small population due to a tiny selection of initial genes carried over by luck. This would be the [founder effect](https://en.wikipedia.org/wiki/Founder_effect) and it would be hard NOT to get some kind of founder effect in your scenario. Real examples from human history exist, including surviving populations from shipwrecks with very small numbers of individuals. You just need few surviving males mostly composed of anatomically feminine males which already exists in the human population. After anatomically masculine males become extremally rare a cultural shift and sexual selection does the rest. Anything from fashion, to a crime, to simple lack of interaction makes females see feminine males are more attractive at which point sexual selection takes over and eliminates the masculine males genes from the population. Interestingly prolonged isolation could also lead to a stabilization of what in the wider population are highly variable conditions as control genes evolve. Nothing about this requires technological intervention and uses existing human biology and variation. Possible options Aromatase excess syndrome causes feminized males and hyper-feminine females. Interestingly for you, this almost never prevents males from having penises no matter how female they appear although they are often very small (micropenis). Its very rare but also hereditary and poorly understood, perfect for a fiction story. Androgen insensitivity syndrome in humans can (among other possibilities) make males who appear to be females in everything but a small difference in genitalia who are capable of insemination with supplementary testosterone (which might be achievable from local plants for extra flavor). Highly variable but also fairy common. You may also want to look at Güevedoce in Las Salinas of the Dominican republic for some ideas. [Answer] Once you reach a certain technology level males are essentially obsolete. Testosterone and increased physical prowess is irrelevant when all combat comes down to ranged weaponry and engineering. Beyond contributing DNA we are not at all relevant to reproduction either. You would not need to advance beyond our current technological level much to be able to take stem cells, convert them into sperm cells, then inseminate an egg with them. So you have a hypothetical future society where, couples (or singles, or multiples) form a relationship and decide to have children. Sperms are generated from the paternal partners (or taken from DNA banks) mixing their DNA appropriately and selecting for compatibility, desirable attributes, etc. (Of course they always select for female at this point too), the egg is artificially inseminated then implanted. This results in a biologically human (but heavily selected for intelligence, attractiveness, etc) entirely female population. It would be theoretically possible to have a male baby but if someone did that it would most likely be considered shocking and the child would cause a stir wherever he went. [Answer] I would go the way of either parthenogenesis or [radical feminism](https://en.wikipedia.org/wiki/Sexmission). Given the dogma: * Most of the wars are begun by males * Male reproductive hormones also lead to aggressiveness * Thus, all males are responsible for wars * Thus, if there are no males, world will be better place You can build all-women society using [today tech](https://en.wikipedia.org/wiki/Sperm_bank) by freezing the sperm of males and breed only women by using [in vitro fertilisation](https://en.wikipedia.org/wiki/In_vitro_fertilisation) If you are gone with sperm reserves, you can breed males in controlled area for more sperm [Answer] Feminizing pollutants. Currently changing fish female in our oceans. Going to require an advancement in your technology, however. Wolbachia bacteria that affect humans, rather than butterflies. Females with XY genes: complete androgen insensitivity, or CAIS. Will result in a lot of 'females' who don't have wombs/ovaries. In theory, this should be bred out of a population by remaining fertile men who throw resistant offspring; and thus will take over the population dynamics. An aside: If you do keep males, you're going to have to make them much wider-ranging. You can fight inbreeding in 95% female populations (like green turtles, due to climate change) by having males range a lot. Each male gets a ton of mating opportunities, but no local overlap. <http://www.sciencedaily.com/releases/2012/01/120124200106.htm> [Answer] I'd go with religion. If males are redundant for things other than reproduction, ie war is either non-existent or not dependent on physical size and strenght or heavily ritualized, it might make sense for the gender ratio to be skewed widely in favor of females and males to be hidden. Details could vary widely, but there are some basic considerations that probably would be nearly universal. The civilization would necessarily be matriarchal. This would imply low importance on farming, hunting, mining, fishing and other forms of sustenance that are typically male due to absences from home and family. Although that is mostly relevant in the early stages, if society is already heavily matriarchal, women will simply do the traditional male jobs. These divisions are more about some things being more convenient for males than women being incapable of doing them, so if there is a high inconvenience factor with using males, matriarchy will be stable enough. Civilization would probably also be entirely matrilinear, with males used as breeding stock, and traded between different lineages. This is actually relatively "realistic" way of getting practical selective breeding with humans. Only the sons of notable women or men who do well in competition would be interesting for trade. And with "realistic" I mean it would be much more likely to work than the eugenics programs proposed in early 20th century, as selecting based on good performance is fairly close to how selective breeding with animals and plants has worked just fine. There would be a mechanism for killing off excess males. Either the sons of "low-status" females would be ritually sacrificed soon after birth or males would engage in some form of ritual contest with lethal consequences to losers. Or both. Easiest contest to set up would be ritualized warfare. Either roman style gladiatorial games or aztec style flower wars (or whatever they were called) would work just fine if ramped up enough. Most likely would be starting with sacrifices and then adding ritualized warfare when civilization gets more affluent. Affluence adds both ability to raise "useless people" and demand for entertainment. Gladiatorial combats used to be quite popular. If most males were killed soon after birth and the rest held in secure locations due to being either valuable breeding stock or valuable future gladiators, the society would for all practical purposes be "all female". For that matter as the sacrifices, gladiatorial combats and even breeding would likely be sacred religious rituals not accessible to non-believers, it would be difficult for outsiders to see evidence of males even existing. Interestingly, there isn't really any need for a religion like this to be unusually malicious or brutal. (The "bad stuff" is contained and separated from normal life.) So discovering this side of their new friends might be a shock to outsiders. The difficult part would be explaining how such society is created. But if the initial seed colony has high enough gender ratio, people might simply decide to keep it that way. Especially if there is some external factor (read famine) forcing very difficult decisions. This would actually fit with the lack of farming. [Answer] TimB's answer is the most comprehensive, but I wanted to add another possibility from a book I recently read, 2312 by Kim Stanley Robinson: ## A Gender Revolution In that book, gene therapies and the biological sciences have advanced so far (and frankly it's not that far from today) that people can cosmetically alter their primary and secondary sexual characteristics easily. Many, if not most, people end up experimenting with both fathering and mothering a child at some point in their lives, and many maintain both sexual organs (for example, enlarging the clitoris into a small, functional penis) so they can play either role as the mood strikes them. It's not hard at all to imagine that a society like that might eventually tip the scales toward people preferring one gender over the other, and as TimB pointed out, it would almost certainly be female. What would result is a society of entirely, or almost entirely, female-looking citizens, but whose reproductive organs weren't the binary "male-or-female" options we (for the most part) have now, so the species could easily continue to reproduce. [Answer] A world almost exactly as described in the original question has been constructed in Herland by Charlotte Gilman, back in 1915. The only real difference is that in the novel the society is cut off for about 2000 years instead of 4000 High in the mountains of South America, a group are cut off by geologic upheaval, and through social uprising the remaining men are killed. The book describes in great detail their world, seen through the eyes of 3 male visitors, and covers how they reproduce (parthenogenesis), as well as the unique social structure they have developed. You can read it here <http://www.gutenberg.org/ebooks/32> [Answer] Many of the physical features associated with a feminine appearance, like protruding breasts, exist because of men and are in no other way helpful for survival (breasts are helpful, but their current size in humans is massively more than what is biologically necessary for holding milk and feeding young. Also they are present even when a women isn't lactating). Whatever option you choose, your resulting women must also be lesbian ( and find the current-species feminine secondary sexual characteristics attractive) or any option that relies on change over evolutionary time will also remove a lot of what is currently considered a 'feminine' appearance. The technologically-performed gender revolution and the secret male options thus are the ones which are viable. However, you mention that the persons in the society 'act' female. This is not really possible in the revolution scenario as over 4 thousand years of time cultural fragmentation is all but certain, and what gender ("acting feminine") means is largely a cultural construct. 4000 years of time passed with the technologies you are talking about and ample space and, consequently, resources should result in populations spread over most of the globe. In order for a process to end up with the results you want, we need a society that: lasts 4000 years or eliminated all other differing societies in the past breeds and has bred women to look 'feminine' Culturally enforces gender roles for women, despite having no (visible) men. Of the options mentioned, I think the hidden males option is the most likely to work, but the implementation you suggest is unfeasible as it would result in male mate choice not being a selection factor in breeding. Culture is a very strong force, and a cultural ban against looking male in public would have the same effect. Humans also all like the look of attractive women, whereas only females like the look of attractive men (Homosexuality notwithstanding). Thus a culture that encourages men to look and act like women so we can all get along is fairly plausible. Alternatively, women have been historically oppressed by men in many societies and some humans in behaviorally modern society seem to seek to restore the former, strictly patriarchal, gender paradigm. Given the cataclysm you are describing it is possible that such a former minority might take control and lead the society into a sort of anti-Feminism. Provided the male leadership secures the means of production and technological research, they could probably keep the female population under control indefinitely, assuming they aren't opposed to infanticide to keep the gender ratios optimal and kill off any males with pesky egalitarian notions. One of the horrors of modern technology is that it allows power to be concentrated easily in the hands of a few, so while such a distopia would not be possible in the Stone Age, it would not be terribly difficult with Post-Industrial Revolution technologies. Because the males in such a society would originally represent a much smaller percentage of the population than the female and would need to maintain such a ratio in order to keep the male population from benefiting from female choice, and because such a society needs constant technological advancement in order to stay incontestably ahead of the females' attempts at rebellion, and because only males can be trusted to serve as scientists, political leaders, military brass, and other positions capable of overthrowing the patriarchy, and because direct interaction allows the possibility of assassination or lynching, the males of such a distopia would not be publicly visible. [Answer] In H.G. Wells' [The Time Machine](http://en.wikipedia.org/wiki/The_Time_Machine), humanity (at least the above ground portion of it, or the "Eloi") appears to be entirely female. He suggests (explicitly or implicitly, I don't remember) that they reproduce asexually. So there is Wells' idea of most biologically plausible ;-) --- Note: Even though this is just anecdotal evidence, I believe that this is a good answer because H.G. Wells is known to stick to science as much as possible -- from [Wikipedia](http://en.wikipedia.org/wiki/H._G._Wells): "Wells's earliest specialized training was in biology," for whatever that's worth. [Answer] It has been suggested that the male-selecting Y-Chromosome is gradually diminishing in size, and that in the future, it will disappear (It has happened in some species, but it is debatable if it could happen in humans). One possible, and potentially most likely outcome for humans in which the Y-chromosome has disappeared and no other gender-selection mechanism replaces it is for hermaphroditism - there would be one gender with both a penis and a vagina. With a only a little bit of evolution, one undifferentiated foetal gonad could descend and could become a single testis, while the other remains internal and becomes an ovary, or perhaps (and less likely), the foetal gonads could each split in two, the two lower halves becoming two testes and the two upper halves becoming two ovaries. The appearance of a hermaphroditic human would most likely be essentially feminine, with a penis, as mate selection would likely be based on potential for motherhood, and there is little evolutionary pressure to diverge from the human female ideals that evolved in two-gendered humans. [Answer] Look at how the ovum develops: In addition to the ovum three additional bodies are produced with 23 chromosomes. These are all discarded and die. Extrapolation from lower animals suggests that 1 human child in a billion should be the result of such self-fertilization although no examples of this have ever been discovered. The result of such a fertilization is either a clone of the woman or what amounts to incest with herself--with the high genetic risk this entails. There are no Y chromosomes around, all the children are female. To get a purely female civilization: They suffer some major calamity. All the men are killed, the women are pushed to the brink of starvation. In their desperation they discover that a certain plant is actually edible, after things return to normal it is discovered that consumption of that plant greatly increases the rate of such self-fertilization. (Nobody else has discovered this because the plant is known to be poison--but it actually is only poisonous to men.) You get an all-female society that eat the plant in question when they want a child. This requires a plant with some very particular properties, it doesn't require technology. I think it fits what you're looking for. [Answer] Funny that no one mentioned real answer, which allows for society of pure females could exist, even today, on our own Earth. [Parthenogenesis](http://en.wikipedia.org/wiki/Parthenogenesis) - form of asexual reproduction in which growth and development of embryos occur without fertilization. It occurs naturally in many plants, some invertebrate animal species (including nematodes, water fleas, some scorpions, aphids, some bees, some Phasmida and parasitic wasps) and a few vertebrates (such as some fish, amphibians, reptiles and very rarely birds). This type of reproduction has been induced artificially in a few species including fish and amphibians. So all you need to do is to invent one mad scientist/biologist who will figure out how to induce parthenogenesis in humans. [Answer] Look up whiptail lizards. These are all-female lizards that evolved from regular, two-sexed lizards, and experienced a mutation that allowed them to reproduce through parthenogenesis. However, they retain vestigial sex drives, and perform 'mock mating' that stimulates ovulation, typically switching between male and female roles. Yes, they are literally an all-female lesbian lizard species. Parthenogenesis has its downsides (not much genetic variation, so they are basically all clones descended from a single mutant) but in a sufficiently stable environment and with a particularly robust founding individual it could work. And if it could work in lizards, there's no reason it couldn't happen in humans\, especially if there's a genetic bottleneck involved. If there are a few mutations that occur over time, leading to differences in, say, hair color or personality, and some social mechanism celebrating diversity and ensuring that each population has members from each 'stock', you can even avoid the issue of them all looking identical - although there will still only be a handful of 'types', with each 'type' being genetic clones of each other. \EDIT: Actually, this isn't true. Although mammalian females have all the chromosomes needed to produce another female, mammalian egg cells are missing certain proteins that are transmitted by the sperm, so even if, through some mutation or another, the egg self-fertilized and activated, the embryo would never develop. You could probably pull it off with sufficiently advanced genetic engineering, though. [Answer] I don't think that your first two options are practical. All the examples of female creatures developing functional male organs occur pretty far from humans. This would not happen naturally with any likelihood. Also, it's not evident that the result would look female which is what I understand your goal to be. You could naturally have men evolve to look more womanly if there was some reason for it. Finding a reason might be difficult but is not impossible. The problem is that it would take more than your allotted two hundred generations to accomplish unless your reason was extremely good. The third option is quite practical in terms of the science. The question is why it would be true. I'm not convinced by your men becoming shameful option. If men's appearance changed it seems unlikely that it would cause them to become hidden. However, if men became rare (possibly through a disease that impacts men more than women), then women might hide their men from the other women to keep them safe. I would also suggest a fourth option of parthenogenesis. This seems likely to become possible within the next hundred years here, so it could happen in your world. Again, men are struck by some disease that kills them while women are simply carriers. Scientists then have to figure out how to mix the DNA from two women to produce a functioning fetus. The problem with this is that all reproduction would need help in this society. There would be no natural children. Note that cloning is also an option here if you prefer that to parthenogenesis. You could even have both. To summarize, the two most likely options as I see them require men to be either drastically reduced or eliminated by disease. In the first case, men might be hidden away because they are rare. In the second case, science would have to find a way to reproduce without men. [Answer] I could see it being a very big social movement. If we had gone down a path that didn't put women at a lower place, but raised them up. Many women want to be treated fairly like men (of course!), some act like men or dress like them to make it easier to be treated that way. What if it was reversed? We already have plenty of men and boys that dress and/or act feminine. (emo?!...) If it was a much larger social push it might be a lot more common thing, men might have electrolysis to remove facial hair etc. Of course this would likely be a 'temporary' social movement but it could be in full swing when contacted again [Answer] A biological warfare accident, retrovirus mutation, nanotechnology accident, bioengineering, or GMO accident could result in making human Y chromosomes inviable. Or GMO effects might result in Y chromosome effects being moved to other genes, which might (?) result in female traits developing even in men. Anything that results in men having female hormones in their system, and/or a lack of male hormones, will have some female rather than male traits occur in men, including breasts, no male-pattern baldness, and reduced facial/body hair, as well as altered behaviour (e.g. aggression and libido), and a wide range of other effects. You can get a lot of details on this by reading up on real-world transgendered people receiving hormones of the other gender. [Answer] The genders simply slowly drift into appearing more similar even though under the hood the remain basically the same. Do to cultural preference or genetic engineering, female breasts reduce in size and their hips narrow slightly. Males become shorter on average and slimmer, while baldness and body hair all but disappear. Long hair becomes fashionable to both genders as does androgynous dress - probably what we currently consider female; both because that's the direction you're looking for, as well as masking the person's silhouette. [Answer] Hermaphrodites are not an option. There is not a single documented genuine mammalian hermaphrodite in the world. Humans are mammals. Without genetic engineering it just won't happen. Feminizing the men could happen by mother's disapproving of male behavior and approving of female behavior, depending on that cultures definition of what behavior is male or female. Selective breeding would reinforce this. I don't see hiding the men away as an option without first feminizing the men. Men evolved to be big strong tough and aggressive. We go out and wack things with pointy sticks to eat. A lot of psychological manipulation would be needed from an early age to get the men to not notice that they are physically able to just ignore the commands. ]
[Question] [ First of all, I am tagging this with the [magic](/questions/tagged/magic "show questions tagged 'magic'") because this phenomena is not a result of something natural. What would happen to a whole forest region if a patch of desert magically appeared at its center? Below is an example of what I am trying to illustrate. Note: * The beige-coloured parts represents the desert that was magically displaced in the forest-y region * Whole forest = 25 mile radius * The climate is not transported * The desert is a Sand desert [![enter image description here](https://i.stack.imgur.com/HCiAD.jpg)](https://i.stack.imgur.com/HCiAD.jpg) Here is an image to illustrate the elevation. [![enter image description here](https://i.stack.imgur.com/sBXRE.png)](https://i.stack.imgur.com/sBXRE.png) As you can see in the image, it is like the center of the forest was cookie-cutted and then replaced with this patch of desert. And also, the elevation would be flat. *Question: What would happen to the forest (by forest, I mean the forest with the desert in it)* within 1 year and within 5 years? I am mostly curious whether the forest will turn into a desert or the desert will turn into a forest. With my proposition, let us assume that the [magic](/questions/tagged/magic "show questions tagged 'magic'") only applies to the magical translocation of the said desert and nothing else. The forest is just a normal forest. Thank you. EDIT: This is a little off-topic, but this ought to help you guys for generating maps. If anyone is interested, this is the [tool](https://www.redblobgames.com/maps/mapgen2/) I used to generate this map. This [tweet](https://twitter.com/ptychomancer/status/980968298002006016?s=20) also contains excellent resources for generating something like this. [Answer] What happens largely depends on the climate-conditions it is set in. Most important question: How does this affect Rainfall. You cut back the Mountain, which could result in less rain because of the missing elevation. If the cross section is to scale, you cut back about 2.5 miles of mountain*, which is a lot. It will considerably lessen the rainfall and allow for faster winds on the leewards side. [See how this works here](https://sciencing.com/do-mountains-affect-precipitation-8691099.html) You also eliminated the trees, so the days will become hotter and water will evaporate faster. Trees reflect infra-red and protect the humid air below them from getting blown away. Some historic examples of islands suggest that deforestation can lead to a change in local climate to a more barren one. [See Easter Islands for example](https://rainforests.mongabay.com/09easter_island.htm) Sand heats up much faster in the daylight and cools of more quickly in the night. The turbulence by the hot air from the desert could result in some local thunderstorms. [Similar to urban heat island effect](https://en.wikipedia.org/wiki/Urban_heat_island#Other_impacts_on_weather_and_climate) Then it depends how windy the whole region is, and if there is a main direction the wind is coming from. 1. Wandering dunes: Sand will probably get blown into the forest and could bury it all the way to the coast, in the main direction of the wind. See [Rubjerg Knude](https://en.wikipedia.org/wiki/Rubjerg_Knude_lighthouse) 2. Depending on rainfall, the vegetation will creep into the desert, or the desert will expand. 3. Lakes and streams will appear in the desert, providing some early oasis, if there is still sufficient rain. Also 1 Year is not a long time, you´d probably only have some strange weather and some new rivers. I tried to imagine 5 years with a dominant east wind: [![enter image description here](https://i.stack.imgur.com/Owy4d.jpg)](https://i.stack.imgur.com/Owy4d.jpg) [Answer] The desert will slowly be overgrown by the forest. Desert are created from a lack of rain and looking at the map, rain isn't an issue. Plants will start growing in from the edges and more hardy plants will pop up in the middle. Leaf litter will build up. Animals will move in and eventually everything will be as before. As for time frames, there is no scale on the map. Is it 12 square miles on an island or 12 million square miles on a continent? [Answer] I'm assuming this is an island in an ocean and not in an inland lake. Given that, there will probably be a fairly consistent wind pattern and it will have plenty of water in it. (Otherwise there would have been no pre-magic forest.) The picture shows a mountainous interior, but also seems to show the forest to be pretty uniform. That says that the original mountains were not very high. If the mountains had been higher, they would have cast a major rain shadow and the leeward side of the island would have been dry. (On the Big Island of Hawaii, the windward side gets as much as 20 feet of rain a year, while the leeward side has sections which get ten inches and look like the dryer parts of Wyoming.) (N.b., if the island was a lot larger and the desert correspondingly bigger, the lack of evaporation from the missing forest would have an effect, and would somewhat decrease rain downwind. At 25 miles this can probably be ignored.) Your picture shows sand "all the way down". This would have a profound impact on the post-magic development. Because the mountains were low, their removal would have little effect on the weather patterns. So we can expect the rain pattern would be about the same as it was pre-magic. The deep sand would greatly reduce the speed at which regrowth of forest takes place because there would be no water at all in the top layers -- rainfall would very quickly percolate downwards to the level of the water table which would probably not be that much higher than sea level -- it all depends on how impervious the deeper layers of earth under the original forest were. If the water drains away, it is nearly impossible for soil to develop because organic matter that gets blown in by the wind says dry and gets blown away again. (You see this in the Pumice Desert next Crater Lake in Oregon or in Desert of Maine.) So recovery would be slow. In fact, if* the border of forest was narrow enough, the deep sand would lower the water table under the forest and might actually kill off the forest. My gut feeling is that this would not happen with a ratio of forest to sand as shown. [Answer] This is actually a much more interesting question than it looks like on its face. So now we have two 'camps' warring against each other. Because of the apparent proportion of forest to desert, the immediate effect is going to be a drop off in the humidity levels of the remaining forest, as it lost its most humid portion. This is going to slow vegetation growth and mess with animal symbiosis something fierce. Likewise, the fact that the desert sands send hard rains flooding across its surface, and softer rains just sink deep in below where a tree could get it, it would take generations to build up enough tilth to sustain forest plants. So this sudden desert has a very good chance of messing up the existing forest. The answer? Eventually, this whole island is going to be savannah/grasslands. The forest animals are very likely to compete over suddenly scarce resources and die out, and those that are left are very likely to kill off most of the larger plants in a desperate attempt at survival. Grasses don't need complex ecosystems to maintain, and are likely to exist where the forest meets the ocean anyways. So slowly, the desert is colonized by grasses, and then the scraggly bits of what's left of the forest will be colonized too. [Answer] Let's start with the actual example of the artificially generated desert that exists in the real world, called [Błędowska Desert](https://en.wikipedia.org/wiki/B%C5%82%C4%99d%C3%B3w_Desert). There are some differences compared to your question but it can give you an idea what will happen since there is no change of the climate. As you can see now the dessert is slowly being grown over and that's what most likely will happen in your world's case. Since you do not change the elevation, the speed of this process most likely will be much faster since the conditions will be much more in favour of the flora restoration. So in 1 year the changes will be probably visible and in 5 year serious (for instance there'll be no longer purely-sand places), however most probably the forest will not be fully back in it's place. Also the increased amount of sand might change the type of initially dominating trees to those having more extensive roots system. ## EDIT I've missed the original forest line/elevation which means the processes of restoring the flora will be slow, especially initially. Also there are some springs since there are rivers starting in the affected area. We may expect those springs remain so the water supply remain provided, but the river beds will probably change (depending how deep the sand layer is). So the desert will be grown over from edges and plants will show in the areas most humid. Anyway changes within 5 years are going to be rather small and noticeable mostly in the areas where water can be found. In longer run (decades) the dessert will decay and eventually get completely overgrown. The rest of my answer remain fully valid. [Answer] As others said, it depends on weather conditions - maybe the forest will retake the land, maybe the desert will grow. One theory about Sahara desert for example is that the location was relatively fertile and live (savannah-like?) during Ancient Egyptian times, but considerable infestation by Roman legions who wiped out a patch of clean land (no trees - good visibility and protection from night raids) to secure a camp for several thousand people here and there and everywhere over several centuries, combined with not so much rainfall (slow regrowth) and frequent strong winds to carry away the rootless land and cover nearby (not yet cut down) live lands with dead sand, ended up with the huge desert we know today. ]
[Question] [ Say a time traveler ends up back in time and has earned the good graces of one of the nations' kings by sharing some of his future knowledge. Knowing that the printing press was an important milestone towards increased education and science he suggests the king commit his most skilled people towards trying to create one. Unfortunately the time traveler did not bring back any documentation on how the printing press was made, nor does he personally know much about the mechanical challenges involved in making one. All he knows is the general idea that removable letters can be locked in place to spell out words, then the machine can be turned by hand to automatically ink and press the letters to paper. At what point in history would the European world have sufficient mechanization skills to be able to build a functional printing press from this basic idea? In addition how much time, and trial-and-error, would it take for the king's chosen designers to perfect the design of a printing press if given such a general description of a printing press? For this question ignore any of the 'standard' time traveler problems, like altering history, concerns about language barriers, or being declared a heretic/witch etc. Though if there are concerns that would specifically apply to printing presses, like a belief that a king couldn't be convinced of the value of building one, or some practical reason a functional printing press would not prove as useful under this situation as it did in our own past, I'd be happy to hear about that. [Answer] 1. The printing press is not what Gutenberg invented. The printing press itself was known in Europe since the High Middle Ages at least, and in China even earlier. He did not invent movable type, which was also known. As for the "mechanization skills" needed -- printing was the last of the basic industries to be mechanized. Printing remained extremely labor-intensive up to the very end of the 17th century, and not extremely but still very labor-intensive to the end of the 18th. In the 15th, 16th and most of the 17th century a printing press looked something like this: [![Printing shop in 1568](https://upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Printer_in_1568-ce.png/640px-Printer_in_1568-ce.png)](https://commons.wikimedia.org/wiki/File:Printer_in_1568-ce.png) A printing shop in 1568. The press is on the right; note that it is a very crude press, with a vertical screw and huge manual winding handles. The man next to the press is applying ink to the printing form. The man next to him has just taken a freshly printed sheet off the form and is examining it and placing it on top of the previously printed sheets. Picture from the 16th century, [available on Wikimedia](https://commons.wikimedia.org/wiki/File:Printer_in_1568-ce.png). 2. Looking at how a printing press really looked like for the first three centuries of the history of printing, one would have to ask what exactly was the contribution of a jeweller? Glad you asked, because what Gutenberg invented was much more important that the press itself (which was already in use) and the idea of movable type (which had come and gone many times). He invented the [hand mould](https://en.wikipedia.org/wiki/Hand_mould), a simple yet crafty device used for making typographic letters (which are called "[sorts](https://en.wikipedia.org/wiki/Sort_(typesetting))" in typographic language). You see, the basic issue with the idea of printing with movable type was that the printer had to make many many As, many many Bs (but only about 1/10 as many as As), many many Cs and so on. As long as each letter had to be made individually this was basically so labor-intensive as to be uneconomical. Gutenberg, a jeweller by trade, came up with the following idea: * Make one hard-steel [letter punch](https://en.wikipedia.org/wiki/Punchcutting) or master letter of each sort: one uppercase A, one lowercase a, one B, one b and so on. Repeat for each type size you need. This is done by very highly skilled people, usually with jeweller training. * To make a batch of type (type was usually sold by weight, say 10 pounds of type, containing an empirically-determined mix of letters), use the hand mould. The hand mould is a rectangular steel tube, one end of which can be stopped with a replaceable mild steel block; take the master letter in hard steel, put it in the tube and give it a whack with a hammer: it will leave an exact negative impression on the mild steel stopper. This is called the [matrix](https://en.wikipedia.org/wiki/Matrix_(printing)). * Once the matrix (negative impression) has been made, melt a suitable amount of printer's alloy (an alloy of lead, antimony and tin, also invented by Gutenberg) and pour it in the tube; you will get a copy of the letter. Repeat and repeat and repeat until you have the desired amount of letters. Each of the sorts produced by this process looks like this:[![Diagram of a cast metal sort](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e9/Metal_type.svg/640px-Metal_type.svg.png)](https://commons.wikimedia.org/wiki/File:Metal_type.svg) Diagram of a cast metal sort. Public domain picture from Wikipedia. One may want to notice that this is a very very manual process. Printing in general remained a very very manual process up to the end of the 18th century, and was not truly automated until the end of the 19th. See the brief and not entirely misleading Wikipedia articles on [movable type](https://en.wikipedia.org/wiki/Movable_type) and the [history of Western typography](https://en.wikipedia.org/wiki/History_of_Western_typography). 3. The conclusion is that printing presses with movable type could be built any time since the end of the antiquity; all they really needed was: * Paper (because while printing on vellum is technically possible, and it is actually done for real, the cost of vellum would have been prohibitive); * Access to lead, antimony and tin (availble since the antiquity); and * Access to small amounts of hard steel (available for import from India through Damascus since the late antiquity). [Answer] I'm going to argue that the cultural aspects don't matter. Well they matter some. Books (or written pages) and literacy need to exist. But we're talking about a king here. If he decides to humor the funny man from the future, he doesn't need a reason (and whether or not he does so is a story problem, not a Worldbuilding problem). He just needs the funds, workpower, materials, and underlying technology. Let's assume that the king has available to him sufficient funds and skilled workers of all kinds. That's a pretty reasonable assumption for any kingdom not in crisis. So what materials and tech do we need and when in European history did they exist? ## Paper While you can have books made out of vellum (animal skin), a printing press works on paper. Vellum (or a less fine parchment) I suppose is possible (especially for a rich kingdom) but paper really is the way to go. > > Paper made out of plant like fibres was invented by the Chinese Cai > Lun, who in 105 AD mixed textile fibres and fibres from the bark of > the mulberry in water and produced sheets of paper from that. The > invention of paper was one of the reasons of the successes of early > China, through easier governing of the country. Archeological findings > have shown that paper made from plantlike fibres, were already used > from 140 to 87 BC. ([ref](https://en.wikibooks.org/wiki/Papermaking/History_of_paper)) > > > That doesn't help us though. The question is specific to Europe and Europe and China weren't trading at that point. > > The art of papermaking was first exported from China to Korea and > Japan around 610 AD. Arabic people have learned the papermaking > technique in the 8th century from Chinese, as is being told, from > Chinese people skilled in papermaking who were captured. The Arabic > people spread the knowledge during their military campaigns in the > North of Africa and the South of Europe. The first paper manufacturing > in Europe started in 1144 in Xativa (near Valencia) in Spain. The > first papermaking in countries in Europe, which were not controlled by > the Arabians, was in the 13th century in Italy and Spain, although the > usage of paper was already known in Europe since about 1100. A paper > mill in Fabriano (near Ascona) in Italy existed in 1276 (and still > exists nowadays). Around this time sizing paper with animal glue was > invented in Italy. The Germans had their first paper mill in 1389, > followed by the rest of Europe at the end of the 15th century. In > Belgium the first paper production was in Huy (Hoei) in 1405 and in > Holland in in Dordrecht in 1586. > > > So now it depends on where in Europe you are. If you're in a location with a paper mill, then it's easy. If you're somewhere that has regular trade with a paper mill location, that's also fine. Certainly trade routes were well established [by the early Medieval era](http://www.historyworld.net/wrldhis/PlainTextHistories.asp?ParagraphID=gpy), but there were [other trade routes](https://en.wikipedia.org/wiki/Amber_Road) as early as the 16th century BCE. So let's assume that the king could acquire enough paper for these needs by the 12th century (paper mill in Spain) and maybe a bit earlier since he'll know to ask for it. Can the kingdom manufacture paper? Maybe. It's a bit more complicated than it seems so someone who doesn't know how might not be of much help. But with some trial and error, it's doable. Certainly by the start of the Roman era and probably sooner. ## Ink This one is easier. > > The first man-made ink appeared in Egypt about 4,500 years ago and was > made from animal or vegetable charcoal (lampblack) mixed with glue. > ([ref](https://pubsapp.acs.org/cen/whatstuff/stuff/7646scit2.html)) > > > Ancient Rome had ink, Medieval Europe had ink (starting about 800 CE). So getting or even inventing a basic ink is pretty straightforward. Except... > > In the 15th century, a new type of ink had to be developed in Europe > for the printing press by Johannes Gutenberg...Gutenberg's dye was > indelible, oil-based, and made from the soot of lamps (lamp-black) > mixed with varnish and egg white. Two types of ink were prevalent > at the time: the Greek and Roman writing ink (soot, glue, and water) > and the 12th century variety composed of ferrous sulfate, gall, gum, > and water. Neither of these handwriting inks could adhere to > printing surfaces without creating blurs. Eventually an oily, > varnish-like ink made of soot, turpentine, and walnut oil was created > specifically for the printing press. ([ref](https://en.wikipedia.org/wiki/Ink)) > > > This makes the printing task much harder. Our time traveler probably hasn't a clue about different kinds of ink, let alone how to make them. Maybe trial and error from skilled chemists, alchemists, or other material science types of workers, will do the trick. Maybe not. The ingredients aren't hard to find; the problem is the recipe. Does this kill our timeline? Perhaps not. The question is about creating a printing press. Not successfully using one. ## Fine metalworking We need tiny type (they can be "large print" but that's still pretty small) made perfectly square. The upraised letters themselves have to be perfectly smooth and flat, with the rest of the metal type so uniform that they all fit together just so. And so they can be held fast with a frame such that none of them slip. > > Around 1450, Johannes Gutenberg introduced the metal movable-type > printing press in Europe, along with innovations in casting the type > based on a matrix and hand mould. The small number of alphabetic > characters needed for European languages was an important factor.[6](https://en.wikipedia.org/wiki/Ink) > Gutenberg was the first to create his type pieces from an alloy of > lead, tin, and antimony—and these materials remained standard for 550 > years. ([ref](https://en.wikipedia.org/wiki/Movable_type)) > > > The first moveable type printer (porcelain) comes from China in 1040 CE. The first metal one is from Korea in 1377. So this technology is not very old. Even wooden moveable type is from China in 1040. It just doesn't go back that far. [Stone molds for metalworking](https://smartartbox.com/blogs/smart-art-blog/history-of-mold-making-and-casting) were around as early as 3000 BCE. And better casting arrived in Egypt not long after. Ancient Egyptians were making metal wire, including ones fine enough to weave into cloth, in the second millennium BCE, along with many other advanced techniques, including alloys that would work for printing. The first iron working in Europe though was Ancient Greece [in the late 10th century BCE](https://en.wikipedia.org/wiki/Ferrous_metallurgy#Iron_Age_Europe). It took until the 8th century BCE to bring ironworking to Central Europe. And until 500 BCE for it to become common in Northern Europe, including Britain. While bronze working began in Europe in the early 3000's BCE, it took a thousand years or more to spread outside of the Mediterranean. Mostly it was used for weapons and tools and not for very fine work like would be needed for type. I think this is your sticking point. Yes, there was some fine metalworking available in Ancient times, even many centuries before the common era. But it was not consistent in the way we need. To get type before the Medieval era or so, the king would have to send someone to an area that could make the type, who would stay for the months necessary to oversee the project. ## The machine itself Eh. This is the easy part. Wood, some basic metal. It's a press. Presses are old hat. It just has to be made very carefully so it fits together just so. A perfectly flat surface with grooves or markings for the paper to fit. A hand roller to apply ink to the type after it's been fitted into the frame and attached to the machine. A press mechanism to bring the type frame down on the paper. Done. ## Conclusion I'm going to put this about 1000 years before the common era. The metalwork is the hardest part. It will likely be outsourced to Greece. But a set of several hundred letters, blanks, numbers, punctuation, etc, should last for many years. So who cares if it takes 2 years to acquire? In that time, they'll get a source of paper and find an ink recipe that doesn't smear. Building the frame should take a few months and can't really be completed until the type arrives, since it must fit exactly. Maybe a total of 3 years after the king says "sure, why the hell not?" [Answer] Simple (but probably wrong) answer: about the same time as the [Antikythera Mechanism](https://en.wikipedia.org/wiki/Antikythera_mechanism). Simple (but definitely unhelpful) answer: [early to mid 1400s](https://en.wikipedia.org/wiki/Printing_press#Economic_conditions_and_intellectual_climate). Long answer: I'd argue that the printing press isn't the critical thing. Moveable type dates back to 1800BCE on Crete, as demonstrated by the [Phaestos Disk](http://www.typeroom.eu/article/first-movable-type). [Block printing existed in China](https://en.wikipedia.org/wiki/History_of_printing_in_East_Asia) before the 8th century CE, and screw-presses existed in Asia and Europe for a good hundred years before Gutenberg made his particular contribution. It isn't clear when complex mechanical devcices could first be made, but the [Antikythera Mechanism](https://en.wikipedia.org/wiki/Antikythera_mechanism) is a pretty fancy bit of gear, and appears somewhere aroud the first century BCE. The problem is one of motivation. Your question shouldn't be "who could build a printing press" but rather "when would people be prepared to make printing presses to disseminate knowledge and educate the masses", because that's a whole other kettle of fish. Those ancient kings you're trying to pitch to? They'd probably wonder why on earth a peasant needed to know about mathematics and logic, cos it ain't gonna do much for their day to day lives. I'd be looking at persuading the church, not the state. Christian monasteries had things like [Scriptoria](https://en.wikipedia.org/wiki/Scriptorium) from ~500CE, where monks would copy books allowing knowledge to be (slightly) more reliably maintained and disseminated (even if it was largely for missionary purposes at the time). From my highly uneducated point of view, it looks like a monk named [Cassiodorus](https://en.wikipedia.org/wiki/Cassiodorus) popularised the idea of copying books, and his important work Institutiones which included discussion on the subject was finished around 550 or so. The poor schmucks who actually had to do the grunt work of copying would probably have killed for a mechanised way of doing so. The [Carolingian Renaissance](https://en.wikipedia.org/wiki/Carolingian_Renaissance#Scholarly_efforts) and formation of the Holy Roman Empire is probably when this sort of thing really took off, and that wasn't until the late 700s. Secular (you could probably also describe them as "professional") scribe services appeared not long before Gutenberg's press (relatively speaking), and this isn't a coincidence. Also, around the same era, you get [Medieval Universities](https://en.wikipedia.org/wiki/Medieval_university). Again, not a coincidence. The printing press facilitated a change, but the environment in which it appeared was already ripe for that change. Without that huge social and cultural foundation, it simply wouldn't have had the impact it did. This is a similar problem to all the other time-travel-technology questions; stuff never arose in a vacuum! [Answer] The prerequisites ([printing press](https://en.wikipedia.org/wiki/Printing_press), [movable type](https://en.wikipedia.org/wiki/Movable_type), metal casting, paper) were available in some form since antiquity. The enabling factor was most likely cultural: simple European alphabet and existence of critical mass of literate population (not only nobility, clergy and monks, but also townspeople). [Answer] Essentially, a printing press is a fancy set of stamps. Stamps have been in use since the 4th century, and printing was used in 8th century China already. More likely, the king would ask "Why would we want books and knowledge to be easily accessible?" [Answer] The Antikythera mechanism was probably made in 205 BC - but no later than 87 BC. [Images](https://www.google.com/search?q=antikythera+mechanism&source=lnms&tbm=isch&sa=X&ved=0ahUKEwixze-MkLviAhUp6nMBHXtEAY4Q_AUIDigB&biw=1800&bih=885) & [Wikipedia article](https://en.wikipedia.org/wiki/Antikythera_mechanism). * Wikipedia: "It is a complex clockwork mechanism composed of at least 30 meshing bronze gears. ... Detailed imaging of the mechanism suggests that it had 37 gear wheels enabling it to follow the movements of the Moon and the Sun through the zodiac, to predict eclipses and even to model the irregular orbit of the Moon, where the Moon's velocity is higher in its perigee than in its apogee. This motion was studied in the 2nd century BC by astronomer Hipparchus of Rhodes, and it is speculated that he may have been consulted in the machine's construction. It 'knocks a movable type printing press into a cocked hat'. Give the people who built it the basic concept and you'd have your printing press by lunchtime. (Or next week, at the latest). (OK - next year, but you get the idea). [![enter image description here](https://i.stack.imgur.com/Wkk8p.jpg)](https://i.stack.imgur.com/Wkk8p.jpg) ...........Functional model ...................... Operational diagram .......................... The original ]
[Question] [ Assuming that the world still uses melee weapons like swords and spears, has magic and medievalesque warfare tactics. They are a race of smart mice (they still look like mice, just that they can use armor, weapons and magic). And their opponents are a human army and kingdom (for whatever reason they want to destroy a kingdom (I don't know), maybe to get a lifetime supply of cheese?) * NO MUTATIONS. * LOW TECHNOLOGY (no, they can't build a tank and start shooting pea-sized shells). * Assuming that they can stand on two legs and hold a weapon with one 'hand'. For an idea on how they kind of look, they look like the mice that are in the mobile game War Tortoise. EDIT: Urh, I wasn't expecting the mice to to have a landslide victory actually, but I feel like it would be pretty easy to counter them once you know of the them. Adding in magic would really just make them stupidly overpowered [mice who can cast stuff like poison needle and fireballs???] like they would just outright assassinate humans. Sry if they were any weird unexplained parts, this was my first question Nonetheless I'm gonna make that follow up question and thank you all for answering. [How would humans defend themselves against mice that are sentient and intelligent?](https://worldbuilding.stackexchange.com/questions/47216/how-would-humans-defend-themselves-against-mice-that-are-sentient-and-intelligen) [Answer] Forget armor, forget swords unless they're needles filled with venom. Such weapons don't work well at small scale and are utterly useless against any foe much larger than the mice themselves. Poison. The mice are going to need lots and lots of poison. Their big advantage is numbers. Mice are fully grown at 12 weeks and can reproduce 5-10 times a year with litters of 3-14 each. individual mice will be expendable in a battle for survival. They just need to be willing to sacrifice themselves for the sake of litter and nest. The humans will try to poison them but the mice can use this to their own advantage by simply stealing all the poison. Cats and dogs being a major threat but lacking intelligence can be targeted first. The mice could lace food with poison and drop it to the animals. Suicide mice may volunteer to throw themselves into the mouths of dogs after eating as much poison as they can. ordinary mice might routinely carry poison capsules on their person simply so that anything which snaps them up whole won't be eating anyone else ever again. Poison and disease would be powerful weapons with the mice destroying food reserves and contaminating wells but also open to the mice is the option of arson. Fire. Fire would be a terrible ally of the mice. Mice can enter almost any building, get almost anywhere and smart mice can pick their targets and coordinate. Imagine across an entire city at 3 in the morning suddenly 10,000 tiny bags of oil are ignited in every house with anything dry enough to burn. The kings guard rush to defend from an attacking horde but find nothing. Just people and animals fleeing while unnoticed a few mice flee beneath peoples feet. As the city becomes a firestorm the surviving mice flee through the sewers. Stealth The war with humans would rely on stealth. The mice are at the greatest advantage while the humans don't know they're fighting. The mice can sneak into almost any planning meeting, dig out almost any secret. If the humans became certain of the nature of the threat there are far more potent defenses they could mount against mice than would ever be used against ordinary dumb mice but if the mice could strike first with enough coordination they could destroy entire kingdoms in a day. Areas occupied by the mice are going to be notable for their absence of various predators since the intelligent mice would slaughter them one way or another just as humans wipe out any predators willing to kill humans. [Answer] Same tactics non-intelligent mice have been using to kill humans for millennia. 1. Attack the food supply. 2. Spread disease (black plague, aka Yersinia pestis). 3. Go after the young/infirm/elderly (infants in cribs, etc). Trying to conduct a stand up "war" with humans is futile, as humans will just employ rat catching dogs and cats to massacre them, no need for humans to do any fighting. So the mice will have to utilize extreme asymmetric warfare tactics. Do the humans know these intelligent mice exist? The mice, if they are literate, could easily "curse" the kingdom by destroying food and water supplies and leaving apocalyptic messages behind. Since they can infiltrate areas humans can not, humans will likely not have any "rational" explanation and will quickly default to a superstitious one, especially if the mice know enough about the human religion to exploit it. Combine that with deliberate spreading of disease (even just seeding their feces into food containers, wells, and silos will do the trick, they don't have to employ actual pathologic organisms) and targeting of the most vulnerable members of human society, the mice could easily destabilize the kingdom to the point where it collapses and people flee. Coordinated groups of tool using mice would be more effective at taking out lone cats and dogs, so those are really their most deadly opponent. Should it come to battle with a human, the mice can use needles smeared with feces to puncture the skin and let disease take over. Highly unlikely that they could overwhelm a human unless they could drop it to the ground and go after the throat or trap it in a confined area. Humans would most likely employ fire/poison against rodents, trying to kill them individually is virtually useless. Assuming that groups of intelligent mice are a known thing to humans, the humans may have better luck hiring a rival tribe of smart mice to kill the attacking smart mice, paying "protection cheese" if you will. Quite frankly, most medieval societies would probably vastly benefit from a controllable rodent population they pay off in return for secure homes and food storage. EDIT: I didn't address magic because you have left it very vague. Elaborate on the type of magic (DnD style, druidic, etc) and I can incorporate that. [Answer] Well, depending on a few details you don't specify, they could do a lot of damage. Mice are tiny and can find their way into pretty much anywhere if they have a mind to. We use poison and traps to keep them under control, but smart mice would easily avoid those. Thus, they would pose a significant threat to any group of people they decided to go up against. They could sneak into the larders and poison, or spoil the food. They could sneak up into bedrooms and assassinate key individuals in various inventive ways (setting up tripwires, stabbing them while they sleep, poisoning them, etc.) They could set fires, or set off powder magazines. Realistically they could assault a town and wreak terrible damage before anyone even realized they were there. I would imagine that cats would become very popular pets, but that the mice would develop ways in which to fight them as well. Humanity's defense at that point becomes magic. Wards against pests, magical bait which lures even the smartest mouse to its doom, etc. [Answer] > > their opponents are a human army and kingdom > > > Are the rats targeting only the royalty and their loyal army, or the entire kingdom along with its citizens etc.? If the former, an effective way would be to help any human attackers (enemy nations, rebellious nobles) to win over the targeted enemies. If there are parties discontent with the targets, the rats could foster more unrest and provoke a fight between the two sides. Then, sneak into armories to gnaw at their armor fastenings, saddles etc. Tunnel underneath the royal fort and citadel so that walls collapse, moats are drained (maybe into the inner area!) and generally make the defenses a shambles. Granaries would also be a prime target to cut off the human food supply while satiating the rat hordes. An army that can't ride horses or wear armor, unable to turtle up in good fortifications because those are wrecked, and short on rations - is going to be far easier to defeat by enemy armies. Now, this is assuming that the intelligent rats aren't able to make direct alliances with enemy countries and are working in the shadows. If that is not the case, then they could even setup an effective cooperation including providing valuable intel on troop movements and highly protected areas (which are likely to be places of refuge or treasure storage). [Answer] It's all about the swarm. Overwhelm them with numbers. Rats and mice are territorial, you either get one or the other. A rat will kill a lone mouse, but the mice mob the rats and attack from all sides. Mice can breed up to very large numbers very fast as any Australian grain farmer will tell you. This is a numbers game my zerglings, just numbers. [Answer] Wiring and other subtle sabotage would be a good target. Human with car? Chew wiring. Get into the exhaust or chew into pipework and plan to block the pipes or leave sooty deposits in the engine or pipework. Electrical devices? Chew, expose to rain, at a pinch chew the wirings and short them out as you die. Poison and product contamination are also workable - spread with paws and fur. Mice have numbers on their side, which makes kamikaze (in the broad sense of dying to do more harm) a workable approach. [Answer] Disease Simply crap in the humans' food. Rodents don't even need to be intelligent to kill lots of people that way. [Answer] Magic makes it easy. Cast a spell that has terrible effects on the much larger human beings but causes no problems for mice. Maybe it makes things heavier, or some dramatic thing that is good for the story. But just killing anything warm blooded and larger than a [stone](https://en.wikipedia.org/wiki/Stone_(unit)) would do. Just wouldn't be much of a novel if it were without interesting side effects and worked too well/too fast. [Answer] It would make no sense for either the mice or humans to arm themselves with swords and armor. Both sides would rely on agility and unconventional methods. The mice could leverage some form of catapult style weapon, perhaps with fire or a pencil sized poison dart as the payload. For inspiration, read up on the US experiments during WW2 when they considered unleashing swarms of bats fitted with tiny incendiary bombs against Japanese cities. That was to be the backup plan if the a-bomb project didn't pan out. <https://en.wikipedia.org/wiki/Bat_bomb> If possible, a good tactic would be to lure the humans into a slot canyon and attack from above. [Answer] Use weapons and tactics similar to those that humans use against elephants and whales. By the way, I once read that three sleeping elephants bled to death after rats gnawed the soles of their feet. So maybe the mice could simultaneously cut the throats and wrists of every human sleeping in the city. [Answer] Same way they did already. Use biological warfare. Rats/mice were the primary spreaders of the black death in the dark ages. They just need to spread it again. They need to use what there already well suited for. Spreading sickness and pecilence(sp?). Next they can just eat all our food stores. No need for weapons or magic at all [Answer] In short: not enough information given. Really, everything is possible by making up different kinds of magic. To me it seems like you already know how you want them to fight (namely in a medieval sword and fireball way). So what you actually need is not an answer to your question as you posed it, but you need to make up your mind about what capabilities you can give them without changing the outcome which you already have in mind. Only once you have that fixed you can continue and find the way for them to attack humans which benefits your story the most. [Answer] one thing that I recently learned about mice is that they are functional blind. We had mice in our backyard who showed no fear in coming out in the open when the cats were watching from the outdoor cage we keep them in. The mice would hide when pigeons would come to feed so shadows and swooping, fluttery sounds they could hear. But they did not realise the cats were watching, and would even come all the way down the garden and enter the cat run (big outdoor cage) without realising that would be a mistake. When I talked this over with my wife she said well of course! Mice are blind. They have very poor vision and do not reply on that sense for finding food or anything. So .. all of the other answers presume that mice can see what they are doing .. aiming weapons etc .. when they cannot. Just Sayin' ]
[Question] [ Reality check: Protagonists of my story have a scientific device of a peaceful purpose. Unfortunately, despite the peaceful purpose, activation of the device, as a side-effect releases about 100 kilotons equivalent of energy, mostly thermal. No radiation. They don't want to cause any harm. Absolutely no casualties, minimizing damage to property and wildlife. They are in Central Europe, specifically Poland. The time is spring of 2015. International travel with the device beyond borders of EU is problematic - while a rudimentary control by police or border guards between EU countries would reveal a neatly packed ton of bathroom tiles on a first glance, and a fancy artistic mosaic on the second glance, if they start poking e.g. scratching samples to test whether it doesn't contain drugs, they will damage it (and won't find anything illegal). The device requires open sky above to operate, so unfortunately underground is not really an option. They've recently obtained a lot of money (legally), but they have no influences, no friends in position of power, nothing of out of ordinary - other than access to the non-Earth knowledge. Knowledge, which allowed both gambling the markets in ways current economists can't dream of [AND proving validity of these methods to [SEC](https://en.wikipedia.org/wiki/U.S._Securities_and_Exchange_Commission), so the illegal insider trading charges were dropped], and construction of the device, using commonly available (if expensive) human technology. They operate secretly - if the scope of the knowledge became common, people would kill for it, either to get it or to bury it forever... In my story their choice was to take it to the sea, in a barge pulled by a tugboat. The Baltic Sea is pretty crowded, but finding a 20-km diameter area without any vessel, off common routes is quite viable. Dropping off the barge there, moving the tugboat by 10 km, activating the device remotely. Of course that would get them in trouble with the law, but after the device is activated that becomes a trivial issue. All they need is to survive several next days and their problems would solve themselves. So, my questions: * Is my sea option viable? Did I miss something that would make it not work? * Did I miss any simpler, safer, easier solutions? [Answer] Svalbard Archipelago, [Nordaustlandet](http://en.wikipedia.org/wiki/Nordaustlandet) island. 14,443 square kilometres, uninhabited, mostly barren and covered in the Austfonna glacier, demilitarized by treaty, so no pesky soldiers to get in your face. It's so remote that the German outpost there during WWII took months to find out the rest of the Nazi forces had surrendered. ![enter image description here](https://i.stack.imgur.com/dziGH.png)![enter image description here](https://i.stack.imgur.com/1GSeR.png) While Norway is not technically an EU member state, it is part of the [Schengen Area](http://en.wikipedia.org/wiki/Schengen_Area), so in effect passport-less travel for your Polish citizens. When you get to Longyearbyen, talk to the Governor, Odd Olsen Ingerø (he's a charming fellow), and get a few small boats and a few ATVs. Tell them it's a high-volume renewable energy experiment or something. Show them some grant application papers with EU stamps on them. I'm sure you'd find a few dozen people there who'd pitch in with transport, for a modest fee. If they don't cooperate, talk to the local Russians. Bring plenty of good Polish vodka. US and Russian satellites will probably capture the thermal flash, although, with a bit of effort, you could time it to their flight patterns looking for a gap. The seismic stations will likely still capture it, but since Svalbard is part of the High Arctic Large Igneous Province, earthquakes and even a bit of volcanism are expected. Note that a sudden input of 100kt TNT equivalent ($ \approx 5\times10^{14}J$) of energy into the atmosphere and nearby ground will create a blast shockwave, regardless of the source of the energy. Perhaps keep that in mind for story purposes. [Answer] Here's a [link to a nuke simulator](http://nuclearsecrecy.com/nukemap/?&kt=100&lat=56.0782451&lng=18.7275598&hob_opt=2&hob_psi=5&hob_ft=20&ff=50&psi=&rem=&therm=_3rd-100,_3rd-50,_2nd-50,_1st-50,_noharm-100,35&zm=8). There will be more heat damage and less over pressure in this case. But I would worry more about the potential tsunami effect of releasing this amount of heat into the water. The water turns to steam and expands, a lot of the expansion will go upwards, but some will move water horizontally. The coasts of the Baltic States and Poland are generally low, so a tsunami could go far inland, causing lots of damage. And detonating 100 kt on the front porch of the Russian military base in Kaliningrad could make them a bit excited. In a bad way. The Atlantic ocean would be a better idea. You would still kill a lot of fish, but the other effects would not be as serious. I guess the inhabitants of western Ireland, Scotland, Norway etc are more used to high waves from storms. [Answer] If you want to stay close to home, find an open-pit mine or an old quarry. 100kT isn't that much if it's surrounded by a lot of earth, the pit would focus all the thermal energy up. Check airlines and the ISS orbital schedule before pressing the button. If you want to leave, there are no effective border controls between Poland and Germany anymore, so just drive west. Getting a boat in the Med or Portugal should be easy, then there's a great big ocean available. [Answer] If you want a remote, low population density area within the EU your best bet is Northern Sweden or Finland during winter. It is not really uninhabited but in the far north the land is uneven enough that you should be able to find a valley that has no one else in it and is large enough to contain the explosion. And transport from Poland should be manageable, the road network is fairly good, sea transport is available even during winter. The main issue would be the last leg over tundra to the final location. Vehicles are available, but it would leave a paper trail. [Answer] How about an airburst over water, and avoiding aircraft so probably at night, over the North Sea (if that's European enough)? I think the Baltic sea makes sense. Buy a boat on the north coast of Poland, and a truck. To get it airborn to reduce damage to marine life and ships, I would suggest a large hot-air or helium balloon, though this greatly increases your required boat space, but as you are wealthy, you can buy another boat or two. The technicalities of how much sky clearance overhead, and how much time your device takes to operate, may pose an engineering problem, but it sounds like you have ample engineering abilities. A donut-shaped balloon or series of balloons attached to a framework that leaves an open-air center would be possible, if clumsy. If that's not enough overhead clearance, you could use a combustible fabric for the balloon, and have it burst into flame at the right altitude, IF your device can do what it needs to do while in freefall, before falling too far. [Answer] Try Siberia, concretely the place where the Tunguska event was. As per Wikipedia (<https://en.wikipedia.org/wiki/Tunguska_event>) it was practically tested to withstand up to 10-15 MT. Or your hero could not travel to Russia because of the US/EU sanctions? :-) [Answer] Lapland(northern Finland). not impossible to find 20km with nobody in it. have them rent a helicopter with thermal imaging to confirm. roughly that there's no gold diggers. inside schengen, though you might get checked at borders for contraband. you can drive from poland to lapland too, without taking ferries or such. also due to the hilly, but not steep hills, nature of Lapland you could find a large enclosed area to perform the task in to contain the explosion. [Answer] A derelict oil rig is what you are looking for. At least one has burnt up and left something standing that may still be there. There may be sea forts in the north sea that are far enough away and if you put it higher you get less tidal wave. The barge proposal is still most likely to succeed. A new idea occurred to me. It might be a cool idea to tow it to the edge of the polar ice sheet in mid winter and retreat with the tugboat ahead of the ice formation. You could add some very noisy sonar systems (decoys) and announce you are doing underwater "sonar Doppler mapping and measurements" over winter and can people please stay away for 20km including subs that do not want to be detected. It might be the best way to have all civilians warned about the situation and the military desirous of staying away. The ice sheet should dampen any tidal wave and you would have a way to watch out for the curious coming from the sea side as you fall back. EDIT: Saw this question on my profile and had a thought that perhaps someone has already researched the question. Sure enough there was a Wikipedia page about the [least inhabited regions](https://en.wikipedia.org/wiki/List_of_uninhabited_regions). This would be a good starting point and the source material might have good pointers. As mentioned in another answer Lapland seems like a good place to focus on. [Answer] Nowhere? I think transporting the device elsewhere is much more viable. 100 kt is quite a lot if they really want to harm nobody. Does the thermal pulse come with a flash? That barge location might blow a small aircraft out of the sky, or hurt a surfer, or a sailing yacht. If there was a sufficiently empty area, odds are that it is a nature preserve. Could you be sure that there are no bird watchers you've missed? Last but not least, NATO and Russia would go frantic. Not a good thing given the recent tensions. How much would you bet that Sweden really has no nuclear program? [Answer] If you don't care about wildlife and destroying the site of many spaghetti westerns, the [Tabernas Desert](https://en.wikipedia.org/wiki/Tabernas_Desert) is probably one of the most sparsely populated areas in mainland Europe. [Answer] If you want to avoid going out to sea, [this nuke simulator](http://nuclearsecrecy.com/nukemap/) estimates a 100kt ground detonation wouldn't kill anyone and would only injure about 10 people if performed in a mountainous national park, like the ones in [Romania](http://nuclearsecrecy.com/nukemap/?&kt=100&lat=45.2781256&lng=22.581701&airburst=0&hob_ft=0&casualties=1&ff=50&psi=&rem=&therm=_3rd-100,_3rd-50,_2nd-50,_1st-50,_noharm-100,35&fatalities=3&injuries=12&psi_1=34&zm=12) and [Slovakia](http://nuclearsecrecy.com/nukemap/?&kt=100&lat=49.2197068&lng=20.0665185&airburst=0&hob_ft=0&casualties=1&ff=50&psi=&rem=&therm=_3rd-100,_3rd-50,_2nd-50,_1st-50,_noharm-100,35&fatalities=0&injuries=8&psi_1=27&zm=12) - or even [Scotland](http://nuclearsecrecy.com/nukemap/?&airburst=0&psi=&rem=&therm=_3rd-100,_3rd-50,_2nd-50,_1st-50,_noharm-100,35&casualties=1&ff=50&linked=1&kt=100&lat=56.9396195&lng=-3.8486579&hob_ft=0&fatalities=0&injuries=0&psi_1=0&zm=11). You could find a road running through some winding valley in the mountain region; stage vehicle accidents at each end of the road so you had the road to yourself; and use the device there. You might be able to get the number of injuries down zero by reserving all the rooms in local hotels and triggering at night. For the purposes of fiction, you could also say the mountains and turns in the winding valley absorb most of the direct thermal radiation going out at low angles. Obviously there will be serious damage to the valley, and people are quite sentimental about national parks, but it would avoid needing a boat and it could get your border crossings right down. [Answer] I don't think your barge/tugboat option works--barges are for calm waters, not the open sea. You need something more oceangoing to take it far enough out. I don't think you need that, though--simply charter an oceangoing vessel that either has or could support a crane big enough to lower it into the water. A collection of drums can provided the needed floatation while the ship backs off. As for safety--"Notice to airmen and mariners: At xx/xx/xx xx:xx at xx° xx' xx" N xx° xx' xx" W we are going to engage in a high energy physics experiment. Successful operation of this device will as a side effect liberate approximately 420PJ of thermal energy. This is not a nuclear device and it will not release radioactivity." I would put the energy in Joules rather than kilotons to stress the scientific nature rather than the potential military nature. Of course the nuclear powers are still going to go ape--scientific or not this is obviously a possible alternate means of building WMD. ]
[Question] [ Wild animals like wolves, lions and bears rarely attack people. They behave as though they know humans are dangerous and generally best avoided. Imagine a group of people traveling sideways in time, to a world that resembles Earth as it would have been had humans never evolved. Thus, the familiar species of wild animals are present, differing from those of our world only in having never been exposed to humans. How much more dangerous would they be? I can think of three possibilities: 1. The knowledge 'humans are dangerous, do not try to eat' is instinctive. Then the animals would be extremely dangerous for many generations until enough of them have been shot to evolve that instinct. 2. The knowledge is somehow learned. I don't quite see how this could be learned in the life of an individual animal, but if it is, then by hypothesis it could be learned quickly by the animals of the other world. 3. I've got it the wrong way round. Predators don't use the algorithm 'hunt anything that moves unless you know it's dangerous', they use the algorithm 'avoid unless you know it's safe'. In the absence of positive identification of humans as safe, the animals of the other world would avoid humans just like the ones of our world. Which of these is the case? Or is there something else I am missing? [Answer] ## All of these are true, so it depends on the animal. First, you have a lot more to worry about than predators; herbivores are often more dangerous than carnivores. Carnivores may hunt you when they are hungry, while herbivores may attack you for just being too close in case you are a predator. Hippo are more likely to kill you than a lion. An elephant in musth will kill you because you are there. Animals with young are particularly prone to this. Of course this is not all herbivores but most of the larger ones. For predators, it depends on the predator. Large ambush predators like crocodiles are often not that picky; strange food is food, because they rely on ambush they have less opportunity to investigate prey. This is the predator that will be most dangerous to your people, because they don't know what signs to look for. Most other predators tend to investigate new things before trying to eat them; some of them of course will conclude you are food. Humans are large enough that most predators default to seeing humans as a potential risk to hunt, so spend a lot of time investigating. But some predators are large enough this is not the case; things like polar bears and tigers are large enough they have to learn humans are dangerous. The bigger a predator is compared to a human the more likely it will decide you are worth eating without much investigation. A t-rex, just like a large shark, might nibble just to check, but a human may not survive the nibble. Humans have the double edged sword that we look bigger than we are, which makes animals wary, but predators and herbivores react differently when wary. Predators avoid, while herbivores may default to "drive it away". These are behaviors that evolved over and over again in the animal kingdoms, often with no human contact whatsoever. There is every reason to believe these are the behavioral patterns you will see on another planet. [Answer] It can be any of them, depending on the environment where the animal is grown and the animal's own behavior. Take for example the dodo: living in an environment with no predators, it didn't have the flee instinct, thus it was easy to capture. So easy that it got extinct. Or the pigeons which are being eaten by catfishes, not being used to avoid threats coming from underwater. On the other hand, curiosity might lead the animal to investigate what that funny, fur-less and two legged beast is. For a predator that usually means try to give it a bite. That's what most of the sharks do when seeing a surfer or a sub. Also note that for a predator approaching an unknown being, the being starting to run away usually triggers the hunt instinct. And it takes a lot of cool to have a beast the size of a lion or a bear sniffing around you and not flying away. [Answer] Generally Option C As far as predator go, the "hunt" kind (all of the big carnivores on earth atm)are naturally fairly cautious. They don't kill from a distance, they don't catch things in traps which incapacitate them. They have to get Up Close and in harm's way. There's a chance prey could hurt them back, and getting hurt can be a death sentence even if they make the kill. So their basic reaction to anything initially is to be very cautious about it. Now how long they stay cautious depends on the species and the animal. Lions, for example, will get over that shyness fairly quickly if it's just a single weird thing. (think vids of lions meeting drones or RC vehicles for the first time) They know they're in a group of other apex predators who will, to some extent, take care of them if they're injured, so they're more willing to test out new things. Solitary hunters like Leopards are far more risk adverse because they know if they get hurt they're on their own. Of course there are things humans could do to "give the game away" as it were. Running in panic can trigger chase responses, then the thing finds out the human is a squishy frail bag of food and the jig is up. A predator like a web-building spider or an ant lion is also pretty "grab first, ask questions not-at-all" which is likely based on their hunting style. So if you had a thing big enough to eat humans that makes webs that catch humans it likely wouldn't think twice of eating one in its web. For herbivores things are much more complicated and again depends on the animal. For instance if you ran across a gazelle who'd never met a human it's reaction once you got close enough would be "Flee in panic." But if you got close to, say, a Water Buffalo or Hippo it's reaction wouldn't vary from what it is now. Which is generally "Trample/gore/bite to death." Basically if an herbivore would get aggressive when hunted it'll get aggressive towards an unknown human which gets too close. "Too Close" bye the bye, is also fairly random and will depend on how the herbivore is hunted and by what. Is fairly slow and lives in the open? You might trigger the fight-or-flight reaction from further away than something which is lots faster than everything which hunts it. All of the above are, naturally, size-dependent. A 20ft carnosaur of some sort wouldn't think you're a threat at all, and chomp on you just to see what you tasted like. A 50ft carnosaur might ignore you entirely as being too small to be worth the bother. Meanwhile a 50ft herbivorous dino might trample you to death, because you're about the same size as the raptors which hunt the herbivore in packs. Then again, if the herbivore is only hunted by things 20ft tall or bigger it might just ignore you until you actively annoyed it. [Answer] Very There are two cases of predators in the modern world that have no natural fear of humans and well-documented interactions with people: polar bears in the high arctic and oceanic whitetip sharks in the open ocean. People have reported similar encounters with both. With polar bears, polar bears are known to walk towards human activity, wander through settlements in the far north with no fear, and even try to knock over tour busses in the arctic to try and get at the humans inside. [But you don't have to take my word for it, here's a YouTube video of a wildlife photographer nearly getting eaten by polar bears, only being protected by a very strong acrylic cage.](https://www.youtube.com/watch?v=BIql1ZpHovs) Polar bears often aren't afraid of the sound of gunfire and don't see humans as dangerous, they see them as food. Oceanic whitetips are similar. Far out in the ocean, they rarely encounter human activity and hence most don't have much of an innate reaction to humans. They live in an environment with little natural food and as a result they are often hungry all the time and always on the lookout for new food. Oceanic whitetips are insatiably curious, and studies have actually found they're drawn towards sounds of human activity, such as those made when a ship sinks, because they exhibit curiosity towards any novel stimuli in their environment. This is why oceanic whitetips are the number one threat to shipwreck survivors out of any marine animal. Survivors of oceanic whitetip attacks will note that nothing really drives them off. You can punch them, hit them in the gills, and it won't convince them that you're not a worthwhile target. They'll just circle back around and wait for you to weaken enough that they try again. The only real way to get away from an oceanic whitetip is to get out of the area. The thing that most of the other answers don't point out is that while predators aren't naturally bloodthirsty, they're naturally curious. Predators are highly opportunistic, and as a result they're always interested in a new opportunity that might bring them something to eat. Humans are the same way, it's the whole "can't look away from a car crash" phenomenon. If a stimulus isn't immediately threatening, predators will often investigate it to see what it is. Deviating from the routine is potentially a huge benefit if the animal learns of a new food source it can exploit (this is how man-eating lions, tigers, and bears start). And the way many predators investigate something interesting is with their mouth. In your situation you would probably have predators investigating the novel humans in their environment out of sheer curiosity if nothing else. Without a fear of humans they won't be conditioned to avoid people. Eventually a predator, most likely a young male or some other individual who are prone to taking risks, would likely eventually try to take a bite out of humans. And if that predator isn't killed or harmed the predators would quickly learn that humans are easy prey. There are cases among large predators IRL where predators learn which prey items are good to eat and how to catch them by watching each other. The good news is that any real defense would drive the predators off. A predator won't try to attack someone if you figuratively bop their nose hard enough unless they are really starving, and having potential prey that is strange and can bite back is enough to make a predator decide to go bother someone else. [Answer] We are finding in much of Canada with the decrease in hunting and general firearm use that bear and cougar are losing their fear of humans, and we are getting an increase in injury/death encounters. Case a few years ago with a cougar on the edge of the school grounds watch the kids play. I have done canoe trips where we had bears wander into camp. While wolves in North America seem to either leave people alone, (or they are smart enough to cover their predation...) in Europe they have a grimmer reputation. As others have mentioned polar bears actively hunt people. That said, Medieval Europe was characterized by far more fear of predators than actual predation. This came up about a week ago (~apr 20 ) on reddit's /r/AskHistorians. The fear was much greater than the reality. Larger predators tend to cautious about things that are strange. This can change if hungry, or you smell interesting. The more different you are, the more likely they are to give you room. Size ratio is also critical: lone predators tend to prey on animals smaller than they are. To hunt animals larger than you are requires group effort. Wolf packs are larger where they prey on moose than where they prey on whitetail deer. Polar bear and grizzly are enough larger that we don't intimidate them. Also, they are less likely to be cowed by our standing posture as they can also stand. (To a coyote, a human is much taller, hence larger) In places where wolf are hybridizing with coyote we are getting "coywolfs" which are intermediate in size between the two species. They seem to have the coyote's comfort levels of living near humans, are better able to treat medium sized dogs as 'lunch'. At this point they don't seem to have the wolfish pack structure. If you want an interesting sidelight in an urban story, picture a hybrid with wolf smarts and pack stucture, and coyote's 'just at the edge of accurate rifle shot' proximity to humans. Could make the cityscape more interesting. Small animals are more likely to attack with a 'nothing to lose' attitude. One trapper I know said the only time he's ever been attacked was by a muskrat. Herd animals are dangerous just because you can get in the way. Having a hundred zebra or buffalo running toward you can ruin your morning. Large herbivores are dangerous. Rhino and Hippo are cases in point in Africa. Many animals during the mating season are more likely to see you as a threat. Moose are have a rep for aggression when in rut. Herbivores learn quickly. Look up what the ecological impact on both deer and general riparian ecology was from the re-introduction of wolves into Yellowstone. Consider: Look how fast dogs learn things. Admittedly we've been breeding dogs that pay attention to human body and voice. [Answer] The algorithm animals use is less based on fitting objects into a formal ontology the way we do ("this one is a human, that one is a gazelle"), and a lot more based on salient features that are being perceived in the moment. When it comes to differentiating between danger/prey/not-interesting, the most important feature seems to be size. Other important ones are pattern of movement, sound and smell. There are sometimes additional highly-specific signals that can elicit specific behavior (example for instinctive ones: the red spot on a gull's beak, example for learned ones: a command for a trained dog), but these are species-specific and won't bring you further here. Ontology-based learning does happen (e.g. once a predator has been wounded by a porcupine, it learns to avoid all porcupines), but I have the impression that the perception-based behavior is usually more dominant for animals. For example, my cat has learned very well that the string on her rod toy is totally uninteresting once caught. Nevertheless, as soon as I wiggle it in front of her, she cannot help but go into a hunting mode. It is even observable how she is not so much using her intellect to decide "now I will play with this toy", but how her autonomous nervous system visibly drives her body, from changing her pupil dilation, up to the typical haunch twitches. So, it is not especially important that the animals have never seen a human. As soon as they perceive the human, the features observed in this perception will guide their behavior. If humans are of the "proper" size, they can be attacked for two reasons, either because they resemble prey (again observable in house cats, they prey-attack anything in the size range of a mouse), or because they resemble a danger to be driven away (typical in e.g. swans attacking kayakers - but note that the reaction of a Baltic seal to a kayaker is panic, again because of the size, they are rather undaunted by larger and noisier motor boats). The behavior of the animal will depend not only on what it perceives, but also on the context of the encounter. There is the "aggro radius" mentioned in other answers, its size depending not only on species, but also on the lay of the terrain, the personality on the individual animal, and on its current emotional state. Other factors matter too - meeting a lion pride at dawn, when it is looking for prey, is different from meeting it at noon, when it is holding its digestion break. Getting to know humans will get animals to learn behavior in some very specific ways, which won't have that much influence on being attacked in general. The closest would be if a lion pride learned to specialize in humans - they are not indiscriminate, each pride has its favorite pray animal, and the knowledge how to hunt for that specific animal is passed down from the adult lionesses to the young ones. The more common examples are the ones where it changes the animal's chance of survival - if you have an animal species which would behave neutral to a human-sized (or a boat-sized!) animal approaching them, and thus becomes easily slaughtered by an expedition of humans newly arrived in its territory, or hunted animals learning that humans are dangerous at distances larger than what their instinct tells them. Also, there are of course the cases of taming animals, making the behavior of that individual animal change drastically, although in the long run, you will still have instances when the animal chooses an otherwise suppressed behavior from its repertoire, that's how zoo keepers or circus trainers get injured by big animals. [Answer] ## Your World Will be Much More Hostile Towards Humans Any animals that humans have been effective at killing in large numbers at some point in the past have evolved to naturaly fear us. Meaning the first time they see a human, they will typically run away or hide. This includes most species of bears, canines, felines, crocodilians, ungulates, and other primates. This is because after generations of natural selection, all living members of these species come from ancestors who thanks to genetic drift naturally avoided humans. Basically, they feel the same way about us as we feel about snakes. Any members of these species who did not naturally avoid us were more likely to end up dead for even getting close to us; so, they could not pass on their genes to their modern descendants. To prove that genetic fear plays a big part in keeping modern humans safe, we need only look at what happens when our domestic animals (who don't fear us) start breeding with wild animals that do. One of the most common examples used are domestic dog/wolf hybrids. Nearly all pure-bred wolves fear humans even if they have never personally seen a human. However, when a wolf breeds with a domestic dog creating wild offspring, these offspring are known to be very likely to hunt humans. Because domestic dogs do not fear us, 1/2 of their offspring can only learn to fear humans through actual experience (meaning getting hurt trying to eat one of us). This makes them far more dangerous to humans; so, they often need to be put down. Another common issue with domestic hybrids comes in the form of wild pigs. Many breeds of wild pigs actually have a fair amount of domestic pig ancestry; so, many hunters consider them among the most dangerous of animals to hunt because they are more likely to choose to fight a human hunter instead of flee compared to other animals. There are also some other animals such those mentioned in [user2352714's](https://worldbuilding.stackexchange.com/a/198473/57832) answer that do not fear us; so, those animals are also good to use as behavioral models, but unlike user2352714's summation about why they do not fear us, it has more to do with evolution than individual learning. If it was just about learning, grizzly bears in remote enough of areas would feel just about as inclined to eat humans as polar bears are, but in reality they are not. So in your world, every animal that is big enough to even consider hunting/fighting a human is likely to do so. You will also have much larger populations of dangerous predators because they've never had to compete with humans for survival before. It will take many generations and a lot of dead animals (and humans) before the animals on your planet will develop any natural fear of humans. Until then, all you have is learned fear which is much less sustainable. [Answer] Closer to C, but not quite the way you have it. There isn't such a thing as a safe/not-safe species, but predators will always look for the safest circumstances to hunt. Basically looking for lunch that is: * Much smaller than the predator. * Alone or separate from it's group. * Obviously weakened by injury or illness. * Obviously weakened by being young. * Hampered by the environment (e.g. a large snake might try to get away if it saw you on land, but might attack in the water). * Unaware that the predator is there. One of the main differences is that large predators have been forced out (removed/killed) of many areas, which reduces how often they come into contact with humans who fit the above criteria. But if you go sideways to a world where that didn't happen, now you have grizzly bears in southern California and lions in Greece...and sending a kid out to play in the back yard alone is a bad idea. (It's also notable what animals won't be there. In North America there won't be red foxes in the western areas or coyotes on the east coast, and no pigs or horses at all.) [Answer] It is in the nature of animals to avoid getting hurt. This is why a swan can be "scared" away by a much smaller bird for example. If there is no reason to risk getting hurt, its better to avoid it. Remember that getting hurt is a massive problem outside of a society: infection, the energy to regenerate the wound and a lower chance to find more food or survive another encounter are all big reasons not to tempt getting hurt if you dont have to. The template of a predator has several key factors, such as eyes that are able to focus on the same spot in front of them to judge distance. Prey like a cow for example has eyes on the sides if their heads so they can see movement much more to their sides and almost behind them. If a predator recognizes another predator it needs to make a decision: is this food or is it dangerous enough that eating it might hurt me and my chances of getting the next meal. (I'm ignoring animals that have evolved to specifically eat certain predators here). Ofcourse a predator can always decide: I think I might starve if I dont eat quickly and you look weak enough, so I'll risk it today. There's also other animals that will happily attack humans. Hippo's are extremely territorial and wouldnt care if they've never seen you before, they'll come out and brutalize you if you dont watchout. Honeybadgers have similarly evolved to make other creatures afraid of it. Its hyper-agressiveness helps other creatures learn to avoid it. If a human got close, it would not hesitate. Similar for insects. Tl, dr: yes tons of creatures would have no problems attacking humans for a number of reasons. Their only advantage is that no animals have learned to specifically target humans as prey, but predators can learn to eat them if humams "let" them. [Answer] I note that a world without humans would not necessarily be a world without people. There are numerous species of mammals with intelligence ranges which might possibly overlapp considerably with that of humans,andwho might possibly deserve to be considered people. I note that before the evolution of genus Homo, the supreme beings onland were members of the orber Proboscidea, elephants and their relatives. There were proposcideans on every continent escept for Antarcticaand Australia for many millions of years before humans arrived. As late as about 13,000 thousand years ago there were over 15 species of proboscideans distributed over the world, from cold tundra to the tropics, from lush jungles to barren deserts, which are now extinct. And they may have had intelligence levels comprable to that of humans. So humans who travel sideways in time to an alternate universe where humans never evolved might find that in every environment the dominent species is a proboscidean one. ]
[Question] [ One thing that a few science fiction films seem to get wrong: it is extremely unlikely for two civilizations to evolve completely independently and yet be within a few hundred years of each other technologically when they make contact. They are more likely to be millions or billions of years apart. Could this be made more likely by some large-scale catastrophe that affects both star systems, causing mass extinctions in both at the same time, or by some other means? I was thinking of two stars, say 5 to 20 light years apart. Planetary life emerged in both at roughly the same time in terms of billions of years - still not very likely but possible. Then both stars drift through the same cloud of interstellar debris, or pass close to the same massive object or other star (maybe each other?) - this causes a mass extinction in both star systems (still no civilization). At that time, maybe the lifeforms at star A were more advanced biologically by millions of years than at star B, but the mass extinction brings both down to the same level. Could events like that, or something else, synchronize the development of civilizations at different stars so that they are at a similar technological level (within about 300 years)? More specifically, could one of those planets be Earth? [Answer] Evolution is an essentially random, undirected process, so even if you synchronize things with a planet-wide extinction, it seems extremely unlikely that both planets would evolve intelligent life at the same time after that (or that both planets would evolve intelligent life at all since evolution doesn't have goals). So, instead of trying to mess with the starting conditions, what if we change the ending conditions: What if there's an incredibly difficult piece of science or technology that you need to advance significantly beyond where we are now? So, one species evolves on one planet, reaches approximately our current tech level and then stagnates for a few tens (or hundreds) of millions of years. Then another species evolves on a nearby planet. Maybe the ability to contact the nearby planet leads to a massive breakthrough for both species, leading to interstellar travel and a giant leap in understanding of physics. This also sets you up with nicely contrasting cultures: The older species has had hundreds of millions of years to perfect their technology, so everything we can do, they can do much better.. but they probably hit the pinnacle of technology a long time ago and haven't needed scientists for millions of years. The younger species is still behind the older one technologically, but has a strong culture of science, engineering, and novelty and will likely catch up quickly, and perhaps come up with less predictable tactics. [Answer] > > Could events like that, or something else, synchronize the development of civilizations at different stars so that they are at a similar technological level (within about 300 years)? > > > The well-trod trope of humans being "seeded" on the planet by an advanced civilization is the first thing that comes to mind that would lead to this sort of behavior, though might not be as sufficiently independent as you'd like. Also: * The advanced civilization could "meddle" in affairs to speed or slow technological advancement to keep the two close. * If the seeding was done ubiquitously, the odds that some pair of civilizations remain at parity is much more likely due to the [birthday paradox](http://en.wikipedia.org/wiki/Birthday_problem). According to [this link](http://www.solstation.com/stars/s20ly.htm), there are ~17 stars in 20ly that possibly have habitable worlds. If you were in a more populous region of space, or expanded your radius, it would be even more common. (note that this applies to non-seeded life evolving as well). * There's also the (somewhat) well-trod trope of a colonization gone wrong. In this scenario the "advanced" civilization doing the seeding is the same as the developing one. Since there are likely ruins (if only a ship) it's a much shorter path from subsistence to inter-planetary discovery. [Answer] The odds of two separate planets developing at the rate are essentially zero. Time is bigger than space. Two sentient species would have to evolve within few hundred thousand years of each other just to be able to recognize the other as sentient. Multicellular life has been on earth for billion years. If you seeded two identical planets with multicellular life at the exact same time, and it took roughly a billion years for sentients to evolve, the sentient species would have evolve within a 0.001% of the total span of multicellular life for both to be sentient at the same time. Technology equilibrium is even more impossible. Look at earth's history. At any given time, one area has been far more advanced than others. As technology accelerates, the rate of change in the power of technology accelerates as well. Two hundred years is nothing in evolutionary terms but compare the power and scope of 2014 technology to 1814. Even more dramatic, compare the difference between the military technology of 1935 to that of 1945. Even excluding the Atomic Bomb, the planes, tanks, ships etc of 1945 would simply annihilate their 1935 counter parts. In sum, the total time scales are so vast and the time windows for overlap are so small, that the odds that two roughly equivalent civilizations would evolve at the same time in sync, would be virtually zero. In fact, I rather doubt that any two equivalent civilizations could evolve in the same galaxy. Given the timing issues, I don't think any natural phenomena could reasonably lead to equivalent civilizations. Natural disasters don't have effects lasting longer than a few thousand years which is trivial in evolutionary time scales. You would need some kind of artificial mechanism, something that synchronized evolution and technological development. The obvious solution is to have something communicating between the planets, carrying information of some kind back and forth so that changes in life forms and technology on one planet propagate to the next. Perhaps a stargate could connect the two, or perhaps an elder species leaves AIs to guide younger species and they communicate. I think the likely scenario would be that planet A evolve sentient life first and they go exploring. They find planet B with proto-sentient species and decide to try and uplift. They start the process but some cataclysm overtakes them knocking them back to more primitive level. While they recover, the uplifted sentients of planet B build their civilization, perhaps with some information left behind from planet A's expeditions. By the time each makes it to star travel and they bump into one another, both have forgotten the other's existence. They appear to have found an equivalent civilization despite all the odds. [Answer] I don't believe that human (sentient creatures) progress or its speed is a stable process, so I would find such an occurrence very, very unlikely. Moreover, even by asking your question you assume that their technological level would be comparable. Of course, there are things like [Kardashev scale](http://en.wikipedia.org/wiki/Kardashev_scale), but it doesn't say very much about the civilization itself (and I get the feeling that it's not exactly the kind of "similar technological level" you had in mind). However, the whole idea is not lost at all. Should you synchronize them in any way (e.g. 5 light years away should be close enough to manage some form of communication), then such a thing might be possible, or even certain, unless the civilization would decide on keep the balance off at all costs. To give some examples: * Observe how companies catch up with each other with regard to technology, unless the leader is very secretive about it (and even then the gap is not that big). I hope this helps ;-) Edit: I'll try to find better examples soon. [Answer] The short answer here is sort of a long one. For two separately developed species on different planets to exist either near, or billions of light years away at the same time is highly improbable. So improbable in fact that if it did happen, both civilizations would be too far away to communicate with any known technology. So for them to exist at the same time whilst developing independently and reaching the same technological milestones at the same time is near impossible. There are too many variables even if the planets were identical, the organisms would be unique in how previous generations of organisms developed. They may develop in different climates on the planets and adapt their future generations to fit the environment. 4-billion years of that will not produce the same results, ever. It has been theorized that the time it takes a civilization to develop the technology to create and control radio waves , and the time it takes them to annihilate themselves by nuclear means, is so minute on the galactic time table that millions of advanced civilizations could have come and gone before ours without us ever knowing. Even if by some miracle two civilizations had the same technology at the same time and could communicate through known telecommunication methods, both civilizations would most likely have become extinct before a communication was received due to the extreme time it would take radio waves to get to and back from the other planet. [Answer] The short answer is: no. Even on one small planet such as ours, we can see that some civilizations are thousands of years apart (western civilization vs amazonian tribes for ex.), yet all the "big" events such as dinosaurs' extinction happened on the whole planet and it was only a few millions years ago (65). There was another clash of civilizations when the European invaders met the Central America people. The former had firearms, horses, vehicles, and the later did not yet invent the wheel. The only reason why there is a similar civilization level across most of our planet is the communication level. Until your 2 civilizations can communicate with each other for a long time, there is absolutely no chance they would have any similar (a few hundreds years apart) technological level. On a biological point of view, the whole human history is a 3-4 million years story. Just an instant for the life history on the planet. We don't know what triggered the evolution of a lineage of primates in Africa at that time, but there is absolutely no chance that the same event or events would happen at the same time on a different planet. Actually, it is most probable that the first civilization destroys itself, or is destroyed by some external event BEFORE the second civilization arises. If it arises. More specifically about our neighborhood (< 50 light years away), if any civilization there would exist and would have invented electricity, we would know already... [Answer] While it could happen that a large scale catastrophe influences two nearby solar systems (A [supernova](http://en.wikipedia.org/wiki/Supernova) or [planetary nebula](http://en.wikipedia.org/wiki/Planetary_nebula) are the first things that come to mind), it is unlikely that this would leave anything alive apart from a very advanced space traveling race, or very primitive form of life. The first possibility, obviously doesn't qualify and the second is problematic as well, since there is no telling how long it will take for simple life to develop into complex (and even intelligent) life. One thing I can think of is an asteroid. [It is believed by some](http://www.thekeyboard.org.uk/Earth%20impact.htm) that the sun passes wobbles during its orbit around the center of the galaxy and that this movement periodically makes the sun pass through a dust cloud. This causes periodic meteor strikes. If we assume that these two solar systems move along roughly the same pattern (which doesn't seem like a huge stretch), it's not entirely unlikely that they would experience enormous meteor strikes periodically around the same time. Which would cause an [impact winter](http://en.wikipedia.org/wiki/Impact_winter). If up until that point, both planets had large creatures as the dominant lifeforms (much like our dinosaurs). It is likely that the rule of these creatures were ended with that impact winter. With these huge creatures gone, there would be the possibility for more intelligent, smaller animals to flourish and start their path to eventually become an actually intelligent species. (After a bunch of branches of course.) An additional advantage of this scenario is that the frequent meteor strikes make [panspermia](http://en.wikipedia.org/wiki/Impact_winter) more likely, a good explanation for why life is found in two solar systems so close together. This still leaves a massive gap though. It took us 65 million years to get to the point we are since the dinosaurs died and even the smallest variation there would have one planet able to explore the galaxy (or having destroyed themselves) and the other still swinging from trees. Quite frankly, 300 years is nothing. The only option I see is to have a more advanced race (or a deity, but what's the difference really?) occasionally help both planets out with getting to the next step in their advancement towards space exploration. Here, [directed panspermia](http://en.wikipedia.org/wiki/Directed_panspermia) is worth looking into. The reason why a more advanced being would do this could vary from scientific research to boredom (but what's the different really?). [Answer] There is one scenario that hasn't been considered much. It's the scenario where technology does not continue advancing in a quasi exponential fashion, but rather reaches some sort of stasis, where further advance is no longer assimilated by the society. This seems ridiculous to us, living as we do on the cusp of the end of the industrial age and the beginning of the digital age. But it's an imaginable possibility. Brain Wave, by Poul Anderson, dealt with a slightly different topic. [(See Wikipedia article)](http://en.wikipedia.org/wiki/Brain_Wave). Here, it wasn't technology but intelligence that stopped evolving past a certain point. Except that earth, due to an anomaly, passes from a zone that inhibits the operation of intelligence into a zone that does not. The result is that earth acquires a level of intelligence that can't be reached by normal evolutionary processes. And suddenly. If technological advance does reach some kind of stasis point, then it becomes very likely that two civilizations will be at approximately the same level, even if their ages differ by billions of years. I admit that this is far fetched, but hey. [Answer] I'm happy to say yes! Not only is it possible, but it is certain to happen infinitely many times. While I agree with other answers that the probability of such an aggregate of events is vanishingly small, it is a non-zero probability. There is a compelling argument that says that in an infinite universe subject to ergodicity any configuration with a non-zero probability will not only occur, but will occur infinitely often. Our current science strongly supports an ergodic view of our own universe. It has become mainstream to consider our universe to be infinite, either via eternal inflation or via a multiverse interpretation. Therefore I must conclude that there are infinitely many such neighbouring civilizations. They are probably at each others throats right now! [Answer] I agree with the others that it is highly unlikely (virtually impossible) for two cultures to develop to the same technology over any reasonable period of time, because "the same" is not how technology works. Cultures will find what benefit them the most, and it will be hard to compare a culture that just invented fire against a culture that just invented arithmetic but has no fire. I think the challenge is that your question involved a single event to initiate things, and then both cultures freewheel. If, instead, the event is a long drawn out thing (such as a decrease in radiation levels over hundreds of years), it is more likely that both cultures will run into comparable walls at the same time. As long as the long drawn out thing is WAY more powerful than either culture, it will appear that both are in lockstep with eachother, when the real answer is that both are simply running up against the same wall. [Answer] Given the enormous amount of galaxies with billions of stars and the assumption that life will start on most planets that are neither too hot, cold, heavy or light(1). The unlikely event of two relative neighbouring planets will have nearly the same development stage become not so unlikely due to the huge amount of star systems(2). That Earth is one of these cases is incredible unlikely as the chance that for a given planet instead of any planet will have such a neighbour is extremely unlikely due to the huge lifespan of the planets. > > Could events like that, or something else, synchronize the development > of civilizations at different stars so that they are at a similar > technological level (within about 300 years)? > > > More specifically, could one of those planets be Earth? > > > A super nova in the neighbourhood could reset any advanced technology with a massive EMP. But there is a high risk that it also wipes out all life or all larger lifeforms, in which case the same stage is unlikely again due to the million of years of evolution needed. Another synchroniser is if two systems are hit by a meteor, the sun moves between the 2 spiral arms in approximately 65 million year cycles, and the risk of disturbing the meteors is higher when other stars are near. Again a high risk to wipe out all higher lifeforms or all life. And its unlikely that two neighbour systems are hit in the same time frame setting them back to approximately the same technological level. From the list (1) these are the only synchronizers I can think of. A third possibility of having the same technological level would be if there is a finite maximum level to technology, then a society could develop and hold the same level for a long time while another civilization can arise to the same level much later. That there is some limit to technology is almost certain, that a long lasting civilization doesn't try to destroy itself every 100-1000 year is more of an uncertainty. And the higher level of technology the more likely they succeed in extinguishing themselves. --- 1) The chance that life emerges and develops is more limited than that, for an increased chance to reach a high technological level the following will among others help: * it has to happen at a 3rd generation Sun, to have the right chemical elements. * a relatively stable galactic neighbourhood so that not too many meteors drops nor supernovas explode too often nearby. * it must have an atmosphere and it must not be too dense or thin. * an ample supply of liquid water but not too much. * it must not be too light or heavy * it must not be too hot or cold * a reasonable low amount of radiation, especially outside water to enable higher lifeforms. * an usable form of intelligence must develop * survive themselves, no self extinction * not be neighbours to an advance race who would either colonise the planet or destroy it. See also * [hawking - Life in the Universe](http://www.hawking.org.uk/life-in-the-universe.html) * [Fermi Paradox](http://en.wikipedia.org/wiki/Fermi_paradox) 2) if the chance that life does not develop beyond a certain microscopic level is high, as I believe, then the chance of creating intelligence is increasingly unlikely. [Answer] EDIT -There are three aspects to it Planetary formation For your question Galaxies have a production rate of stars per year (In the Milky Way 3 to 7 per year, but much greater in the past). Two planets can form from the same stelar cloud in two similar mass stars with the metalicity to produce terrestial planets in stable orbits within similar habitable zones, However this stars are likely to remain toguether for at most a few hundred million years. Now to have two solar systems with similar age and conditions unrelated to each other in close proximity is possible but very unprobable. So my guess is that the chances of two planets near each other with similar civilizations is not very likely as per the fact of different starting points or resets to evolution due to extinctions. If the planets would be at a few thousand light years away it maybe more likely as per the stages in evolution of stars (you will find more stars of high metalicity). However this stars and planetary systems will be separated in their creation by tens to a billion years and again if habitability is reset in their evolution this makes predicting it not possible. However if enough space the whole galaxy is taken it is possible to find two planets that were created at the same time with similar conditions. Biological Evolution A-Biology reset by large cataclisms Evolution even if with similar conditions on inception are the same it is 100% sure that both have had different and at different times large catastrophies so creating a difference in the timing and possibly also in the biologica development paths between the two worlds. Therefore biologically distancing them in terms of evolutionary complexity and possibly even afecting the types of biological entities. B-Evolution of Brain size The development of large brains as per number of neurons. (brains developed in three or four different stages and the history of it is burried in the structure of our brain. (A nervous system evolving to a primitive reptilian brain and then evolving into a mamalian brain). This last part happen arround 300million years ago. For this to happen all previous dominant species had to be extinct possibly because in this way large populations could develope and by means of adaptation and intermixing a new genera was created better adapted. Mamals have the longest life spands of animals on earth and also the longest expands in terms of maternity and the long periods of defensiveness of the offspring until maturity is achieved. (It is this long maternity - learning from parents, that created the need for large size brains so their offspring could learn from their parents - This is an smart way nature provided animals means of adaptation to the environement as adaptation possibly is better as it occurs across the life of an individual and is not as determined by the previous genes that were passed to you only although nature prudently keept our ancestral brains also in place so they interis very eact in creating adaptation. Now if evolution has a set of rules (we do not know as we are the only example on earth of a path of evolution) However thre appear to be hints that there are laws to evolution. If this laws are the same every where that of adaptation it is very probable that life evolves in a similar way across the universe. Then if this is the case the containment of brain development is subject to population explossions, extinctions and the development of new species with traces of those prior with the hability to evolve rapidly large brains. In the Genus homo it took 46 million years of monkeys with arms to manipualte things to develop into apes and then 6 millon from this last to the present to grow brains our size. However across time there were 15 maybe more homo genus types with different brain sizes and each specie had a slightly larger brain from the few species only three or four developed suffciently large brains as to evolve into us. They all shared and imnproved certain technology along the way. Humans have 3x to 4x more neurons than the largest brains in the animal kingdom. There is another caveat and is that genuis homo Primitive pre-civilization species tended to be small in numbers even after hundreds of thousands of years Only homo sapiens has multiplied exponentially in the past 50 thousand years and is the only surviving species. So we can see to that to develop a civilization a large population has to exists as to multiply the speed of complexity and thus speed evolution. So as long as there is no explosion in population of any single specie there will be no social development and technology even if large brain exists (case for Neanderthals). Even in the case of neantherthals they had their chance to develop agriculture in the previous interglacial period (130K to 120K years ago) but they did not. There is one issue with this and is social complexity as they were never more than 100,000 individuals at that time while in Homo sapiens there were 4 to 5 million at the time of the neolithic. proximity as a relative term A- Proximity in Space However closeness is relative as per our understanding of the size of the unverse and above all the fastest method of transportation at one time. So 100 years ago we imagined selenites or martians, today habiatable worlds at 50 ly radious and in 10000 years maybe 1/4 of the size of our galaxy. So I would treat proximity with attemtion as it is dependant on our perception of our world. B-Proxmity in Time I think that two similar civilizations could only be able to recognize each other if they both have pursued similar purpose broad goals across their development which are derived from their needs. Could we say that those that were able to make fire a million years ago could recgnize a light bulb (sure) but they will find very difficult to understand how the ligh is generated. So this two civilizations will not be separated by evolution that mach. I think in one million years light may be still in use and possibly in 100 million years. So this is a partial answer as there may be some parts that could be undertood but others not. Could we say that this two civilizations are close in proximity yes because their needs and goals are the same (food, light, heat, raw materials, communication, medicines, etc). However if you expect to find two civilizations developing the plane that will brake the sound barrier at the same time you will not find them. (Space establishes relations between objects in space and time relates them in evolution). However if we would find an extremely advanced civilization it is possible that all his needs will not exist in a more primitive civilization (as would be the case of meeting a computer machine civilization or a non phisical entity) in that case it is very difficult that they understand each other at all. This two civilizations will be separated by billions of years. So as long as there are biological entities they will recognize each other and their goals and needs aklthough it will become wirder and wirder. A ultimate case would be that of an extremely advanced biological civilization that may reach a plateau lasting for millions to hundreds of millions of years where a civilization that dominates and perfects a technology has diminished returns from his development and has evolutionary limits on how it can achive this. Imagine for example a biological civilization that has been able to dominate and manipulate all the existing laws of physics. This civilization may find any further advance is halted by limits by the laws of nature or by the required engineering to an scale which is unachievable or that requires extremely long periods of time or unatainable resources In this case two temporary different advanced civilizations will converge at one point and their differences will became smaller and smaller as the more advanced will find it harder to progress while the younger civilization will get closer to the development point of that more advanced so they become similar. (However for an outside observer there will allways be a difference between the two stages of development but they will resemble more the closest the get). C-Proximity in brain processing capacity What is the procesing capacity of a civilization individuals - The difference of our brain with that of an octopus is 4x more neurons. (And the brain is already prety packed with neurons to the point of saturation). Now if as Paul Davis says biological evolution is only a brief space of time towards any biological entity building machines with incredible intelligence and being surpased by them as per intelligence and capabilities. So far machines have been better than humans in specifc tasks and it is understandable as our brain is the product of an extremely long time spand of well over a hundred billion sucessfull evolutionary steeps and trillions upon trillions of experiments on variable dynamic environements that yields the best possible evolution for survival. So yes intermediate Kardashev\_scale from I to III given the interpretation of similarity in time and that of space provided it will be able to recognize each other although we may find each other culturaly in oposite extremes. Yes possible for the most advanced possible civilizations (hibrid or post biological or non even physical) as they reach a plateau of knowledge where further knowledge and technology progress is limited or capeed. [Answer] Absolutely no chance, whatsoever. Had the ancient greeks figured out electromagnetism, which really isn't that hard (in hindsight), Jesus might just have used the internet. Even on Earth, there are places where travel was possible for millennia, yet technological development was often much more than 300 years apart, e.g. Zulus vs Imperialist Europe. The only way to achieve what you want is extraterrestial or divine intervention, a.k.a. meddling. [Answer] I doubt it would be possible with a civilization composed of people like humans - too often, we advance by leaps and bounds because one random person had a really good idea. And it didn't take all that many really great ideas to get to where we are now, so each one had a huge proportional effect. So let's slow it down. Make both civilizations out of herd animals - slow, incurious, group-thinkers. Give them a slow rate of reproduction and an environment with plenty of resources - necessity is the mother of invention, so let's make invention an orphan. In such a civilization, presumably technological advancement would still happen, because people are still a little curious. But it would happen extremely slowly, and ideas would be generated not by a Swiss patent clerk stuck in an office but by the community as a whole, in a painfully slow fusion-like process. This would make technological advancement slower and more predictable - provided that the two civilizations got started around the same time, there would be a reasonable chance that they'd stay at similar levels for a long while. Now, how do we start them at the same time? Here I'll borrow an idea from Jack McDevitt - omega clouds. In McDevitt's universe, the galaxy is plagued by massive clouds that are attracted to angular structures, and cause destruction when they arrive on a planet. Say we have some sort of similar phenomenon here. Planets A and B start out with civilizations in two wildly different technological positions - but our omega cloud or similar phenomenon comes tearing through and wipes them out roughly simultaneously. Now both worlds are starting from scratch (in terms of civilization, not biology) and we have the synchronization we wanted. ]
[Question] [ Suppose that, after puberty, human beings aged about 15 times more slowly than in our world. Some would still die young (by their standards) due to diseases, wars, accidents, etc., but it would be commonplace to live to be 1000. What kind of effect would a long lifespan (but not immortality) have on humanity? For example, * If women didn't reach menopause until their 500s or 600s, would large families be more commonplace? * How would the institution of monarchy (or other appointed-for-life positions, like US Supreme Court justices) be affected by having the same people in power for centuries? * How would criminal justice be different if it were possible to actually serve a [600+ year prison sentence](http://www.cbsnews.com/news/judge-sentences-ala-man-mark-beecham-to-624-years-in-prison-in-rape-kidnapping-case/)? * How would historiography be different if people who lived through the Crusades, the Renaissance, or the American Revolution were still with us? [Answer] Quick observations: 1. If the people from history were still around, history would move more slowly. The idea that Racism is acceptable in the Western world is decreasing/dead because younger people don't think racism is okay (brought up that way with media and legal influence to ensure it) and the people who thought racism is okay are dying out. The morals/beliefs/stigmas of the past would still be present today even more than they currently are. I don't believe that religion is BS but water nymphs and mermaids are. Likely some people who claimed to have seen them in the 1500's would still be making that claims today. 2. We would have more spread out children. We would still on average have roughly (+50 to 200% likely due to increased unnatural death rates) same number of children to maintain the population. Raising them would however take only 1.8% of our lives compared to 18% now. Our childhood would also be less large the same way. This would mean there would be about 10% the number of children in the world. This by itself is worth of a very long study. Easier to note, however, is that you will have fewer close age siblings. Unless you are twins or your parents are bad with birth control, you will not have siblings within 5 years of your current age. 3. War would be worse. The horrible effects of war including the population decrease would last for 100s of years. Grudges would last longer. America would still hate Japan and everyone would hate Germany. That was less than the equivalent of less than 10 years ago. 4. War would be less. "While I still remember the horrible things you did, I am still wounded from the last war. Our ideologies aren't really that different from the last time we fought." 5. The rate of technological increase would seem larger. This would mean that people who thought the cotton gin was innovative would be trying to learn how to use an Iphone. That would be the norm! Our greatest minds would have 100s of years more to study the universe and (assumed) the memory to support it. If anything the actual rate of technological increase would be faster. Nevertheless, this means that a large portion of the population would be left behind to only do manual labor unless continuing education becomes more significant. Expect to return to school for a decade every 100 years to stay on the cutting edge of whatever exremely nuianced area you are actually an expert in. 6. We would actually make things right! We wouldn't build houses meant to last 100 years... we would construct them of stone. 7. The Rule for Life people would actually be the people who did something. The monarchys of our world have been the children of the children of conquerors. Most monarchs, would be the son of the conqueror who fought by his side. 8. Increase unnatural death rates and death via disease would be observed for several reasons. If every time i go to the store i have some chance of dieing in an car accident, living to 1000 would give me alot more car rides. The same is true for fights with wild animals and older farmer brothers, floods, and extradimensional abductions. If we don't have kids till 200 then more people will die before having kids. More people will die of accidents and disease than old age. This also means more disabled people who survive the accidents living longer. 9. With respect to punishment, if we became able today to live to 1000, I would demand loudly and aggressively for the death sentence for any convicted murderer. Currently a life sentence costs the amount to keep them alive for roughly 60 years. Death sentence costs legal fees plus the amount of time needed for due process (say 20 years). Life sentence is more economical is most cases. If you bump that up to 500 years+ of upkeep... [Answer] Death by old age would be rare. According to the CDC, the [annual rate of accidental death](http://www.cdc.gov/nchs/fastats/accidental-injury.htm) in the presence of modern medical care is around 40 per 100,000, or about a .04% chance of dying from accidental injury in a given year. That means that even with the best medical care available, you have only a 64% chance of living out your potential 1100-year lifespan. Now, project that back into historic times (say, the Roman Republic), with little effective medical care. The concept of a maximum lifespan would be nonexistent: you grow up, and if you avoided dying of childhood disease, you live until something (fall from a horse, disease, infected wound, etc.) "gets you". Almost nobody would die of the diseases of old age (cancer, stroke, heart failure). The impact of this on society is hard to predict. Maybe you get a very risk-averse society where people act to minimize their chance of dying, or maybe you get a fatalistic society on the grounds that "you never know when you'll die, so live for the moment", or maybe something in between. The other major change would be the shape of the demographic curve. In a stable society where the main cause of death is old age, you see roughly equal numbers of people in each age group, until old age kicks in and the numbers drop rapidly. On the other hand, a society where the main cause of death is chance, you get something that looks like an exponential decay curve: many (relatively) young people, and a few very, very old people. [Answer] It would certainly be an interesting place to live! I'll take each of your questions in turn. > > If women didn't reach menopause until their 500s or 600s, would large > families be more commonplace? > > > Yes, the key reason for this is because children continue to mature at the same rate. I believe parents would raise a family for twenty years or so and then settle back to being a couple. After a few decades/centuries they may decide to have another family (one or more children). I suspect it's extremely unlikely that parents would continue to have children every 5/10/20 years, most parents today like to have their children together so they can grow up together. By having age gaps of 20 or 50 years between siblings they would lose this opportunity. > > How would the institution of monarchy (or other appointed-for-life > positions, like US Supreme Court justices) be affected by having the > same people in power for centuries? > > > Appointed-for-life positions would continue to be "for life", however recently the number of for life roles have decreased. After all with people living longer they would expect to be working longer! > > How would criminal justice be different if it were possible to > actually serve a 600+ year prison sentence? > > > This is similar to above, punishments will be given as a proportion of lifespan. After all a 5 year prison term is nothing to someone who will live for a thousand years, it's a minor inconvenience and there's no real fear of the punishments. I expect most punishments will be scaled up as a percentage. For example a 5 year term to us (assuming we live 100 years for the sake of easy maths) would last for 50 years. For more serious crimes you could be imprisoned for 600 years or indeed even longer. Life terms of 500 years would scale too, if someone is too dangerous to be released then they wouldn't be. > > How would historiography be different if people who lived through the > Crusades, the Renaissance, or the American Revolution were still with > us? > > > History would be longer! History is divided into various types * Living memory * Photographed/reliably written history * Ancient history * Pre-history These eras would still apply, they would simply be longer. You would be able to ask your parents about incidents in the 1600s, your grandparents about the 1200s. If you want to go back much further than this you would need to consult written records where they exist. Other Considerations Work and finance would be interesting, people would work for far longer and therefore accumulate more wealth over their lives however everyone would have the same amount of time to do it in. The end result of this would be the rich getting richer and the poor getting poorer (as they're on higher/lower incomes for longer). Expect a more class driven society as people get more embedded in their peer groups. Time would generally slow down, people are raised with a set of views/values in their formative years which are very hard to shake. With longer lifespans these views would last longer. Wars, insults and discrimination would last a lot longer and (as parents have more children) are passed onto more children. Change would come, but it would be slow. Technological advancement would depend on a number of factors. Assuming the human mind didn't slow down or suffer from the effects of old age education would be stretched out and provide far more insight. Students although physically mature would likely study for 200-300 years before starting junior roles. The experts, industry leaders would have had centuries of experience to draw upon. Depending on biology/culture/personality this could hamper advancement (we've done it this way for the last 500 years) or boost it (people know more and have a wider range of knowledge to draw upon). I wouldn't be surprised if there were more career changes throughout people's lives - would you want to work in the same industry for 500 years!? Pets and animals would hold less importance to us, very long lived animals (such as tortoises) would be far more popular. Investment would be made in long term solutions, that line of code you wrote which will only work for the next hundred years? You could still be working there - approaches to quality and resilience to time would be far more robust. TLDR In short not a lot would be different, time would simply scale up. Where things would change would be the family structure. Because people would still mature in the same timeframe I'd expect parents to have several generations of children raised together. As a result it would not be uncommon for parents to have 10-20 children over their livespan split into groups of 2-3 over their 200s-500s. [Answer] Death is the great equalizer. With death so rare, unequality in the world would increase dramatically. People in power would have lot of time to establish legacy for their own children, and they will have very few children. People out of power might have more children - close relatives would be like a tribe, and a tribe with many members would be the only way to oppose people in power. Those in power would feel few restriction to exterminate huge amount of their enemies "working bees", because they know that in few decades they can breed the population back. This new population will be properly scared and obedient. Democracy would be impossible, because it would be against the interest of powerful few, and they will have lots of time to establish caste society. And in democracy, it would be possible for dedicated subgroup to 'outbreed' subgroup with different religious principals, so again it would not work. Google "full quiver", it is happening even now. Technological progress would be much slower, because it requires new generation to accept new ideas - and new generations would be much rarer. And for growing-up person, the indoctrination period (when s/he is expected to listen up and follow orders of elders/authority) would be substantially longer, again slowing progress. Population growth would increase (many women would have different child with different man every few years - they do even now) and so also environmental pressures of the living population on available resources. Possibly most common cause of death would be death as result of war operations. Genocide would be more common, to make sure to get rid of competing population. And likely more acceptable. Is more risk for a woman to have child - so powerful would have polygamy to create tribes of kin. To denying chance to breed a tribe of own kin to other men, castration would be common, especially as punishment to oppose authority. This will lead to very strict caste system and strict paternalistic society. Low worker caste would be bred for low intelligence and obedience. Another caste of warriors would be bred for obedience and bravery. Whole military units would be from close kins, increasing unit cohesion (and potential chance of revolt), so disobedience will be punished in extreme brutal ways (eliminating hundreds of close relatives of any traitor warrior). Arts and crafts would mostly ignored, because most important skill would be plotting your way to the top of the pyramid of power and accounting for centuries old grudges which influence other players (and teaching your own kin about those old grudges, which will reinforce them). [Answer] Assuming that life passes at an experientially similar rate ( so days are perceived much as we experience them ) then these long-lived folk are an interesting proposition. With centuries to live and experience, one might expect that people would have multiple occupations over their lives- if it takes ten thousand hours to gain expertise ( not entirely accurate but a passable guideline ) then the Methuseloids have the opportunity to gain expertise in many activities over their lives- possibly even all the activities. Consequently one might expect them to be generally erudite, having had plenty of time to master many arts, crafts or skills they desired to. A Methuseloid who had dedicated themselves to a single craft over a lifetime could be expected to be one of the greatest practitioners of that craft that had ever lived. In the long range many things that seem important to us are likely to be irrelevant to them- there would be far less need to hurry anywhere ever - but longer term concerns such as environmental change would present a direct problem to individuals rather than a generational concern, so they may be addressed more intensively. Institutions would probably tend towards conservatism as everyone has a clear recollection of the past and experienced a long stretch of it, there would be time to experiment with different forms of government and to choose one that offered comfort and stability. Probably changes would be slower, so leaders might be chosen every twenty or fifty years- in a thousand year life, one would experience 250 american presidential terms. These people can afford to contemplate and think through decisions before they make them. This also gives interesting narrative possibilities in terms of how they might react to rapidly changing events, although they would probably have an equal amount of time to plan for contingencies so they might be notoriously well prepared. I suspect that the idea of a monogamous marriage would be an exception rather than a rule over this type of duration- to us thirty or forty years may be a long time to be with a single partner, to them it is nothing. You might also find this was a fairly sexually liberal society - a "seen it all before" attitude might also mean that they tended to be somewhat jaded about matters of the body and relationships. The dark side of this could be a search for novelty or the risk of a descent into ennui. Looking at human populations, long life expectancies tend to result in lower birth rates and one might expect the same here. In fact with this type of duration it might even be that to enable a shared childhood ( which would perhaps be socially beneficial ) there was some long fertility cycle of - say - fifty years or a century, where the Methuseloids are able to give birth and they are otherwise infertile. In terms of justice, imprisonment seems improbable. Given the long duration of life and the limited population, it is more likely that exclusion or banishment would be a punishment for smaller crimes, perhaps for a few decades or centuries. Execution might also be held in place for more serious transgressions. They may not keep pets unless they could find ones that were very long lived. [Answer] The top-voted answers are great and cover many aspects of what is possible if this is the reality. However, I'm surprised nobody has mentioned population control yet. Assuming that this world is still living in the same Earth we are living in now, it would be a problem if the life expectancy grew by 1000% or so, but the rate at which we are able to produce new offspring would still be the same. # Science and Engineering Since the need for more housing will increase, the rate at which research on other forms of housing (aquatic?) would hasten. We can no longer rely on just land if our population would multiply tenfold (since people die slower). Researches and studies on sustainable living would also be prioritized. # Law I would expect that governments would use their power to control this, and might have a maximum child count per partner. 2 children per 100 years? The law has to take the issue of population control in its own hands if everyone wishes to make the Earth a livable place. According to [this link](http://www.worldpopulationbalance.org/3_times_sustainable) : > > Earth’s 29.6 billion acres of biologically productive land and water > could sustainably support only about 1.5 billion people at an > 'American standard of living and consumption.' > > > [Answer] I go back and forth, I think having long life expectancy would make people more like Tolkien elves, then I think about if everyone was rich, no one would be rich. Meaning if everyone could expect to live on average 700 years, it might not be terribly different than now. Things that would make a difference, having a 5-600 year fertility period for women would likely mean no reason to have more than one at a time at home, maybe have one every 50 years or so, make sure each one has a good strong start in life. Homes would likely to be very different, the average home in the US I think is expected to last about 100 years. So having to rebuild your home 5-8 times over your life could be problematic. Likely stone, brick, and steel will be much more common for structures. That is also a very long time to 'collect' junk. Having a life expectancy that much longer would also slow down changes by evolution, likely having about 1/5 - 1/10 the number of generations over the same time period. That is also a very long time to remember things, so either larger brains would need to be grown, or very large parts of ones life would just be forgotten. [Answer] Birth control is going to be a major event in the history of this world. I don't have any hard numbers on the mortality rate of pregnancy in pre-modern times, or how different that rate might be between, let's say medieval europe and china, but I suspect it's not good. Now multiply that over a lifetime with 50 pregnancies, or a 100 pregnancies, or maybe even 200 -- a woman is overwhelmingly likely to die from pregnancy complications or childbirth at some point. Now maybe social norms and behavior would change in accomodation for this -- maybe less frequent intercourse or something like that. But that didn't happen in our actual world and pregnancy was pretty risky even for us. Another point to consider is what else about our physiology would have to be different in order for long life spans to evolve. In the real world, there's no selection pressure for longer life once you've lived long enough to push out a few offspring. So maybe people are much less fertile in this world? You've ruled out a longer development time for juveniles. [Answer] This went way long but I have some apparently counter intuitive conclusions so I fleshed them out. At the top is the summery and and answers to specific question of the OP. Below are detailed arguments if you wish to read them. (Anyone who does so gets a cookie.) My core conclusions are: * Methuselah's would have a society based on flexibility, adaptability and change. * Methuselahs would develop technology more quickly. * Methuselahs would have a less hierarchal more egalitarian and merit driven society. * The idea that youth promotes change and adoption of good new ideas is not historically supported. A society of Methuselahs would be not be inherently more static. * Societies don't change because old people die, they change to adapt. * Elites cannot control society to prevent change. Specific answers: > > If women didn't reach menopause until their 500s or 600s, would large > families be more commonplace? > > > Simply having one woman fertile over a few centuries instead of a series of women over the same span, would not change the overall birthrate. Humans have regulated birth rates since hunter-gatherer times. People have the children they can support in a given environment with the already extant population. That would be true regardless of how long we lived. A long lived species of humans would not have much turn over so they would have to limit replacement births. Their populations growth in absolute size would mirror our own, expanding gradually up during the agricultural era when children are important for labor, then a slight uptick at the beginning of industrialization, then a sharp drop off as children began to absorb more resources. > > How would the institution of monarchy (or other appointed-for-life > positions, like US Supreme Court justices) be affected by having the > same people in power for centuries? > > > Not much. The practice is largely followed in countries that still have substantial adherence to common law i.e. historical defined law. Judge's power was checked by the precedents set by previous generations so no other mechanism was needed. The major function of life time appointments was to limit the power of outside actors to influence judges, by influencing their reappointment. That dynamic would not disappear. If people pursued multiple careers in their lives, they would likely switch to a system we use with US Presidents, a fixed term coupled with an ban against serving again. So, you could be a judge for 50-100 years but then you'd be out of judiciary forever. Judges would be independent while sitting and then have to switch careers. > > How would criminal justice be different if it were possible to > actually serve a 600+ year prison sentence? > > > Bizarrely long but fixed prison sentences are the result of the very strange accounting system used in the criminal justice system. It got really baroque in the 1960s. They are intended to serve as life sentences for accumulations of crimes that individually, for whatever reason, cannot individually warrant a life sentence. Not all societies use them and they used to be rare in American. The prison is only partially deterrence from loss of freedom. The experience of the last 40 years has shown that the primary good performed by prison lays in simply isolating transgressive individuals from the general populations. That need wouldn't go away in a society of Methuselahs. If I had to guess, I would say that the Methuselah's awareness of change (see below) would likely lead them to promote capital punishment as a means of avoiding shifting conditions or chance from freeing a dangerous individual centuries down the road. That happened for real in the 1960s when radical and unanticipated shifts in culture, law and criminal justice theories released large numbers of people who had years or decades before been sentenced life or even death. In some case, individuals sentenced originally to death either killed again in prison or were freed by corruption or accident e.g. Kenneth McDuff, and went on to kill again. After a few centuries of experience, such an outcome would likely seem more likely than not so executions would seem a more certain form of both justice and prevention. > > How would historiography be different if people who lived through the > Crusades, the Renaissance, or the American Revolution were still with > us? > > > I think the biggest change would be the ability to think of or ask question not on anyone's radar at the time. For example, prior to the 1600s, technology was almost entirely undocumented because no one of the age thought it particularly important. Most of what was documented concerned weapons. We detailed plans and models of on warships from the 1600s but rely on archeology to tell us about merchant ship construction as late as late 1700s. While providing insight, long lives could also make historical studies more difficult. Firstly, we have trouble discussing "living history". If the actors of events are still around, especially, if they are still prominent, things get hairy. I spent a big chunk of my life watchings Baby Boomers bob and weave around the Vietnam war even after the end of the Cold War. Secondly, lot of recollection would be fouled by hindsight bias. Nobody is right all the time or even most of the time. When you read great works of philosophy and science from the past, what you see is 90% flat wrong with a few perils of pretty-close. On social and political matters, everybody would be seriously wrong to point of disgust about something e.g.Lincoln would be considered a hard core racist by contemporary standards. People writing about their conduct in the distant past would constantly try to reinterpret their actions in modern terms e.g. I'm old enough to remember when leftist declared the idea that being gay was somehow physiological intrinsic was impossible and fascistic and who mocked the the idea that gay people would ever get to marry as right wing hysterical fear mongering. You won't find any advocates for gay rights from the 60s-late 80s, owning up to those then universal stances anywhere today. Thirdly, people write contemporary they expect to be read in their lives differently than they write accounts they expect to surface only after they are gone. Diaries are different than newspaper editorials. People who lived centuries would likely write with biases assuming that they would be around when all their writing became public. --- ## Details Methuselah's would have a society based on flexibility, adaptability and change. Each individual would experience and remember more change and thus be more aware of the need for individuals and societies to be willing to change and adapt. If nothing else, their view of the natural world would be one of extremely fast and constant change. River courses would whip about like snakes. The sea would visibly eat into the land. Mighty oaks would grow and die like shrubs. They could breed plants and animals over centuries or even millennia which would make life itself seem plastic and shifting. (Someone 500 years old today would remember when most fruits, vegetables, strains of grains breeds of dogs, cattle, sheep and horses etc did not exist.)Every middle-age adult would remember large numbers of superstorms, earthquakes, volcanos, plagues etc. The cyclic motions of astronomical objects would be readily apparent, as would the cyclic decadal shifts in climate that occur in every region of the earth. Natural resource bases like game lands, potable water,arable lands, navigable water ways or veins of ore would seem constantly shifting and ephemeral. Likely, they would never develop the concept of a "natural" resource at all since every individual would see many changes in how resources came into being from human effort and how resource use shifted and changed constantly. In human interaction, they would see more examples of fluke and chance, more lost horseshoe nails loosing battles for example, and would be less likely to see current social structure as something fixed and eternal. Certainly, the rise of literacy and historical research of all kinds has given us today long artificial memories and made us more aware of the constancy of change and our need to always adapt. Imagine how much more we'd believe this if we personally remembered those changes. Methuselahs would develop technology more quickly. Longer memories of individuals would mean greater and faster accumulation of knowledge in pre-literacy times. Until well after the 1600s most technological knowledge was passed directly person to person. A break in the chain caused the loss of the knowledge. People with 1,000 year old memories would not have that loss. Long life means lots of time to learn new skills explore many avenues of thought. Each individual would have a wide range of skills of all kinds which they could bring to bear on science and invention. There awareness of the need to change and adapt would create a powerful incentive to look for more new technologies and adapt them. Methuselahs would have a less hierarchal more egalitarian and merit driven society. Thinking long term, and much aware of change and chance, when on top, they would value the potential for long term cooperation centuries hence from those currently on bottom when the shoe might well be on the other foot. Just like the rise of long distance sea trade cause people to worry more about a captain's seamanship than who his daddy was, long term planning for inevtiable change would make them value skill and merit more than the alliance du jure. More time to learn skills would mean more time to acquire military skills which would make it more difficult for a minority warrior elite, trained since birth, to dominate a large population of craftsmen and farmers. In all known human societies, greater equality of military skill and service has lead to greater social equality while greater inequality leads to the opposite. The inability to block individuals from rising on merit by force would also contribute positively. With each individual having the time to learn many skills, society would be less interdependent and more robust against of disorder and disruption. In a pinch, you do without a blacksmith because everyone would know a little blacksmithing. As such, political changes and fragmentations would not present as much as problem as in societies with a high degree of specialization of labor, and a high degree of interdependence. The idea that youth promotes change and adoption of good new ideas is not historically supported. So, a society of Methuselahs would be not be inherently more static. Kinda of a modern idea, probably linked to flattery in advertisement and advertisement supported media which is overwhelmingly aimed at the young, because the young respond most strongly to advertising. Historically, it has no basis. Most science and technology development is done by people 25-35. Most business innovation by people 30-50, and most political innovation by people 45-60. E.g. the Civil Rights movement was carried out by the Greatest Generation and the Great Depression generation who where in their late 40s to early 60s in the 1960s, not the then snot nosed Baby boomers. Basically, all the heavy lifting or organizing and getting things don is done by people around 50. People who are older wear out and can't keep up more than growing mentally inflexible. Societies change when their internal or external environments change and they must adapt. When that happens, those with the most existing power and skill implement most of the changes. Young people play the same role in significant and enduring political and social change as they do in wars i.e. foot soldiers. To the extent that youth does promote change, its often random as to whether it turns out good or bad. Fascism and Communism were considered youth movements in their heyday of the 20s and 30s. Older people are much better at filtering bad ideas, the majority, and focusing on those that will produce lasting improvements. The effect is even more profound because important changes tend to be rather boring at the time and only people with discipline, experience and an eye for detail can carry them out. Having longer lifespans would improve this skill as well as reinforcing the need to change and adapt, a relativel lack of young people would have little effect. \\ Societies don't change because old people die, they change to adapt.\\ By our standards, most historical societies had a higher ratio of young to old yet they remained static for far longer. If young people drove change and old ideas died because the people who held them die off, societies with higher death rates at younger ages should change faster. They didn't and don't. Every core change in every society occurred because older, wealthier and more powerful changed their behaviors even if they didn't change their stated ideals. From religious reformation to political "revolutions" (really lateral shifts) to Civil Rights, the people that had to change to make the change stick were older, more experience, skilled, and overall effective people i.e. the people who get most of everything important either done or coordinate getting it done. Methuselahs would be no different. Their long lives would see many changes in nature, technology and society. If they keep trying to act like it was 1300 in Germany the medieval warming period 1777 Massachusetts during the little ice age, they wouldn't last long. \\ Elites cannot control society to prevent change.\\ Another myth, largely perpetuated by those trying to explain why their particular really, really great and obviously true and perfect idea didn't succeed in radically restructuring society in a weekend. Far from being inerrant puppet masters or engineers arbitrarily structuring society to their own benefit or whim, elites are historically dullards constantly blindsided by change. This happens because changes usually start small and by the time they appear to be of consequence, it's to late. Social and political change usually occurring owing to changes in the environment or in technology, neither of which elites control. This is particularly true in the case of technology. New technologies start out about as distinctive as individual tadpoles. Only in hindsight is their rise obvious. Nobody has ever succeeded in suppressing a useful technology despite the fact that every single new technology ever, has threatened some established interest. So, not only would Methuselahs be more positive towards change, have an less elitist dominated society, they wouldn't be able to stop change even if they wanted to. --- Methuselahs probably would have hit the industrial age within a few thousands of years after the end of the last ice age, say around BCE 5000. At our stage of development, they'd probably be planning on nipping on sublight starships. What's a five hundred year stellar voyage to someone who will live to be 1,000? [Answer] The main cause by which History advances is that people keeping old ideas alive die. If the tribe has a hunter that keeps hunting mammoths (or elephants) for 1000 years, you can not expect that very person to lead the tribe to technological progress. We will simply still be at stone age. New inventions would have been forbidden, since them make the bosses unease. [Answer] * People would go through something like a midlife crisis every couple of decades. The process would be similar to what a young adult does when they leave their parents' house, except that you would leave your old existence (family, job, most material objects) behind. The process is called molting, a personal reinvention that is fueled by the feeling of being stuck. It often involves another round of education. * While molting allows people to pursue new endeavors there is no replacement for the curiosity and open-mindedness of youth. The society will be terribly gridlocked in its ways. Science and technology will progress very slowly. * The old ones will not accept the very few young ones because obviously, they have no clue. The young ones, in turn, will feel excluded from participation and despise the old ones for their mental immobility. They will seek to distinguish themselves through language, music and fashion. The society will be sharply stratified by age: You will immediately be able to recognize members of your age group. You'll share in-jokes that no other group can understand. You'll despise both younger and older groups, which resembles the mutual boomer/millenial contempt, just harsher and more varied. Residential areas will be zoned, officially or unofficially, by age group because they cannot stand each other. * Life as an individual will be a constant reminder of old memories. Population turnover will be very slow, and you'll have met many people in your field of profession or hobby (that is one reason for molting). Whenever you change jobs you'll recognize people you know from earlier jobs, and vice versa. That is, of course, a mixed bag. You could sum that up as "there is less anonymity". The same is true for social circles. When you meet a new group of people, say, in a sports club of which you have become a member, there is likely somebody who witnessed the divorce from one of your 23 past wives (none of the break-ups was pretty). Or if you were never married, you can see the place of at least one of your 300 exes from any point in the city you have lived in for 600 years. * One of Djokovic, Federer or Nadal has won 987 of the past 1200 Grand Slam tournaments. Of the past 300 Ballons d'Or, 197 were won by Messi and 86 by Ronaldo. The 17 remaining ones were given to lesser players in seasons when both Messi and Ronaldo were injured. Messi has played in 37 clubs in the past 300 years and won the Champions League at least once with each of them. ]
[Question] [ Airships are a hallmark of countless steampunk and dieselpunk constructed universes. Of course, in our world, they were around for a short while. I want to know what effects geographical circumstances had on this. I feel like one thing that lead to the death of airships as a viable form of passenger transportation in real life was that it took days to travel from New York to London, especially with the advent of jet airlines. If that's true, what type of proposed global geography would be most beneficial to a strong airship industry? I'd imagine either a world full with archipelagos with numerous small islands, with many medium islands and a few large ones as well (the largest having an area approximately similar to Honshu or Great Britain;) or a world with slightly more land density, with no more than two the size of Australia. I see that an island-based world would grant short travel distances between major regional population centers, many islands would mean that railways would be only of regional importance, and airships would have the advantage of transporting people on a regional basis at a speed faster than an ocean liner. I also am aware that the Hindenburg disaster helped kill airships; which was influenced by the USA's ban of helium sales to Nazi Germany. As helium is extracted from natural gas fields, I would also presume that, at this point in tech level, more geopolitically balanced natural gas deposits would benefit as well. What other geographic affects would there be on airships? Do these ones here make sense? [Answer] The main reason airships stopped being used (apart from the hydrogen safety issue) is speed. Airplanes just get you there faster, a lot faster. In a hypothetical world where wings were never invented (or just don't work), or where high density power sources such as aviation fuel are not available, then airplanes would not take over and development on airships would continue. For example one big factor that if changed might help airships remain dominant is gravity. Increased gravity would make it much harder for wings to function, but would not affect airships anything like as badly. The presence of strong and reliable trade winds at certain altitudes or locations would also help with this, get the airship to the correct position to ride the trade winds and it will then take you where you want to go. It may interest you to know that airships are still not completely out of the running in the real world. There is a lot of interest in using them as heavy lifters since they can carry massive loads much more cheaply and easily than other air transportation and several military and civilian outfits are looking into them. ![A next-generation airship](https://i.stack.imgur.com/D5r88.jpg) <http://aeroscraft.com/aeroscraft/4575666071> [Answer] Easy access to a gas with a lower density than the rest of the atmosphere would help. In our world the available alternatives for this are: * Hydrogen which is easy to manufacture in large quantities but [has proven to be too unsafe for use in airships](https://en.wikipedia.org/wiki/Hindenburg_disaster). * Hot air which is free and has the great advantage that its density can be adjusted by adjusting its temperature which allows to regulate the height, but requires a constant heat source which makes it resource-intense. * Helium which is both safe (like air) and has a density which is almost (but not quite) as low as hydrogen. The main downside with it is that it is very expensive to manufacture. For further reading, I recommend [the Wikipedia article on lifting gas](https://en.wikipedia.org/wiki/Lifting_gas). A society which has easy access to a gas which is lighter than air and safe to handle would likely develop balloon/blimp based transportation much earlier than aerodynamic flight. A possible world could be one with a layered atmosphere where the lower layers are breathable air and the upper layers are pure helium. When the world has mountains which are so high that they reach into the helium layer, those could be used to harvest the helium and use it for airship construction. When there aren't many of such mountains, they would be of huge economical value. To make air travel even more important in this world, it could have obstacles which can not be crossed by other means than by air. As we already established a layered atmosphere, why not make the lowest layers of the atmosphere consist of a heavy gas which is toxic and/or corrosive (the guys at [chemistry stackexchange](https://chemistry.stackexchange.com/) might have some nasty suggestions), so that life is only possible on isolated islands which are on a height between the toxic layer and the helium layer. Travel by aircraft would then be the only feasible method to travel over the toxic chasms between these islands. [Answer] Perhaps an extremely mountainous landscape, with cities separated by mountain ranges higher than Everest? Airships can manage very high altitudes and don't require long runways for landing. Moving bulk cargo through such extreme mountains would be difficult. With plentiful helium as suggested by Philipp, airships would have a natural advantage over trucks, trains and ships. There are of course heavier than air planes that can operate in these ranges too but they have limited capacity and need long runways. Passenger airliners, cargo planes and helicopters wouldn't be able to reach the required altitude to cross the mountains. Higher altitude aircraft might still be used for military uses, airmail and (costly) passenger transport. [Answer] How about a world where I don't think any other form of long distance transport would be used: 1) The atmosphere is extremely thick but contains a very low percentage of oxygen. A look at how scuba divers fare shows that our lungs care only about the partial pressure of oxygen, not what percent of the atmosphere is oxygen. Thus it is reasonable to assume ETs with the same pattern. Combustion, however, depends on the ratio. An atmosphere with a sufficiently low oxygen pressure won't support combustion. Again, we can see this in the really deep dives--you can have a mix of hydrogen and oxygen that will not burn but is breatheable at depth. 2) The world is part of a close binary which itself orbits a bigger planet. (Robert L. Forward, Rocheworld, although with less water) The result is extreme tides, no large land mass is possible because the water has to flow somewhere. It also means a lot of vulcanism. Thus you have a world of islands in a sea that will smash your ship against the rocks if you don't time things perfectly. Such a world means no fire-based propulsion other than rockets--and with an atmosphere like that no chemical rocket is going to make it to space. Even the military uses of rockets will be limited because they simply won't go very fast given the density. Sputnik will ride an Orion. The tides mean no meaningful shipborne transport, it's too dangerous to be on the ocean anywhere remotely near land. You might see some hydrofoils that can make a short crossing timed with the tides but that's about it. The islands mean no long distance roads or trains. Note, also, that the dense atmosphere increases the lifting power of a hydrogen or helium based airship. (Given the atmosphere a hydrogen based airship is safe enough.) This means they can be much smaller than terrestrial airships. [Answer] One disadvantage of airplanes is that they need a runway to start/land. So one thing that would discourage airplanes is a geography where you simply have no space for runways (hills/mountains everywhere). Also, airplanes depend on the availability of cheap fuel, so if you don't have that, they cannot compete against airships. So you'd need a geography with no fossil fuel deposits (or at least none which are economically viable to exploit). Another possibility would be the lack of hard but light substances to build airplanes from. Another thing that could discourage airplanes is if there are many birds that could interfere with the airplanes (get into the propeller/jet engine and kill the aircraft). Airships are immune to them as long as they are not directly attacked. To have many birds, you'd of course need a bird-friendly geography. A bird-friendly geography would mean: * many food sources — for birds that eat insects, that may mean many lakes, and an insect-friendly climate (no cold winters, much humidity, but little direct rain), for birds eating seed it would mean many plants with those seeds. * many places where they can build their nests — which depending on the type of bird may mean many rocks, or many trees, or simply many open areas if the birds build their nests on the ground. * maybe also a relative lack of land animals that could compete on the food, or eat the eggs of the birds; that could be caused e.g. by there being little continental land, but only many small islands which are too small to support animals that can neither swim nor fly. As a side effect, those would also be detrimental to building long runways. [Answer] One of the things that recently reduced the amount of air travel here in Europe was the volcanic eruption of Eyjafjallajokull which placed a lot of ash into the atmosphere, presenting a risk to planes. Volcanic ash is highly abrasive and quickly causes harm to propellers and jet turbines. If we were to imagine a world where something like the [Deccan Traps](http://en.wikipedia.org/wiki/Deccan_Traps) was still in operation, or there is very frequent and intense volcanic activity, it is possible that there would be sufficient ash in the atmosphere to make early aeroplane engines or propellers non-viable so that technological avenue may not be significantly explored. Dirigibles would be able to operate with fewer moving parts, effectively sailing for the majority of their journeys, and consequently stay viable in this type of scenario. [Answer] There is one kind of planet on which airships remain feasible and heavier-than-air craft are not: one with an extremely thin atmosphere. This is, at first, counterintuitive: airships rely on buoyancy, so they perform best in very thick atmosphere. However, "best" is relative. Heavier-than-air craft are even more limited by thin air. Consider the [Wikipedia article on Flight altitude records](http://en.wikipedia.org/wiki/Flight_altitude_record): the balloons beat the heavier-than-air craft every time (not counting rocket planes, thanks). It's easy enough to explain that. Consider what happens to a heavier-than-air craft as it goes as high as possible. It starts to mush along, unable to ascend anymore, because its engines simply can't provide the necessary thrust to generate increased aerodynamic lift in the thinner air. By contrast, a lighter-than-air craft that flies too high experiences uncontrolled ascent, because the gas bags expand. If it doesn't have emergency venting capability (which they all do, realistically) it's doomed. The gas envelope, expanding with diminished pressure, will split open - if it's a dirigible, it may damage the airframe first - and the ship's gonna fall out of the sky. I don't know how much better illustration there could be of the superior flight characteristics of lighter-than-air craft on a planet with thin atmosphere. It's a fairly sound assumption that, the thinner the atmosphere, the less likely that a technologically advancing culture would develop heavier-than-air flight in the first place. And that if your premise is that an already technologically knowledgeable group of people had entered the world from elsewhere, they would make the same kind of engineering choices. Now... IF you would accept this as a worldbuilding premise, there'd be a lot of work to do, a lot of questions to answer: * How much lower ambient air pressure would the world need to have, in order to establish the primacy of lighter-than-air flight? * What does the answer to the previous question say about the habitability of this world? Are the inhabitants human? If human, what measures do they need to take in order to live there? Loren Pechtel, above, is entirely correct about partial pressure of oxygen; that would be your first line of inquiry. * If the world has very low atmospheric pressure, does that preclude flying animals? What about flying insects? Any likelihood of lighter-than-air animal forms? What about windborne seed and pollen distribution? The ecological implications could be interesting. One more thing: it may not be necessary to postulate an entire world with a scant atmosphere. It might be reasonable to topographically separate the habitable zones with intervening areas of extremely high altitude. A flat land at very high altitude, perhaps, cut with miles-deep canyons, with people living along the bottoms? No feasible way of traversing the high areas except by airship? If you do that, though, you will have to be very careful about wind. Turbulence and wind shear are, in our atmosphere, exceptionally dangerous for airships. How that would play out in a much thinner atmosphere is hard to say, but it's probably something you'd need to work though. [Answer] In order to construct a scenario where airships are the preferred form of transport, one needs to assess the relative merits of different forms of transportation. If you have lots of islands, ships would almost certainly be preferred. They can have considerably higher cargo capacity, be faster, easier to construct/maintain, operate in more extreme weather, etc. Large watercraft will need to be unavailable. Land transport is far superior over flat stable ground (or ground which can be made so), so essentially you want ground over which heavy duty roads are not plausible (maybe too unstable, needing constant maintenance and still prone to washout/blockage, or too environmentally damaging, etc). Broken hilly terrain (mountainous in the sense of Appalachians not Rockies else weather will be too deleterious to aircraft) prone to mudslides/avalanches, or possibly heavily forested wet areas like the Amazon rainforest, or sparsely populated Siberian tundra would favor air transport. Dirigibles and blimps can be highly efficient for large cargoes. Despite their slow speed, their considerable weight capacity (compared to heavier than air vehicles and even trucks if large enough) can easily offset that by reducing the number of trips needed (and allowing for the transport of larger items). Instead of needing to ship components one at a time on the back of a truck and constructing a facility onsite, considerably larger units can be put together and lifted over mountains to the final destination, without the need to construct roads capable of supporting a parade of heavy trucks (leave any roads for small lightweight cars rather than cargo). Environmental concerns favor airships - low impact to the environment as they can travel point to point without destroying a swath between locations for roads (especially if windy switchbacks need to be cut in hillsides), only need a cleared area to get close to the ground or even just a nice aeroport tower to dock to for loading/unloading, and comparatively low fuel usage (if going for modern tech rather than your mentioned steampunk - solar powered engines). It may be too slow if primarily carrying people rather than cargo - heavier than air craft may still dominate for passenger service (at least for most cases - dirigibles will still be cruise ships), or for fast postal service. In short, wherever you do not have access to ocean or readily navigable rivers for shipping, and it is impractical to build or effectively maintain roads/rails between destinations, airships are plausible as the dominant form of transport. [Answer] ![From the Scott Westerfield Book: Leviathan](https://i.stack.imgur.com/VHL1W.jpg) Your world could grow airships, all you need is: AIR PLANKTON! But in all seriousness, all your world would need is a whale species that inflates itself with helium or hydrogen when it reaches adulthood to reach a creature that could feed its massive self. If you have a whale big enough, it could even have other air creatures that live on/in it and help feed it. Then, get some really clever maniac who captures and domesticates a few and you have "instant" airships, just add harnesses! [Answer] One way to have an easy source of light gas without the earthly dangers of hydrogen is to have a reducing atmosphere-hydrogen, methane, ammonia. Water is allowed as well. The chemistry of the living things needs to be adjusted. The fuel manufactured by photosynthesis has to be an oxidizer instead of a fuel, which would be "burned" with the reducing chemicals in the atmosphere. Plants would keep the oxygen from splitting water and exhaust the hydrogen to the atmosphere. There is a lot of work to flesh this out. As far as geography, not having oceans that are useful for moving cargo might help. The slow speed of airships is not so bad for moving non-perishable commodities, like things that move by ship on earth. You care more about the total flow rate than how long a particular item takes to be shipped. [Answer] Maybe the answer is more psychological: imagine a culture in which people value comfort & sightseeing opportunities over simply getting there quickly. The people might be wealthy, long-lived, have advanced internet telepresence for business purposes, so travel is only for pleasure. Or perhaps the potential of large, high-speed aircraft as weapons is seen as even more of a threat than it is in this world. [Answer] You could have an alternate history about Earth where certain major events did not happen such as the Wright Brother's successful flight at Kitty Hawk, and the Hindenberg disaster. Perhaps Orville and Wilbur Wright gave up before they figured out how to design a working aircraft. Maybe Adolph Hitler died of syphilis before he could get into power, and Germany never entered WWII. In a world such as that, it would be logical that the airship would still be widely used today. As far as geography goes, a world without many navigable waterways would make it impractical for ships to transport cargo and people. A lack of solid, flat ground would be a big problem. Airplanes are heavy, and require very solid ground to land on. If most of the land was swampy/marshy then there wouldn't be a good place to build runways. Large mountains would also pose issues. Travel by train would also be impractical in those situations. [Answer] Other answers pointed different advantages of airships and the geography that would make them useful, but I think one advantage is missing: autonomy. Airships could fly without resupplying for much longer than contemporary aeroplanes and it took decades for airliners to reach the same range. Therefore, in a world with larger islandless oceans, airships could be common for a long time. For example, if our world had just two continents (Europe and Australia) with no islands at midway between them and we assumed the actual technological progress timeline we have had in real world, airships would have been the only alternative to ships for more than half of a century. [Answer] Tom Kratman's [Terra Nova](https://www.baen.com/a-desert-called-peace.html) has four significant differences in geography from Earth: * The sun rises in the west. * The Mediterranean is broken up into large lakes. * There is a large island somewhere between New Zealand and Chile. * The planet is less tilted than the Earth. This reduces the risk from windshear and other severe weather. On Terra Nova, large lighter-than-air vessels that are shaped to achieve dynamic lift are the preferred vessels for reasonably quick freight transport. Such vessels do not go into active warzones. They also compete with heavier-than-air vessels and cruise ships for passenger travel. [Answer] Many good valid points on airships. On geography, high mountains, deep valleys, extreme open spaces with low populations/commerce. Airship viability depends on human a/o economic needs. Airship: cruise vacations, high altitude (over 16Km) telecommunications platforms (satellite substitute), heavy lift logistics point2point for storm/catastrophe relief or science or military ops, regional hospital coverage.... Airship: Skin/shell provides solar power for internal functions, propellers... and medical, public education/schools, telecommunications... functionality. UAV, geostationary for extremely long periods (maybe three years) only lands for maintenance and upgrades on ground.... Extreme/remote mountains/terrain would justify airships for modern conveniences and services. <https://www.google.com/search?q=high+speed+airship+2018+telecommunications+platform&prmd=nisv&source=lnms&tbm=isch&sa=X> ]
[Question] [ I'm trying to design a food chain. For the sake of argument lets say it's based on flying creatures over a particular mountain range. ``` Sun Plants/Fungus etc Tiny Insects Small Birds Hawks Large Apex Predator ``` However I'm struggling with getting the balance right. Obviously the big predators are the more interesting animals and the ones which drive the story but I want to ensure there are enough small birds and animals for them to eat. If I want three large apex predators (each weighing 100KG) how many KGs of hawks would I need to sustain this population? How many KGs of small birds? [Answer] The 10% conversion efficiency mentioned in other answers is a decent rule of thumb — there's a lot of variation in the real world, but if you assume that the total prey biomass equals somewhere around 10 times the total predator biomass, you'll get a fairly plausible-looking food chain. Tim B makes an excellent point in the comments, though: generally, even apex predators mostly hunt herbivores, simply because they're usually the easiest and most abundant food source around. So a 100 kg apex predator does not need 1,000 kg of lower predators to support it — it just needs 1,000 kg of some kind of prey, which may include both herbivores and other carnivores. In fact, in real life, many apex predators (such as bears and, indeed, humans) are even omnivorous to some extent, consuming some plants (usually parts with high nutritive value, like fruits, nuts and berries) to supplement their hunting. Indeed, one major advantage of a flexible omnivorous diet, for species high up in the food chain, is that it helps guarantee a steady food supply, minimizing the risk of mass starvation (from which apex predators, with their small population sizes and long generation times, have a hard time recovering from) due to fluctuations lower down in the food chain. Conversely, since apex predators, by definition, have relatively little competition, they don't suffer such a strong pressure to specialize as species lower in the food chain, and can thus afford to maintain a generalist diet. Actually, the only reason everything in nature isn't omnivorous is that different nutrition sources sometimes require incompatible adaptations. For example, the reason why autotrophs (plants) and heterotrophs (animals) are mostly distinct is because efficient autotrophy requires some adaptations (like a low-energy sessile lifestyle) that are incompatible with those needed for efficient heterotrophy (in particular, mobility for grazing/hunting). Similarly, the distinction between primary consumers (herbivores) and secondary consumers (carnivores / omnivores) is a follow-on effect to this: efficient grazing on such a low-density nutrition source as most plant tissue requires behavioral traits and digestive adaptations that are not well suited for hunting, and vice versa, so while a predator may occasionally eat plants, it is unlikely to be able to survive well on plants alone. However, on higher levels of the food chain, this specialization starts to break down: the adaptations needed to hunt songbirds are not that different from those needed to hunt falcons, so an apex predator that can do one will most likely be capable of both. They're still most likely to hunt mostly songbirds, though, simply because there will be a lot more songbirds around than falcons (and also because songbirds will likely be easier to catch, and less likely to fight back, than falcons). (In fact, IRL, falcons would generally be considered apex predators themselves. While there are species that may, occasionally, kill and eat falcons, none of them really do so routinely or to such an extent as to put any significant predation pressure on the falcons. To a first approximation, nothing eats falcons.) --- So, with that out of the way, how should you figure out the biomass of different species in your ecosystem? Well, the first step would be to roughly sketch out the [food web](//en.wikipedia.org/wiki/Food_web) for the ecosystem. For example, a quick sketch might look something like this: * Large apex predator (100 kg), large carnivore: + Mainly eats mountain goats (80%), supplemented by some lemmings (15%) and songbirds (5%). + May opportunistically eat falcons, but not very often (< 1%). + Does not usually eat insects (too small to hunt efficiently) or plants (not easily digestible). * Mountain goat (50 kg), large herbivore: + Mainly eats plants (> 99%); can eat almost any plant, even those inedible to most other herbivores. * Falcon (0.2 kg), small carnivore: + Mainly eats songbirds (25%) and lemmings (75%). + May opportunistically scavenge mountain goat remains left by apex predators (< 5%). * Lemming (0.1 kg), small herbivore / omnivore: + Mainly eats plants (90%; shoots, leaves, roots and seeds / berries) and some insects (10%). + May occasionally eat eggs (< 5%) when available. * Songbird (0.02 kg), small herbivore / insectivore: + Diet consists mainly of insects (50%) and seeds (50%); proportion varies by season (mostly insects in spring / summer, seeds in autumn / winter). * Insects and arachnids: + Broad group subsuming a complex sub-ecosystem of herbivorous, predatory, scavenging, symbiotic and parasitic species. + Predatory insects and arachnids mainly hunt other insects; thus, overall, the group may be considered mainly herbivorous (> 95%). + Some parasitic species, such as ticks and mosquitoes, derive a significant part of their nutrition from birds and mammals (< 5% overall). * Plants and fungi: + Autotrophs / detritivores, obtain their energy and nutrients from sunlight and/or from waste and remains of other organisms. + A few species in nutrient-scarce habitats may catch insects for extra nutrients (< 1%). Note that I've added a few land herbivores to your ecosystem, since it didn't seem realistic to me not to have any. In particular, if you want large apex predators, you really do need some large prey that they can hunt efficiently; without those, there probably would not be any niche for predators much larger than your falcons. Now, since you've already decided how many apex predators you want, you can start from the top and work out how much food they need. So, for example, three apex predators (3 × 100 kg = 300 kg) will, by the 10% rule, need around 3,000 kg of prey. Around 80% of that will be mountain goats, so that's 2,400 kg / 50 kg = 48 goats; let's round that up to 50. (Nothing else really eats goats in this ecosystem, so we don't need to account for other predators.) That's not a huge lot of goats, but then, three apex predators is quite a small population in itself. The apex predators also eat some lemmings; the 10% rule says we need 450 kg / 0.1 kg = 4,500 lemmings to satisfy their craving for small furry snacks. However, the lemming population is also harvested by falcons; we haven't yet decided how many falcons there should be, since falcons are not a major food source for anything, but let's say there are 100 falcons, making their total biomass 20 kg. They'll thus need 200 kg of prey, of which 75% will be lemmings, giving us a total lemming biomass of 450 kg + 150 kg = 600 kg, and thus a typical population of 6,000 lemmings. (Of course, if these are anything like real lemmings, their population size will be cyclic, growing over a few years to a peak and then crashing. This will likely induce a similar cycle in the falcon population, or at least in their offspring production rate. During peak years, the apex predators may also consume a significantly higher proportion of lemmings, since they'll be plentiful and easy to catch.) The apex predators and falcons will also require a songbird biomass of 150 kg + 50 kg = 200 kg, giving us a population of around 10,000 songbirds. Half of the songbirds' food will be insects, which means they'll need around 1 tonne of insects to support them; however, the lemmings also eat some insects, pushing the total insect biomass needed to support both populations to around 1.6 tonnes. (In practice, the real insect biomass should almost certainly be higher, since some of it will be consumed by other insects and arachnids. I don't have a good conversion factor for that, so let's just arbitrarily call it 2 tonnes.) The 2.5 tonnes of mountain goats will, by the 10% rule, need 25 tonnes of plants to support them; the lemmings will need about 5.5 tonnes, and the songbirds will need about 1 tonne of fruits and seeds. Treating the 2 tonnes of insect biomass as roughly 100% herbivores means they'll need 20 tonnes of plants to support them (and everything that depends on them), for a total plant biomass of around 50 tonnes. (This figure does not generally include things like tree trunks, which are not easily consumed by herbivores.) We'll thus get the following rough biomass / population figures: * Apex predators: 3 × 100 kg = 300 kg * Mountain goats: 50 × 50 kg = 2,500 kg * Falcons: 100 × 0.2 kg = 20 kg * Lemmings: 6,000 × 0.1 kg = 600 kg (typical) * Songbirds: 10,000 × 0.02 kg = 200 kg * Insects: 2 tonnes * Plants: 50 tonnes (live tissue; not including tree trunks etc.) As noted above, if the lemming population is anything like in the real world, it may cycle strongly, from, say, 600 to 60,000 individuals. This oscillation is likely to be reflected, to varying degrees (and with varying delays) in the other populations as well. These cyclic interactions can get quite complex. For example, during peak lemming years, the apex predators may hunt less goats, which will allow the goat population to rise next year; however, the lemmings will also compete with the goats for food, which may somewhat moderate the rise. If the lemmings deplete the plant resources considerably on peak years, this may cause the goat population to first peak (due to reduced predation) on the next year, and then crash (due to lack of food) afterwards. Similarly, a lot of lemmings means that falcons will hunt fewer songbirds this year, but also that there will be more falcons next year. In any case, all of this is assuming an essentially closed ecosystem. However, in nature, few ecosystems are totally isolated from their surroundings, so there will likely be migration and other interactions with surrounding areas. Fortunately, these interactions often tend to be stabilizing: for example, if there aren't enough songbirds and lemmings around, the falcons can fly off the mountain and look for prey elsewhere. In particular, a population of three apex predators is not anywhere near stable in isolation; unless rescued by immigration from elsewhere, it will almost surely go extinct within a few generations (and even if it did not, it would suffer greatly from inbreeding). However, a population of three large predators can live just fine on a mountain, as long as there are other populations nearby from which new individuals can occasionally immigrate, and to which the offspring of the current population can emigrate if there's not enough local prey to support them. [Answer] There will be no exact answer, because it somewhat depends on the life-style of your predator, The [osprey](https://en.wikipedia.org/wiki/Osprey) is a bird of prey that eats fish. They weigh about 0.9 - 2.1 kg. An [osprey eats](http://cfwep.blogspot.com/2008/04/how-much-fish-does-fish-hawk-eat-osprey.html) about 3 kg a day. So about 1.5 times its own weight, depending on what it can catch, as well as how far it is from the food source and whether or not it has chicks. A peregrine falcon is another bird of prey, which [eats](http://diet.yukozimo.com/what-do-falcons-eat/) about 185g ([average weight](http://www.allaboutbirds.org/guide/California_Quail/lifehistory) of a quail) a day. The peregrine falcon [weighs](http://en.wikipedia.org/wiki/Peregrine_Falcon) an average of 915 grams, but they can eat up to birds the size of [2000 g](http://falconsbarcelona.net/Falco11/en_pagines/especie7.html). This shows that birds of prey can have a wide variance in the amount of food they eat. But generally they eat about 1/5 their weight a day. Red tail hawks [weigh](http://animalstime.com/red-tailed-hawk-facts-kids-red-tailed-hawk-diet-habitat/) about 1,030 grams and eat about 135 grams. So they eat a little more than 1/10 their weight. For all of these species the babies eat more. Overall this shows evidence shows that animals eat significantly less per day than they weigh. So an apex predator could eat a large range of amounts of foods. We will go with about 1/5 their weight, because they are eating other birds, and so we will compare them more to the falcon, which is in between the hawk and the osprey. If this is the case, then an apex predator would need to eat about 20 kg of hawks a day. Multiply this by three of three predators, then you get 60 kg a day. That's about 1800 kg of hawks a month. If hawks eat one tenth their weight a day, then you need 180 kg of small birds a month. These are the numbers of birds that will be consumed, not the number of the population, just to make that clear. [Answer] A good rule of thumb is that at each step of the food chain, 90% of the energy is lost: a plant only absorbs 10% of the sunlight that falls on it, of which only 10% is available to a grazing animal, of which only 10% is available to a predator, and so on. Weight is a reasonable proxy for energy, so a 100 kg apex predator will need 1000 kg of hawks, and at the base, you're looking at about 1,000,000 kg of plants. ]
[Question] [ As part II of anatomically correct myths here we have the Angel. Angels appear in many cultures and are most commonly seen as simply winged humans. Is there a realistic way that angels could evolve? Using earth or near earth biology how close could I get to the classic [Angel](https://en.wikipedia.org/wiki/Angel)? Is there a reason that a Angel couldn't evolve? I imagine that this one will be very hard to justify, so any primate with wings can count as an Angel not just humans. A list of all of the Anatomically Correct questions can be found here: <http://meta.worldbuilding.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798> [Answer] If you mean how you can create anatomically correct models of flying humans, then this question can be scientifically and rationally answered. However if you are asking the anatomy of an angel, you are asking an absurd question. You are trying to judge something which is not scientific, under scientific rules. Here I will go on to explain how can you create (in a novel of course) flying humans. ## A - Skeletal Structure You are going to need a very very very light skeleton. That's a prerequisite. We are talking about extremely hollow bones here. At least bird-grade bones or better yet, if you can get pterosaur-grade bones. Pterosaurs were those huge flying monsters that ruled the skies in the times of dinosaurs. Their bones were extremely lightweight. A huge pterosaur (3 times the size of a human) would have bones completely hollow and no more than 1 mm thick. Yeah, now we are talking. ## B - Wings If you examine any flying creature you will find out that their width is greater than their length. That is, you open up their wings, the wingspan will be greater than their length. So a human with 6 ft height would have a wingspan of at least 11 feet when the wings are fully open. Of course the human will fold the wings and keep them on their back just like birds, when not in use. The next issue is the wing surface area. Are you going to opt for membranous wings (like pterosaurs or bats), crustacean wings (membranous, but different type, ones you see on insects) or feather wings (self explanatory, all bird wings are these types)? I think crustacean wings are not an option as they cannot take high air pressure and would tear open quickly. Bird feathers are very strong and offer the best air-thrust method, but they are also heavy. Yes! For the scale of human flight, bird feather WOULD be heavy. If you want to use bird feathers for human flight, the shoulder muscles would have to be really really powerful. In case of membranous wings (bat/pterosaur grade), these are relatively light and you can make do with lesser shoulder muscles. ## C - Flight Muscle Attachment Points If you want your flying humans to have wings AND arms separately, then things could get slightly complicated. You are going to have to form muscle attachment points for the wing muscles. These have to have an anchor point on the chest region, like all birds and pterosaurs. So your flying humans are going to have really really stocky and strong chests. ## D - Flight Posture How are your flying humans going to look like, in mid-flight? Are they going to fly in horizontal body posture (like most birds) or vertical posture (the way they stand, looking somewhat like a hovering humming bird)? I cannot answer this myself as it involves a lot of complex aerodynamics, but I *think* a horizontal flight posture is more likely. [Answer] I think the question is could a six-limbed (2 arms, 2 legs, 2 feathered wings) flying humanoid evolve naturally on an Earthlike planet. The answer, I think, is yes\. I don't think the end result would look much like a human though. ## Environment Environmentally, I think that you'd probably be looking at a near earth-sized moon orbiting a gas giant, heated by relatively mild tidal forces. Lots of volcanoes, quakes, new landmasses erupting out of the ocean, tsunamis, etc. etc. I would also expect that gravity is a bit weaker, and the atmosphere a bit thicker with a noticeably higher oxygen content. That would mean you've got a little more room to play with in body size, but they wouldn't be able to fly on Earth. The key is that I would expect six-limbed life to be common in charismatic megafauna. Basically, I'd expect stuff analogous to centaurs, lammasu, sphinxes, and dragons (not large ones, obviously) to be fairly common on that world. The obvious advantage to flight on this world is that it allows them to escape the disasters much easier, and colonize new land masses very quickly. ## Physicality As I understand it, the main body engineering issue with powered flight is the ratio of surface area to volume/mass to propulsion. To get moving you need propulsion, to stay aloft you need a huge surface area with a narrow profile compared to your volume/mass, but the bigger your surface area, the more mass you have. The more mass you have, the more propulsion you need and the more surface area you need, which costs more mass... and basically the bigger you get, the greater the difficulty in powered flight. I would expect that each wing is about as long as their body. So if they're about 5 feet tall, I would expect a wingspan of about 10 feet, before any feathers. Feathers would probably add another 2 feet in length on each wing, giving them a functional wing span of 14 feet. I would expect that their manipulating limbs, the ones that look like our arms, to be quite short. I'd guess their fingertips would touch their hip bone. Their resting position for the arms would probably be curled up to their chest, like bird legs. I would also expect that their legs would perform much the same function as a bird's tail, and thus have a rather impressive amount of plumage. Their feet would almost certainly be more like a hawk or an owl's feet, with a larger central "ankle" area and stubbier toes- no talons though. I imagine that they'd stand primarily on their toes. Their face would probably look a lot like a canine's, but with larger eyes, smaller ears, and a much larger brain pan. I'd also imagine that their entire body has some form of feathers covering it. ## Biology They'd need a huge heart, massive wing muscles, hollow bones, and very very efficient lungs, even with the higher oxygen percentage in the atmosphere. They'd fly like vultures or geese, which would help them save energy. They'd need to be primarily carnivorous, to fuel their metabolism, but I could also see them going after seeds and other high-calorie forms of sustenance. I suspect that you'd see a lot of similar adaptations to birds on earth, with their red blood cells having nuclei and able to see into the ultraviolet. Heck, these 'angels' would either be like birds, and lay eggs, or be like marsupials, and have a stretchy pouch for their partially developed babies. I doubt they'd give birth the way a human does. If they're tool users, I'd imagine nets to be their primary tool for hunting. In the air, I'd expect lances, bolas, or javelins. They may also have something like a knuckle or a spike on their wings, which would allow them to use their enormous wing strength to defend themselves on the ground. So basically, you'd end up with something more akin to nightmare fuel than angels if you tried to engineer a biologically successful hexapodal flying creature. [Answer] Couple thoughts on this... 1. Angels aren't bred.* Meaning, they don't have to mate, have baby angels, evolve, etc. Instead angels are designed and created, like robots, genetically engineered clones, or something, to be servants for God and to perform tasks; be messengers, be protectors, etc. This doesn't mean they are unthinking machines, and can still have sentience and will to a point. Sort of a weak AI. 2. Angels aren't confined to 3 dimensions. By existing outside of the 3 dimensions our senses can perceive, angels are able to move unseen, pass through (around, over) physical objects and barriers, and do the other things that angels do, while still being able to interact with our perceived dimension as they need to in order to fulfill duties. The best way to picture this is with Flatland. If our world was Flatland, we would see a wall as a barrier that can't be passed through without going through a doorway. But an angel existing in 3 dimensions could "rise above" the flat plain and go "over" the wall. Any angels above the two dimensional plain would be undetectable by any flat instruments since they are unable to look outside of their dimension, but any angel wanting to interact with Flatland would only need to descend or reach down into the plain, or even hover just above it and whisper into your ear (or subconscious). The book [Spaceland by Rudy Rucker](https://en.wikipedia.org/wiki/Spaceland_(novel)) has a lot of similar ideas, where a being living in a fourth dimension interacts with our 3D world. [Answer] A biggest problem here is that a classical angel cannot fly with classical angelic wings. They are just too small. A hand glider gives a rough idea what wings are required to have a human airborne. And, obviously, nobody can really flap such wings. If you are OK with flyless angels, the sexual selection can go long way developing purely decorative appendages. [Answer] The first question to ask is how do they get wings in the first place? There are three ways i can think of this occurring from a realistic standpoint. 1) All land animals evolved from a being with 6 limbs, Two of which became wings 2) An evolutionary ancestor had an adaptation which later became wings 3) Wings are technologically grafted onto the creature/added to their DNA and over time adaptations occur which help support them. Well, 1 is in my opinion the boring solution so i won't cover that, and 3 requires them to be both technologically advanced enough to graph wings (biological or mechanical) and have a valid enough reason to want wings in the first place. So i'll be exploring 2. Now, for my own ideas i decided to look into the mammalian evoltionary tree. Initially i planned on having a mammalian ancestor gain a neutral mutation (one that doesn't positively or negatively affect their chance of survival) but then i came across Pelycosaurs (early, mammal-like reptiles). More specifically, Sail-Backed Pelycosaurs. and i though to myself 'Now If i just added a second sail, these would be an ideal base to give mammals wings'. So i looked into other animals (most extinct) who had two fin-like or sail-like structures going down their back, and hey presto i found one (i cant remember its name at the moment however). So, having two sail-like wing stuctures are possible in reality. From here the question becomes Why do they have these structures? and why keep them? Well, when in doubt about creating a certain adaptation or stucture, unless it gives them severe physical issues, have 'Mating Displays' be the reason it exists. A way to showoff that X creature is tougher and more powerful, and therefore able to produce offspring that is more likely to survive. Ok, we have the How and the Why. Now to decide how they become used for flight and what appearance they will take, Will they be used to showcase how high X can jump? Will they be useful in catching prey? Will X use them to increase the distance they can jump/glide?. What will they look like? Fully fused, Feathered and bird-like? Made of a thin membrane like a bats? a little hairy like a pterosaur? or structured like an insect's wings? Now other things to consider with this approach: what adaptations do you want them to have? Now, if you want them to be basically like a human, just with wings, then the creature they descend from needs to have been a climber at some point -> This is so dexterous, grasping 'hands' can form, allowing for complex tool use and creation. If they are bipedal, then there likewise needs to be a reason to which bipedalism is necessary and practical. Lots of little things (if you want to get hugely in depth about it) that are mainly covered by the topics above. Most of this came from my own exploration into the topic of 'humanoid beings with wings' but there are likely other possible answers as well. [Answer] As an addition to @Youstay Igo because a comment wouldn't work: ## Evolution of an Angel: One of the few ways I can see an Angel-like creature starting to appear, is in a type of polynesian archipelago with lots of vulcanic features as well as hard to traverse terrain on the islands. At first the proto-angels that evolve will start using simple tools. If most of the islands lack treewood capable of sustaining good boats, for example because the wood is heavier than water (not sure if possible in that climate), then a large portion would need to swim to colonize other islands and perhaps survive off the fish and sea-fruit they eat there. Recently scientists discovered that mankind is still evolving, with one "species" of human living so exclusively in (shallow) waters that they have trouble walking on land and adapt to the water well with genetic mutations that support their lifestyle. This evolution isn't unheard of, as Dolphins and Whales are thought to have been land mammals that returned to the water. Now take this evolution further: They will retain their arms and hands to keep using the simple tools they have access to, but need to develop easier ways to swim. They won't just evolve flaps between their fingers, but their shoulderblades could create extrusions to form a crude type of fins, which will later evolve to have musculature for easier steering in water and the basics of "flight" under water like Pinguins who "fly" under water. These fins would become the precursor to wings. As the evolution goes on and more and more of the islands in the area become inhabited, some of these proto-angels will need to start moving inland for food and sustenance. Whether it be predators they try to escape from by climbing trees ASAP or having to scale and jump across dangerous terrain, those fins could start to evolve to support jumping into the tree's and over the terrain, evolving the proto-angels to create a lighter skeleton and more musculature for their proto-wings. Because they are still tool-using creatures and the islands will eventually start evolving wildlife and plantlife that is suitable for intelligent life to start using, intelligence will start becoming a larger part and their arms will also start evolving, without devolving the wings necessary to remain capable across the islands. In fact, the first truly flying angels would be able to scout out islands, settle them and benefit from any foodsources far better than any other proto-angel that came before. The intelligence could also be the defense mechanism to the predators that stalk the thinner and lighter skeleton Angels. This could be the method to Angel evolution. ## How would an Angel be build up? Birds have wings that are attached to the torso with truly massive muscles compared to the rest of the bird. These wings would need to use a kinematic chain similar to humans do when jumping. This kinematic chain would connect the arm musculature to the wings and allow strength from the chest muscles to be passed through to the wings. This would mean that the arms would have a lower movement range to compensate. Materials wise, the Angel is likely in need of some special stuff. Besides a bird-based lung system and a ridgid chest, it would need some special stuff to keep light and strong. For example, by making all ligaments spidersilk-based you can reduce the amount required and thus the mass, and bones would need to be some carbon-enhanced material such as incorporating Carbon Nanotubes into the normal bones for extra lightweight strength. Spidersilk based products might also be the option for the surface area of the wings, if you like the feather aestetic the feathers themselves could use spidersilk to remain light, thin and still strong. [Answer] The average human is 165 cm tall and 62 kg. The angel's bones will be hollow, which should reduce its weight by about 10%, so it will weight 55.8 kg. I am going to be basing the wings off of a [golden eagle](https://en.wikipedia.org/wiki/Golden_eagle)'s. A golden eagle has a wing loading of 7.08 kg/m², in order to get an angel to fly, it would need wings with an area of 7.88 m². Since a golden eagle has a wingspan of 2 m and a wing area of 0.65 m², the angel's wings need to be 12.12 times the surface area and 3.48 times the length, giving a wingspan of 6.96 m, or 22.8 ft. Using the same method with various other birds gives a wingspan of 6.54-12.89 m, a wing area of 6.12-21.26 m², and a wing loading of 2.625-9.12 kg/m². But we're going to stick with our 6.96 m golden eagle angel. <https://www.pnas.org/content/pnas/104/30/12398.full.pdf> Now that we have the size figured out, let's focus on the actual anatomy. In order to fly properly, our angel will need a keel attached to a large barrel-shaped ribcage. It will also need very large, very powerful pectoral muscles. These should be directly attached to the bases of the wings, so the angel will have to be armless (hexapodal vertebrates are not very plausible anyways) the arms having instead been modified into the wings. It would also need very large, very efficient, perhaps bird-like lungs to provide oxygen to its huge flight muscles. So our angel is a 5'5", 123 lb armless human with a 23 foot wingspan. [Answer] Considering that a canonical angel of most religions is not as much a winged human as an energy being capable of manifesting to human witnesses, the issue of their anatomy and physiology becomes a moot point. I would propose that what human eye perceives as wings could be the two overlapping cocoon-like energy fields with a humanoid silhouette in the middle, thus, an illusion of a winged human. As far as evolution of such beings, it's up to the author, since we're talking about creatures evolved far beyond their material body. ]
[Question] [ This might be more fit in physicsSE, but since I don't even know if my premise is physically sound, I'll post it here. --- One day, something caused the universe to get mirrored, meaning a left-right swap, relative to any arbitrary view point. Let's ignore how this is done, how it's possible to move things over more distance than the observable universe in an instant etc., I only care about before and after. The laws of physics are not affected by this, it's just a change in location and orientation for all particles, energy and so on. Let's say you already suspected that this might happen one day (for whatever reason), so you're regularly doing some kind of test that should change its result after the universe got mirrored. What kind of test could this be? What kind of experiment would give a different result in a mirrored universe? My own ideas so far: * Of course you wouldn't just see everything being mirrored, since your eyes, brain and so on also got mirrored. * There are some molecules that only work the way they do in one orientation and not if mirrored, but in the mirrored universe, everything they react with would be mirrored as well, so there should be no difference. * There is the Lorentz force which can create a circular electric field (or was it magnetic?) from a straight motion, but it goes the opposite direction when the charge is opposite. This might be a good candidate. Is enough known about electrons and other charged particles to know whether they would get an opposite charge if they got mirrored? I know that there is always an anti-particle with opposite charge, maybe that is exactly this? I've also heard about theories that this means that it travels backwards in time, but I haven't looked much into that so far. Could this reverse time travel (if that's even what it is) cause some side effects if the universe is mirrored? Related questions: I've seen some questions that ask about interactions between a normal and a mirrored universe, the answers to those always come down to doing something on the border. In my case, there is no such border, except in time. And you can't do experiments in an infinitesimally short timespan. [Answer] In physics mirror symmetry is called [parity](https://en.wikipedia.org/wiki/Parity_(physics)), so the question is whether any of the fundamental interactions depend on the parity. It turns out that the electromagnetic and strong interactions do not depend on the parity, but the weak force does. In fact parity is maximally violated by the weak interaction - only left handed particles and right handed antiparticles interact via the weak force and their mirror images (right handed particles/left handed antiparticles) do not. In everyday life this is not going to make any detectable difference, but the difference is easily measured and indeed this was first done over six decades ago by the [Wu experiment](https://en.wikipedia.org/wiki/Wu_experiment). [Answer] This answer is supplementary to [Rennie's answer.](https://worldbuilding.stackexchange.com/a/135952/10324) I try to explain the long discussion in the comments to that answer. The problem is defining what is meant by mirroring. In your question you end your description with "and so on". Depending on what is included here the situation changes. For more discussion of this, you can look up ["CP violation" on Wikipedia](https://en.wikipedia.org/wiki/CP_violation) or other places. The basic question is "What is the mirror image of an elementary particle like the electron?" If you answer "just an electron", then Rennie gave the right answer: Wu discovered in 1956 that certain things are different in such a mirror. If you answer "a positron (anti-electron)", then things look more similar in the mirror, but it turns out that there are still differences. This was discovered in 1964 by Cronin and Fitch. If you answer "a positron going backwards in time" there are currently no known experiments that can tell the difference, but we don't really know. Maybe, just maybe, there might be an obscure difference somewhere. I assume you didn't mean to include time reversal in your mirroring, and if so there there are experiments you can do. As the World-Builder, you have to decide which type of mirroring you want and thereby which experiment is needed. [Answer] There is no way of telling. If everything is mirrored, then the means to detect changes are also mirrored. The left-handed particles are now right-handed. But your understanding of left and right have also switched. So even though there is a switch in the handedness of particles, the mirrored-left particle still corresponds with your mirrored-left hand. You look in a text book to check. But instead of the particle looking left handed, it looks right handed, which confirms that everything is "normal". [Answer] I don't possibly see how there could be a scientific, empirical way of telling. If everything is swapped, so are the means to measure it. For all intents and purposes, you could have swapped the definition of right and left. And while the [Wu Experiment](https://en.wikipedia.org/wiki/Wu_experiment) seems to have proved that a mirror image would be distinguishable, if everything was reflected, would that not include the (previously) left-handedness of the neutrinos and the right-handedness of the anti neutrinos? Really it depends on the OP definition of "everything," and in the end it would really be determined by how this relates to the scenario the world-building is for. [Answer] Well, I was left handed yesterday, but somehow that changed. Pseudo vectors are an excellent way of describing what you want. If all the coordinate axes of a system are inverted, a pseudo vector pics up a negative sign. From wikipedia "(A pseudo vector)is a quantity that transforms like a vector under a proper rotation, but in three dimensions gains an additional sign flip under an improper rotation such as a reflection." Lorentz forces are a good example of pseudo vectors. This is as a result of the cross product involved in the equation. A cross product is a pseudo vector if both its inputs are of the same type (E.g. both vectors or both pesudo vectors) and a polar vector if they are different. If electromagnetism is not something you'd like to use, consider angular momentum and torque. For example, the vector of precession torque of a spinning disk or top might cause a clockwise precession of a top which was given a counter-clockwise angular velocity (looking from above) if the coordinates of the entire universe were flipped. (If the universe hasn't been flipped, you would see counter-clockwise precession as expected) See <http://hyperphysics.phy-astr.gsu.edu/hbase/top.html> for more. Also, if said top never stops spinning, you're dreaming or in limbo. Wake up neo, you're in the matrix. Perhaps someone else can verify this as well, but I believe any physical phenomenon described by at least one polar vector and at least one pseudo vector would be useful as an indicator of the flipping of the universe. (Otherwise, if they were all the same you'd see them ALL picking up the flipped sign and then it would cancel with the flipping of the universe) ]
[Question] [ Our intrepid hero works in an open office, within a short stone's throw of the IT Support Desk. They fool around every Friday (and most days between Friday and the following Thursday). The inane chatter and laughter is annoying and disruptive. How can our intrepid hero create a hand-thrown silence grenade over the weekend? Constraints: * Area of effect should be 10 m$^2$ * Despite calling it a grenade it need not explode in the traditional sense * Should incapacitate those in the blast radius for ~ 8 hours * Fits in the palm of the hand and can be easily activated and thrown * Should have a delay mechanism...I don't want to knock myself out * Cannot be fatal/cause long term damage (I hear prison is pretty loud too) * Should not require any ridiculous future tech or military grade components * Works. Desired Effect: Silence until 4:30pm at least. [Answer] Creating silence is a tough ask. I think the best way to approach this is to fill the space in your office with something sound dampening. In that case, what better approach than expanding, sticky, [riot foam](https://www.defensetech.org/2006/03/07/sticky-foam-gets-serious/)? [![enter image description here](https://i.stack.imgur.com/6Uj5j.jpg)](https://i.stack.imgur.com/6Uj5j.jpg) Evidently the stuff [isn't that expensive](http://www.screwfix.com/p/no-nonsense-expanding-sticky-foam-gun-grade-750ml/6576h), and if you can build grenades in your garage over the weekend, you are probably mad-genius enough to pack that aerosol into a tighter space. Toss a few of those babies in the corridors in each direction from you to dissuade nuisances, and then pop a few more on top of the nearby cubicles. Wait and listen as the noises die down...after a brief bout of shouting and confusion. As an added bonus, if you gum up your boss he can't hassle you any more for the rest of the day. As a downside, the SWAT team probably will. [Answer] Sorry gents! Simply knocking people out won't work because that fat ba\\\rd, Ted, at the accounting desk snores like an elephant in heat. What we really need is active noise cancellation. Thankfully, this already exists: <http://id2studio.at/content/noise/>. Tossing one of these on each office window would/should effectively cancel everyone's sounds. It won't knock the loud mouthed goof-offs out, but your stated goal is silence, not jail-time. ps - Here's a video demonstration: <https://player.vimeo.com/video/71085920> And Sono isn't the only one. There's also [Muzo](https://www.youtube.com/watch?v=bZGJbC1Yb1g) and [Whisper](https://www.youtube.com/watch?v=-pzdn0Dtd2U). [Answer] Sound can be cancelled by applying additional sound waves that cancel out existing sound waves and cause the vibrations that carry sound to flatten out. This is how sound-cancelling headphones work. However, there is a kickstarter campaign I heard about for something called the "Muzo", which is essentially a sound-cancelling speaker that operates on the same principle. You can stick it to your window to silence the street, to your desk to keep coworkers from hearing your computer activities, or stick it in the middle of your table at a restaurant to keep your conversations more private. I imagine that discretely placing a few of these around where you would expect the offending coworkers to be when they are making a ruckus could potentially effectively silence them and cause all sorts of hilarious disruption as you wirelessly activate and deactivate them at your pleasure. This doesn't incapacitate anyone and can't be thrown, but it can be discretely planted in key locations where it would be unlikely to be found. Note that some people are driven nuts by complete silence and they need a little background sound in order to function normally. With a collection of a high-powered version of these speakers placed strategically around a target area, you may even be able to prevent your offenders from even hearing themselves, driving them mad and causing all sorts of hilarity. [Answer] Organize an off-site meeting without going to the meeting. You may need to obtain official-looking letterhead from the boss, CEO, or someone higher-up who isn't going to be in close contact with this group; if he intercepts the grenade, it's a dud. The stack of physical invitations may require two hands (breaking your constraint), but I think you'll manage. Depending on the number of interns available to you, "throwing" this grenade can take some time, but people will most likely believe a distributed letter over an email. * Speaking of which, you can go the digital route. Deployment logistics are reduced significantly and you can even schedule an automated delivery, but the interception vulnerability is greater due to the ease and immediacy of replying to an email. Plus, you can add an "emergency" constraint to throw this grenade whenever you want, which simplifies the location selection process. * And this brings us to picking the location. If the meeting is scheduled during work hours, the location should be at least 4 hours away (if people are to leave from the office) or 8 hours away (if people are leaving from home) from the office. This will ensure that everyone will get to the location and not be able to get back to the office by 4:30. * Luckily, having the grenade working more than once was not in your constraints. If word gets back to the scapegoat planner, this could be a one-time use only. However, it could also be everyone's little secret to take a scheduled day off at a Chuck E. Cheese's each year. [Answer] Sleeping gas grenade [Sleeping gases](https://en.wikipedia.org/wiki/Sleeping_gas?wprov=sfla1) can be nasty but basically take the stuff the dentist or doctor use to render patients unconscious for surgery and add it to an air tight container. You will probably need to add quite a bit since the people in question won't have a mask over their face forcing them to inhale. For the delay you could go with a timed trigger with a mechanical opening or if you don't feel the need to be fancy it could be a wax sealed container with a wick like a smoke bomb, wick melts the wax, the gas under pressure escapes. Drawbacks of this plan. * Controlling the radius is going to be difficult (ideally you would use this in a closed room) * I am not sure what concentration of gas is required to knock someone out (and I am not googling that at work) * They will only be unconscious for a while, not the whole day, but when they come to they will feel like crap which should keep the shenanigans to a minimum [Answer] You don't need a grenade. A grenade goes BOOM. What you need is carefully designed architecture. What you need is an [instant anechoic](https://en.wikipedia.org/wiki/Anechoic_chamber) chamber - self assembling nanobots, that hopefully will cover the walls in spikes of soft, sound absorbing material, without, hopefully covering the co-workers in said material, resulting in a slow, quiet, painful death, Or a less instant one with sound absorbing spikes on the walls. Since the room's topology is known, you could, in theory back this up with active noise cancelling systems. If you felt particularly evil (and didn't want to accidentally kill a few noisy co-workers , or add foam spikes to the walls manually), there's directional speakers on the market that you can use to beam the sound of people in the room to themselves... with a slight delay, which supposedly confuses people so they can't talk. They will go quiet eventually. [Answer] Hmm ... I think perhaps you're approaching the problem from the wrong angle. Instead of building something exotic to cancel sound waves, you need to build something simple to cancel your coworkers' desire to chatter all the time. First thought. One of these: [![hand grenade](https://i.stack.imgur.com/tTI8t.png)](https://i.stack.imgur.com/tTI8t.png) Remove the pin, put it up on a cubicle wall, and warn co-workers that excessive vibrations in the air might set it off. You might ... acquire a reputation for being psychotically volatile, but hey. Peace and quiet is important too, why can't those fools see that? Second thought. Get one of those bullhorns-in-a-can. Rig it to a volume-sensing machine. When it gets too noisy, it releases an annoying blare. Over time, Pavlovian (well, we're edging up on Skinnerian) conditioning will induce lovely silence in your coworkers. Third thought. Set up one of those parabolic listening antennas. Live-stream their chatter to the Internet. This should have an inhibiting effect. (Warning: if there are amateur thespians in the crew, this could backfire, badly) Final thought. This may seem trite and silly, but you could, like, ask them to pipe down...? [Answer] Making The Grenade If you must create a grenade for your purpose, then here is one. It will help you a lot in silencing down people, but you will have to use some sabotage and social networking skills to put it into action. First, go to a hypno-therapist (perhaps without the dashes) and get a recording of his/her session for persuading the subject to go on a riot. Next, go to a electronic store and get several simple mp3 players in the shape of a grenade. Copy the hypno-therapist's session audio into your grenades and take them to your office. Fire In The Hole! At the desired time, quietly slip one into the waste bin of the desks where most of the noise is coming from. Now barricade yourself in the bathroom with the most attractive coworker of the opposite gender for the next 2 hours as the magic happens and all the noise escalates into an office-wide riot. Your boss will quickly fire all those noisy, rioting folk the next day. Make sure to remove your grenades the same day. If the new folk continue to be noisy, rinse and repeat until you get a batch of really quiet IT guys! [Answer] Etymotic Research ER20 ETYPlug<http://amzn.to/2cBbkmp> "Constructed of comfortable soft plastic, these earplugs are capable of much more. With a hearing attenuation of up to 20dB, they are perfect for industrial workers or anyone who regularly experiences high degrees of noise" The product description says it all. They fit in your palm, and once you "throw" these silencers on, the sound canceling "incapacitation" begins immediately. They operate under fully time-controlled use at your whim, however, you WILL also be affected in that your own noise production will be within the"blast" zone. No special tech or military grade materials required. They work. [Answer] Grenade plays simulacrum of the office's fire alarm. Protagonist locks doors once everyone leaves. Grenade releases horrifically foul smelling odour. ]
[Question] [ Taking into account a medieval-ish lifestyle, one of the most important things, I would imagine, correct me if I am wrong, is food. If you could eat food, you were probably also not poor. Now, imagine a kingdom, such as the [one depicted here](https://worldbuilding.stackexchange.com/questions/10218/horses-for-absolutely-everybody-how-it-came-to-be), with the presence of a special grasstato plant, that is grass above ground, with a potato tuber underground. This special plant can only grow in this certain kingdom, due to magical reasons, but it grows really fast, with no maintenance needed. It grows all over the place, like a weed. Another thing to note is that the harvested grasstato has an extreme acquired taste, so foreigners really do no like the taste of it, to the point of being thought as poisonous, while everybody in the kingdom is probably fed since birth with it. The consequence of that would be that food will be very plentiful, even a homeless crippled begger could pull a grasstato out of the ground and eat it raw. This means that nobody would be starving to death. If food was this plentiful, what would poverty stricken life be like? [Answer] Let's take a look at [Maslow's hierarchy of needs](http://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs). Although obsolete according to newer psychological research, it is still a useful model for storywriting: [![Pyramid showing Maslow's hierarchy of needs](https://i.stack.imgur.com/3Ta6o.jpg)](https://i.stack.imgur.com/3Ta6o.jpg) The quality of life of a person can be estimated by looking at which level of the need pyramid is fulfilled. As you can see there is a lot more than just food which makes a person's life worth living. Looking at the lowest layer (physiological needs) the need for food would be satisfied. Water too, when there is a source of clean drinking water available. But what about the need for warmth and rest? Poor people will still need a shelter, clothes and heating to not suffer from inclement weather and even freeze to death during the winter. Also, eating only grasstato would be a stigma of the poor. For the middle-class, the grasstato would still be the basic food source, but they would differentiate themselves from the lower-class by combining their grasstato with other food sources like fruits, dairy products and meat to have a more varied flavor experience. The upper-class would pride itself in not ever having to eat grasstato. Then we have the safety need. In today's world, the poorest people of most societies perceive the police rather as an additional threat to their personal safety than a protection. Very often, the police are tasked with keeping the homeless out of the more prestigious areas of a city, sometimes with very violent methods. When a homeless beggar gets beaten up and robbed, nobody cares. But when the same happens to a millionaire, the police will do everything they can to hunt down the perpetrator. While you see a policeman at every corner in the better areas of the city, the slums are often crime herds of anarchy ruled by more or less organized criminals who do as they please. The law enforcement has given up about them and tries to contain the criminal activity in the slum instead of fighting it. Does the law enforcement system in your world care about protecting the poor? Or are they even reducing their safety by discriminating against the poor in favor of the rich? Intimate relationships and friends: Poor people will of course have intimate bonds with each other which won't be any less sincere than those between rich people. But social class barriers will be there: higher classes will look down upon lower classes and won't want anything to do with them. Socializing with higher society will be impossible for poor people and having an intimate relationship with someone from the upper class will always be a dream. Sure, not an impossible dream - the Cinderella love story is a very common romance trope - but when exploring such relationships on a level which goes deeper than the average fairy tail or romantic comedy, they will usually suffer from the power difference between the partners and turn out to not have a happy ending after all. On the other hand, a rich person could easily have an affair with any poor person they want. They would just buy them something nice - everyone's dignity has a price, especially when they don't have much dignity to begin with. And when they refuse, they could just take them by force. It's not like anyone would care. At least nobody who has the power to stop them (see safety needs). Esteem needs: The poor people are likely poor because they either are unemployed or work very unpleasant jobs which are menial, dirty and boring. That means they don't have any feeling of prestige or accomplishment in their work-lives. The middle-class who have jobs which require special skills and training (craftspeople, scribes, small-scale merchants...) will experience recognition for their work more or less regularly, and the upper class (landowning nobles, large-scale merchants, high-ranking government officials, famous artists...) will bath in prestige and feeling of accomplishment. Another thing which falls into this category are aesthetic needs like fancy clothes or a pleasing interior decoration in your home. The rich people could afford much nicer things in general. Self-actualization: As said in the previous paragraph, the poor wouldn't get any of this through their work. And with the few resources they have they wouldn't have any left for any creative hobbies. The rich, however, will have enough disposable income and spare time to indulge in any passion they feel interested in, be it an expensive sport, studying an interesting subject, supporting talented artists, changing the world by promoting a new philosophical idea or just amassing even more money and power. [Answer] This super spud is not going to magically make life better, as it was not hunger that killed the most people in medieval times, not by far. Malnutrition, a lack of shelter, a lack of money, a lack of health care or clean water, a lack of safety from bandits or wild animals, a lack of clothing, a lack of somewhere besides the streets to crap and so on. Your magical grass potato is exceedingly unlikely to have every single nutrient a person needs to survive healthily on, after all, so instead of starving of EVERYTHING, you could have to deal with scurvy, protein deficiencies etc etc. Life would be as harsh and miserable as you want it, an easily acquired tuber will not change it. [Answer] Consider the terms [absolute poverty](http://en.wikipedia.org/wiki/Poverty#Absolute_poverty) and [relative poverty](http://en.wikipedia.org/wiki/Poverty#Relative_poverty). Your magical plant will increase agricultural output per capita and help to kick-start an industrial revolution, but it won't make the poor suddenly rich. They'll still live in absolute poverty. * Who owns that "grasstato" field and what does he or she have to say about squatters who steal the harvest? * Could a poor squatter/homesteader build a decent shelter? Even if there are trees for a log cabin, where does the axe come from? * Could the poor find "grasstato" fields where the jobs are, or do they have to choose between a full belly and a few coins for all their other needs? Assuming that there are unclaimed lands, the "grasstato" makes it easier for the poor to live off the land -- at least until winter comes. [Answer] The question describes Star Trek, where there is no money and people get food from replicators. No one has to work or be worried. I assume for such a society to function someone must be concerned about something, but we don't know what that is. Current technology is a good example. A rich man and poor man use the same type cell phone. Third world countries have been able to leap-frog forward, using cell phones and not having to lay wires. Technology then, is an equalizer. People become dependent on technology rather than slaves. If there was infinite food we would need to assess that evolutionally. Food is of course a major contributing factor to evolution. If food goes away, what is left? There is still a need to procreate. There is intellectual competition. Probably there would be less violence. According to Steven Pinker and Michael Shermer we have reduced violence in our world today, and it is attributed possibly to the greater abstract or intellectual world we live in compared to physical or medieval times. To reference Steven Pinker please see: <http://stevenpinker.com/publications/better-angels-our-nature> . He's one of my favorite authors and helps dissuade much of the incessant negativity we hear. To reference Michael Shermer see [http://www.amazon.com/The-Moral-Arc-Science-Humanity/dp/0805096914](http://rads.stackoverflow.com/amzn/click/0805096914) , or see Skeptic Magazine at <http://www.skeptic.com/> . [Answer] I have lived below the poverty line. Food was NEVER a problem. Food is cheap. A bag of rice will last you approximately forever. On fifty bucks you can live for three months, and reasonably well. If you can scrape together five bucks a day, you'll find why obesity is a big problem amongst the poor. In the west, you'd still have trouble with bills, though. These bills include but aren't limited to: * Taxation (still an issue in medieval times). * Housing (still an issue). * Health care (all home remedies, for the poor). * Transport (nobody really traveled back then). * Education (hah! No chance). * Water (water was free back then, if you could carry it). * Energy (electric, gas - not around then, but wood was. Free if you could gather it). * Clothing (not a huge deal in warmer climes). Nowadays, most countries provide some or all of these free for everyone, or at least for those below the poverty line. This is what society and government is for: to lift people up to the point where they aren't worrying about merely staying alive and out of debt, and can instead start contributing to society. This is also arguably what a liege-lord should do - he should be a carer and manager for those under him, ensuring that they all at least have a chance to get what they need. Downside is, the higher you raise the bar for "minimum acceptable lifestyle for the lowest earner", the fewer people think it's worth bothering to do more than that. And the more you cap the earnings of the highest fliers, the fewer people think that rising above is worthwhile. So while every government provides some life-support for those unable to cope, the level of support varies wildly. In a medieval setting, you can expect pretty darn low support, but with low population density, a physically able person can probably survive. How would it be different? Well... I reckon it wouldn't be, really, except that famines wouldn't happen. In most temperate areas, most times of the year, there's food enough to live on just by wandering the hedgerows. In very populated or hard-to-farm areas, famines can happen, but they were typically less of a problem than plague or war: that is, famine wasn't a constant existential threat to the poor. I'm not saying people didn't starve through poverty (or that they still don't, even in the West). I'm just saying that I think the difference it would make to society overall is minimal at best. More temperate environments with easier availability of food tend to have higher populations, have larger cities, and to be more advanced than their neighbors both socially and educationally. [Answer] As always, the problem is not the scarcity of food but the social mechanism of control over it. In medieval times, your liege lord owned the land on which the food grew. Peasants lived and worked on the land, and in return were given some of the food they grew, with the lord retaining the rest. Even if your magic potatoe requires no care whatsoever, there is no guarantee you will have access to any. Those who have (or want) power will create artificial scarcity (through taxes, land ownership and selling their surplus supply on the market) as a means of control and enrichment. Your magic potatoe may grow easily, but the local lord will control the supply and will sell it to you, or else make you work for it. The wealth generated through this is profit, which further enriches the owner. This is really no different to how things work under capitalism, except that we've (mostly) eliminated nobility and it's now just about money and ownership. This topic is a great launching point into the economic theory of scarcity and why it exists as well as the historical rise and fall civilisations. The short answer is that every society in history which has developed job specialisation (i.e. past the hunter-gatherer stage and into agriculture) inevitably becomes inequitable, concentrating wealth and power (through control of resources) at the top. If you think about your magic potatoe situation, it's really not all that different to how the world was before the concept of land ownership was developed. Once upon a time, we wandered around, gathering and hunting what we needed. Fast forward to medieval times, and someone owned the land, and simply taking what you needed was "stealing" and you had to work for it. [Answer] There were societies in which this was the situation. For instance, the Tlingit Indians in Alaska had fish (salmon and other), seaweed and other ocean products in such abundance that they could always eat whatever they wanted. This did not mean that other resources were not highly restrained. (Humorously enough, their only agricultural product was tobacco. They didn't bother to domesticate any other plants). [Answer] Unless the Grasstato is a complete food, there are vanishingly few of those by the way, you haven't done all that much to change the poverty equation. Poverty has never really included a lack of food in terms of calories but rather a lack of food nutrients, the staple diet's lack of certain key vitamins and minerals was usually the killer aspect of poverty in medieval Europe. These days it's the same story different the poor eat bad food, too many "empty" calories, too much salt, too much fat, not enough fibre. It's not just poverty that can kill you that way either, historically the Roman elite died of lead poisoning from their water pipes and had their growth stunted by shunning animal protein as unclean and in modern Japan one of the prestige dishes is puffer fish, it's hideously expensive and people get killed by it every year. Back to the Grasstato, having such an abundant staple crop is not without it's uses but there would still be issues of malnutrition because a pure Grasstato diet would have too much and/or too little of certain things in it. A staple that can be grown on very marginal land does free up good cropping land to grow the rest of the bodies' needs, as well as cash crops, in greater abundance and would thus increase the wealth of the kingdom as a whole accordingly. You would probably show a better overall quality of life in compared to the neighbours (at their expense, which wouldn't last long before they felt threatened) but the very poor are still going to be without the material trappings that their countrymen take for granted and very probably still going to be in ill health due to a deficient diet. ]
[Question] [ The praised Dutch book "Koning van Katoren" features an 18 year old who wants to become king of his country of Katoren, which had been under the regency of half a dozen evil ministers for his whole life. The ministers gave him a series of impossible tasks, like curing a plague and cutting down a dangerous pomegranate tree which drops actual grenades. He miraculously succeeded in every task, and the exhausted ministers eventually ordered him to just jump down a church tower. But by this time he has become so popular with the people of his kingdom, that thousands of them travel to the church in question, all carrying their bed pillows. They pile them up high before the tower, and when the boy finally makes the jump, his fall is literally cushioned and he survives without any injury. The tower's height is never stated in the story, but the tallest and most famous church tower in the Netherlands is the [Domtoren](https://nl.wikipedia.org/wiki/Dom_van_Utrecht) at 112 meters tall. Because he did not jump from the actual roof, but rather from the highest balcony, let's say he fell 100 meters. How many pillows are needed to cushion his fall and leave him unscathed? A rough order-of-magnitude estimation is fine: I am curious if it would have been closer to a thousand people that showed up, or more like a hundred thousand. [Answer] Okay, from a height of 100 meters, the faller will reach a speed of 44m/s. Human terminal velocity, for a spread-eagle position like skydivers, is 53m/s, so drag is going to play a big role here, especially if he goes spread-eagle. Call it 32 m/s of landing speed. If our hero wants to stop in ten meters from this, assuming roughly constant acceleration, he will stop in 0.625 seconds and will experience a bit over 5g. This is survivable, especially if he goes back-first. I don't know the angle of repose for the pillows that the townspeople are using. Let's just assume that it's 45 degrees, because it makes the math easier. The volume of a cone with a radius and height of 10 meters is just over 1,000 cubic meters, or about half the size of an Olympic swimming pool. That's a lot of pillows. You could reduce this by using the wall of the church to support half a cone. You could get a smaller cone by making it steeper, but that involves binding the pillows together, and you don't want to do that. See, when stunt performers fall onto airbags, the bags vent pressure to slowly catch the performer and prevent bouncing. In the same way, our hero is going to just explode the pillows out as he lands. Accounting for the increased density of the pillows as they stack is difficult, but I doubt the volume of the pillows out of the pile will be more than twice the volume of the pile. This conveniently cancels out the factor of 1/2 that we get from building the stack against the church. 1,000 m3 of pillows. A rough estimate from the pillows on my bed gives about 7-10 pillows/meter. You're talking 7-10,000 pillows in play here, which may not be from the same number of people, since one person can bring multiple pillows to the church. [Answer] Without having the information to crunch numbers on this... I'm going to call it plausible, but only if the commoners have enough knowledge of physics. What you really need is to absorb energy slowly. For this to happen, your pillows will have to be able to "give" a lot, and quickly. Now, the good news is we are presumably talking about down pillows, as opposed to modern stuff, which does have quite a bit of "give", especially if someone knows enough physics to tell the peasants to take out some of the stuffing first. That said, your best bet would be if you can somehow construct the sort of air bag that professional stunt performers use. Failing that, your hero is probably better off jumping into a series of awnings that will rip as he hits them. It's not inconceivable that a bunch of peasants could arrange to erect such structures, though it starts to stretch belief that the evil ministers will just look the other way. Another option (that could be used in addition to all of the above) would be for the hero to hold one or more pillow cases over his head to use as a makeshift parachute. This almost surely wouldn't be enough on its own, but might slow his fall enough in combination with other methods. See also <https://www.reddit.com/r/NoStupidQuestions/comments/8wqy7o>. That said, the one thing that will really help is if the pile of pillows is built against the side of the church to form a slope. This way the pillows are absorbing some of the hero's energy, but they are also working to redirect his downward momentum into sideways momentum. If you can do that over a sufficient distance, you can survive a fall onto concrete (how to avoid friction-related issues is left as an exercise for the reader). If the pile of pillows forms a relatively steep slope against the side of the church, and the hero hits it right, and his clothes don't shred from the friction, I would say it's plausible that, between the friction of sliding down the slope-of-pillows and the cushioning effect of the same, he could survive. --- On the other hand, since the height of the tower isn't known... it might be as little as, say, five stories, if this is a smaller, local church. [Answer] I don't believe he can walk away from this, period. Look at Itmauve's answer--stopping in 10 meters causes 5g of acceleration--done right, this is fine. But can you actually punch 10 meters into a pile of pillows? A quick look in the closet indicates that arranging pillows to make a human-size/shape landing (in a jump you would have extras because you don't have perfect but they aren't hit, they're irrelevant to this) weighs at least 10% of my body weight. That means a stack of 10 pillows will equal my body weight--and at that point I've shed a minimum of half my velocity--in little more than a meter. Survival is questionable, walking away isn't going to happen. Now, you probably can find some fluffier pillows but the effect isn't going to be huge as pillows are engineered for human body weight--a pillow which has too much give is not going to be pleasant to use. For those who aren't getting what I'm saying: While it is not an inelastic collision the end result is functionally the same. The jumper is going 32 m/s, he hits pillows of his own weight moving 0 m/s. The end result is 2x his weight moving 16 m/s--I do not care exactly what the collision looks like, I'm looking at the start and end points and seeing him shed 16 m/s in the space of 1 meter--and that's far above the danger threshold even in an optimum deceleration curve. [Answer] A 100-meter jump would break current world records for free-fall jumps. I do not believe this would be possible with pillows. [Dar Robinson](https://en.wikipedia.org/wiki/Dar_Robinson) currently holds the world record for the highest free-fall jump in a commercial film at 220 ft (67 meters). That's 33 meters short of the church jump. That's with several safety precautions, practice, and training. He also did a 311 feet (95 meter) jump onto an airbag. [Luke Aikins](https://www.npr.org/sections/thetwo-way/2016/07/30/488083554/luke-aikins-becomes-first-person-to-jump-from-a-plane-without-a-parachute) set a record for the highest jump without a parachute at 7,620 meters. He landed in a specially made net, not a pile of pillows. Why I'm doubtful a pile of pillows would allow you to walk away from a 100 meter fall The "airbag" was probably something like [BigAirBag](https://en.wikipedia.org/wiki/BigAirBAG), which has 2 stages. One is a soft stage to slow you down, the second is a firmer stage to stop you. Even with 21st-century technology, we don't do 100 meter falls without a parachute that often. This answer points out that hundreds of years later walking away from a 100-meter fall would still be quite note-worthy, and that even professional stuntmen would likely not attempt this. [Answer] If you want a really quick rule of thumb for things like this, which assumes no air resistance, and an ideal substance absorbing your fall (which produces the same deceleration at all levels of compression) then you can just use potential energy. The kinetic energy gained in the fall is mgH for mass m, acceleration = g, starting height = H. Suppose an object can survive ng deceleration, starting at height h. Then, to come to a stop at ground level, m(ng)h = mgH. Simplifying, this gives h = H/n If you assume that a boy can survive a 10g deceleration, for example, without injury then in your example h = 10. A normal pillow, uncompressed, probably has a height of between 10-20 cm. Assuming the lower height it could be as few as 100 pillows. In practice, of course, that wouldn't be stable so let's assume a triangular based pyramid 100 pillows high. That gives 1/6\100\(100+1)\(100+2) = 171700 pillows. That's quite a large village then. However, if we assumed 50g deceleration (50% survivable for a child based on a mention in <http://www.madsci.org/posts/archives/2003-11/1068660102.Bp.r.html> though I haven't got the original source) and 20cm thick pillows then we need just 10 in height, which would be a pyramid of just 220 pillows. In practice, of course, pillows will not stack well, or decelerate evenly so the answer is definitely much higher than this. In short, the answer is that (a few) thousands is probably enough for survival but hundreds of thousands may be closer to the mark if he is to walk away unscathed. [Answer] there is not enough information given to calculate the number of pillows, like what are the pillows made of and what is their size. and the distance from the jump to where the pillows start, if the stack is 90 meters high then he will not accelerate much before his fall is slowed. given enough of the right pillows it is feasible. [Answer] The physical process of piling up pillows may be a problem. The people will need to pile up the pillows in a pyramid like shape and the process of stacking may determine how stable it the stack is while people are passing pillows up the stack to the top, as well as how well the stack of pillows cushions the protagonist when he jumps. Did you ever hear of the Bent Pyramid? > > The Bent Pyramid is an ancient Egyptian pyramid located at the royal necropolis of Dahshur, approximately 40 kilometres south of Cairo, built under the Old Kingdom Pharaoh Sneferu (c. 2600 BC). A unique example of early pyramid development in Egypt, this was the second pyramid built by Sneferu. > > > The Bent Pyramid rises from the desert at a 54-degree inclination, but the top section (above 47 metres) is built at the shallower angle of 43 degrees, lending the pyramid its very obvious 'bent' appearance.[4] > > > Archaeologists now believe that the Bent Pyramid represents a transitional form between step-sided and smooth-sided pyramids (see Step pyramid). It has been suggested that due to the steepness of the original angle of inclination the structure may have begun to show signs of instability during construction, forcing the builders to adopt a shallower angle to avert the structure's collapse.[5] This theory appears to be borne out by the fact that the adjacent Red Pyramid, built immediately afterwards by the same Pharaoh, was constructed at an angle of 43 degrees from its base. This fact also contradicts the theory that at the initial angle the construction would take too long because Sneferu's death was nearing, so the builders changed the angle to complete the construction in time. In 1974 Kurt Mendelssohn suggested the change of the angle to have been made as a security precaution in reaction to a catastrophic collapse of the Meidum Pyramid while it was still under construction.[6] > > > <https://en.wikipedia.org/wiki/Bent_Pyramid>[1](https://en.wikipedia.org/wiki/Bent_Pyramid) > > > The outer casing and much of the structure of the Maidum Pyramid collapsed sometime during the period of ancient Egypt, possibly while it was still being built. > > The collapse of this pyramid during the reign of Sneferu is the likely reason for the change from 54 to 43 degrees of his second pyramid at Dahshur, the Bent Pyramid.[3](https://www.google.com/search?q=the%20princes%20and%20the%20peaa&oq=the%20princes%20and%20the%20peaa&aqs=chrome..69i57j0l7.6990j0j7&sourceid=chrome&ie=UTF-8) > > > <https://en.wikipedia.org/wiki/Meidum#Pyramid>[2](https://en.wikipedia.org/wiki/Meidum#Pyramid) the Maidum Pyramid is made out of rocks, and yet it collapsed. Obviusly a pyramid made out of soft and flexible pillows would have a much greater tendency to shift and thus collapse and would have to be built much more carefully. You may remember the fairy tale of "The Princess and the Pea": > > The story tells of a prince who wants to marry a princess but is having difficulty finding a suitable wife. Something is always wrong with those he meets and he cannot be certain they are real princesses because they have bad table manners or they are not his type. One stormy night a young woman drenched with rain seeks shelter in the prince's castle. She claims to be a princess, so the prince's mother decides to test their unexpected, unwitting guest by placing a pea in the bed she is offered for the night, covered by huge mattresses and 20 feather-beds. In the morning, the guest tells her hosts that she endured a sleepless night, kept awake by something hard in the bed that she is certain has bruised her. The prince rejoices at her bruised back. A huge wedding takes place in the palace. The prince couldn't believe that he found his true princess. Only a real princess would have the sensitivity to feel a pea through such a quantity of bedding, so the two are married. The story ends with the pea being placed in a museum, where according to the story it can still be seen today unless someone has removed it. > > > <https://www.google.com/search?q=the+princes+and+the+peaa&oq=the+princes+and+the+peaa&aqs=chrome..69i57j0l7.6990j0j7&sourceid=chrome&ie=UTF-8>[3](https://www.google.com/search?q=the%20princes%20and%20the%20peaa&oq=the%20princes%20and%20the%20peaa&aqs=chrome..69i57j0l7.6990j0j7&sourceid=chrome&ie=UTF-8) Recently I did something vaguely similar. I put another mattress on top of my mattress and box spring. And apparently the flexibility of the two mattesses combines to make a somewhat unstable platform which sometimes threatens to slant too much and roll me off the bed. So I wonder about the stability of three mattresses one on top of the other, and four mattresses one on top of the other, and so on. So how stable will ten pillows one on top of the other be, or twenty, or thirty or forty, and so on? If the protagonists needs a pile 200 pillows high to survive his fall, but the pile keeps sliding down and collapsing whenever they try to pile higher than 100 pillows, he will be doomed. In my opinion, the protagonist would be much more likely to survive a jump into a pile of pillows from a ten meter church tower than from a hundred meter tower. And if he lands on a flat topped pyramid (or half pyramid leaning against a church) much more than about ten meters tall, his landing is likely to cause the pyramid of pillows to collapse and spill out and he might get buried by pillows during that collapse and his friends might have to frantically dig him out of the pillows before he suffocates. So I can imagine a story where a technological or magical time traveler keeps going back in time to the protagonist's jump off the tower, each time getting the people to build the pile of pillows a different way in the hope that this new arrangement might save the protagonist. [Answer] If the pillow tower is near the height of the original fall, and people stand at the top of the tower to receive him in a “trust fall” like catch, you can make it happen. Human ladder with a pillow base. [![enter image description here](https://i.stack.imgur.com/XAdSC.jpg)](https://i.stack.imgur.com/XAdSC.jpg) [Answer] Pushing the boundary of the definition of "pillow," I would go with very slippery pillows. There's little need for compressibility because I'm going to arrange them in a catenary or perhaps log curve (I'm too sleepy to apply the calculus to verify maximum vertical delta-vee applied throughout the slide). The fellow's total speed will slowly decrease because the slide is not frictionless, but he'll exit the slide moving horizontally and at worst will suffer abrasions. Wear some thick leather clothes. [Answer] > > He miraculously succeeded in every task, and the exhausted ministers eventually ordered him to just jump down a church tower. > > > This phrasing is ambiguous as to whether it's "they ordered him to jump, such that his jump is from a church tower", or "there was a church tower such that they ordered him to jump from it", i.e. whether the choice was up to him which tower to jump from, or they chose a specific tower. If the former, I'm sure there are church towers from which he could have jumped safely. If the latter, it's quite complicated. It's not like every situation is either perfectly safe or perfectly lethal. There are people who have died from falling one meter, and others who have survived falling from airplanes. A thousand pillows would be in the "survivable, if lucky" range, but I don't think a 100m fall could be made riskless. Another answer assumed 10m of pillow compression, but that invokes further problems. For one, now you have the risk of being smothered under 10m of pillows. For another, just because you have an average* deceleration of 5g doesn't mean you have a maximum of 5g. Almost all of the deceleration would be at the end. To produce an maximum of 5g would require a stack much more than 10m high. If I had to jump off a tower, I would certainly prefer jumping into pillows over jumping onto concrete, but I wouldn't voluntarily do either. ]
[Question] [ Bob is older than he looks. Specifically, even though Bob looks like he's in his twenties or thirties (it's hard to tell), he was actually born in Europe about ten thousand years ago, long before the first word was ever written down. By coincidence (or not), on the night (or the day) of Bob's birth, something unusual happened in the sky. Several people noticed, and thought that it was an important omen. So, Bob grew up knowing that he was born on the day that this particular event happened. Furthermore, with the development of astronomy and computing, Bob has finally been able to determine the exact date that this event occurred, and thus, his date of birth. What could the event have been? --- Answers to questions I've received in the chat room: Does it have to be a one-time thing or is it something that could have happened repeatedly? It can be something that happens repeatedly. A total solar eclipse that happened around that time would fit all my criteria. Just how visible was the event? Visible enough that someone living in Europe ten thousand years ago plausibly could have noticed it and pointed it out to other people. Not necessarily visible enough that multiple people would have noticed it independently. How precisely does Bob need to be able to determine the time that the event occurred? Down to the day. Some astronomical events (like supernovas) can't be calculated back with that amount of precision, so those wouldn't be suitable. Other events (like solar eclipses) can. How much information does Bob already have about the date? I figure that Bob knows the season in which he has born, and he has also calculated the exact number of years since he was born. So he already knows the season and the year; he just wants to pin down the exact day within that season. Are you looking for an actual historical event? Yes, I'm looking for the date that an individual, real astronomical event actually happened. [Answer] Evaluating the various options for astronomical events: * [Solar eclipse](https://en.wikipedia.org/wiki/Solar_eclipse): This is probably your best bet. Total solar eclipses are brief events, lasting only a few minutes. They're also highly predictable, so you could figure out the timing of a past eclipse with sub-second precision. The problem is going to be figuring out which eclipse you saw: since [virtually the entire Earth sees at least one eclipse per millenium](https://en.wikipedia.org/wiki/File:Total_Solar_Eclipse_Paths-_1001-2000.gif), you need to know both roughly when and where a specific eclipse was seen. If there's something unusual about the eclipse (eg. that it was [both preceded and followed by lunar eclipse](https://en.wikipedia.org/wiki/Eclipse_season#Details)), that would help with narrowing it down. * [Lunar eclipse](https://en.wikipedia.org/wiki/Lunar_eclipse): Too many of them. There are between two and five lunar eclipses a year, they're visible from half the Earth, and there's not much to distinguish one from another. * [Supernova](https://en.wikipedia.org/wiki/Supernova): The initial rise in brightness is certainly fast enough to get your desired one-day precision: SN 1006 and SN 185 were both recorded in the Chinese chronicles as stars that were there one day but not the day before. Earth-visible supernovas are rare enough (about one per thousand years) that you'll have no difficulty figuring out which one it was if you've got even a vague idea of when you were born. The problem here is dating: the [Vela remnant](https://en.wikipedia.org/wiki/Vela_Supernova_Remnant), for example, dates from sometime between 11000 and 12300 years ago. * [Comet](https://en.wikipedia.org/wiki/Comet): Doesn't meet any of your criteria. Matching up "great comets" in the historical records to 6300+ known astronomical bodies is highly error-prone, and comets are visible for months at a time. For a comet 10,000 years ago, getting a correct match is hopeless. * [Meteor impact](https://en.wikipedia.org/wiki/Impact_event): This certainly gets the precision you want, with an event lasting just minutes. The problem, like with supernovas, is dating: we can predict future impacts to less than a minute, but past impacts can only be dated through geology, with the attendant lack of precision. * Meteor near-miss: An asteroid grazing the upper atmosphere has the same brief duration as an impact, and leaves the it intact for backwards prediction of its trajectory from modern observations. The problem here is that the small size of an asteroid means it's subject to perturbations of its orbit that can be ignored when back-predicting the movement of a planet or moon. This is something of a long shot, especially compared to a solar eclipse, but it might work. [Answer] Perhaps one of the best astronomical options for you would be a rare planetary conjunction (e.g. two visible planets exactly intersect with each other, or, say all five visible planets come very close to each other, or adopt some specific arrangement, perhaps also involving the moon). Advantages: * Software exists to make these predictions for you (e.g. <http://shallowsky.com/blog/science/astro/predicting-conjunctions.html> ) * Estimates likely have the sort of precision you need (unlike comets, estimates of past planetary orbits are probably precise enough over the 10000 year time frame you need). * They were of note to the ancients, as the motions of the planets against the fixed stars were of great interest: unlike in modern society, it's likely that pretty much everyone would notice a rare arrangement, because pretty much everyone would be looking at the sky each night. Planetary motions were the television series of that era. * Rare conjunctions or other unusual arrangement (like of all five visible planets) have already been used to date things like the start of ancient calendars and have been associated with specific past historical events (like the onset of the black death): <http://adsabs.harvard.edu/full/1994JBAA..104..293D> <https://solarsystem.nasa.gov/news/133/astronomers-solve-ancient-mystery-of-the-chinese-calendar/> * If involving the more rapidly-moving inner planets (and/or the moon), they would provide the sort of duration you need (i.e. an arrangement that peaked on a specific day), rather than some of the other proposed candidate events. e.g. even though the onset of a supernova can be rapid, it is difficult to date accurately in retrospect, while other events (like the appearance of a comet) happen over a time span of months. Another relevant Stack Exchange answer: <https://astronomy.stackexchange.com/questions/11141/how-to-calculate-conjunctions-of-2-planets> [Answer] Solar eclipse is a good idea. They do not happen often, and are visible only from a small area (google "eclipse map"). If he knows approximate location of birth, all he needs is to check a list like one of those: <https://en.wikipedia.org/wiki/Lists_of_solar_eclipses> They do not go back to 10,000 years (that would be 80th century BC, i think), but it is obvious the math is there. You do not really have to pick an actual eclipse, it's not like any of your readers will sit down to do the computations. Another idea is solar+lunar eclipse in same year, or two lunar eclipses in one year. Comets are not a good idea since they arrive so frequently, and there is no way to tell which of many comets it was. [Answer] A volcanic eruption might be a good choice. Widely noticed and can be very accurately dated in the modern era by, for example, layer counting in ice cores from polar ice caps or lake sediments. There are not many volcanoes in northern Europe, but ash from volcanically active Iceland fell in northern Europe at various times. For example, the Vedde Ash originated in Iceland, is very accurately dated to 12,100 years ago, and occurs at a number of sites in Europe. There may be some others from Italian and Greek Island volcanoes in the appropriate time range. In some cases, perhaps in the ice core situation or for example if you have trees near the volcano where you can see the effect of the eruption in the tree rings, you could potentially determine in what season or month the eruption happened. [Answer] We need an event which... 1. happened 10,000 years ago 2. visible from Europe to the naked eye 3. is pretty unique 4. looks the same to all of Europe 5. can somehow be dated down to the day I don't think this is possible. Make that the story. Why does Bob need to know the exact day he was born on some calendar that didn't exist when he was born? Make the story about Bob's journey from obsessing about his place in history, to coming to accept it's going to always be a little ambiguous. Maybe Bob has counted solar eclipses since he's been born. He gets very excited about the new science of astronomy in the Renaissance, finally they answer his question! The Renaissance astronomer shows him the fascinating new models of the Solar System and how he can predict eclipses forward and backward. Yes, they give Bob a date, but note it's an approximation. Disappointed, Bob continues his search for his birthday. Maybe he learns a ton of math, astrophysics, and archeology in the process. Fast forward to modern times. Bob is excited about super computers and the ever increasingly accurate models of the Solar System. He talks to a modern astronomer who says yeah, they can calculate Bob's eclipse down to the minute! But Bob gets the same speech; don't be seduced by the precision of the computer model. It's still an approximation. While the answer might seem precise there's still error bars of days. They can't give Bob any assurance this is very precise looking calculation is really Bob's birthday. Bob, frustrated and angry after searching for centuries, lets loose on the astronomer. What good are all these computers and all this precision all this math and science if they know every answer is wrong?! He tells Bob all the imprecision and approximations in his eclipse counts. He has to trust that Bob remembered all of them correctly. That it was never cloudy on an eclipse day. And that what's a full eclipse in one part of Europe might be a partial in another. Even if Bob's observations were correct, the astronomer explains chaos theory as it applies to astrophysics. No matter how powerful the computer there will also be some details they're leaving out of the model, details that could effect the timing of Bob's eclipse. Bob finally realizes that science isn't about the search for certainty. Religion provides certainty, but it does so by over-simplifying and detaching itself from messy reality. Science accepts reality for what it is, and they need to figure it out through a million imprecise observations. A good scientist accepts their answers are inaccurate while continuing to chip away at those inaccuracies. A good scientist knows the math is a model of reality, not reality itself. A good scientist knows their job isn't to find The Truth, but to produce answers which are good enough to get the job done. The modern astronomer says the calculations are done, "would you like to know when the computer says you were born?" "No", says Bob, "I already know it well enough." Bob digs out a scrap of parchment from his notes and shows it to the astronomer. It's the date the Renaissance astronomer gave him centuries ago. "You're invited to my birthday party." [Answer] Maybe it could be ash from a volcano causing the full moon to appear ominously red. If Bob already knows the year and season, knowing it was a full moon will be enough to pin down the exact day. A possible candidate volcano would be the Grímsvötn eruption in Iceland, 8230 BC. [Answer] [Sodom and Gomorrah](https://en.m.wikipedia.org/wiki/Sodom_and_Gomorrah) are good candidates. No proposed explanation was accepted so volcanic activity is unlikely. Maybe a meteor shower? A much more recent one (out of your time scale but may have happened earlier many times) is the famous [SN\_1054](https://en.m.wikipedia.org/wiki/SN_1054). (Abbreviation of Super Nova of the year 1054), in the crab nebula, observed by Chinese astronomers the same year. [Here](https://en.m.wikipedia.org/wiki/History_of_supernova_observation) are more ancient records. [Answer] The [saros](https://en.wikipedia.org/wiki/Saros_%28astronomy%29) is a period of 18 years, 11 days, 8 hours (or 6585.3211 days), and represents the amount of time after some given eclipse when an identical eclipse will happen again. As with any estimate it's not completely accurate, but we can and have estimated many [lunar](https://en.wikipedia.org/wiki/List_of_Saros_series_for_lunar_eclipses) and [solar eclipses](https://en.wikipedia.org/wiki/Solar_Saros_136) to the day. As for Bob's birthday, 555 saros periods would represent about 10,006.441 years. Legends state that he was born on a total lunar eclipse when the moon was descending, so if he starts from the date that type of eclipse last happened and puts in the effort to take into account leap days he could make a pretty good guess as to when he was born. --- 1Just a rough estimate, (6585.3211 \* 555) / 365.25 = 10006.4427392 years [Answer] [Hale–Bopp](https://en.wikipedia.org/wiki/Comet_Hale%E2%80%93Bopp) ([images](https://www.google.com/search?q=comet%20hale%20bopp&rlz=1C1NHXL_enGB711GB711&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj9ruvi2LPfAhXBShUIHX-bBFgQ_AUIDigB&biw=1280&bih=617)) last seen 1997 when it was visible for 18 months (the last time it came around before that was about 4200 years ago), it was very visible & a very impressive sight for a long time & would certainly have been noticed each time it's visited in the past. > > I had a short cruise around Google to try & find other previous dates it visited to try & find you the one closest to your 10,000 year mark but not a lot of joy on that so far. > > > By far the most impressive space related event I've witnessed myself & hung around long enough it couldn't possibly be missed so I'm convinced this would be an excellent choice for what you want. You want a single day so how about the first day it would have been visible to the naked eye, Bob is born on a night when a new small pin prick of light is visible in the night sky (it's noted but no one really thinks that much about it), it grows over the following weeks & months into a really impressive sight, everyone decides Bob must be special, then it slowly fades & disappears from the night sky. Of course maybe it wasn't the first day it was visible to the naked eye, maybe it was just the first day anyone in his tribe noticed this new object growing in the night sky. Which means Bob will never know for sure the exact day he was born. Is it absolutely integral to your plot that Bob has to be able to pin down exactly the day of his birth in the modern calendar? because I don't think that's going to be possible with any astronomical event. Of course you could fix this with some additional information, he was born on the Summer (longest day) or Winter (shortest day) Solstice of a year the comet visited & it's been back twice since then. That ^ would give you an exact date. > > It doesn't have to be on the exact day of either Solstice either, simply knowing an exact number of days before or after either Solstice or Equinox that he was born along with a notable astronomical event to identify the year with will give you an exact date. > > > [Answer] I'm gonna go with [Halley's comet](https://en.wikipedia.org/wiki/Halley%27s_Comet). It's visible from the Earth, might have been recorded as 467 BC. So it has probably been cycling for longer. It has a cycle of 75.32 years, and was last seen in 1986. So, if I can still do some basic maths, it passed by 9974 years ago. It can be seen with the naked eyes from the Earth, can be easily noticed and can be well dated. [Answer] Perhaps a [Meteor Air Burst](https://en.wikipedia.org/wiki/List_of_meteor_air_bursts). Though they're anything but regular normally, they can only be observed from certain areas and you could arrange for their regularity. Though its exact cause is still up for debate, the [Tunguska Event](https://en.wikipedia.org/wiki/Tunguska_event) was highly-noticeable and is perhaps the most famous example. Physically-destructive events often leave a great deal of evidence. Perhaps a town or simply a building was destroyed, buried, and since uncovered with some easily-dated items inside * propaganda from or art depicting a ruler * precision tools or weapons showing the metallurgical science of the day This could show up as exciting science news, reaching Bob via modern means, but not (yet!) have been discovered today. ]
[Question] [ In [Creating a realistic world map - Waterways](https://worldbuilding.stackexchange.com/q/21402/627), I asked about exactly what processes affect how rivers flow and meander. With some of that knowledge in mind, I'm curious as to how a worldbuilder (like myself, for instance!) could go about creating a river on a map, especially in flat regions. As was the case [with coastlines](https://worldbuilding.stackexchange.com/q/21349/627), which I think I've gotten better at, my current method is to draw little squiggly curves based on any existing topology I've figured out. But that's still annoying. Is there a better way that is commonly to simulate this? Some things I'm looking for: * Computational efficiency * No extremely unrealistic features (i.e. a river constantly doubling back and intersecting itself) * Some semblance of control over the final product I did go into detail about the fractal algorithm in my answer below. Answers don't have to go into that much detail, or even show a finished product. A simple description of the algorithm is fine. [Answer] I can't help you much with coding but I can help with what to look for to tell if you have gotten it right. Just elevation will take care of a lot, once you know where the basins are you know the direction and size of your river systems. That does mean you need to plot your mountains before the rivers. lets look at a map of river basins in the US. [![](https://i.stack.imgur.com/mTber.jpg)](https://i.stack.imgur.com/mTber.jpg) now compare it to mountain range placement. [![](https://i.stack.imgur.com/Xvf15.png)](https://i.stack.imgur.com/Xvf15.png) notice that outer edge of each basin is defined by either a coastline where the river dumps into the ocean or it is mountains/high lands. Notice that as you get further into the land mass the number of basins drops dramatically while along the coast there are many many small basins (and thus small rivers). You can do a rough plot of a river system by just plotting how to get from from any point to the coast without crossing higher elevation. Water follows the path of least resistance and generally from mountains to ocean. Then you need to add some randomizing effects to account for the local variation you are not modeling. Someone else will have to help you on how to add such more or less variation. in addition how much a river wanders back and forth is a function of the slope of river, steeper fast moving water cuts a more direct line (although never straight) while shallow sloped (and thus slow moving) water meanders, if the land is flat enough this wandering can become very extreme. [![](https://i.stack.imgur.com/prjg0.png)](https://i.stack.imgur.com/prjg0.png). Completely isolated land-locked basins are rare, only occurring when a a complete ring of mountains exists. These feed in to isolated lakes that become hyper saline(salty). Utah's salt lake is a great example. Normal lakes are created by local lows that fill up and overflow creating an outlet. The vast majority of lakes will have an outlet, that is an exiting river. Not large rivers often produce deltas when they reach the sea, they are so flat so slow moving they dump sediment blocking themselves creating a branching pattern. these end up looking like fans or dense trees pushing out into the ocean. [![](https://i.stack.imgur.com/GNj2M.jpg)](https://i.stack.imgur.com/GNj2M.jpg) [Answer] I'm self-answering my question, but please don't let that deter any other answers! I'm definitely curious to see if there are any other common techniques. # Use [fractals](https://en.wikipedia.org/wiki/Fractal)! In the previous question about coastlines, [Samuel's answer](https://worldbuilding.stackexchange.com/a/21357/627) pointed out that [fractal landscape](https://en.wikipedia.org/wiki/Fractal_landscape) techniques can work very well for simulating coastlines. The degree of self-similarity is often startling. I've implemented an algorithm to do that, and it's produced very good results. It also turns out that rivers, too, exhibit fractal-like patterns, and over areas that are relatively flat, they can be simulated - by fractals! Fractal river modeling is actually a very effective technique, and is often used. The first step to generate such a river is to determine the terrain. If you want, you can use fractal techniques using the [diamond-square algorithm](https://en.wikipedia.org/wiki/Diamond-square_algorithm), for instance. You can also figure it out via various other methods; I've used random methods that begin with a circular region, then randomly increase the decrease the elevation while moving inwards - weighted, of course, with a tendency to go upward, rather than downward. After that, you could add even more detail by modeling erosion patterns using, for instance, [cellular automata](https://en.wikipedia.org/wiki/Cellular_automaton); Jasper McChesney wrote [an awesome post on the Worldbuilding blog](https://medium.com/universe-factory/this-post-is-about-a-world-building-tool-ive-been-working-on-5d9560844ff5#.1au1ozeuj) about this. Even without using Jasper's algorithm, I've already found some results I like. Here are some examples (these are shown as contour maps; green, yellow, orange, and red are above sea level): [![enter image description here](https://i.stack.imgur.com/u9jhv.png)](https://i.stack.imgur.com/u9jhv.png) [![enter image description here](https://i.stack.imgur.com/8sFbR.png)](https://i.stack.imgur.com/8sFbR.png) I bring these up in particular because they have interesting features: Valleys and sharp downward gradients, as well as sections of flat land going down to the sea. The valleys mean that I can figure out where a river might go. In places where there is a clear downhill path, it's simple to figure out a river's path. However, some of the valleys are still wide, and they all eventually end, leading to flat areas with no clear path for the rivers to take. How, then, can I simulate where the rivers will go? One answer, of course, is fractals. Here's a version of the (commonly used) method I've been using for coastlines, adapted and modified for rivers: 1. Pick two points, the places where you want this portion of the river to start and end. Call them $p\_1(x\_1,y\_b)$ and $p\_2(x\_2,y\_b)$, and put them in the set of points, $P$. I give them the same $y$-values, for simplicity's sake; you can rotate the map any angle you choose, and we might as well keep things horizontal. Let's also set $y\_b=0$. 2. Draw a line segment between the two points. Divide it into $N$ subintervals, each of length $$l=\frac{\|x\_2-x\_1\|}{N}$$ 3. At the center of each interval, pick a random length $d$ between $-\frac{l}{a}\frac{1}{j+1}$ and $\frac{l}{a}\frac{1}{j+1}$, where $a$ is some constant and $j$ is the iteration number. We begin with $j=0$ when running this for the first time. 4. Add another point, with the $x$-coordinate at the center of the interval and the $y$-coordinate being $d$. 5. Add all of the new points to $P$, reordering $P$ in terms of how they are connected to each other. 6. Repeat steps 3-5 as many times as desired. 7. If you want, you can then using some sort of spline to make a nice, smooth curve encompassing all of the points. You now have a segment of a river! Simply insert it onto your map between the desired points, and see how the world evolves. Do this for as many segments and rivers as you desire, although be careful to do this mainly in flat regions, where the topography won't have a major impact. The bests results I've gotten are actually for $N=1$ and $a=10$, over four iterations. There are, of course, some duds - cases where the river crosses over itself, for instance - but there are also some gems where you get proper, repeated meanders, like a real river: [![enter image description here](https://i.stack.imgur.com/diB3f.png)](https://i.stack.imgur.com/diB3f.png) [![enter image description here](https://i.stack.imgur.com/e7crs.png)](https://i.stack.imgur.com/e7crs.png) (The code used to create these is now on [GitHub](https://github.com/HDE226868/Fractal-landscapes/blob/master/Rivers.py).) Note that the vertical scale is expanded for effect. The swings aren't really as wild as they appear; they're actually much smaller, and the river doesn't deviate drastically from a straight line - just enough to get some realistic meandering. I know what some people are thinking right now. "But HDE, couldn't you just use a random walk?" Well, yes, you could use a [Gaussian random walk method](https://en.wikipedia.org/wiki/Random_walk#Gaussian_random_walk). That's rather simple, and might actually be computationally simpler. To make it realistic, all you'd have to do is vary the step size randomly. There are, however, a couple issues I have with using a random walk in this case: * There's no guarantee you'll reach your desired endpoint, which is a problem. I suppose you could start random walks from both endpoints simultaneously, and see where they match, but that could take quite some time. They might never meet. * It's not very hard for the walk to cross back over itself. If you implement the fractal midpoint algorithm, it's true that you'll have some cases where the river crosses itself, and that can be a little annoying. However, most runs will not have this kind of issue. The same can't be said for the random walk method. This is why fractals are much better suited for river modeling, coastline creation, and terrain generation than random walks are. You have more control, while still ensuring that there's plenty of healthy variation over the course of the river. Here's another thought. Perhaps you don't want your river to run perfectly straight. You've generated your terrain already and have determined a general path for the river to follow, in accordance with the elevation. At this point, it might seem that the fractal method is pointless. It isn't. All you have to do is adapt the algorithm to a straight line, replacing $l$ with the arc length along the curve from point $p\_i$ to $p\_{i+1}$, and the slope of the line perpendicular (and passing through) the midpoint of each (now curved) segment with a line normal to the curve (i.e. perpendicular) at that point. The rest is simple; in fact, after each step, you can redo the spline, creating a new curve each time, with more detail. Alternatively, you can wait until the end and do something similar to what we did before, in effect, just using the initial path as the basis for the first iteration only. I haven't tried any of this myself, but it's a promising method. There are a couple things to take into account here: * You'll need a parametric description of the initial curve, i.e. writing the curve $C(t)=(x(t),y(t))$ as a function of $t$. * You'll also need to know certain values through which the curve goes. * You'll have to calculate arc length if you want to figure out the exact midpoint of each segment. That shouldn't be too challenging numerically. You could - if you really want - eyeball these steps, but I'd prefer to compute them. Here's a case of what I'm talking about, with all parameters and curves estimated by hand (well, by Paint). The river to the west is just a modified straight line, with one iteration of the original algorithm. The river to the east uses an initially curved path dictated by the terrain, with a secondary bend: [![enter image description here](https://i.stack.imgur.com/5zJhj.png)](https://i.stack.imgur.com/5zJhj.png) I should add one final note, because some people reading this may be confused by now. Fractals and self-similarity are also often applied to rivers, but in terms of the generation of tributaries, i.e. how a river branches off. These are two different things, and absolutely should not be confused. I apologized if I have anyone puzzled by this; the coincidence is not ideal. [Answer] For the coding side you could just use [Perlin Noise](https://github.com/HDE226868/Fractal-landscapes/blob/master/Rivers.py). Just search it up if you don't know what it is. It also offers nearly full control over your final product. [![enter image description here](https://i.stack.imgur.com/Te8w6.jpg)](https://i.stack.imgur.com/Te8w6.jpg) [Answer] Okay, I'm not into the code side, but I did work on several roadway/bikeway projects that included coordination with hydraulic analyses. These were on a local level, however, so I'm going to try to ramp it up for your world. From your contoured map, since we don't know your soil situation (don't need to, if we're just doing a snapshot). Information you want to know ("input"? I know nothing about computer modeling) These are the variables that our water guys would use in their models and if you know more about computing than I do - I already know you do HDE - then maybe they're the considerations you want to use, too. * Flow Distribution - there are apparently [algorithms](http://www.exothermia.com/home/index.php?option=com_content&view=article&id=53&Itemid=82&lang=en) for modeling this, but how I would do it by hand or by a lesser involved practice is using your depth (below) and width you can have the spread out. [![enter image description here](https://i.stack.imgur.com/Igxdc.jpg)](https://i.stack.imgur.com/Igxdc.jpg) * Velocity Distribution - see above. This is affected as well by volume and cartography. If you know a way to combine the two types of distribution, you begin to see a two-dimensional map of a river. * Water Surface Elevation! - most important, as water flows downhill. This will affect distribution. * Velocity magnitude - should be self explanatory. * Velocity direction - should be self explanatory. * Flow depth - Depth is important when calculating how much volume you can get at once. You can use a polynomial to get a cross-section of your desired river, and then multiply that along the river: somehow a computer can do that quickly for a complex river. [![enter image description here](https://i.stack.imgur.com/E0nOp.png)](https://i.stack.imgur.com/E0nOp.png) * Shear stress - These were for bridges, so I don't think you need to model that to make a map, unless you're getting really intense on the land features your rivers come up against; for example if you have igneous rock that is very tough, more likely a river is diverted around it or over it like a waterfall; this is found in areas that had tectonic activity. So you have your contour map, now do your computer magic with the first input being volume. Rainwater on the mountains, artesian wells from aquifers, and don't forget human wastewater (that's actually significant) will get it started in the headwaters, and then the variables above, modeled from your contour map, will define generically the route the rivers take. This is just a snapshot in time as @shufflepants noted. Your rivers conclude in a delta in flat, sedimentary areas or a gorge straight into the ocean in areas that have steep, deep, rivers. River types are explained in depth in the accepted answer to your [Realistic World Map - Waterways question](https://worldbuilding.stackexchange.com/questions/21402/creating-a-realistic-world-map-waterways). [![enter image description here](https://i.stack.imgur.com/wglYK.jpg)](https://i.stack.imgur.com/wglYK.jpg) This leaves me at the end of what little experience and knowledge I have. The next step is the hard part. [Answer] there was an article written about 40 or 45 years ago in the Scientific American about sin generated curves. it is the process that rivers, train wrecks and blood vessels use to collapse while spreading the energy evenly over the process. this is why river meander can look like blood vessels. I just found the article is was referring to: ers. Scientific American, 214, 60-70. <http://dx.doi.org/10.1038/scientificamerican0666-60> I think it is on point for you. there are other good papers on the subject of sin-generated curves as well. [Answer] What i tend to do when practicing my fantasy map making skills, is to draw out layers of elevation, and then use a filter to give the impression that the land isn't flat, before drawing the river using the path of least resistance from it's origin towards the sea. Snippet from one of my maps: [![Map snippit](https://i.stack.imgur.com/dIdNk.jpg)](https://i.stack.imgur.com/dIdNk.jpg) Not sure if you can see the differences in elevation, as the colour makes it a bit difficult to tell, but i hope you get the gist of it. [Answer] To expand on what John said (I love the river map BTW), very little is actually flat. Any plain that does not end up being a lake has a slope and the water travels through that plain to the lowest point. The plain generally has high and low spots (from less than a meter to 10s of meters) and the rivers tend to follow those. So, the slope and the terrain and the "bumpiness" will determine the shape of the river. If the terrain is flat and the slope is low, you tend to get "squigglier" rivers. In the first photo in John's post, the force of the water overcomes the terrain features. Since the water on the outer side of a curve travels faster than the water on the inner side, the river erodes the outer bank faster than the inner bank. That causes the loops to extend outward over time. Then they can get pinched off by the water finding a more direct path and you end up with those "arc lakes" around the river. If you are writing an algorithm, I'd have the brownian motion biased by the slope and the bumpiness of the terrain. If the water ends up somewhere without an outlet, make a lake and raise the water level to the lowest outlet and begin a new river. Using this method, the water will eventually get to sea level. However, if you factor in evaporation, the water may never reach the sea in dry areas. [Answer] A fitting response for Pi Day. As a river flows it meanders through the landscape, it traces a curved path. If you take length of the river, and divide it by the direct route from the start to the end of the river, you will get the "sinuosity" of the river. This is a measure of how bent the river is. Any given river can have a range of sinuosities, however you can demonstrate that the average sinuosity of all rivers in the world should be... Pi. Seriously. [Watch this awesome video from Numberphile to learn more](https://www.youtube.com/watch?v=TUErNWBOkUM). It is a curious fact that is the result of how rivers form oxbow lakes, straightening themselves in the process. In practice, you don't find sinuosities greater than 3.5, and not really below 2.7. Remember that pi is the expected average of all rivers, and this is under ideal conditions. Real world topography will cause this to vary, but this serves as a good approximation as to how straight or bent a given river should be. [Answer] IMHO, neither of your graphs appear to be plausible rivers. For one (obvious) thing, their length is minuscule. Sea level is an arbitrary artifact of global temperature and available surface water. Continents, on the other hand are the result (on this planet, at least) of the creation, collision, and subduction of tectonic plates. A river system is what drains an aquifer. If an area were created flat, then there'd be little reason to expect one river to form. The river system would most likely be formed highly branched at all levels of length. As a recreational biker, I can tell you that there are few areas on Earth which are "flat" (salt flats being the exception). The problem with your assumption of flatness, is that there isn't going to be any drainage, which means no reason for a river to exist. So, the way I would create a world would be: * Start with the topography. * Next pick a sea level. You should be left with some islands and some bigger chunks. * Once you have that, figure out rainfall - wind and mountains, as well as large, dense forests have great influence there. * Once you've got rainfall, you need a drainage system (known as a river) which will take roughly one unit of water (temperature, wind of course impact that) to the sea. Feel free to (randomly) vary the unit by a factor of 2 or so. * So, now that you have an area to drain, you know for sure that the drainage has to start at the highest point (I'd exclude mountain peaks, say above the timberline) and end at one or more of the lowest points. You're either going to get a lake, or flow into an adjacent area. The difference between this approach and yours is pretty profound, imho. You want to connect two points. I say, drain the whole country, starting with the highlands, working towards the lowlands. Not from point 1 to 2, 3 to 4. But from areas A,B,C,... to points α,ß,Γ,... simultaneously working your way down in elevation. By the way, you should include both meanders, braids, and anastomoses (see <https://en.wikipedia.org/wiki/Channel_types>) - at least in some cases. [Answer] First of all, go to YouTube and search why do rivers curve, and click on the fist one. I found this video very helpful. Most of what I can tell you is from that video, so here are some key points: The length of one "s" in a river is roughly six times the width of the river. If any disturbances are in the way, the river will simply go around the disturbance. A meander can be caused by nearly anything, so they ate quite common. Sometimes the s will be thinner than others because it has formed an oxbow lake. [Answer] Looks like your diagram has least one example of river capture (river flows into the sea down one route and into a lake via another on the same river) which is not that common and at the point of capture where water can flow down both branches the situation will be very short lived (“H” shaped). Most rivers flow into the sea eventually although in some cases in hot areas evaporation can lead to evaporative basins. You have a number of these with lakes which is ok, but be mindful of the unusual circumstances around this. If you want to generate a realistic river then I suggest you should start at the top head water or the outflow and work from there downstream or upstream. If working upstream there are a number of questions you should think about, firstly how much water is flowing out? All other things being equal that will help determine the area of the river basin and the length of the river. You can then work upstream with branching tributaries as you go along. Each mile of river and each tributary should decrease the size of the river. Obviously (calculating the river his way) the flow is uphill so as time goes on there should be an increased likelihood of hills or mountains. So the river will define where the high ground is. The other way to do it is to work downstream if you’re starting inland. In this case there must be an assumption of lower land ahead as well as the chance of merging tributaries. In this case the rivers wil define where the sea is. In very large rivers at low elevations near the sea there is also the possibility of distributaries forming and the river fanning out into a delta. I would avoid the “H” shaped sections of river except perhaps in a delta region. I would think carefully about having rivers following into landlocked lakes as well. It’s possible and there are many examples but it’s far less common than rivers flowing into the sea by several orders of magnitude. You may want to consider using a different algorithm for the different stages in a rivers development from fast mountain streams to slower lowland rivers with more and more loops and flood plain topology (ox bow lakes) finally and optionally a delta. Incidentally a river in a flat area may well loop in such a way that it cuts off part of itself. This is what oxbow lakes are. <https://en.wikipedia.org/wiki/Oxbow_lake> ]
[Question] [ I am a [Traveller (game)](https://en.wikipedia.org/wiki/Traveller_(role-playing_game)) referee. I've generated lots of worlds before, using a basic system that describes a world in eight fundamental pieces of data. For the record, those data are: > > Starport class, from "none" to first-rate, primarily and specifically to note the world's willingness to trade. > > > World Size, from asteroid up to super-Jovian. > > > World Atmosphere, which includes pressure, human breathable-ity, and the presence of corrosives, plus some edge cases. > > > World Hydrographics, a percentage. Doesn't necessarily mean water (that depends on the atmospheric code). > > > World Population, as an exponent of ten. > > > World Government, from "no government" up to severe police state. > > > World Law Level, basically how annoying the authorities are to you. > > > Tech Level, from neolithic to fantastic-future tech. > > > But many times, similar world types keep showing up. Water worlds, or vacuum worlds, or worlds with an industrial taint. This is a feature, not a bug, and yet I wonder if just a little bit of simplification can remove a lot of data. Consider Star Trek's "Class M Planet". One letter is doing a lot of work: it describes general size and life, as well as a breathable atmosphere. A very compact notation indeed! So. Is there a list of 26 (or so) single-letter basic "planet types" that's useful for describing worlds? I'm looking for something that holds data useful to casual readers or gamers, so I guess I'm thinking about it in the "Star Trek" fashion, but maybe there's an angle I haven't thought of. To be more explicit, when we get together to play Traveller, we're interested in things like whether this world is a miserable asteroid, or something larger, up to super-earth sized perhaps (i.e. can I walk on this world?); is there air, if the air is breathable (or, perhaps, how long it takes before suffering ill effects), whether there's accessible water, how much of the world is wilderness (or, perhaps, how many people live there), if there's a world government, if the locals are primitive or tech-savvy, and so on. Update FYI, Wikipedia lists Star Trek's codes, which generally seem to fall into these buckets: ``` A,B,C: Small, uninhabitable worlds. D: Large planetoids. E,F,G: Earth-sized but less habitable. Perhaps younger. H: Desert worlds. T,S,I,J: Gas giants, largest to smallest I guess. K: Earth-sized but uninhabitable. L: Earth-sized with a marginally breathable atmosphere. M: Terran norm. N,X,Y,Z: Hell-worlds. Insidious or corrosive atmospheres, high temps. O: Water world. P: Tundric water world. Q: Elliptical atmosphere or other strangeness. R: Rogue world (a wanderer; it does not orbit a star). ``` I like certain elements of the list: habitability is there, as well as sensory tropes such as water worlds and desert worlds; there's room for oddballs such as the Rogue world; and planet size is treated well enough. The Planetary Classification List This website (<https://orionsarm.com/eg-article/491c78b89879b>) lists planet types by name... and has a bunch; it could be whittled back. Rob's Musings Let's say orbital location is separate, thereby subsuming molten and ice and rogue worlds. Add in a couple types to describe technic societies and we may have something... but it's hard to combine environment + technology into less than 5 bits! Lossy! ``` A Metal-poor (no atmosphere) (Luna) B Metal (Iron)-rich (Mercury) (no life) C Greenhouse world (Venus) (no life) D Carbon world (CO or methane, tar lakes; primitive life at best) E-K Unassigned L Sulfuric world M Meso Sulfuric world N Technic Sulfuric world O Ammonia world P Meso ammonia world Q Technic ammonia world R Chlorine world S Meso Chlorine world T Technic Chlorine world U Smallworld (Mars) (NOTE: includes "early" Mars!) V Meso smallworld W Technic smallworld X Gaian (primitive life) (NOTE: includes waterworlds and desert worlds!) Y Meso Gaian Z Technic Gaian NOTE: Meso: sophonts without space travel NOTE: Technic: sophonts with space travel ``` ALTERNATELY, the code could focus on things other than sophont status. @Mathaddict noted: "The classification should really be differentiated into what equipment they will need in order to land/survive/etc." That's a good angle, with things such as breathing-protection, skin-protection, eye-protection, and mobility. [Answer] Of course we can make this code up. The question is, how useful it would be. As @Renan pointed out, possible permutations of planet types number in thousands - and that's not even counting potential life and civilization on the planet. Coming up with single code for every type is impossible. But if we want just a classification, then yes, we can come up with 26 types that would group together similar planets. The only challenge is to make these groups practical. I would suggest to use frequency of mention to guide this classification. This way, if two very similar world types (like "clean" and "tainted" Earth-like planets with civilization) are mentioned very frequently, they deserve their own letters. On the other hand, planetoids without atmosphere could be much more numerous and diverse, but because they mentioned less frequently, they may be all compressed into one letter designation. This one-letter code would not eliminate the need for proper, multi-symbol classification that should reflect all major aspects of planetary conditions. [Answer] As far as I know, that kind of list is only found in Star Trek EU works, specifically the Star Charts, which shows a planetary classification from Class A to Class Y with some useful information. [![Star Trek: Star Charts - Planetary Classification](https://i.stack.imgur.com/nxY2u.jpg)](https://i.stack.imgur.com/nxY2u.jpg) [Answer] It might be too coarse for you needs (as in "not detailed enough"), but you could use the [Universal Planetary Profile](http://wiki.travellerrpg.com/Universal_World_Profile) from the RPG [Traveller](https://en.wikipedia.org/wiki/Traveller_(role-playing_game)). (In the modern version of the game, it's called the Universal World Profile and is far more comprehensive than in the original game that I'm most familiar with.) The format describes: ``` Starport (Sp) Planetary Size (S) Atmosphere (A) Hydrosphere {H) Population (P) Government (G) Law Level (L) Tech Level (TL) ``` [Answer] I'd personally as a reader want to be able to differentiate between planets easier than that, and an easier way to do that might be to use a [taxonomic system](https://en.wikipedia.org/wiki/Taxonomy_(biology)) for classification. Instead of having so much variation like animals, you can have a class A-B-C planet meaning different items, with further breakdowns in classification beneath that. Just like using the word "plant" versus "flower", we can use these indicators to provide ever increasing levels of specificity. It doesn't need to be anything completely complicated, but provide the full 5 bits, putting emphasis on certain pieces over others based on how important someone would use them in conversation. > > First letter determines size and type. > > > * A: Gas planet, strong gravitational pull, tidally locked > * B: Gas planet, normal gravitational pull, tidally locked > * C: Gas planet, weak gravitational pull, tidally locked > * D: Gas planet, strong gravitational pull, tidally unlocked > * E: Gas planet, normal gravitational pull, tidally unlocked > * F: Gas planet, weak gravitational pull, tidally unlocked > * G: Rocky planet, strong gravitational pull, tidally locked > * H: Rocky planet, normal gravitational pull, tidally locked > * I: Rocky planet, weak gravitational pull, tidally locked > * J: Rocky planet, strong gravitational pull, tidally unlocked > * K: Rocky planet, normal gravitational pull, tidally unlocked > * L: Rocky planet, weak gravitational pull, tidally unlocked > * etc. > > > Then further elaborate into atmosphere type and hostility of location. > > * A: Weak atmosphere, close to star, hot > * B: Weak atmosphere, close to star, temperate > * C: Weak atmosphere, close to star, cold > * D: Normal atmosphere, close to star, hot > * E: Normal atmosphere, close to star, temperate > * F: Normal atmosphere, close to star, cold > * G: Strong atmosphere, close to star, hot > * H: Strong atmosphere, close to star, temperate > * I: Strong atmosphere, close to star, cold > * J: Weak atmosphere, Goldilock's Zone, hot > * etc. > > > After that, you can get into habitability, resource availability, breathing possibility, and population with just numbers. > > * 01: Not habitable, scant resources, breathing apparatus necessary, not populated > * 02: Habitable, scant resources, breathing apparatus necessary, not populated > * 03: Not habitable, normal resources, breathing apparatus necessary, not populated > * 04: Habitable, normal resources, breathing apparatus necessary, not populated > * 05: Not habitable, heavy resources, breathing apparatus necessary, not populated > * 06: Habitable, heavy resources, breathing apparatus necessary, not populated > * 07: Not habitable, scant resources, breathing apparatus not necessary, not populated > * 08: Habitable, scant resources, breathing apparatus not necessary, not populated > * etc. > > > Forming from this, you could classify any type of planet, and instantly know what sort of place you're visiting. For instance, Earth might be classified as a K class planet, but with further information on it bearing more fruit. > > Earth: K-P17 planet > > Population: 7.2b > > Crust Compostion1: > > - oxygen, 46.6% > > - silicon, 27.7% > > - aluminum, 8.1% > > - iron, 5.0% > > - calcium, 3.6% > > - sodium, 2.8% > > - potassium, 2.6% > > - magnesium, 2.1% > > Intelligent Species Types: Humans, Dolphins, Mice > > Prevalent Languages: > > - Mandarin Chinese (1.1 billion speakers) > > - English (983 million speakers) > > - Hindustani (544 million speakers) > > > > With this, you have a complete knowledge of a planet, and can further fill in more information on a longer format, but can refer to Earth as a K class planet, then further specify with more taxonomic indicators. 1 - "Essentials of Geology" (7th Ed., Prentice Hall, 2000) by Frederick K. Lutgens and Edward J. Tarbuck [Answer] ## Weighted k-medoids clustering [k-medoids clustering](https://en.wikipedia.org/wiki/K-medoids) is a method of dividing a set of points into clusters of similar points. You can use this to divide your worlds into clusters, and then give each cluster a label. One algorithm to do this is the PAM algorithm: 1. Give each world a weight (representing how likely it is to come up in conversation). Also define a "dissimilarity" function that measures how dissimilar two worlds are. This should make the set of worlds a metric space. 2. Give each label a "metroid" world. This can either be done arbitrarily, or meaningfully (the meaning of the labels will be loosely based on these initial metroid worlds). The metroid world does not need to have a high weight; it could even have weight $0$. 3. Assign each world the label whose metroid is most similar to it. 4. Calculate the weighted average cost of the labelling, which is defined as the weighted average dissimilarity between a world and the world's label's metroid. 5. For each label $l$ and each non-metroid world $w$, change $l$'s metroid to $w$. Then do steps 3 and 4 again. If the weighted average cost went up, undo the change. 6. Keep doing step 5 until the weighted average cost stops decreasing. 7. The current labelling is the output of this algorithm. You may want to rename the labels if you want them to have meaningful names, as the algorithm will probably have relabelled worlds multiple times until it found a local minima. [Answer] I don't think there is a good way to simply classify planets with the granularity you want without creating a barrier between you the creator and the audience you are presenting to. For your system to work, the user needs to know and remember it. This is hard. You can't just present it in a table (I'm assuming your users are both gamers and readers) in the appendix or index because a user needs to keep flipping back to it. This breaks the flow of your story or game (sort of like tutorial prompts) and creates a disconnect for casual or first time users who might not want to invest in learning everything and just dive straight in (this is one of the reasons why casual and mobile games are such a huge market compared to knowledge intensive RTS games). A very basic system would be something along the lines of: * Planet/Asteroid/Star * Livable/Unlivable Which can give you the following combinations: * Livable Planet * Livable Asteroid * Livable Star Which you could then sort into a code that you want e.g. (LP, LA, LS). But a casual user doesn't understand this, especially if you want to factor in all possible factors of a planet. The only thing you are doing with such a code is making it harder for a user to understand your game. If you really want to... Unicode has 137,374 mappings which means you could, if you really really wanted to, present 137,374 unique combinations to the reader with a single character (some of them look exactly the same, but they are different). But at that point you might as well be using Webdings. [Answer] Check [the wiki for planet types](https://en.wikipedia.org/wiki/List_of_planet_types). There are eight types by size, seventeen by orbital regime, seventeen by composition and three miscellaneous types. That does for 6936 possible combinations, so if you wish for one letter descriptors you may need to use chinese characters. Otherwise, you can use any fictional classifications such as Star Trek's, as long as you don't do it commercially I guess. [Answer] Can you use something like vignettes? A vignette is basically a short description of something with a catchy name. Define a list of the most useful planet types and create a small vignette for each. For example: # Industrial World Habitable world with a well developed, space faring infrastructure. bla bla bla # Planetoid Lifeless world with little athmosphere. The trick is to write these in a way which allows for modification - e.g. add a "heavy" before industrial world and you get a slightly different meaning. This list has to be shared with your group, so when they hear "industrial world" they know what to expect and what to ask to further define the planet. [Answer] These seemed like an interesting challenge, and while some simplicity is possible, you cannot fold in the complexity and intelligence of life into it without making it overly complex. The detailed way of identifying a planet or moon needs too many values: * mass and surface gravity, surface composition * biosphere (mass, area, complexity, intelligence) * atmosphere (thickness, composition, surface pressure) * temperature (surface mean, range) * orbital dynamics (zone, eccentricity, length of year) * rotational dynamics (length of day, axial tilt) * solar dynamics (mass, sequence, brightness, spectral class, wind output, stability, ttl) * geomagnetism, geological stability, and more... This is just too much data. But what if we limited our criteria to ranges of conditions favorable to human life? I used a 3-dimensional 3-deep grid (think rubics cube) to break down a planet to human habitability. The 3 dimensions and their depths: > > Surface Temperature (T): > > > * T1 = below 0C mean, 0C max over 90% of surface, liquid surface water would be mostly frozen, equatorial zone may be ok > * T2 = mean 0C to 40C, good for humans > * T3 = mean above 40C, 40C min over 90% of surface, generally too hot, polar/high altitude regions may be ok > > > Biosphere Favorability (B): > > > * B1 = little to no biosphere, or non-oxygen biosphere > * B2 = habitable biosphere, atmosphere mostly friendly to humans, minimal food and resources > * B3 = lush biosphere, edible plant-like and animal-like organisms > > > Hazards (H): > > > * H1 = little to no hazard to humans, or minimal protection required (dangerous sections of biosphere, small pockets of radiation, some harsh weather, large temperature ranges, etc) > * H2 = moderate hazard to humans, protection required (gravity, extreme weather, dangerous biosphere, hostile intelligence, high surface or solar radiation, corrosive or dangerous atmosphere or pressure or temp, etc) > * H3 = severe or extreme hazard to humans, substantial protection required, or too dangerous to even land > > > This gives you 27 combinations. I used a combination of English and Greek letters (with overlap) to format a grid. Greek letters and Y are for H3 worlds, J through Q are most optimal for human habitation or colonization. I skipped letters I O S Z because they look like numbers when written, and also U which looks like V. > > * A/Alpha: T1 B1 H3 > * B/Beta: T1 B2 H3 > * Delta: T1 B3 H3 > * C: T1 B1 H2 (The moon) > * D: T1 B2 H2 (Delta Vega) > * E: T1 B3 H2 > * G: T1 B1 H1 (Mars) > * H: T1 B2 H1 > * J: T1 B3 H1 > > . > * Gamma: T2 B1 H3 > * Lamba: T2 B2 H3 > * Sigma: T2 B3 H3 > * F: T2 B1 H2 > * N: T2 B2 H2 (Vulcan) > * P: T2 B3 H2 (Pandora, P3X888) > * K: T2 B1 H1 (Vorash) > * L: T2 B2 H1 > * M: T2 B3 H1 (Earth without humans) > > . > * Y/Upsilon: T3 B1 H3 (Demon class, Venus) > * Theta: T3 B2 H3 > * Omega: T3 B3 H3 > * V: T3 B1 H2 > * W: T3 B2 H2 > * X: T3 B3 H2 > * R: T3 B1 H1 > * T: T3 B2 H1 (P2X338) > * Q: T3 B3 H1 > > > Unfortunately this does not tell you about the complexity or intelligence of life. It would be easy to optionally categorize the most complex lifeform, and if there is intelligent life, its level of technological evolution. It does however do a pretty good job of telling you what to expect, or if you would need additional classification to determine if you should even enter orbit. [Answer] Maybe use Chinese characters. It would keep a creatively thoughtful SciFi mystique it all, much like how Firefly uses Chinese in its world. There are thousands of them, but, there would only be a limited set that is used most frequently for the most important-to-classify planets, such as habitable, dangerous, or mineral rich worlds. It would also be clever. ]
[Question] [ This question is, like [How long will it take to form a new dialect and language in underground steampunk London?](https://worldbuilding.stackexchange.com/questions/22688/how-long-will-it-take-to-form-a-new-dialect-and-language-in-underground-steampun), part of an experiment I'm conducting on Worldbuilding. I'm temporarily switching gears from linguistics to cartography, because an interesting issue has come up. --- The setting so far is Victorian London - with a twist. Around the year 1850, massive coal deposits were discovered underneath central London (construction on the London Underground began roughly 15 years before it did in our world, and large-scale excavations started up quickly). Within five years, even larger seams had been found, and it became apparent that London was sitting on top of the largest coal seam discovered to that date. By the year 1895 - the date of this story - the Underground project has expanded in conjunction with new mining enterprises, and there is effectively a second city underground, populated by workers and their families. I'm not entirely sure how deep it will run - certainly many hundreds and hundreds of feet - but it is quite sprawling. I'd like to create a map of the city, both to present with any stories taking place there and to use for my own benefit when planning other things out. In a normal city, this would be simple. This city, however, is composed of a sprawling network of tunnels, caverns, holes and other structures, all placed at different depths underground, thanks to a lack of collaboration between mining companies in the early days of the boom. How can I depict the whole city network in a two-dimensional map - with the technology available to a steampunk world (e.g. no computerized displays)? I've read the following questions, but I think that they aren't quite sufficient. * [How can I indicate a third dimension on a map of outer space?](https://worldbuilding.stackexchange.com/questions/18718/how-can-i-indicate-a-third-dimension-on-a-map-of-outer-space): Rooms, caverns, city blocks and tunnels cannot be represented simply, like stars can. They are also all interconnected. * [Graphically represent (map) multiple spatial dimentions](https://worldbuilding.stackexchange.com/questions/19107/graphically-represent-map-multiple-spatial-dimentions): This is close, but I'd like to not have to cut the map arbitrarily (or not so arbitrarily, e.g. at fixed depth intervals) because cuts could be straight through a large cavern, which would make for a disjointed map. * [Mapping a fantasy/horror building where rooms overlap](https://worldbuilding.stackexchange.com/questions/19301/mapping-a-fantasy-horror-building-where-rooms-overlap): I need to actually represent the various structures inside; a circle will not suffice to designate a cavern. [Answer] Use an isometric projection. [![enter image description here](https://i.stack.imgur.com/MlUKL.jpg)](https://i.stack.imgur.com/MlUKL.jpg) [Source](http://www.mrfs.net/trips/2008/Carpathians/Wieliczka/Wieliczka.html) This will let you depict multiple levels and whether tunnels link up with one another or not. This is a map for getting around, not for urban planning or measurements. It lets people get from A to B, but gives about as much perspective about the whole layout as any city map might. People living in [cubics](http://www.zompist.com/heinlein.html) might have better [non-Khan thinking](https://youtu.be/RbTUTNenvCY) and better understand the whole city from a map like this. If they're from the surface, you can draw the city over the top to let them "get a idea of the layout" in reference to the surface city they're more familiar with. [![enter image description here](https://i.stack.imgur.com/hOn7L.jpg)](https://i.stack.imgur.com/hOn7L.jpg) [Source](http://www.oobject.com/category/12-of-the-worlds-most-fascinating-tunnel-networks/) [Answer] ## Something like this... [![UnderLondon](https://i.stack.imgur.com/2czRG.png)](https://i.stack.imgur.com/2czRG.png) ## Depiction Choices The cartography of such a map as UnderLondon can choose whatever shapes they please to convey the needed information. The above map uses rhomboids to convey a sense of depth but note that Big Dome 300 has a different shape to indicate that it is, in fact, a giant domed cavern. Likewise, the shafts can be shown as thick lines instead of the very long rectangles. The number at the end of every label is a depth. This helps alleviate the problem of figuring out which parts of the city are higher or lower than another. The above map is made from the perspective of south looking northward. Careful layering or multiple maps might convey a fine-grained sense of which sections of town are further north or south. (Some dimension needs to get flattened and I picked north-south.) ## Assumptions * Slight changes in depth don't matter for people moving around, they just need to know which tunnels to take and which caverns to go through to get to where they want to go. Moving between strata in UnderLondon will matter to them. * Combined elevator/ventilation shafts will serve as the primary landmarks in the map since every other UnderLondon feature spreads out from these shafts. ## Map Requirements * In the event of an emergency, UnderLondoners will want to know the fastest way to get to the surface. * Navigation from the "town" to the coal seam will be of utmost importance. ## Mine Architecture Let's start with historical layouts of coal mines. In 1850, this was the layout of a coal mine in Maryland, USA. [![Maryland Coal Mine](https://i.stack.imgur.com/7YpNx.png)](https://i.stack.imgur.com/7YpNx.png) We can see that miners at this time already understood the need to support the [overburden](http://www.mcarthurrivermine.com.au/EN/Sustainability/Environment/Pages/Overburden.aspx) with relatively large pillars surrounded by tunnels of extracted coal. Analysis from the source article on [mine layout](https://en.wikipedia.org/wiki/Room_and_pillar) indicates that this particular layout doesn't have any clear ventilation planning which we will need if this underground city is supporting thousands or tens of thousands of people. [![Modern Mine Layout](https://i.stack.imgur.com/x9HjD.jpg)](https://i.stack.imgur.com/x9HjD.jpg) If the sprawling underground city of UnderLondon gets big enough, a map maker ought to include a link to the [Chislehurst Caves](https://en.wikipedia.org/wiki/Chislehurst_Caves) southeast of London. ## Graph Theory Explanation Any cavern, of any complexity or size can be described in terms of nodes and edges. Each cavern or intersection can be represented by a node and each tunnel is an edge. Elevators that touch several levels just look like really well connected nodes. Stairs are just parts of tunnels and don't appear on the map unless the stairs are really long. [Answer] # Use 50(or more) shades of grey. Start drawing the map from the lowest level. Map out everything in thick black lines. For higher levels, (closer to the surface) pick a grey color. Eventually as you get closer to surface level, you'll be using almost white ink. This allows for "layering" and depth of tunnels/structures based on the shade of grey used for that line. Since you've noted a lack of collaboration between mining companies, I suspect that this doesn't have to have extreme accuracy (assuming that it doesn't have to be "this is x meters underground", and "this is about 2 levels deeper than this" is acceptable). By using a white as you get closer to the surface and drawing the map from the lowest levels up, you ensure that you will be able to see the white on the black. Also, going from top to bottom doesn't make sense since you're covering up previous lines with each level, eventually resulting in being unable to see the levels that were drawn first. Note that the thickness of the lines is also very important. You'll want to have thicker lines for the lower levels, and thinner lines for the closer to surface tunnels, so that tunnels that run on top of each other can still be drawn properly without completely covering the lowest level. Note: depending on how deep you go, this is going to be a very convoluted map that would probably be hard to read unless the map was made really big... Here's what 3 tunnels directly on top of each other, but slightly different angled might look like (Made in Paint). [![enter image description here](https://i.stack.imgur.com/sBqXP.png)](https://i.stack.imgur.com/sBqXP.png) Here, we can clearly see the 3 distinctions of the tunnels - the black, dark grey, and light grey. Following the logic described previously, this shows that the black line is a single tunnel that is deeper than the dark grey, and the light grey is the closest to the surface. We can see that this method allows for all tunnels to be seen (even when multiple layers are all together - like I said, thickness is an issue and must be super precise) Here's a picture of what a small section of map could potentially look like: [![enter image description here](https://i.stack.imgur.com/zbz6m.png)](https://i.stack.imgur.com/zbz6m.png) In the above image, we have 4 layers, and it's easy to quickly distinguish which line belongs to which layer due to the shades of grey. The red dogs signify connection points between layers. For example, the topmost line is connected to the second layer at the bottom left red dot, and the second is connected to the third via the location pointed to by the right red dot, where the bottom layer is connected to the third at the top left red dot. Remember: Other colors or symbols can be substituted out for the greys/red dots. Perhaps this could be a point for your cartographers - some prefer to use circles to mark connections, some like dots, some like colors, some like greys. Alternatively.... # Use a 2D 3D map Try something like this: [![enter image description here](https://i.stack.imgur.com/iXok3.png)](https://i.stack.imgur.com/iXok3.png) The dark blue represents deeper layers. [Answer] Take a look at the user's map of the [London Tube](https://en.wikipedia.org/wiki/File:London_Tube_Map_May_2015.png), and compare it with the [actual map](https://commons.wikimedia.org/wiki/File:London_Underground_with_Greater_London_map.svg). The user's map shows the stations and their connections, and those stations are in roughly the right place. This is close to the suggestion by Green (which I upvoted), but it isn't pure graph theory. [Answer] # Get artistic. Hire an artist. Get them to draw, in perspective, a projected map of the city. It'll end up looking sort of like an isometric projection (as in Samuel's answer), but with sufficient detail, you can show passages going over and under one another, and coming out in the right places. Combine this with cutting away walls and/or ceilings to show the insides of caverns and the like (so you can see the connections), and you've got yourself a map. # Use contours. Like on real-world maps, use lines that designate a height. Have one line be 0 feet elevation, the next -10f, -20f, -30f etc. They should be drawn in a conspicuous color, and should go over the parts of the underground network that are at that height. # Combine the two. Take your isometric artistic project from the first point, combine it with contours from the second, and you'll have an easy to understand map of the underground which clearly demarcates the elevations it's all built at. [Answer] A couple of possibilities - either colour code outlines by depth (like aify's shades of gray idea, but using outlines rather than filled shapes (and maybe colour rather than grays). That way if you have two corridors/rooms over each other, you can just use concentric outlines so you can still see both. The other possibility is to use stereo cards and a stereoscope for a true 3D view (from a fixed viewpoint). They were popular in Victorian times, around the 1850s, so they're certainly appropriate technology. (for some examples of how these work and some 1850s-1860s stereograms, have a look at the London Stereoscopic Company website (<http://www.londonstereo.com>) - you can see a couple of modern versions of stereoscopes, and the A Village lost and found and diableries are examples of 1850-1860s material. As well as photographing things, you could also draw them (though that would take some skill). For use without a stereoscope, you could probably also use red/cyan anaglyphs - where the images for left and right eyes are printed on top of each other, one using red ink, the other cyan, and viewed using the old style 3d glasses with one side red and the other cyan - the idea being to block the view of the "other side" image for each eye. Lenticular 3d cards use cylindrical plastic lenses - patented in 1936, they're probably too modern (and use plastics) for an 1850s setup. ]
[Question] [ I'm curious what the gravity would be like on an infinite area flat world. The plane of the world would have some finite depth but be infinite in all cardinal directions. This is, in effect, a Minecraftian world. This is expanding on the ideas presented in [this question](https://worldbuilding.stackexchange.com/q/12378/3202). How deep would the world have to be in order to have a surface gravity identical to Earth? [Answer] It would be 6,378km deep. The same depth as the radius of the Earth. The math To calculate the gravity of an infinitely flat plane we simply need to integrate the force felt from concentric rings from a radius of zero to infinity. ![enter image description here](https://i.stack.imgur.com/VHy33.gif) This is a basic practice in college physics courses and is [demonstrated here](http://www.mathpages.com/home/kmath530/kmath530.htm). It turns out, that the force on a mass above the plane is equal to: $$ F = 2\pi Gm\rho\_a h \int\_0^\infty {{R}\over{(h^2+R^2)^{3/2}}}dR = 2\pi G \rho\_a m $$ Thus, the force does not depend on distance from the surface! This makes sense because the further away one gets from the plane, the more of the gravitational force vectors from the surrounding mass point back toward the plane. That is, the vertical component of all the gravity vectors become larger. The only factors that matter for the force are the gravitational constant, the density of the plane, and the mass of the object. Lets leave the gravitational constant alone and fiddle with the density of the plane. The mass of the object doesn't matter here, but it can be set to one for simplicity. The density In order for the gravitational force to be the same as Earth gravity, we need to set $2\pi G \rho\_a$ term equal to $9.8{{m}\over{s^2}}$. This comes from $F = ma$, where $m$ is the mass of the object and $a$ is the acceleration due to gravity. Thus, $\rho\_a$, the mass density per unit area needs to be $2.34 \* 10^{10} {kg\over{m^2}}$. That's really high, but let's see where it goes. The depth This plane is infinitely thin, so the mass density is per unit area, not unit volume. This not actually an issue, it's trivial to see that adding another infinite plane below this first one will simply add gravitational force. That is, it doesn't actually matter if the plane is infinitely thin or a kilometer thick, it only depends on the mass density of a slice of that plane. From volume We know the density of the earth (as in dirt, rocks, etc. - the material of the plane) in terms of volume, but what about area? The conversion is $\rho\_v = {{\rho\_a}\over D}$ where $\rho\_v$ and $\rho\_a$ are mass density for volume and area respectively and $D$ is the depth of the plane $^1$. So, if we're going to use volume density in place of the area density in the equation, it needs to be multiplied by the depth. Don't scoff yet, this works. Earth's average density is $5540 {kg\over m^3}$, but the crust where we live has a density of about $2700 {kg\over m^3}$. Let's mix it up a bit and make the world a little iron rich and say the density is $3668 {kg\over m^3}$. If the surface density is $2.34 \* 10^{10} {kg\over{m^2}}$ and the volume density is $3668 {kg\over m^3}$ then the depth must be 6,378km. That's radius of the Earth. Ok, so I fudged the density to get that answer. Big deal. Select any density you like and change the depth to work. From force Want to double check that? We can agree that, given a surface density of $3668{kg\over m^2}$, the gravity above the plane from the first equation would be $1.538 \* 10^{-6} {m\over{s^2}}$. A very small amount of gravity. But then how thick is the plane? I say one meter, see footnote 1. Though any thickness works, but our units are already in meters, so why not. Now, we can also agree that if an identical plane was anywhere below this first one, its gravitational force would add with the first. Just like how all the dirt below us adds to the total gravity we feel. Recall that the distance from the infinite plane doesn't matter, the gravity is the same all the way up. So how many of these one meter thick planes need to be below the top one to sum to a force of $9.8{{m}\over{s^2}}$? You guessed it, 6,378,000, or 6,378km deep if stacked one on top of the other. $$1.538 \* 10^{-6} {m\over{s^2}} \* 6,378,000 = 9.8 {m\over{s^2}}$$ Wait, what about 1/2 meter planes? Ok, well 1/2 the density and two times the number of planes then. Same depth, same gravity. Wait, what about 1/x meter planes? Ok, well 1/x the density and x the number of planes then. Same depth, same gravity. Fun fact The gravity extends infinitely in all directions. This means that both sides of this world will have Earth surface gravity. The people that live on the other side are called Australians. Footnote 1: The mass of one of the slices is equal to the mass density per unit area times the area, $M = \rho\_a A$. The mass density of a volume is mass per unit volume, $\rho\_v = {M\over V}$. Volume can be expressed as area times depth, $V = A\D$. So we can say the mass density of the volume is $\rho\_v = {M\over {A\D}}$ The volume density of the plane would then be, $\rho\_v = {{\rho\_a A}\over {A\*D}}$ or $\rho\_v = {{\rho\_a}\over D}$. For a depth of 1 meter then, mass density of the volume would equal the mass density of the area. [Answer] If I may, I'll make a slightly simpler (I think) derivation of the answer. We start with [Gauss's law for gravity](https://en.wikipedia.org/wiki/Gauss%27s_law_for_gravity). In its integral form, it is $$\oint\_{\partial V}\mathbf{g}\cdot \mathrm{d}\mathbf{A}=-4\pi GM$$ Here, $\mathbf{g}$ and $\mathrm{d}\mathbf{A}$ are vector quantities of the gravitational acceleration and an infinitesimal vector change in area. $\partial V$ is part of the surface area encompassing a volume - in this case, a [Gaussian pillbox](http://ocw.mit.edu/high-school/physics/exam-prep/electrostatics/gausss-law/8_02_spring_2007_chapte4gauss_law.pdf) (see Example 4.2). Since the surface is presumably of uniform surface density, $\mathbf{g}$ must be the same throughout any region, and therefore $\mathbf{g}$ is independent of $\mathbf{A}$1. Using this, we can write the integral as1 $$\int\_{\partial V}\|\|\mathbf{g}\|\|\text{ }\|\|\mathrm{d}\mathbf{A}\|\|\cos\theta=-4\pi GM$$ because $\theta=0$, and so $\cos\theta$ goes to $1$. We then get $$\int\_{\partial V}\|\|\mathbf{g}\|\|\text{ }\|\|\mathrm{d}\mathbf{A}\|\|=\|\|\mathbf{g}\|\|\int\_{\partial V}\mathrm{d}\mathbf{A}=g(2\pi r^2)=-4\pi GM$$ where $g=\|\|\mathbf{g}\|\|$. The factor of $2$ came about from the use of the Gaussian pillbox for the area. We then have $$g=-\frac{4\pi GM}{2\pi r^2}=-2\pi G\frac{M}{\pi r^2}=-2\pi G\sigma$$ where $\sigma$ is the surface mass density, Samuel's $\rho\_{\alpha}$. We've gotten there by slightly different means than [Samuel's answer](https://worldbuilding.stackexchange.com/a/12443/627), bypassing that integration (which really isn't too bad). We've also used the postulate that $\mathbf{g}$ (and thus $g$) is independent of location, which makes perfect sense on an infinite plane. From here, it's easy to find the height of the plane, using $$\rho=\frac{\sigma}{h}\to h=\frac{\sigma}{\rho}\approx R\_{\text{Earth}}$$ This is a direct analog of finding the charge density on an infinite plane - or doing the reverse, finding the electric field in a point on an infinite plane due to a charge density. Likewise, we can give the infinite plane a density, and then find the gravitational acceleration at its surface. --- 1 For two vectors $\mathbf{a}$ and $\mathbf{b}$, the [dot product](https://en.wikipedia.org/wiki/Dot_product) is equivalent to $$\|\|\mathbf{a}\|\|\text{ }\|\|\mathbf{b}\|\|\cos\theta$$ where $\theta$ is the angle between $\mathbf{a}$ and $\mathbf{b}$, and $\|\|\text{ }\|\|$ denotes the magnitude of a vector. ]
[Question] [ Somewhat in relation to this question - [What could restrain post-singularity societies from spreading across the Galaxy?](https://worldbuilding.stackexchange.com/questions/4918/what-could-restrain-post-singularity-societies-from-spreading-across-the-galaxy) I'm assuming not all star systems move at the same velocity in relation to the speed of light...some stars will be moving quicker and therefore the planets around them will also be moving quicker (if this assumption can be challenged, please do). Since time is directly related to the difference between a body's speed in relation to the speed of light, it would stand to reason that one colony could experience 100 years in the same span another colony only experiences 99 years. Let's say in a distant future, humans colonize a few other star systems. These star systems are moving at different speeds relative to each other. * What speed difference would there have to be between stars for a 1% time difference? Is it feasible that humans could populate a star that's moving that much faster (or slower for that matter)? * Is it possible that another race could originate from a star that has only seen a few hundred thousand years while our earth has experienced 4 billion? Just to give the background...I have the vision of an ancient race whose star saw its end. They relocated to a star moving significantly slower than the majority of those in the galaxy, and as such the galaxy around them aged quickly while they saw a relatively short time span pass. How feasible is this? Can the speed of stars vary enough to create a pronounced effect on the passage of time between two systems, or does the variation in speed become too great to actually see a noticeable effect? [Answer] A 1% change might be feasible, but dramatic variances are unlikely. Time dilation only becomes significant as you start approaching the speed of light. You have to be moving almost 0.2C to see a 1% difference. While a star system moving at any velocity is possible in a theoretical sense, in reality I don't think you'd encounter systems moving at anywhere near the necessary speeds to see dramatic time differences. To put this in persepective, the speed of light is 299,792 KM/s. Our solar system revolves around the center of our galaxy at about 250 KM/s. Or less than 0.001 C. Another system would have to be moving (relatively) 200 times faster than ours for even a 1% difference. Here's a graph that shows the time dilation effect at a given speed. The horizontal axis is the speed, in terms of C. The Vertical axis is the factor of the time dilation. ![enter image description here](https://i.stack.imgur.com/IHjjz.png) (Wikipedia <http://en.wikipedia.org/wiki/Time_dilation>) [Answer] You wrote: > > Just to give the background...I have the vision of an ancient race who's star saw it's end. They relocated to a star moving significantly slower than the majority of those in the galaxy, and as such the galaxy around them aged quickly while they saw a relatively short time span pass. > > > How feasible is this? > > > Not very. It does depend on a few things, though. # Velocity time dilation According to special relativity, an object moving relative to another measures time differently; this phenomenon is known as time dilation. An observer in motion measures a time interval $$\Delta t'=\frac{\Delta t}{\sqrt{1-v^2/c^2}}=\Delta t\gamma$$ where $\gamma$ is known as the Lorentz factor and $\Delta t$ is the interval measured by a stationary observer. We should be able to compute $\gamma$ for any star in a galaxy. Stars don't orbit like a rigid body rotates (e.g. where their tangential velocity is proportional to their orbital radius). Similarly, they don't have Keplerian orbits. In reality, they follow rotation curves - plots of velocity as a function of radius - that are complicated, thanks to both dark matter and the fact that the galaxy isn't a point mass. I decided to look at some real data, so I turned to [galkin](https://github.com/galkintool/galkin) (more information [here](http://ascl.net/1711.011)), which has data from a large number of observations of the Milky Way. In particular, it generates rotation curves from data from gas clouds, masers, and stars. I took the speeds of the stars tangent to the galactic center as computed by galkin. I first plotted a rotation curve, which is fairly flat beyond $r=5\text{ kpc}$.: [![Milky Way rotation curve](https://i.stack.imgur.com/pyQd3.png)](https://i.stack.imgur.com/pyQd3.png) I then calculated $\gamma$, the Lorentz factor, relative to a stationary observer at infinity: $$\gamma=\frac{1}{\sqrt{1-v^2/c^2}}$$ where $v$ is the star's tangential velocity. As expected, $\gamma$ is close to $1$ for all $r$; there is little time dilation due to the motion of stars. [![Milky Way Lorentz factor](https://i.stack.imgur.com/WQSqt.png)](https://i.stack.imgur.com/WQSqt.png) # Gravitational time dilation Time also flows at different speeds for an observer in a gravitational field. The galaxy's gravitational field isn't large, and so we can apply something called the [weak field limit](https://physics.stackexchange.com/a/246460/56299): $$\Delta t'\approx\Delta t\sqrt{1+\frac{2\Delta\phi}{c^2}}$$ where $\Delta\phi$ is the difference in potential between two observers. To compute the potential, I used a model by [Flynn et al. 1996](http://adsabs.harvard.edu/abs/1996MNRAS.281.1027F). It reproduces the observed rotation curve very well, using a three-component model: [![Gravitational potential of the Milky Way](https://i.stack.imgur.com/FsPeN.png)](https://i.stack.imgur.com/FsPeN.png) [![Reconstructed velocity curve](https://i.stack.imgur.com/34xx4.png)](https://i.stack.imgur.com/34xx4.png) By setting an observer at infinity, I let $\Delta\phi=\phi$, and thereby calculated the proportionality constant at all $r$. It turns out to be quite close to $1$, meaning that there is very little gravitational time dilation. [![Proportionality constant](https://i.stack.imgur.com/1bH4n.png)](https://i.stack.imgur.com/1bH4n.png) [Answer] I am not a physicist, so take this with several grains of salt, but... Your basic assumption is wrong, all "frames of reference" have the same velocity in relation to the speed of light. This is what causes relative velocity time dilation, actually, so you can't even hand wave it away. (Otherwise, FTL travel might help.) The consequence of this would be that both systems would have the exact same velocity difference in relation to each other, and consequently, the exact same time dilation in relation to each other. The effect would be symmetrical. Basically your question is malformed in the sense that it is the changes in velocity made by travelers, not the difference in the constant velocity of planets, that matters. This is the classical "[twin paradox](http://en.wikipedia.org/wiki/Twin_paradox)". Just as you'd like this would result in the time having passed more in the galaxy, than for the travelers. But there is a rather big issue. The effect relies on the traveler having made two relativistic trips. Or in short, you can't use FTL. You'd have to use some slower than light method of travel, and I don't think that getting the time dilation you want is really practical with STL. It would simply take too long. And really only be useful for single trip (for story purposes). And require unrealistically efficient engines. On the other hand, if you assume FTL, you can fiat rule that time passes slower in FTL, and say that the ancient civilization actually escaped there... [Answer] GrandmasterB provided a good answer concerning time slowing down due to high velocities. Let me fill the gap with the gravity. Time dilatation in gravitational field is given by the [Schwarzschild metric](http://en.wikipedia.org/wiki/Schwarzschild_metric). From it follows that the factor that gives you how much slower the time flows is $$ \delta t=\sqrt{1+\frac{2G M}{R c^2}}\;, $$ where $c$ is the speed of light, $R$ is radius of the planet, $G=6.672\cdot 10^{-11}\;\mathrm{s/kg}$ is the gravitational constant and $M$ is mass of the planet in kilograms. So for example for Earth, time flow rate differs by 0.9999999993 compared to space. (I.e. there is almost no difference). To get more general estimate that is very nicely imaginable and can be approximately used for any place in the galaxy, we can use interesting fact, that for Scwarzchild solution, the escape velocity is [given by the same formula as for the Newton's gravity](https://physics.stackexchange.com/questions/33916/what-is-the-escape-velocity-of-a-black-hole), $$ v\_e=\sqrt{\frac{2GM}{R}}\;. $$ Putting these equations together, we can calculate that the time slowdown at given place is given by the escape velocity to infinity like $$ \delta t=\sqrt{1-\frac{v\_e^2}{c^2}}\;. $$ Interestingly, this is the same formula as in the special relativity for time dilatation GrandmasterB plotted in his answer! Escape velocity from our galaxy is [approximately 500 km/s](http://en.wikipedia.org/wiki/Escape_velocity), so time here flows 0.9999986 x time in the intergalactic space. So, unfortunately, you do not get any significant time shifts unless you are really close to neutron stars or black holes. [Answer] some problems (or, perhaps, opportunities) that would have to be possible: 1. if the ancients wanted to hop from one world to another that happens already to be moving at near light-speed, they would have to have a way of attaining that kind of speed themselves, so that they could then land on the planet. 2. until they reach that kind of speed, I suspect it would be very difficult for them to even detect the existence and location of such planets, because they're moving so fast. 3. they would also have to happen to be moving in a direction that brings them closer to the planet. 4. would they have to be on a course that intersects the planet's trajectory, so that they don't have to be moving at faster than light speed in order to catch up to it? [Answer] Reports of the fastest objects in the universe [1,2] posit that there could exist planets that travel as fast as 30 million miles per hour, or 0.04473 times the speed of light. This works out to a small but noticeable time dilation. When 1000 days have passed in the rest of the universe, only 999 days have passed on the high-velocity planet. [3] In a hundred years, only 99 years, 10 months and 24 days pass on the hypothetical planet. [1] <http://bit.ly/1BubVsW> [2] <http://bit.ly/1IkdFFs> [3] <http://bit.ly/1tFtDmO> [Answer] You have to consider two points when comparing two stars systems. First is the relative Velocity of the solar system in respect to another. (as relative velocity increases it slows down time), then you have to consider a gravitational field (provided by the mass of a solar system). Time dilation in a gravitational field does not depend on the local strength of the field, but rather "how deep you are inside" one. If the gravitational field is nearly uniform, so that it is almost as strong way up high as it is near the ground, then there will still be gravitational redshift of light climbing up against gravity. (the influence of time dilation in a gravitational field is negligeble unless you are orbiting close to a neutron star, blackhole). So two differen systems lets imagine a massive star and a white dwarf both at speed differences and different gravitational fields would create a difference in the passage of time relative to each other. Processes in the slower less masive star system will happen slower relative to the small solar system. [Answer] \\the time will always be calculated by rotations, a full planet rotation would be a day that can be > or < than an Earth day. A year would be also >/< than an Earth year. The average speed of a stellar system would be +/- X % of the Solar System. The average onward-propelling speed will also be +/- Y %. one cannot talk about clocks any more, as, in human terms, we will be living within biological time, limited by stellar-dependant time/s that could be measured by time indicators: 1. indicator of the Earth time (etalon); 2. indicator of the Stellar System; 3. indicator of the Constellation/s; 4. inner-spaceship indicator; 5. average time indicator; 6. etalon human life indicator; 7. individual human biological indicators. Ivan Petryshyn ]
[Question] [ In a hypothetical world where multiple humanoid races develop independently of each other (such as a world that contains Elves, Dwarves, and Humans for instance) what are the conditions for half-breeds to be possible? In our world; * Dogs can produce offspring by mating with any other breed within their species, producing half-breeds or "mutts" which can create whole new breeds and continue reproduction. * Horses and Donkeys can breed together to produce Mules, which cannot reproduce on their own. * Animals from very different species can not breed together, such as an Elephant and a Giraffe. * Humans can breed with other Humans, but not with Monkeys or Apes with whom they share ancestry. Under what conditions could a new "half-breed" race develop between two races? (Such as Humans and Elves creating Half-Elves) One that would be consistent in it's outcome, (A Human and an Elf always breed a Half-Elf) and the resulting offspring's race. (Half-Elves are always the same). One that would also prevent continuous branching. (Like Dog breeds which continue to create new breeds all the time) [Answer] The one answer that doesn't involve outright magical hand-wavery is common ancestry. Whatever caused the species to split into separate races or even species occurred long enough ago, and the resultant groups were isolated from one-another for long enough that they changed in different ways. When they eventually came back into contact with one-another, sufficient genetic similarity exists in order for crossbreeding to be possible, though it is frequently the case that such crossbreeds - if the divergence is sufficient - are not fertile themselves. With greater divergence, reproduction is not usually possible at all. In a magical environment, however, magic can be used to explain the speed and nature of the divergence, without having to say that magic explains that (for example) "This species that evolved from lizards can successfully cross-breed with this other species that evolved from trees". The [Oath of Swords](http://en.wikipedia.org/wiki/Oath_of_Swords) series of books by David Weber is a fantastic example of this; the various humanoid species/races each have a logical explanation of how they diverged from basic human stock, even in a magical environment. [Answer] ### Preamble Two suggestions on how one could acquire the effects (consistency, half-elves are always the same) with something that resembles real-life genetics. Note that this is based on school knowledge only and probably not evolutionary plausible. In both variants, I use special genes which determine whether somebody is an elf, halfling, half-halfling or whatever. It might be more plausible if those were whole [allosomes](http://en.wikipedia.org/wiki/Allosome), i.e., special chromosomes, which do not participate in [chromosomal crossover](http://en.wikipedia.org/wiki/Chromosomal_crossover) (like the human Y chromosome). I use dwarves and elves as an example. ### Variant 1 There is a gene which comes in two types of alleles: `D` and `E`. The phenotypes corresponding to the genotypes are: * `DD` – dwarf * `EE` – elf * `DE` – dwelf (half elf, half dwarf) Thus we get the following probabilities of results upon breeding: * Dwarf and dwarf – 100 % dwarf * Elf and elf – 100 % elf * Dwarf and elf – 100 % dwelf * Dwelf and dwarf – 50 % dwelf, 50 % dwarf * Dwelf and elf – 50 % dwelf, 50 % elf * Dwelf and dwelf – 50 % dwelf, 25 % dwarf, 25 % elf. Thus, you get what you asked for in the question. But the effect that dwelves may breed something other than dwelves may be undesired. ### Variant 2 There is a gene which comes in three types of alleles: `D`, `E` and `0`. The phenotypes corresponding to the genotypes are: * `D0` – dwarf * `E0` – elf * `DE` – dwelf (half elf, half dwarf) * `DD`, `EE`, `00` – results in early miscarriage. This may sound more drastical than it is: It is estimated that half of all human pregnancies result in early miscarriages which are not even noticed as such but are perceived as irregularities in the menstruation cycle (which is why this number can only be roughly estimated). We get the following probabilities of results upon breeding: * Dwarf and dwarf – results in 50 % miscarriages (`DD` and `00`) and 50 % dwarves. * Elf and elf – results in 50 % miscarriages (`EE` and `00`) and 50 % elves. * Dwarf and elf – results in 25 % miscarriages (`00`), 25 % dwarves, 25 % elves and 25 % dwelves. * Dwelf and dwarf – results in 25 % miscarriages (`DD`), 25 % dwarves, 25 % elves and 25 % dwelves. * Dwelf and elf – results in 25 % miscarriages (`EE`), 25 % dwarves, 25 % elves and 25 % dwelves. * Dwelf and dwelf – results in 50 % miscarriages (`DD` and `EE`) and 50 % dwelves. You give up that dwarf and elf always results in dwelf, but dwelf and dwelf always results in dwelf. [Answer] This is actually not too hard to do, or at least this part isn't. The hard part is having two sentient races evolve at all, but even that I don't think is as hard as people think. All you need is for your Humans and Elves to have a (close) shared humanoid ancestor, to effectively be the same species the same way a poodle and a wolf are and the genetics works perfectly fine. The short answer is to have the a starting humanoid species that is cut off from other humanoids for a decent length of time (but not too long) allowing them to grow and develop on their own. Each of these humanoids would adapt differently to their enviroment, growing different traits that made them different races. You simply need to make sure that they were isolated for awhile before the meet up again (at which point koinophilia would ensure they stayed separate races). Easiest would be to go with the idea of migration of your primitive humanoid over land bridges that later got swallowed by the ocean, just as African people expanded to the Americas & Australia etc. Except make sure that they spent a bit longer on these separate land masses, long enough to develop into more distinct species rather then just humans with slightly different skin color or facial features as on Earth. Once they met up they would be almost exactly as you described in how their mating would work. The only hard part here is keeping them separate long enough to become distinct 'races'. The original primitive 'humanoid' they all evolved from would likely have to be sapient, or at the very crusp of it, for these species to all be sapient. However, once sapience is reached technology starts evolving and very quickly (from an evolutionary stand point) they get boats and other means of traveling and meeting up with other races, which limits the length of time you have for the species to adapt. If you cared to get that deep in thought I would either make up an excuse why they early humanoids were slower to develop technology or create some strong environmental influences that would push the humanoids to evolve in differently quickly. Now, to get into the more detailed sciency discussion of how the evolution would work, and why this is 'easy'. But first lets assign a naming convention, I'm going to use 'race' to refer to creatures that can mate to produce viable fertile offspring, even if habitat or mating behaviors would prevent it normally, but are clearly vastly different in phenotype, such as dog breeds or your elf vs human, so by race I'm implying a bit more then just a different skin color as it means on Earth. Mutts vs Mules As you said you don't expect genetically different species to interbreed, no dog/horse hybrids. However, genetically similar species can often produce offspring, rather or not that offspring is fertile. There are lots of factors that affect rather two creatures can produce offspring at all, I won't get into any other then chromosome number for now, but as a general rule of thumb closer genetics mean more viable offspring. This in turn means the closer evolutionary they are, ie the shorter the length of time between when the species had a shared evolutionary ancestor, the more likely the are to be viable. Of course the closer they are evolutionary the more similar they usually appear, which is why it's usually easy to identify creatures that might be able to interbreed just by looking at them and seeing how similar they look. However, let's focus on the concept of fertile offspring, since I assume you want your hybrids to be able to produce hybrids of their own. To go with your first two examples of mutts and mules, why are they different? Why can dogs, or in fact most canines, interbreed to produce fertile offspring, but not horse and donkey? Genetically equines are similar, having a shared ancestor not too far back evolutionary, and can safely (mostly) produce offspring with each other easily, the offspring is just usually infertile. They are genetically viable, the problem is chromosomes. These equines offspring usually have an odd number of chromosomes, resulting in fertility issues. This is because equines all have a different number of chromosomes, 64 for horses, 62 for donkeys, and 32-46 for zebras. Thus while genetically very similar, and able to produce offspring (zedonks, zorses, mule, Hinny etc) their offspring will usually be infertile due to having the 'wrong' number of chromosomes (little over simplified here but good enough). Equines last genetic relative was 4 to 4.5 million years ago, far less then the time between human and apes. Dogs, and in fact most major canines, all have exactly 78 chromosomes. Thus they can all interbreed with each other because their offspring will always end up with 78 chromosomes as well. In short, so long as everyone keeps the same chromosome number they can be different 'races'. Of course canines last genetic ancestor was around 40,000 years ago, a blink of an eye in evolutionary time, which is part of why they have not had time to diverge more. Human species, races, and humanzee Now to your last example, why can't humans interbreed with apes? Our last genetic ancestor with chimps (including bonobo) was six to seven million years ago. However, that doesn't mean we aren't compatible, genetically were very similar. Look at bonobo and chimpanzee, our two closest genetic relatives. They are able to produce fertile offspring, quite easily, though they 'only' have been separate for 2 million years. In fact, if you look at our genetic difference compared chimp/bonobo we are about as different as equines are! That's right equines, who can produce offspring (some pairings a bit harder then others, but all can). So shouldn't we be able to produce offspring with apes? A large part of the problem is again with chromosomes, and humans causing trouble. Some time in our history, after splitting off from apes, two of our chromosomes fused together into one chromosome. This means we have exactly one less chromosome then apes, and different number of chromosomes make mating much harder. This is a large part of why we are incompatible with apes. However, Equines also have a different number of chromosomes and produce hybrids semi-easily. So then why aren't we still at least semi-interfertile? Who knows, we can't point to a specific reason that makes us entirely infertile with apes. It basically comes down to how our chromosomes have changed. Presumably some random mutations happen to be less compatible with apes than would be expected. Actually, we can't say with 100% certainty we aren't capable of producing hybrids with apes, in theory. We're almost certainly not usually inter-fertile, but many species generally thought to be less fertile have had random successful mating. Certain studies rule out fertility with non-apes but in theory we can't say for certain that a rare hybrid with chimp/bonobo isn't possible. After all, mating between human and bonobo don't happen very often, so if there was a 1/1000 chance of a hybrid it would take quite a while for that to actually lead to a hybrid being produced, and we may not catch it when it happens. However, I'd say the odds are pretty slim :) However, my point is that our lack of fertility with apes is almost as much a fluke as a rule. If our chromosomes hadn't decided to fuse we may be making monkey hybrids left and right. Generally speaking we are more divergent evolutionary from apes then equines and canines are from each other, which no doubt plays a role, but it comes down partially to chance and how mutations played out. Different humans on a parallel earth may very well have been fertile with Apes if a few mutations happened differently. Proto-human love Of course that doesn't mean we weren't fertile with any apes. Before Homo Sapiens showed up many other homo-whatevers existed, proto humans, and many of them interbred. Most interesting, humans interbred with our close genetic relatives, the neanderthal! That's right, in our not-that-distant-past we had two races of humanoids, homo sapiens and neanderthal, with very real physical differences. Both species were intelligent, arguably sapient, used tools etc etc, their differences were just the same as elf and human; or perhaps elf and troll (neanderthal were larger, stronger, and better equipped for running, but needed more food due to this, which may have been part of how we ended up outcompeting them). These two races produced hybrids, and those hybrids stayed and mated with their parent species, we know this because we have found neanderthal DNA in modern humans. Thus we already have your perfect example having happened in our own history. Sure the Neanderthal died out, but nothing said they had to. If they had adapted a little better to the pressures that killed them they may have lived on to develop into a more 'modern' race. Of course it's possible our interbreeding is what 'killed' them, that eventually they became part of humans rather then being a separate race, who knows. The point is that races that can interbreed the way you want are common, it is random fluke that humans are not compatible with other species. Your multi-race world existed in the past, but humans ended up being the only ones that made it to the modern era. If other sapience humanoids managed to survive to modern era we would be able to produce cross-breeds just like you suggested. So how do we make them survive? So the real question is simply how to ensure multiple sapient species survive. My suggestion is to isolate them from each other, as I already said having them migrate to different continents and then be cut off from their home continent is the easiest option. If you want 'underground' races (dwarf, gnomes, etc), that's easily done by making them simply have found a niche living underground and evolved for it as well. The thing you need though is to keep them separated for awhile, so they have time to change without interbreeding. This is how any species comes about, the two species need to be isolated for mutations in each group to not spread to the other group long enough for those mutations to make them distinct entities. Particularly in the case of sapient species this isolation likely becomes a bit more important to think about, since we would find ways around many things that isolate other species (Bonobo and chimp are genetically viable and live practically on top of each other, the nile separates them. A simple technology in their past and there would be no difference between the two because they would have interbred). You also need the separation length of time to be long enough, thus why I tried to show the length of time between the common ancestor of each species. the canines are 40,000 years apart and interbreed easily, but are also so similar it hardly seem far enough apart to be a different race (I'm talking wolf vs coyote etc, dogs are vastly different due to human breeding and thus shouldn't be looked at for an example of 'natural' evolution). So I would look at making sure you kept your humanoids separate for at least 40,000 years. Equines with 3 million years apart are a bit too genetically different, so you probably don't want your species separated that long, but that isn't an issue,. Your problem is keeping a nearly-sapient species from developing boat technology in 40,000 years. Once sapience is achieved technology will develop rapidly. I would suggest further picking the features of your different races you want to be distinct and come up with a justification why they were evolutionary advantages. The more significant an advantage these are the easier it is to justify their evolution rapidly. However, I think this is pretty easy to handle, and is also more a world-building question about how to allow multiple sapience to evolve at this point. The key part is that they will interbreed once they evolve without any real work, it's how their genetics will exist. Genetic curiosities of your hybrids Blanket term, but having gone over how they could evolve lets talk about some interesting details that factor in to such species. Not all must be fertile As I said humans were kind of odd in that we really didn't need to be as infertile with apes as we ended up being, it is unusual that we are less fertile with chimps then one would expect. However, it's not impossible for this to happen with other species. You could have some humanoids that are not fertile with others. Or, like equines, you could say some humanoids have a harder time producing offspring together but can. Perhaps human-orc hybrids are common, but elf-gnome hybrids are very rare. You have some wiggle room to affect how easy hybrids are produced for a given combination of races, though as a general rule of thumb most races will be mostly inter-fertile and only a few combinations will struggle with producing offspring most likely, owing to how close their most recent common ancestor likely was, due to the whole sapience means technology comes fast argument from earlier. Going along with this it's also possible to say some hybrids are not fertile while others are, or then some hybrids usually aren't fertile, but with varying chance of fertility. The more time you put between humanoid's last common ancestor the more you can get away with these sort of incompatible hybrids, most will be compatible without issue. Due to [Haldane's rule](https://en.wikipedia.org/wiki/Haldane's_rule) if you decide to have some hybrids that are not always fertile it's the males that will usually be infertile, while females may still be fertile. Likewise when hybrids that are rare a hybrid will be far more common if the father is from the species with fewer number of chromosomes. I don't expect you to know how many chromosomes your races have, but the point is that if a hybrid is rare one cross (race x father with race y mother) may be more common then the other (race y father with race x mother). I'm so depressed to be a cross-breed There is a concept called [Outbreeding depression](https://en.wikipedia.org/wiki/Outbreeding_depression), which basically says that if two organisms are very different then a child produced by them is likely to be less viable then a child produced by two parents that are more similar. This principle is not limited only to hybrids, but is most evident with them. Not all species will suffer outbreeding depression, some may even experience the opposite phenomena of inbreeding depression, but generally outbreeding depression is more common. Outbreeding depression can be caused by many reasons, but there are two big ones. 1. Races evolve to fit niches, but if a hybrid is halfway between two races he is half way between two niches, not fitting in to either. This often hurts him because he can't survive in either niche. Imagine a half human, half dwarf. He may lack the vision to see in the dark of a mountain and instinctual be claustrophobic, making him unable to live with dwarfs. However, his small stature, without the equivalent dwarven strength, may make it hard to live in a human village where everything is built for someone taller, thus he struggles in both areas. 2. Genes don't match up perfectly. Race X may use a gene to regulate some trait and race y a different gene, a hybrid of the two may fails to get either gene, causing something to be out of kilter. For example, in dogs you never ever mate a large male to a tiny female. They will happily mate (dogs have been bred to be very...sexually liberal?), and the male often will find a way to do the deed even if he seems too big. However, the pups will have genetics deciding their size based off of both parents, meaning they will grow to be roughly half way between size of mother and father. The problem is that the mother, and her womb, are still much smaller then that size. This means that the pups will effectively grow too large to fit within her womb, dying when they run out or room to grow and quite possible killing the mother in the process. The combination of genes clearly had very unfortunate side effects even if they could breed. You should keep this in mind, the hybrids will likely struggle compared to 'pure-bread' species. In particular I would remember example 2, that some oddities may show up when mated together. However, outbreeding depression can occur rarely at times too. Some traits may be better off for hybrids then the pure-breeds, this is just less common the the opposite. For instance zebra-horse hybrids were bred because they were more tolerant to diseases than either parent species in certain areas of the world. And mules are bred because they are strong while still being more even-tempered than donkeys. Generally speaking when outbreeding helps it will be in one or two unique areas, not necessarily everywhere. The Zorse for instance was more immune to disease, but was generally less useful as a pack animal than a horse otherwise. Just because your hybrid gets one or two odd positive traits, (better eye-sight, stronger ability to sense magic, grow to adulthood faster etc), doesn't mean that all of him will be better. In fact you're likely to get a bit of both at times, with a hybrid suffering by not fitting into either parent species niche, but perhaps getting one or two things he is better suited at as well. Sometimes you get a more complicated example. Like the Liger (half lion, half tiger). The Liger is HUGE, much bigger than either species, due to a fluke of genetics. This could make him much better in a fight potentially, but comes at the down side of needing much more food to eat, and being slower, more prone to health issues since his body can't support its own size, and likely worse at actually catching prey etc. All things considered the large size is likely a weakness in many ways, but it does have some benefits as well. Of course the easier it is for a race to interbreed the closer their genetics are, which will mean an example like the Liger is less likely to occur, these sort of extreme difference are more common the more different the parent species are. Darwin's Dilemma - why aren't we all hybrids? Think about it, if two races are living close together you would expect a lot of matings between them, and their children will mate, etc etc. After a while you get a whole bunch of hybrids of various degree, to the point where a 'pure' race individual is hard to find...wouldn't you? This is actually a real question Darwin himself had: why do species exist at all instead of a random collection of hybrids all along the species hybridization line? The answer is koinophilia. In short, we will instinctually not find other races (again, I'm talking fantasy races, not races on Earth) as attractive. As I said, most hybrids will suffer from outbreeding depression, meaning most of the time if you mate with another race you get a child that will be weaker, struggle, and may not be able to find a mate of its own. Thus over millions of years of evolution we, and all animals, evolved an instinctual tendency to avoid mating with different species to ensure we have strong and healthy offspring. I already have [an answer](https://worldbuilding.stackexchange.com/questions/44374/how-to-keep-species-pure-bred/44410#44410) discussing this, so I won't go into it more. Short version though, remember that mating between races will be a lot less common than fantasy stories generally imply. Also remember this DOES NOT require racism, this can be instinctual and not even recognized tendency. [Answer] In the real world, dogs are all the same species (Canis familiaris) so they are not half-something, and all interbreeding is between different races of the same species, so they are all dogs. But breeding a dog with a wolf (Canis lupus) creates a half-dog, half-wolf, which is a different thing, not a dog anymore. On the opposite hand, horses (Equus ferus, previously known as Equus caballus) and donkeys (Equus asinus) are different species and will always produce infertile offspring. Same for lions and tigers. But they are both Equus, as wolves and dogs are both Canis, and lions and tigers are both Felis. So individuals of different species but belonging to the same Genus may produce infertile (sometimes but very rarely, fertile) offspring. Elephants (Loxodonta for the african or Elephas for the indian) and giraffes (Giraffa), or humans (Homo) and chimpanzees (Pan), are not of the same Genus, so no offspring is possible. Note: not even between asian elephants and african elephants! And then you come to that and add magic... [Answer] Whether "race" has any significant genetic meaning is an ongoing, much-debated question. That said, the question is a good one. My current fantasy world puts this front and center -- but only I know about it directly. In essence, orcs are very close to the primal ancestral fey species, from which elves, dwarves, naiads, pixies, goblins, and whatnot all evolved. Crosses here are fully functional, but tend to "prefer" one parent over the other. Humans, on the other hand, are quite different, and crosses are always sterile. Thus half-elves and half-orcs are always half- something other than human. The thing is, the officially-standard D&D kind of world is the official normative thinking, because dwarves and elves swear themselves blue that they are utterly unrelated to orcs, despite all evidence to the contrary. Everyone seems to think that orcs and goblins are some kind of unfortunate savage monsters who happened to come up (semi-)intelligent, and on the whole the human civilizations have gone along with this line. So what you get is a kind of strong racism that is deeply inculcated in the players (not the PCs, the players): the assumption that orcs and goblins are "monsters" whereas elves and dwarves are "people," when in fact the main difference between orcs and elves or dwarves is what we humans in the 21st century call "race." And the difference between humans and any of these is something much more significant, a genuine speciation difference. I think this is something such fantasy worlds ought to mull over a good deal. You can magically handwave it away, of course, but why not use it? You know it nudges players to quick and deep reactions, so it's powerful. Don't waste that! [Answer] Taking Star Trek as an example most humanoid species seem capable of reproducing however some require medical intervention (it's fair to assume that ST parents don't want infertile children). Taking this concept into a fantasy setting there's no reason why some/all cross species pairings couldn't require the same help. Perhaps an interspecies couple need to seek the help of a High Priest of X or a local hedge wizard to allow them to conceive? Perhaps an apothecary can create a elixir? In my opinion seeking expert help is a very realistic option if you don't want to go down the common ancestry route - after all millions of people in our world seek help and that's without cross species complications! [Answer] If you are dealing with a world of gods and magic then you can create a magical reason. For a world I built it's a plot point that there is a magical item that allows and maintains the ability for to species to breed together and if it's ever broken this can no longer happen and further the half breeds that currently exist will become unstable and tear themselves apart. You can also use the idea of soul shaping. Sould have a form that they manifest in the body so it not the genetics that allows races to mate and produce offspring but the souls of 2 beings coming together to produce a new soul. The "baby"/"body" is just the way that this new soul is using to manifest into the physical world. ]
[Question] [ When creating a map for a fantasy world, I typically add broad top-level descriptions for terrain. Mountains here, forests there, a river, a swamp etc. Watch any nature documentary, and each terrain type in reality has a huge number of variations which radically change what they look like, and what it means to experience them. I don't have time to gain qualifications in geography or encyclopaedic knowledge of all possible rock types, ages of mountains and 100s of factors that in reality contribute to how each part of a world is unique. But I'd like to improve on what I currently do. What is a good way to organise my map-making and thinking to the next level, so that I can qualify the types of mountain, swamp, grassland, tree cover etc? I am looking for something that doesn't overwhelm me with complexity, but that gives me more to work with when mapping and when explaining what it is like to experience the terrain for e.g. game characters when they are in it. Clarification: I want to add the qualities when I am describing a part of the world, so the details do not necessarily have to be on the map (as symbols or colour codes) - but in that case, how can I organise myself so that the data is there for me when I need it? [Answer] ### Define Yourself The easiest way may be to use terms in the language of the people in your world. That way you can define the term to mean anything. (Ex. "Jerlo" means large hills, not quite mountains). The disadvantage of this is that your readers/players never come in with a knowledge of terms. You have to explain every one. Granted, you would probably have to explain any scientific ones too, because most users wouldn't get those either. In either case, there is a decent chance users will forget them, so you might want to have a glossary stored somewhere. ### Research The other way would be to research things, and look for broad types of things. These terms wouldn't be as specific as "all all possible rock types," but they will give your users a easier time of what you're showing. You may still have to define these terms in a glossary. For example, mountains have several different varieties, volcanic mountains, fold mountains, and block mountains (see [this](https://en.wikipedia.org/wiki/Mountain) Wikipedia article). You could use those terms and others to better define your geological resources. A lot of geological terms (many more specific than you want), can be found [here](https://en.wikipedia.org/wiki/Glossary_of_geology), on Wikipedia. For example, the article defines aa "Dike - or dyke - a type of sheet intrusion referring to any geologic body that cuts discordantly across." You can use this as a reference for your map. The basis of general terms for climates are [Biomes](https://en.wikipedia.org/wiki/Biome). Biomes are large areas defined by similar climate. These will have similiar abiotic and biotic features (i.e. similar plants, animals, and climate The important factors for a biome are: * Latitude, list starts with the poles and ends at the equator + Arctic + Boreal + Temperate + Subtropical + Tropical * Humidity, list starts with most humid and ends with least humid + Humid + Semihumid + Semiarid + arid + Humidity can also be defined by rainfall + Seasonal Variation. The rainfall is distributed roughly evenly throughout the seasons. Some places have a dry season and a wet season. Most of the rain falls in the wet season * Elevation. + Increasing elevation distributes climates similar to how change in latitude distributes climates. Biomes are also fundamentally divide into two classifications: Terrestrial (land), and Aquatic Biomes. You can use the above words to classify biomes even if you can't find official names for them. There are several different official ways to classify Biomes, many of them are listed on [Wikipedia](https://en.wikipedia.org/wiki/Biome#Biome_classification_schemes). Here is a possibly helpful graphic (from the Wikipedia article), that shows the Biomes on earth. It may help you in making your map. ![enter image description here](https://i.stack.imgur.com/Gp2RL.png) Note: The legend is linked, if you want to click the links please vist the [original article](https://en.wikipedia.org/wiki/Biome#Map_of_biomes). [Answer] If I'm understanding your question correctly, the concept you're looking for is probably a [Biome](https://en.wikipedia.org/wiki/Biome) or something similar. > > Biomes are defined by factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest, woodland, savanna), and climate. > > > Effectively, you're looking for "What makes this forest different from all other forests?", and the answer is "In this region, all the forests are similar. But over here..." There's a good graphic in that article which shows how variations in temperature and precipitation create different environments: ![Biome chart](https://i.stack.imgur.com/f15Qi.jpg) You'll need to look up each of those terms to see what is meant by them, but it's a good way to break up your forests. For example, the ["Woodland/shrubland"](https://en.wikipedia.org/wiki/Woodland) area might count as a forest for map purposes, but it's going to be relatively light and airy, with thin trees spaced further apart, compared to a ["Temperate seasonal forest](https://en.wikipedia.org/wiki/Temperate_broadleaf_and_mixed_forest) which will have taller, bigger trees, and be much darker. Poking around on Wikipedia starting from the Biome article should introduce you to all the other variations, or you could check out [this list with descriptions](http://www.factmonster.com/ipka/A0769052.html) or [this site](http://www.ucmp.berkeley.edu/glossary/gloss5/biome/) which goes into a lot of the details of each area, including typical flora and fauna. [Answer] # Let your needs lead your learning If you want to create a thoroughly realistic mixed map with lots of different terrain and plant cover types, then you need to do a lot of research, not just on the terrain types but on how they interact both long and short term. However, if your map contains things for a reason, then you can focus on those reasons rather than building an entire world from scratch. This way you just learn what you need and cut the amount of research you need to do. If you have a story or a game that requires that certain regions be difficult to reach or travel through, or that certain creatures or monsters are restricted to certain areas of the map, for example, then you can draw your map in terms of such requirements, and then use that to drive what types of terrain and plant life are needed. Then once you know what is needed at an abstract level, you can look up specific types to see which best fits what you need. For example, if you find that you definitely need two types of mountain, one that is impassable and one that slows travel, then you can research mountains with those characteristics, rather than read everything on all types of mountain. Similarly if you need a terrain that will prevent migration of lions, you can research lions specifically, rather than researching all terrain types to search for one that might fit. This won't help if you want to create a truly lifelike map based on simulating tectonic movements over geological time, but if you just want a reasonably believable map that provides for a particular story, this should allow you to learn a great deal of detail about only a few things, giving you much more time to do so. [Answer] Wikipedia articles can lead you on to new fine-grained classifications. At the bottom of the [Biome](http://en.wikipedia.org/wiki/Biome) article you find a list of biomes like tundra, swamp etc. Going to the bottom of the [Grassland](http://en.wikipedia.org/wiki/Grassland) article I scroll down to the bottom and quickly find tables with words like savanna, pampas, steppe and prairie. To the reader, words like "prairie" and "steppe" hopefully bring up more vivid pictures than "grassland", so just drilling down to synonymes via wikipedia may enrich your map. True a [thesaurus lookup for grassland](http://www.thesaurus.com/browse/grassland) bring up many of the same synonyms, but on wikipedia, more information on the habitat is only a click away, so that the fictional land can be quickly populated with suitable plants and animals. ]
[Question] [ Let's say for some odd reason, a planet (while in orbit of something) travels at all times inside of a nebula. What all would happen to the planet? Could it sustain life (if sunlight was substituted), or would the nebula cause some other nasty side effects? [Answer] Like Samuel mentioned in a comment, the effects would be minor to slim at most, and probably not detectable except from a significant distance. [Nebulae](https://en.wikipedia.org/wiki/Nebula) are extremely sparse. Wikipedia states that > > most nebulae are far less dense than any vacuum created in an Earthen environment - a nebular cloud the size of the Earth would weigh only a few kilograms. > > > This can be compared to the Earth's mass of nearly 6×1024 kg. If we take "a few kilograms" to be approximately equal to "6 kg", then a nebula is 10-24 times as dense as the Earth. While the numbers aren't directly comparable because of the difference in size, for comparison, the Earth weighs 3×10-6 times as much as the sun. We can also compare a [planetary nebula](https://en.wikipedia.org/wiki/Planetary_nebula#Physical_characteristics)'s 102 to 104 particles per cm3 to Earth's atmosphere's some 1016/cm3. This is more than in the interstellar vacuum, but still a better vacuum than we can manage to create here on Earth with current technology (which is, at best, [some 103/cm3](https://en.wikipedia.org/wiki/Vacuum)). I find the probability that such a sparse gas cloud would have any real measurable effect on the planet itself to be very small, although over extreme periods of time it might cause the planet's orbit around the sun to degrade ever so slightly. I would consider it more likely that the planet would just clear its path around the central star, similar to how some of [Saturn's moons clear their path through Saturn's rings](https://en.wikipedia.org/wiki/Rings_of_Saturn#A_Ring). The probability that said gas cloud would have any effect at ground level on a planet that would otherwise be able to sustain life (sufficient gravity, atmosphere, etc.), even if said planet was in the middle of the nebula, seems even smaller. The probability of any of the gas making it to the surface of a planet seems even smaller than that. If all gas in the Earth-sized nebula described by Wikipedia was added to the Earth's atmosphere, it would result in a concentration of about 10-17, or about 10 parts per billion billion. The stuff would have to be pretty seriously nasty for that to even be detectable. Even [TV Tropes has an analysis page on the subject, stating that](http://tvtropes.org/pmwiki/pmwiki.php/Analysis/SpaceClouds): > > If you found yourself suspended in the midst of a nebula, you likely would never know. That is to say, if you flew your rocket ship up to, say, the Orion Nebula, it would pretty much look like nothing was there. /.../ The reason that interstellar clouds appear opaque and dense is because they are very, very, very, very far away and very, very, very, very large, and this perspective makes the clouds appear compressed and thus solid. > > > This interstellar particle density might plausibly make things very slightly interesting for your FTL-drive-equipped space-faring civilization, but that's probably about it. What you should keep in mind is that nebulae are normally formed as [a byproduct of stars growing old](https://en.wikipedia.org/wiki/Nebula#Formation) and shedding some of their mass. The probability of any planet orbiting the star that formed the nebula to support life seems miniscule at the very most, although with large nebulae, it is certainly possible that the nebula extends into other planetary systems which are able to sustain life on one or more planets orbiting the central star. So go ahead and place your planet in the middle of a nebula if you want to, but don't expect the nebula to do anything too fancy to the planet or its inhabitants. If you want it to be realistic, make sure to place the star system in a region of space with a mixture of old and young stars within a radius of, say, 50 light years. [Answer] The effect of the solar wind would probably create a clear, expanding, bubble in the nebula. So, as thin as the nebula is, there shouldn't be any effect within the stellar system. Getting to that system might be interesting, depending on your FTL tech. [Answer] It depends on the density and composition, generally the first figure is so low that the composition doesn't matter at all, stellar wind also breaks up nebulae so a planetary system will usually be safe from any particles in the cloud. The only scenario I can think of in which there might be any problems would be if the planet's star system was travelling so fast that the primary didn't push the materia of an unusually high density nebula out of the orbital path of the planet and that nebula was primarily composed of something like [FOOF](https://en.wikipedia.org/wiki/Dioxygen_difluoride) or other extremely reactive compounds that will create a rising concentration of toxic and reactive compounds in turn. ]
[Question] [ I am building a habitable Earth like planet, but instead of it being in a solar system it is inside a Nebula. The actual composition of the Nebula is uncertain at this point. I am thinking the planet still needs one or more stars (that are also in a nebula) to provide it with light and energy. I am curious about the many possibilities this could give me: * What would the sky on such a planet look like? I am guessing that the nebula would be clearly visible during night time, but would it still be visible during the day? Would the blue sky block out the nebula in a similar way that it blocks out the stars? [Answer] The January 2003 issue of Astronomy had an article "Under Alien Skies" that investigated what the sky would look like from the surface of planets in multiple locations, including inside a nebular. There is a making-of article here: <http://www.badastronomy.com/media/inprint/underalienskies.html> It starts with the bad (boring) news: > > I immediately ran into a problem. Although the nebula is bright enough to be seen by the unaided eye even from 1500 light years away, I quickly realized that from up close it would be invisible! This shocked me, but I knew I was right. The problem is that the gas is almost transparent, what astronomers call "optically thin". It glows because it is energized by the flood of ultraviolet light from the Trapezium stars.But since the nebula is transparent, we see light from every atom of it all at the same time; the light from atoms on the far side of the nebula comes right through the gas. That means that the light we see is all the light there is from the nebula. > > > But then gets to the good news: > > "The light from the thin gas would get spread out, but there are narrow shocked filaments all through the nebula. Those are small, and they'd still be bright.". > > > "So, " I replied, "the sky would be filled with a web of ghostly green tendrils?" He nodded. "Yep." > > > And the interesting news: > > Then, disaster. Jeff Hester called back... and said everything I wrote about the Orion Nebula was wrong. Gulp! He said it would be accurate for a nebula that is just rarified gas, but the Orion Nebula is far more than that. It's actually part of a much larger thick molecular cloud. This cold cloud of gas and dust is completely opaque to visible light. The Trapezium stars formed in it, and they are so hot that soon after they switched on, their heat and UV light started carving a cavity in the cloud. They were near the edge of the cloud, and eventually ate their way out to the edge. The cloud blows out from there, allowing us to see in. > > > But those stars also illuminate the thick gas in the molecular cloud. Since this gas is thick, from up close it would still be bright! > > > The original article had images to accompany it, although they don't seem to be easily found online. [Answer] The reason we don't see stars during the day is not because the Sun is too bright, but because the blue light in sunlight is scattered by [Rayleigh Scattering](https://en.wikipedia.org/wiki/Rayleigh_scattering). This means that it appears to come from all directions at once. If this effect wasn't present then only the sky immediately adjacent to the sun would be bright and the rest of the sky would be dark enough to see the stars. So, if you assume that your planet's atmosphere has the same properties as Earth's then unless your nebula were bright (as bright as the Moon, which is visible during the day) I don't think you would see it. Having said that, you can see Mars, Jupiter and Venus at dawn and dusk when there is still some sunlight to scatter. So, you'd see more the nebula if there was less/no scattering of the sunlight or if the nebula were about as bright or brighter than the Moon. ]
[Question] [ This Query is part of the Worldbuilding [Resources Article](https://worldbuilding.stackexchange.com/questions/143606/a-list-of-worldbuilding-resources). --- Once geological processes have created a landscape a number of factors come into play in order to reshape it. This includes weather and climate effects such as wind, rain and ice reshaping the terrain. * What are the processes that reshape land-masses and alter the terrain after it has initially formed by geological processes? * How can those processes be easily drawn upon to create realistic looking maps? --- Note: > > This is part of a series of questions that tries to break down the process of creating a world from initial creation of the landmass through to erosion, weather patterns, biomes and every other related topics. Please restrict answers to this specific topic rather than branching on into other areas as other subjects will be covered by other questions. > > > These questions all assume an earth-like spherical world in orbit in the habitable band. > > > --- See the other questions in this series here : <http://meta.worldbuilding.stackexchange.com/questions/2594/creating-a-realistic-world-series> [Answer] If you've decided to go with Plate tectonics, the biggest thing to remember is the world is ever changing...you are simply producing a snap shot of a particular point in that change. Geological processes, although still completely active, can be neglected as they operate on a scale far outside of our own time frames. Ice vs water, hot vs cold. The sun has cycles...many of them with time frames much beyond our lifetimes, so they are much harder to observe. That said, there was likely a time where the mass of land that is currently Greenland was warm and tropical. Reversely, there is the 'snowball earth' case where the globe quite literally froze down to snowball with a thin strip of open water at the equator. This rotation between snow and ice will be your biggest global erosion. First, you will have 'major' erosion effects...apply these to your world first: 1. Glaciers are amazingly heavy...this weight quite likely melts water near the bottom of the glacier that's in contact with the land, so you get the equivalent of a giant scrub brush up against the land with a few million tons of pressure pushing it along. This produces a layer of soft sedimentary rock that can actually be amazingly thick. This process also works as a 'reset' mechanism...whatever land formations and features existed prior to be covered by a glacier likely don't exist any more. Remember glaciers 'flow' and the ice that's at the very end of a glaciers reach once started out at the top of the glacier. Additionally...glaciers have the interesting ability to carry rocks (large boulders) on it's surface. When they finally do melt, these boulders can be left in the strangest of spots, a giant flat plain with an amazingly large boulder sitting on it (easiest answer for an unexplained rocks = glacier put it there). 2. water flow. Once again, always in change. There are several theories that have, without our intervention, the Mississippi river changing it's route to the ocean about once every 1500 years. The rivers you place may not have been there very long and may be changing which way they flow in the future. 2a. Pick your continental divide. Water on one side of this divide will flow one direction towards the ocean (ocean being the 'low point', lakes can always be side destinations) while water on the other side will flow to the other ocean. Gives a good starting point for rivers. Most large scale continental rivers will find their beginnings high in the mountains as glaciers feed tributaries that eventually become the massive flow of a river. Remember water always flows downhill, but it won't always be the most direct route since other obstacles may exist. Steeper declines tend to produce straighter rivers (force involved lets them cut through that much more) vs relatively level land that produces meandering rivers wandering slowly around hills (and could easily change direction through their lifetimes). 2b. Plains are formed by ice, grinding the rocks to dirt and sand, and leaving it hard and flat packed. Overtime rivers cut into this flat land and create the river ways...with enough time, these river ways cut deep into the relatively soft earth left behind in a glaciers path eventually leaving behind features such as the grand canyon. Clay also plays a role here...high amounts of clay in the soil tend not to erode as quickly (not water soluble), which greatly inhibits a rivers ability to cut out features such as canyons. 2c. large scale events. If we had a glacier existing to the size of north america before it begins to melt...it would start off it's melting process as creating small lakes on the surface of the glacier. As the ice continues to melt, these lakes merge with each other and eventually become a considerable water mass held up by quickly melting ice. When this breaks, the entire contents of a lake that's potentially larger than several midwest states combined spills out in one giant event. If it releases into the ocean, this can cause an immediate rise in ocean levels. This is theory...but it's thought people (homo sapiens in the time of coexistence with Neanderthals) once lived in whats now the black sea. One of these glacial lakes dumping into the Hudson bay caused a global sea level rise that initiated the flooding of that former human territory and ended up creating the black sea. Alternatively, the entire mass of water can be dumped onto land and allowed to flow south...there is an event in North America where all species over a certain size went extinct and a good portion of smaller ones as well (it's the reason why the North American elephant no longer exists). Running theory is a glacial lake was dumped out across North America and created much of the great plains that we know (a mass water dump like this creates hills and plains formations) 3. Vegetation. Life is actually the counter of erosion...life fights to retain stability in an ever changing world after all. Trees and plant matter tirelessly work to keep their soil..well, theirs. Root systems give dirt the stability it needs not to be washed away in a simple rainfall. One of the scary examples of this (I'd have to go digging for pics), is the island nation of Haiti. It went through some heavy sanctions that ultimately cut them off from Oil. The response was for the population to use the trees and in a very short time, the island of Haiti underwent 98 - 99% deforestation. If you can find it somewhere, get a pic of Haiti from google earth prior to 2004, and then find a more recent one. Since the deforestation, the river delta's have rapidly grown as, without the forestation to protect it's soil, the island has literally melted. General rule - the more the plant life (forests especially), the less the of an effect the erosion forces of water will have. Most other effects (such as wind and tide) tend to have more localized effects, where they definitely leave their mark, however they do not do it on a mapping scale. Want the 'non-plate tectonic' version of this? Earth does a great job in redistributing energy, which ultimately comes with more movement and more erosion. Mars/Venus would be less dependent on this and volcanic activity would become a partial driver. [Answer] 1- Glaciations: This phenomenon appears in regions close to the poles. The last glaciations covered North America but also Northern Europe and Asia. On an earth-like planet, places far from the poles are not affected unless the temperatures drop to a very low point. Our planet had several ice ages in the past. This creates a movement of the ice sheets. They move south when the temperature gets colder. When they melt, they start moving again. All the movements cause erosion and can move a large amount of land with it. The fjords in Norway are a good example of this process. When they melt, sometimes the water can reach the ocean, but not always. The natural geography of the land, but also the weight and movement of the ice can lead to the creation of lakes when the ice is melting. That is why Canada and Finland have so many lakes. 2- Water flow: It is important to know that water is always flowing downhill and always use the shortest route available to reach the sea, or the closest large water body. The shortest route depends on the surrounding landscape, an obstacle can prevent water from flowing in a particular direction, such as a higher elevation. Rivers rarely splits and if they do, it's generally on small rivers and it's only temporary. The erosion process will be uneven and eventually, there will be only one river. More about river bifurcation can be found here: [How (un)likely is a split of one major river into two others?](https://worldbuilding.stackexchange.com/questions/152/how-unlikely-is-a-split-of-one-major-river-into-two-others/153#153) The exception for this is the delta. Deltas are form with the accumulation of sediments carried by the river (dirt, sand, organic sediments). The formation of the delta can be temporary or permanent depending on the origins of the sediments. Lastly, the flow of water erodes the landscape. Younger rivers tend to be straight with smoother banks. Older rivers are more sinuous and can have steep banks due to erosion. Some river, old enough can create deep valleys. On lakes: lakes tend to have only one output river (if any). Since water always take the shortest route, you are unlikely to have to have two places at the same dept. 3- The freeze/unfreeze cycle can also create interesting formation such as the pingo. The water into the ground changes the shape of the land at each cycle : <http://en.wikipedia.org/wiki/Pingo> But they are usually too small to be represented in most maps. \These are the factors I know but there could be others. [Answer] The literature can use different names for the same erosion. It also tends to have a seperate name for processes that can be easily grouped. As a result this is a distilled summary of major erosion processes. What are the processes that reshape land-masses and alter the terrain after it has initially formed by geological processes?* 1. Aeolian Erosion * Saltation causes erosion at lower heights to be greater when the wind blows softly, creating pedestal rocks. * Freely blown particles erode at all levels. 2. Thermal Erosion * Thermal expansion of heated salt crystals and cooled water causes pressure inside the cracks and pores they collect in, resulting in scree and tafoni. * Thermal gradients from sunlight, fire, or any other source of heat. Pressure is built up from inhomogenous materials and/or sharp temperature change in a material. When the pressure gets high enough you get wear on the material. One result is surface exfoliation. 3. Hydraulic Erosion * Precipitation erodes the surface layer and takes the path of steepest descent with a basin. Basin may have sub-basins in a hierarchy. * Tidal erosion causes coastlines to degrade into silt and sand, and carves cliffs in taller and sturdier materials. * Healthier soil holds more water and contributes to higher levels of rain in the surrounding areas * Rivers have a water source (typically percipitation), and they erode differently depending on gradient and volume of the water. Larger volume results in slightly larger objects being moved but mostly increases rate of erosion. Larger gradients increase size of objects moved. Rivers form V-shaped valleys over time. * Flooding redistributes erosion and tends to flatten areas. 4. Glaciation * Forming in cold conditions, they scoop out U-shaped valleys. Carries loose rocks like a conveyor belt. And grinds down the rocks it sits ontop of. 5. Biologic Erosion * Bacteria, plants, and animals modify the soil structure throughout their lifecycle. This changes erosion characteristics by increasing chemically reactions and water retention. * Different plants affect their region differently, mangroves reduce tidal erosion. Grass reduces wind and water erosion, and so on. Plants with shallow roots stabilize against surface erosion and plants with deeper roots anchor steeper slopes against landslides. They can also mechanically weather the soil by growing into cracks and pores to break rock apart. * Mechanical erosion from creatures moving can form trails that will even wear down materials harder than themselves such as stone (now look at your keyboard). 6. Chemical Erosion * Hydrolysis wears down rocks such as limestone where it creates limestone caverns. The reaction is driven faster in the presence of carbonic acid from acid rain. The effected rocks are carbonates and silicates which tend to get dissolved, and aluminosilicates which produce a secondary, usually weaker, material. * Hydration of rocks increase pressures in the material resulting in increased pressure erosion. * Oxidation can physically weaken the surface layer of a material, making it brittle and allowing erosion to happen more easily. Pressure Erosion * Pressure release in the material (usually from removal of surface layers) causes inclusions to expand and fracture the surrounding material. How can those processes be easily drawn upon to create realistic looking maps? From a bare tectonic map you have rock-type information. You also have basic heating information and major wind currents that can be modeled based off the bare tectonic map. Precipitation can be modeled to get base moisture levels. Basins are already present at this point in the geologic structures, you can use a gaussian blur to extract a scale-space representation of the basins and sub-basins that you can use for segmenting if you don't already have that information. You can use the preceding information to develop the information for soil types and biologic population. These will effect soil quantity and fertility, which will decrease erosion in general, increased precipitation and moisture levels, as well as increase erosion on selected soil types in the presence of certain species (trees will break down craggy rock quicker). Higher populations will reduce the anti-erosion effect of plants and increase mechanical wear. ]
[Question] [ So, I have a superhero, and his name is Logan Wotowski, the indestructible man. He can survive and heal from gunshots to the head, knives to throat, getting hit by cars, fire, electrocutions, high falls, disembowlment and explosions, you name it. No normal, ordinary injury can kill him. So, in my story there is a scene in which he is trying to disarm a bomb and he can’t leave since he’s trapped underground in a coffin. While he’s trying to disarm the bomb, he’s terrified as all get out. All the other times he’s about to die, he’s afraid too. My question is, why would an invincible character still fear mortal injuries? [Answer] Logan might have a supernatural healing factor, but not superhuman pain tolerance. Having suffered the horrible pain caused by injuries no other human ever survived could have been a traumatizing experience he really, really doesn't want to repeat. Most people assume that getting blown to pieces by a bomb is a quick and painless death. But Logan knows that he will feel how every part of his body gets ripped apart, and that he will survive with the memory of it. And that expectation terrifies him. [Answer] The possibility of being buried alive is a very powerful fear. The Old Croghan Man was a mummified body found in a bog estimated to be about 2000 years old dug up in Ireland. Imagine that body was your super hero but alive for all of the 2000 years. What he fears is his enemy finding him during his defenseless regen phases and moving him somewhere encased in concrete, and then construction workers simply building a new building above him. We are probably never going to check what is buried 10 feet underneath the bottommost stone of the pyramids of Giza. Even if the hero knows a nationwide manhunt will follow if he goes missing. Remember [MA flight 370](https://en.wikipedia.org/wiki/Malaysia_Airlines_Flight_370), they searched about 4,500,000 km² of ocean floor for its transponder, which is about half the area of the USA. Now good luck finding a box with a built-in radio signal. Imagine waiting in a coffin of concrete and rebar until the deep ocean wildlife has effected your environment so you can even begin trying to dig yourself from the ocean floor. [Answer] ## He doesn't trust in the healing factor * He has never been decapitated nor lost his head (literally). He isn't sure if his healing factor is able to heal the whole loss of the brain: maybe it's possible, but maybe the new brain loses all its memories. * He doesn't know how his healing power works: maybe it has a limited amount of uses like [@david starkey](https://worldbuilding.stackexchange.com/users/16958/david-starkey) suggested. Who knows, maybe his special stem cells aren't able to replicate themselves, and each time they heal something, they die in the process. And obviously, he doesn't want to take the risk and try it. ## He is still a human Humans have instinct, things that they can't control completely. Some people are afraid of heights, even when they know they won't fall. He is still a human, a super-human but after all a human. He can't control that kind of instinct. ## He suffers pain Again, he is human and humans are able to suffer pain from injuries. Furthermore, humans have a pain tolerance, and reaching that threshold can have some psychological consequences. For example in [Tokio Ghoul](http://tokyoghoul.wikia.com/wiki/Ken_Kaneki) spoiler: > > Ken Kaneki has a hyper-fast healing factor, which heals so quickly that when he was captured and tortured, his torturer used to cut off his fingers and toes every 10 seconds, for 10 consecutive days. Ken Kaneki get a bit traumatized... his hair became white, his introverted and friendly personality disappeared and until he lost his memory (and got a second personality) he used to cut the fingers off everyone he met, and then eat their corpses. > > > [Answer] In Larry Niven and Jerry Pournelle book Inferno, the protagonist is in Hell and can't die no matter how badly he is hurt. Even after he's gotten so shell shocked he accepts that he will suffer pain, he avoids it when possible because it hurts so much. He may have to wade through a lake of boiling blood but he'll stay in the shallows as much as possible so only his legs cook, jumping down a jagged cliff is preferable to being torn apart by demons, etc. Since he can't die his nerves never deteriorate, the pain never numbs, it's always sharp and fresh. Now imagine feeling all of that as your body tries to knit itself together? To die of oxygen deprivation and come back to life every few minutes only to die again, and again, and again. And except for the times when death mercifully knocks him out for a few seconds or minutes, his brain is active enough to sense the pain, the death throes of his body, the raw nerves regenerating before the muscles and skin. I'd be terrified of being hurt that badly, at least death would end the suffering, his will never end. [Answer] Is it possible that his healing factor hurts others? For instance, maybe when he heals he (involuntarily) takes someone else's lifeforce. Near-death experiences for him are real-death experiences for someone else. He's terrified that someone else will suffer or die as he heals. [Answer] He is a total wuss. Yes, he is afraid of getting hurt. Also afraid of spiders, and daschhunds, and that there might be a raisin in his bread (he always checks because ONCE THERE WAS!). He is afraid that his underwear might be on backwards and he will have to walk around that way until he can get to a restroom and switch them back. He is afraid of riding on the bus and afraid of those rotating doors in big hotels and department stores. Also he is afraid he might have an ulcer (he might) and that the pharmacy gave him someone else's medicine and that his sandwich wasn't really beef but it was horse and he liked it! It is bad enough that he is afraid of all this stuff but worse is that he will let you know he is afraid, over and over, in a whiny voice, and it is all your fault. It is pretty amazing that he ever does anything heroic. Although you do not stipulate that he ever actually does. [Answer] Because, in line with [this question](https://worldbuilding.stackexchange.com/questions/118827/what-mechanism-can-prevent-super-healing-heroes-from-accidentally-budding), there are already seventeen of him and it's starting to get silly. Yeah sure he can be in several places at once, but the bed is getting crowded. He regenerates, but he has no way to know which part of him to regenerate from, so unless all detached parts are back in contact within a few seconds he regenerates from all of them. This is fine when he's lost an arm, he can grab it quickly, but being cleft in twain is a bit of a problem. The problem first showed when he was caught in a decapitating trap, his body couldn't find his head so it grew a new one, his head couldn't see his body so also grew a new one. It went rapidly downhill from there and now his favourite point to stand overlooking the city and brood is always occupied by another one of himself and they all claim to be the original. Getting blown to smithereens would cause no end of trouble, there could be hundreds or thousands of him running around. [Answer] Regeneration is fine and dandy for most things, lose an arm, grow a new one. It might hurt, but he'll be okay in a few days/weeks/months. But if he suffers head-trauma, or gets his brain blown out, he loses memories. Having his brain destroyed by a bomb means that he's going to grow back a new brain, perhaps with some of his memories, perhaps not, but it's going to be a serious long-term effect either way. Realistically, he should be more or less a newborn baby neurologically, but handwaved by supernatural abilities, perhaps he will be "backed up" to the last time he slept, or to the day he acquired his powers. Imagine waking up in screaming pain, under meters of soil with no idea how you got there and the last thing you remember is either going to bed or suffering a traumatic super-power activating experience. That's enough to give me the heebie-jeebies myself! [Answer] Are taking a bullet to the head and being blown to strawberry jam both healable? One of the many reasons for beheading is that you're absolutely sure the dude is dead. If I behead Mr. Wotowski, is he dead? Or can his superpower replace a head complete with brain? The answer should be "no." Therefore, it is possible to do so much damage that the superpower cannot repair it. Being blown to bits qualifies, and therefore justifies Mr. Wotowski's substantial fear of death. If being blown to bits is healable by the superpower, then he isn't superhuman, he's a god and entirely indestructable. No fear is justified save for irrationality, which is hard to believe in a godlike being. I'm not a fan of godlike superheros, they tend to be boring. [Answer] I have normal human healing powers. I can survive and heal (and in fact I already have) from several cases of broken bones, burns, cuts and other bodily damage. And yet, for instance, I'm still afraid of breaking one of my bones - even the ones that quite clearly won't lead to death or long lasting damage. I'm not even a fan of cutting my skin when chopping onions, although I would hardly die as a consequence of that. [Answer] Quoting the great Arnold: ["I suppose nothing hurts you." "Only pain"](https://www.youtube.com/watch?v=o79lPZe6ZD4). Your hero seems to be immortal but he is not immune to pain. So, when he is desembowled he will feel it. How bad he will feel it depends on he going into shock and staying unconscious. Another important question is what heals first, the main, core parts of the organism, or the peripherical parts? For example, the villain stabs our hero in the back with a chainsaw. The spine, his guts, like the intestines are destroyed. Then our sadistic villain melts our hero's legs' skin with acid. What will heal first? The main systems like the spine, the arteries and big veins? Or peripherical systems like the shredded bowel's linement and the corroded leg skin? If our hero heals the core first he is for a hell of pain. If he heals the core last, if the last step is the reconnection of the spine, he will suffer less pain. So, the first reason he is afraid is that he is afraid of pain, not of death. A second reason depends upon on how he acquired this immortality: was he a normal human that became a superhealing immortal? Or was he born that way? If it is the first alternative, he is afraid because he still thinks as a normal human, because of reflexes and conditioning. [Answer] In the vein of [Ender Cooks's answer](https://worldbuilding.stackexchange.com/a/118828/53262) about not trusting his power, if he doesn't understand his power he might be afraid that it could stop working some day. Or maybe he has some partial understanding that makes him afraid. If he's always hungry after healing maybe he worries that he won't be able to heal this time if he didn't eat enough for breakfast. [Answer] Well, a few reasons: * It hurts. Obviously. * You can still suffer from things like claustrophobia (being buried alive). * The time he is wounded he can't fight as good as he could in normal conditions. Therefore he can't protect the things he loves as good as he wants (I stole that one from Deadpool). [Answer] One thing you have to be careful about with super-powers is that your character is still vulnerable somehow/has his limits. Maybe he is used to the pain. But there are other weaknesses and potential drawbacks. What is the consequence for constantly being extremely injured? Does healing take a lot of time or energy? Maybe being blown up would take him 5 days to heal, and there's stuff he can't wait 5 days to do. Maybe he is extremely claustrophobic. The coffin is terrifying him psychologically. Maybe every time he gets blown to bits it takes more and more (time/energy) to become whole again. I personally really liked the idea by Ruadhan2300 where he would lose some memories because of the brain damage. Superheroes are fun. But a hero with unlimited powers and no weaknesses or drawbacks can be incredibly boring. Write limits to your character's powers (whether actual--(like how Claire in Heroes (who had a similar power) would not be able to regenerate while a certain part of her brain was stabbed/pierced) or percieved--(MC is scared that he will encounter something he won't be able to recover from.) Either way, limitless power is usually an unrealistic and boring quality. If the MC is in danger, the audience needs to be concerned that they might not make it out of this okay, or they won't be interested. [Answer] Perhaps it's not the immediate physical injuries he's worried about. He's buried underground in an enclosed space. It's possible for your hero to break their way out of a coffin and dig themselves back to the surface ([Mythbusters](https://mythresults.com/coffin-punch) might disagree, but they didn't test with a superhero). What happens if that bomb goes off? The explosion will blow the coffin apart and disrupt the dirt around it. There's no longer anything holding back the freshly-dug and still-loose soil above the coffin. All that dirt will cascade down, filling the space around the hero. The hero may heal from his injuries, but now he's completely trapped under a massive amount of dirt without even an inch of space to move. He no longer has any way to free himself from this prison. He's now faced with the a brand new series of dangers: * If his healing abilities won't work when the pieces of his post-explosion body are thoroughly mixed in with a mountain of dirt, then he may not heal at all. * If he can successfully heal but is vulnerable to suffocation, he'd die within minutes. * If breathing isn't a problem, he faces a slow death by dehydration/hunger. * Even if he's completely immortal, he has to deal with the psychological torture of being completely trapped, helpless, and alone until someone finds him. It doesn't take long in this state for someone to completely lose their mind. Alternatively, your hero could fear the ultimate vulnerability that plagued even the mighty Superman: the inability to be in two places at the same time. Sure, your hero might heal from the injury, but how long will that take? What Awful Things is the villain going to do to his friends in that time? The hero is the only one that can prevent Awful Things, and the only way he can do that is if he stays in one piece. [Answer] ## Vanity Mr. Wotowski is actually really obsessed with his personal appearance. Bomb blasts might not kill him, but they'll certainly ruin his perfect outfit. He can heal easily from shrapnel cuts, but it might result in scars that mar his complexion. If his hair gets burnt it'll take weeks to regrow. At least ordinary baddies have the decency to go down easily, and stick to means that (usually) don't attack his vanity Maybe he was born with superpowers, maybe it's Maybelline. [Answer] Terrible consquences to recovering from mortal injuries. Perhaps Logan has terrible nightmares after recovering from a mortal injury, getting worse every time he revives? Maybe some otherworldly, metaphysical creature creeps up on him, closer and closer? Or perhaps a random person's life is extinguished every time Logan dies and recovers? The superpower is supernatural, so it might have supernatural consequences as well. [Answer] The film "Death becomes her" is a film where 2 immortal women start fighting. While it might seem that there can be no winner and no loser - as they are, after all, immortal, this means only that they do not die. However, injuries sustained do not magically heal - infact their ability to heal is almost completely removed. This means that should they break their neck, they will forever have a broken neck, unable to maintain their heads usual position up on their shoulders, it will fall down from the lack of support. It becomes a fate worse than death; as whatever injury they suffer, however abnormal it will make them; they will not die. Given those conditions, I'd avoid these situations like the plague. [Answer] Religious Reasons Perhaps our hero is religious. He's suspicious of his powers being unnatural at the best of times, but when he suffers what should have been a fatal injury he becomes even more disturbed. Perhaps he believes that he loses a piece of his soul every time he comes back from death (and perhaps he's right). Tattoos More a fear of mutilation than death itself, but I thought I'd throw this idea out there anyhow. He has tattoos, but if he loses the part of himself that the tattoo is on he loses the tattoo as well. Maybe one or more have sentimental value to him that are irreplaceable, such as a loved one's name/image or art done by a close friend who has passed away. Tying in to Ruadhan2300's answer concerning the loss of memory and taking a page from the movie Memento, perhaps some of the tattoos are there to help him keep track of his history. When both the memory and the tattoo are gone, that history is lost forever. Maybe he just really loves those tattoos and is afraid he's going to have get them all redone. [Answer] ## Because his regeneration factor will make him grow limbs in weird places. And he knows it. Usually when it's just a cut or a scratch, it's easy for him to control his regeneration: disinfect, add a bandage, and that's fine! But if he's really badly injured or, like in your scenario, exploded, his regenerative powers could go nuts and he will reassemble in the worst, yet optimal way given the circumstances. ## Or... Let's say you're hurt, you lose a finger and do not sanitize / cauterize the wound. Given time (and some bad genetics) you're prone to catch an infection, or in the worst cases, gangrene that will rot you from the inside. And with regenerative powers gone wild, your hero could grow infected limbs from scratch. Anyway, both options he'd prefer to avoid at all costs. [Answer] ## Instincts of self-preservation Fear is not a reasonable thing. You fear something because you feel so, not because you think it is reasonable. He is a healing factor superhero, but he is also a human being. A human mind has a few basic instincts, including instincts of self-preservation. It is the most basic, naturalistic fear of being injured. Even if he can tolerate the pain, he might surrender to fear. [Answer] One way is to introduce something that can override the self-regeneration. Marvel Comics has a sword that cancels healing factors. Superman loses his invulnerability due to kryptonite or red solar radiation. By having an external factor that cancels out the power, you can create the tension. Let’s say your character’s healing factor can be canceled out by Element X. If the bomb goes off, the character will be shredded by shrapnel made of Element X. Alternatively, make the fear not for their own safety, but for that of someone else. Put an innocent person in the coffin with him. Give him a negative consequence for failure or taking too long. I hope my ideas help. [Answer] People that you love and want to save dying or suffering is something that is important to consider in the vase of worry, fear, and anxiety too. Healing doesnt make you forget pain, and make you lose empathy, if anything it ought to make you more empathetic. [Answer] The bomb might have enough energy to completely vaporize him, or turn him into a plasma. His healing power ceases to exist if he no longer has any structure at all -- not even any DNA. A nuclear bomb would be intense enough to do this, if he is close enough to it. [Answer] All animals in this world have some kind of Healing Factor. It's just magnified in case of superheroes. Superheroes have the ability to heal parts of body which cannot be healed eg. growing broken teeth. There are two reasons for him to be afraid: 1. The pain 2. His rate of healing might be slower than the rate at which the bomb releases energy(heat) since it in which case he'll die a very painful death. 3. The prospect of death might bring fear losing loved ones and not looking after them. [Answer] I think fear is a physiological thing more than a physical thing, I am afraid of getting flu shots even though I don't feel any pain in it. ]
[Question] [ Imagine a future where humanity has reached the stars, an exploration party lands on a earth like planet that's liveable (doesn't have to be perfect but life on it is on the range of what most people would consider comfortable, climate is ok, gravity isn't too heavy or light, breathable air, sunlight, etc), the thing is that due to X they found out they are now stuck on the planet and can't leave, my question is what is the reason preventing them to get back to orbit? * I'm looking for natural causes (or at least non-technological, meaning that some natural non-intelligent bacteria/animal/etc on the planet can be the reason, just not something that said alien animal built) * Ideal answer will be something that only prevents people/equipment on the surface of the planet to get back to orbit but will have no other effects + This is also how I'll rank answers, the lower an "impact" the answer has other then stopping orbital launches the better * To be clear this should be something that will affect all ships landing on this planet, not just local to the region the first ship landed on or some issue with the ship and them not having the right spare parts, had it not been for X the ships landing on the planet would have been able to reach orbit as they have been designed to reach orbit from similar planets. [Answer] How about [Thixotropy](https://en.wikipedia.org/wiki/Thixotropy)? This is a phenomenon also encountered on earth and is the cause for quicksand. Perhaps the surface of your planet appears (and mostly is) solid, but liquifies when agitated by a sufficiently strong vibration, for example the engine of a spacecraft. With a spacecraft half (or entirely) drowned in the soil, each attempt at starting the engines causing it to sink further, the crew remains stranded on the planet. [Answer] In a short story by Clifford D. Simak ([You'll Never Go Home Again!](http://www.isfdb.org/cgi-bin/title.cgi?82441), 1951), this is achieved by some sort of microbe that selectively attacks metallic iron, causing it to rust. In a matter of days, the rocket is stranded. Another possibility (quite farfetched, but spectacular) is an unstable moonlet fracturing at just the right moment, locking the planet beneath a post-[Kessler](https://en.wikipedia.org/wiki/Kessler_syndrome) shield. In Iceworld by Hal Clement, people from planet Sarr, from their base on the horribly cold and inhospitable first planet of the star Sol, observe the strange blue-green plains that cover three fifths of the even colder third planet. All the probes trying to land report that the blue plains are essentially flat, but as soon as they touch down, communications cease (a less drastic version of his very first story, 1942's Proof). Something similar happens to the lander from Aes Triplex when landing on Venus in Heinlein's Space Cadet: the Venusian mud appears like solid ground, but is destabilized by the rocket exhaust and swallows the lander (then, the mud infiltrates the still-working gyroscopes and "fries" them, making takeoff impossible). For this to happen on a whole planet, you'd need a very funny planet indeed, as well as no landing radars or probes. Adverse surface conditions: landing is a comparatively brief matter, staying landed and taking off is a much more lengthy endeavour. Anything capable of disrupting the takeoff procedure could make it risky enough as to call it "impossible". Strong enough winds, for example, or the "surface" being a thick algal mat over an oceanic planet. To be able to take off you'd need first to download (splash-landing them) materials and build a suitable stable platform, or have a specially designed "amphibious" starship - something that can take off like a hydroplane, then reach the stratosphere using scramjets and finally enter orbit, rather than taking off in the usual initially-vertical arc. One really contrived possibility: a design trap. Rocket efficiency depends on external pressure. So, first of all we increase gravity and gravitational well depth, and decrease the rocket's power, efficiency and fuel reserves, so that a successful takeoff is just barely possible (in other words, our starships are designed to only ever land on a narrow choice of suitable planets; they're intentionally under-engineered because of, say, economic reasons). Then we assume that the bottom of the atmosphere, where you actually do land, has an unexpectedly high pressure - because it's not the surface at all, but the surface of an atmospheric ocean of heavy gas (the only candidate, sulfur hexafluoride, six times as dense as air, being unfortunately an artificial gas. This could come in handy though: tests did not reveal the trap, because SF6 is definitely not something you run spectrometer checks against). Again, a specially designed starship (essentially one with larger, more powerful rockets) could still easily take off, but our default starships won't. A definitely implausible but scientific-sounding possibility is anomalous atmospheric ionization, that allows a shuttle to glide down using wings and airbrakes, but would prevent it from igniting the [takeoff rockets](https://www.sciencedirect.com/science/article/abs/pii/S0082078465802132) since it would cause the shuttle to be literally smitten down by lightning. And then there's unnatural causes. In several works (Heirs of Empire by David Weber, Crisis on Centaurus by Brad Ferguson, Impossible Return by Chris Clare) there is a planetary defense system that has been damaged or otherwise gone senile, and may have absurd rules of engagement - such as allowing a ship to land, but treating it as hostile when taking off. [Answer] ## Gravity It is generally considered that there exists a limit, after which it becomes nearly impossible to go into stable orbit using rockets because you will never be able to reach escape velocity. If your ship used atmospheric braking and aerodynamics to land on the planet, it would be able to safely land there, but the crew will be unable to leave it ever again. This question has answers detailing this in greater aspect: <https://space.stackexchange.com/questions/14383> To a lesser extent, your rocket can simply be designed for liftoff from planets with weaker gravity, so it on its own would be unable to break free from the gravity on its own. The downside is that it would probably be unable to safely land there too... Another downside to the entire solution is that it would be unrealistic if the people get stranded in this way accidentally - since gravity is one of the most obvious things a planet can have, you cannot miss that detail. [Answer] Your launch-to-orbit rockets don't work properly because their chemical burn is being messed with by an air-born catalyst in the planets atmosphere. I image some spores of the local moss or grass equivalent have chemical properties that happen to be a catalyst for the propellant/oxidizer mixture that you use for your rockets. This causes the rockets either to fizzle and have not enough lifting power or it accelerates the burn out of control making the rockets explode. You can't replace the fuel because there is nothing else that works with your rocket design. (Or the alternatives don't have sufficient lift capacity when used in your existing rockets.) You can't replace the rockets completely as you don't have the technology base and/or production capability to do that. Eventually your colony may be able to build the necessary local infrastructure to design/build new launch-vehicles. But for now everybody is stuck dirt-side. [Answer] # Quarantine: Oh, crap, now we've done it. We should have sent down the robotic probes first. If what we're seeing is true, this virus and those nearly indestructible bacterial spores have already gotten into all the crew and equipment. The virus appears functionally like the Cthellian flu that killed a billion people. THAT plague spread and combined with other viruses, a lethal combination. Thank God no one in the landing party had the virus that would combine with this one to form an interplanetary pandemic. We can't, in good conscience, take off and bring this stuff back to the vulnerable people in orbit. If we did, we could never entirely get rid of viruses inside crewmembers. It's already inserted itself into our DNA. The folks still in orbit have looked at our results and decided to shoot us down if we take off. I guess that settles it. We're here for the long haul. At least it's pretty here. # Flying Jellyfish: A variation on Kessler syndrome, your crew have to parachute down to the planet because it is full of photosynthetic hydrogen-filled jellyfish that clog the atmosphere. The faster you go, the more you hit. This isn't 100% effective at stopping escape, since people might find clearing times, get to high atmosphere levels with balloons, or blow holes in the cloud of organisms to get out. But they might spend years working out the solutions or have a moral objection to ecological devastation or setting off atmospheric blast nuclear weapons just so they can get off the planet. This solution means they assumedly know about the problem in advance and still go to the planet knowing they will be trapped (escape pods?). If you have to blow a hole in the wildlife to go in or out, and someone sabotaged the nuclear weapons or they detonated them and were unexpectedly delayed (wait, John's ALIVE!), they might not have a backup plan for another pass. Anyone know how to refine uranium? # Volcanic eruptions: [Volcanic ash](https://volcanoes.usgs.gov/volcanic_ash/ash_clouds_air_routes_effects_on_aircraft.html#:%7E:text=Volcanic%20ash%20ejected%20into%20the,critical%20navigational%20and%20operational%20instruments.) builds up rapidly in the atmosphere, and the shuttle they use is designed to operate in relatively predictable atmospheres. Ash of this kind can be invisible to the naked eye or appear as ordinary clouds. Active volcanism in many places can fill the entire plant's atmosphere, although there may be some regions where it is less concerning. The stuff rapidly builds up in the atmospheric engines the craft uses to fly in the air. When they inspect the engines on the ground, the engineer informs them that the rotors are already worn down to dangerous levels and the internal parts are coated in glass. The craft can't fly high enough to reach an altitude to safely engage the rockets. [Answer] # Extreme weather Taking off requires a ŒîV budget which increases with latitude. This is why NASA launches from Cape Canaveral rather than Anchorage, and why ESA launches from the Guianas rather than from Europe. Other than that one of the biggest hurdles is weather. Many important launches such as the recent James Webb satellite or anytime Elon Musk tried to launch a recoverable rocket has been haunted by unfavorable winds. So if your planet has permanent bad weather all the way to high latitudes (say, all the way to 45‚Å∞, which is a tad farther north than NY on the northern hemisphere), then launching should be prohibitively expensive. Even more so with the lack of pre-existing infrastructure. By the way, our own Earth has had multiple periods where this was the case. Two long lasting examples are Snowball Earth and possibly the Carnian Pluvial Event. Eras of active global volcanism would also do the trick by filling the air with dust - I remember some volcano went off some years ago and commercial flights were grounded for a few days worldwide. [Answer] Your explorers were chased down on to this planet. [![cavemen in tree](https://i.stack.imgur.com/pR2e2.jpg)](https://i.stack.imgur.com/pR2e2.jpg) [source](https://www.thatmomentin.com/the-discovery-of-love-in-the-caveman-drama-quest-for-fire/) And whatever found them in space and chased them down onto this planet is still out in space, waiting. Unlike the hungry lion (which gave up after 2 days), that thing in space is fine with playing the long game. It knows they are down there. It cannot itself come down to get them, but it can wait for a very long time. [Answer] # Kessler Syndrome ## [Wiki](https://en.wikipedia.org/wiki/Kessler_syndrome) If a planet has many objects in orbit. Adding new object or energy (Asteroid passing by, Space ship landing on the planet or an explosion) to the system can cause a cascade of collisions between objects, breaking them up in to smaller pieces and sending them in new directions. Making space above the planet inaccessible. [Video Explanation](https://www.youtube.com/watch?v=LkeTk-Fi_c8) [Answer] Cost-cutting and/or negligence. A real-world example: LCS-2 USS Independence is an aluminum-hulled ship that operates in salt water. This takes special measures to prevent corrosion, typically a cathodic protection system. The Independence was originally designed with such a system, but it was deleted to reduce construction costs. Within a year of commissioning, Independence was experiencing severe corrosion damage, and ended up in a drydock for repairs the next year. In your case...ammonia is quite corrosive to copper alloys, which are widely used in rocket engines for their relatively high temperature tolerance and very high thermal conductivity. Perhaps the presence of ammonia in the environment wasn't passed on to the engineers or they were never asked to review the environmental hazards, perhaps the anti-corrosion coatings were substandard, or maybe protective post-landing procedures were skipped to save time and costs. Then launch day comes and critical systems are found to be suffering from severe stress corrosion cracking. [Answer] # Love > > Ideal answer will be something that only prevents people/equipment on the surface of the planet to get back to orbit but will have no other effects > > > So far, the majority of answers I have read have addressed the equipment getting off the surface and people would automatically travel with the equipment. I thought we should look at the fundamental reverse of this. There is nothing wrong with the equipment. There is something wrong with the people. From space/probes/scans, everything shows up as a wonderful looking planet. Air is perfectly breathable, gravity is almost a perfect match for Earth, temperature is on par with Earth's pre-industrial revolution. Water is clean and safe to drink. Plenty of flaura and fauna that are pleasing to the eye and seem to all behave in symbiosis rather than the more destructive preditor/prey/parasite releationships we see on Earth i.e. it's a paradise. When people land, they are delighted with what they find. The planet provides everything they need. It's peaceful, it's happy and everyone seems to be getting on really well with each other. So much better than when it seemed like they were all squabbling all the time whilst cooped up on a tiny spaceship. What was never noticed until people got here is that there is a fascinating reaction between pollen in the air, the minerals in the water and the brain's emotional receptors where some are dulled and others enhanced. Much like the fauna of the planet, the people have also succumbed to this "love". Their lives are happier, they don't fight, they only aim to make life better for each other and the creatures on the planet. Every day is a paradise surrounded by wonderful things and people they love. Money, positions, power, recognition suddenly mean nothing as they are all tied to the greed economy that they left behind. They don't want to leave. When you have found paradise, why should you want to return to hell? They stop maintaining their ship and it falls into disrepair - what do you want a ship for if you're not going anywhere? Maybe they take the radio out so that they can invite their families and loved ones to come to join them in this paradise. Without the will to leave, the people won't leave. Love keeps them happy and love keeps them here. It may not be the same love as we know on Earth but it is a kind of love and it does not interefere with their everyday lives. It is logged by doctors and scientists after landing but considered harmless as the sources are completely natural and no negative or harmful effects are observed at any point. # Fear Of course, if we have to, we can take the above context and flip it - it's still a symbiotic paradise but people also gain an overpowering fear of leaving. So much so that they destroy/disable their ships and any incoming ones as soon as they have landed. This one is more likely to have some form of medical intervention as there are clearly harmful effects resulting from this (the destruction of ships) but maybe people don't really care about that at this point. Just hoping it doesn't extend to the total destruction of technology. I prefer the love basis but fear is more exciting and it's always good to have options. [Answer] Corrosive/damaging cloud layer affecting elastomer seals As ships arrive, they pass through the upper atmosphere, and then the lower cloud layers. They know the general atmospheric content, but didn't notice the clouds are acidified (or otherwise highly corrosive, or have other properties damaging to a craft in descent). Or, more sneakily, become so when heated or when they mix with hot chemicals that are in the thruster exhaust. The thrusters (assuming the crafts have thrusters of some kind) stirs up and heats the cloud layer. If the clouds aren't already damaging, the interaction with the exhaust makes them so. The ships then descend through this damaging cloud/product, and..... well, the metal is fine. But the seals are completely wrecked. Seals round windows and hatches, O-rings to seal in fuel dumping ports... All kinds of elastomers are embrittled. And,its not obvious, but this pervades just enough beyond the surface of the ship, to not be obvious what the damage is. (When an outside part embrittles, it stops protecting inner parts against cloud or condensed cloud stuff, so you get a penetrating effect, during or after descent. Or a risk of it, which amounts to the same thing) You can probably patch or cover corroded metal enough. But unless you have a factory to dismantle, rebuild, and pressure-test affected internal and external seals, for your entire ship afterwards, pervasive seal damage isn't going to be fixable. [Answer] ## No More Spaceship As many answers have suggested, iron-eating bacteria is the way to go. Create a baceria that uses iron as a crucial stage in it's metabolism, and watch your characters realize the problem as their spaceship dissolves before their eyes. ## Fuel Was Made To Burn Add some checmical to the atmosphere: something not harmful to humans, but something that reacts powerful to the spaceship fuel. And by powerfuly, I mean in a explosive manner. As soon as the characters open the fuel system to add harvested fuel, or to check on their fuel levels: KABOOM! ## Aurora Of Death Your planet has a particularly weak magnetic field, and your sun is particularly prone to solar storms. As soon as your ship lands, the vulnerable and fragile circuits are instantly fried. Sure, you can fix them, it'll just take a dedicated industrial base with hundreds upon hundreds of factories. ## Curiosity Killed The Octopi > > "Cool, this planet has animal life! They look like land-octopi. Woah, it squeezed into the spaceship! NO, DONT PRESS THA-" > > > The local animal life is curious, and curiousity killed it. And it killed your characters, too. Some creature has managed to make it's way into the ship, and it's pressed buttons that should not be pressed. Like, for example, the downvote button on this answer! [Answer] ## The planet is rich in samarium salts and cobaltite When you sent your probe ahead to scout the place, it landed using battery power and a parachute. It took soil and air samples and found a combination of a safe atmosphere and some pretty industrially useful elements that are not too common on Earth. This is wonderful news; so, next you send a colony ship... but this ship does not land using a parachute. Since you are a star-faring people, it probably does not land with chemical rockets either. Instead, it probably lands with some kind of nuclear rocket system powered by a tokamak fusion reactor. Unlike the parachute and battery lander, this ship melts the sand it lands on causing it to alloy allowing the cobolt and samarium to mix in the presence of the powerful magnetic field made by your ship. This results in the ground you land on turning into a whirlwind of tiny but very strong rare earth magnets that cling to the bottom of your ship. Not a big deal of course, since all of the electronics on your ship are already very well shielded against the magnetism of your fusion reactor... but there is one part of your ship not designed to deal with powerful magnets and that is the reactor itself. The intense magnetism from the newly minted magnetic dust alters the shape of the magnetic fields in the reactor just enough to breach containment melting a hole in the side of your reactor. Even if your crew could get rid of all the magnetic dust that just stuck to the side of your ship, and fix the reactor, they still could not take off without recreating the problem that blew their reactor to begin with. ## Why would these minerals cover the whole planet? On Earth we have an organism called thiobacillus ferrooxidans that only thrives in muddy environments. This bacteria uses a lot of iron in its biology; so, in places where this bacteria grows iron is constantly being leached from the ground and concentrated at or near the surface forming what we call bog iron. On your planet, most if not all life evolved to be reliant on cobalt and samarium as fundamental parts of thier makeup. So, over billions of years, as the top layers of the planet build one on top of another life keeps coming in, putting down roots and drawing these elements back to the surface. Over time this reluctance of life to let these elements sink down along with other elements will cause them to become more and more concentrated at the surface... so on this world, anywhere that life grows or has grown within the past few million years will have plentiful amounts of these elements. There may of course be a few safe places to land, but it will take scientists a lot of time studying the planet to figure out what causes this buildup before mission controllers can begin to make accurate predictions about safe places to land... and even then, it will always be a bit of a gamble guessing how long a place has been without life, and knowing whether or not the hazardous sand may have blown or washed in from somewhere else. [Answer] Thick atmosphere. This doesn't necessarily require super-high gravity (see Venus, for an extreme example) and doesn't necessarily violate the breathability or habitability requirements as humans can survive for extended periods of time at pressure of several standard atmospheres (see [saturation diving](https://en.wikipedia.org/wiki/Saturation_diving) for example). Thicker atmosphere means increased aerodynamic drag, which means increased [delta-V](https://en.wikipedia.org/wiki/Delta-v) requirements to get into orbit. In combination with a few other effects, such as slightly increased gravity, and slightly reduced rotation rates (so you get less boost from an [equatorial launch](https://space.stackexchange.com/a/15275/29766)) and unpleasant weather (denser air can exert more force when moving at the same velocity as less dense air) might all add up to enough to overcome your spacelaunch capabilities. Important note 1: Rockets can't quite be made arbitrarily powerful, but they can be pretty gosh-darn impressive: there can't be many planets which are habitable to unprotected humans that would prevent an [Orion drive rocket](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)) from escaping to orbit, for example. This implies that rescue is only a matter of time, unless someone comes up with a magical rocket-blocking mechanism that is independent of rocket power. And that sounds suspiciously un-natural to me. Important note 2: Being stranded on a planet due to ignorance of the above natural causes is to some extent an [idiot ball plot](https://tvtropes.org/pmwiki/pmwiki.php/Main/IdiotBall). Gravity and atmospheric composition and weather patterns can be calculated and observed from vast distances. Even some secret magic spacelaunch stopping mechanism requires that no-one send down a probe and have it return some samples of things it finds. Landing meatbags on an unknown biosphere without investigating it first is obviously pretty silly. Any suggested rocket-blocker mechanism will therefore require either the landing to be forced or accidental, or there be some [Golgafrincham Ark B](https://hitchhikers.fandom.com/wiki/Golgafrinchan_Ark_Fleet_Ship_B) situation. [Answer] The atmosphere. * Bacteria emitting flame retardant gasses (thus reducing the power of the engine) e.g. Bromtrifluormethan * Or your ships use nuclear fission reactors for powering a scramjet for the first takeoff phase, and the atmosphere contains too much xenon (neutron poison) so that you can't drive the reactor critical. [Answer] A captured Bok globule. The tricky part here is the "will affect all ships landing on this planet [...] they have been designed to reach orbit from similar planets." clause, since I read that as meaning that future ships should be able to freely land, and communicate, but will know in advance that they will be unable to take off, even if their mission is specifically designed for this particular planetary destination. This precludes economics/time as a concern, as well as just about all of the existing suggestions, so far as I can see. Anything unexpected that subsequent ships can be made aware of, or that ground crews can clear from a landing zone; anything that attacks material, fuel or people that could be shielded/protected in subsequent landers; volcanic effects (rocketry doesn't care); weather (would make landings harder than takeoffs); energy leeching (can't think of any approach to leeching where energy brought down in the ship couldn't be protected, apart from handwavey "the beam is sucking power straight out of the dilithium, Captain" type soft-science stuff). Our big problem: in general, landing in one piece on unstable ground or in an unstable atmosphere is harder than taking off and reaching space from a solidly built base under the same conditions. Given enough notice, ships can be made secure against whatever threat that would prevent liftoff. The only exception is that liftoff takes more energy, and that's a difficult one to prevent since energy can be brought down and protected. So, what about if we reframe the question. Perhaps what we really want is the "Bermuda triangle in space". A place that ships avoid, if they accidentally enter they are never expected to leave, where their navigational instruments will be useless, they will run aground, and will never have a rescue ship sent because it's known to be dangerous; but which nonetheless happens to be reasonably pleasant if you're wrecked there. So, is there some method that can make a planetary system act like a lovely atoll amidst hostile uncharted reefs? Kessler syndrome has been suggested and allows us to destroy the ships, forcing them to crash-land on the only viable planet; or to send out farm-more-strongly-protected escape capsules which can survive (or be small enough to mostly avoid being hit). But typically Kessler syndrome happens on a planetary scale. For this to work, it needs to be on a stellar scale instead: the whole solar system affected, perhaps more. Put the planetary system in a big ol' cloud of electrically charged space-dust and radiation blocking comms and visibility, so they won't know how Kesslery the area is until too late. Then it just becomes "that dangerous, uncharted nebula around that one star". Ships avoid it, and try to steer clear. If they're forced to take a shortcut through it, they either pass straight through without turning, or they get hit. Ships lost in there are assumed to be lost forever. Problem with normal nebulae: if it were the original nebula of the star's formation, then the planets that formed would have cleared the dust away, any remaining dust would have settled in the disk, and there'd be no problems. So likely this would need to be a small, dense dust nebula that the star has recently captured or is passing through. The nebula would need to have these properties: * Not many dangerously large life-ending chunks that might hit the planet and destroy all life; * Enough smaller chunks that a ship passing through the system stands a decent (1%?) chance of being crippled, but the route might just be worth the risk for some risk-takers or outlaws; * The small chunks would be accelerated by planetary gravity, so it'd get exponentially more dangerous as you approached the planet (making "running aground" there a near-certainty if you got too close?); * Lots of radio interference to mess with communications so mayday messages can't be detected from outside the system; * RF blocking interference also affecting navigation, electronics, object tracking, etc, like an old sailing ship having its compass messed with while in a fog; * Blocking visibility for tracking smaller objects, for laser comms, and for rescue ships to find deserted ships, thus making rescues impractical given the danger; * Allowing the planet to be old and temperate enough to support life; * Not blocking the light from the sun enough to prevent life on the planet, though it can have cooled a good few degrees from a desert planet to a temperate one as it went deeper into the cloud. By feeding on the dust, the sun could also get a bit brighter as it entered the nebula, compensating for the dimming of its light? Bok globule These seem to fit a star drifting into a filament of what is called a "[Dark Nebula](https://en.wikipedia.org/wiki/Dark_nebula)", or perhaps the small subtype of dark nebulae called a [Bok globule](https://en.wikipedia.org/wiki/Bok_globule). Narrative benefits This answer also has some visual/storytelling benefits, too. All that space junk it's passing through will give a constant show of shooting stars and incredible aurorae across the entire planet, both effects being perhaps even visible during the day. The radio interference could perhaps even be accompanied by space-lightning; not sure how that works in space. It also allows for other dramatic story elements: drifting "space hulks" in the nebula; other stars within the nebula could endanger the planet's parent sun, giving a longterm motive for finding a way offplanet; outlaws might hide out in the nebula, avoiding planets as they would accelerate space debris, increasing the risk significantly. Plus, "Bok globule" is just a wonderful name, and you want to be able to use that in a story. --- Speed of light This one's not a great answer to the question, but... the planet could just be a long way away, and not reachable by any other ships. Then any ship which crashes there will never see a rescue ship. This feels precluded by the assumptions in the question, but I thought I'd offer it as a possible solution just in case, anyway. [Answer] This is the case for NASA right now. Take the Space Shuttle program, for instance. The shuttle requires multi stage boosters to get to space. It can return to earth and land, but, if that "earth" didn't have civilizations with space travel capabilities, it wouldn't be able to get back into orbit, because it wouldn't have access to the boosters or fuel it needed. However, I'm guessing you want something that wouldn't be discovered until after landing. That makes it a lot more difficult, unless you want to go the direction that others have in their answers of the spaceship getting damaged/trapped by something on the surface. Based on the tyranny of the rocket equation, carrying enough fuel to land and take off again is far beyond our capabilities right now. Perhaps they never travel with enough fuel, but rely on the natural resources of the planet to mine/refine fuel from the planet to take off again. Perhaps it's a fusion based engine that requires tritium. Tritium has a natural abundance here in our hydrogen, but maybe there it doesn't occur naturally in high enough quantities to extract or purify it. Their planetary surveys indicated high amounts of water at the surface, so they were expecting to be able to source their fuel by extracting the hydrogen from the water and refining the tritium from that hydrogen, but that won't work anymore. However, I found out something interesting the other day about the [moon's gravitation](https://en.wikipedia.org/wiki/Gravitation_of_the_Moon): due to the presence of mascons, the moon's gravity is uneven, which results in there being only a few low orbits that are stable. Although we've studied this extensively with lunar probes, if this was one of the first visits to the planet, that might not be known yet. Say the spacecraft normally consists of a large component for interplanetary travel and a small shuttle. The large barge-like component stays in low earth orbit as the shuttle lands on the planet (this is how the lunar module worked). Normally, the orbital module would just stay in orbit and wait for the shuttle to return, but due to the lumpy gravity, it crashes. The shuttle is only able to get to very low earth orbit, and even then only briefly. Without the orbital module, it will not be able to leave the planet, and it only carries enough fuel to make it to that low orbit (not leave the planet). This could also add drama, because it might take time to figure why the orbital module crashed; was it sabotage? It would also leave them with a fully functional shuttle should they need to be rescued at some point, or which can provide assistance in combatting terrestrial problems. [Answer] ## SPECIAL ENVIRONMENT StarTrek Voyager actually explored this option TWICE and I strongly recommend you watch the following episodes (I'll provide just brief spoilers ahead): Season 4 Episode 24 (DEMON), Voyager runs across a Class Y planet (Demon class) and two members go down to mine resources. The strange liquid on the planet copies the crewmembers and creates new ones, which are unable to leave the planet due to its special atmosphere, meaning they're basically stranded there. The doctor on the ship describes this alteration as BIOFORMING, saying that just as we tend to adapt our environment to better suit our needs so did the environment adapt those newly made crewmembers to survive strictly within its own confinements. This storyline is further explored in Season 5 Episode 18 (COURSE: OBLIVION) when this recreated crew realizes they are actually clones of the originals and they're falling apart because the special liquid they're formed of is deteriorating. The second example is actually explored quite early on in Voyager, Season 2 Episode 25 (RESOLUTIONS), when the captain and her first officer are stranded on a planet because they've been infected by a bite of a unique insect, so the only way for them to survive is to actually remain on the planet where the insect originates because the planet provides some kind of environmental adaptation to keep them alive. If they try to leave without being cured, they die. [Answer] ## Dense forest The whole planet may be covered in a dense forest of huge trees with with strange intertwining branches. If something falls from above, the branches will relatively easily reversibly fold downwards, gently dampening the descent, so it is possible to land anywhere, despite the omnipresent trees. The folding is reversible, does no damage to the tree, and branches easily revert back to horizontal position once they are no longer pushed downwards. However, if a successfully landed ship tries to take off, the troubles begin! The branches will only fold downwards, not upwards. In fact, they are resisting any upward-pushing force, and trees and their branches turn out to be surprisingly strong. The trees receive only a minimal damage from an escape attempt, but it triggers something within them. A chemical reaction that reinforces that place, makes branches hold each other in an entangled way and causes them to secrete something nasty. It may either directly start damaging the ship (perhaps a strong acid) or it may be pheromones that will cause the local alien wildlife suddenly become hostile and see the stranded ship desperately trying to escape as a target. Everything may seem safe and peaceful until the escape attempt. [Answer] ## Economics A new colony - not just in space - begins by sending expendable labourers there to set up the new place, to make it not just habitable but actually worth living in. It is not in the economic interest of the people who own the ships to bring any of those first colonists back; it would be expensive to do so, and would not benefit anyone who gets a say over it. Perhaps it might be good for morale if they could return home, but on the other hand, they knew what they signed up for; it was part of the deal. It's perfectly plausible that those economic conditions could last for longer than a human lifetime; the only people who can go to that planet and return are rich people who would never plan on staying there in the first place, and perhaps they have no reason to visit yet. Terraforming sure takes a long time in reality. [Answer] # Atmospheric "Algae" Bloom Your rocket exhaust is food for atmospheric microbes. The robotic landers were too small to make a big difference, but the crewed lander's larger rocket tipped the balance. The microbes feasted on your rocket's exhaust, outcompeting other microbes, and disrupted the delicate chemical balance of the atmosphere. The increased number of dead microbes decay into something very flammable, preventing you from leaving. [Answer] 1. Unpredictable terrain. Without initial observations from rovers and probes, certain surface conditions may be missed. Because reasons x, y, and z the explorers decided to land on this uncharted planet themselves and skipped the lengthy probe/rover first missions. Once on the surface, certain details that could not be observed from orbit become apparent. The planet could have high level of tectonic activity with a very unstable, highly eroded surface. Once the heavy lander touches down on what seems to be level ground, become un-level due to the substrate and the very frequent tremors constantly rocking the planet. It would have once been very volcanically active, producing an abnormal amount of lava tubes, buried beneath the surface. Once the lander touches down, it immediately punches through into these tubes. It does not need to be much, just enough to make it off centered so the rockets cannot get a clean lift off. 2. Abnormal vegetation. Certain species on earth have a very rapid growth rate. Bamboo is known to grow several inches a day. If you had a species of vining plants that could grow several meters a day and is spurred on by the discharges of your space ship, the landing gear could get entangled quickly. If you delay at all to cut back the vines, they would grow exponentially. Eventually, to a point where your crew just cannot keep up with the growth enough to cut themselves free. [Answer] Solar Storm After the crew arrive on the surface of the planet, but before they leave, a large, persistent solar storm begins on the star of the system. The storm leads to high levels of radiation that are deflected by the planet's magnetic fields (so no one is affected on the surface), but would be extremely hazardous to any craft that leaves the protection of this field. Stellar storms are fairly normal, and many stars do go through periods where they become more active, so the explanation is very natural, although it does require a very sudden onset of unusually persistent storms. An explanation for this could be where the star is part of a binary system with a red or brown dwarf. Suppose the red dwarf has a highly elliptical orbit (like a comet) and occasionally passes within the Roche limit of the star. This would cause it to lose mass to the star which could destabilize the star and trigger the sudden onset of a period of much greater stellar activity, which could last as long as your narrative requires. Note that the storm does not need to be a continuous blasting of the planet's magnetic field with radiation. Regular intermittent (e.g. monthly) storms could also deter anyone from attempting to leave for fear that life support and electronic systems would be fried before they manage to escape the system when the next storm starts. People may not be willing to attempt an escape until decades after the star finally settles down. [Answer] ## Fake news The astronauts believe that they were lucky to get through the atmosphere the first time without [Insert whoever the boogie man of the day is here] shooting them down. If they leave they will die. They await help from their fellow [Insert name of political identity here] [Answer] If the planets electro-magnetic field is strong enough to fry the ships electronics then yes that or any other ship might be able to land (the circuits will fail when the ship enter the atmosphere but it can land using parachutes to brake it's descent), but never be able to take off. Basically the planets strong electro-magnetic field acts like an EMP grenade that fries the circuits of the ship. Even though there might be precautions taken against this very scenario, the caveat here is that the field needs to be more strong than the material shielding the circuits (electro-magnetic shielding, similar to when you don't get electrified if lightning strikes your car). [Answer] For really off the wall: Corrosive frogs. This is similar to the iron-eating bacteria answer. There's a native frog-like lifeform. Mating competition is a game of king of the hill, the frog that gets on top gets the pick of mates. Unfortunately, they excrete a contact poison that corrodes spacecraft hulls. The scouting was done on parachutes, but the real ships land on rockets--and the rockets confuse the frogs, as soon as a rocket lands all the local frogs mob it. A rescue mission has been suggested, but how do you hover on rockets and pick up people? The rocket would kill anyone around, not to mention the design requires local water for reaction mass, it can't do orbit to surface to orbit without taking on water. [Answer] ## Ever-descending lethal shells of energetic particles --- TL/DR: Ever-descending lethal planet-centered spherical shells of energetic particles in the exosphere caused by extreme planetary magnetism. --- An extremely powerful and reliably-periodic variable magnetic field emanates from the planet's poles, creating planet-encompassing sheets of ultra-high energy particles that will irradiate and bake any object that passes through. These sheets are separated vertically from eachother by wide "safe" regions where the particles are far fewer and far less energetic. Effectively, the planet's exosphere is like an onion. The particle sheets and the safe regions are both [say] several kilometers thick. The weight of these particles and the varying intensity of the magnetic field both cause these sheets to descend evenly over time. When they meet the atmosphere they create enormous and very predictable (and likely very beautiful) lightning-laced aurorae, which dissipates the sheet's energy, rendering it harmless. As the lower sheets are dissipating, new sheets are formed from particles magnetically ripped out of the atmosphere at the poles (this flow is even more deadly than the sheets). At any given time, the bottom [say] 5 or so sheets are deadly enough to prevent all passage through them. Old sheets dissipate and new ones are created [say] once every few days. A spacecraft can reach the surface intact by carefully orbiting within a safe zone between two particle sheets, matching its rate of descent, and waiting till the sheet below dissipates itself on the upper atmosphere. Then it can enter the atmosphere and land as normal. However, this phenomenon ensures there is no possible escape trajectory that will not pass through multiple lethal sheets. Any craft safely entering this system is likely to need to detect and deliberately avoid the sheets (unless it's ridiculously lucky). However, if you don't want to have the explorers knowingly imprison themselves forever you can possibly say: 1. They assumed the sheets were related to flares from the system's star. 2. They didn't understand the precisely periodic behavior of the sheets. 3. They were desperate to land and assumed they could figure out an escape later - perhaps underestimating the sheets' lethality. The layered effect of the sheets and safe zones could be due to a positive-feedback system where the particles are both attracted to the sheets and also help conduct the magnetic field - a good explainer of how this type of banding/layering can occur naturally is here (<https://van.physics.illinois.edu/qa/listing.php?id=27163&t=magnetic-field-lines-dont-really-exist>). While it's not essential to have variation of the magnetic field, it's probably easier to explain the descending-layered-sheet phenomenon if variation exists (and it gives you additional "degrees of freedom" in your story). Possible reasons for the reliable variation of the magnetic field could be: 1. A very fast elliptical orbit. 2. A moon with an elliptical orbit. 3. Magneto-thermal resonance effects in the planet's metal core. This phenomenon could also allow interesting weather, novel atmospheric chemistry, maybe even polar magnetic-field extremophiles. [Answer] ## Lack of sufficient quantity of fuel Getting into orbit require a lot of fuel. If that planet cannot provide the fuel itself, the only way out would be to bring enough fuel, which would need a way bigger and expensive ship to come and be stranded in its place. Space expedition could be used to have to resupply on site, but the survey of that planet failed to account for whatever issue about the resupply capability For oil (the basis of our own fuel), the planet could be too young to have built up reserve of oil that can be extracted and refined. Or whatever reserve of oil that have build up are too hard to get to. Or be contaminated with something the ship cannot filter out easily or at all. For other resources, the survey of that planet could have discovered reserve of that resource, but when trying to refuel, the reserve show themselves to be of way too small quantity, in hard to reach/exploit places, or outright of not enough quality/purity to be processed to resupply the ship. Note that while poor quality or contamination could potentially be overcome by bringing another ship with new technologies capable of processing it, an outright lack of enough fuel would ground down the ship until a new kind of fuel is exploitable, which may not ever happen. Also note that while bringing a bigger ship to resupply the first one is theoretically possible, but would be so expensive to practically ban it. [Answer] ## Electrifying animals cause problems Some animals on this lovely planet have a mechanism similar to electric eels. They find their way into the spacecraft and in the process end up frying sensitive electronics. The unfortunate astronauts aren't able to fix the components and are stuck until someone answers their call for help- but their transmitter is broken... [Answer] # Flammable atmospheric layer Landing on the planet is easy. It has a thick atmosphere, and modern probes and landers are designed to land without using large amounts of propellant. Once sufficiently slowed by aerobraking, the lander deploys a parachute and steers itself to a soft landing. To take off, landers use chemical rockets. They are sealed until ignition, so no airborne pollutants can enter, and the lift force calculations check out. Seeing no reason to worry, our adventurers land on the planet. The planet has a complex atmosphere. The lower atmosphere is heavy, saturated with oxygen and generally breathable, and the upper layers consist of lighter helium. Between both layers, missed by the probes (which were not actively measuring all the way down, were slowly descending on parachutes and only registered a transient course deviation that was ascribed to the weather) is a thin layer of methane, mixing with air at its lower boundary to form an explosive mixture. It was only discovered when the probes were launched on a return course to the orbital mothership and they all blew up at roughly the same height. Meteorites are rare due to the thick atmosphere, and lightning occurs on a lower level. While natural detonations can occur, they are rare and have not been observed before. The lander is now stuck, having no way to get through the boundary without hot engines. The only way to launch is by using a catapult, railgun or similar system to get above the methane and use rockets the rest of the way, and unfortunately our adventurers do not have an Ikea Spinl√•unch flatpack in their luggage compartment. ]
[Question] [ I have a fairly dystopian dictatorship with a police state. There are two ideologies amongst the population. The first - the more mainstream - in general support the rulers and the police and the wish to maintain the status quo. But there is a second, smaller, rebellious part of society who wants to overthrow the government and are very much anti-police, believing them to be hard-line freedom-haters. These are not criminals and certainly not violent, but they are not happy with the current state of things. But I've a problem. There is very little or almost no actual person-on-person type crime in this society (robbery, violence, etc.), and in fact, the police's main function is putting down the rebellious crowd - arresting people spreading anti-government propaganda and the rebellious leaders, breaking up meetings, hijacking people's individual initiatives to hand over to the government, and the like. So how do I justify the pro-government people's love of the police? I can't exactly show them protecting the ordinary citizens from muggers, wiping out organised crime, solving horrific murders, ridding the town of drug-dealers, rescuing children from child-porn gangs, etc, because there is none of that stuff. Edit Thanks for all the great answers, but judging by some of the comments, etc. I realise I probably left out a lot of potentially useful details: First of all this is a land of very scarce resources, causing poverty throughout the society. However, the government, and pro-government people believe that they are making the best of a bad situation and that the rebels will cause the structures that are there to fall apart, resulting in starvation and the potential destruction or decimation of the society. The police are relatively "evil" by modern standards - using excessive force, arresting people for the slightest anti-government sentiments (think "thoughtcrime"), confiscating things from individuals "for the benefit of society" sort of communist style (though it usually just ends up in the hands of the high ranking officials) - which is especially jarring because resources are very scarce in this setting, enforcing what we would call slavery (in one case hauling someone into work despite him being too sick). They are also intimidating in appearance. They have every reason to be hated, and in my personal opinion the best opinion someone could have would be indifference (if they weren't personally affected or didn't witness their evils), but in this scenario, I want the majority of the populace to actually like them, and, for example, be horrified when one of them is attacked in an uncharacteristic moment of violence by one of the rebels. The low crime is not, in fact, thanks to the police (though I understand propaganda could be used to make it look like it was), it is in the nature of the people not to commit crime, and in theory, no crime prevention would be required at all in this society. The police were actually introduced by the dictator to help him enforce his will rather than prevent crime. [Answer] > > I can't exactly show them protecting the ordinary citizens from muggers, wiping out organised crime, solving horrific murders, ridding the town of drug-dealers, rescuing children from child-porn gangs, etc, because there is none of that stuff. > > > You're looking at it the wrong way. A near-total lack of violent crime is a massive selling point for your dystopian regime. Point it out to the populace, and attribute it to the police force. Tell them that the police force is the only thing standing between the peaceful, crime-free society they enjoy now, and the lawless, violent wasteland that the anti-government protestors are clearly trying to turn their glorious nation into. Of course, it's not true. The police (if I understand your question correctly) are not responsible for the lack of crime. The anti-government protestors don't want crime to go up. But as every good dystopian regime knows, if you repeat a lie often enough, it becomes the truth. [Answer] The police are there to protect and serve. Protect from criminals, but also from other hazards and problems. * Little Timmy is missing? The distraught mom tells the police officer who is walking the beat, and within a few moments dozens of cops are searching. Happy news, Timmy wandered off from the playground to the park, but it could have been much more serious. * Old Granny Helen hasn't been at the grocer's today. Usually she comes every day to get food for herself and her two cats. So the storekeeper tells the officer, and the officer rings her door on his next patrol. The Granny doesn't answer, so the officer asks the building manager for the key and checks if she is OK. * New in town and disoriented despite the map? Ask the policemen at the street corner, they'll gladly answer polite questions like these. And as the dystopian government puts it, the opposition wants to stop all these good deeds. * They argue that the officer should have gotten a warrant before he entered the granny's flat. If she had slipped in the bathroom with a broken hip, she might have died. * They argue that the beat officer shouldn't snoop so much that he can recognize little Timmy on sight. Well, Timmy's mom won't call it snooping. Last but not least, the protesters can always be painted as criminals. Sure, there are not many muggings, but how about economic sabotage? At the very least, the protesters are vandalizing nice clean walls with their sprays. [Answer] ## Advertise them It's as simple as that. If most of people's contact with the police is irrelevant to actual police job, their opinion will be based on irrelevant factors. So, [dress your officers in cool uniforms](https://www.quora.com/Who-has-the-coolest-police-uniforms), let them [parade through the cities with their orchestras](http://3ww-aircadets.org.uk/archive/215_tenbymayorsparade_2013.htm), show them in TV, on billboards and posters as helpful and smiling. You don't need to invent anything, such posters existed and exist today. ### Some examples [Parade photos linked above](http://3ww-aircadets.org.uk/archive/215_tenbymayorsparade_2013.htm). USSR poster promoting militia/police. The caption says "Militia - People's servant". [![USSR poster promoting militia](https://i.stack.imgur.com/9yaRv.png)](https://i.stack.imgur.com/9yaRv.png) Polish poster promoting militia/police ([a while ago](https://en.wikipedia.org/wiki/Polish_People%27s_Republic)). Caption says "Policeman - your friend and defender" [![enter image description here](https://i.stack.imgur.com/Unssq.jpg)](https://i.stack.imgur.com/Unssq.jpg) [New Zealand's police recruiting campaign that went viral recently](https://www.theguardian.com/world/video/2017/nov/27/new-zealands-latest-police-recruitment-video-goes-viral). And yes, that stuff actually works. ## Fighting with opposition may sell better then work against regular crime! Dystopian dictatorship should have well-working propaganda. Show opposition as trouble-makers. Present them as working for enemy force. Present statistics of how their actions hurt economy (you don't need to measure anything; just make them up). Highlight the police role in keeping order. Extra points: show any opposition actions as hitting people in everyday life, like affecting the price of sugar, or anything in that vein. Your goal is no less than to make people blame opposition for everything bad, especially things like hurting teeth and bad weather. You don't need to invent much, just study a bit of history. Or even look at some propaganda today. [Answer] Police are also fire and rescue. [![police fire truck](https://i.stack.imgur.com/F5tpa.jpg)](https://i.stack.imgur.com/F5tpa.jpg) There is already a lot of overlap between these functions as is evidenced by this NYPD fire truck. In your society the same group of people serve all these functions. People love their firefighters and ambulance folks because they come and save you. If those people are the police too, they love the police too. [Answer] Police are people. They have barbecues and children, they go to basketball games and churches. It is easy to chat with one without realizing or caring they are a cop in social settings. If 90% of the time they are Andy Griffith most of the people won't have to know that they are also Jack Bauer. If the police are fairly effective at shutting down dissent the people happy with the status quo might not have an accurate picture of why there is dissent. "Rebels are anarchist looking to have freedom to kill, steal and rape." regular people will rather have a burger with a sheriff they went to school with than pick a fight with the men with guns. If the police are actually giving the security and safety they are billed as without too much corruption or abuse keeping a counter movement going seems harder to explain than people liking cops. [Answer] A image is worth a thousand words So, we start with the uniforms, your police officers should be elegant and refined, their uniforms may not be the most practical, but it sure will be the most elegant. You want even your enemies to look at your uniforms and say: I mean, they are an evil dystopia, but their uniforms are stylish as hell! Moving pictures are worth even more You have the cool uniform, now it's time to show it around! You pump the entertainment industry full of that sweet bribe/incentive money. In short, any movie that decides to portray your police officers in a more... elegant light will receive lots of helps from the government. Just give a read about what the US Department of Defense does with their financing of Hollywood movies. Action on the Streets As it has already been said, your cops should be the friendly type, they are not going around carrying automatic guns and threatening people, they will help kids set up a lemonade stand or old ladies to cross the street. But, you will also want your cops to look like badasses, so make sure to "find" a few terrorists safe-houses here and there and have the cops in full gear march inside to save some poor 10 year old blonde girl that was kidnapped by the evil terrorists. Friend of the people, enemy of the people Finally, criticizing the cops should be considered impolite in extreme. It don't matter if you are a kid protesting against the closure of your school, if you say shit about the cops, then you are Satan and deserve to swallow a whole bottle of pepper spray. The media will be your best friend here, just make sure they always spin any incident in favor of the cops. Say these cops just plowed trough a bunch of high-school students, just make sure the media focus on how the students were in fact evil commies out to kill blonde babies. If you can't spin the story in favor of the cops, just disappear with it. What, you still believe in the Downtown massacre? That's some paranoid bullshit! Why do you hate the cops? [Answer] Let's not just think of the police as a force that catches criminals If you really think about it, crime is nothing but a definition (L.Dutch is dead on about that). What the police are actually doing is protecting the average citizen from the inconvenience, discomfort, offense, damage, or injustice caused by someone else. And in your world the only people appreciably causing inconvenience, discomfort, offense, damage, or injustice are the protesters. Why wouldn't the population love the police? They don't interact with them on a daily basis, they're courteous when you do meet them, whenever you hear about a protest you also hear about how effective the police were at stopping it. What's not to like? What? What about my neighbor, Marty? Well... he's on extended vacation. No I* certainly didn't see the police enter his house. Marty's never comitted a crime in his life! Well, the door's locked. How do I know? I watched the police check, just to be sure he didn't leave the stove on or something. A very courteous thing for the police to do, too!* Anyway, if you're worried about the traditional definition of police: a group that enforces the law, then make laws. Your dictatorship certainly has them. The last thing it wants is to be perceived as lawless or simply brutal. You want trials. You want justice! You need laws — dicatators simply ensure they're the laws they want and those of no one else. [Answer] As @F1Krazy, no crime can be a selling point. One side benefit of a well run tyranny is stability. After the somewhat recent chaos in Romania, there are many who wanted Vlad Tepesh back: because there was no crime. And that's true. One story is of a foreign merchant who ask Tepesh for some guards to protect his goods. Vlad was incensed by this saying that no one would dare steal it. He then ordered the merchant to leave his goods on the street corner for a few days. After those days were up, upon inspection, nothing had been touched. As long as the police don't dare commit crimes against the populace, they will be seen as a social positive. Now, lets take the question title into account: How to have a competent police force in a low crime society. Competent compared to what? The criminals won't have a lot of practice. Sol the police simply have to be better than the criminals and get them off the streets before the criminals have a chance to gain experience. [Answer] Crime is not a "bad" action per se. Crime is what the law defines as such. Just have your government ruling that spreading anti-government propaganda is a crime, and those who do it will become criminal. As such most of the population will appreciate the police getting rid of the criminals, who with their action endanger the peace and prosperity of the almighty nation. [Answer] Easy... Manufacture terrorism or crime. If there is no one you can order to do it directly, or you do not want to actually do it, then "radicalize" a depressed youth by entrapping him. Convince him to carry out a terrorist act and provide him fake explosives. Arrest him just before he does it. (Example: <https://en.wikipedia.org/wiki/Amine_El_Khalifi>) The other answers are good too, and if you have control over mass media (and know how to use it), propaganda can achieve anything. But if you have a free press, then you need to do some work. [Answer] Dictatorships often define themselves and achieve popular support by using the threat of an external enemy. For example North Korea, Iran and Cuba have all used the United States as this enemy, and claimed to be defending their populace from American aggression. The violence of the police can then be justified by the magnitude of the threat that they are protecting against - terrorists, saboteurs and fifth columnists introduced by this enemy. They will be popular because the alternative (as shown in government propaganda) is seen as much worse. [Answer] You write: > > The first - the more mainstream - in general support the rulers and the police and the wish to maintain the status quo. > > > And then > > the police's main function is putting down the rebellious crowd > > > Now you ask: > > So how do I justify the pro-government people's love of the police? > > > So the Police maintains the status quo. Ergo all People who wish to maintain the status quo, and believe they already live in the best possible "system" would love the police. Simple as that, don´t even need to stress propaganda. You even have enough examples, if you look into other regimes like Gestapo or SS in Nazi Germany where supporters who liked the current regime wanted it to stay that way. [Answer] If there is little or no crime (and the police aren't stopping any), people must be pretty happy in general--the other option is fear and if your people were in fear, the police wouldn't be an issue, they would have to be active to cause the fear and lawfulness. So they are pretty happy, perhaps there isn't enough work to keep everyone busy and one of the things the government does as a "works" program is rotate citizens through the police force (Kind of like our military reserves). This would give them a large, strong police force with a reason that people would empathize with and support them. [Answer] Social Anxiety can be a persuasive force Many developed nations today invest enormous resources into police, anti-terrorism forces today even though crime rates are quite low compared to both history and with other countries with higher rates. Why? When you are affluent, you are more afraid of society losing cohesion and devolving into lawlessness. This fear increases when crime rates decrease, and is essentially societal anxiety. This could actually result in broad support for your dystopian dictatorship, and justify costly expenditure on internal security. As wealth and income is accumalated in society, there is more to lose, and more reasons to justify more expenditure and police presence. It is the same feeling that is capitalised on by insurance companies. Eventually the risk alone would make it hard to justify a reason not to increase spending in such a manner. [Answer] Government mind-control television signals have convinced the populace to like their police force. The signals don't work on a small subset of the populace. To put it another way, people love the police because "they love Big Brother." [Answer] How your rebels and pro-government fractions feel about each other? Do pro-government people fear for their life and future because of what those rebels are stirring up? Do they feel like they need protection? Do they think that police is the only thing that keeps the order, keeps the entire civilization from collapsing? Sure those people in uniform are the finest and deserve all respect. [Answer] If the majority is pro-government, wouldn’t they appreciate the police preventing the loss of that government? If you also have them do nice things for the cooperative whenever they get a break from doing mean things to the uncooperative … [Answer] Pax Romana was Pax Romana because everyone who wasn't peaceful was killed. That's peaceful relative to rome though. So that's this society. This society is like rome. There is no crime because everyone who commits the slightest infraction or even thinks about it is quickly and quietly removed from the rest of society and killed. The people who are left love the police. Government propagada takes care of the rest. Another thing you could do is to make the people believe the police are demigods,or maybe agents of God. The police could be led by some one thought to be a god. Bring religion into it. It has been done before. [Answer] In a society facing large issues with scarcity then it can be seen as government bringing stability and revolution bringing chaos. People may be worried that a revolution could mean interruption to their already meagre supply of resources. If food is scarce then that means revolution could bring starvation. This would set people against revolution out of fear and make them praise the police for shutting it down. A dictatorship could carefully control its image with propaganda and restricted areas to ensure any wealth officials had is not seen, and therefor not a motivation to revolution. ]
[Question] [ Imagine quite a way into the future, the Earth becomes overrun with humans. Birthrates are similar to where they are now, and the advancement of medical science means that people live a lot longer (say average life expectancy is 150 for the developed world). We are, at this point, in frequent contact with species from other worlds, who (with us as a member) have formed an intergalactic federation. The Federation has decided that the human population of Earth is too great, and have given Earth an ultimatum that we are to reduce our population from 120 billion to 8 billion (if this is too large, the Federation may be open to negotiation) in the next 20 years. The means we use to do this are up to us. Presumptions: * The technology level of humans is assumed to have moved at a realistic rate * All major political powers are open to working together towards this requirement * Most governments still care about ethics, and aren't up for just randomly choosing people and shooting them. * The Federation will take action if we do not attempt to carry out their ultimatum. So, what would be the most humane way to select people to die for such a good cause, and how would it be done? [Answer] ## War Clearly the most humane way to choose the people is to get volunteers. It's likely to be hard to get volunteers for the problem as stated. So instead ask for volunteers to attack those members of the Federation who voted for this proposal. This could be combined with a draft. People who do not wish to be subject to the draft can accept a one-in-seven chance of living and mandatory sterilization. Those who fail the one-in-seven chance will be humanely terminated. If we lose the war, our population should be drastically reduced. Combined with birth control at or below replacement level, this should solve the problem. And of course if we win the war, we've gotten rid of the Federation and are no longer subject to population controls. This is the only humane way to proceed. Anything else is simply capitulating to tyranny. This also has the side benefit of improving leverage in negotiations for a longer term of population reduction and/or an increase in the allowed population. It also gets around a big problem. Assuming current fertility rates continue, how would a country like Japan react? They currently have a shrinking population. How would they feel about having to give up around 90% of their population to cover for population gained in other countries, like India? ## Unrealistic This whole thing seems unrealistic though. First world countries like Japan or those in Western Europe already have declining native populations. If the entire world was rich enough to have a life expectancy of 150 years, it seems likely that this would be even more of a problem. The world population may continue to grow for a while, but in a hundred years, I'd expect the concern to be switching to the possibility that we're going to die out due to lack of children. This would be more realistic if set soon enough in the future that our population is still growing, say 2050. Obviously our population won't be 120 billion then. Perhaps twelve billion with a reduction to one billion. And of course our life expectancy won't be 150 years at that point without some major changes. [Answer] I only see one way to do it humanely: Negotiate with the Federation to get the technology to quickly build lots of huge space habitats/habitats on other planets and transport the humans there. Now if you manage to negotiate a longer time frame, comparable to the life time of a human, then you have one more option at your disposal: Implement very strict birth control. [Answer] The 120 billion of humans fight for their survival against federation, if won we colonise whatever planet/spaceship they live in. Earth (considering vastly superior future technology) can easily sustain 50bil people, rest are sent as colonists. The Federation is destroyed and their leaders dead. [Answer] Assuming negotiation is not an option: 1. Strict birth control. You do not have to kill what is not (yet) born. It will have little effect in scale but let's be honest every single life counts. 2. Ask for volunteers. Will make some little difference I suppose. 3. Promote extreme sports. Same as above. 4. Stop treating the terminally ill. Harsh but it will save some lives. 5. Set up a Survival Determination Project. Should be the most popular URL instantly. The Survival Determination Project What is needed is a fool proof mechanism to select survivors from among the total population. To ensure popular support and compliance, and to eliminate political wrangling this needs to be thought out and created publicly, with open and probably vigorous discussion about the why’s, how’s, and when’s. Initially I used RFC (Request for comments) for this concept but it is indeed more along the line of an open source project, as @celtschk rightly pointed out. The project should provide for: 1. Some kind of raffle. In the end you need some random way to spread survival chances among the to-be-reduced living population. Better be absolute foolproof. 2. Some kind of life gift method. Can only be given, not asked to avoid mass coercion. So must stay secret until day zero for the recipient. This way parents are able to give up their meagre percentage to their children. 3. Possibly gladiator games can be introduced for those who want to fight and/or believe in survival of the fittest. Gives the rest something to watch while it all plays out. Interesting times indeed. [Answer] I believe the most "humane" reaction would be to flip this Federation off. 120 billions of people would most likely not appreciate being bullied like this by some abstract "Federation", and would most likely throw the politicians which are okay with this out the nearest window. It would take probably less than a day for any politician which is okay with this to not be okay with this anymore. Everything goes on the table then: 20 years ? Make that 2000, and we can talk business. 120 Or: to 8 billion ? Make that 120 to 80, and make that 1 billion decrease every 100 years. The point is that as far as people would most likely be concerned, cutting even 1 person by decree will be unacceptable (the "by decree" part is the point). A planet-wide armed riot / civil war is very possible. How can politicians prevent the potential self-annihilation of the civilization on the planet ? They can either: * Enforce compliance, starting to weed out people and turning the planet into an armed dictatorship (people will resist and will fight). * Ignore the directive, accepting the repercussions. We're back to the population feeling bullied. * Flip the federation off, dropping out from it. People would be happy-ish (no more "cut back on the population" nonsense) until the inevitable consequences (I foresee import/export difficulties and frantic attempts to keep friends with neighbour civilizations and/or the federation itself) My point being: politicians might be okay with it, but the other 120 billion people won't be. This kind of demand can't possibily be open to negotiations enough to become likeable. Either party has to fold to prevent open conflict. [Answer] Mass hybernation. People are frozen and stored in underground storages. Then they can be awakened at some shedule, then hybernated again. The technology exists today but currently used only for recently dead people in hope the medicine of the future could cure their deseases. It was also tested on animals. [Answer] In Dan Brown's Inferno a mad scientist releases a rapidly spreading virus that causes infertility in about 50% of all people. It cuts the population by a drastic amount without actually causing anyone harm, though it is delayed by about 1-2 generations. [Answer] Set Baby Rights Allocate every woman the amount of 1/2 of a baby allowed. A couple or a woman can sell or buy the rights to a full baby and give birth to one. Allow the Free Market to Take Over A woman (single or as part of a couple) that has the means to buy the allocation of others, can have a full baby or more, if they have the cash. This way, a woman who, for example, may be impoverished, can sell her allocation (probably for a lot of money). This evens the playing field a bit. In a lesbian couple, one of them can have a baby (two half-allocations) or they can 'buy' more baby. Women who are unable to conceive can sell their allocation and can pay a couple to adopt, but that's a different story. Two men who want to adopt will just pay whatever it costs to adopt someone who has had a baby; this will be more expensive, because unlike a heterosexual couple they do not start with 1/2 allocation. [Answer] Computer Avatars [2045 Initiative](https://en.wikipedia.org/wiki/2045_Initiative) comes to mind. This organization says that by 2045, we will have analyzed the brains complexity and will be able to upload our self into a virtual reality world. Instead of a body we would have an avatar (and in the future, a real-life "robot" avatar). If this technology exists, it might not be hard to convince the old and the young to live in this simulator. [Answer] The federation sounds pretty unintelligent to think that you can remove 85% of a population in 20 years without any adverse side-effects and I'd wager we could outwit them but let's assume they're just mean. Assuming there's a roughly equal amount of every age, you can prevent 7.5% of the population via birth control, and 7.5% would die in those 20 years so we can safely ignore any new births and expect 7.5% to die right from the top. The moon is roughly a quarter the size of earth, and assuming 120b people are living on earth, 30b of those people could live on the moon since it's very likely the technology to do so is entirely there. * With this knowledge we can strategically place 25% of the population (under 130 years of age, so as to not have any die) on the moon. (30b safely away) * 7.5% of the total population will still die, but as they're all on earth and this will make sure the moon stays at full capacity upon inspection day. (9b from natural death) At this point we have 73b people left to work with to meet the demands fully via humane means. It's not looking too good. Hopefully they can be made to reason with us as we've almost halved our population in a matter of 20 earth years without a single shot fired. All good things take time and hopefully they may see the value in allowing time to take its course and we can be left to continue our means of population control by sending the old to earth and keeping a persistent 30b people on the moon until 8b remain on earth. *or* The Federation eliminates all humans on earth and we persist via the strategically placed youngest humans on the moon. (Sorry gramps) [Answer] # Colonoize another planet, or live in space You mentioned that technology will be growing at a good rate. We're already have probes on multiple planets, and the commercial space industry is exploding, so its reasonable to assume that by the time your scenario comes around we'll have much better inter-planetary transportation abilities. The bigger question is, why does this federation of aliens care how many people are on Earth so much that they are threatening us? [Answer] Want to improve this post? Provide detailed answers to this question, including citations and an explanation of why your answer is correct. Answers without enough detail may be edited or deleted. To reduce the number of humans on earth we will use our advanced biological science to mutate 112 billion humans on the planet to become lizard men. Thus by definition we have reduced the human population. If the federation is not amused by our trick then we will send the lizard men after them (who of course are naturally well suited for war). [Answer] A most (hu)man(e?)ly method would be to start a war with The Federation. (Given their demands it should be easy to get global support for it) War will always cause casualties, and as such will reduce the population at a fast rate. Whether Earth wins or looses, the population objective will be met in the end. [Answer] Negotiate over the time-line, we will need about a human lifespan (according to the comments possibly a lot longer). Then make everyone rich. If we have achieved space travel it seems probable that a post-scarcity society would be technological possible. The only reason it hasn’t happened already is we still have a class system imposed by our free market. Free markets tend to favour people who start with wealth to invest, this enables them to generate more wealth with greater ease than people who cannot make an investment. However with this ultimatum from the Federation we suddenly have a very strong incentive to stop this nonsense. The governments will redistribute wealth right across the globe. When families are wealthy they tend to have fewer kids or none at all. Japan and Germany both experience population decline for this reason. The truth is that we could do most of this today. If we redistributed wealth to places that currently have very high birth rates, then their child mortality would fall, and their economic prospects would rise. It wouldn't take much to greatly increase the quality of life of many of us. Lets not wait for an alien ultimatum, lets do this today. [Answer] "Birthrates are similar to where they are now" In lots of developed countries, birthrates is lower than 2 ! Which means that without immigration from poor countries population would decline (in fact Japan could even lose all its population within some hundred years given its current birthrate). So the answer is sample : make underdeveloped countries developed so that they undergo a demographic shift. [Answer] There is no way to 'humanely' reduce the population by that much in twenty years. You can see this if you picture yourself at somewhere between 20-30 years old in the here and now, and then imagine that only 6% of the people you know at that point in your life are alive 20 years later. Even taking someone who is 60, you're still describing mass slaughter. This is assuming that you aren't using the meat industry's definition of "humane" I suppose. But even then, the idea of "humane death" is one that decreases suffering as much as possible. If you're going to announce that 94% of humanity needs to die in the next 20 years, you're pretty much announcing an inhumane outcome. So yeah - war with Federation it is, like other people said. There's no sense in trying to reason with a bunch of genocidal maniacs. [Answer] Well if you are George Lucas you have some really cool options. You file a Form 382-G with the intergalactic courts to get them to stop the process. (Get them tied up with that for a while.) You're going to also probably want to file for a HIQ9 restraining order at the same time. But that's going to cost because you're going to have to hire process servers to serve papers to each federation world leader, AND you're going to have to take out a full page legal notice ad in the intergalactic news beacon next month. Then you file a Z-91 notice of foreclosure (with a NV-56.121 notice to vacate attached) against each member of the federation home worlds. You don't really have a case but they're still going to have to prove it. Now that's going to buy you a good 60 years or so. Of course you mustn't forget to file a bunch of motions with the senate subcommittee on population control. It would be ideal if these were as confusing as possible as you want to tie up the process as long as possible. Then you haul over to the interstellar transportation board and file to have a toll zone put in between Mars and the ort cloud. You'll probably have to pay a few bribes for that one. So you give them Pluto (Jokes on them, it's not eve a planet anymore.) Of course, the toll zone isn't going to keep them out forever, but everyone knows they aren't going be paying that toll just come check on you. So that bought you some time. Now what?.... Now you just wait about 20 years, green screen the whole planet and digitally alter it to make it appear that people that were there aren't there anymore. Just to round it out you fill in every empty space with random creatures for no good reason. Then make a nice film about how barren your planet is and send it back to the federation senate, where they watch all of about 20 minutes of it and silently all vow to pretend like the entire thing never happened. [Answer] The way I see it, nobody would take the risk to accept this ultimatum in front of the populations. Since a democratic choice would lead to chaos all over the world, I think the only realistic way would be to do it without the consent of peoples. Some deadly viruses/diseases could be successively unleashed like the [1918 flu](https://en.wikipedia.org/wiki/1918_flu_pandemic) or Ebola and that could decrease the population a bit. Keeping only 1 percent of a human population seems really a difficult task. Some nuclear war may be efficient enough to kill a huge amount of population but who would pull the trigger ? [Answer] Freeze them Freeze the excessive population (choose who to freeze by lottery, age, geographical area ...) and implement strict birth control to prevent new people being created. When somebody dies, unfreeze someone to replace them. [Answer] According to the WHO 56 million people die each year. With the population at 120 billion, even though people are living older and the fact that medicine would have presumably improved, I don't think this would entail the mortality rate being proportionally lower per capita, as the state of being a lot older actually would nullify the improved medical treatment. So I'm going to assume a mortality rate in proportion to today's, that is (56 x 17) 952 million people a year. Assuming reproductive rights were strictly suspended by the powers that be, and this injunction was adhered to by the citizens, or successfully enforced by the government(s), to drop down to a population of 8 billion from 120 billion would take 118 years. That is IF no extra person were born in that time. After this period of 118 years, those who were babies at the start of the reproductive ban would be 118 years old, and eight billion humans would be between the ages of 118 and 150. The 118-year-olds would be the youngest generation. If you assume the mortality rate per capita to be LOWER because of improved medicine, then this 118 year span would become longer. Even if you quadrupled the mortality rate, so that it were just under 4 billion people dying per year, it would still take, all other factors held constant, about 28 years to accomplish an 8 billion population goal. This is assuming NO new births, and no voluntary or involuntary euthanasia. The most destructive war in terms of lives was WW2, which claimed (higher estimates) around 80 million people. And in my opinion, a great portion of these were non-combatants dying from famine, disease and genocides. So that's 80 million in a 6 year period, that's 13 million per year. Well it's a start. The deadliest earthquake on record killed about 800,000 Chinese. The Black Death of medieval Europe wiped out between a quarter to half of it's population (50 mil to 200 mil). This is a measly 10 to 40 million people a year. The Spanish flu of 1918 killed between 25 and 50 million people a year. So with extra mortalities thrown in we'd be getting there. But don't forget this is with a complete ban on reproduction. Assuming a complete baby ban, and a mortality rate per capita four times what it is today, we'd be sitting around 28 years to achieve the goal. To reduce that time to 16 years about 900 million people extra would need to die per year. Likewise, you could assume a mortality rate of 8 times what it is today, per capita, and the natural number of attrition would drop the population down to 8 billion after 16 years, that's about 8 billion people dying per year. Did I mention with a complete baby ban. [Answer] I think we can hardly better Johnathon Swift's Modest Proposal in 1729. "I have been assured by a very knowing American of my acquaintance in London, that a young healthy child well nursed, is, at a year old, a most delicious nourishing and wholesome food, whether stewed, roasted, baked, or boiled; and I make no doubt that it will equally serve in a fricasie, or a ragoust. I do therefore humbly offer it to publick consideration, that of the hundred and twenty thousand children, already computed, twenty thousand may be reserved for breed, whereof only one fourth part to be males; which is more than we allow to sheep, black cattle, or swine, and my reason is, that these children are seldom the fruits of marriage, a circumstance not much regarded by our savages, therefore, one male will be sufficient to serve four females. That the remaining hundred thousand may, at a year old, be offered in sale to the persons of quality and fortune, through the kingdom, always advising the mother to let them suck plentifully in the last month, so as to render them plump, and fat for a good table. A child will make two dishes at an entertainment for friends, and when the family dines alone, the fore or hind quarter will make a reasonable dish, and seasoned with a little pepper or salt, will be very good boiled on the fourth day, especially in winter." Just scale up the numbers and sell to the Federation [Answer] To reduce population you need to focus on two things, decrease birth rate, and increase death rate. Fastest way to increase death rate, will be start conflict. It will be very easy to construct it. If federation create that kind of demand, in next step people will split into two groups. one which agreed with those terms, and another which will against. Now few "terrorist" attacks, and large anti-terrorist operation should successfully help to decrease population to required limit. Other solution, is much simpler, just increase costs of health service and costs of living and promote unhealthy life style. To decrease birthrate, I see two solutions. One was described in Dan Brown book, Inferno, which was virus which made 1/3 humanity infertile. Other one, will be to introduce Laws which allows only some people to breed. [Answer] An "intergalactic federation" spans between galaxies. Why are we worried about population on one planet? The implication of FTL travel and significantly vast energy scales means people should colonize new worlds and artificial habitats. With the technology of hundreds of billions of worlds, and substantially higher technology implied by FTL etc and because some worlds will be much older, the carrying capacity of one planet will be significantly higher, too, not limited by the energy of the sun. So your premise needs to be at least quantified better, or certainly explained and justified better. [Answer] First someone should ask in which [frame of reference](https://en.wikipedia.org/wiki/Frame_of_reference) are those 20 years defined. If the federation people are constrained by the speed of light and moving at relativistic speeds, then it is quite possible that those 20 years are actually a significantly longer time. Even if time dilation is not a factor, the distances involved are. If they do have faster-than-light travel, then Earth could kindly ask to borrow one of the time machines they certainly have and a) destroy or undermine the Federation in their past or b) teach our Bronze age ancestors abstinence. I'll leave the various paradoxes and ways to avoid overshooting the target as an exercise... [Answer] Personally I agree with the folks suggesting war. But, if for the sake of argument that isn't an option, there is perhaps an actual humane way if the Humans can negotiate two things - a longer time period and for the 'federation' to cough up some money. The solution would be to pay people not to have children. If the federation is powerful enough that it feels it can issue a mandate to humanity, then it clearly has incredible resources. If they are willing to part with some, they can offer humans large payments in exchange for accepting permanent birth control. It is a win-win transaction for everyone involved with minimal coercion. If payments are large enough, then enough people will accept them. Over the course of an average human life-time, you'd see a significant drop in the population. If its not dropping fast enough, the federation ups the payment. If its dropping too fast, they lower the payment. There could of course be cheating (freezing eggs, using surrogates), but DNA tests at birth should stamp out the majority of it. [Answer] @thkala's answer was almost perfect, but missed one implication of the Federation having FTL capabilities... FORWARD TIME TRAVEL 1. First of all, sterilize all but 8 billion people and hold those still fertile humans in reserve for the last step of the process. 2. Acquire several of the Federation's Time Machines. 3. Divide the remaining 112 billion people into groups of 8 billion people each; carefully balancing skills and capabilities so that every group has all the knowledge and experience needed to thrive on their own. 4. Send each group of 8 billion people into the future, advancing each group forward 150 years farther than the group before. Each of those groups can then live out their lives in total before the next group arrives to take their place. 5. After all of the other groups have gone forward, send the 8 billion fertile people to the empty world which follows the death of the furthest sent group. It is their job to carefully propagate the human race into the future. Once that fertile group has left, the Federation can come pick up their time machines so that nobody is tempted to misuse them. Note: This could also be done without Time Machines if the Federation could supply enough star ships to contain the 112 billion (otherwise time-travelling) people. Those ships would travel out on vast circular routes at heavy time-dilating speeds in such a way that enough ships to offload 8 billion humans, would return to Earth every 150 years. Note: It could also be done with cryogenics, but that might not satisfy the Federation because the 112 billion frozen humans might still be considered alive, making the entire effort moot. [Answer] Late to the party, but I had a shower thought (literally) Choosing people at random is the only way that will be viewed as fair and acceptable. But of course those chosen to die will go to war against both galactic federation and human leaders that serve them. Instead, the rulers of the earth will need to reframe the situation. Evil empire has infected the Earth with a virus, but Galactic Federation has generously provided billions of doses of vaccine. So we randomly choose those who will receive it. Ofc, the virus would need to be made and distributed in secret, but earth government or the Federation. Federation's own weapon is is probably a virus anyway. Any other weapon of mass distraction will mess up the planet, and if they do not mind messing up the planet, they would just blow it up with exhaust from their intergalactic drive. [Answer] In Mass Effect the solution was spreading the disease that makes most victims sterile. But again, it needs about 0.75 times of a lifespan to bring result. The real humanely way is to send everybody to another planet, may be cheat the aliens with classic "genie wishes" trick. [Answer] First I want to say that it's impossible to have 120 billion humans on the Earth but well, it doesn't matter right now, sooner or later all of them will be dead in some way. # Birth Control Rate It's an slower rate but it's quite ethical. By this way it's impossible to kill 120 billion humans, but if you prohibit them having any children (even if they want children you can sterilise them, I don't know if it's possible in humans but it's possible to permeate with gamma rays in mosquitoes and is very fast and cheap). You could also make a deal to increase the human survival or increase the time limit you have to do it. Personally I think it's impossible but if humanity shows that they are trying to complete the deal (even out of time) the Federation could give them a second chance. Obviously you can not stelize useful and smart people, it is your chooice. Also, you can make an aleatory process (or selected) where people who lose (14 out of 15 people :)) have 2 options: * Be executed. * Be sterilize. # Controlled Plague A faster way could be using a similar method used in [Utopia](https://en.wikipedia.org/wiki/Utopia_(UK_TV_series)). * Bassicaly they make an `Alpha` protein which is given to humans secretly in cereals (and other types of food I think). * Then 7 secret persons fly 7 planes (planes used to irrigate field crops) but instead of irrigating with water or insecticide they irrigate the cities (yes, the 7 most important capitals, not farms) with a lethal sickness (Black Death). * Finally, the US government gives free vaccines to all the American citizens and also gives vaccines to other countries. These vaccines contain the `Beta` protein which causes a chemical reaction with `Alpha` proteins: + This sterilises randomly 95% of the human population. This "attacks" humans bodies only if they have a certain `Z` (I would say X but maybe it would bring confusion) gene, this gene is almost random in the human population. + Also (it wasn't totally planned in the series) this `Alpha-Beta` combination can destroy the human immunity to the black plague, making it more lethal. + They said that in 100 years the human population would be stabilized to 500 million humans. In your case, it would be 7.5 - 6 billion humans. Important people could have the real vacine (without the `Alpha` or `Beta` protein). Basically you can poison (or a sterilising drug), water, food or even a person (like a plague?). # Reduce Medical Care * Terminal and non-terminal but lethal diseases are not allowed to be healed by medics. * Suicides and bloody accidents aren't treated by medics. * Vaccines aren't given to humans. * People in comas, vegetative states, intensive care, etc... disconnected. * Medical drugs replaced by placebos. If you don't want to make a revolution you can instead make it very expensive. Rich and smart people (who often are rich or at least have friends) won't die. # War War is very useful, it's waged mostly by volunteers and there are a lot of deaths. * Countries could make wars to kill people, maybe the country who loses would have to "sacrifice" more people for the Federation. * The world's population could make a war against the Federation. + If they lose, human overpopulation would be almost resolved. + If they win, there is no more human cap. # Other methods, quite... dangerous. * Poison Water: you can poison the drinkable water (or at least make it sterilise humans) when humans reach the 8 billion you can make a vaccine and also stop poisoning the water. (You can distribute fresh water or vacines to VIPs). * Controlled Droughts: secretly governments could destroy crop fields (drought by removal of water, controlled insect plagues, fire) to make citiziens die by starvation. VIPs generally are rich or smart (and with rich or other VIPs friends), they won't have any problems buying food. * Melt Ice Poles: yes, it's a crazy idea, but if you melt the poles a lot of people would die from drowning, then if you stop heating them they would slowy freeze again (right???). * Nuclear War: obviously. * Biological War: like the controlled plague but on a bigger scale (this would be in your enemies countries not on your own). ]
[Question] [ Closed. This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 1 year ago. [Improve this question](/posts/231592/edit) Assume the prophecy says that The Chosen One will defeat the DARK OVERLORD. The spell of the prophecy is always accurate and has a 100% chance of being true. This has been mathematically proven and is consistent with all the observed outcomes of prophecies. So now The Wise Wizard Mentor has found himself a Poor Farm Hand or Traveler From Our World who turns out to be the victim of the prophecy. Obviously, they should receive training from the finest warrior and mages The Good Guys have. But is any of this, including The Wise Wizard Mentors intervention really necessary? After all, it is known that The Chosen One will defeat the DARK OVERLORD. So anything that happens is supposed to happen. So what if the Evil Legions slaughter The Chosen One's village. So what if they don't train. So what if they show up to the Final Battle in stained underpants, stoned out of their mind, and utterly wasted. The prophecy is true and this is known. They will win no matter what they do because they don't really have the option of losing. Anything they do was foreseen and it turned out to lead to their victory. Or am I missing something here? Is there a way to have accurate prophecies involving no uncertainties which come true no matter what if their preconditions are met and still get the opinion of an actually meaningful story? [Answer] ## The Prophesy is Assured, but the Identity of the Chosen One is Not The Prophesy does not tell you who the chosen one is, but it does tell you about the nature of the chosen one. If a man has fulfilled 47 of the Prophesized qualities of the chosen one, but there are 48 qualities he is supposed to fulfil, then the man you have is not the chosen one, and therefore can not defeat the Dark Lord. If you were to follow a false chosen one into battle, then your failure is assured; so, you must be certain that you have the real chosen one. The training of the chosen one is not about the hero being trained to beat the Dark Lord, but to make sure that he meets all 48 prophesized qualities before he goes off to face his fate. Maybe your mages have found a man who was born in the right town and can cure the sick and raise the dead and do many of the things the Prophesy says the chosen one can do... but it also says he will be brave, self-sacrificing, and in the greatest hour of need, he will choose to give up his life to save the world. So, if the guy you found is selfish and cowardly, then the only way this man COULD be the chosen one is if you teach him to be brave and put others first. Otherwise, you are stuck waiting years or even centuries for the next guy to come along who might meet all the qualities you are waiting for. Then there is the Dark Lord's motivation. If the Dark Lord knows a guy has fulfilled 47 of the 48 prophesized qualities of the chosen one, then his only hope for success is to off this guy before he can fulfill the 48th quality. After all, if the hero dies before he's fulfilled all the qualities foretold in the prophesy, then the Dark Lord is not actually beating the Chosen One, it just means the Chosen One has not come yet. [Answer] Victory, but at what cost? It is only the victory that is prophesized. But a victory can be a good or a bad one. Maybe the chosen one dies. Maybe he's left crippled, mentally or physically. People might die, maybe 90% of the population, maybe the Wise Wizard Mentors. There is a big difference between a pyrrhic victory and an "actual" victory. An example, if you ignore the story's prophecy: In Star Wars, Anakin Skywalker was victorous over the Sith - in a way. He killed Emperor Palpatine... ignoring sequels. A prophecy wouldn't care that he became a Sith himself and only turned back to the light side minutes before his own death, and after causing billions of deaths. The better the training, the higher the odds for a better outcome. [Answer] IS IT DETERMINISM? Your question hinges on free will and determinism. There are two possibilities: Deterministic Universe In this prickly scenario the universe is deterministic. Not only is the chosen one's fate predetermined. But so is everyone's fate. We don't get to see our own prophecies but are nevertheless powerless to influence our own destiny. So should we train the chosen one to achieve their great destiny? Or should we not bother and eat potato crisps all day? You will be happy to know that in a deterministic universe the question of should is meaningless. So don't worry about it. Semi-Deterministic Universe In this scenario some things are preset. The Chosen One will always defeat the DARK OVERLORD. But the rest of us can decide our own destiny, subject to all the prophesied stuff happening. Importantly we can determine the manner in which the DARK OVERLORD is toppled. We can marshal our armies and train the chosen one in the Secret Arts. In that case we can defeat the DARK OVERLORD in a Final battle on the slopes of Mount Doom. Then we establish a republic and [give out free motorboats](https://www.youtube.com/watch?v=YJKHw_CNYP4). [![enter image description here](https://i.stack.imgur.com/pkkZG.png)](https://i.stack.imgur.com/pkkZG.png) Or we can eat potato chips all day. In this case the DARK OVERLORD is still toppled. You see after 60 years of tyranny, the DARK OVERLORD boards a public bus as part of a PR campaign. The chosen one was on the same bus and unwittingly sneezes on a safety rail. The DARK OVERLORD touches this safety rail and contracts influenza. Due to extreme age this ultimately leads to the DARK OVERLORD passing away. His heir takes up the job and is twice as tyrannical. [Answer] It is possible that this prophecy is accurate because it chooses somebody that is going to make decisions and choose things no matter what. Their destiny compels them to do so. They may not even believe in prophecy, they are going to train anyway. Just like, if my prophecy is that the Sun will rise tomorrow at 7 AM, and it does, it is because this is in the Sun's nature, my prophecy is based on that nature. It does not force the Sun to rise at 7AM, it just knows that it will. So goes prophecy. Now the fact that it is made may prompt the wizard to find this individual and offer them training and magic; and the nature of the individual is to accept this training and defeat the evil, thus fulfilling the prophecy. Such prophecies are called "self-fulfilling" prophecies; it is the fact that people (like the wizard) believed in them that makes them come to pass. Like somebody telling a child they are far too stupid to attend college; and the child believes them, so doesn't even bother to pursue academics, and thus cannot even graduate high school, much less attend college. Either way, in fiction you can make both the prophecy of something that was bound to happen anyway (like the sun rising at 7 AM) or the self-fulfilling prophecy work out, without breaking any logic. I'd say let the wizard and the hero contemplate this within the story. The wizard can explain. > > "Perhaps it was destiny for both of us; for me to heed the prophecy > and for you to fulfill it. Or perhaps you were always destined > to prevail against the Overlord, and my resources only hastened > your victory. Perhaps we both had a choice. I could have ignored the > prophecy, but chose to pursue it. And you could have stayed home, but > with the offer of my aid, you chose to pursue justice. We cannot know. > The fact that the prophecy was made and fulfilled tells us nothing." > > > [Answer] ## You're prophesying wrong This is a classic question, but it fundamentally misunderstands the role of future-telling in narrative fiction, which means that following this thread will never lead you to good or interesting narratives. ### The role of prophecy is not to resolve your major story conflict The reason your audience needs a prophecy is not because the prophecy is what guarantees that the heroes win and the villains lose. That guarantee is actually provided by genre conventions: in some (many) genres, the good people ultimately defeat the bad people and justice prevails. (Other genres exist where the good people lose, or achieve a Pyrrhic victory, or nothing is resolved, etc.) People generally know what to expect on this score before they read page 1 of your work. No, the role of prophecy is usually one of: * propel a nobody into greatness In the real world, it is extremely rare for a person of initially low station to decide the fate of the world. Social and power structures being what they are, people at the top tend to make all the decisions, and those decisions usually include making sure they and their children stay at the top. Fate/prophecy is a tool that lets an author escort their homegrown nobody to the top tiers of the ladder. It is the diegetic manifestation of the author's choice of protagonist. * create a mystery for audiences Prophecy is usually expressed in natural language: it's a written text or a specific utterance, generally very brief and thus necessarily rife with ambiguity. The mystery then is: what final, complete state of affairs will obtain which is consistent with this fragmentary description? Even if the prophecy appears to be bald and unequivocal: "The hero Jerry Farmhand will slay the villain Murdero Slaughterton on Thursday at 5:17pm," there is actually still plenty of wiggle room regarding other facts that the audience will care about. Does Jerry survive the battle? What happens to Murdero's beautiful captives? How will we feel about the death of Murdero when we know more about him? Etc. The importance of the prophecy is not that it is "proven" to "100%" of reliability, but that it provokes a specific kind of playful game between the author and the reader: the author promises the reader that story events will ultimately be consistent with the prophecy, but by implication essentially warns the reader that she will care less about the specific facts revealed in the prophecy than about the other "peripheral" facts and the sequence of events leading to that state. The prophecy about Jerry Farmhand is practically a notice from the author saying: "you may think the most important story arc here is about whether Jerry can ever defeat Murdero, but I'm telling you you're wrong, and to show you how serious I am about that, I'm going to tell you right now: Jerry does kill Murdero. Now hold my beer." * sometimes, it's part of a lesson about language itself I think this is less common, but one thing prophecy stories have in common with the genie and wish-fulfillment genres is that they very crucially hinge on the characters' ability to articulate themselves. One of the minor lessons of stories like The Monkey's Paw (and other evil genie stories) is that achieving one's goals requires that (1) one actually be fully cognizant of all the facts about which they have preferences, and (2) find a way to express their whole intent concisely in their natural language -- to fully express their will. That maybe seems silly, but bear in mind that law is literally a kind of technology that humans invented, no less so than flat-panel televisions and pacemakers and solar panels, and so every generation needs to give their kids the tools that are needed to get by in a society of laws. That means you have to be more articulate than is required by ordering food at a restaurant: you must anticipate and preemptively defeat the ways your interlocutor might wish to defy your will. Prophecy stories invert the sequence of cause and effect, essentially challenging the reader to work backward. All of these concerns transcend Jerry Farmhand's decisions and the question of predestination, because fictional narrative's interest in prophecy is very different than it would be if prophecy were real. Prophesy is ambiguous in every story you've ever read, but not because nobody has yet had the audacity to publish a completely explicit, totally locked-down prophecy, but because doing so typically leads to really lame narrative results. Would anybody bother reading a story about Jerry Farmhand drinking, smoking, and refusing to do laundry or prepare for his epic battle because he has a cosmic guarantee of success? No, they would not. But you can write one if you like. [Answer] Does it say what happens after the victory? If not, then the Dark Lord may simply be replaced by the second in command. Your prophecy is come true, but everyone is boned nonetheless. But here's the thing: you have the one guy (or girl) that is certain to live up to the moment the Dark Lord is defeated, so he's the best candidate for any and all dangerous missions. Maybe send him out to kill the subordinates of the Dark Lord to sow chaos in their forces and lure him out before you fulfill your prophecy? That would not only support the prophecy but also the wider world. Additionally the chance of the hero surviving increases, which they'll appreciate. [Answer] ## Same thing as time paradox. * based on your axiom - The spell of the prophecy is always accurate and has a 100% chance of being true. Mages do not need to bother to train the guy, maybe the guy slips on a babana peel and accidentally kills the ultimate bad guy But on the other hand, they may choose to help the guy for their own benefits, assuming it helps the CO to achieve his goal faster, and for him not to be a last guy on the planet, who kills the ultimate bad guy when no one actually cares anymore. They (mages) may choose to help, but it does not mean their choice will matter, it still may be a banana peel accident, or 1000's different ways with or without help of the others. (That's why that CO is so good, write whatever, no need to think so much on a plan) If the good guy is killed right at the start, it was just a wrong guy (but that a bit murky territory depending on your setting in which way they identify that CO, how do they find it, but also not a big problem in 1000's ways - they do not have full knowledge about universe, nor control - if they teleport one they can teleport few accidentally, or split bodies, or whatever) So you can (in your fantasy world) have ultimately true prophecy, but same way as in the reality the same event may be achieved as result of unmeasurable number of consequence chains, connections, coincidences. That stoned good guy on battle field, it even fails to create a slight disturbance in reasoning, because of not having full information about the ultimate bad guy - maybe they will find each other and smoke bong together for long an happy life, and once drunk accident happens again, damn banana. So even if I said it similar to time paradox, but in fact it is quite far from it, and examples you had in mind(wrote down) do not do even a ripple as paradox does - it is just two points with unrestricted paths between them. To have a paradox here it needs to have 2 ultimates/absolutes here, at least. ## Prediction in general Being able to predict something with absolute certainty for all the cases - not likely, but predicting itself as for some events it is more common that it may feels at a first glance - if I drop a stone from a plane, there is very slim chance it does not land on the surface of the planet(if I did it in the way it does not end up in a plane engine). Difference from 100% is negligible, and similarly we do rely on predicting of consequences of events in our technologies, it basically all about getting expected results for most of the time for expected set of consequential and parallel events - start a car, fly a plane, make cpu crunch numbers, etc. Those are predictable, because they have some robustness against external events - potential barrier which has to be crossed to change it, so a movement of a random atom next/near the observable setting/system has a very slim chance to change expected outcome. (Slim means so close to 0 that you can't have seen such a number - so small it is) So there are predictable events, and in a sense with certain power and ability to have/collect data - outcome of CO vs UBG also can be(maybe) predicted close to 100%. And how close to 100% your guys do not really know, as they are not source of that estimation, but are just users, and they not necessarily have stats to judge(a billion predictions is good stats, but without knowing how it works it gets us to just 99.9999999%, way worse than dropping stone from air plane). So robustness of prediction depends on bifurcation points, some we do know some we do not(we are quite good, usually, identifying them in our tech stuff), but better the ability to collect information, and better prediction algorithms better the results of outcome(there are fundamental limits, it has to be some macro level events, human brains is something in between, murky territory, but it reflects in events on macro level). And when there are few or none bifurcation points - prediction can have certain probability(a bit more complex than just that, but for simplicity). * in a sense CO is not necessarily the only guy who has capacity of killing UBG, others may have lesser chances to do so, but they are capable to do so, but they have more bifurcation points which if they cross them in a right way they may have that 100% as well, but they do have bifurcation points which makes their chances uncertain or less than 100% In that sense CO is just one of with a set of development path's(which he has many as anyone) where each of those path's has no bifurcation points. It basically about all that: * If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle. - @Sun Tzu, The Art of War - (probably) In that sense a valid prediction, it less likely rely on some accidental event as path to success, or events, and it makes more sense for mages to put efforts in helping the guy. ## PS - Free will Can't avoid to add few point to that big topic, as some of the answers dive in extremes - determinism or free will. Free will does not mean there is only unpredictable outcomes when it hits a human. Yes, a hundred years ago, or earlier it could be philosophical conundrum, enigma. But today we all can observe that behavioral patterns do exists - the whole advertisement model is build around that, focus groups, recommendation algorithms etc. So some of them are one offer to many, some are many offers to one - and it works, sometimes better some times worse - but prediction works. What creates complexity, is interaction in the society between agents, not only people vs people, but people vs environment, which diminishes the importance of freewill or not. And as an example it possible to predict that most of viewers of the question will eat tomorrow, also as result of some will, as they can choose not to, same as the guy who wants to prove me wrong(write a comment btw, you are awesome, outstanding warrior of "someone is wrong on internet"). If we knew all the people, who will read it, could we determine if there is a guy who may make such a choice - choose to not eat - yes, we can try do so based on his behavioral patters. (Fbi joins the chat). Our predictions are not perfect, and ways are not mature, but still. It harder to predict who will actually read it - as it is a result of pvp and pve - but does not mean it impossible at all, or that presence of freewill stops us. There are strategies, habits people use, and in a sense we less free, aren't that fluid to render any possibility of prediction impossible. Sure we have uncertainties, but the whole theory of ideal gas is build around random/chaotic movements of molecules(agents) and we have certain outcomes, our prediction works - not any set of chaotic events can make us helpless to predict at least something, and in some cases it can be CO vs UBG, in some cases we even do not need much to make such conclusion and prediction (wunderr waffe and genetic code to activate it, as an example) So to have certain predictability there is no need to plunge in deterministic world, and we do have good results with chaotic not deterministic systems, predicting them, so as there is fuzzy logic approaches etc all kinds of things to deal with chaos. So there is certain map of expectations of probabilities with certain uncertainties in them, and this map may have some unique guy whos network of probabilities ends up in slashing UBG, with or without other forces involved. Such events are probably rare, but it may exist, and may be visible for something which has sufficient strength to crunch numbers. Does not mean he is only one, but just one who can be seen. [Answer] In ancient Greek and Roman myths men are not allowed to know their fate and even many gods don't know what was decided by Fate. Oracle and prophecies were vague and incomprehensible. The most common thread even in modern stories is that not even the most powerful of the wizards can really be sure that they have really found the chosen one until the very end. [Answer] ### Don't make the prophecy subject your main character. The Chosen One follows a predetermined path to the letter, overthrows the Dark Overlord and brings peace to the universe. There's no uncertainty so no suspense: so, don't make him the protagonist. Have your actual protagonist(s) ride the tide of the war and meet personal challenges along the way. The central conflict of your story won't be the world war, it will be the struggles faced by individuals fighting in the periphery. The people trying to make their ends meet as the Chosen One under his halo tramples on their livelihoods, perhaps doing them just as much bad as the Dark Overlord himself. You can make a compelling story involving an inevitable prophecy, if the story doesn't revolve around it. [Answer] ## Historical example... ... of winning a great victory without bothering to do anything. In August 1914, in the [Second Battle of Tannenberg](https://en.wikipedia.org/wiki/Battle_of_Tannenberg), a German army of 150,000 men led by [Field Marshal Paul von Hindenburg](https://en.wikipedia.org/wiki/Paul_von_Hindenburg) destroyed a Russian army of 240,000 men led by [General Alexander Samsonov](https://en.wikipedia.org/wiki/Alexander_Samsonov). The battle was fought near the city of [Allenstein](https://en.wikipedia.org/wiki/Olsztyn) (which nowadays speaks Polish and is called Olsztyn), some 30 km (20 miles) east of the village of [Tannenberg](https://en.wikipedia.org/wiki/St%C4%99bark) (which has also adopted the Polish language as is now called Stębark). The Germans, masters of propaganda as always, named in the Battle of Tannenberg in order for it to be seen as revenge of the terrible and decisive defeat of the [Teutonic Knights](https://en.wikipedia.org/wiki/Teutonic_Knights) by [Władysław Jagiełło](https://en.wikipedia.org/wiki/W%C5%82adys%C5%82aw_II_Jagie%C5%82%C5%82o), Grand Duke of Lithuania and King of Poland, in the [First Battle of Tannenberg](https://en.wikipedia.org/wiki/Battle_of_Grunwald) back in 1410. What did the glorious victor, Field Marshal Paul von Hindenburg, who was 67 at the time, do to win this glorious victory? Nothing much. Basically, he showed up in his splendid uniform and let his Chief of Staff, [Major General Erich Ludendorff](https://en.wikipedia.org/wiki/Erich_Ludendorff), do the work without interference. As [Major General Max Hoffmann](https://en.wikipedia.org/wiki/Max_Hoffmann), who was then in the General Staff of Hindenburg and later became Chief of Staff of the German Eighth Army, used to explain to visitors to the battlefield later in the war: > > "This is where the Field Marshal slept before the battle; here is where he slept after the battle; here is where he slept during the battle." (As quoted by [Barbara W. Tuchman](https://en.wikipedia.org/wiki/Barbara_W._Tuchman) in her book [The Guns of August](https://en.wikipedia.org/wiki/The_Guns_of_August), 1962.) > > > Being asleep while in command was apparently a lifelong habit for Hindenburg, whose fame comes mostly from being the President of the German Republic who appointed a certain Mr. A. H., leader of the National-Socialist German Workers' Party, to the post of head of government in 1933. As a consequence, the battlefield where Hindenburg won his crushing victory is now in Poland, together with almost the entire province of East Prussia. (The part which is not in Poland is in Russia.) The point being that sometimes [Being There](https://en.wikipedia.org/wiki/Being_There) is all that is needed, as amply illustrated in the famous American film [Forrest Gump](https://en.wikipedia.org/wiki/Forrest_Gump) (1994): > > "The story depicts several decades in the life of Forrest Gump, a slow-witted and kindhearted man from Alabama who witnesses and unwittingly influences several defining historical events in the 20th century United States." ([Wikipedia](https://en.wikipedia.org/w/index.php?title=Forrest_Gump&oldid=1093970375)) > > > [Answer] The chosen one wouldn't do this : * How do you know he is the real chosen one ? If he sits on his ass, he'll get himself killed and it will be revealed that another one was actually the chosen one. * Imagine, if you are told you are the chosen one, would you drink a big glass of cyanide before jumping 20m in a pool of acid while stabbing yourself with a knife, just to see what would happen ("i'm the C.O., i can't die before killing the bad guy, so i will survive somehow") ? If yes, you would actually die, because you wouldn't be the chosen one, because the chosen one can't be an idiot like that. So the chosen one would be someone who either wouldn't think of it, or would realize there's many flaw to it and will put on the work. It can be helped with some self-interest, like the prophecy says he will kill the bad guy, but nothing on his survival, so he better train if he want some chance to live. [Answer] ## Whatever they're doing, it leads to the prophesy being rendered true. There's no element of choice or free-will here. What they do is always going to be part of how they defeat the dark overlord. They will eventually defeat the overlord. This is a fact. The path they choose through their life ultimately WILL lead them to this outcome, no matter what they do. If a certain course of action would make it impossible to do that, it cannot be what they'll choose to do. They don't opt to sit on their laurels. They don't choose suicide in the face of the philosophical conundrum about their personal agency. They don't fail to rise to the challenge. The path is set. The outcome is certain. It's not a question of whether they can or can't be lazy about it. Cause and effect are effectively reversed. Effect dictates cause. The Hero will eventually do what is necessary. [Answer] We can lean into science fiction here. Time travel stories with a singular, unchanging consistent flow of time exist. They deal with this problem in a few ways. One of them is that the most likely way for the information you gain to be true occurs. If you make it nearly impossible for the plausible ways for the information you gain to be true, then implausible results happen. For example, suppose you have a prophesy machine. It shows you a picture of what a die will roll in 6 seconds in a box. What happens if you take the die you see in the box, and you mark it? In 6 seconds, a die looking just like this without the mark will be in the box. An implausible or improbable series of events happens and the result always happens. If you aren't scared, you should be. Because some of those implausible events aren't going to be very friendly for you living through the next 6 seconds. The harder you force it to be impossible for the picture you see in your perfect prophesy machine to occur, the more insane the scope of the things that happen beyond your control in the next 6 seconds will happen. This device is basically a temporal bomb; generate a picture of a future, block that future, and insane amounts of force will occur to force that pictured event to happen. Blocking a prophesy basically has the same effect. It will happen. If you are blocking it from happening, the way in which it happens has to render your ability to block it from happening ineffective. So suppose you find the chosen one, and get them to avoid training. Well, an easy thing to happen that would make this reduction in the likelihood the chosen one defeats the dark one would be you dropping dead of a stroke. Or, someone stabbing you. Or you tripping and breaking your back. Or a the chosen one deciding you are evil and killing you first. There are many, many things that are less unlikely than "chosen one never trains and defeats the dark one" that would block your plan of "chosen one never trains". By actively or passively getting in the way of a prophesy, you are not dooming the prophesy -- you are dooming yourself. And the larger a barrier you are to the prophesy being fulfilled, the greater the doom. [Answer] Gods are cruel master sure, you have been chosen and the prophecy tell that you will win, the god made sure of that... that is if you do your part. god will have no shame internviening to smite downa prick that tought he could not do the work and get to be teh chosen one. Maybe they will straight up kill him , change the prophecy or create another prophecy that is more important than the precedent one, or all kind of divine intervention, but one thing is sure, the great force of nature don't take too kindly those that ridicule them. do the work or go home prophecy kind of suck language is a tricky thing, especially for a young oracle high out of her mind on her local divinatory mushroom. so they will be able to spell something that barely make sens and need to be interpreted broadly... And ono top of that, fate is not fixed in stone so thing can significantly vary from what was seen. All of this combined make that if you don't try your best you might prophecy are just to damn good if fate is unmovable then you staying in the castle to enjoy wine will have no bearing on the result, because the fate knew you were going to do that and expect that it's how you will defeat teh evil lord. don't ask me how, that's just that everything was already written and somehow you will defeat the dark lord by being. and beside the last case on top of nothing being guranteeed, a lot of chosen just happen to be overdramatic asshole who like making the whole thing as spectacular as possible [Answer] The infallibility of prophecies (and what it means for prophecies to be fallible) is completely up to the competency and creativity of the author - and free will tends to hit every step on the way down regardless. If you specifically want to focus on a prophecy which guarantees the Dark Lord will be killed in 10 years, focus on what the actual "heros" are going to do to stop the dark legions from pillaging the land for the next nine years and how everyone is going to stop the Dark Lord from detonating his superweapon before it happens (to inflict maximum damage, not kill himself). Plus there is the issue of the diplomacy were different factions may not want to pull their weight if they think other factions are going to be the ones to take the brunt of the suffering in the next 9 years. As a real(ish) world example, assume it was confirmed that Putin had terminal cancer with 3 years to live and that Ukraine would without a doubt (somehow) conquer Russia in 3 years time. How would you prevent Russia from launching its nukes and what would be the politics between the different nations who could be in the fall-out zones of the explosions and the other countries that had been supplying Ukraine with weapons. What is the perspective of a Ukrainian soldier on the field. What is the perspective of a Russian soldier on the field. What is the list of objectives of a swedish diplomat at the UN during this period? ect. The important thing to remember is that prophecies tend to guarantee exactly one thing. One death, one defeat, one event. The state of everything else in your world is utterly unspecified by that prophecy however and still has to be fought over to ensure. [Answer] Here are some solutions: * Do not make the prophecy their destiny; while it tells the future, it does not have to certain it will happen, depending on the conditions. * Have a terrible cost; while the hero may not do anything, he will eventually defeat the Dark Lord, but at the cost of the destruction and death that happens because he did not do anything. * What if the chosen one becomes the villain himself; after the defeat, they may like the fame and money, leading to a god complex, and you can guess what happens next... * There may be multiple chosen ones, and the protagonist may want to keep his title. * He may somehow benefit from the villain, and will worry about the consequences. [Answer] You could lean in on the apparent paradox. Suppose it's been prophesised that a promising young warrior will defeat the evil overlord. Everyone knows about this prophecy and how it is guaranteed to come true. And as a result the Chosen One decides he doesn't need to train any more. He doesn't need to wear uncomfortable armor or carry an awkward weapon. He doesn't need to take care of his health. After all, it is indisputable that he will save the day, no matter what. Everyone who is counting on him regards this development with horror, but they can't talk him out of it. Even the Evil Overlord hears about it, and changes his plans as a result... Well, I won't write the whole story, but I think the reader would at least be curious as to what would happen next. Maybe the hero's laziness somehow saves the world? [Answer] # Malicious compliance Who's to decide who is the dark one and who is the chosen one? Come the fateful day, if the guy everyone assumes to be the hero hasn't done their homework... The fates will just decide that the guy doing all the killing is the actual chosen one. They may pick an even worse guy to be the actual dark one later. The prophecy is still fulfillable, the new chosen one is a properly prepared person and the auditors of reality are satisfied. Bonus if the guy who was previously considered the dark one has a backstory similar to the wimpy one, so more checkboxes can be checked. [Answer] # There are multiple prophecies about the Chosen One - and not all the things they're prophesized to do generally are considered good things. The prophecy does say that they'll defeat the Dark One, but it itself doesn't say how. Other prophecies do, and some of the steps seem...worrying. The type of stuff you generally want to prepare for, or prepare them for doing, so that they can be done well, and safely, and...not causing unexpected problems. For example: "The Chosen One shall break a reservoir to flood a city to thwart the Dark One." Okay, fine, it's guaranteed and it'll thwart the Dark One...but which city> Is it the City the Dark One uses exclusively, like [Isengard](https://youtu.be/Iw0jwrWqOKI?t=67)? Or is it some peasant city south like if this had gotten out of control south of [Rivendell](https://youtu.be/1eNkwaWvUzg?t=197)? The current city? Or the "Old City" version of the city that's been moved away from? Are we dealing with a man-made reservoir or a natural one? Do we just keep the Chosen One away from all reservoirs and cities with water sources, or do we let them integrate into society and just keep a close eye on them until we discover "Okay, this city needs to evacuate all its civilians." moments before they come to realization they have to fulfill that prophecy? Oh, and I guess we should help them a bit by getting them to know all the blueprints of any reservoirs they happen to be nearby, maybe with some safety valves and open/close doors that can be re-used, such that when the Chosen One breaks the reservoir, they do it in a minimal way that reduces the amount of infrastructure work to fix it. Add a few more of these, and it becomes more of a matter of determining "Okay, these are all 100% going to happen - let's work out where the rest of us can wriggle in this prophecy to avoid un-prophesized losses.". Since you're going to keeping a close eye on them and working around whatever they do that fits the prophecies, you'll probably want to get to know them a bit more, so you might as well mentor them as well. [Answer] Let me answer by providing analogy. It has been prophesied many times that if you learn 10 new words a day, you will will have learned 3650 words before the year ends. Why hasn't it been fulfilled? Well, it was—for some. Why is it so hard to complete? Well, human condition. I believe fiction leverages that exact feature of reality: to motivate us to fulfill our destiny, promising great things if you do X. No fantasy is ever to be taken literally. [Answer] If a prophecy is a view of the future come back through time then that event would always happen, accidentally or on purpose. Then no training matters for the event to happen. It will happen. John gets a text message and pulls out his phone, and trips over a mop bucket rolling from the side hall way. John, gets up and reads the text message, “I saw in a dream you fall down in the hall at school.” If the prophecy is a self fulfilling prophecy then the chosen one(s) are people who train and make it happen. Is indiscriminate mostly. “One day someone will fix this dam!” The few villagers get together on the weekend and fix the dam. If the prophecy is conditional it would have tests. The prophecy is that John will be a leader of a company then that person going to business school and studying and inventing things is a trial to see their effort and that project will be granted. “If you are faithful in little you will be faithful in much.” But it’s not really a project but more like a goal with rewards. In that case reading makes a difference. King Saul didn’t want to be king or couldn’t handle it so it was given to King David. Most people say to, “Keep moving. Don’t give up. Keep going” because the destiny is unseen and moving forward reveals more of it. Gandalf couldn’t see all end but felt that certain characters had a role to play. Prophecy could also be wishful thinking by people or the gods. Tell the prophecy that a savior will rise up and see what happens. It could also be useful for getting everyone to concentrate their resources on requiring one person to do a job. I personally believe you should train for the position you want and be ready for it. Or that sometimes life trains you. And without training it may happen but there may be more struggle. There may be a time where the protagonist train but nothing happens and then later an opportunity presents itself and that fulfills the prophecy. This is college degree for many people. “I dreamed I would be a scientist and got a degree but I work at Starbucks as a barista.” - then one day years later they discover a cure for something. If you can’t change the future then doesn’t matter what you do concerning the prophecy. It will happen. Training might even interfere with it. John heard the prophecy and is always worried about it and his life sucks instead of enjoying life. In Botw, they know that the villain is returning and prepare for it. But for all those preparations it doesn’t matter. Some of the preparations are redeemed but mostly they are a nuisance. [Answer] > > Is there a way to have accurate prophecies involving no uncertainties > > > No, this is not possible due to the inherent limitations of language. In your example, many things are unspecified, such as when and how the dark lord is defeated, the identity of the dark lord, what defeat constitutes. At the furthest extreme, which applies to every prophecy, it is always possible that the prophecy is in some other language that, by pure coincidence, sounds like an English statement about defeating dark lord, but actually means something entirely different. > > come true no matter what if their preconditions are met and still get the opinion of an actually meaningful story? > > > I think trying to over-specify the prophecy is the wrong way to do it. Prophecies are by nature ambiguous and open to interpretation. They shift dramatic tension from "will he defeat the dark lord?" to "did I correctly guess how he will defeat him?". Meaning comes from appropriate choice of which interpretation to entertain. For example, a serious heroic epic will probably not benefit from revealing that the prophecy is about Sir John Quincy Tennyson, Lord of D'Arque County and a fellow member of the checkers club frequented by the hero. With the paradox, I think there are three ways to approach it. 1. Do not have characters actively oppose the prophecy. The hero, like the rest of the world, is not exempt from the prophecy nor its implication. If you are destined to defeat a great and powerful dark lord, it is arguably implied that you will do so by training and preparing thoroughly, rather than getting a guaranteed +9999 DMG buff for that one battle. When people in your world defeat powerful dark lords without the influence of prophecy, how do they do it? The prophecy should probably be interpreted in relation to that. 2. Lean on the ambiguities in the prophecy. For example, since it is not said when the defeat will take place, there is no guarantee that the hero will defeat him until he finishes the requisite training and preparation. If he tries to challenge the dark lord while unprepared, the result will be a non-fatal failure. The dark lord is of course free to do evil until defeated, so the longer the hero takes, the worse things get. 3. Motivate the hero with things outside the prophecy. For example, while the hero may be destined to defeat the dark lord regardless of training and preparation, what happens after? Perhaps the dark lord's second in command may want to have revenge, or to become the new dark lord, or both - and there will be no prophecy to bail you out of that fight. [Answer] If that's your universe, then the real question is what happens after he defeats the DO. Will he become another DO? Will he be bitter, angry, and vengeful? Will he be a weak leader, and let the empire fall into a hundred squabbling duchies? If a person is truly "the chosen one," then whatever system chooses him probably won't choose an unambitious slacker who is peeved at the time all of this empire building takes away from his video game playing. [Answer] ## Your prophesy might be a paradox If you prophesy "this prophesy is false", you are clearly going to have some problems. If your prophesy says "the chosen one will defeat the dark lord", but when the chosen one hears that decides there is no point fighting, your prophesy could be self defeating. ## Fortunately, the powers that be aren't stupid Whatever dictates the whims of prophesy, doesn't choose a chosen one who lets prophesy do all the work. Perhaps they know that the prophesy is true - but they don't trust it (everyone knows that the horror movie monster can't hurt them, but does that stop them being scared?). Perhaps the prophesy has some ambiguity - sure, it's basically impossible that there will ever be another seventh born of a seventh born on mount important during a blood moon while the planets align etc - but if this "chosen one" fails to do the bare minimum, perhaps in a thousand years the actual chosen one shows up. The tides of fate might also provide motivation for the chosen one. Their love interest has been captured by the dark lord, and while defeating the dark lord is certain the happily ever after is not. So they walk the path that prophesy has set for them, because doing so sooner raises their chances of rescuing their true love. But ultimately the answer is in the name - they are the chosen one, someone/something choose them for a reason. They aren't going to choose some lazy selfish non-hero. They are going to choose someone who fits the prophesy that they are making certain. ## What makes a meaningful story? Your question seems to imply that because the ending is certain, there can't be a meaningful story. But if you pick up any fantasy book, you know the farmhand is going to defeat the big bad at the end of the book (or at least at the end of the 15th 1000 page book). If you watch a rom com, you know the girl is going to get the guy in the end. The value of a story isn't the unexpected ending - if your book isn't any good until the last chapter, no one is going to read your book. The interesting parts are the journey - what challenges they face and overcome, the friends they gain (or lose), the scars they obtain and heal from, and the emotional growth of the characters on the way. [Answer] The prophecy only says that he will defeat the dark lord not how long it will take or how many lives it will cost. A better trained chosen one may defeat the dark lord earlier with less cost of life. [Answer] "Will"? *"Will"?* What kind of poxy prophecy says that The Chosen One *will* defeat the DARK OVERLORD? "Can" is proper prophecy speak. The prophecy helps you winnow out people who have a 0% chance of success, letting you save your resources for training The Chosen One. --- Caveat: there is a chance that a prophecy might say that The Chosen One will defeat the DARK OVERLORD, but that's always in the part of the prophecy to identify The Chosen One, not the part with instructions for what to do when you've found them. "Whosoever doth slay yonder OVERLORD most DARK shall be the King of this Burg", and so forth. [Answer] There isn't anything in the prophecy saying the Chosen One will survive, they will definitely defeat the dark lord but the how, why and what happens after are all a mystery. In an effort to motivate the character you could have another character explain this to them, and that by training they might actually be able to survive. Alternatively, you could have this de-motivate the character so that they will try and avoid their fate. In their attempts to escape and hide from the "Good Guys", they could be forced to learn skills that eventually help in the fated encounter. [Answer] ## There's always some degree of epistemic uncertainty It's prophesied that HERO'S NAME will defeat DARK OVERLORD. That prophecy is definitely true. There's no ontological uncertainty; what will be will be. OK, but: How do we know? 1. Is HERO'S NAME from HERO'S VILLAGE actually the correct HERO'S NAME that was referred to? 2. Did the Wise Wizard Mentors actually transcribe the prophecy correctly? Did they cook up a fake one and lie about the maths in this case? 3. Is there some sort of fishhook sentence appended to the prophecy, like '....but DARK OVERLORD'S overthrow will be merely the seed for his rebirth'? At some point, the epistemic uncertainty may become negligible, and be reduced to: 'Is this all a dream?', or even: 'Is this all an illusion, created by a Cartesian Demon?'. Regardless of how large the epistemic uncertainty is, it is likely to loom large in the mind of all involved. [Answer] I'm going to lean on Wheel of Time for my answer to this: 2 parts. Victory/Loss and Why. Prophecy depends on Victory. In the Wheel of Time, prophecy exists. The world is woven of the lives of individuals. The "lace" of ages is woven. Those with "prophecy" can "read" the pattern of various degrees. Firm prophecy (This person will be reborn and these signs will show he's the one). Deterministic (These two people will marry). Questionable (If you stay near this person? You live. Otherwise, you die). Some prophecy is easy to read and easy to interpret. Most is questionable. Just because it's said you'll marry that person? It's prophesied that you'll be attacked? That's not when. Not attacked by who. etc. But there's a catch... that prophecy is a reading of the current "pattern". The current and future of the weave being woven. If the "Dark One" wins? He rewrites the playbook. So all the prophecies of next year? You're going to be crowned king and you're going to marry the princess? Your kids will be legends? If the Dark One wins? Those above prophecies are useless because the DO will then control the lace and his plans are going to be different. Why? Part 2 is why. Why fight? I'm a soldier. You're a soldier. we both fight for the Queen. I fight for money. You fight to protect your family and loved ones. We are both sworn. We both die. Is there a difference? Absolutely. The why makes all the difference. Fate controls us. We go where the Queen says and we die at her command. But we do so for different reasons and, as humans, that reason makes all the difference. You can go to the "Last Battle" with the "Dark One" and fight... and win. But if your reasons are dark? What will the result be? If you use dark methods, will your victory be any different from the DOs? Will it be a victory of the light? or simply a victory of a different kind of evil? The WHY of why you fight is massive and shouldn't be discounted. That why determines everything before, during and after - and discovery of the importance of fighting for love instead of money is its own battle, fight and victory. [Answer] # Change the prophecy just a little Instead of: > > The Chosen One will defeat the DARK OVERLORD > > > Say: > > The Chosen One will be able to defeat the DARK OVERLORD > > > Or: > > Whether the DARK OVERLORD will rule or be defeated will depend on The Chosen One > > > Or something like that. Then the Chosen One will have to try. Otherwise the DARK OVERLORD prevails and it will be because of the inaction of the Chosen One. It could make the story a bit more interesting because now the Dark Overlord, knowing about the prophecy, may try to bargain with the Chosen One, may try to convince the Chosen One to abandon the quest to overthrow the DARK OVERLORD. Because convincing and/or manipulating the Chosen One will be the only, although quite realistic chance for the Dark Overlord to not be defeated. ## Alternatively If you keep the prophecy at it's current form (that is, "the Chosen One will defeat the DARK OVERLORD") then, effectively, you end up with the concept of Fate. This leads to the realm of Greek tragedies. Read, for example, the history of Oedipus. Everyone was doing their best to avert the prophecy but, instead, it was fulfilled anyway. So it could be an interesting twist to your story: The Chosen One worships the DARK OVERLORD, accepts the tyrannical rule of the DARK OVERLORD, fights for the cause of the DARK OVERLORD but ends up defeating the DARK OVERLORD anyway. ]
[Question] [ I know language is not easy to learn, so I have a little bit strange idea: would a civilization simpify their language just because it is too difficult to learn? For example, to simplify English: 1. Disable some words with same meaning, eg:disclose, reveal, uncover -> just use 'reveal' 2. Unify past tense: append 'ed' to verbs,eg: past tense of 'go' become 'goed' 3. Reduce the length of some words, eg: elephant -> elept Would a civilization simplify their own language in order to: 1. Let the students learn more quickly 2. Let elderly with lower educational level also able to learn the language 3. Visitors would more willing to learn their language Is it practical? [Answer] > > I know language is not easy to learn, so I have a little bit strange > idea: would a civilization simpify their language just because it is > too difficult to learn?/ > > > I am surprised that there are so many answers stating that is impossible and has never been tried. The best example is the reform of Turkish. <http://countrystudies.us/turkey/25.htm> > > With the establishment of the republic, Atatürk made language reform > an important part of the nationalist program. The goal was to produce > a language that was more Turkish and less Arabic, Persian, and > Islamic; one that was more modern, practical, and precise, and less > difficult to learn. The republican language reform called for a > drastic alteration of both the spoken and the written language. This > process was to be accomplished through two basic strategies--adoption > of a new alphabet and purification of the vocabulary. > > > Many goals at once: simplification, modernization, elimination of foreign words, moving towards a more western feel for the language. You read most about the switch of alphabets (Arabic to Latin) but there was also a lot of change in the words themselves. I understand that because Turkish is now phonetic it is easy for kids to learn to write. This is exactly the sort of thing the OP was asking about. Other examples This re the creation of the Hangul alphabet for Korean. <https://en.wikipedia.org/wiki/Korean_language#Differences_between_North_Korean_and_South_Korean> > > However, due to the fundamental differences between the Korean and > Chinese languages, and the large number of characters needed to be > learned, there was much difficulty in learning how to write using > Chinese characters for the lower classes, who often didn't have the > privilege of education. To assuage this problem, King Sejong created > the unique alphabet known as Hangul to promote literacy among the > common people. Hangul was denounced and looked down upon by the > yangban aristocracy who deemed it too easy to learn, but it > gained widespread use among the common class, and was widely used > to print popular novels which were enjoyed by the common class. > > > Too easy to learn! I have read that once Korean kids can speak, it takes them about a week to learn the characters and they can then read and write. How cool would that be? This as regards the standardization of Haitian Creole > > <https://en.wikipedia.org/wiki/Haitian_Creole> Before Haitian Creole > orthography was standardized in the late 20th century, spelling > varied, but was based on subjecting spoken Haitian Creole to written > French, a language whose spelling has not matched its pronunciation > since at least the 16th century. Unlike the phonetic orthography, > French orthography of Haitian Creole is not standardized and varies > according to the writer; some use exact French spelling, others adjust > the spelling of certain words to represent pronunciation of the > cognate in Haitian Creole, removing the silent letters. > > > Before this, education in Haiti was done in French, a language many kids did not speak. ! These endeavors have in common an interest in education and also nationalist / political interests. [Answer] In short, it would not work. There already has been attempts at artificial languages, like [Esperanto](https://en.wikipedia.org/wiki/Esperanto) with the same goals and ambitions. There is a reason why languages are complicated. Language is the way we humans symbolically represent reality and express thought. As thought and reality changes so does language. [Language shapes](https://en.wikipedia.org/wiki/Linguistic_relativity) the speakers and the speakers [shape the language](https://www.merriam-webster.com/words-at-play/new-words-in-the-dictionary-feb-2017). Look at [pidgin](https://en.wikipedia.org/wiki/Pidgin) and [creole](https://en.wikipedia.org/wiki/Creole_language) language forming naturally when two people groups with disparate languages come together. IF you have a politically powerful government who was willing and able to enforce languages (i.e. monitor language like Big Brother in Nineteen Eighty-four) or remove children from the home, it could be done. However, the simplification would be undone quickly, and the new simple language would evolve to fit the complexity of human thought. Edit: My comments are directed towards spoken language. It is much easier to change a system of writing (Korean alphabet, simplified Chinese, cursive and print English) than the day-to-day language that is taught and used in a home. My comments answered the original question, can a government, with the motivation of making a language easier to learn, modify the spoken language by removing words. The example of the creation of modern Turkish, motivated by nationalistic pride, as been cited as an example of why I am wrong. The change was not made to simplify Turkish, but to make it "more pure" and less reliant upon words borrowed from other languages. The people, motivated by nationalism and civic pride, had reasons to modify their own speech patterns. And the language that is spoken there today, nearly 100 years later, will have evolved and changed over time. [Answer] A language might be simplified when literacy is not as high as people would like. (That's not a sufficient condition, but it can be a driver.) We see this with [simplified Chinese](https://en.wikipedia.org/wiki/Simplified_Chinese_characters), which started in the early 20th century for use in education. The government of China has promoted simplified Chinese since the 1950s as a way to increase literacy. My Chinese coworkers (living in the US) read and write both traditional and simplified Chinese. This isn't exactly analogous to what you're describing; Simplified vs. Traditional Chinese is a difference in how the language is written but not in the grammar itself. (The spoken language is the same.) But, from what I understand (I do not know Chinese myself), Chinese doesn't have the kinds of grammatical markers that English does; there's no equivalent to the "-ed means past tense" rule, for instance. You get tense, number, possessiveness, etc. from the way hundreds of characters are composed. What they did to try to improve literacy was to make those hundreds of characters easier to read and write. That seems similar in spirit to your idea of making English easier to understand by reducing the complexity of its grammar; instead of hundreds of complex characters you're simplifying dozens (?) of complex rules. It's an analogy, not a direct example. I doubt that a population that is already largely literate and fluent would see a need to simplify its language. And you probably couldn't simplify all English anywhere, in the same way that simplified Chinese didn't take over in all Chinese-speaking places. But in a population with lower literacy and a government able to enforce a change (for whatever reasons), it seems plausible that simplification efforts could succeed. [Answer] Would a civilisation try to? Yes, and they continue to do so now (I'm looking at you Académie française). Does it achieve any of the goals you stated? Nope, not a one. There is an argument that the primary function of language is cognitive, rather than communicative. It is a system of abstract thought in which we apply a finite set of combinatorial rules (~syntax) to a finite set of meaningful symbols (~words) in order to produce an infinite set of possible complex meanings. Serendipitously, we can also use this system to communicate with one another. We're fully equipped with the hardware, and by extension, the fundamentals of linguistic architecture from birth. All we are required to learn is the arbitrary set of rules and symbols our native language is comprised of. Just as a child will learn to crawl and walk, (barring developmental disorder or a catastrophic lack of input), a child will acquire language. It is fundamentally human. Compare this with other learnt behaviours, like playing the guitar, which many people cannot do (even with hundreds of hours worth of lessons; sorry Mum). All humans are highly competent in their native language(s). Often, when we make judgements about others' lack of linguistic skills, we are merely judging their particular dialect(s) as being inferior, which is more a judgement of aesthetics, rather than complexity. What you are proposing doesn't really make the language any easier. More regular, perhaps, but not really any easier. The really hard parts of language are largely invisible to us, precisely because we are so good at it! It's possible that it would make the language easier to learn as a second language, but even then, that would be largely dependent people's first language, and how dissimilar it was in terms of phonology, morphology, syntax, etc. And lastly, many many authorities have tried and failed to make speakers conform to an idealised form of whatever language. It doesn't work. Governments and institutions can lend prestige to particular usages of language, but ultimately, whatever they dictate ends up being just one in many considerations a speaker makes when considering what to say and how to say it. [Answer] Look at your own examples: * disclose: Tell others about something you know. It might or might not be new to you. Sounds a bit official, as in "full disclosure." * reveal: Tell others about something you know. It might or might not be new to you. Sounds a bit like a surprise, as in "the revelation at the end of the novel." * uncover: Find something that had been new to you. You might or might not communicate it. "I finally uncovered the facts of the case." There is a famous novel where the English language was [reduced](https://en.wikipedia.org/wiki/Newspeak) to prevent disloyal thoughts by the population. It would have prevented critical thinking as well ... [Answer] I don't know about removing words per se, but as someone who is trying to teach his kids to read, I'd start by simplifying the alphabet and spelling rules. For instance, get rid of the letter C, and just use the letter K or the letter S. I don't know how often I've had to klarify a word. "No, certain is an S sound." "Cat is a K sound." etc. An exseption might be CH, which would be like QU. G would have to undergo an overhaul, with some changed to J. Words like Great staying the same, while Giant would be changed to Jiant. We'd finally be able to settle the Gif debate for good. Hard and soft vowels would need to be fixed in some words. For example, Have has a problem, and so the E should be left off. Live and Liv would be readable at a glans. If we're goeing to be telling kids that an E at the end of a word makes the vowel say it's name, it should be konsistent. Wee'd finally bee able to fix Weird, since it doesn't follow the I before E rule, which is just wierd. Som of the borrowed foreign words should be fixed too. Resume could be fixed by changeing it to Resumay for instance, and would be different from resume. These ar just a few of the offending examples of how words hav broken over time, and I think wee should really giv the whole system an overhaul. I'll finish with the klassik joke (based on one made by Mark Twain): > > The European Commission has just announced an agreement whereby English will be the official language of the European Union rather than German, which was the other possibility. > > > As part of the negotiations, the British Government conceded that English spelling had some room for improvement and has accepted a 5- year phase-in plan that would become known as "Euro-English". > > > In the first year, "s" will replace the soft "c". Sertainly, this will make the sivil servants jump with joy. The hard "c" will be dropped in favour of "k". This should klear up konfusion, and keyboards kan have one less letter. There will be growing publik enthusiasm in the sekond year when the troublesome "ph" will be replaced with "f". This will make words like fotograf 20% shorter. > > > In the 3rd year, publik akseptanse of the new spelling kan be expekted to reach the stage where more komplikated changes are possible. Governments will enkourage the removal of double letters which have always ben a deterent to akurate speling. Also, al wil agre that the horibl mes of the silent "e" in the languag is disgrasful and it should go away. > > > By the 4th yer people wil be reseptiv to steps such as replasing "th" with "z" and "w" with "v". > > > During ze fifz yer, ze unesesary "o" kan be dropd from vords kontaining "ou" and after ziz fifz yer, ve vil hav a reil sensibl riten styl. Zer vil be no mor trubl or difikultis and evrivun vil find it ezi tu understand ech oza. Ze drem of a united urop vil finali kum tru. > > > Und efter ze fifz yer, ve vil al be speking German like zey vunted in ze forst plas. > > > Edit: Found the version attributed to Mark Twain: > > For example, in Year 1 that useless letter "c" would be dropped to be replased either by "k" or "s", and likewise "x" would no longer be part of the alphabet. > > > The only kase in which "c" would be retained would be the "ch" formation, which will be dealt with later. > > > Year 2 might reform "w" spelling, so that "which" and "one" would take the same konsonant, wile Year 3 might well abolish "y" replasing it with "i" and iear 4 might fiks the "g/j" anomali wonse and for all. > > > Jenerally, then, the improvement would kontinue iear bai iear with iear 5 doing awai with useless double konsonants, and iears 6-12 or so modifaiing vowlz and the rimeining voist and unvoist konsonants. > > > Bai iear 15 or sou, it wud fainali bi posibl tu meik ius ov thi ridandant letez "c", "y" and "x" -- bai now jast a memori in the maindz ov ould doderez -- tu riplais "ch", "sh", and "th" rispektivli. > > > Fainali, xen, aafte sam 20 iers ov orxogrefkl riform, wi wud hev a lojikl, kohirnt speling in ius xrewawt xe Ingliy-spiking werld. > > > Here is another, more serious artikle hee wrote: [A Simplified Alphabet](http://www.online-literature.com/twain/1322/) [Answer] It can change, it does change and it should change for that very reason. The fact that you ask this question simply says that it changes so slowly that you haven't noticed it in your lifetime. --- ## Lets look at some common objections: We tried engineered languages and they didn't get wide adoption. True, but they didn't work because you asked people to learn a whole new language instead of gradually changing their own. Languages are inherently evolutionary systems. True and they will continue to be. I'm not saying we should prevent languages from mutating naturally. But evolutionary systems tend to jump from one local extrema to the next. Over time this leaves a lot of useless and unnecessary peculiarities. There is no harm in trimming those. There is no central authority that defines a language. False. For languages that are official for only one country, there usually is a government body (the ministry/academy of education or equivalent) which describes what is proper grammar and vocabulary. It is the case even for some languages spoken in multiple countries. For example, Spanish has [Real Academia Española](https://en.wikipedia.org/wiki/Real_Academia_Espa%C3%B1ola). Granted, for historical and cultural reasons, English is a bit more of a special case. Still, you can say that there are multiple authorities on it. Think about it - you do have public school English textbooks. Someone has to define what should and shouldn't go there. So in a sense there are central authorities for British English, American English, Indian English and so on. Most people would also agree that the Oxford dictionary defines the English vocabulary. If you don't, I'm interested in how use to settle your scrabble disputes! Me red hole Okford diktiounery, yo. Dere no "swag" 'n stuf dere, yo! Sure. There are slangs, jargon and dialects. As time passes the authority may or may not include them depending on usage and other factors. This doesn't mean that the canonical form of the language doesn't exist or that it isn't defined by said authority. Kids are amazing at learning languages and once you are an adult, you no longer have problems with your native language. So it's a non-issue. Kids are indeed outstanding considering that all we do to help them start is point at objects and make sounds over and over again. They still make a ton of (what we consider) silly mistakes both in speaking and writing. Imagine if 10% of that learning potential was focused at something else as early as possible. As for adults - just ask a person with degree in philology. Also misunderstandings happen all the time with roots in language. --- ## So what are the actual issues preventing the constant change of languages? The main problem is the cost of the change. New textbooks have to be printed. The public has to be informed and adoption takes time. Old documents have to be revisited or rules to interpret their meaning has to be defined. There are other case specific costs. For example if we decide to add/remove/change a letter in the English alphabet it will be a tremendous challenge in the digital age. Every related standard and implementation, be it character tables, fonts, operational systems, programming languages, hardware like typewriters and keyboards and what not will have to change as well. The cost of migration after a non-backwards compatible change is a well understood pain in software engineering. Different schools of thought exist on how much and how often is acceptable to introduce such changes depending on context. I could write pages on it, the gist of it is that we have well tried strategies to assess if it's worth doing and ways to mitigate said cost. And my ¢2 is that we should do it more often and in greater quantities than we do today for the natural languages I'm knowledgeable in. The other problem is social. Paradoxically, most people don't consider their language simply a communication tool. They see it as part of their identity. To change it is to strip pieces of their identity and to acknowledge that there was something wrong with it in the first place. Some go as far as to call the language sacred. Perfect. Immutable. As this is worldbuilding SE, I propose that you simply change the culture around it. Lets say that every day you cross the same intersection. As you are waiting for your turn as usual, you get an epiphany. What if instead of how it is now, the periodically of this traffic light is changed in this specific way? Both ways will have to wait less and there is no other consideration that you can think of. You go home in the evening and you remember what you thought earlier. You are filled with curiosity and excitement. There has to be a reason why it is as it is. Right? It haunts your mind until you finally decide to write an email/snail mail/whatever to the authorities. A month later you get a reply. "We looked at your suggestion and you are in fact correct. This will be implemented by [date-here]." You feel proud. It's not a Nobel price, but you did use your intellect to slightly improve something people use every day. You did your civic duty. You saw something that dedicated professionals missed. You tell all your friends in casual conversations about it. They are mildly impressed and give you kudos. What if we had the same attitude towards language? What if there were government appointed linguists that strive to make that language the simplest most expressive, consistent and unambiguous form of communication there is? After the low hanging fruits are dealt with, it will be incredibly hard to find a way to simplify some grammar rule without negative consequences. One day you could find such simplification and submit it to the linguists. If after inspection they agree with you, your name could, for example, be mentioned in the news where the change was briefly announced. O frabjous day! Callooh! Callay! I'm genuinely interested to read a piece of fiction where character dialog is in "perfectionalized" English, while the rest of the book is in "pain" English. But I digress... --- A quick note - I don't see removal of synonyms as an improvement in the above terms. Most of the time they have slight nuances. So you would be reducing expressiveness. Making irregular verbs regular is a better example. [Answer] Things you pointed as examples are unlikely. But such reforms are real. <https://en.wikipedia.org/wiki/Language_reform#Examples> But more often it boils down to this: <https://en.wikipedia.org/wiki/Spelling_reform> I should point out that it is mostly aimed at simplifying grammar, often leaving phronouncements untouched, exactly because of practical approach. All in all, i think, it depends on the communication technology level and government type. Tyranical governments can easily do (and did) it at a whim, but if they lack capability (due to medieval setting, or lack of FTL in sci-fi setting) to spread and reinforce such reform, new laws will be as good as splat of ink on paper. More democratic govements are likely to meet enormous counterforce to their reforms in the face of their entire population, who are unlikely to enjoy re-learning half of dictionary for the benefit of "outsiders". Also worth mentioning that it worked better in past because of tiny amounts of educated people it affected. Nowadays and in the future, the bigger the percentage of educated people, the lesser the chance of this happening. [Answer] You don't see governments attempting to do this because it's really not their place. Linguists know the truth about languages: there are no rules. Nobody set the rules for how we speak. We spoke, let it evolve, and after the fact we tried to figure out what rules our brains might have been using. The purpose of language is communication. Generally speaking they are constantly evolving to maximize communication, so any attempt to manually adjust the rules must, by definition, hurt. Instead, you simply let the language evolve. One example of this happening is lower class dialects. In many places, the lower class speak a dialect which is easier to learn and use. Only the high class speak the "proper" language, and I put that in scare-quotes for a very good reason. In English, I find the most obvious version of this appears in the English spoken by Chinese immigrants. The English language is very hard for a Chinese speaker because all of the phonemes are different. Their ear is literally trained to hear things differently. There's also the complicated issues such as articles and plurals which are not found in the Chinese language. Thus, when you hear a Chinese immigrant speak, many of them speak a simplified English that doesn't have these nuances. No surprise, there's a general trend to treat these people as a lower class, but they do succeed in communicating with this simplified English. I wouldn't say it's their fault, but it is what it is. Another interesting example of the language simplifying itself is in Chinese. In the younger generations, texting is very popular. However, texting in proper Hanzi characters is difficult on the input devices of today. Accordingly, many young Chinese are using pinyin, the romanized version of all of the words (instead of writing "气" you would write "qì"). This is slowly shaping their language. There's many homophones in Chinese. In speech, you have the context of the conversation to help disambiguate them and you can ask questions. In Chinese writing, the symbols represent the words, not the sounds, so there's no confusion. However, this new generation is using pinyin, which is phonetic. This is shaping the language, changing word choices and such to deal with these homophones, and what to do with the youngsters which no longer have as much of a need to memorize the same number of symbols as they used to. The Chinese government who "controls" the language, is actually in the process of trying to figure out what to do about this new shift. Obviously the traditionalists feel that the youngsters are destroying the language, but you can never destroy a language. It merely shifts. [Answer] Languages naturally and somewhat inevitably continually change and modify themselves over time. Usually this involves simplifying those languages and dropping exceptions. English is full of exceptions. For example, 'contemptible' and not 'contemptable'. As the OP suggested all past tense verbs could be affixed with "ed". Changes of this sort can be witnessed in confusion between simple words such as "it's" and "its" where "it's" is the contraction of the phrase "it is" and "its" is possessive of something belonging to a thing (not a person either female or male). The use of apostrophes is changing. Once "Tom's book" would have been correct, but now "Toms book" is correct for the possessive form of the book belonging to Tom. Persons with old brains would think "Toms" was the plural form of Tom (i.e., there was more than one Tom related to the book). This is in a transitional phase. Both usages are correct. Useful guidance can be in this [style guide](http://www.editoraustralia.com/styleguide_apostrophes.html) about the use of the apostrophe. This discussion about the [apostrophes](https://brians.wsu.edu/2016/05/17/apostrophes/) as a common error provides background to the issues about the use and misuse of the apostrophe. A search has been unable to locate an online source for the dropping of the apostrophe from possessives. This author has actually sighted the text of a style guide that proposed dropping the apostrophe from possessive words, thereby making them indistinguishable from plurals. Languages are continually changing. Usually those changes will simplify the language. Indeed languages in their earliest forms have remarkably precise word usages and often have elaborate and complicated grammars. There have been a variety of artificial languages and spelling reform campaigns to both streamline language usage and make them easier to learn and acquire. The most successful example of language reform is Simplified Chinese. This was government mandated, because reforms of this kind require the highest level of authority. Side-note: Members of the Chinese diaspora who have grown up with Traditional Chinese often detest Simplified Chinese. It would be interesting to compare their opinions with Mainland Chinese who were inculcated with Simpler version from birth. Language change over time tends to simplify and adopt systematic forms for word usage. It is unlikely that governments will be instigating major language reforms any time soon. [Answer] The concept of reducing the scope of language pretends to solve the learning experience; however, it implies drastic disadvantages towards the intellectual development of its native speakers. The acclaimed language philosopher Ludwig Wittgenstein states that “The limits of my language means the limits of my world.”. This bold statement reflects the importance of having a rich vocabulary, which should exist in every language. A classic supporting reference to the idea of the danger of limiting language is Orwell's Nineteen Eighty-four, as Andrew Neely pointed out. This is clearly show on the quote: > > “Don't you see that the whole aim of Newspeak is to narrow the range of thought? In the end we shall make thought-crime literally impossible, because there will be no words in which to express it. Every concept that can ever be needed will be expressed by exactly one word, with its meaning rigidly defined and all its subsidiary meanings rubbed out and forgotten. . . . The process will still be continuing long after you and I are dead. Every year fewer and fewer words, and the range of consciousness always a little smaller. Even now, of course, there's no reason or excuse for committing thought-crime. It's merely a question of self-discipline, reality-control. But in the end there won't be any need even for that. . . . Has it ever occurred to you, Winston, that by the year 2050, at the very latest, not a single human being will be alive who could understand such a conversation as we are having now?” > > > As a final answer, only an inattentive civilization would simplify their language in order to ease the learning process. Learning a complex language is hard, but it is definitely worth it. [Answer] Simplifications of vocabulary have been tried. Basic English is an example. The trouble is, it may make the language easier to learn but it robs it of expressiveness. That is okay in an auxiliary language, but only there. Simplification of accidence (as in went/goed) is a lot less useful than beginners think. It happens of its own accord, but generally at a glacial pace. English once had the distinction between ye (nominative) and you (accusative), as in ye go but I see you. You'll see it in Shakespeare, but it was probably old-fashioned even in his day. It's gone now, and studying Shakespeare at school is the only reason people even know about it today. Language reform usually means only spelling or writing-system reform. It normally has political rather than linguistic goals. And it is the only kind of direct language reform open to governments, because they can insist that it is taught in schools, and printed in schoolbooks, and that civil servants write letters in it. They can't legislate how people talk or what they say on Facebook. One example of this is Turkish, where a the state substituted the roman alphabet for arabic script with the explicit intention of making old documents inaccessible. Another is Dutch, where the postwar spelling reform, however attractive to its political sponsors, was a linguistic disaster. One result is that Dutch is the only speech community I know of where adults compete on TV in annual nationally-organized events to take dictation with the fewest spelling errors. Such a thing would be unthinkable in an English-language speech community, despite English's allegedly unworkable spelling. In Korea it appears that the languages north and south of the DMZ are diverging in vocabulary because words that were once common to both have fallen out of use, or have acquired different meanings or connotations, in one speech community or the other, as a result of political attitudes. But this not a result of deliberate language reform; rather, some words, or rather concepts, have become be politically incorrect. This is not a minor issue: lexicographers are now beginning to doubt if it is possible to produce one dictionary that will serve both speech communities. You see the same effect in English. When I was a child, people were considered male or female and that was called their sex. If you learnt French or Latin or German, you were taught that all nouns had a gender (not male nor female, but masculine, feminine or neuter), which then was a purely grammatical category, so in German the word das Mädchen 'the girl' had neuter gender but its referent had female sex. Today, of course, you say that a person's gender is male, female or other, and nobody is taught grammar anymore so the distinction between sex and gender no longer matters. So, politics can influence language, but (apart from spelling) only indirectly. Direct interventions fail. In 1960 South Africa decimalized its currency and declared that the plural of the new currency, Rand, would be uninflected. Despite having total control of broadcasting and primary and secondary education, the state couldn't make it stick. English-speaking South Africans very frequently talk about Rands. Even on the radio. Similarly, the efforts of the European Commission to declare that the plural of euro shall be euro in all languages have failed. The rule was devised by largely French- and German-speaking accountants with a tin ear for language. What they wanted to avoid was having the same word with a dozen different inflections on the banknotes, something that famously disfigured USSR money. That was reasonable. But they went beyond their remit and tried to tell speakers of other languages how to talk. Most English speakers say ten euros, just as they would say ten dollars or ten pounds. You can say ten pound and be understood, but that marks you as a speaker of a regional dialect. Informally, Dutch people often say euri (a common way to pluralize borrowed words in -o) and in Irish and Hungarian the word gets inflected according to the rules of the language, not the rules of the Eurocrats. But social initiatives can work. About 35 years ago the Dutch decided to abolish the distinction between mevrouw 'Mrs' and mejuffrouw 'Miss'. That has been so successful that mejuffrouw, for all practical purposes, no longer exists. (A similar initiative in France has failed, so far.) Some Swedes have been trying for 50 years to introduce hen as a sex-neutral personal pronoun to supplant hon 'she' and han 'he'. Who knows, this time around it may stick. The Dutch are playing with hen 'them' as a sex-neutral pronoun for people who don't want to be referred to as hij 'he' or zij 'she'. But if it does work, that is because people adopt it in response to changed social or political attitudes, not because some language commission or academy says it's correct. [Answer] You may be interested in the [Simple English Wikipedia](https://simple.wikipedia.org/wiki/Main_Page) which is written in this simplified kind of language. Other kinds of simplified English are listed [here](https://en.wikipedia.org/wiki/Simple_English). These forms of English are much easier to understand for non-native speakers and can also help reduce ambiguity in translation. They are useful in their context. One can imagine a civilization where the official "prestige" style for communications is this sort of simplified language. I don't think it's as well-established as some people are claiming that language shapes thought and culture. But it certainly reflects it. As soon as people had a need for more complicated gradations in vocabulary the language would start to grow more complex. Not to mention technical jargon. I do not think that people would put up with such artificial simplicity in the real world. [Answer] Classical Greek was simplified into Koiné when Alexander the Great spread its culture across Asia Minor and beyond. The language the New Testament is written in is vastly simpler than the language of Athens (or other dialects) used in classic times. In a similar vein, Latin was watered down when it became the language of an empire: post-classic Latin is a lot simpler than what the language started with. In contrast, it is a bit surprising how little the Castilian and Portuguese carried into the Americas was watered down there. [Answer] > > * Disable some words with same meaning, eg:disclose, reveal, uncover -> just use 'reveal' > > > No. Diverse vocabularies are necessary in many if not all fields. A language reform that creates such immense ambiguity would be rejected vehemently by it's users. > > * Unify past tense: append 'ed' to verbs,eg: past tense of 'go' become 'goed' > > > Possibly. Much of a language's usage is what you could call an acquired taste. You have learned to say "go" and have used it for years if not decades. Also "go" is an extremely common verb, so learning it's strange variations is "worth" the effort. This is why uncommon verbs are far more regular. Now if all common verbs were like this (drive -> brok, sleep -> tess, eat -> lart, ...) then a simplification reform might be reasonable. > > * Reduce the length of some words, eg: elephant -> elept > > > Nope. There's very little benefit and a significant cost to such a change. If you went on the street and asked people what they thought an "elept" to be, you'd probably get a decent selection of answers. Now if you asked them what an "elefant" would be, things would look differently. Such simplification are often proposed in actual language reforms. German had a ton of those: notably pretty much all words containing ph were moved to f (Telephon -> Telefon). There was resistance but the move is essentially complete. If the move is obvious and makes things easier it has a chance. Similarly other idiosyncrasies were removed (ie. the German word for Chamois which had a switch from e in singular to a in plural is now using a for both forms). This again had resistance in the beginning but is largely a done deal by now. Continuing with the German Language Reform as an example, there were many relatively small tweaks that went over really well because: 1. they did make things simple for a lot of situations 2. kept the accuracy of the language intact 3. and people didn't really care one way or another Example: When combining words where one word ends with the same letter as the next one starts with. Now all letters are written where there used to be cases where sequences of three identical consonants would be shortened to just two. Other changes were much more fought over. In some cases the language as taught by teachers ended up displacing the old form over time. In other cases there is still strong opposition with many notable publications and users favoring the old form or a compromise. Example: The old German used to have a difference between: * "to come together" (as in meeting): zusammenkommen * and "to come together" (simultaneously climax) zusammen kommen The reform was supposed to move both meanings to the second form, which was and still is strongly opposed. TL/DR: Yes, reforms are a thing IRL and actually not uncommon. Success depends greatly on: * ease of transition * simplification over "dumbing down" * benefits vs cost for the user/learner [Answer] In a way, this has already happened, to English, of all languages. If I recall correctly, Old English was about as complicated as German and Russian today, with all sorts of strict rules for conjugation, among other things. After a series of invasions and cultural mergings, however, English grammar had become greatly simplified. To this day, I'm amazed at how simple English conjugation is, compared to French, German, or Russian. But this "simplification" came at a cost: English has an insane number of exceptions to every rule. Indeed, it is my understanding that the best way to understand "i before e" in spelling, is to know the origin of the word. English has a nasty habit of maintaining the spelling of foreign words, even when the pronunciation of that word no longer makes sense. And English has another nasty habit of not just borrowing words from other languages -- they follow other languages down dark alleys, mug them, and then ruffle their pockets for spare words. As others have mentioned, being able to communicate with people from the past is also important. For a little while, I was trying to create a simplified alphabet. My efforts were deflated, though, when I realized that if I succeeded in simplifying the alphabet, people wouldn't be able to read my adviser's works -- and since he is a mathematician, that means that his work may even provide a needed breakthrough in unexpected ways! I later learned that China's efforts to simplify how Chinese was written has also meant their population can no longer read some of the older works of their culture. So, yes, it's possible, and it isn't necessarily done consciously, but there can be nasty side effects as well. [Answer] Chinese language is simplified twice in recent 100 years. The first wave is to turn written form from classical Chinese (there is even no punctuation in it! Consider the difficulty and ambiguity you have to face when you read it) to modern Chinese (colloquialism?) led by activists. The second wave is to simplify Chinese characters which is led by the government. And it is practical. These changes make learning, reading, writing Chinese much easier. And Japanese language is also simplified in recent 100 years by reducing the use of unnecessary Chinese characters which helps everyone learn it. [Answer] In English, many some irregular verbs become regular. More chances for those words which is used relatively rare. So `went` almost never become `goed` while `learnt` could be written as `learned`. That's what I learnt when I learned irregular English verbs ;) The trick is you must to know only limited set of irregular verbs. Even when I use `blowed` instead `blew` I may expect that people understand me. Another example is changing gender of `cofee` in Russian. First `кофе` was strictly 'he' and later 'it' become more and more popular. --- Any spoken language is live, and not-used are commonly called dead. Any live organism is developing. It reduces useless forms and creates new where needed. Most dictionaries just describe (or reflect) the current situation, but not set new rules. There are exceptions which you could find in another answers. [Answer] > > I know language is not easy to learn, > > > Stop right there. Language is easy to learn. Children do it as easy as breathing. Kids can even learn multiple languages at once without breaking a sweat. It is just when we become adults it becomes hard. A simpler language makes for a simpler, less capable mind. We really don't want to do that to our children. Your only valid point is > > Visitors would more willing to learn their language > > > Yes, adult visitors have problems, and a simplified language will help them... but is it worth the price? I don't think so. [Answer] One practical example of rule 1 in the question is the use of a controlled language. [Simplified Technical English](https://en.wikipedia.org/wiki/Simplified_Technical_English) is one example. Simplified Technical English was [designed](http://asd-ste100.org/) for use in the aerospace industry (specifically, for maintenance manuals). STE is a set of [rules](http://asd-ste100.org/request.html): * there's a list of allowed and forbidden words, designed to make all allowed words unambiguous. * there's a set of writing rules that are designed to make texts easy to understand. Sentences should use a simple structure, for example. No subclauses (or phrases between brackets), etc. STE is a subset of English: it doesn't invent new words or new grammar. You can get spelling/grammar checkers for STE (there's a free plugin for Notepad++, IIRC). STE is limited: its word list is geared towards the aerospace industry and would be inadequate for e.g. legal texts. [Answer] I am shocked at how many clearly false answers have already been posted stating that this is impossible. It obviously isn't impossible, as it has already been successful many times throughout history. --- My favourite such example is [Hangul](https://en.wikipedia.org/wiki/Hangul), the alphabet used across Korea since the 15th century. Prior to Hangul Koreans were writing with Chinese symbols, however the Chinese symbols were extremely difficult to learn as a Korean-speaker because they didn't fit the Korean language intuitively at all. [![Korean](https://i.stack.imgur.com/v5jQ0.png)](https://i.stack.imgur.com/v5jQ0.png) The language-loving YouTuber Xidnaf does a great job of explaining the origins of this language in [his YouTube video on the topic](https://www.youtube.com/watch?v=K53oCDZPPiw), which I don't think I can beat, so I'm going to quote some his commentary explaining how this incredible language came to be: > > Not too many people could read and write Korean before Hangul. > > > Mostly, it was just upper class academics who could read and write, and most of these academics didn't particularly mind all of the pre-Hangul insanity, because they wanted to be more like China, which, for them, was a symbol of refinement and civilization. > > > So, who eventually did come along to propose something different? None other than the king himself, Sejong the Great. Sejong was king of Korea during the early 1400s, and he was one of Korea's coolest kings, and not just because he personally invented Hangul. > > > For one thing, he was a hardcore Confucianist. He believed > that it was his duty to use his power to benefit the people as best he could, and one of the major things he did was to begin appointing people to government positions based on their merit, without regard to class or wealth. > > > But one of the biggest confucian principals he > believed in was that everyone should seek to improve themselves by studying and learning. > > > So, not surprisingly, he was rather deeply disturbed by the fact that almost no one in his entire kingdom could read or write, and he didn't blame this on his people either. > > > He knew how insanely hard the current system was. He himself actually said at one point that trying to use Chinese characters for Korean was "like trying to fit a square handle > into a round hole." > > > Because one of his main goals was to make a system that was really easy to learn, he wound up creating probably the simplest, easiest writing system in the world. > > > [![Sejong the Great wound up creating probably the simplest, easiest writing system in the world](https://i.stack.imgur.com/jTUmY.jpg)](https://i.stack.imgur.com/jTUmY.jpg) > > > Seriously, if I were trying to teach you this system in this video, I would probably mostly done by now. I'll post a [link to a short comic](https://9gag.com/gag/3968335) in the description that claims to be able to teach it to you in 15 minutes, but I actually think that that's a bit high. Seriously, just read the comic through and you’ll be able to read and write Hangul by the end of it. > > > Because it was so easy to tell how things were pronounced based on how the symbols looked, this system spread all across Korea like wildfire after Sejong invented it. > > > Sejong said of these symbols that "A wise man can > acquaint himself with them before the morning is over; a stupid man can learn them in the space of ten days." And he was right. In fact, it was so effective at educating the population, that latter kings tried to abolish it because they thought it was making people too smart. > > > The Korean writing system, designed purposefully to be easy and fast to learn, was completely successful, as is proved by its continued use today some half-a-millenia later. [Answer] If the official language was different from the language(s) of the common people, one might create a pidgin language. A pidgin takes things from the languages of the people trying to communicate, sticks them together, and simplifies as much as possible. In this case, the vocabulary would probably be based on the official language, but the grammar would probably be different (more related to the commoners' language(s)). The sounds (phonology) would have to be simplified. Take the sounds of the dominant language, then take away all the sounds that don't exist in the commoners' language. For example, "s", "sh", and "j" might all become "s". The grammar would be simplified a lot -- simple structure, no irregular verbs, that sort of thing. The number of words would be much lower than in a normal language. The pidgin language would be easier to learn for the commoners, and if they ever wanted (or were allowed) to master the "real" official language, they'd have a head start. The elite would probably still speak the original official language, since it sets them apart from the lower classes. For extra fun, if people use the pidgin language regularly enough, people's kids will start to learn it. Once a group of children learn to speak a pidgin, the pidgin ends up as complex as any language and becomes a creole. After that, the creole would become the people's language. It would take generations before the pidgin would become a creole, though. My biggest source for this was Advanced Language Construction by Mark Rosenfelder. It dives into real-world linguistics and how to create naturalistic languages. (If you're interested, you should probably start with his Language Construction Kit.) [Answer] I think the answer depends on the kind of language and the degree of complexity, and also the difference from the other languages spoken by those who want to learn the language in question. So, for example, if the two languages were like Spanish and Italian, then having one simplify to resemble the other would hardly be necessary. However, if one language was Spanish and the other, say, Cherokee, well, that's a different story. [Answer] Our language gets increasingly complicated because people look for a word that means mostly want another word means but not quite. Or they use new, made up, words or old, redefined, words to distinguish themselves from the people who speak the other way (slang). If slang is used often and long enough, it becomes part of the official language. Gay use to mean happy. We also live in a world of increasing knowledge and complexity. We need new words just to describe new objects, events and ways of thinking (or we could just slap words together like the Germans do). o.m. already referenced 1984. Reducing complexity and restricting the growth of the language will force thought patterns into restricted and controlled processes. So, as much as I think that most slang displays lazy/stupid thinking, I would never consider banning it. Messy language and messy thought processes are likely what helps us be so creative. [Answer] Mostly, no. Under special circumstances, maybe. After all, it's been tried before - well, not simplifying the language, precisely, but people have been trying to control and prescribe language throughout human history. We have documents from ancient Rome where writers complained about young'uns today mangling the language. France has the French Academy which attempts to provide an Official and Authoritative record of the French language, but whose decisions are widely ignored. Centralising language appears to be generally ineffective. When humans need to communicate, they will create language that suits their needs. It happens automatically, whether a central authority wants it to or not. ## So, what are these 'special circumstances'? Basically, humans can't control language. We can use it, but we can't control it. That doesn't mean that something more than human can't do it. In the [Culture](http://tvtropes.org/pmwiki/pmwiki.php/Literature/TheCulture) series by Iain Banks, the Culture mostly speaks a language called [Marain](http://trevor-hopkins.com/banks/a-few-notes-on-marain.html). It was created from scratch by, and this is important, the super-intelligent Minds, AIs, that effectively run and maintain the Culture, and was designed to be "phonetically and philosophically as expressive as the pan-human speech apparatus and the pan-human brain would allow". It may also have been designed specifically to mold the minds of those who spoke it, to help shape the thoughts of those who spoke it, and enable them to fit better into the Culture's peaceful lifestyle. This is what it would take to produce a widely-used artificial language - a way-more-than-human intellect. [Answer] It generally makes sense to simplify the language and some governments have already done so as mentioned in other answers. But let us look at what is really difficult in learning the language and how it applies to English. The number of grammar rules is significantly less than the number of words. People use about 10,000 words in everyday life and the number of words and word phrases in English on dict.cc is more than one million. For many languages learning the words also means learning how to write them. If each time you learn a new word you need to learn how to write it then you need two times more effort to learn this foreign language. All the reforms that I know consist of simplifying the writing system because there you can achieve more in terms of simplification without reducing the expressiveness of the language. Let us look at the English writing system. The writing system is irregular for the first 1000 words, but as you start digging deeper and learn the rarer words you find out that they have very few irregularities in writing and almost all confirm to the writing rules of English (which very few native speakers know). So in terms of writing system English is easy for rare words which need the most time to learn. In terms of grammar English is already simplified by being a mixture of multiple languages in its past. There are no cases and no gender. And it is easier to start speaking English than almost any other language and much easier to speak without errors. Therefore I would say that English as an international language is partially a conscience choice. If there was an easier language in EU to learn than there are chances that another language would have been chosen as a language of communication. The most spoken mother language of EU is German which is by no means considered an easy language to learn. There are still ways to simplify English: 1. writing system corresponding to pronunciation (writing of not that many words is improved in English) 2. eliminating noun and verb endings completely. (e.g. Yesterday I go to school) 3. use constructed forms instead of distinct words (cheap could become im-much-cost (analogous to malmultekosta in Esperanto)) 4. reduce number of words in use 1 can be done without changing the way people speak so it is the easiest. 2 is done by all beginners of English language and is easily understood by native speakers. 3 will significantly change the vocabulary, make the language uglier, but can half the complexity of English. 3 will not change the number of words in use and the expressiveness of the language. 4 will reduce the expressiveness of the language. I would say that it is already partially present in international English. [Answer] The question you need to ask is "why they haven't done that already?" Elephant is one example, why use such long words when we haven't used all the short ones? Why they named it elephant when they could go with "af" Why you say Q when saying Queue? There is also a song called "Gudbuy T'Jane" which you read exactly like "Goodbye to Jane" so why we still use the Goodbye? Which is short from "God be with you". So maybe you can simplify the language but you need to just pinpoint the right moment. Also the whole futuristic movement was trying to simplify the language. [Answer] Yes, one of the government's projects years ago during the Jimmy Carter administration looked into this as I recall, and it was made into this <https://vimeo.com/66638573> during the time of the United States considering a conversion to the Metric System in the 1970s. the letters ABCD would remain the same. The letters E and F would become one letter pronounced "EF". The rest of the letters are modified as shown, hopefully the video shows up, and gives useful information for this subject. [Answer] This happens all the time but as a natural process rather than being planned by some central authority. For example English used to have gendered nouns that disappeared sometime after the Viking invasions. The theory is that Vikings, who were obviously learning English as a second language, never learned to speak it perfectly and their simplified version of it eventually became dominant. Also take a look at pidgin languages: <https://en.wikipedia.org/wiki/Pidgin> When two cultures with different languages have a lot of dealings with each sometimes a new language emerges which is a simplified mix of both. ]
[Question] [ This is something that is starting to bug me, I'm creating a universe in which space travel is cheap and comfortable and space habitats can be built roomy enough that no-one actually needs to live on a planet anymore. If we can live in space, with gravity, open spaces, fresh air, and grow sufficient food off-planet too is there any reason to actually live on the "nasty heavy places" that are planets? Answers should be applicable both for near matches to Earth for habitability and also for worlds that require rather more effort to colonise. Good answers will focus on the relative advantages of planets when compared to smaller but equally comfortable habitats, and bear in mind the effect of gravity wells on relative commercial costs. [Answer] Security I'm surprised nobody else mentioned that already. A space station is an artificial habitat within a hazardous environment. This artificial habitat needs to be maintained and run to avoid a breakdown. A habitable planet is a natural habitable environment which regulates it self. Of course there are natural events like storms and eruptions, but we should know how to deal with them, avoid them. All in all it's probably safe to say that a space station will fail much more easily than a planet. [Answer] If nothing else we would need planets for raw materials and therefore have at the very least mining colonies or penal camps. You can't produce metals, plastics and all the rest from nothing. Also you can't have a closed ecosystem without it eventually deteriorating, there is always a loss however fractional. Evaporation, energy, food and everything else needs input at the bottom, it's not just a matter of recycling. Even with our whole planet we're experiencing scarcity of some resources. [Answer] Because they're beautiful. I don't know what exactly your habitats offer in terms of technology, but nothing short of full VR would convince me personally to live in a space station where nature is confined to parks and you cannot stand on a mountaintop and watch over miles of untouched taiga. This is an important factor for human well-being, don't underestimate what people would pay for it. If the planet is earth-like in the first place, it wouldn't even be expensive to colonize. Land could in fact be extremely cheap: it's not needed for agriculture anymore and all the "urban" people are in space habitats. Of course, nature isn't just for aesthetics alone, it also enables activities like hunting and hiking that just need lots of space and can't really be reproduced properly on a habitat (unless, again, you have VR). [Answer] Yes - It's the Sky. Although space habitats such as O'neil Cylinders can provide you with anything you desire in terms of atmospheric pressure, composition, and density, and also plenty of 'living space', only planets can provide you with an infinite sky. This is your view in a Bernal Sphere: [![enter image description here](https://i.stack.imgur.com/AjFAF.png)](https://i.stack.imgur.com/AjFAF.png) Here is your view in an O'Neil Cylinder: [![enter image description here](https://i.stack.imgur.com/k4ekx.jpg)](https://i.stack.imgur.com/k4ekx.jpg) When you look up, or out, don't tell me you wouldn't surely miss this: [![enter image description here](https://i.stack.imgur.com/lbAo6.jpg)](https://i.stack.imgur.com/lbAo6.jpg) Long story short: people at the moment pay good money to be at an ocean's edge, looking up at the sky or across the ocean. Perhaps it's primal instinct, perhaps it's just because others want the same, but in the end you can't argue the endless sky isn't still desirable. [Answer] Too many people in space. [![hillbilly relaxation ranch](https://i.stack.imgur.com/vHuYT.jpg)](https://i.stack.imgur.com/vHuYT.jpg) <https://www.vrbo.com/874262> Space is very popular. Lots of people live there. The food is great. The schools are great. There are hundreds of interesting experiences all the time. It is like living in the big city: rich, diverse, amazing and stimulating. And it can be too much. Some people get overwhelmed by all of that, and especially the proximity of so many other people. They want to be with one or two other people, and no-one else for miles. You cannot really do that in space with any quality of life. But you can in Missouri. [Answer] Gravity - genuine, spacetime-based gravity. There is one thing that planets have, by their very nature: genuine gravity, created by a massive body warping spacetime. Using known science, we can fake gravity decently enough by spinning our (lower-mass) space habitats, but it's still not quite the real thing. Why would we need curved spacetime, rather than a rotating frame of reference? And why would we value it enough to pay the launch costs associated with a gravity well? That, I'm not sure of. Especially if we can build the habitats wide enough (and spin them slowly enough) that rotation-induced dizziness isn't an issue. But, if you find some reason why genuine gravity is valuable, then this could very well be your answer. [Answer] There isn't much reason, other than tradition and/or novelty. If you can build a planet-sized amount of living area more easily than terraforming a planet, then why bother with the planet? Especially given that on a planet, you'd have to deal with a steep gravity well in order to get back to the rest of human civilization. This isn't to say that zero humans live on planets, of course. The Earth itself is still thoroughly festooned with life, including humans, and will be until the expanding Sun renders it uninhabitable. And occasionally you get a group of colonists who set up shop on a planet just for the fun of it. But most of humanity? They're up in space, where land is cheap and delta-v costs are low. [Answer] Relatively easy creation of livingspace. A spaceship has a lot of requirements to be liveable, like being airtight, not wasting space, requiring energy input to constantly filter the air, specific design for artificial gravity, protection against radiation etc. A planet even one in the process of terraforming, if it can be terraformed at all, would meet those requirements much more easily than a space-ship. Having a livingspace like a house that can be build from brick and mortar rather than airtight structure with radiation-shielding could be very convenient. Planets can also offer stimulation in the views, vegetation, animals and challenges like the weather (if appliceable) that many humans could enjoy. While the creation of space elevators could be relatively costly, the experience, culture and livingstyle could be very welcome. [Answer] Self-sustaining ecosystem and protection from long-range weapons such as particle beams. As others have covered here, a self-sustaining ecosystem in an O'Neill Cylinder is difficult to produce, and requires constant maintenance. It may well be that living on planets is significantly less stressful for occupants, and may be preferred. Another possibility, few really seem to have considered here is the wonderful ability kilometre after kilometre of atmosphere has to defend those living underneath them. It doesn't seem particularly unlikely that in our own future, and in that of a hard (or even firm) sci-fi universe weapons such as railguns and particle beams will be feasible technologies which can cheaply and effectively attack targets from distances measured in millions of kilometres, if not astronomical units. A good example of a cheap, long-range, one-shot killer would be something like a [Casaba Howitzer](http://toughsf.blogspot.com/2016/06/the-nuclear-spear-casaba-howitzer.html) concept, courtesy of Matterbeam. A single nuclear lance is, as that article describes, cheap to manufacture (especially for a spacefaring civilisation), devastatingly effective at long ranges, and unimpeded by even heavy spacecraft armour. Your fancy O'Neill Cylinder ain't looking so attractive a place to live when enemy combatants with cheap, mass-produced single-shot killers can slice it in twain, after all. But, as Matterbeam's blog dictates, the Casaba Howitzer can be stopped - atmospheres are incredibly effective against such weapons. This goes for pretty much any particle beam I can think of (that doesn't run on exotic physics like some kind of q-ball or strange quark gun) as well as any design of railgun that isn't inordinately expensive. The atmosphere simply absorbs all that energy. Going on from this, if a paranoid government is involved, it may be that there's a benefit to keeping subjects confined to a planetary surface which can be covered not only by spy satellites, but also those capable of dropping "Rod From God" weapons from orbit, thus preventing some kind of major-scale uprising. Another another reason might be using the entire planet as a heat sink. Some weapons, defensive or offensive, are simply not feasible to build in space (or sometimes, even on airless moons as there's little atmosphere to convect away heat buildup) but may be better built on planets, say using lakes or oceans to transfer heat away from a vast laser array, perhaps used as a weapon, perhaps used to accelerate lightsail craft to interstellar velocities. Alternatively, maybe vast computing needs also require considerable computational substrate and heat dispersal. Consider that the entire asteroid belt is estimated to be about 3-4% of the moon's mass - not bad, but if you're looking to build a galactic civilisation, maybe it is time to start thinking bigger. A gorgeous planet whose naturalist outer layers hide vast quantities of industry and computing power is certainly an attractive image in my mind, and one I'm currently toying with for a few short stories about future Earth. Another possibility is as a status symbol - perhaps only the top 1% of the top 1% can afford to live on the relatively-rare habitable planets in your universe, being wealthy enough to also afford the cost have transferring themselves and any resources they desire up to or down from orbit. Alternatively, if structures such as Orbital Rings are common, it may be that the upper middle classes of your society live groundside, because they can afford to have goods shipped down to them, or get a flight up to planetary orbit for a line of profession that requires microgravity. Lastly, maybe your setting's constructed physics places some limitation on such things. If FTL travel is restricted by gravity wells, and there's either no other way to interdict FTL objects, or it's terribly expensive, perhaps most non-military, non-corporate cities will use the mass of a planet or moon to protect themselves from vast armadas of DOOOOOOM. Have fun :) NIJNA EDIT: another possibility that occurred to me is that of truly enormous artificial habitats, such as Orbitals from Iain M. Banks' Culture series or a Ringworld from Larry Niven's, err... Ringworld series, might also be an option. Collossal enough that they feel like planets, generating gravity through spin over millions or tens of millions of kilometres, but also a vast testament to the hubris of man's works. Perhaps mixing and matching this with real planets might be an option, who knows? [Answer] I'm going to run, largely, on the basis I established in [this answer about space exploration](https://worldbuilding.stackexchange.com/a/103829/681). # Some would be happy in habitats Many people are happy with life as they are shown it - happy to extend the boundaries of their comfort, happy to concentrate on the details of contentment. Many people would happily live in habitats of one or other kind, enjoying the metropolitan cuisine and easy travel between sites in space, unwilling to descend the gravity well to a planet surface that is difficult and expensive to escape from. # Some would risk it all for planetary life And yet. During the colonisation phase of the Americas, European migrants spent their life savings travelling in order to start a new life, one filled with hope and promise but also risk and hardship. Many did not have the resources to return once they arrived. Why did they go? Some sought freedom from the strictures of their homeland, some sought opportunity to own their own land. These same motivations apply if you live on a habitat; habitats are not easily expanded, and unlikely to have large tracts of freely available space. If you're on a successful habitat, competition for space and resource will be high, and the pull of moving to a planet which has all the freedoms you lack will be irresistible to many. Not the old, for whom the reduced gravity of the habitats made life easier, and who could enjoy zero-g swimming and other pursuits. But for the young, eager to escape the dizzying complexities of hermetic community, the entrenched social hierarchies, the low-risk attitude which permeates every committee decision, it would be a chance to live their own lives. [Answer] Sure you can have "all the comforts" in space, but that stuff is so darn *expensive. Who can afford to pay for that for their whole lives? Planets have free gravity, free atmospheres, and the raw materials you need to build a settlement are already right there. It's certainly possible to live in a space habitat, but living on the surface somewhere is just so much easier and cost-effective. Plus, a planet's surface gives you something to explore. No matter how hard you try, you can't make humans not* explore something. That's the whole reason we got out into space to begin with. A planet's surface is just a giant adventure waiting to happen. Space habitats are predictable, controlled, and boring. Who would be content sitting in orbit, staring at that fun from afar instead of going down and living in the middle of it? [Answer] Space A ship can only sustain so many people. Presumably, people don't want to be subject to extremely stringent rules about procreation. If these people were to never move off the ship, they'd have to be careful not to over-populate, otherwise they might end up in a situation where one life needs to be chosen over another. A planetary habitat is far easier to expand than a space ship, alleviating all these concerns. [Answer] Natural instinct. Space is hostile to human life and even with the best technologies for creature comfort it remains a largely empty, deadly void. Also, even the best space based habitats with plants and animals are still artificial. Planets offer the only original and natural environment. Even though there are conditions threatening life and comfort, depending on the planet there is an abundance of zones most suitable for humans and resembling their origins. Vast areas of nature trump cramped metal corridors and recycled air and water. ... unless your civilization builds planet size ships with their own ecosystem, including atmosphere and sun... [Answer] A good planet gives you a thick atmosphere and lots of stuff to burrow under for protection from the worst solar flares. [solar flare](https://en.wikipedia.org/wiki/Solar_flare#Hazards) A bad planet has its own dangers which make it even less survivable than staying in space. If you have a particularly benign, dependable sun then space habitats might be completely safe. Until some extremely rare event happens that tends to depopulate your many habitats. On the other hand, with sufficient technology and material you might get a space habitat that was shielded well enough. You could collect a whole lot of material to use as shielding, and also create a giant magnetic field to deflect charged particles. [Answer] Why wouldn't you still have planetside colonies? Planets are massive free living spaces covered in abundant resources (in some cases unique resources). For the most part they are self maintaining and even better zero energy (infrastructure wise). One colonized planet can house more humans and industry than millions of space stations. Lots of industry is just easier planetside, especially industry that relies on combustion. Then you have materials that are only found on planets like large crystals, petroleum, or limestone (or a hundred other aqueous forming minerals) . The other thing planets can do is support massive biodiversity, especially of massive living things. We are not going to build colonies with hundreds of cubic miles of artificial ocean to farm 400kg tuna but we might seed a terraformed planet with them. Trees are even less desirable on space stations, they need a lot of space but lumber is super useful. Shellfish, megafauna, trees, tree-fruit, gemstones, marble are all exclusive to planets or so much harder to produce in space that shipping cost is immaterial. If energy is so abundant interstellar travel is commonplace then getting in and out of a gravity well is a triviality. Colonizing a planet is relatively easy compared to building enough space stations to support the same number of people, especially with comparable standards of living. [Answer] ### Earth like planets Planets with a pre-existing earth-compatible biosphere surely would be nice, however they do not exist. The odds that life evolves on another place, in such a fashion that we can breath the air, eat the plant, etc. is small enough to be considered nonexistent. Any pre-existing biosphere would also have a major competitive advantage over earth life, due to already being perfectly adapted to the place, making such planets all but impossible to terraform. ### Terraformable planets To terraform an entire planet, to the degree that you could live there without any technology, is an major undertaking. Once done, it's a nice place to live on, but during the process, you are just as technology-dependent as in a habitat. On top of this, you have all the downsides of a planet (gravity well, weather, nighttime), combined with the downsides of a habitat (technology dependence), for, realistically, centuries. ### Summary We are going to look back at the predictions of terraforming, just as we are looking back of the predictions of flying cars and tube-mail. The planet-fetish that is evident in both sci-fi and even in some futurism, is a passing phase. If humanity sticks to planets, we need the entire galaxy to reach K2. We can do K2 without leaving sol. Planets are building material. [Answer] The resources argument is specious for raw materials: High temp materials -- sand (silicon, oxygen) Aluminum oxide, iron, nickle and heavy metals are present in the asteroids. Comets are a mix of stuff but mostly water and methane and ammonia. Saturn's rings are mostly water ice. Jupiter's upper atmosphere is mostly hydrogen. Energy is very cheap. Blow a bubble of plastic 1 micron thick 1 mile in diameter, plate the inside with a 10 atom thick layer of aluminum, Glue a hoop onto it, and you have two mirrors that put 20 million square feet of sunlight on a 100 foot diameter spot. Melt almost anything. If you have hydrogen fusion, then flitting about the system is easy. Earth to Pluto is 17 days at 1g. The moon is only 3 hours. So we're talking travel times comparable to the age of ocean liners and channel ferries. Shipping goods is really cheap if you aren't in a hurry. Minimum energy transfer orbits from jupiter moons to Mars, say, are a few km/s Do you care that it takes several years? For a tank of liquid hydrogen or methane, probably not. This year's fashion in belly button tee-shirts probably. So, why go to a planet? * If it has an ecosystem, you have a huge selection of botanicals -- stuff premade instead of requiring many manufacturing steps. Not all things can be grown in captivity. * A place to holiday. Consider a future where most people live in space, and holiday on Earth or a terraformed planet. * A place of beauty. * A place of challenge. I have a tough time seeing the equivalent of the America's Cup on a habitat. Mountaineering without a space suit. Shooting rapids in northern Canada. * Gene pool. A place to verify that your genes haven't drifted too much. (See Gordon Dickson's short Call Him Lord) Also a source for things you didn't bring with you the first time. You may actually need a tape worm for something. * Storage. What place better than a planet to store a lot of spare air? [Answer] I can come up with at least three reasons--resource mining (that's a big one), fabrication, and niche entropy. (This is all ignoring just how much work would have to be done to make space that habitable, as it's included in your premise.) I'm going to lump resources and fabrication together here, as I believe resources-alone was covered earlier. The reality is, there are many processes that do not occur outside of microgravity; which is precisely why we do experiments aboard the ISS. The only alternative is in free-fall, which is not economically viable. That said, an equal number of processes won't work in zero-G, inclusive of everything from distillation to [lighting a candle flame](https://science.nasa.gov/science-news/science-at-nasa/2013/18jun_strangeflames). Many materials require gravity as an inherent part of their manufacturing process. Second, I'm pulling the entropy card, but in the context of an environmental niche. It's likely everyone here has heard of the Heat Death theory for the end of the universe; but it happens on smaller scales, too. A life-supporting environment generally has to maintain an extended descent into chemical equilibrium, without actually getting there; if it does, everything goes inert (which, in the context of "people", means dies). As an example, [each individual on the ISS goes through about 20 lbs of oxygen per day](https://www.spaceanswers.com/space-exploration/do-they-make-oxygen-to-breathe-on-the-iss/); generally created through electrolysis of H2O from the solar arrays. You can't recombine that with hydrogen without losing the very point of having the oxygen. These resources have to come from somewhere. For a region the size of a planet, particularly one in a Goldilocks zone, that descent into heat death takes many orders of magnitude longer than it does for a space station. This means that even if living in space is affordable, it will still generally be more expensive than living on the ground. [Answer] Survival There will always be some who take the long-term view, and care that their species or their part thereof has a long-term future. All history suggests that civilisations always fall. The fall of a space-based civilisation in artificial habitats would be fatal. They are nodes in a mutual support network. It's harder to see how the fall of a planetary civilisation could be so fatal (though it's by no means impossible). Usually some survivors on a planet that's habitable, would start to build civilisation from scratch. I won't try to make this case any further. Vernor Vinge makes it absolutely perfectly as Pham Nuwen's back-story in "A Deepness in the Sky", including how an advanced and peaceful civilisation might fall, even absent any malign intent at the start of the fall. Read it, if you haven't already. Also, space Slightly paradoxically, a space habitat will always be crowded. A planetary surface need not be, if the number of people living there is controlled. and sky? We don't yet know if there's an instinctive longing for real sky in human beings. There are some hints that the longing for grass under out feet is more than a cultural artifact, but of course there's no reason one cannot grow lawns in a decent space habitat. A really big one could even fake up the basics, with a blue cylinder / low G engineering section down the centre axis of the cylindrical habitat. You wouldn't see the ground opposite as "sky" or the ground curving up more than 30 degrees or so. [Answer] It's fairly late for me but I will try to write a passable answer and add details tomorrow. # Too hard to sustain A colony entirely in space is hard. You cannot recycle everything. There are things which will be consumed (by humans, machinery, etc.) that cannot be reduced to its base ingredients easily. Even on our Earth, which is a closed system (similar to your spaceship, albeit on a much larger scale) where trees solve our air problems and dozens of other natural processes do much of the regulation for us, we are still experiencing shortages. On a spaceship, where the majority of your energy will likely be going towards maintaining a livable atmosphere, these problems are only exacerbated. On a planet, you can focus on secondary things to survival like building a society, in order to make sure that people don't start murdering other people. On a spaceship, you also have to worry about keeping people alive for longer than an hour. Population The population on the space station will grow unfettered, as there are no natural threats. Assuming the people on your ship are mostly healthy and not in danger (e.g. there are probably few infectious diseases and the crime rate is low), the population will exponentially grow. Even if the birth rate is strictly enforced, this only slows the onset of the problem. Also I just realized the first sentence rhymed One way to counter this might be gladiatorial kill-offs where people are pitted against artificially introduced threats imported from another planet. Survivors can then be recruited for physically intensive labor, and the fights can also serve as entertainment for the desensitized space slave citizen. If you're willing to go full-on dystopian, the corpse can be served as food. # Atmosphere Massive amounts of energy will be needed to keep a breathable atmosphere. Also, if something goes wrong, a lot of people die. You can potentially solve this with a very powerful energy source that will not be exhausted in the forseeable future, e.g. a Dyson sphere, but that brings up other problems. # The view People really like looking at nature, as evidenced by the fact that people go great lengths to essentially look at the terrain. (To be fair, Earth is pretty.) # Why stay in space? The question does not give much details on this, but there is no real reason to stay in space. Planets are there already, and there is no construction necessary. Even if the costs are negligible to build a mega-space station, planets are capable of sustaining much more people than a space station (depending on the size). TL;DR: Space gladiators = dinner for everyone + population control [Answer] Population crisis A space ship can only sustain a very limited population, and a strict population management is needed for survival on the ship. On a planet, there is a lot of space for a growing population (and a lot of stuff to build more generation space ships). I remember reading one science fiction story where the crew of a generation ship is pushed out of its comfort zone by a programmed growth of population to force it to colonise the target planet. ]
[Question] [ In my yet to be named sci-fi universe humanity has begun to expand into space and has established large scale space stations near Earth and on places like Eros and Luna. I wanted the stereotypical "spacer" to have more children than is usual on earth (1 or 2). Are there any logical reasons or advantages for spacers to have multiple children in a space colony? Note: * The Hegemony (global government which controls the majority of humanity) practices birth credits (after a couple's second child they would need to buy permits for any further child) to try and prevent drastic population growth, but in my mind I don't think simply wanting to have more than 3 kids without buying a permit is a good enough reason or motivator to move to space. * Space stations are required to be built with "Maternity Centers" which allow pregnancy, birth, and development to be done in near earth gravity. * Most space colonies are built around mining and/or energy generation, manufacturing, and trade with other colonies (and for certain resources that are worth the cost) and Earth. As well as science experiments and tests on the side [Answer] ## They're called maternity centers for a reason The maternity centers are required because zero-G sex is both confusing and inefficient. Also, fetuses developing in zero-G usually lead to miscarriages or present significant deformities. However, given how these centers are built for the purpose of facilitating pregnancy and childbirth, they make sex far more... efficient than here on Earth. Be it due to the sanitary conditions, the feromones mixed into the air supply, the technology in the post-copulatory pod, or an idiosyncrasy of the gravity-generators, the fact of the matter is that if two fertile individuals have sex in a maternity center, a baby will probably be on the way. Combining this with the fact that spacers are still human, and that [humans ain't nothing but mammals](https://www.youtube.com/watch?v=xat1GVnl8-k) with an innate desire to have sex, you'll therefore have just as many people having sex, but with a greater rate of pregnancies. --- As to why the maternity centers aren't modified to get closer to Earth-like pregnancy rates? One option is that that's not an option: the technology used in the centers is binary. It either works very well, or it doesn't at all. A second option is that fertility rates in space are high because the mortality rates are also very high. No technology can mitigate the fact that space is a far more dangerous environment than future Earth. Be it errant gamma-ray bursts and asteroids or just good ol' cosmic radiation, people die in space. A lot. So if you want your line to continue, you need to make multiple... investments. In case your technology is such that the dangers of space have mostly been mitigated, you can still use this idea: the dangers might've passed, but the spacer culture grew with them and now 3 kids is just... normal. People have 3 kids because they have 3 kids. [Answer] There's not a lot to do in space, so bored people in close quarters resort to what they always do, and have large families as a result. The small families that are the norm in today's developed world are a historical anomaly. In rural China, it was nearly impossible to police a "one child" rule until they became more economically developed, because rural people had nothing to take away. If evicted from one bush, they just sleep under another one. Jail meant more and better food, and better shelter. Your miners are in a similar position, jail time trades hard dangerous work with some liberty for easy living and guaranteed meals and marginally less liberty. With the loss of income, the government takes on responsibility to feed and care for the family. The government can't take anything away without it costing them (the government) more than they gain. [Answer] Attrition Also one of the reasons rural medieval families were usually large ones. Because space stations represent the frontier, the most hazardous jobs and the workforce handling those jobs would be found there. A high attrition rate could come from pioneering exploration into unknown and likely dangerous environments, technology being inadequate to keep the colonists safe, or even a willful disregard for the safety of the colonists from the Hegemony. The Hegemony could be too corrupt to consistently enforce proper quality control and safety standards, or they could simply not care about their lives enough to bother. Throw in the expectation that children would be expected to join the workforce from an early age to round out the explanation. [Answer] Eugenics. Most people are not cut out for long term space life. A lot of people degenerate within a few years in low gravity - malignant osteoporosis, accelerated atherosclerosis and other diseases. After wasting a lot of effort moving people to space only to have them sicken and die, the Hegemony systematically studied the genetic differences between the rare people who can tolerate long term space life and the majority who cannot. People with the optimal genotype for space were really hard to find. They are less than 0.1% of the population, and many were too old or had other issues precluding a move to space. But now that there is a working population of the correct genotype in space, the Hegemony is very interested in breeding more. Space folk with their superior genes are encouraged to have as many space-ready kids as they can. [Answer] Why did people in the past had large number of kids? Simply said: higher infant mortality, so one family needed a lot of born kids to be sure that a few could make it to adult age. I see no reason why space should be different. Whoever has had a baby around can testify how incredibly "dumb" they can be when it comes to dealing with dangers: * sticking a pointy object in an electric plug * swallow a mouthful of acid or bleach * walk over a step just because * pushing a bean up their nostril * etc. The above are things for which any parent on Earth has to be vigilant. Now you are putting those things called kids into a mining environment in space! Space is lethal already for well trained people. The difference between life and death is often the blink of an eye. Mines are lethal too, no need to explain why. To me it simply makes sense that kids in space will have higher mortality just because they are kids. Therefore, instead of devoting additional energies to chase those fluffy fruits of their loins, the Spacers find more effective to put more effort in making more kids. At the end there will be no surplus. Additionally to this, as Joe Bloggs pointed out in comments, simply growing up in microgravity has a whole host of complications. Can you clear mucus from a cold off a child’s lungs if their airways are blocked because their cardiovascular system is designed for constant acceleration, or will it be lethal? [Answer] Going agaisnt the Grain of answers here, but I don't think so. Space is different from living on a planet. You can go a month without food, 2 days without water and probably 5 minutes without air. Resources are limited. You are either relying on the outside world bringing you the resources you want or you need machines to produce and recycle everything. Either way, the amount you can get and store is limited. Having lots of kids means more resources are invested into the Kids and aren't returned back to the colony for a long time. There is the traditional Food, Air and Water you need to keep the extra person alive, but you also need someone to look after the children. Thats someone not working (especially during the first couple of years) on producing the product which keeps the colony viable and afloat. You also need a bunch of extra resources that your working population don't need. Baby Formula, Nappies, baby clothes, cribs, stroller, toys, childrens books. So children act as a giant resource sink for a colony which more often than not, needed to produce goods to keep receiving essential supplies and stay alive. You will also eventually run into a resource wall. When your 3 kids each have 3 kids of their own, and these 3 kids have 3 more. Every generation your population increases by 50%. Thats 50% more resources consumed (probably more if you factor in construction to make space of the extra people). Eventually your population (without proper control) is going to outgrow what you can produce and start to cost you money to keep alive. So letting people have many (3+) kids isn't a good idea. Its a resource sink which you will likely see no or little benefit to and it costs you a ton of resources and ties up part of your potential workforce in daycare. It would be better for that to occur on a planet where you don't need to worry about running out of Oxygen, Water, Food or Space and then shipping proper working adults into the actual colonies to do proper work. [Answer] ## Organs Medicine has advanced to such a degree that most people can live for many, many years. But their internal organs keep failing and need to be replaced from time to time. Not a problem on Earth, where there are clonal factories, but these factories are too difficult to set up in space (and there are crippling licensing fees as well). So, you harvest organs from your children. Initially, there were competition rites during coming of age, but people soon realized that physical competition is counterproductive - the healthiest, fittest survive, and you get the organs of the weak ones. So by now, the competition is purely mental, the children know it's either them or their siblings, and the most intelligent wins. After generations, natural evolution starts to assert itself - most of the miners are weak, with failing health (requiring constant supply of new organs), highly intelligent and completely sociopathic. And, since you never know when you need a replacement, people always live in fear that their parents might "harvest" them, even in their adulthood. So they prefer to sire children as soon as possible, to offer grandsons instead, in time of need (genetically, they are a bit less desirable, but still - and they do not fight back). [Answer] My father comes from a family of 12. His parents were farmers high in the mountains of Puerto Rico. The reason why would appear fairly simple to begin with. The need for laborers in a large coffee farm was great. But the more I think about it the more I suspect there were other reasons. Initially each additional child would add a sizable drain on resources without contributing anything to the economy of the farmstead. Farmers are used to waiting for results but still... Isolation contributed to the situation. Most children where born at home since a hospital would have been a whole day's drive at the time. This would have meant little to no access to contraceptives. The lack of other entertainments may have also been a factor, but as someone who has father two children I know how difficult it is to find the time or energy to create the second one. Isolation would have also provided plenty of space to spread. In my opinion there is only one real reason why a space society would disregard limited resources and have oodles of children in spite of the risks. Religion. In New Zealand, where I now live, there is a large community that call themself "Gloriavale Christian Community." This 500 member Christian cult consist of 55 families with about 8 children each. Nothing in human history has led more people to make decisions contrary to their best interest as a strong religious belief. So to review: labor, isolation, and/or religious belief. [Answer] Space has less distractions. No internet and no shopping means we go back to a primitive lifestyle. ![SMBC](https://i.stack.imgur.com/ZOUjY.jpg) Source: <https://www.smbc-comics.com/comic/cattle> [Answer] While I doubt the following is true, it could be a logical reason in your universe. Zero-G conception causes much higher occurrences of twins, triplets, etc. in humans. [Answer] ## They produce too much food. Maybe your colonies, for having planned too much greenhouses in their prime design (or after mining an edible asteroid, whatever fits your world) grew an excedent of perishable commodities with no way to preserve it appropriately ([some food do spoil in a freezer](https://cooking.stackexchange.com/questions/68678/why-does-food-spoil-in-the-freezer)). So instead of throwing it in space, your settlers eat it as it comes, and the overall abundance ended in more children than previously planned. Which in turn, produced more people working in your "space farms" and results as an increase of perishable food, and so on... Note that having "too much of something somewhere" would also explain the trading exchanges with the others colonies that lacks this "something". [Answer] ## They need the work force Perhaps your miners are very tribal in nature. The colony is very territorial. You and your tribe own a claim. You and your tribe work the claim. Need more workers? There's only one way to make that happen. Why does the colony support this? Because they draft some of the children into military service. So they need the work force too. [Answer] There are a few aspects to consider, the short version being: the purely utilitarian "more babies mean more survive", the moral aspect of "who appointed you to decide how many babies I can make", and the simple fact you need a roughly equal amount of men and women to make the equation $man+woman=baby$ work. Would you like to know more? --- One child policies have problems, and the most obvious one is demography in the form of sex ratio imbalance. Historically, working the farm is a boy thing. The generally patriarchal society might also make it more desirable to have a son, who will lead the next generation of the family, rather than a daughter whose role is to make babies and little else. While a more modern society might not have these considerations immediately in mind, traditions and prejudices die hard. China, which recently abandoned its one-child policy, had a ratio of up to 117 males for 100 females (thanks Wikipedia). The consequences down the line are potentially dozens of millions of males unable to find a mate, unless they go find one abroad (which means living the country which isn't necessarily good for the economy, or importing one with all the human traficking problems it might imply), or unless the family changes towards a more polyandric model which then brings us back to traditions and prejudices that could make such a society unthinkable. This might be workable for large population like China's, or Earth's. For small populations however, if everybody makes two sons that'll work the space mines to bring in all the bucks, you'll soon run out of babies to sustain the population, and that is a real problem. --- Another problem is ethics, namely what gives you the right. The one-child policy infringes on one's freedom to have a family of the shape and size they want. More than that, with the considerations of the previous point, it poses the question of the value of the life of a baby boy vs that of a baby girl. Any advanced society should be wary of that problem, not to mention that one of the main point of settling the frontier might be the freedom it procures, away from the all-powerful government. What gives you the right indeed, cue dumping spacetea into spaceharbours. --- Finally, the frontier is a harsh mistress. Space hates your gut, every new planet is just a collection of unknown dangers ready to kill you. Having spare babies just in case might be useful. That one really doesn't warrant much explaining. [Answer] Manifest Destiny As a result of most jobs being automated almost all people have been living on Universal Basic Income for generations. As a result of this they have forgotten how to work towards hard goals like "building a family" or "having a career" instead choosing to spend their lives behind their smartphone screens. Only a small subset of humanity still choose to work one of the few remaining jobs on earth or move to space. The people who move to space have a strong believe that it is humanity's destiny to colonize the universe. An important part of this is to raise a next generation that can continue this quest. [Answer] Filling in a niche here: ## Demographics The people going to space are primarily young people looking for a better life, with a minority of older (middle aged people). The people staying behind are primarily older people, who have settled down for good, with a minority of younger people. So, which group is likelier to: a) have more sex; b) actually try for children; c) successfully carry to term? [Answer] # Launch Costs Putting mass in orbit is expensive; currently, about \$2k/lb (post-SpaceX.) If there aren't drastic improvements in booster efficiency, that means something along the lines of \$200k per grunt added your spacer workforce. That's a pretty heavy hiring fee. But... with some frugality, a kid can be raised to work-ready age for less than \$200k. Not to mention, the Evil Space Corporations get the opportunity to indoctrinate- ahem, train them all in company schools. It's simple economic efficiency! [Answer] On Earth it is limited by the government policy to mitigate overpopulation. Housing tech There is just not enough space on the planet with the available housing technology. Could be that they are starting to build arcologies to solve it without the limitation. This project is co-financed by the child-credits sold. This is not a problem in space since there is a lot of ... ehm ... space ... and materials to construct artificial habitats and stations. On the other hand, there could (and probably would) be problems with food, water, and air. However, many of the asteroids are made of ice, that could be used to get water and oxygen. Food There is not enough fertile land on Earth to support the population growth. Food has to be imported from space which would make the spacers basically farmers who could profit from the larger workforce. The possibility of this depends on the way you solve the energy needs of your civilization. Hope this makes enough sense and helps :) [Answer] 1) The largest families in my home town were all Catholic. Thus, you might employ religion as a reason for more kids. 2) Also, the larger families tended to be farm families with more kids to help out on the farm. If you can find an economic benefit from putting little hands to work helping the family, and make this economic benefit exceed costs of raising the kiddos then the hidden hand of the market place will favor larger families. I suggest you combine the two notions when designing your extra-terrestrial culture. [Answer] It could be a psychological design to guarantee large populations of young miners in exchange for yet another psychological mining related benefit - Suppose there's an incentive program, not unlike a 401k. With every hour of service in the resource pool, you gain credits toward your ascension from the common worker ranks. By the age of 45 you can take a payout of a position on a small freighter you then own and operate, which is just a disguise to keep them in the mining industry, just no longer in the physical labor sector. You can crew your ship with qualified members, but immediate family members are automatically granted a position on your family vessel if they choose to go with you or are too young to be left alone. The vessels require a minimum of 4 person crew over the age or qualification level of X, which is whatever you want it to be as the writer. Think like lost in space where the whole family works on the ship. Basic level vessels have a capacity for up to 10, so whole families can effectively retire from the labor sector. Ships wouldn't be the only cash out too. You can have plantations managed in the same fashion where you cash out into a head position overseeing the laborers in another mining facility. For each level of incentives, the population requirements decrease to both make it seem possible to get there without having a huge family, but having a huge family is the easiest way to no longer have to drill resources out of the ground. At working age you will have to justify your living requirements, and the easiest way to do so is with credited time on a family vessel, or leaving the vessel and joining a mining crew to begin your own family, as would almost positively happen with generations. And as such, the cycle continues because everyone has to do their time. So in short, having a large family will get you out of hard labor faster, thanks to the unified space ascension act of 2245. [Answer] I will put the other way round and present some reasons why Earth based families have fewer children than space based ones: * Due to overpopulation on Earth there is an effective birth control policy (similar to China's famous one-child policy) in action * Some environmental factors (like chemical polution) have seriously decreased fertility on Earth * A celibatarian cult has managed to get lots of followers on Earth [Answer] # Connect the reason for many children to the theme of your space world. For example, Krypton was destroyed because of irresponsible mismanagement, put hyper briefly. Cal El was born for desire to progress, expand, and survive. Krypton's destruction serves as a monument and warning to not destroy ourselves and Cal El is that message in a bottle delivered to us. What is your world's message in the bottle? What mission, "moral of the story", purpose, virtue did/does this space presence come from and serve? *That* is your main *motive* for having all these children. With that in place, the science can follow it more easily. ...Less distracting entertainment, fewer viruses, better resources, need for company and help on the approaching colony... perhaps a less-charged, less polarized social-political atmosphere where people are more pragmatic. But, all that sprouts from the initial thematic mission for this space travel. [Answer] # Because They Can Humans are biologically hardwired to want children. Having and raising them is satisfying to most individuals. Earth is at or past the sustainable carrying capacity. An educated population understands that and looks for a relatively painless way to get the population down on the long term is to breed below the sustainment level. If the spacers can build stations out of one asteroid, they can build stations out of many asteroids. The expansion is limited by the stationbuilding capacity. The limiting factor on that? Workers. That will work until they run out of suitable asteroids, which is a long way off. [Answer] It seems to me to make a good background point you need a reason for the government of the colony to incentivise large families rather than just a reason for their being large families. To do I suggest set up your space colonies as follows. * Each one is attached to a large pool of raw resouces. Ethier an asteroid, inhospitable moon, giant space fungus etc. * They have free energy. Either cold fusion or room too make as many solar panels as required * They have free food. Yeast farms or whatever, fed by the endless supply of sunlight and CO2 from crushed rocks. * Space travel is expensive. Shipping in machine tools and replacement parts isnt economical. * The initial setup is expensive. Every colony has a large debt to pay back. * Automated factories and the like initially used to produce the exports of the colony tends to break down. Now you have a senario where unless the colony starts to produce its own replacement parts and other day to day resources it will go bankrupt. Given even a simple pencil takes millions of people from all over the world to produce, each colony is in desperate need of crafts people to manually fabricate a million and one things. Only colonies that become self sufficient before the initial equipment fails break even and make a profit. So you ship with as many people as possible and encourage them to breed as fast as possible. Building shelter and feeding them all isnt a problem as long as they all learn to smelt ore, smelt steel, machine screws, weave glass fiber and generally fill in for mass production. A side benefit of this is all your colonists are tough jack of all trade macgyvers living on the ragged edge of society [Answer] Transport Costs and timeframe Depending on the tech you use for moving from one place to another it is very costly to transport living beings. If using current tech they are required to be fed and watered, given clean air to breath and require exercise and entertainment if they are to get to their destination in good shape. Transporting breeding stock is a lot simpler task than transporting the whole herd... Enviromental Factors Maybe the local environment affects the development of the unborn child. Think of local microbes entering the body of the mother passing to the foetus, changing the immune system etc that allows the child to be adapted to the local conditions from birth. As an alternative maybe some other enhancement, ie greater strength or endurance for the mining operation, arises from development and growth on the new planet. [Answer] Related to this, is that space is full of... space. If earth is over populated to the point where I am so close to my neighbor, that I can ask to borrow a cup of sugar through our paper thin walls, in space, the same task may involve four hour walk to your nearest neighbor... and then you need to go back home. I have lived on the East Coast of the U.S. my entire life and for the majority of that time, I have been in one of the denser parts of this area (near D.C. and Baltimore specifically). In my childhood, I lived in a house where the neighbors were "a corn field" and "a Cow pasture"... and then I moved to a more suburban neighborhood that was still so rural that the nearest "Convenient" Store was 10 minutes from my house. By car. Coupled with the many answers that to a rural colonist of another planet, sex is one of the few available past times, kids can be farm hands and the more you have, the more workers you don't have to pay (U.S. Labor laws still do give deference to children below working age doing work in the family business) and religious reasons, it could be that your "family planning services" are to far away to justify having safe sex in the heat of the moment. [Answer] Earthlings Are Heavy Space-based technology has just become successful at autonomous ships and mining equipment. This was based on prior efforts to automate all manufacturing capabilities. Building satellite or ground-based habitats is becoming increasingly cheap. The government decides it's time to start populating other solar systems. Lifting mass into orbit is expensive in terms of environmental damage. That is true for people as well as ships. It just makes sense to work with mass already outside Earth's gravity well. So, the extra population needed is bred off-Earth and sent out in ships built in space. [Answer] The actual science based trend is that spacers would have less children. As people become more technologically advanced they tend to have less children, and this is becoming increasingly exacerbated with more technology. The only plausible solution to this problem is that space fairing people are immortal, and they have lots of children by virtue of just living so long. However their children will still all be adults. Here is some light reading: [Mental perspective](https://www.psychologytoday.com/us/blog/the-narcissus-in-all-us/200903/history-s-mysteries-why-do-birth-rates-decrease-when-societies) [Declining world populations](https://slate.com/technology/2013/01/world-population-may-actually-start-declining-not-exploding.html) In fact one of the theories in the [Fermi Paradox](https://en.wikipedia.org/wiki/Fermi_paradox) is that as intelligent species become more intelligent, their birthrates decline to the point of extinction. So it is not likely that a space faring human civilization would lead to many children. [Answer] In space, no-one can hear you breed While in space, you live where you work. The spaceship / space station is also the family home. The crew are usually members of an extended family. There is plenty of room and the hydroponic system supplies more than enough food for everyone. Finally there is a lot of spare time. It's limitations that reduce the size of a family. Limits on time, limits on space, limits on food, limits on money. In a self contained, self sustaining ship, you have no real limits. [Answer] If the space jobs were higher paying then the ones on earth, space people could be higher earning and more prosperous thus could afford a big family. If there is birthing restrictions in place on earth, it could be good for social status to have more kids. It could be part of the culture of space people to want to increase space population. It could be part of the culture of space people for genetic-diversity (swapping with more partners). There could be some space foster center that removes the responsibilities of parenthood. There could be some positive adaptation to being born in space in which space children are highly desirable. If there were higher demand for jobs than the population. Some combination of the above suggestions. [Answer] This is just a hypothesis, but giving birth is probably a lot easier in low or no gravity, for reasons similar to water birth, but with more convenience. An easier and less painful birth experience is going to make repeating the process less unattractive, resulting in more children. ]
[Question] [ Built within an asteroid belt (near convenient resources) is a densely populated human settlement. While not a "planned city", the settlement has expanded in a organised, grid like fashion in all 6 cartesian directions. Up, Down, North, South, East, and West. Allocations of space within the city are basically rectangular prisms. Tech is quite high - artificial gravity allows each dwelling owner to orient their space how they choose and the gravity field is confined to their dwelling. However not high tech enough that they can put their feet up. Most adults are employed, and most of them need to commute for work. People need to commute for supplies, or education, or social reasons, etc. Just like a modern city, except in 3D. Public transport is non existent. Everyone is using their own "flying car" - a personal transport rocket about 2-3m in size that is basically a car but in 3D. Can get up to 200kmhr on a straight and can do a 3G turn comfortably. The city is overpopulated, very space constrained and densely packed. It can't afford the space to build a 6-way cloverleaf intersection every time 3 main "roads" (voids between allocated property in 3D) intersect. A 6 way stop sign definitely couldn't cope with the traffic, and waiting for 2 crossing traffics straights and 6 sets of turning groups would be a test on everyone's patience, especially if your commute requires crossing dozens of these intersections. The largest "road" is 6 lanes high by 6 lanes wide, split in 2 directions like this diagram: [![enter image description here](https://i.stack.imgur.com/7IBIy.png)](https://i.stack.imgur.com/7IBIy.png) How do 3 roads like this intersect most efficiently? [![enter image description here](https://i.stack.imgur.com/8rNqr.png)](https://i.stack.imgur.com/8rNqr.png) What goes under the blue question mark to allow these 108 lanes to intersect as efficiently as possible? --- Scaling up 2D intersection designs to 3D just don't seem to be an optimal solution, do we prioritise X, Y, and Z seperately using traffic lights? There are 18 turns which don't require crossing incomming traffic, 12 of those are going to have to wait at any one time even though their destination is "just there" - that's going to be very frustrating. A 3-way roundabout (3 circles in X, Y and Z, or a sphere) could just fit if they go really slow, but I'm unable to work out the rules and it doesn't seem very space efficient when the traffic gets beyond a few dozen cars per minute, and I'm hoping to get something like 4000 cars per minute through this intersection. [Answer] ### Adjust each cars approach speed such that you always get a clear path. You know those action movie cliche where a car runs a red light and, despite crossing traffic, the timing is so precise that the car gets through without hitting anything? You can use a central server to allocate slots in space and time for each car. The cars are high tech - so some autopilot system can request a clearence slot a few seconds in advance, and adjust the cars approach speed so that it gets through with an acceptable safety margin. You have a natural 6 x 6 x 6 division of space, each about 3m x 3m x 3m or whatever your lane size is, 216 cubes in total. For a 200kmhr travel speed a straight travelling car with a 3m car length cars will cross through a cube within 50ms. With a safety margin of one car length each car would need to secure an allocation of a cube for about 150ms, and have 3 locked at any one instant. Turning needs different allocations in time and space - many curves are possible, and it could depend on what lane the car enters in. By requesting multiple allocation sets in a priority order the car could do a fast wide 3-g turn that goes through lots of the lanes when traffic is low, but do a tight slow speed corner when traffic is busy by sticking to the edges. By extending this to the entire city you don't need to allocate 18 lanes for each direction - you can flex it based on commute flows. To explain flow here I'm going to introduce a unit called the "cubesecond", locking one cube for exclusive use for 1 second is 1 cubesecond. The intersection is fully swamped when all 216 cubes are locked, so you have 216 cubeseconds per second in budget. Anyways this intersection design should allow a lot of traffic from our 216 cubesecond budget: * With 2-car-length safety margin (occupy a cube, reserve the one in front and behind you), each straight-through at 200km/hr locks 6 cubes for 150ms each - 0.9 cubeseconds per straight transit. This has an upper bound of 240 cars passing through the intersection per second. That's 15,000 cars per minute. + Lower the safety margin and you can get this higher. This is probably nail-biting enough already. * An "Up", "Down" or "not crossing the oncoming lane" turn1 occupies as little as 1 block for about 4 seconds each (tight, slow turn, but with time ), each of these uses 4 cubeseconds. * A "crossing the oncoming lane" turn needs to occupy as little as 4 blocks for about 3 seconds each (tight, slow turn). Each of these uses 12 cubeseconds. * A wide, fast, but greedy turn would occupy about 20 blocks for about 1 seconds each. This is 20 cubeseconds. You could theoretically do 10 concurrent wide greedy high speed turns. * You can mix and match these + If one person does a wide high speed turn in any right angle then ~195 cars could go through straight in any direction per second at 200km/hr. + If two people do wide high speed right angle turns then ~175 cars could go through straight. + 3 wide high speed turns then only 155 cars going straight per second. + 7 cars turning, and ~70 cars going straight, could get 420 high speed turns per minute and 4200 straights per minute. That should match your ~ 4000 cars per minute lower bound. Footnote 1: Sorry, I'm Australian; I drive on the Left, Left turns are easy for me. I can't think in left and right here especially as your system seems to imply keep-right. --- On further thoughts: No public transport kinda implies minimal or ineffective government, this may mean you can't run a central server. In this case - the cars can communicate among themselves on approach to each intersection. You'd basically use a networking protocol (eg blockchain) to build mutual consensus among a network of cars on which car has access to which cube of space at any one time. [Answer] No intersections. [![no intersections](https://i.stack.imgur.com/ghaWz.png)](https://i.stack.imgur.com/ghaWz.png) You want your paths to be like interstate highway lanes. No direction changing or maneuvering - passing slow traffic at most. If you want to change direction you need to get off the interstate and change course out of the flow of traffic. When rocket paths going different directions get close to each other, you want everyone to stay in their lanes and predictable. In 3d they do not need to cross. When the paths are close that is not where you want people maneuvering around to change directions. Each of these various paths will have long on ramps and off ramps set well away from other paths. It will give the rockets time to maneuver, change course, decelerate and accelerate well away from traffic. [Answer] ## Use a roundabout Whilst Ash's answer is excellent when some form of automation is involved (as our current tech is leading towards already), I feel the question implies a lack of such technology. Instead I will suggest something that every British driver is intimately familiar with, the roundabout. In this case, all vehicles will drive in a circle until they reach their exit, at which time they leave. If you drive on the left, you go clockwise, on the right goes anti-clockwise. "But wait," you say, "circles are 2D, what about the other two directions?" I'm glad you asked. The straight-on direction for the other two (say up and down) is straight through the middle of the roundabout. If they want to join one of the other four directions (or someone from there wnats to join the Up/Down) they take a dedicated lane that splits off and puts them on it, much like those used in interstates/motorways. If your city administration is on the ball, they probably know which direction pair is the "primary", and that one can be designated as the straight through route. Even if the primary route is Left/Up you can put a roundabout around the bend. Unless you have a city of competent drivers, I suggest investing in space-buoys to mark lanes. [Answer] Do what city traffic engineers do today to solve super massive congestion problems. ## One way streets You solve half your problem by reducing the intersection to just three directions of traffic and using several other nearby intersections (between one and nine) for the complementary directions. The use of one-way streets means traffic control (or, in your case, traffic scheduling) is substantially simplified — and that's really your goal. Also, a quick frame-challenge alternative You explain that your space is highly constricted and therefore huge cloverleafs can't exist. I'd like to challenge that. You have cloverleafs anyway. From any one direction there are only two of the five other directions that a traveling vehicle can turn into — and even then, at 200kph you can't simply turn on a dime. You need sizeable sweeping curves to get you into those new directions. And even larger sweeping curves to get you into the other three directions (including a U-turn). Cities today inevitably refer to this messy situation as a "mix master" or "spaghetti bowl." Since you have that problem anyway (it really can't be avoided), you might find you actually save some space by off-setting the three paths at the intersection so that they don't directly intersect at all. You're invading the space you need anyway just to transition cars into the other directions. Granted, it will use more space than the mix-master itself would require, but in for a penny, in for a pound when it comes to safety. Right? [Answer] If you want the highest possible flow, you need to split lanes and merge them together afterwards. You have 18 lanes. Split them in 5 possible directions thats 3,6 lanes per direction. Prioritizing the straight, thats 6 lanes straight and 3 lanes in every other direction. That could be splitted like so: [![enter image description here](https://i.stack.imgur.com/1jJ4X.png)](https://i.stack.imgur.com/1jJ4X.png) As for the interchange design, there are a lot of examples for a 6-way-interchange, designed in the game "Cities Skylines". [![enter image description here](https://i.stack.imgur.com/fZW5Y.jpg)](https://i.stack.imgur.com/fZW5Y.jpg) [From Reddit](https://www.reddit.com/r/CitiesSkylines/comments/9puc3w/6_way_interchange/) All you have to do really, is change the directions of 2 ways and you are in the 3rd dimension. You can alter and control the flow and prioritize connections if you alter the amount of lanes per direction. Although this is the best solution for optimized traffic flow, it requires a lot of space. [Answer] ## Side Streets It is a technique I see a lot in Texas, but rarely on the United States east coast. Put a low speed side streets next to the main thoroughfares, and do a classic intersection between them. This means that people who are turning must slow down, but people going straight just keep going. ## 3D roads You've fallen for a classic trap. Your 6 lanes laid out side by side are a 2D design. For a 3D design, at the very least, stack them. What might be better is for each direction to have a two by two grid of lanes, for 8 total. This design also helps reduce the number of lane changes needed. ## Rails You might also consider a rail system. Like our railroads, it would be about keeping vehicles on the thoroughfare. Unlike our railroads, it would be more about guidance than support. It can make self-driving cars and computer management a much simpler proposition. If I were designing this, it would be a central hub that 3 to 6 streams of cars cluster around, using an extended rod to keep in contact with the hub. Supports for the hub would occur between lane changing zones. Local roads might just have one rail, one lane in each direction, and a stopping lane. [Answer] > > Allocations of space within the city are basically rectangular prisms > > > ... > > > (voids between allocated property in 3D) > > > ... > > > The largest "road" is 6 lanes high by 6 lanes wide > > > Would not result in 6 way supercollider intersection with "tunnels" leading to them. You would get gigantic (city wide) planes with 4-way (2D) intersection every block and much rarer 6 way intersections. The largest roads would be 6 lanes wide and city size deep. So You would have much more room and much less traffic density than anticipated. I would suggest that You use 4-car deep inner space for "express lanes" routed through the city, and reserve the outer-most (adjacent to structures) space for local traffic and the "cars" switching "express lanes". For the express lanes You would have only option to flow the lane at high speed or switch to deceleration lane to join local traffic. For local traffic you would have low speed limit and more freedom to go where one please. ]
[Question] [ Inspired by [this question](https://worldbuilding.stackexchange.com/q/113270). I was thinking about the constructed language I'm building and a group of countries in the history of my world, and ended up wanting to ask this question. *Please do take the time to read all of the information under the main headers of "Info" and "A Little History Lesson" and think for a minute on the information contained in the subheaders. It will be important for answering the question and understanding the setting.* # Info ### Setting I have a small little country, about the size of modern day Portugual, called Teyarzhaodaqua (From Teya-Řãonance-de-Aqua, lit, "The sun's domain of water") bordering (the longest border exactly parallel to) a country the size of modern-day China, called Aeðsta. Teyarzhaodaqua is not technologically or magically advanced, has very little education or status, and has few resources and weapons. Aeðsta is highly technologically advanced and has plentiful weapons and resources, lots of education, fine arts, sciences, and many people there are wealthy, as well as powerful mages. Now, I have a scenario in which the language of Teyarzhaodaqua (From now on referred to as LC) becomes the official language (the only language spoken, surpassing the original language) of Aeðsta (from now on referred to as BC). That is to say, the language of LC completely replaces the native (and sole) language of BC (English). ### Background on languages The language of LC is hard to learn (at least for speakers of English, like BC), with an alphabet containing more than 75 characters (26 base letters plus 50 diacritics), difficult pronunciation, and confusing temporal reference system due to verb conjugations among ten sets of pronouns, and occasionally additional meaning is added to the written form by switching the color of the ink, which makes it a pain to write as well. It's not magical and doesn't have any kind of power/religious significance (as a matter of fact, it is occasionally viewed with scorn, since it has no religious significance), takes much more time and effort to learn, is a pain to work with, and isn't really connected to, say, important documents, scholarly findings, ancient works of literature, valuable information, etc. It's not economically important (not learned for trade) and not important for peace talks between the nations (LC'ers learned BC's language quickly, enabling communication.) So it's not important for diplomacy/money. It is a beautiful, melodic language at times, but the pronunciation of some words is alien, and occasionally harsh. ### Important people, and all that stuff The government of BC is a representative republic with three different law systems, each with an elected council: Law makers, law passers, and enforcers. There was no language barrier between the upper and lower classes of BC. LC is an oligarchy ruled by a group of spiritual leaders who make pass all laws within a small council. # A little history lesson ### Isolation The countries of LC and BC are nearly completely isolated from other civilizations due to being a landmass out in the middle of an ocean. LC was the original country that did not cover the entire landmass, but when BC came it conquered LC and all unused/unexplored land. BC was essentially one tribe that came over with one language. What makes this scenario interesting is that LC is literally cut off from time. All of the important technological developments of the rest of the world--from the invention of the wheel to the invention of gunpowder--took much longer to develop. LC's tech level is similar to that of Medieval Europe. BC, on the other hand, has 19th/20th century tech. ### Barrier of Nature Geographically, the little continent where BC and LC are is isolated by a formidable wall of defenses, namely a ring of jagged rocks made of graphite that has been compressed under heat, pressure, and time to create diamond "teeth" that form a vast barrier around the continent. Strong currents mean ships are pulled against the rocks with enough force to smash through wood. Past the diamonds, on seemingly dry land, there's a high wall of rock followed by a sudden depression. When tides are at their highest, the water on the other side of this wall surge over into the depressed ring--a death trap for survivors who paused to catch a breath. And if you make it past that? Say hello to [poison elephants](https://worldbuilding.stackexchange.com/questions/117425/designing-venom-glands-for-an-elephant-misting), trees that [stab you](https://worldbuilding.stackexchange.com/questions/120791/porcupine-tree-needle-firing-system), and [carnivorous silkworms](https://worldbuilding.stackexchange.com/questions/114147/best-material-for-windsilk), as well as snakes whose venom turns flesh to stone and vampiric flowers. ### Last bit of background The local inhabitants, LC, having migrated from another plane of existence (the Light Plane, specifically a planet with 27 suns) have been eking out a living. And now, a couple thousand miles away, a fleet from BC approaches the continent . . . and survives. The two communities are separated by a large mountain range that severs the land into a large chunk and a tiny chunk (that will later mark the boundaries between the countries.) BC is already at the medieval level, but LC is primitive. The two countries develop, isolated from each other and the rest of the world, until they reach the level discussed earlier and BC looks up from all the stuff it's doing and wonders, hey, what is on the other side of those giant, treacherous mountains? And so we come to our scenario, where peace has been (grudgingly) made between the countries, (though conquest may still come) and they are exposed to each other's culture and language for the first time. The paths between the mountains are opened and . . . suddenly they are minutes away due to BC's communication technology. ### Relationship Between BC and LC BC's opinions of LC: "LC is inferior. It has less advanced technology, a weak government, a blasphemous sun-worshiping religion (can you believe they don't worship stone!?), a difficult language, strange customs, and to top it all off they're using up valuable resources and living on our land. But on the other hand, their language is connected to the language of the Light Plane, which is a potentially valuable resource, considering it might be useful for reading the magical tomes in our possession. Perhaps a temporary alliance would be useful. Our religion demands tolerance of other's beliefs, even if they are \sniff\ blasphemous." LC's views on BC: "BC is obviously inferior. They worship stone instead of the sun — how can that be forgiven? They speak a harsh, hard, primitive language while trying to make up for it with their "technology." Well, we'll show them how quickly we can adapt! And they can try all they want to take our land from us and change our religion — they'll regret it. But we need to try to be peaceful for now, since their technology and sciences might be useful to us." # Question (Hey, congrats on making it this far!) *What sociological event or trend (that have happened in our (real world's) history in similar situations) could have made BC make LC's language the lingua franca?* It must adopt both the complex written form and the spoken form. It must become both the official language (what's taught) and the only spoken language (what's actually spoken in the street.) A number of "uneducated souls", like street urchins/criminals/poor people, won't speak much of it, but they have to know enough to get by. This doesn't have to happen immediately, but it has to happen over a period of about 50 years without any major upheavals in religion, government, etc. --- [Answer] When the Roman conquered Greece, they were so fascinated from their civilization that they put a straw in that land and started avidly sucking their culture. It was common practice for students to go to Greece for studying in Greece. This didn't reach that far to replace Latin with Greek, but it gives you an hint of what could be a solution to your problem: not physical grandeur, but cultural. Let the small country have such a strong cultural influence that the elites would find only natural to embrace its language and culture to legitimate themselves. [Answer] Dilution. Summary: LC are the primitives, the conquered; their language is complex but it becomes the language used. BC are the advanced, the conquerors, but their language is lost and LC becomes the language used. There are many, many more of the LC people. The conquering BC people are from a geographically constrained accidental colony. They have advanced tech thanks to their provenance but only a few original colonists arrived and their numbers are few. Additionally they have trouble with inbreeding. The LC people sprawl over an enormous area and number in the hundreds of millions. Resources and inbreeding are no problem. The conquering BC people arrive and are lost in this sea of LC. It is no problem for a BC male to set himself up as a plantation owner, leveraging his tech to make a prosperous farm. This BC aristocrat can have multiple LC concubines who (as opposed to his main wife who is actually his first cousin) bear him many healthy children. In the first generation, his children grow up mostly speaking LC as they learn from their mothers. BC langauge is for speaking to their elders. In the second generation the BC-descended aristocrats are genetically majority LC. They speak LC to each other and BC only at weddings and funerals. Made wealthy by their time in LC country, these descendants also take charge in their ancestral BC homeland and bring the LC language back with them. By the third generation LC is the main language in the developed areas of the BC homeland. People who speak BC as their first language are only found in communities left behind in the outlying BC countryside - isolated inbred rural people. These too are a dying breed as economically they cannot compete with plantations in the LC, and so come to the cities in BC and LC out of necessity and are assimilated. [Answer] It's a trend that goes viral: Initially LC is adopted by only a few of the most highly educated BC elite. It is chosen for this purpose precisely because of its difficulty and obscurity. Only the idle rich have the resources to learn it, and so it becomes the private language spoken by the most envied and admired people, who judge each other viciously on mastery of every nuance and grammatical idiosyncrasy. Overnight it becomes a viral trend among social climbers who aspire to be like the wealthy. However, it retains its cachet among the rich because of its difficulty. Only the truly wealthy can afford to study it with native speakers, and there's always another nuance to master. Over the course of a couple of generations, LC filters down to all levels of society. The function it plays in society is that you can now tell someone's socioeconomic class after hearing them speak only a few words. In effect the society has now become linguistically stratified, and LC is what makes that possible. The irony is that while there's nothing intrinsic about LC's culture or content that makes it appealing, the unexpected side effect is that native born teachers of LC now become very wealthy and influential, thus sending an unexpected infusion of money and power into the LC community. [Answer] We need to take a lesson from the modern-day United States, which is slowly adopting Spanish. Whether or not the U.S. will completely adopt Spanish is not what I'm talking about. We're in the process. We're not printing government pamphlets in English and French or signs in English and German. We're slowly adopting Spanish. In many areas (possibly most, I'm not that well travelled), you'll find (E.G.) signs in Home Depot stores that are English with Spanish small print. As you get closer to the southern border, those signs change to Spanish with English small print (might not be common, but I've been in such stores). Why is this happening? Because the influx of the Hispanic culture has reached a critical-mass point where commercial interests, educational opportunities, and government services are impacted by the ability to reach people who don't speak English (well or at all). It is bolstered by a growing sentiment that all people should receive those benefits (commercial, educational, and governmental). And the perspective is important. Even if the goal is to teach (for example) Hispanic children English, you still need to communicate with them. That means the teacher's job is easier if that person speaks Spanish. The shop owner may appreciate what little English they know, but he can better sell goods if he/she knows Spanish. Etc. It should be noted that while I use Spanish and the Hispanic culture (as the largest of the ethnic sub-groups), we see this behavior everywhere where any ethnic group has become a substantial fraction of the whole. Walk through San Francisco's Chinatown and see how much English you can find. Walk through any of the Jewish or Amish communities and see how much English you can hear. Locally, this behavior is more common than we might think. Conclusion The social forces are: 1. The persistance of a tolerated sub-culture as it grows in relation to the dominant culture. 2. The increasing relevance of that sub-culture as a participant in government (whether it's reception of services or as a represented voting block. Your actual government structure will modify this.) 3. The increasing need by society to incorporate the youth of that sub-culture into its socio-economic structures. This is complicated, but it includes both buying power and store ownership, community leadership and community protection (think police, fire, medical, etc.), and the military. If 20% of your military volunteers are of a particular sub-culture and their contribution is valuable, speaking their language becomes critical. 4. The increasing desire to ensure meaningful citizenship of the sub-culture through education. 5. Finally, the willingness of the dominant culture to accomodate the sub-culture, to welcome them and make them equals. [Answer] By The Sword The BC's have become soft by the wool of civilization. They have not known war for generations. Their generals sleep in silk sheets, their boys pick up the brush over the spear. Their army is a bureaucratic mess, little more than a daycare for perfumed nobles to offload their extra sons. Their officers buy their post with gold rather than the currency of blood and valour. Unlike them, we have been fighting since time immemorial. The soil is poison, what little that is grown must be protected with iron and will. Every boy is taught the way of the sword, the land is hard and it's people must be harder. A path has been opened up the mountain. The lands beyond are rich and fertile. The drums are beating, the warchiefs gather, they have elected a chief among them. Us who have slept on hide and granite will have sons who will sleep on silk and satin. By The Harp The BC's tongue is harsh, there is no music in their language, no complexity for the emotion and depths of our epics. We Teyarzhaodaquan are rich in nothing but the music of our voice. We sell our songs to the nobles and poor alike. Our troubadours travel the depths of the kingdom. On every fishing village, border post and manor we stop and share our songs. The children copy our mannerisms, our sayings. The learned copy our tongue, our letters. The demand for our stories are such that books are written in our speech so that one may hear our story even where our troubadours cannot go. It is not long before they abandon their own tongue, it has become the trend to memorize our songs, it becomes the cultured thing to do. People who cannot reference our songs become the rube and ignoramous. The rich compete to see who can speak our language the most fluently. The old speech becomes the tongue of the vulgar. The vulgar, always wanting to become more than they are, abandon this too. In every corner of the country, a baby falls asleep to an Teyarzhaodaquan lullaby. [Answer] A larger dominant country is never going to replace their language with the language from a smaller inferior country. However a larger dominant country might from a smaller superior country. If you look at the world today, English is the language of science, the internet, computers and commerce so even in places like China and India with massive populations and their own native languages, English is pushed in the schools. If the smaller country has superior education facilities, banking institutions, markets and trade routes, the larger country may send their young to be educated there. Suddenly the upper class in the larger country now have the ability to speak the language of the smaller country. They teach their children the language in preparation for their own education. The middle classes want to learn the language to give their children the chance to move up classes or at least work directly for the upper class. Eventually everyone is learning the language. [Answer] From the Top Political Marriage is a common approach to brokering peace and absorbing other nations with BC, however generally speaking only one or two marriages are necessary. For whatever reason, the leadership of LC has demanded that their dozens and dozens of unmarried elites be married as part of this. The result is that across the upper strata of BC, most of the young nobility are now married to people who only natively speak LC's language. The usual convention is that the newcomers learn the language and most likely their spouse learns their language in turn, but in general the language takes a back seat with the sheer scale of BC gently compelling conformity.. Not so now, those new husbands and wives from LC can talk to each other and there are so many of them the language remains strong amongst the upper echelons, their BC spouses scramble to learn the language. Of course it's a far more elegant and beautiful language than BCs speech, so it soon becomes very trendy to be able to speak it, similar to the way french aristocracy marrying into the british royalty brought their language in the 1700s/1800s (note: my history is shaky on this one) Soon enough any educated person is able to speak LC, and with the strong continuing presence of native speakers who teach bilingually to their own children, the language continues to filter down and becomes the defacto High-Class language of the nation. Anyone who is Anyone speaks it fluently, everyone else is inconsequential peasantry. [Answer] LC's usefulness as a formal language It turns out that LC's language, in spite of all it's complexities (or maybe because of it), is a perfect fit to be used as a [formal language](https://en.wikipedia.org/wiki/Formal_language) for BC's science and technology. While hard to learn, it makes interacting with BC's computer-like machines and interfaces a breeze. It helps BC's scientists to clearly and concisely describe complex problems and their solutions, something that, while possible, would be a lot harder to do in their native language. As such, LC's language becomes a mandatory part of any curriculum, not well liked at first but at least accepted for it's obvious usefulness. Now the BC's version of the internet comes online, and becomes all the rage with the younger generations who all had 'LC' in school and are now using it as the defacto language of BC-net. This sets the stage for the process that slowly but surely replaces the original BC language with the 'new' LC language used by the 'BC-net generation' and their offspring. For real life examples i'd look at the way English is becoming a second (nigh first) language for the 'internet generation' in European countries. [Answer] Money talks They may view the smaller country as inferior, they may or may not hate LC guts and everyone in it but one thing BC can't deny is that LC is loaded, it may be that they have gold mines everywhere or it may be that they are located at the center of the "silk road" of the area and a lot of commerce goes through it but whatever the reason is LC is really really rich. The folks of BC might not like the folks of LC but they sure do love their money\gold, and the best way to make business with someone is to speak the same language as he does, over the years the people of BC started doing so much business with the people of LC that LC language has become the de facto standard language of BC. [Answer] ## Administration LC has always had a small population and few natural resources. The only reason they have survived so far is because they are ruthlessly efficient about everything they do. Even during the conquest, despite superior strength and numbers, BC has learned just how efficient their logistics were. LC's militians, militians!!!, never went hungry, always had the appropriate gear, wounded were tended to and evacuated, and the units seemed to coordinate their movements effortlessly. The resistance may have been futile, ultimately, and their tactics were not so great, but the strategists of BC were left in awe of the logistics. And once they finally got their grubby paws on LC's weak government, they discovered its administration. They worship stone indeed, and commit everything to stone. A detailed history, in each town, reaching centuries back down to the founding! Indexed and organized in a way the best librarians of BC would never dream of, and at a scale they've never seen. A well-defined set of responsibilities for each branch of the administration, with well oiled channels of communications so that not an ounce of gold or silver is unaccounted for, genealogy for centuries, possession of lands and noble privileges linked to the very act of law which enacted them, etc... --- The king of BC is no fool, the generals see the potential immediately, and so they attempt to learn from the example... but it doesn't work. The very worthless culture of revering stone is what leads LC's people to only ever commit truth to stone, and to commit it in extensive details. Their very difficult language is due to the combination of precision and succinctness that those faithful records require. Attempts to mirror this greatness fail, repeatedly. Attempts to commit the lyric and flowery language of BC to stone fails too: the stone cannot capture the necessary details, the fluidity of the letters, and worse the flowery language just takes too damn long. So, resigned, the king has no choice but to take on the very administrators and scribes from LC, and let them use their own primitive language for the task; for it is as primitive as stone, and perfectly fits the medium. Of course, letting the conquered record in their own language without supervision is unthinkable, and so the scribes of BC, promoted task masters, must now scramble to learn this primitive language they mocked. And the new scribes are taught this language too. And soon, since it is so inefficient to translate back and forth, with all the imprecision this entails, between the written tablets and the oral language, administrators start using this language to talk to the scribes, and then to talk between themselves. Would a noble trust their administrators blindly? Obviously not. Would a merchant trust the tax collector blindly? Obviously not. And so, little by little, the elite of BC learns the intricacies of LC. Two generations later, the administration of BC is entirely conducted in the former language of LC; and it is well known that requests expressed using the common BC stall, due their imprecision, so communication with the administration is itself using the former language of LC. [Answer] # It's never going to happen The language in question has no significancy to anyone but the people who already speak it. There is simply no reason for any adult to learn the language, except as a curiosity or to speak to the primitive people with the hard to learn language. This should already make it abundantly clear that the language will never take over as the official language of another country. ## Military conquest to spread the language The BC nation is, in every way, superior to the LC nation when it comes to miltiary might. There's simply no way a mideval army of any size is going to defeat a modern army. The primitive army is severely hampered by logistics -- once it grows beyond a certain size, it cannot keep enough supplies around for the army to be effective. Adding the problems of disease and malnutrition in this kind of army, when it's effective, simply means that they'll never be able to defeat a modern army. The modern army will simply retreat in their vehicles, while moving the primitives down with their flamethrowers, machineguns, grenades and poisonous gasses if they ever get into trouble. Or just by dropping loads of bombs on them from airplanes or shelling them with their massive artillery cannons from 20 kilometers away. No defenses the primitive army can create is going to a challenge for the modern army. Even a single squadron of modern infantrymen will be able to defeat anything short of a full blown castle. Adding tanks, planes and artillery, means there's no chance that the primitive army will every make a dent in the modern army. Completly destroying the primtive nations economy is going to be a piece of cake. Torch every field they find or drop land mines everywhere and the primitive nation is gone with no hope of recovery. ## Spreading through culture is a dead end It has been suggested that spreading the language through culture might work, but I (clearly) disagree. Spreading the language by writing songs and books may work for a short while, but it will never be able to take over a country where another language is already ingrained in every part of the country; such a country will have a very high degree of connectivity, meaning any change will have to work through a massive amount of inertia; you will have to change most things at once to make anything stick. ## But there is hope! It cannot happen in a short timeframe, but it may happen on a very long timeframe. Given that the LC people has no reason to adopt the BC language, the LC language will remain free from any major influence from the BC language. If the BC nation where to splinter into many fractions, some of the weaker ones near the LC nation, the LC language may gradually take over neighbouring regions. This could, very slowly, spread the language over centuries to the point where a unification of the BC fractions would make the LC language the major language of the BC state. This is a bit of a stretch though. Besides a few minor languages that where dominated by already major established languages, I cannot think of a single example where something similar has happened in real life. [Answer] When the first people from BC arrive, they survive the dangers you outline solely due to the assistance and knowledge of the LC peoples they encounter. Learning the language is a matter of necessity. Translating the terms necessary to ensure survival with enough precision to enable survival is cumbersome and time consuming, precisely because of the language traits you described. Therefore, anyone from BC who travel to LC need to have at least a basic level of fluency in the LC tongue. Obviously, there is something worthwhile in LC, or the people of BC wouldn't bother after the initial trip. It could very well be the materials made available by those very dangers. If harvested, they could be put to great uses through the superior technology of BC. In the process of using and refining these materials, the terminology will spread throughout the BC language, and eventually everyone in BC will have at least some degree of understanding of the LC language. Eventually, a superior fluency in LC's language becomes a sign of education and/or wealth, causing its use to become common among the elite, and eventually filtering down to the lower classes as well (since they need to be able to understand the upper classes when they interact). [Answer] In your question you have carefully excluded all potential reasons (number of speakers, technological and military advantage, cultural advantage, easiness, e.g., usability as a bazaar creole for traders, and even magic) for the big country to adopt the language of the small territory. It will not happen, just as the USA won't become a Navajo speaking country at any time. [Answer] I just happened to be passing, and VL;DR - (very long, did read). Seems the governing factor for humans is that we learn our language(s) before the age of reason (whenever that might occur). And after that, acquiring another is hard, lengthy work. So when you're positing a large nation adopting a new language as an "event", it's a highly unlikely event. Examples mentioned already - Chinatown, Amish, etc -demonstrate that if we can keep using our native language for daily life, we won't go to the trouble of learning another without a powerful incentive. [Answer] A Secret plot to conquer neighboring countries. The leaders of Aeðsta wish to conquer some neighboring countries without trouble and be able to occupy them for decates or longer. Thus they will learn the language of the vassal state Teyarzhaodaqua, promote some of them to high ranks in their military, feign being overwhelmed by a superior stratagem or magic, resulting in conquest of their own and the other nations. Then the true leaders of Aeðsta throw off the yoke of Teyarzhaodaqua and "liberate" the other countries, but insist on stationing troops there to keep the beguiling invaders of Teyarzhaodaqua from returning in a second wave of conquest. Sounds like the "Great Game" of Europe, no? [Answer] When the soldiers of BC's fleet set foot on LC's ground, so does the very first linguist BC has ever sent into LC. After observing the people for some time, he recognizes the prophesied sign of their own god in LC's language. Suddenly everyone wants to learn the complicated language as a sign of worship and enduring hardship for their god. Clerics are the first to only speak and preach in the complicated language, so even the socially lower people learn by exposure. Teachers that speak LC's language are in high demand on the most prestigious universities and the rich and noble are the first to send their children to such schools in order to raise them in the light of god. This trend trickles through to the lower social levels and in no more than 2 generations the old language of BC is only taught to those who have to understand the historical records. [Answer] The ancient texts You mentioned that BC had posesstion of some ancient texts that they thought LC might be able to translate. The problem for BC is that LC doesn't want to make peace with the weak, rock-worshipping people on the other side of the mountain. Because the people in LC are small in number and have a complex language, it would be easy for them to keep their language from anyone in BC who wants to learn it. However, LC has been blessed by their light god(s) with a vision of a world in which all of BC worships the religion of the light. Because the religion in a country weakens as sciences and technology advance there, BC's motive is not religious, they think the texts can help them either advance their civilization or defeat LC. So BC and LC make a reluctant deal: The deal In order for BC to translate the text and know that LC isn't making up some random translation, at least one person from BC needs to be fluent in LC's language. In order for LC to convert BC without conflict (which LC would never win), LC needs to teach BC about their religion and culture. What better way than with language? If people learn LC's language, they will also learn about LC religion. Once they see that light is clearly superior to rocks and convert, the good(s) of LC will bless them with good fortune and gifts. BC makes learning LC's language mandatory. A native speaker from LC teaches someone from BC the language a little at a time, and using their modern communication, that person teaches everyone in BC at the same time. By the time BC deciphers the texts, most people are knowledgeable or even fluent in LC speak. Adoption of LC's religion soon follows, and the nations soon form a strong alliance based on mutual worship of the light. BC gives LC the luxury that their people have only dreamed of, and LC teaches BC how to worship the good(s) and make sacrifices. Now a need for something the other country has is turned into a mutual love of the light culture. Bonus: the text provides some valueable information that makes life even easier for BC and they can share all of the newfound wealth with LC. [Answer] WW2 the US adopted Navajo native Indian language because it was very hard to decipher and played a major part in winning the war. ]
[Question] [ So it turns out the universe is a computer. Or at-least that is how it can be analogized to our puny mortal minds. Human souls/consciousness are simultaneously the equivalent of emergent AI, players, and the dissociated fragments of the universe's creator depending on what theological interpretation you subscribe to. Some souls, via lots of hard thinking and calculation, can start to notice this and can add some of their own code to make things interesting. It's a fairly popular set up, and the topic of a magic system based off of mathematics and computer science is something I've read extensively about on this site. However one issue with this set up and analogy is that it usually runs on an ad-hoc limiter. Mana or some kind of FP bar. A limited resource, typically sourced from a living thing or 'soul', that in order to run a spell, has to be expended. But that's never entirely sat right with me. When I played minecraft as a kid, there were artificial limitations imposed on my resources. But I could also easily mod the game or just use command lines to move super fast, fly, alter the weather, daytime, or create new resources ex nihilo. There technically shouldn't be a limit to how many spells can be spammed. Wizards could spew as many fireballs as they want. As the fireball spell already sticks a middle finger to thermodynamics. There's plenty of energy to go round afterall. So if the universe is a computer, magic is programming, what exactly is mana supposed to be? Why do my metaphysical script-kiddies tire out after the tenth fireball? [Answer] In this cosmology, envisioning mana as akin to the computational resources - CPU time, RAM, or other crucial system components - that a sentient program or a fragment of the universe's architect can leverage provides an apt analogy. This analogy becomes particularly pertinent given that these resources are finite. If a program could monopolize all available system resources, much like an infinite loop scenario, it could trigger system instability or a potential collapse of the universe, our cosmic "computer". Thus, there is a critical need for resource allocation boundaries for each sentient program or soul to maintain universal stability. Mana is the term we're using for these allocated resources. When a program exhausts its mana allotment, it must endure a mandatory latency period for resource replenishment. This regulation safeguards the universe while also providing a strategic and endurance test for the sentient programs. Using mana as a metaphor for system resources brings a unique equilibrium to the power dynamics of the sentient programs. It prevents any one program from becoming overwhelmingly dominant and potentially threatening the stability of the universe. It also tests the strategic acumen and resilience of these programs, forcing them to intelligently manage their mana to strike a balance between their will to manipulate their surroundings and the risk of resource depletion. The depletion of mana could lead to the sentient programs experiencing significant physical and psychological strain - much like a computer experiencing a system crash due to resource overload. This is because, when a program's mana is nearly depleted, the program starts utilizing its own physical and mental matrix as a substitute for mana, a mechanism reminiscent of the body consuming itself during starvation. Each spell cast, each fireball thrown, is a line of code, a command that drains a program's mana. If a program does not manage its resources effectively, it runs the risk of burning out or falling into a state of temporary magical impotence due to extreme fatigue. This level of realism in the mana system introduces a challenging dynamic into the practice of magic, echoing the real-world limitations and challenges in computing and programming. [Answer] Every computer should have an antivirus. Programs or systems looking for anomalies, anything that doesn't follow the the code (natural laws of nature), and deletes it. So mana in this case would not be a hardcap, a fixed upper limit for what you could do. But a limit for how much alteration you could do before Mr. Smith (Matrix reference) comes looking for you. Such a cap would be the same for everyone, though it might differ depending on location. But some people might be able to use it in a clever way. For instance if you create a large fireball, that's a large anomaly. But if you crack a gaspipe running under the street and ignite it, it's still a large explosion, but a much smaller alteration to the natural laws. [Answer] # API quotas Nothing in business is free. When you are playing Minecraft on your PC you can mod costs away, but when you hire cloud services on the internet such as Azure, Amazon AWS, MongoDB storage etc. you pay for usage. It's usually done on a basis of an x amount of USD per y amount of data stored or transfered, z amount of calls to an API or whatever amount of virtual machine online time. As far as I remember, for example, if you use the Google Maps API on your site the first 100,000 calls per month or so are free, then any extras only go through if you pay up and there are levels of membership with different limits. Actual numbers and costs vary over time. So take a page for that. Whenever you cast a spell, you spend a certain amount of [ManaCoin](https://worldbuilding.stackexchange.com/questions/112309/what-can-be-used-as-a-money-in-a-high-fantasy-magic-world-where-noble-metals-are/112321#112321) to pay up a little magic elf to actually do the spell for you (or something like that), with the costs varying by spell and how they are used. [Answer] ### Focus > > Some souls, via lots of hard thinking and calculation, can start to notice this and can add some of their own code to make things interesting. > > > I'm a programmer in the real world and I can tell from experience: Focus is my limitting factor. When I have good focus, I can grasp more complex issues, think ahead more, think outside the box better etc. When I dont have good focus (eg bad night sleep) my performance drops. Automatic pilot takes over, I'm overwhelmed a lot easier. My ability to perform difficult tasks decreases, I become more sloppy. My programming is already natually limited, by Focus. And sure, you can train focus, I can force myself into somewhat of a concentration-state when I have a bad day, this is a trained skill, but that does certainly have its limits. If you need a reason they dont program more and more focus into themselves, all AI have a specified amount of resources. If the human/AI reaches that, thats it. You can optimise and use it more efficient (eg training, practice) but it will limit. [Answer] ## Magic is an in-game System, not a Hack Mana makes a lot more since when you view magic as an in-game programming interface. The reason it feels like programming is because it works that way by design. Wizards are not actually accessing the simulation's base-code, but rather a framework that runs inside the game for the purpose of building spells. So a scroll of firewall might look like this: ``` function fireWall($size, $heat){ $fireEffect = new fireball(); $fireWall = $fireEffect -> burn(); $fireWall.range = 5; $fireWall.length = 1; $fireWall.width = $size; $fireWall.height = 5; $fireWall.heat = $heat; $fireWall.burn.time = 60; return $fireWall; } cast fireWall(25, 500); ``` As you can see, the wizard can programmatically build a spell but it's all based on in-game spell classes. While a wizards can pass all sorts of parameters to a spell class, these spell classes are hard coded into the game, and can not be modified. Each class contains in it, rules for how mana is expended to cast the spell. Since the system has no way of creating an effect in the simulation without calling a recognized spell class, there is no way to write code that has an effect without spending mana to caste it. So in the case of the above firewall spell, a wizard can customize one spell to make something totally new, but it must follow the same mana cost rules as the original spells because these classes don't accept "manacost" as a parameter. ## Why unlocking magic takes so much "hard thinking & calculation" There are 2 possible reason why you'd have to be really cleaver to unlock magic. Option #1: It is an exploit. It's possible that the Great Developer created the magic system, decided he did not want it to be part of the game yet/anymore, and tried removing it from the game by deleting all of the pointers to it. So, while it is theoretically dead-code, there may be an in-game exploit that unlocks it because the Dev missed a pointer in some obscure and forgotten function; so, through critical thinking and by doing something very unexpected, wizards can exploit thier way into the magic system. Option #2: Magic is a level locked ability. If you are an out-of-shape couch potato, chances are you can not do a backflip or a chin-up. I don't mean you can't do them well, I mean you literally can't do them. It takes all sorts of other strength training to get up to the point were you can even do certain things badly. So these are like level-locked abilities that require you to build up to a certain strength level to even try. Well, magic is a level-locked ability for your mind. Until you develop a certain level of logic skills, it's something that you can't even sort of do. So, you have to learn a lot, and practice your intelligence in other areas before the laws of nature will allow you to "open up" your spell-scripting interface. [Answer] Similar to the other answers - but in most enterprise grade Cloud systems (Azure/AWS/GCP etc.) Every consumable resource (Read/Writes, CPU time, RAM, Data ingress/Egress etc. etc.) is charged for. Now - firstly - it's because the big mega-corps don't want to be giving out any freebies, but on a more practical sense, it's to stop abuse. I've seen a poorly secured Azure account compromised and a spammer spun up a large number of very expensive VMs to do CryptoMining. Which is essentially what you are worried about - people abusing the system. For each 'tier' of plan, you get X number of resources. Sometimes, the resources are amalgamated into a single unit - for example for Azure SQL, there is the concept of DTUs (Data Transaction Units) that is specific to SQL, it's a combination of the CPU/RAM/Disk/Network/Power requirements to transact a bit of Data (duh...) So. All that written - let's now make it into a Magic System. First and foremost - you will want hard limits - no one can access more than X at a time - we would call this a Rate Limit - and even in enterprise grade environments, there are upper hard limits (that is, limits that no matter how much you pay or how nice your account manager is, you can't exceed). Below that, everything has a price. How do you work Price into your system? Well... I would suggest that the Users Skill and Favour is how you would balance this. Skill is self-explanatory. The more skilled the Wizard, the more efficient they can be with their resource usage. E.g. a Novice might need 100 Mana (which is in effect, like a DTU) to cast a Fireball, but an Expert Fire Wizard might only need 20. You can justify this in that the more advanced the wizard, the greater their 'Code' is optimized. Favour is where it gets fun. Think of it lik Stack Exchange Rep - if you do things that are percieved as good (or at least are rewarded by the masses as good...) then this increases your Favour - this allows you to access more than the average. This isn't a formal system, it's based on Magical/programmatic perception. A Fire Wizard sees a young boy freezing to death in a lake, they use their fire magic to rescue and warm them up - the Boys family and a few onlookers think 'Gee! That Wizard was very nice' - they've just up-voted that Wizard, like we upvote questions and answers here or on Reddit or Twitter or... Conversely, Our same Fire Wizard sees a Forrest Fire happening, he decides to create a fire break, by magically burning everything in a 100 metre wide gap, but that includes a few peoples homes. Lots of people are grateful that he stopped the Forrest Fire, but the people that lost their homes are still angry - this is like a controversial answer that has a lot of up and down votes. Then, we find out our Wizard has been doing this all for a Ruse and goes out and burns a village to the ground - this would be like a massively ratio'd post/answer and if it's bad enough, they'll be dropped down to the lower tier. [Answer] ### Unintended redirection of computation power The universe is a computer. Or rather, a lot of small computer-like units, grouping together to emulate different aspects of reality. You need more units for certain tasks, depending on their size and complexity, but overall anything can be reduced down to their "personal" swarm of emulation units. Now, what would happen if someone started to graps this concept, and even managed to influence the units emulating them? You get a wizard. "Magic" is really the art of rerouting the computation power of your own units to other means. Releasing one or two routines of your existence for a few moments, in order to do something new. Each person makes it work in a different way, and it can have many different forms, effects and potencies, but the concept stays the same. Some people may do this by releasing one of their 5 senses during the casting. More reckless casters could even stop major functions, like breathing, or even their blood flow. When you see that person closing their eyes, it isn't just for show, they're "turning off" their vision to reroute its computation power into a powerful spell. Why is this person so tired after casting fireballs? Because they've been releasing their control over some parts of their body, putting more stress over it just standing still. Heck, some people with permanent conditions may even be able to continuously use magic. This deaf person? Since they cannot hear, they have a part of their unit swarm permanently available, meaning if they notice it, they could cast powerful magic just about all the time. Even in this case though, a unit is a unit. If overexerted, it can overheat, meaning that the most powerful effects still cannot be used over and over without some cooling down. Except... If you can get access to something else's units. By default you only have access to your own units, for security purposes. After all, if you could just rule over any unit you know about, you could just use this chair's units, or even your "friend", potentially sacrificing them in the process. But what if there were hidden access panels? Debug panels, or other control nodes, hidden deep within specific swarms of units in remote locations. Panels which, if accessed and studied well enough, could grant access to other swarms of units. In the hands of the wrong person, those Panels could bring destruction like no other, since you could have individuals essentially capable of spamming spells with practically infinite mana. This model brings the following : * An explanation to "mana", why it is limited and why you can't just siphon someone or something else's power. * Individuality in each wizard's "mana pool", the way they channel it, their limitations when casting spells and so on. * A [MacGuffin](https://en.wikipedia.org/wiki/MacGuffin) in the form of objects or places granting access to what is essentially infinite mana and/or knowledge about the true nature of the universe, as well as ways to use units in different, more potent ways. In the end, though, "Magic" as practiced is an unintended use of those units. Overusing your swarm of units in unintended ways could have unforeseen consequences. You could even go as far as to make the "creators" of the universe intervene in the events that the universe is made too unstable by those "exploits". [Answer] Electricity Electricity is what makes the hard drives work. It's what makes the monitor light up with pretty colors. It's what makes your XBox controller shake and what makes sound. And if you don't pay your electric bill... your computer stops working. There are all kinds of limiting resources when you think like a programmer. Clock cycles, CPU throughput, backplane capacity, memory... my favorite is IRQs. Those little honkers have been around since, what, the Intel 8086 or before? But in reality, none of these are consumables. In terms of your metaphor, they represent what limits the complexity of a spell or its power... but they're not the primary consumable you call Mana. Electricity. Every other limitation still allows you to write a useful program. But without electricity, you're only option is something horrific like a Babbage difference engine. But at that point you don't have programming of the kind you're thinking about. Yeah. Electricity. [Answer] ## It is Gas Spells require computational processes, and the Universe has a limit on that resource. So in order to prevent users from abusing the system and expending all of the processing, the Universe Virtual Machine applies Mana fees that must be paid to execute spells. Copying for Ethereum org: > > Gas is essential to the Ethereum network. It is the fuel that allows it to operate, in the same way that a car needs gasoline to run. > > > [...] > > > Gas refers to the unit that measures the amount of computational effort required to execute specific operations on the Ethereum network. > > > Since each Ethereum transaction requires computational resources to execute, each transaction requires a fee. Gas refers to the fee required to execute a transaction on Ethereum, regardless of transaction success or failure. > > > Emphasis mine. [Source](https://ethereum.org/en/developers/docs/gas/) If you follow this logic, you can even do some interesting things. For example, in the Ethereum VM, you can pay extra (called Priority fee or tips) so your transaction is executed with priority. In your world, wizards could spend extra mana to override other spells. [Answer] ## Computer Science Calls This “Fuel” Alan Turing famously proved that it is impossible, in principle, to prove that an arbitrary program halts, and Henry Gordon Rice extended this to prove that all non-trivial statements about an arbitrary program’s behavior are undecidable. So, what do systems that want to be sure they don’t follow a dead end forever, do? They add a “fuel” parameter to their algorithm, the number of steps it is allowed to run, and subtract 1 from it at every step. When the fuel reaches zero, the algorithm is forced to stop. This could actually be voluntary on the part of the casters: they’re warned to put in this kind of kill switch, lest their spell run out of control, but that’s on the honor system. It also implies that spells last arbitrarily long, but not forever. If it’s enforced by the environment, it becomes very important to write spells that do as much as possible as efficiently as possible. [Answer] I was somewhat surprised that these words are not in others answers, but: ### Quantum fluctuations The [thing](https://en.wikipedia.org/wiki/Quantum_fluctuation) that makes black holes [not so black](https://en.wikipedia.org/wiki/Hawking_radiation). It's a "local finite" thing, it's auto refreshing non stop, and it is absolutely present everywhere, even in "empty" spaces. Normal nature is when the quantum fluctuations are disorganized static on TV tubes, and magic is when these fluctuations are organized into a coherent-directed signal that produces some image in the said TV tube. In other words, magic is the computation process that [quantum tunnels](https://en.wikipedia.org/wiki/Quantum_tunnelling) transform the quantum fluctuation state mana in one space, and at same time, change the very nature of that space. Air becomes plasma, and static plasma becomes moving plasma. But the thing is that mana is a very tricky thing. It's small, it's unstable, and it will cause change. Magic users can do so much, without destroying yourselves. And so, it's very tiring for anyone to actually make this happen. A lot in magic making is about chasing some specific output while [avoiding some other results](https://hitchhikers.fandom.com/wiki/Infinite_Improbability_Drive) at the same time. [Answer] ## Raw data? The type of spell is defined by the end outputs or results specified by the program (spell) in question, the type of data input and, to an extent the complexity of the programs impacted. Spells can either make changes to preexisting data to cause temporary effects e.g a teleport spell re-writes location data of a person (program) but changes no innate programming. Such a spell requires raw input data including the spatial data on the current and intended locations of the object or person being teleported. A permanent effect spell, say transmuting lead to gold is more difficult but can be permanent or at least long lasting because the program defining the object being transformed has to be precisely altered. This also requires input data on the location and nature of the object but also data on what the object is to be turned into. The power of the spell is defined by the amount of data to be input, the rate at which data can be processed in a given unit of time and, to an extent the complexity of the program. The input data used as inputs for the spell is extracted from the universal memory of creation in which All data and programs in the universe are stored BUT (and this is important) the underlying programs of the universe include RAID controllers and related programs. These act to both maintain the underlying stability of the master program (the universe) and to format, compartmentalize and preserve important data. The output data is the impact the spell has on 'reality' i.e. existing data sets and programs. The output data is an overwrite of preexisting data and programs caused by the spell. In the event the conditions listed below aren't violated this can now become input data for future spells and is stored in the universal memory as such. The result is that there are limitations imposed on magicians/priests etc. These include but (depending on your wishes) may not be limited to: * access time; needed to locate and extract the data from universal memory * limitations on data manipulation. Spells are innately limited in both size and the ramifications of their impact because the universe tends to overwrite and return the universe to it's previous 'normal' (default) setting rapidly in the event a spell significantly destabilizes core underlying routines, settings or programs. So casting a fireball quickly is one thing (the universe barley notices). Write and activate a spell designed to say make the Sun go nova? Not only is the amount of input data required enormous (requiring in turn huge amounts of time and effort to locate and extract) but activating the spell immediately causes so many changes to the Universe that self protection re-writes kick in. So when executed the 'nova' spell appears to fail. In reality it worked but the output data causes such severe and widespread changes to the starting conditions and programs that the results are immediately deleted and settings restored to the prior universal positions. [Answer] Obviouly computrons. > > computron: /kom�pyoo�tron`/, n. > > > 1. [common] A notional unit of computing power combining instruction speed and storage capacity, dimensioned roughly in instructions-per-second times megabytes-of-main-store times megabytes-of-mass-storage. “That machine can't run GNU Emacs, it doesn't have enough computrons!” This usage is usually found in metaphors that treat computing power as a fungible commodity good, like a crop yield or diesel horsepower. See bitty box, Get a real computer!, toy, crank. > 2. A mythical subatomic particle that bears the unit quantity of computation or information, in much the same way that an electron bears one unit of electric charge (see also bogon). An elaborate pseudo-scientific theory of computrons has been developed based on the physical fact that the molecules in a solid object move more rapidly as it is heated. It is argued that an object melts because the molecules have lost their information about where they are supposed to be (that is, they have emitted computrons). This explains why computers get so hot and require air conditioning; they use up computrons. Conversely, it should be possible to cool down an object by placing it in the path of a computron beam. It is believed that this may also explain why machines that work at the factory fail in the computer room: the computrons there have been all used up by the other hardware. (The popularity of this theory probably owes something to the Warlock stories by Larry Niven, the best known being What Good is a Glass Dagger?, in which magic is fueled by an exhaustible natural resource called mana.) > > > source: <http://www.catb.org/jargon/html/C/computron.html> ([The Jargon File, a public domain document](http://www.catb.org/jargon/html/online-preface.html)) It's interesing that there's a reference to mana there. [Answer] Garbage collection. The universe is a simulation. Every program (i.e. person) is assigned resources when it starts. Magic is a workaround/hack/exploit - which means that it uses resources that were intended for other things. Unlike regular "clean" code, these don't get freed up immediately - because magic is a hack. Over time, garbage collection will eventually free this RAM or CPU or port locks, etc. up - which is why mana eventually replenishes. It's also why getting a good sleep helps replenish mana, because sleep is where the system is running most of the garbage collection. A regular activity would be written with an allocate - use - free cycle. Magic being a hack is more of a steal-from-somewhere - use - drop-without-free cycle. [Answer] ## You're spending your own allocated system resources. An individual entity in Simulated Reality is permitted a certain amount of system resources to do what it's meant to do. A rock requires very little beyond the purely physics-based simulation. A person requires substantially more to simulate a mind and memory and all manner of other things, and there's some margin for doing more mental heavy-lifting. With that in mind, a wizard casting spells must use their own allocated resources to do so. The upshot is that casting spells maxes out the resources-per-cycle they're supposed to have very quickly. The simulation isn't just going to lock up because some process is over-simulating though (There's no shortage of system resources, this is just a management thing), instead the person gets.. throttled.. Their system-resource allocation is reduced until they stop over-using it. They're in debit with the universe until enough time passes without continuing to cast spells that it wears off. This can manifest as tiredness, fuzzy-thinking, an inability to stretch past the bounds they're supposed to be able to manage (eg: They can't cast more spells) and in extreme cases, they get knocked unconscious because their system-resources for thinking are overstretched. The most extreme case is that they die because the resources aren't allocated to allow them to keep their heart beating and lungs pumping, and once they die, the system won't replenish them so they can wake up again. A common wizarding malady would be "Mage-Brain", where having begun casting spells, you aren't thinking clearly anymore. Which tends to manifest as a kind of drunk-with-power effect. Mad laughter, that sort of thing. Meanwhile, many schools of wizarding advocate all sorts of Mental Discipline and Zen states. They believe this puts them in better contact with their magic, but the reality is that by thinking less, they have more system-resources to spend on magic.. Thus a beautiful paradox. To be a wizard, you have to be smart, but once you are a wizard, you become entertainingly dumb [Answer] Entropy. As things stand, any computation increases the entropy in the immediate vicinity of where it is carried out, which conventionally becomes heat which has to be removed. Certain locations are either at a (temporarily) lower temperature so can support a brief spurt of high-intensity computation before becoming (temporarily or permanently) unusable, or have better heatsinking so can support sustained high-intensity computation. In either case raw energy has to come from somewhere, and lower-grade energy i.e. heat has to be disposed of somewhere. These might be parallel universes, possibly inhabited: The Gods Themselves know :-) But certain people might be able to harness more efficient means of computation, see <https://en.wikipedia.org/wiki/Adiabatic_circuit> as an example. A lot depends on whether the "gates and circuits" are some property of the Universe (i.e. some sort of computational substrate), or are a property of or carried around by a player or NPC. [Answer] Syntax and API knowledge, Time, Energy, clear mind, typing speed and logic. The more you have the more you cast good lines of code. But the universe is still universe cause programming is not code execution. If you are talking about running code = magic then mana is computer ressources the more you have the more code you can run. [Answer] ## Nanomachines Reality is permeated by them, and they recharge slowly on their own, but they use energy to build and shape reality to the whims of magicians (programmers!). Some spells are more "costly" than others requiring more nanomachines (NM) to "cast", and stronger wizards are able to hold/accumulate more fully charged NM, allowing them to cast more powerful spells. Some areas of the world have more or less NM in the ambient environment making it easier or harder for any mage to cast by drawing from their surroundings, in extreme cases (think a clean room) there might be no NM nearby meaning a mage could be severely limited in what they can do as most of the time spells rely on a mages "personal" NMs forcing cascading changes in the ambient NM to enact spells, and in low NM areas the biggest spells might not be possible to cast. For opposed spell casting it comes down less to raw power, and more in ability to "convince" the ambient NM to work for your spell as opposed to your opponents. Similar to escalating battles between virus/anti-virus software whomever is able to better maintain control of the NM in an area will most likely ultimately win in a magical duel. And of course, the slightest mistake can have catastrophic and unintended consequences just like programming computers in real life. Spells do exactly what you tell them to, which might not be what you wanted them to do, especially as most wizards don't actually understand programming, rather have learned it by rote. [Answer] Awesome question, thanks. I’m working on a world that hinges on some of these questions. If your world-building demands for the magic to be based on a computational resource and for the magic users to have direct access to the simulation code repository, one way to restrict the magic is to require forking the main repository into an isolated side branch, making the desired changes (the magical effects) there, and then merging it back into the main branch to cause the effects to happen in the “base reality.” That could be limiting because you need to checkout, write, pull, merge either cognitively (which can be massively tiring) or due to design constraints (like needing approval for your pull request). However, this may be a narrow issue. For this to be a metaphysical problem in a world, the world programmers would have to be at approximately the same technological level and close to the same cognitive level as the simulated entities who might use magic. If the world simulation was written with a higher tech/intelligence level, there is no reason why the simulated entities should be able to access or understand it. Your Minecraft example doesn’t apply because it is a controller of the simulator (the player), not a simulated entity, that is able to use the cheat codes. So that gets us back to Arthur C. Clarke’s “any sufficiently advanced technology is indistinguishable from magic” and back to square one. [Answer] RAM, you need it to cast spells,it limits how much/how complex your spell can be, Mana could be something that tells magic exactly what to do, the instruction you think is engraved into Mana which in turn can communicate with magic and pass on instruction, when you run out your exhausted and can barely think Script kiddies get tired faster because they just copy a poorly optimized fireball spell that could cast 3 if properly done. [Answer] ## Frame Challenge The primary characteristic of mana is that it is a reservoir of resources that recovers in a trickle over time. In the entire world of computing, the only place you have reservoirs building up is when you're talking about a backlog of things that need to be done. Backlogs are a negative resource. It's something that you aren't doing right now because you're too busy doing other things. In computing, positive resources are static and assigned. Storage, processing power, and communications all behave that way. You don't store up MIPS and use them all at once when you need them. The concept of mana suggests that engineering is like bricklaying, but it's really more like architecture. This is the difference between process and design. Process is when you actually make something work, whereas design is where you figure out what processes will have the results that you want. [Answer] ## CPU time specifically for the physics engine ### Some background on how physics engines work Most physics engines in games have the concept of active versus sleeping physics object. When an object is actively moving, it is active. Every step all the forces are simulated, collisions are checked, the object moves, all computationally intensive stuff. On the other hand, sleeping objects are objects that have fallen on the ground. If all the forces on them stay equal we know they won't move so the physics engine does not need to simulate them until something interacts with them. In a game, you may notice that, for example, knocking over a large stack of physics objects can cause a large drop in frame rate as lots of sleeping physics objects have now become active. ### How magic could work In physics, lots of things need not be simulated unless observed. To save computational power, the exact position of an electron, for example, is not actually simulated unless needed. However, if one where to temporarily adjust the rules of physics, everything that was in a "stable" state now needs to be simulated till it reaches another stable state. During this time, computing the physics for the area suddenly becomes much more expensive, thus requires manna. In general, that means a given "spell" would be more expensive if: 1. It effects a larger area 2. It causes particles to move chaotically * For example, a low gravity spell would be more expensive than a high gravity spell since it would cause lots of floating dust 3. Things move in an unstable way for a longer time * For example, an explosion could keep draining manna as long as objects are flying around. On the other hand the high gravity spell could be kept going indefinitely since it doesn't really cost much to keep going after it starts. This could lead to interesting aspects for your story where a spell can keep draining manna for a long time after being cast, and stopping it would require more manna. If you run out of manna the universe may choose to simulate you incompletely to save on resources which isn't very healthy. [Answer] I want to say passion, but given that when you burnout you can't easily do your "magic", I'm thinking that mental energy is your mana. You'll need it at it's peak to work properly. Coffee can help, so can soda, but rest and relaxation, not thinking about code or doing anything mentally taxing, would be your best way of regenerating your "mana". Doesn't sound too exciting, but I couldn't think of anything else. ]
[Question] [ I shall present myself: I am Alfara Gal Strid, proud leader of a clan of Arat'nie - what you would simply call "winged humans". I come to you with a troublesome question. You see, for a long time we winged humans have faced war with your kind, effectively keeping your lot at bay using ranged weapons and dropping projectiles such as flechettes, arrows, bolts and darts using the ability to fly to our advantage. Now, though, since some recent diplomatic incident between the clans, we need to fight one another, brother against brother. Of course, this changes everything, since both parties are able to fly. What weapons would be best to fight in this situation? I'm especially concerned with melee weapons. As you might recall, our wings are connected to the body at out lower back, above the hipbone, and make us capable of vertical flight, along with some impressive aerial maneuvers. Our wingspan is quite wide - generally more than the length of our arms. We need weapons able to fend off our enemies, without risking to injure our wings as they flap. I'm concerned that spears, or even swords, might be dangerous for this very reason. Edit: As requested, I shall provide more details about my people, our body and our technology. Our wings are attached to our body at the hips, and we do have quite an impressive set of muscles at our lower back in order to operate them (You'll find a portrait of one of our youngsters at the end of this question). We can fly vertically, but our body can't - of course - just stay still; e.g. our torso leans forward if we are moving ahead, and so on. Wings can rise up to our shoulder level; this is necessary when needing good push or maneuvering. During normal flight they can be kept lower, but I don't think this could apply to the heat of combat. Still, yes: our flight isn't sustained by muscular force and wingspan alone, at least not always. In our world there are some particular air currents - called Aer - that we are able to ride. Our innate sense allows us to understand and surf those currents according to our need. Aer-less flight is still possible, but it's extremely vexing for our body. Frankly, I hope that dirt-dwelling humans will never learn to build kites and such items to exploit aer-currents; the very idea disgusts me. But I suppose it could happen. We are rather short compared to the average human (height going between 150 and 164 cm) and our bones are hollowed, making us more prone to suffer fractures. Regarding our technology, I fear that the world "clan" as led you astray. We are more civilized than you thought: we have knowledge of most metals and can effectively forge them into shape. Our weapon of choice is the [flechette](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwig85fu-tnaAhWHe8AKHb0_B74QFgg0MAE&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FFlechette&usg=AOvVaw34FUXfxGqQyVcsoEFDHt9a) that can be dropped on and fall into a straight line, or the light-crossbow when more precision is needed. Of course, we can't carry infinite ammo with us; the common strategy is to have squires carrying up additional supplies or setting ammo stations on horses on the ground, usually reasonably far from the struggle. This way warriors can drop and reload efficiently, but as I said, this wouldn't work well with another of our species. Our artisans give their best with tailoring. Being lightweight is paramount, as you can imagine; we mostly use cotton or silk, getting leather when a little more protection is necessary. We can craft more complex and sturdy types of armor - we don't lack the smiths to do that - but I fail to see how they could be used in flight; as someone noticed, our wings are mostly unprotected. I understand there may not be a best weapon. My concerns about spears and swords lie in the human use of those tools, which often requires big slashes that would be troublesome mid-air. Again, though, I may be wrong. I have been trained in traditional combat—that is, aim-and-drop—and that's the very reason I need informed opinions on new tactics. [![winged human](https://i.stack.imgur.com/XQCvb.png)](https://i.stack.imgur.com/XQCvb.png) Picture source: Gwendolyn from Atlus' Odin Sphere [Answer] Combat with rapidly moving humans on horseback is done by ranged weapons, so similar factors apply to your battles. Given the context in your question, it seems safe to assume firearms have not been invented in your world, so all weapons will be muscle powered. Throwing objects works well when fighting humans since gravity does most of the work, but when fighting aerial beings, the range of unassisted weapons like darts, javelins and so on will be very limited compared to the target, and the high degree of manoeuvrability also suggests you need some high velocity weapons to cover the distance before your target flies away. The answer is to adapt light crossbows. The fighters carry several light crossbow already cocked and with a quarrel in place. [![enter image description here](https://i.stack.imgur.com/sMuNw.jpg)](https://i.stack.imgur.com/sMuNw.jpg) Light crossbow. Note no stirrup for drawing, in case you need to try to reload it in flight in an emergency Upon encountering an enemy formation, they have several options: 1. "Zoom and boom". If they have the hight advantage, or are coming out of the sun, they can simply dive on the unsuspecting enemy, fire a crossbow then change to a freshly loaded one as they leave the area and begin their climb. A head on pass is similar to a "zoom and boom", except you are either level or possibly even climbing. The head on aspect ensures closing is rapid and leaves the enemy little time to react, while you shoot then dive away. This can break the enemy formation so follow up groups of your fighters can then engage more closely. [![enter image description here](https://i.stack.imgur.com/0zCBd.jpg)](https://i.stack.imgur.com/0zCBd.jpg) Zoom and Boom. The "red" fighter is diving on the "blue" fighter, and will discharge the crossbow at closest approach 2. "Turn and Burn". This is a manoeuvre in the horizontal aspect. If you are in a turning fight you can pull up during your turn to get inside his turn, then dive back down and discharge a crossbow bolt, switching weapons after discharging a bolt. [![enter image description here](https://i.stack.imgur.com/ZqagS.jpg)](https://i.stack.imgur.com/ZqagS.jpg) The sudden climb causes you to lose some energy, but puts you inside his turning radius, setting you up for a shot 3. Wingman attacks. You are probably used to wild melees diving on human targets. Fighting in the air requires discipline, much like our cavalry. Every senior figure should have a more junior fighter as a wingman, so when closing with a broken enemy formation you can pick a target while the wingman protects you. This also gives you time to fire and switch crossbows for a second shot if needed 4. If there are large enemy flocks, you can adapt a human cavalry tactic called the [Caracole](https://infogalactic.com/info/Caracole). Simply flying in a circular pattern and discharging crossbow bolts as you reach the closest approach, then switching to a new crossbow on the outbound leg of the circle will allow you to rapidly pepper the enemy with 2-3 crossbow bolts in quick succession (I doubt you would carry more than 3 light crossbows). Wingmen or other formations would provide top cover for the caracole. These are the very basic ideas of aerial combat. Refinements like flying at night, nape of the Earth flying and so on can be tested by your clan as you gain experience. Mastro Leonardo has been carefully studying the flight of birds (under the patronage of our Duke "Il Moro"), and has provided detailed observations on their flight. "Il Moro" has consulted with various philosophers to determine how these observations might apply to aerial contests such as you describe. [![enter image description here](https://i.stack.imgur.com/tab7e.png)](https://i.stack.imgur.com/tab7e.png) Mastro Leonardo would be interested in observing the activities of your clan [Answer] Ice skates. Or more specifically, bladed boots. In aerial combat it would allow you to slash at enemies below you without compromising your flight stance while leaving your hands open to carry some sort of buckler to defend against the attacks from others. With your arms free you could double the foot blades up with heavy darts to use as a thrown projectile. Your opponents have a big frame due to their wings, and you just need to damage the wings to make them plummet, so killing power isn't necessary. You can also drop the darts from overhead before engaging with the blades. Combat would involve a lot of drops and swoops as the two fighters attempt to get on top of and behind their opponent to slash at the unarmored wings (placing armor on the wings might make them too heavy to fly). Because the blades are on your legs your wings won't be easily reached by your opponent to retaliate without them doing an awkward flip or carrying a spear that might bump into their flapping wings and make them fall, and you can answer the spear by dropping a dart on their head. It might make landing more difficult, but not impossible. You'd just have to remove them after the battle is over similar to taking off your armor. [Answer] Long badminton racquets. [![badminton racquet](https://i.stack.imgur.com/pPmqR.jpg)](https://i.stack.imgur.com/pPmqR.jpg) * Lightweight, easy to carry. * Large surface area to maximize chance of successfully hitting aerial target. * Low air resistance, and so minimal resistance to swing. * Proven efficacy at whacking birdies. [Answer] Plummet your enemies to the death. Use bolas [![enter image description here](https://i.stack.imgur.com/Snbu8.jpg)](https://i.stack.imgur.com/Snbu8.jpg) * They are light, you can carry several of them in a bag. * They are ranged weapons, because you don't want your wings cut from a hand-to-hand combat. * You can make them with metal chains and they won't break, no matter what the other ones try. Barbed wire and spiked weights are possible variations. * Your bones are hollow and brittle: humans have used bolas to break the legs of quadrupeds. Even if you don't entangle the wings, you will break at least one. Laugh while you see them flying with just one wing. Remember than maiming your enemies can be better than killing them. * They are thrown by making them spin over the head. If you had wings like those mythological beings the humans call angels, it would be a problem. But you don't and you can become excellent throwers. [![enter image description here](https://i.stack.imgur.com/4q9Z0.png)](https://i.stack.imgur.com/4q9Z0.png) [Answer] I would like to point out that the weapons can’t be anything heavy (at all) and you would have to wear light Armour (Gambeson, or leather)not steel or iron to heavy to fly. Because being winged humans your bones would need to be hollow (making them brittle as well) and with air sacks inside your body keeping you afloat. * Long Claws or Bladed Gauntlets (long reach close melee, wont impact on your wings, good for stabbing and slashing) * Net Fighting (much like the gladiators, if your wings get tangled your gone or even a four man cell with a big net to trap whole units under it.) * Duel Blades (dive booming or glancing blow tactics to the wings would ether break the wings or cripple them, making it easier to finish off. in aerial combat you don't need to kill your opponent to take them out of the fight) * A Double Edged or Single Edged Guandao (the lighter version of this, they can weigh up to 70k. made out of wood and irons used by your most elite fighters to wield in combat. unlike the spear the guan-dao can use slicing motions better than the stabbing ones. they can dive down onto their enemy or slice up gutting them as they pass by, not to mentioning you can parry without an equal on the battle field) * Boomerangs (a weapon that is designed to return to the thrower it could also double as a blade if made out of iron with the handle in the middle) * All Forms of Missile Weapons (you seem to like close quarters fighting but bows and arrows are still you best friend, they open you battle tactics even more. Most if not all you troops should have a Missile Weapon of some sort, even a short crossbow would be fine. I have stated before you don't need to kill them to win, clip the wings and its over for them. [Answer] I think in the end your still going to end up with a weapons like a spear or trident and here is why: * Long Reach so you can hit enemies from further away without physically flying into them * Only the pointy end hurts people, the stick end won't damage your wings but could get in the way if they aren't carried properly * Can be thrown to hit enemies even further away * Carried parallel to your body so they wont interfere with wings * Don't need to swing and rely on generating momentum while in mid air. Can be thrust to take advantage of your speed in the direction of travel * Can store some extra spears along your back, either under or between your wings depending on how you have them designed Collisions in the air can be extremely deadly and air combat relies on speed and dexterity to hit the enemy where they can't hit you. In this case, shorter range and heavier weapons can't be used easily as they are hard to lift being mostly metal and have a long blade or require large swinging motions to utilize. Its pretty hard to cut through something then you only have your wings to stabilize yourself. Spears can be thrust and won't bog down your movement as much when you engage an enemy. It would be similar to jousting but in the air. You hit the enemy and keep moving on without pausing. [Answer] Several suggestions come to mind immediately, depending on what sorts of devilry your armourers can devise: * [Atlatl](https://www.youtube.com/watch?v=4TJW-qSOa9g) -- very effective!, but you need good aim. An atlatl is basically a light spear or javelin cast by using a throwing stick. The throwing stick (the atlatl itself) has at its distal end a small pointed peg (often of antler or bone) that fits into a depression in the butt of the javelin. This system is superior to merely throwing a javelin because a) the peg engages the very end of the javelin, allowing all casting force to be applied directly to the javelin without the negative effects of hand-on-javelin friction and the poorer transfer of energy and b), the length of the atlatl itself acts as a "third joint" for the thrower's arm, adding perhaps another eighteen to twenty-four inches of arm length and adding a fourth point of articulation. The effect here is increased power. Advantages for the Winged Humans in aerial combat: increased useful range. The record atlat cast is nearly 900ft, whereas the record javelin cast is almost 350ft. Both javelin & atlatl can be cast while aloft without concern for tangling the weapon in one's wings, though the distance advantage falls to the atlatl. * [Blunderbuss](https://www.youtube.com/watch?v=GCs2RIyeUwc) -- when fired from above, you don't need to aim! (as carefully) A blunderbuss is basically a smallish handheld cannon, a relatively close range melee weapon. Technologies required to make one: wood working (stock), bronze & brass casting (barrel and parts), black powder (for explosive propellant). A blunderbuss can be preloaded before flight, fired while in flight and reloaded whilst in the air. Recoil is minimal and should not adversely affect the warrior in flight. Ammunition does not require specialist tools or manufactory technology to make. A charge of powder, a load of just about any small, sharp rubbish (bits of metal, pebbles, lead shot, nails), and some wadding to hold the load in the barrel are all that's needed. Advantages: packs a punch! At ten to twenty yards, a blunderbuss sends a crippling to deadly cloud of shrapnel towards a foe. Large shot can kill, smaller shot can cripple. A blunderbuss is fired forward and thus will not become tangled in the wings. The heated gas exhaust can be frightening for a first time shooter!, as it looks like the gout of flame might set the wings on fire. But have no fear! The flash is short lived and will not reach as far as the wings! Disadvantages: weight. A strong warrior with powerful wings can wield one with ease. Anyone smaller or weaker should stay clear. Second life: when a warrior has used up all his ammunition, the blunderbuss works very well as a close quarters melee bludgeon! Just drop down upon a foe and give him a strong whack on the crown! Guaranteed to send even the hardest of heads plummeting dead to the ground! * [Molotov Cocktail](https://www.youtube.com/watch?v=lt9a7M2oRiA) -- simple, effective as no one likes to be set afire! A Molotov cocktail is a highly inflammable concoction of petrol and tar, mixed up and poured into a glass jar. Affixed to the jar, by tying it securely, is an oil soaked rag wick. A bombardier could carry a fair number of bombs, perhaps eight to twelve, packed and ready for use. When engaged in battle, the bombardier should position herself above the fray. Light the bomb's wick and throw it down upon a foeman's head or lower back. The trick is to hit something hard (like the head or equipment belt) which will cause the jar to break and its contents to ignite and splatter upon the foe's body. If his feathers are ignited, he will no longer be able to fly and will plummet to the earth. If any other part of him be ignited, the burning will drive him mad and he will dive, seeking for water in which to immerse himself. Advantages: Fire. Any weapon that burns will be a terrible thing to face for a foe on the wing. Disadvantages: Fire. Any weapon that burns is a great danger to the bombardier! A flaming arrow well aimed into her bomb pouch will spell her own doom. General advantages of these three systems over others on offer: * Bolas & slings; Meteor Hammers; Whips --- these weapons require the warrior to swing them in a very hazardous arc around the body in order to cast them. A warrior on the wing will much more likely foul his own wings than those of an enemy! Clearly, whoever suggested these weapons to our winged cousins is a ground crawler whose sole purpose is to cause you mischief! * Claws, Gauntlets, Blades, Bootblades, etc. --- all are fine additions to the armamentarium, but all suffer the same disadvantage: need to fight at close range. As you know from watching birds fighting while on the wing, most of the time spent in combat is spent in lining up an attack and disengaging from attack & recovering an advantageous position. This kind of combat is very tiring and not very effective! A better use of time in flight is to fight with ranged weapons that can kill or disable with a single hit. Just remember: while boot blades and guandaos look spiffy on your warriors, your enemies will already be smart enough to come at your warriors with ranged weapons first! [Answer] Something I haven't seen in any of the other questions yet and that I think might prove to be useful. manipulate and control the weather and environment as much as you can. Think smoke screens, toxic smoke jars and what not deployed under enemies. Mirrors are lightweight and can reflect the sunlight, negating the advantage one can have when attacking from above with the sun at their back. Is Aer physical or magical? can you stop/ block/ change the flows? If so, do it to your advantage. Make squads and teams and teach them how to fight like that. For large scale aerial combat like this chaos would soon erupt, it is far easier to organize combat as a small unit then hoping to keep order over two large armies smashing together. That being said, before combat starts, use volley fire of projectiles. Use weapons aimed at disabling flight. Fire arrows can burn feathers. Sticky thread and rope can bind wings, lace everything in toxins. Another thing that could work is having two soldiers carry sticks between them. Have thin, sharp threads go between the sticks and have them fly at the enemy. If they fail to spot the thread, they'll get cut up. This won't keep working of course. Use things like water balloons. But fill them with tar or sticky oil. Stuff that will make the wings not work anymore or work less efficient. [Answer] Human fighter pilots (including in helicopters and World War I vintage fighters) also use(d) "ranged and dropping weapons, as flechettes," "bolts and darts". You can continue to use your existing weapons. You will need to adjust your aim and range to account for your opponents' velocities and maneuverability. You will also need to study aerial dog-fighting techniques to learn how to get into position to make an attack using your weapons, and avoid having such attacks made against you. [Answer] Thanks for the extra info. The first thing to mention is training. You say that you're worried about cutting yourself or your friends accidentally with your weapon? Training with all weapons (swords or ranged weapons) is aimed at this first and foremost. Until you can keep yourself safe, you aren't ready to use your weapons for actual fighting. If you've ever handled practise swords, you'll realise very quickly how ludicrously easy it would be to slice your own leg! This is why schools of swordsmanship train particular positions and cuts - they aren't just putting your blade on the opponent, they're putting it where it can't easily cut you or be driven into you by a parry or blade beat. I imagine it would be possible to work out a similar system for your species. Your biggest problem though is not attack but defense. Humans can cover themselves reasonably well with their weapon, being a straight-up-and-down kind of body shape. You've got highly fragile wings, which are an easy target. Actual fighting manuals tend to favour attacking vulnerable extremities (arms or legs) with hand weapons, or aiming for centre mass with ranged weapons. For you, every attack will be aimed at wings, and it's basically impossible to defend them or avoid being got. You therefore have a basic problem that the first person to attack wins, but the victim can equally easily land a revenge blow before they fall. I simply can't see close quarters combat ever working for your species. Maybe carry a lightweight spear as a backup, but only in the way current soldiers carry a knife as a backup. The odds of actually using it on an open aerial battleground will be pretty damn low. Given this, I see your warfare being almost entirely ranged. And as with aerial combat in WWI with low-powered planes, the advantage goes to whoever has altitude. For weapons, you're looking at crossbows (repeating?) or perhaps short cavalry bows. For tactics, you're looking at Von Richthofen and all the dogfight doctrines that grew up in WWI. [Answer] Go ranged. The ol' slingshot and rocks would be a decent weapon, capable of injuring any part of the body from afar without having to burden the user with too much weight and entangling their own wings and limbs with longer or unwieldy weapons. If the opponent is lightly armored (can't be very heavy since the winged human would not even be able to fly", then you would need to just need to hit their wings to make them fall or "stagger" them. You can even use short bows if this makes more sense in your world, then you can have poisoned tipped arrows and such. For the occasional melee fighting, use a "tari" or what they call "chicken knives" used on illegal cockfights. Basically a sharp hooked blade attached at the back of the ankles to to slashing attacks and since its on the legs, you can also use your arms to punch, slash, stab or any use other martial art or weapon you can think of. Makes for an interesting fighting style. [Answer] Stage 1: When the avian wars began we used whatever weapons came to hand. This meant heavy flechettes originally forged to combat armored ground-based troops. They were devastating under the right circumstances $-$ a direct hit would quickly take your enemy out of the sky. There were two drawbacks. 1. Those things were heavy. Against ground troops we used to stash ammunition in high positions unreachable by foot before the battle. That meant no soldier had to carry more than a few shots at a time. This strategy fails against aerial foes who can easily raid our stashes. So it became a toss up between ammo and agility. Carry more shots and you have more shots; the advantage is obvious. Carry fewer shots and you can fly faster, dodge better, and better avoid enemy shots. 2. We were vulnerable. Against ground troops we used to attack from a few hundred feet up. While human longbows were vastly more powerful than our missiles the extra height made us untargetable as long as we kept moving. This no longer applies when the enemy can fly up to meet you. Stage 2: We started forging weapons and armor specifically to target aerial foes. 1. Lighter flechettes. Nowhere near heavy enough to damage a ground-based foe. Or even harm an aerial foe if launched uphill. But light enough to carry for a protracted battle. During the skirmishes in Stage 1 we noticed most of our troops' injuries were on the wings rather than the head and body. Understandable since the wings present the largest surface area. With these lighter flechettes the wings become the main target. Even a fall from 20ish feet can break bones. In any case a damaged wing takes a soldier out of the fight. 2. Armor. The obvious countermeasure against light flechettes is to tuck in the wings around your lower back. This leads to freefall so you need a height advantage first. Battles became about getting out of enemy range, taking the high ground, moving above the enemy, tucking in the wings and shooting from above. For extra protection we made light shields and collars to hold ahead of us and protect the narrow profile offered while diving. Again these were flimsy against ground-based weaponry. But they were angled and strong enough to deflect a light flechette thrown uphill. Once or twice we experimented with what the humans called melee weapons. It was a disaster. With two swords/spears/tridents and four wings whirling about mid-air every soldier was as much a danger to themself as the enemy. A few oddballs took advantage of this fact. "Since melee weapons are obviously such a bad idea," they said, "no one in their right mind will use them. So if we engage the enemy hand-to-hand they'll have no way to defend themselves". They were half right but, without special training, these commandoes still likely to break their wings against the enemy's wings in the bind. Plus we had no history of forging large weapons so, all in all, it was a specialised and expensive tactic that didn't see much use. Battles were decided by whoever gets the high ground first. They attack from above and force the enemy to ground level, where they have no choice but to land and tuck in their wings and use their shields for protection. This is moderately effective since our weapons were so light. But since the enemy is not going anywhere, we take this opportunity to gather heavier ammo (rocks) to drop on them. They quickly surrender. Stage 3: After being forced to the ground too many times our enemy realize if they give up on flying and wear proper land-based armor they are invulnerable against our piddly anti-air weapons. After devastating us in the first few skirmishes we start mixing heavier flechettes back into our squads. In response they reincorporate light flechettes among their ground based troops to defeat our heavy flechettes. A game of rock-paper scissors develops. Ground troops > light flechettes > heavy flechettes > ground troops Now every army has some mix of the three that move independently to counter each other. Warfare becomes complex. Weapons stashes return since enemy ground-based troops cannot use our stashes mid-battle. But the stashes must be hidden so they are not raided between battles. We can also use blocks of ground troops as mobile stashes if given the time to prepare. Armor is also stashed since our ground troops have terrible mobility. Since we live on cliff sides, deep forests and other rugged areas that necessitate wings, a landlocked enemy army can safely be ignored. If we want to move our ground troops they need to disarm, stash their armor for later use, fly to the new location, and re-arm from a nearby stash. Finding and raiding enemy stashes between battles becomes vital. We experiment with anti-ground ground troops: Non-flying combatants armed with melee weapons. There is some success but our light bones mean we can't put as much force behind our weapons as humans can. Spears and polearms are popular since the metal components are smaller and easier to forge. Also longer two-handed weapons don't need as quick of a swing to do good damage. [Answer] You want a weapon that is A) relatively light weight, B) is not too difficult to aim while moving, C) works at medium range, and (very importantly) D) works against mobile targets. For all these reasons, I recommend bolas! Ideally, you will have two weights, connected by a thin, strong wire, or rope, with padding near the weights, allowing you to spin or grip them comfortably. Bolas have an advantage over arrows, sling-stones, and similar projectiles because their in-flight cross section is considerably larger, so they're much more likely to hit your target when both of you are actively maneuvering. This is a similar reason to why chain-shot or chain-and-ball shot was used against rigging and masts on ships. Bolas were used in combat by the Inca and the Maya, and were used in hunting against large birds —which you more or less are! [Answer] The two most important aspects will be: 1. Reach: Being able to hit your opponent at longer range is always huge advantage. That's why most soldiers used spears, pikes, lances and other polearms as primary weapons. Swords were almost always secondary weapons for use if the primary weapon was lost or the fight became too close for the long polearm. Of course, ranged weapons have even longer range, but lower accuracy and limited ammunition. 2. Weight: The effort required for sustaining flight, and for all manoeuvres, is directly proportional to your weight. Also, swinging anything heavy around would get you out of balance quickly as you don't have any solid support. So what weapons come in consideration: * Bows: I am going to suggest bows rather than crossbows mentioned in the other answers due to their lower weight. Crossbows were mainly preferred as they required less training, but in trained hands a recurve composite bow is every bit as deadly. * Bolas: Shorter range than bows, but more likely to hit both due to their larger size and because you are targeting the wings with them—the wings are not all that vulnerable to arrows since most of their area is just feathers and piercing through them won't cause pain and very little damage. On the other hand bola will interfere with moving the wings, which is crippling. * Blowguns, for the low weight of their ammo, especially if you dare to dip it in a poison. * Lasso: Similar to the bolas. You'd probably have to let go of it if you score a hit and let it plummet to the ground with the opponent, but at least you'd get to keep it if you miss. The price is the limited range. * Lance: A long, rather thin (for low weight), spear would be most practical melee weapon. Attack would almost always involve flying with it outstretched forward and using your own momentum to impale the opponent from behind or other angle except head on (which would usually end in mutual kill) in a style rather similar to cavalry charge except with no shield you'd rely more on manoeuvring advantage. It should be long enough to reach beyond your wingtips so you can use it to deflect opponent's spears and also bolas and lassos. * Halberd: Adding a blade to the tip might be useful because as the wings are not that vulnerable to piercing attacks they are much more vulnerable to slashing ones (as that has higher chance of hitting the ‘arm’). However, the blade would make it heavier and swinging it around would make you turn the other way, which would be hard to compensate without the luxury of fixed support one has on the ground. Might be a thing for the strongest elite fighters. * Spear: A shorter spear as side-arm for ranged fighters so they don't feel completely helpless when they are out of ammunition. Not much actual value though. In either case: * Shields are not practical as they are heavy, cause a lot of drag and can't protect the outer wings anyway. So you'd need to rely on manoeuvring for defense. * Since you are very vulnerable from behind, you should be flying with wingmen to cover your back. Flights of 3 or 4 may be an option. * You need certain speed to fly efficiently (there is a speed with minimum drag; flying slower produces more drag and thus takes more effort to sustain) and manoeuvre well (at lower speed your wings can't generate as much lift and you need that for accelerating sideways to turn). You are rather large for flying creatures, so the practical speed would be quite high. Say about at least 30 knots (55 km/h). That's pretty fast. Faster than horses. At that speed, there can't be much parrying. The fight will be series of charges and evasive manoeuvres. However flight will be usually quite smooth (subject to weather), so aiming the bows is not as hard as from horseback. * Most of the time you'll have critical shortage of cover. However, sometimes clouds will be usable and surprise take-offs from under cover may be an option. But don't underestimate the dangers of flying through clouds—while being able to feel the wind around your wings does give you some advantage over aircraft pilots, you are far from immune from spatial disorientation. Also, many encounters will be fights for some resource and that will obviously be on the ground, whether it is a city, fortress, mine, factory, etc.: * You'll have some ground-based artillery, shooting from larger ballistas. Instead of big bolts, they are likely to shoot nets or some variants of bolas. * You still get to do bombardment, with various things. Flechettes may be effective against personnel, but to take out the defense weapons, fire will most likely come in handy. (Update) Oh, and one more thing: an otherwise non-fatal injury might cause you to fatally crash to the ground. Therefore for all the weight savings a parachute might actually be well worth it! [Answer] Pole arms The whole reason your people prefer missile weapons is because they want to keep hostile people far from their wings. The same desire would apply to melee weapons, so they'd pick a weapon that has reach that is longer than their wing span. They'd also want the weapon to be light weight compared to its length and easy to keep away from their own wings. This suggests long rigid pole made from wood or a hollow metal tube. They'd also want the weapon to be capable of strafing attacks converting their flying speed to increased damage from slashes. And obviously it should be effective against wings so swinging cuts should be relatively easy and effective to do. These suggest a pole arm with a long light weight, and thus probably springy, pole and a relatively light cutting blade at the end. It would be used in wide swinging cuts and slashes boosted by rapid movement. I doubt such weapon actually exists as humans generally fail to understand the importance of not accidentally damaging their wings. Stupid humans. EDIT: It occurred to me while reading other answers that I failed to fully explain my rationale. Specifically the physics of it. While flying you basically have no leverage to power either swings or thrusts. A thrusting weapon relying on sharpness such as a dagger or fencing weapon might work but those are not really (apart from early rapiers) practical as primary military weapons. And for a flier any weapon that requires you to stop relative to the enemy due to either close range or need to avoid direct collision is a bad idea. These factors disqualify all thrusting weapons and any swinging weapon that relies on the momentum of the swing or is short enough to require stopping to protect your wings. Thus basically all melee weapons used by humans have been disqualified. The weapon must be something that uses the one special quality, flight, that humans do not have. Basically instead of generating force by swinging the weapon, which as mentioned does not work, the fliers will generate force by flying rapidly. The weapon will accelerate with them thus gaining energy and momentum. Then the flier flies at the target, avoids the collision themselves but lets the weapon collide with the full speed of their flight. The weapon does not swing, the flier turns. The description of the weapon that follows from this is as mentioned in my answer before. But one thing I cut from the answer before but am adding now that I am making this excessively long anyway is chain weapons. I also neglected to properly explain why the pole should be springy. Basically you do not want the weapon to transfer the impact back to its wielder. A springy weapon with proper technique gets close enough. A chain weapon is even better. The two alternatives are a chain hanging below the flier and then flying over the target or a light weight chain in a relatively long pole. Either keeps the chain from messing your wings while you use it to hit the target. [Answer] The problem with ranged weapons is carrying enough ammunition to stay in a fight for any length of time. On the ground or on horseback, its easy enough to resupply yourself. But in the air, you could really only carry a few shots at most. So your battles may begin with a skirmish-like feeling where we lob things at each other, testing our resolve to actually fight each other. But once we run out, I think we will engage in a more birdlike fight sequence. There's basically two ways birds fight to kill: 1. [Lock talons and freefall.](http://www.baltimoresun.com/features/bs-ae-tangled-bald-eagles-20150127-story.html) This is like a game of chicken, you try to knock-out, scratch, whatever your opponent as much as possible while you both fall and try to disengage before you hit the ground in a way that your oppnent can't disengage in time. 2. [Dive on your opponent and punch.](https://web.stanford.edu/group/stanfordbirds/text/essays/Raptor_Hunting.html) Falcons' use this to great effect. They will gain altitude above their victim, then enter a steep dive. They will then strike their prey with their claws as they fly by at high speed. So I would imagine a human 'bird' would carry a weapon like the [Patu](https://en.wikipedia.org/wiki/Patu). Short, heavy, somewhat-sharp. It would be excellent for extended battles, being that you don't throw it away at each use, it's highly maneuverable and packs quite a punch. It would be ideal for both types of attacks I outlined above. [Answer] I'd suggest a ranged weapon not mentioned here, but quite widespread in this lowly human world. It can also be fanservice-y enough for you people having wings at their hips with no additional scapulae or carina. Because come on, girls with guns! # Firearms You people are advanced enough for the flight, diplomacy, flechettes, and zettai ryoiki. You should have gunpowder. Smokeless gunpowder. Many will tell me that recoil and ammo limitations make it impossible. Below, I prove them wrong. The recoil, weight of the automatic reloading system, weight of ammo – they all depend on calibre. While other mechanical flies preferred increasing munition calibres during the dogfight era, the reason for this was how much easier is to shatter a lowly human flying mechanism (also known as an airplane) with larger projectiles. Humans have successfully developed and almost deployed warfare firearms with calibre [less than 5 mm](https://en.wikipedia.org/wiki/4.85%C3%9749mm). There were automatic weapons with fire range around 1000 metres. You wouldn't need this much, at least initially. This allows to reduce the amount of gunpowder, and hence the weight and recoil even more. So, take calibre 2-3 mm, shorter barrels, a lot of rounds – this would be my idea for your armament. To counter small calibre I'd suggest elongated or arrow-formed projectiles. First idea would be pistols, or, better said, sub-machine guns. [Uzi](https://en.wikipedia.org/wiki/Uzi) might be a good source of inspiration. You'd need a rechambered version for your freshly-designed ammunition and larger magazines. In the later onset, the fire distance would increase steadily. So, as a future weapon design I'd outline known [Gast gun designs](https://en.wikipedia.org/wiki/Gryazev-Shipunov_GSh-23), notorious for their airborne use by some humans. You'd need to scale them down, of course. But this scheme has apparently some benefits to the Gatling scheme in regard of the gun weight. Notice, that you need to hit your target, hence you need a lot of ammunition. As aerial combat making precise aiming hard. But your target is barely armoured and is a human, albeit a winged human. A single hit would suffice, as it mostly will render a combatant incapable. Even worse, they might as well loose the concentration needed for the flight and fall down. [Answer] The weapon that in my opinion would be most effective is the katar sword.[![enter image description here](https://i.stack.imgur.com/BuulW.jpg)](https://i.stack.imgur.com/BuulW.jpg) It would be a weapon designed to act as an extension of the hand. It can be used for slashing, but it is primarily a stabbing weapon that is designed to penetrate gaps in armor, it is short enough so as not to interfere with the wings and can take momentum from divebombing and such. [Answer] Honestly with wings that low (around the hips, from the picture you provided), you could use anything. Also, it looks like defending from below is actually easier, since you wings are beating around your legs. Keep any weapon above your hips and you're good. I'd probably recommend daggers, both to wield in melee, and also to throw. You're flying, so you can turn 180º both vertically and horizontally very quickly, so you don't want a heavy weapon that would take time to swing around and follow your body. Daggers are simple, can be coated in poison, you can carry a lot of them. To make things more custom/interesting, I'd recommend tying a string and feather to the handle, to make it fly point-first when thrown. [Answer] So you want to fend off flying enemies, without using blades? Sounds like you want a big cudgel. Maybe with a few studs and a hook for grappling. Here, try one of these: [![enter image description here](https://i.stack.imgur.com/hAujZ.jpg)](https://i.stack.imgur.com/hAujZ.jpg) [Answer] Nets are deadly in air combat. Even more so if used with a crossbow like launch mechanism for moderate reach. [![enter image description here](https://i.stack.imgur.com/uzaoa.jpg)](https://i.stack.imgur.com/uzaoa.jpg) You'll also need some long sticks (e.g. shortspears) to defend from the nets. [Answer] I'm reminded of the aerial combat described in the book Oathbringer by Brandon Sanderson. The flying characters use very long spears. [![enter image description here](https://i.stack.imgur.com/tojBB.png)](https://i.stack.imgur.com/tojBB.png) [Answer] A bolas may be efficient, as it may be possible to throw in turn with wing-strokes. The distance of a longer wingspan may allow more torque than a 'ground-dwelling' biped, as well as the ability to swing the weapon in rhythm with timely wing flaps. Or how about a penny? Dropped from great heights (especially with extra force from a flap) could be effective, no? [Answer] Create aerodynamic kites with long wings, like this: [![enter image description here](https://i.stack.imgur.com/h81T9.jpg)](https://i.stack.imgur.com/h81T9.jpg) The only difference would be to put large spikes on the tip of the nose, that look somewhat like this: [![enter image description here](https://i.stack.imgur.com/KHxuy.png)](https://i.stack.imgur.com/KHxuy.png) On a day where the Aer is in the direction of your enemies, release these gliders. Upon hitting your enemy, the steel will slide along the flint spike as it plunges into their flesh, generating sparks and setting the rest of the spike on fire. For a bonus, make the entire kite out of wood to prevent sabotage (unmanned kite, for clarification). [Answer] Is the goal to kill each other, or is it more like a knight fight in the middle ages where yeilding (and thus shaming the enemy) was just as acceptable? ]
[Question] [ I'm just an average person. I'm not a millionaire with thousands of dollars to spare. I don't have any kind of special power. I'm not currently affiliated with anyone working on anything grand. I'm just a 20 years old college student trying to get through life. However, for one reason or another, I'm expecting myself in the future to travel back to the past (my future, his past) for whatever reason. It might be to warn myself of a future disaster or something grand, so I can't simply get others involved. I'm also a huge skeptic so since time-travel is real, why wouldn't there be a possibility that there are mind-readers? How can I prepare myself to verify that someone is myself from the future? --- Let's call my future time-traveler self "FTS" and my present average self "PAS". My background is in Information Security, so my first thoughts come to Multi-Factor Authentication (MFA). ## Something I know ### Past Events The easiest things to have FTS talk about are events in the past, especially things so embarrassing that I'd swear to take them with me to the grave. However, human memory is finicky, so memories of past events are easily warped. ### Passphrase to be remembered I can try to memorize a passphrase and commit it to memory. This passphrase should be hard to forget, so the problem of bad memory should kinda be solved. However, mind-reading is a possibility, so someone can read the passphrase from my mind as I ask them about it. ### Future Events I can get FTS to state a future event. Something like the lottery would be too random and is easily changed thanks to the Butterfly Effect. Big natural occurrences like earthquakes would take too much time to verify, since we'd have to wait for them to happen. Man-made events such as crimes have insufficient credibility, since FTS could just cause them after stating them, or stage the event to happen shortly after his statement on the event. [Solar Weather](https://worldbuilding.stackexchange.com/a/12374/70360) seems like something an average person would have a hard time verifying. ## Something I have What do I have now that can be reliably stored for decades? I may get a big hard drive, put a lot of random data on it, and put it in a secure vault. However, having a single device would be too unreliable, and trying to put multiple drives in multiple different vaults maintained by reliable third parties would be too expensive for the average person. Also, whoever I entrust the drives to would be able to impersonate FTS, and I can't trust them. ## Something I am User fingerprints. This is cheap, fast, and simple. However, from what I've read, fingerprints are not as unique as Hollywood makes it out to be, and I can't be sure FTS will have the same number of fingers as PAS. Just get a DNA test. This is currently my simplest idea. I'm no biology expert, but there probably isn't anyone that isn't me who would get the same results as me, right? But then again, as far as I know, DNA kinda changes over time, so it may not be as reliable as I'd hope. Additionally, FTS could have been exposed to some radiation that changed his DNA. --- This is not a duplicate of [15448](https://worldbuilding.stackexchange.com/questions/15448/how-to-convince-your-past-self-that-you-are-from-the-future-with-limited-memorie) since I'm just an average person without super powers. This is not a duplicate of [12348](https://worldbuilding.stackexchange.com/questions/12348/how-do-you-prove-youre-from-the-future) because I'm relying on myself alone to prove the time-travel. [Answer] # Predicting Future Passphrases Dialogue: You: How do I know that you're me? Future Self: I've written down a passphrase on this paper. You: I don't have a passphrase. Future Self (hands the paper over): You don't have one yet. Put this paper in your pocket, then take a minute and think of the strangest passphrase you can. Then take it out and read the paper. Be sure to remember the passphrase for the next 40 years, or this won't work. You: What if you can read my mind? Future Self: It doesn't matter because I can't change my answer, it's already written down in your pocket. You: Oh yeah! (pause) OK, I just made up the passphrase "Flibbertigibbet walks upside down". Let's see if it matches. (takes out paper) ... Wow, I've really got to remember to take better care of myself! Future Self: Hey! [Answer] We need a test that lets me (PAS): * prove the person in front of me is FTS * prove the person in front of me did not read my mind * prove the person in front of me did not cheat through additional time travel * not sensitive to butterfly effect I don't think it's possible. Any test that relies on a mental attribute, such as remembering something or solving a puzzle the right way, can be cheated through additional time travel. As previously mentioned, (fake)FTS stops in 2021 and tortures the answer out of me, then comes to 2020 and delivers the answer to me. This even works with the 'put this in your pocket then write down your own passphrase and see that I got it right' method proposed in another answer. Mind reading is a substitute for torture if you wish (and if time travel is real and this isn't just a present-day faker). Any test that relies on a physical attribute such as scars or implants or even fingerprints can be cheated even more easily. With all of time to play with, there is every likelihood that (fake)FTS can find a doctor to change him physically to match the test. Tests that do not require either physical or mental attributes will not prove any continuity between PAS and FTS. In the world of cryptography, the problem of proving who I am is solved by use of public key infrastructure, and it requires a trusted authority. From OP's question, he doesn't trust anyone, and when time travel is involved any data test can be cheated with additional time travel, just like the mental attributes. I conclude that it is impossible to convince a sufficiently paranoid PAS. [Answer] Specific future knowledge Future you is from the future. You agree (with yourself) that if you ever need to travel back you should do so armed with some future knowledge from the day after your arrival date. This knowledge should be publicly obtainable, well recorded, hard to forge and relatively continuous. Temperature records, obituaries or newspaper headlines should do nicely. In today’s global society you can get information from anywhere in the world, so you’re spoilt for choice. Furthermore you agree on precisely what piece(s) of information your shibboleth will be and (should you ever need to change it) record what the required info is for any given day. When future you decides to travel back they can simply look up (and pick up, if they’ve been storing old newspapers) the shibboleth for the day after their arrival date, meet you and Present their credentials. You then wait a day and verify the information. If someone is a mind reader they will know where the information should come from but not what it is. If they’re not a mind reader but are from the future they won’t know what information to present to you when they return. If they are you they will know both what key you expect to be given and the value of the key from the future. This falls over if your mind readers can also travel back in time, but in that case there is no way to do this since the attacker can always get the information required to break your security from future-you... [Answer] Go for a vacation to the secluded place, alone. Make a tattoo on your chin. Don't use a mirror, so that even you don't know how exactly it looks like (that takes care of mindreaders). Wear a beard for the rest of your life. When FTS arrives, shave and compare. [Answer] Inception In inception they have a similar problem. How can you distinguish something as real or a dream if people can recreate any aspect? By having a totem. A totem is something you have with some properties only you know. A chess piece with a certain weight distribution, toppling over at a certain time is one example they give. But it can be anything. From a secret compartment with a key to an inscription felt somewhere on the totem. If only they know this, it'll be next to impossible to recreate this in a dream for someone else. So all that is required is 1. Having the totem. 2. Knowing something special about the totem. 3. Protecting the totem at all costs, so only you have this knowledge. This way you can be reasonably certain that the person is you. But as with all ID, you're not relying on just one. You're already referencing n factor authentication. So why not add some? DNA however is difficult. You'll need the equipment yourself, so no one can fake or tamper with it, and have the know how to work it. Not an easy task for an average joe. Even then they might have gotten DNA from you in the past, so they might still be able to fake things. And if you go deep enough youll see that environmental genetics will change the gene expression as well, making things not identical. But we probably can't verify DNA of me or my identical twin because of this. So they could possibly clone you and just use that for the required DNA, or even just send a brainwashed clone depending on the technology. Still, for 2 or more factor identification it's not bad. Data can be reliable, more or less. But it requires storage in crystalline structures. Again, not easy to come by. So I would say a totem first and try to verify it with one of the other possibly more complex or less reliable methods as extra security. Even just pretending that's the official way would be great, and only your future self would know about the totem. This way, you might not even need to protect a totem, so no attention is ever brought to it. [Answer] Biometrics. More than one kind. DNA would match to your lab grown, artificially aged clone as well as to you! But there are other biometric identifiers that are generally thought to be stable (not changing with age) and epigenetic (even your twin would have different ones). Use multiple types to increase certainty. Fingerprints: You've mentioned that fingerprints change over time, which is true, but as long as they are not too worn down they are still recognizably the same. Also you mentioned that your future self may not have the same number of fingers as your current self, which is also true, but it isn't a problem as long as your future self still has some fingers left. More fingers is better, but if you could match 8 out of 10 and the other two are missing then you're doing very, very good. You also have some things going for you, in that you can take your time to collect really high quality prints for both sides of the comparison. With crime scene matches, etc., they are often working with only partial or poor quality prints. This is also difficult to tamper with, you can examine your future self's hands to make sure there's nothing funny with them and provide your own ink, paper, and magnifying glass. Then do your own comparison. Facial recognition. Not the fast-but-bad kind like phone unlock, but shell out for the really good kind that gives you a percentage of match. Use it in conjunction with other methods. Iris recognition, palm vein recognition: Might be a little harder to get your hands on the hardware for this, but I think it is at least commercially available. This would probably be cutting edge for current consumer technology. Biometric recognition of the future: Voice (better than today's which kind of sucks)? Gait pattern? One potential problem from the comments--someone could (theoretically) grow a clone, kill your actual future self, and then do hand/arm transplants and eye transplants onto the clone. If they can grow a clone, we will accept that they can also do transplants so cleanly that it is impossible to tell. But I do still like this as part of a multi-factor authentication. [Answer] ## Whatever you do, it won't matter Your future self will remember what it is that proved your identity to yourself. You'll just do that. I mean, if my future self came and visited me. I think it would be an event I would remember for a long time, even as long as it takes me to find a way to travel back in time. Thus, if my future self is able to convince me that I'm from the future, then I already know what to do, and there's nothing I can do to prepare for meeting me. [Answer] I thought about it and my own personal solution is something like this: Several pieces of totally random emotions, memories, and dreams that I never disclosed to anyone or written down. The totally random part insures 2 things. Very unlikely that they another person will use to fact check. Very unlikely to be on top of my mind. The combination above is way more personal and better to verify who that person is. My high school score or body scars or porn history or medical history or other such things can be learned. But who on earth would remember a dream in which you where trapped on a rooftop surrounded by zombies while the moon was a large spaghetti ball? However, it's possible, depending on the setting, that the introduction of mind reading can complicate--and possibly even annul this solution [Answer] # Self-multilate Your future self will arrive whole. When they do, cut a finger off of your own hand. That finger should then disappear from future you, maybe to be replaced with a prosthetic one. Here is a graphical example: [![Past Leo meets future Leo. Future Leo chops past Leo's arm off. For Science.](https://i.stack.imgur.com/uPjWV.png)](https://i.stack.imgur.com/uPjWV.png) [![Future Leo loses his arm, gets excited to try on the other arm.](https://i.stack.imgur.com/tl1Ii.png)](https://i.stack.imgur.com/tl1Ii.png) [![Science is done, but the damage is already done.](https://i.stack.imgur.com/mk0TE.png)](https://i.stack.imgur.com/mk0TE.png) Source for the comics above: <https://www.vgcats.com/comics/?strip_id=271> [Answer] The mind reading makes this really hard, but I think I have a fun solution never tried before. Untested biomarkers. When future you shows up, the two of you go to a perfume store. You each separately sample 50 scents, writing down for each one how much you like it on a scale of 1 to 10. Then, compare your answers. They should be within 90% the same or so (with some variation caused by future experience, like a hated future ex-girlfriend who wore a certain scent). Oh, a couple edits for four dimensional safety. The exact store used should be picked by a random number generator, which because of chaos theory would be different each time someone went back in time, so they can't try this twice after screwing up the first time with their new answers from the past. And during the test, future person has to write down answers first to prevent simultaneous mind reading. And of course you have to burn your answer sheets after reading, and only past you gets to read them (making all effort not to remember answers, as a double firewall). [Answer] Step 1: Get a dollar bill. Step 2: Tear the dollar bill in half (keep the smaller half) Step 3: Always keep the torn piece of dollar bill with you. If anyone presents you with an identical piece of torn bill (ignoring reasonable minor wear), they almost certainly travelled from the future (or a parallel dimension?). Copying the randomness of a tear is pretty nearly impossible. Dollars are durable and fairly water-resistant, so it's unlikely to suffer more than minor wear if you're not excessively careless. And having a torn piece of a dollar is relatively inconspicuous, so people are unlikely to guess that this is something special and try to hijack it. Bonus points if you rarely think about it, making it less likely that a mind-reader can anticipate the test and think of a workaround. But how do you know it's actually you? Well, you can never really be certain of anything, can you, Monsieur Descartes? [Answer] Spend time with yourself Assuming you do not have a hard time requirement to accept FTS as your true FTS, simply spend a good chunk of time together. Play all the multiplayer video games you both love, prepare some dinner, agree on a movie, etc. Date yourself as they say! Depending on the age difference of PTS and FTS there really shouldn't be that drastic of personality differences. Knowing yourself is also something that a mind-reader cannot overcome that easily because it isn't about a right answer it is about all the unspoken things that make yourself, yourself. The mind-reader might see that you have started to notice he isn't gripping a fork the way you do but by then it might be too late. Copying someone 100% in everyday behavior is near impossible. [Answer] Your question dismisses two solutions incorrectly. ### Fingerprints Fingerprints are fixed before you are born, and never change. <https://www.sciencefocus.com/the-human-body/can-fingerprints-change-during-a-lifetime/> It is possible to have fingerprints surgically altered, but minor changes will grow back. If you wait around a month, you can verify that this is correct. People have had skin grafts to remove fingerprints, but of course this won't help them pretend to be you. ### DNA Your basic DNA sequence doesn't change, ever. This will remain constant. Testing for it is somewhat hard at the moment, of course. If you're preparing for this to happen though, it's possible that you might have set up for a career in a lab testing forensic samples for the police, and you can put your samples through the same equipment when this happens. What does change is methylation, which affects how DNA produces proteins. The "code" itself does not though. [https://genetics.thetech.org/original\_news/news91#:~:text=A%20study%20just%20out%20shows,get%20older%2C%20our%20DNA%20changes.&text=Researchers%20in%20Iceland%20and%20the,in%20something%20called%20DNA%20methylation](https://genetics.thetech.org/original_news/news91#:%7E:text=A%20study%20just%20out%20shows,get%20older%2C%20our%20DNA%20changes.&text=Researchers%20in%20Iceland%20and%20the,in%20something%20called%20DNA%20methylation). [Answer] This depends way too much on your specific model of time travel for a comprehensive answer. More specifically: How sensitive to change is it? Can your future self change the past by his actions or not and what kind of ripple effects will there be? Because you have two different problems here and most of the answers address only one or the other. You want to prove 1. future you is really you 2. future you really is from the future Using a past event, something like a very personal memory, or DNA or whatever, only proves that you is you. If you are sceptical, that doesn't mean you are a time traveller - multiple worlds and alternative dimensions are more likely than functioning time travel. You need a very personal event that is still in your future to identify both parts. Also one that cannot easily be manipulated. It also must be in the very near future, you don't want to wait for a year. Randomness is the big equalizer in this world. Carry a d20 with you (a 20-sided die, you can buy it in gaming shops). Your identification is rolling it five times, with FTS writing down the sequence right before you roll. Since it's a random event, it isn't something that would be in your mind and a mind-reader will have no advantage. It is reasonably secure against guessing (1:3.2 mio - roll more time if that's not enough for you). It is also within the realm of digits that you can commit to memory so it doesn't have to be written down (for the PAS-to-FTS transition period). --- This does not protect against an adversary who is both a mind-reader and a time-traveller. I doubt that anything can protect against someone with those powers, as they could also likely manipulate DNA lab test reports and such like. [Answer] Do you trust yourself? Specifically, do you trust yourself to keep something safe for years and possibly decades? If so, here is a method to try: > > 1) Ask FTS, "Have you brought it?". If they ask "Brought what?" then it isn't you. If they answer "Yes", continue. > > 2) Take 6 pieces of paper and a scribble on each with your eyes closed and out of sight of FTS until you are satisfied with their level of uniqueness. > > 3) Fold each piece of paper in half so that neither of you can see the resulting images. > > 4) Label the back of each piece of paper 1-6. > > 5) Ask FTS to produce the proof. > > 6) Roll a 6-sided die. > > 7) If the scribble corresponding to the rolled die matches EXACTLY FTS's proof, discuss important matters of your future and their past. > > > > [Answer] Safety Deposit Box with a secret code: I'm not sure you can have a fool-proof method of preparing for a contingency that may not happen with theoretical enemies of completely unknown capabilities. Don't overthink, keep it simple. If it gets too complicated, even YOU might screw it up. And if the (fill in the blank) enemies are that savvy, you probably can't stop them as they make you remember that your precautions were really something else. You specifically are concerned that a future person may be able to convince you they are you (doppelganger) and that they can read your mind (telepathic). If they can control your thoughts or memories, you're screwed. What happens if you send a son or daughter in your stead? Anyone can claim to be such, or could even be so (kids can betray you).Given sufficient time and resources, you can't stop them - they can just travel back to before you came up with your scheme, or even travel to when you were making the decision and read your mind then, exactly knowing your scheme. If they can't come up with a solution to satisfy you, then they can come up with a hypothetical (potentially with years of planning) to convince you why they can't fulfill your conditions. My thought is to write down a long string of numbers, then get a safety deposit box and deposit the paper in the box. Don't remember the numbers, and don't tell anyone about the numbers. A future self will know you have the numbers, and can either memorize them or bring them along to show you. A doppleganger fake self will arrive with mind-reading power and learn you have a safety deposit box with numbers, but won't know them, because YOU don't know them. Only you go into the vault to check the numbers, and if the first few digits don't match, stop reading and get paranoid. If you can get a bank to agree to only admit you under certain preconditions (the first Tuesday of a leap-year) You would need to be at the bank every leap-year Tuesday to watch out and prevent Doppelganger from obtaining the info. Your future self would know to only arrive on a first Tuesday of a leap-year. In a time-travel future, hopefully eventually the banks then have security against the threats they face then, and the doppelganger can't just travel forward in time to steal the numbers. You can't prepare for every possible unknown technological contingency, and if you are conceding a hypothetical enemy that can read minds and physically convince you they are you, then there may be nothing you can do to stop them. As an alternative, you can go with the "Back to The Future" alternative and have a specific date you future self will contact you (the leap year Tuesday is a version of this). A doppelganger who read your future self's mind would already know this, though, along with all your plans, and you would be screwed. Your future self may also have unknown constraints that stop them from following through on any overly-rigid plan. An interesting challenge would be to re-ask this question from the doppelganger's perspective, after you have settled on the solution, "How can I trick my mark into accepting I am their future self?" That might be a storytelling question, though. [Answer] Make PAS into FTS (Warning, possible paradoxes ahead.) When FTS comes you with this incredible knowledge you completely ignore them and ask for them to take PAS to the future to verify that knowledge yourself while FTS stays behind. In the future, PAS verifies the information using the technology of the future. At this point PAS becomes FTS and returns to the past to tell the original PAS about this incredible information and starts the loop. Since FTS stayed behind to resume PAS's old life, PAS continues their timeline and no one else is the wiser since at most a few days passed while they were in the future verifying the information. [Answer] # Occam's Razor I think what we're looking for is not a failsafe, but rather something with enough complexity that even future you doesn't want to go through the trouble to fake. This approach is already used in current cryptography; passwords are not impossible to guess and neither are algorithms, but they take an inordinate amount of time, computational power and energy. If we assume that the time traveler has infinite resources including time he could probably figure out some way to break any password or verification process much like today, but even a time traveler has a lifespan and limited resources. In that case, multi-matching of fingerprints (not one but all fingerprints), DNA, mind passphrases and even better, objects and totems with specific random information encoded or as part of their structure would together function as a nearly unbreakable password. At some point, we can assume that technology could advance to the point where all could be faked, but even in that case, resources must be used to obtain such technology, and if you make your verification process random and personal enough, the likelihood of future you obtaining all of that technology without multiple trips to multiple possible futures, thus wasting time and energy, is vanishingly small. [Answer] ## Time-lock puzzles There are [encryption algorithms](https://people.csail.mit.edu/rivest/pubs/RSW96.pdf) designed to be easy to crack if you're patient but hard to speed up regardless of how many CPUs you(r adversary) throws at the problem. (The idea is that the puzzle is a sequence of modular squaring operations and at any point the next step depends on the previous one.) To identify your FTS just do the following (of course you should do these programmatically, so you don't actually get to know the key to avoid those pesky mindreaders): * Encrypt the text "I am your FTS" with a random key * Create a time-lock puzzle for the key, set the difficulty to a convenient few decades * Destroy the key, keep the encrypted text and the puzzle * Set your ordinary 1 core desktop PC to start solving the puzzle. Make sure you restart it when the power goes out, etc * Check if your future self has a correct key. Pros: * mindreader-resistant * minimizes the butterfly-effect Cons: * only works if your FTS can keep the key from being stolen * the awkward moment when your FTS shows up with the key on a double-density holographic crystal data storage (that's an age-old standard and should work anywhere!!) and you only have USB ports [Answer] ### Same way I did. (Well prepared to...) I watched situation occur in sci fi so many times as a 15 year old I actually put effort into this problem, and solved this. I guessed if I ever sent a message back in time to me, I'd need a way for past me to verify it, especially as a message with instructions on how to avoid a future disaster will be at best weird and at worst illegal. I mean, if you were in 1920s Austria and someone told you to kill this "Hitler" artist dude, you'd dismiss them as a nut. You're not going to murder a stranger if asked. It's not just time travel, I was predicting message through time would be more likely, but could also be dimension crossing, or if my memory was uploaded to a computer this could verify it really was me in that chatter box. It could also be used to verify if someone could really read my mind. I memorized a 32 character passcode of random letters and numbers, 8 groups of 4, allowing it to be used challenge response styls. The purpose was that if I ever saw a message with it on it I'd believe whoever or whatever followed, and follow its instructions unconditionally. The code has never been written down. So the verification process is basically: * I'm you from the future. * Prove it. Code d * defg * code 2 * 2345 * All 32 * abcdefghijklmnopqrstuvwxyz123456 * ok what do you need me to do? * "kill Sarah conner" Or "Hey theres a note under my door. Abcdefghijklmnopqrstuvwxyz123456. Kill Sarah Conner." That exchange (with alphabet replaced with actual secret) will work on past Ash age 15 or older. I think it means that I never invented time travel, as 3 months later was 9/11. Seems weird that future me thought that was worth keeping in the timeline. Edit: mindreading Mind reading comes in multiple styles. The most likely is the ability to hear what someones inner monologue is currently thinking. My method is safe against that. Past me saying "prove it, code d" doesn't internally verbalize the answer. A mind reader listening to my internal thoughts wouldnt detect the answer. If mind reading is powerful enough that someone can just download it all, or my mind is scanned by technology without my consent, the reader needs to sift through gb of data. Maybe i memorized my passcode to the lyrics of an obscure 90s band, so they better listen to every random tune I've ever heard. Maybe it's from a book, so theyd need to sift through everything I've ever read. The code was memorized in different chunks, so it's a huge challenge to peice it together if you downloaded my brain somehow. And if mind reading is any more super powered, like the cop from Heros, none of us stand a chance against it anyway. [Answer] Taking a more philosophical approach: could FTS really ever be PAS? Like if I think back 20 years, I say to myself "I was a different person then". If I travelled back I would have a hard time recognising myself, so convincing PAS would be hard because we're such different people. As others have said, with (potentially) unconstrained mind-reading and advanced technology, a clone/Manchurian candidate/replicant/solid hologram could be made so indistinguishable from PAS that it might as well be FTS. There's no hard line where PAS turns into FTS, so they're always going to be different people in some way. [Answer] Future Self: Take this camera and wallet. Do not open our wallet before we meet again. Go take some photographs of literally anything you want, get them developed, pick any one of them, destroy the others and the negatives and meet me here with your photograph and our unopened wallet. Self: ... our wallet? Future Self: You will see. Next day Future Self: So you opened the wallet after you chose your photograph, saw it contained two photographs of different ages but identical to each other and the one you actually chose. You are now planning to show me an entirely different picture from your coat pocket in which your current girlfriend Kate isn't naked as she is in the two identical pictures in the wallet and the one in your back pocket - and you did keep the negatives including the one where she is clothed. Does this negative of her clothed match the negative in your inside left pocket? [produces negative] Self: Yes. Future Self: Now sign the back of your photograph in you back pocket then look at the back of the two photographs. Self: I never checked the backs last night. Future Self: I know. Satisfied? Self: The signature is Mickey Mouse and all three are identical including the crease from when I put it in my back pocket, so yes. Future Self: Put the negative in the wallet with your photograph and the newer photograph, and keep the wallet. You will need it when you meet your Past Self in about 30 years. Destroy the oldest photo and everything else. Now we need to talk about ... what tattoo you put on our arse last night as a fail safe when you were drunk. Minnie Mouse, really? [Answer] 1. Put on your Magneto helmet to keep people from reading your mind. 2. Install a cyanide tooth to keep people from torturing stuff out of you. (Either that or train yourself to become really resistant to torture.) 3. Think of a single unique passphrase, doesn't have to be complex, don't write it down, don't speak about it ever (and don't forget it.) Done. ]
[Question] [ Exactly what it says on the tin. Kleeber the warrior is wearing a gambeson and carrying the standard adventurer's gear (leather backpack, 100ft of hemp rope, bedroll, spare clothes, waterskin, dry rations, and the 10 foot pole, some metal knicknacks like a spork, a knife, etc) and some weapons (longsword, dagger, shortbow, arrows). Kleeber triggers a trapdoor in the Dungeon and falls into a 20 foot cube room that seals itself. The atmosphere in the room is pure oxygen and there's no light coming in. He uses a magical torch that doesn't need ignition, just a command word. That was a single-use enchantment and nothing else on him is magical. There is a pump sending more and more pure oxygen into the room. The walls and the pump are indestructible. The pump can't cause too much of a pressure shift in five minutes. Physics and chemistry are the same as Earth. The torch is just a oil-soaked rag around a stick. Please note that the adventurer setup is just for ambiance. You could just as well put a redshirt cadet in a forcefield chamber with the same objects and the question remains the same so long the atmosphere remains pure O2. Assuming that nothing else caused sparks before the torch is lit up, what happens in the first five minutes? [Answer] ## Apollo Fire and Wick Effect I generally agree with Halfthawed, but I had some additional thoughts on the matter. There is one well known and documented incident with fire and people in a pure oxygen atmosphere: the 1968 Apollo 1 accident. > > The fanatic overexaggerated fear of a pure oxygen atmosphere is rooted in the horrible 1968 Apollo 1 accident where while ground testing a fire broke in the pure Oxygen environment of the capsule burning the three astronauts alive. It is a common misconception that NASA switch to Nitrogen-Oxygen mix as a result of the accident, in fact, the Apollo Program continued to use pure Oxygen air till the last mission, Apollo 17 and use the mix on the ground, switching to pure oxygen on the rocket ascend to orbit. > Another misconception is that the Apollo 1 inferno is solely the fault of the pure oxygen atmosphere, the reason the fire break out and burned the astronauts alive is caused by the ground testing conditions. The lunar command module was over-pressurized to 1.2Atm in order to check the module tolerance to 0.2Atm pressure gauge it will endure in space. The combination of 1.2Atm of pure oxygen and the full gravity of Earth that induce convection currents feed the flames with oxygen and remove the carbon dioxide created the perfect storm that consumes the module and the astronauts. A low-pressure pure Oxygen is still dangerously flammable though, the air contains as much Oxygen molecules as Earth atmosphere but without the damping effect of the inert Nitrogen, any flame ignited have the potential to evolve to a major fire. - Atomic Rockets [Sidearms](http://www.projectrho.com/public_html/rocket/sidearmintro.php) > > > Another thing that made the Apollo Fire so bad was that the astronauts and the equipment were "soaked" in oxygen. The higher than normal ambient partial pressure of the oxygen (1 atm compared to 0.21 atm) makes the oxygen [diffuse](https://en.wikipedia.org/wiki/Diffusion) into the human body and your adventurer's equipment. This creates a very bad fuel + oxygen mixture. Now let us consider the odd cases of [spontaneous human combustion](https://en.wikipedia.org/wiki/Spontaneous_human_combustion) and the related [wick effect](https://www.slideshare.net/arzbmad16/wick-effect). Normally this wouldn´t be an issue for a living human as the fire starts really slow and incinerates the body over hours ([see video](https://www.youtube.com/watch?v=cilvOCBXI1c), warning pig carcass), but since your adventurer is soaked in oxygen and might be clumsy/unlucky with the brightly burning torch, the fire might overwhelm him and will continue to burn him until [only ashes remain](https://www.youtube.com/watch?v=tIyvB2nxaD0). The fact that more oxygen is pumped into the room makes the fire event more likely. He might die a horrible death. However, I think it is more likely that oxygen-poisoning will get him as the partial pressure of O2 in the room increases. He'll most likely throw away the torch in shock as it gets hotter and brighter. Again, if he isn't careful a spark might hit him and he'll have to fight his burning equipment as he gets soaked in more and more oxygen. This path too will lead to a corpse looking like that of a spontaneous human combustion victim. I'd include a picture, but these are somewhat gruesome so just google them yourself. [Answer] The torch burns quicker. A lot quicker, [but you won't get a violent explosion](https://www.angelo.edu/faculty/kboudrea/demos/burning_splint/burning_splint.htm). Fire requires three things - heat, fuel, and oxygen. You've increased the oxygen, but you haven't increase the fuel, so all will happen is that the torch will burn out far faster - if it lasts for 10 minutes, it might not even last for one. The oxygen won't ignite itself. Something like 2:1 hydrogen gas to oxygen, on the other side, would be far deadlier, but that's not what's in the room. That's what happens to the torch. The adventurer gets [oxygen poisoning](https://science.howstuffworks.com/question4931.htm) because the 100% oxygen gas is not at low pressure and will probably die from a seizure if he stays in the room. EDIT: To clarify, the oxygen poisoning will occur within five minutes of breathing 100% oxygen at 1.0 amu for five minutes, death will only occur if you stay in the room for longer. The oxygen poisoning will wear off by breathing normal air. [Answer] ## Regarding Oxygen toxicity This is rather an extended comment with some calculations than an actual answer. I'd like to back up the matter with some actual calculations. I presume you mean a $20ft \times 20ft \times 20ft$ room when you say "20ft cube room". That means we have a volume of $V=226.5m^3$. Let our initial pressure be at $p=p\_0\approx 100kPa$. Let $j$ be the volume flow per second of oxygen entering the chamber. From the ideal gas law we can then estimate how fast we will reach a critical level of oxygen pressure, [as was linked in other answers](https://science.howstuffworks.com/question4931.htm) and is more than 4 times atmospheric pressure. $$\frac{p(t)V}{n(t)RT}=\frac{p\_0V}{n\_0RT}$$ where $n(t)=\frac{j\cdot\rho}{M}\cdot t$ with $\rho=1.429 kg/m^3$, $M=0.032kg/mol$ and of course $t=5min=300s$ and $p(300s)=4p\_0$. We can now plug everything in. We can calculate $n\_0=\frac{p\_0V}{RT}=\frac{100kPa226.5m^3}{8.314J/(K mol)293K}=9298mol$ $j=\frac{4Mn\_0}{\rho t}=\frac{4\cdot 0.032kg/mol \cdot 9298mol}{1.429kg/m^3\cdot 300s} = 2.78m^3/s$ So our pump will need to put at least 2780 litres of oxygen per second in the room at a constant rate in order to reach a potentially deadly level of oxygen just by the end of the 5 minutes. [Answer] The torch will burn much faster & hotter. There's a fairly common real-world example of this: the oxyactylene torch used for welding and cutting ferrous metals. Light it with just the actylene turned on, and you get a rather cool yellow flame that smokes a lot (rather like your adventurer's torch). Increase the flow of oxygen, and it burns with a hot, blue-white flame. <https://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting> [Answer] # Nothing of Note, Sorry. Thus far almost everyone has been mesmerised by the Red Herring of oxygen toxicity. Given the time constraint of the query and given the chemistry of the experiment, I'm sorry to say that every answer, including the accepted, that involves toxicity is going to fail a reality check. Rationales: 1. Let us not forget that Kleeber the Klobberer is bringing in a N2 soaked micro environment of his own. His own clothing, his hair, his bed roll, his barbarian hat, his spare clothing, the rope --- none of that is going to be instantly saturated with pure O2 inside of the time frame of the query. 2. Once he tumbles into the chamber, the N2 micro environment that surrounds him will create a kind of (temporary) shield. Once he realises it's dark and lights his torch, that N2 will serve as a buffer between the Rumelian candle of his torch and his own combustible gear. Surprise at the bright light and flame will most likely cause Kleeber to throw the torch across the room, thus giving him distance from the fire source as well as gaseous armour. 3. No one has yet taken into account the products of combustion. Once Kleeber enters the chamber, thus setting off the five minute timer, the (metabolic) combustion happening within his own body is going to pump CO2 into the atmosphere. Being an uncouth warrior hero, if he lets off a couple decent farts, he's going to pump quite a bit more CO2 and N2 into the atmosphere. Once he ignites the torch, the combustion of the oil, cloth and wood is going to rapidly emit a considerable amount of CO2 and H2O into the air. Wood emits [the most CO2](https://www.volker-quaschning.de/datserv/CO2-spez/index_e.php) of any common fuel, I've read 1900g of CO2 per 1000g of wood. A standard adventurer's torch weighs in at about 3 kg or so, which will make for a rapid infusion of nearly 6 kg of CO2. 4. Oxygen toxicity, as I've stated in other answers, is a thing. However, given the time frame of the query, it's just not of concern. It takes a while --- more than the five minutes allotted by the experiment --- to obtain relatively mild symptoms. Much more severe symptoms of course will occur [as the time exposure is increased](https://en.wikipedia.org/wiki/Oxygen_toxicity). Kleeber isn't going to be in this environment for a long enough time to suffer any serious reaction to the O2. Conclusions: * The initial conditions of the experiment, a pure O2 atmosphere, will be altered once the subject enters the chamber, bringing in outside & inert gasses such as CO2, N2 and even H2O plus traces of other atmospheric gasses. * Fire in an O2 rich environment will release CO2 very rapidly, changing the chemistry of the atmosphere. Perhaps not enough to prevent oxygen toxicity *over a long period of exposure, but sufficiently, perhaps, to keep our hero safe for the short duration of his exposure. As the wood of the torch is consumed and converted to CO2 & H2O, the subject will no longer be in a pure O2 environment. The wood will be consumed and the fire will self-extinguish. There will be little risk of clinically adverse oxygen poisoning within the given time frame. A final consideration: * Depending on the flow rate of the O2 pumps, Zappo's Thaumic Adignificator, might just get blown away on that 2780 l.p.s. gas flow without ever even lighting the torch! In that case, Kleeber won't risk possible combustion at all, and while the O2 levels will generally be higher for the duration of the experiment, his imported micro environment and the five minute limit will still keep him safe from oxygen poisoning. [Answer] A violent, rather sudden death. When you are unsuspecting, you usually do not hold a torch with the burning end as far away as possible. You hold it in a comfortable position, so it will be maybe half a meter away from your head. It's dark and unsuspecting Kleeber wants to see, so he summons that torch, in a normal, comfortable position. The room was filled with 100% oxygen, and a pump keeps pumping extra oxygen into the room. That was happening during the, say, 5-10 seconds (probably more like 20-30 seconds!) while Kleeber was recovering from the fall, and getting up on his knees, too. So the room is not just filled with oxygen, it is filled with pressurized oxygen (... of unknown pressure). I'm neglecting the volume that Kleeber's body displaces, we can assume some oxygen went "out" when he came "in". The torch, which is not very far away, will thus flash very brightly. How brigthly depends on the actual pressure and is pretty tough to tell, but let's just say it's worth a torch 5 times as big. That's probably not an awful exaggeration. No, it will not explode. But it will give off a considerable amount of very, very uncomfortable heat. Note that normally there's smoke and such (and flue gas is in principle burnable, only just there's normally not enough oxygen, except... think of the famous "Backdraft" movie). We don't have that here, it all burns up, there's plenty of oxygen. So that will mean that not only Kleeber's sleeves (the leather parts will be only superficially oxygenized, but the cloth parts will be soaked) will catch fire, but also Kleeber's hair, which is a desaster. Not only because violently burning hair which wraps your head (possibly including respiratory paths) in a fireball is a definitely no-fun condition, but also because the sparks of burning hair will set everything else on fire, too. There are documented cases of smokers who had such a funny surprise when lighting a cigarette while wearing an oxygenator. Now, that's a joke compared to what your poor Kleeber is experiencing. High levels of oxygen, especially under pressure, can do miraculous things. Things that will not burn at all normally all of a sudden are not as reluctant to catching fire as you're used to. There's documented cases where firefighters took an hour or two to take out a "petty fire" which they'd normally kill in seconds, solely because there was an open oxygen tube involved. [Answer] Reframing - the problem is not the torch, the problem is the oxygen. # Oxygen Toxicity You've got an 100% oxygen environment, into which you're introducing "more and more" oxygen. Kleeber's main problem is going to be [oxygen toxicity](https://science.howstuffworks.com/question4931.htm). Lung damage, CNS damage, retinal damage. You will also get some fairly spectacular fire, but that shouldn't be Kleeber's main concern, even if it's the most obvious. ]
[Question] [ In my world anyone can use magic with the proper training. There are two levels of magic users: * The first level is apprentice (someone with 4 to 8 years of magic education). They can move people and medium size objects with their mind, sense what a person is feeling, and they have limited control over one of the elements (earth, fire, air, water). * The second level is master (for this you must have between 20 and 30 years of training). They can move large objects such as buildings and large boulders with their minds, read and control the minds of others, control all four elements and summon large storms or earthquakes. My question is this: given how powerful the mages are, how can the kings and lords of the land prevent them from uniting together and taking over the world? The tech level is same as that of the early colonization of America. [Answer] How do you keep people who've taken over the world from becoming mages? Since anyone can learn magic young members of the nobility would routinely study magic. Being able to read and control the minds of others is a hell of an advantage for a king or any senior noble. In this world since anyone can learn but only those with the money and time for training can become really powerful whichever way you spin it the nobles are going to make themselves mages even if nobody takes over. Which gives us the answer: The mages won't revolt because the richest and most powerful people already running the country will have trained as mages already. If you were king in this world you'd be sending your kids to learn magic and taking your own private classes. Some mages might be more powerful than the king but at that point they're either invested in the system or are facing hundreds of powerful mages in the nobility who are invested in the system. According to your answer magic isn't powered by anything external, it comes from themselves so you can't strip the manna from around mages. If you want it to turn out differently you need to change the rules for who can use magic and how in this world. [Answer] I feel like there is a flaw in the logic of your premise. If, as mentioned in your setting, `any one can use magic with the proper training` what's to say that your kings are not already mages. I would personally find it hard to believe that they are not trained. In the pre-industrial world education was considerably more limited and focused primarily on the upper classes. Odds are with the amount of training required your nobles/leadership caste are going to be mages more often than the common folks anyway. Its hard to study magic when you are a subsistence farmer trying to survive. In short...odds are your leadership ARE going to be mages --- Section 2 To expand on this from our conversation in the comments... It is unlikely that kings would become full blown master mages due to what appear to be quite stringent training requirements for becoming a mage. Most leaders would have some degree of magical training and a few would have the opportunity and inclination to become masters (Some dad's just wont die!). On the flip side few mages are going to have the world experience and general education that future kings are going to receive. In this case the ridiculous amount of training to become a master may end up being what keeps mages from taking over...they wouldn't even know what to do with their power. This could lead to a couple take-over attempts by mages that end up going horribly for the kingdoms and the mages that take over. Over time they realize that maybe it just makes more sense to let the kings rule... [Answer] Try the Pratchett option > > Hand any two wizards a piece of rope and they would instinctively pull in opposite directions. > > > If they could co-operate they'd take over the world in a couple of days, but that would mean sharing power. They're too busy struggling among themselves to actually care what anyone else is doing. --- The quote in full (Sourcery): > > The reason that wizards didn’t rule the Disc was quite simple. Hand any two wizards a piece of rope and they would instinctively pull in opposite directions. Something about their genetics or their training left them with an attitude towards mutual co-operation that made an old bull elephant with terminal toothache look like a worker ant. > > > [Answer] No time for such mundane matters A profession that takes 20-30 years to master is going to take a significant amount of upkeep to maintain that level of expertise. Almost all of a master's time would be devoted to meditation and continued study of the magic arts. Taking time away from their study to deal with political matters or military conquest would drastically decrease their power. For a real life example, look at the [budō](https://en.wikipedia.org/wiki/Bud%C5%8D) martial arts, such as [kyūdō](https://en.wikipedia.org/wiki/Ky%C5%ABd%C5%8D). Although originating in samurai combat training, some schools of kyūdō also have a spiritual aspect. They teach self-discipline and to involve oneself completely to the art of shooting, very reminiscent of Zen philosophy. Applying this to your world, you could have your mages constantly seek perfection in their art. To sully themselves with political affairs or to use their magic for destructive means would defy the foundations of their teachings. [Answer] Create a legend to protect the Royalty's claim to the Throne. In ages past, when great monster's ruled the realm, Magus The Mighty worked a wonderous enchantment, entrapping the great beasts behind a wall of impenetrable force and burying them deep beneath our feet. He saved us from the creatures who would make us food. But he did more than that! He searched across the land until he found a young boy of noble and righteous countenance. Then he worked the boy's blood into the spell so that the wall would hold, only as long as the boy or his lineage ruled the land. Magus created our First King and set him on the throne which his line must keep, lest the monsters return to our lands. In doing this, Magus saved us again! This time, from the monsters which we spell-casters might become! [Answer] Kings and Queens are the descendants of warriors and leaders of warriors who conquered the area. In a world with magic, warriors mean mages. By the time you build up a large civilization, the combat capabilities of an individual pale before the coordinated combat capabilities of a trained military force. Technology and techniques will be developed for the use of magic in mass-warfare, and governments who arrange for effective use will dominate, and those who do not will be conquered. At colonization of the americas equivalent stage, I'd expect the equivalent of Britian's empire would be fueled by mass magical education, where they crack the technique required for anyone to become a mage, and maybe ritual mass-combat magic, where even relative apprentices can be leveraged for mass magical effects, and industrial magic. If a civilization figured that out, while others did not, it could experience something like the UK's industrial revolution (where a small island dominated the world). Others would start to copy it (but, mass education requires mass educators, and the social structure of a state where almost everyone has magic is going to be different from the typical magocracy) so this is going to take decades to catch up). Meanwhile, at the top, the monarch is likely to have some magical education. But they need not be a top-tier combat or industrial mage: their power comes from the huge mass of the state, not from their individual magic. They are likely to have combat mage bodyguards, much like the monarch is going to have elite guards. Rulers of monarchies in the age of steam where not expert engineers or top-notch warriors. They usually had some military experience and a good education, but that was to season them: their power did not flow from their personal prowess. The admirals and warriors and engineers served the crown, they did not rule it. So I'd build the world where most of the world magical education is limited to the nobility, and are secrets passed down in families. The rising power has created a mass magical education system, where even peasants are taught narrow types of magic be more productive, and every soldier (often drafted from the peasants!) is a combat mage capable of helping in mass combat ritual magic and individual skirmishes. All backed by industrial-scale mass production of enchanted goods (even if they are just "modern" strength alloys). [Answer] Maybe you only can activate magic powers if your heart is pure, and your heart is pure only if you are completely free from ambition for worldly power? Or of course, maybe magic demands "mana" and mana is a scarce resource, requiring that wizards live in limited areas, close to the sources of it? Or the warlocks know that they would struggle for power against each others, with ruinous results, so they have a pact among them that they will refrain from it? ... or... perhaps the mages already do have the power, but prefer to pretend not, for reasons of better using/enjoying it - and the power of kings, lords, and other laymen, is actually an illusion? [Answer] Do what happened in Great Britain during the Dark Ages [Witch hunt](https://en.wikipedia.org/wiki/Witch-hunt). Incite fear of magic, claim it is evil, corrupt or devil worship and will bring death to you and all you love. Have a reward for either capturing or killing someone who practice the cursed arts. Or If you want a reason for the mages to not try and take over the world, then make it so they don't care for money/power such that a king or lord has, they are after knowledge and improving their own ability. Mages may not want to share what they have learnt with other mages for fear of it being used against them. [Answer] You've only described the strengths of the mages. If you want to change the balance of the game, you should give them some weaknesses also. Here are some ideas for weaknesses: * Channeling time: The most powerful spells could take a long time to cast, (e.g. days or weeks) leaving the mage defenseless while they channel. * Cooldown time: After casting a powerful spell, the mage would probably be weakened and unable to do much for several weeks. Study what it's like for someone to recover from surgery. * Mana cost: As someone else mentioned, you can introduce the concept of mana as a scarce resource which might be hard to find, or maybe it's easy to find but it takes a long time for you to get enough of it. * Maybe the telepathy backfires on the mages, and normal people can sense the presence of their telepathic mind, making it impossible for a mage to hide from an angry crowd with pitchforks. Mages are persecuted and have to live far from the non-mages, in their own small groups. [Answer] It would seem to me that your description of magic is a little simplistic in the question from this standpoint. It seems almost as if you're saying that strength is based only on time put in, sort of like the way unions might promote a member from apprentice to journeyman with minimal accepted skill level + minimum number of years of experience. But just like there are generalists and experts in carpentry and plumbing, there would be generalists and experts in magic. One could be a general master mage which would mean, they have the experience to safely do advanced level spells, but maybe not all of them based on their discipline of study. Requirement for Mastery of magic might mean 20 years, plus the ability to cast safely and sufficiently strong a set of master level spells in each of fire, water, air, and earth diciplines. However, there may be more than 5 master spells each. In fact the master generalist can safely explore the master spells, but might not bother mastering all the master level fire spells because his interest lies elsewhere. It could also be that there are hidden/rare/ultimate spells that are kept from the general public and invested in royalty/ruling class that are only know to those of highest government wizard rank. Not having access to, or in fact, knowledge that certain spells exist could be one way of controlling them. Another might be wealth and/or the existence of mana/runestones/wands/objects of power that might be licensed or sold by ruling class. If someone were to say requisition a huge amount of mana potions(or whatever) in a short period of time, it might raise red flags to watch said individuals. Then there is just human nature. Those that strive for power, inevitably don't want to share it. It would be difficult to gather together a group of power hungry wanna-be-take-over-the-world mages together without them starting to squabble, duel or otherwise fight amongst themselves. Then there could be some magic or artifact that the rulers have that could negate magic(perhaps the castles are all erected on anti-magic fields) or have null magic shields that prevent any spells from entering. This is sort of like the steadings in the Wheel of Time series of books. Magic just doesn't work there. Then it also could be that magicians are by their very nature sort of like the stereotypical "mad scientist" who tend to be more interested in the "science" or "magic" itself rather than application or consequences of said experiments. Finally, it could just be a matter of you got your mages and the government has theirs. They might try to take it down and the government has some teeth to prevent it(not always working, after all just like governments take over each other in real life). Brian [Answer] > > given how powerful the mages are how can the kings and lords of the land prevent them from uniting together and taking over the world? > > > Who's to say they haven't already? Given the kind of society you're describing, I would expect that there would be powerful mages lurking behind the seats of power, pulling the strings. The kings and lords may think they have power, but the real power lies with their trusted "advisors" who manipulate every major decision toward their long term goals. [Answer] To prevent mages from taking over, you need to create real obstacles to becoming a mage. Say for apprentice level, you need to spend a year in a cave, learning how to channel the magical energy. And if you fail you may die. For master level, you need to spend 10 years in such cave. While other mages (employed by other powers) might try to detect and interfere. [Answer] To be a king, to rule, you have to be able to inspire the people. It's very unlikely that a Mage would have the charisma or be a people person given the level of solitary study required. Rather like Steve jobs, techno wiz but no ambition to be a politician. While trump couldn't change a fuse but can inspire people to vote for him. Of course, a Mage may rule the world through a puppet King... Mwahaha :) [Answer] As Ronan and some others said, the Discworld offers some ideas here. The Discworld MUD has gone through this too and they balanced off magic use quite nicely I think. One reason that wasn't mentioned is that magic on the disc is (1) dangerous as it is unreliable and has a mind of it's own which can easily backfire and kill the caster. More powerful magic = higher risk (2) is a little inconvenient to use as it often requires components and ingredients you have to carry around on you. [Answer] There have been a lot of good answers, and a number retreading the same ground. I'd just like to add one more. Consider adding a Bane. Something antithetical to magic. Like the classic, Cold Iron. Iron forged without getting above a certain temperature (say, it can be heated but not to the point of actual visible glow). Cold Iron sinks and dispels magic with 100% efficiency. So a Master Mage can crush a castle and burn an army with a wave of his hand, but a single warrior wearing cold iron plate and carrying a cold iron sword is immune, possibly pulling and grounding out spells like a lightning rod, protecting those around them as well. A king or queen keeps at least a small elite guard equipped with the magic bane, a royal crown is lined with small amounts to protect the lords and ladies minds from being controlled, and so on. [Answer] Sheers numbers. Wizardry takes a lot of time in your world to be truly powerful. COnsider this similar to a PhD in our world. Only a small percentage of the world population has a PhD, so it would follow only a small percentage of your worlds population would be master level wizards. Sure, a master level wizard could kill 1000 men. But could he kill 10,000? 20,000? Eventually, a master wizard could be taken down by enough men if they stepped out of line. [Answer] You should watch the X-men movies through. The mutants are essentially mages, and indeed, a group of them, led by Magneto, basically keeps trying to take over the world. Humans don't stand much of a chance against them, there's only another group of good mutants that can successfully do that - - the X-men. The X-men believe in peace and coexistence with humans. Many humans, however, do not understand the mutants thus fearing them and thus acting hostile towards them. For Magneto this basically justifies his war. So in your world, why would the mages take over? Have they been given any reason to do such a thing? It doesn't sound like that, I gather that they are actually valued members of the community. And like someone else already mentioned, ruling is hard work, many of the mages can certainly think of something more interesting to do. There's also that quote that says that often those who crave for power the most are the ones who are the least capable of handling it. Take some power hungry mage, and you can be certain there are other mages who would much rather not see them reign. So overall I suppose I can summarize by saying that there are luckily more good people than bad people, within mages too. [Answer] Mages are like feudal knights. They are experts at what they do and are devoted to their lord/king/queen. This arrangement is mutually beneficial - mages are given the time and resources to devote themselves to their craft, and the rulers gain powerful allies. The rulers themselves are rarely mages, because the dedication required conflicts with the responsibilities of ruling. However, it is common for the non-inheriting children of important families to study magic, and they become important contributors to the family's strength. Sufficiently intelligent and studious people of lower rank can rise in status by becoming mages - the usual route for this is to seek patronage from an important family, and then repay them with service. Self-taught prodigies are extremely rare. Mages who betray their patron are seen as treacherous and ungrateful. Eventually, a "commoner" mage can gain their own lands and start their own noble house, so they are rarely interested in bringing the whole feudal system toppling down. [Answer] When a mage exercises power they are not generating the energy involved, they are only bending and directing what is already around them. Two mages cannot manipulate the same energy at the same time. Similar to [destructive interference](https://en.wikipedia.org/wiki/Interference_(wave_propagation)). The more powerful or skilled or experienced a mage, is the wider an area they will be able to effect in their manipulations. Consequently, they do not want another fully trained mage within their territory. The result is that they don't work together, or even gather together. Getting trained as an apprentice (the only stage the requires formal education, the remainder is up to self study) requires a teacher willing to set aside time where they relax their grip on the ether while the students practice. Even so, dedicated students will find that they need to travel into the wilder areas to gain the solitude necessary to gain skill. This is part of the reason it takes so long. Additionally, a teaching mage will require some exorbitant fees in order to mitigate the loss of time spent within the ecstasy of total mastery of their demesne. [Answer] You specifically note magic education. As it doesn't seem that you have any issues with the nobility being magically gifted as well, perhaps magic instructors are prevented from teaching the common folk or are so rare that the nobility snatches them up as tutors before any old dirt farmer could learn powers that make rebellion a bit more possible. Perhaps the common folk of your world can get somewhere with self study, but you could use this to limit their magic to things that wouldn't assist a rebellion. For example, farmers use their knowledge of water magic to irrigate their farms completely. In addition, perhaps the commoners won't rebel if they don't think they can. Have the average citizen believe magic is only for basic support and making lives easier. Perhaps the kingdom has instituted public education to teach just that, at schools or churches. Thus the common folk live believing magic is a convenient tool, and the nobility can rest easy. [Answer] If you look at the world we live in, the world is not taken over by those with the most physical prowess, not the smartest (arguably), and not those with the most refined social skills who hold the power. > > Power resides where people think it resides. It's a trick > > > Power is largely held by frail old men with weired quirks and poor behaviour. It's more a matter of intent and being in tune with the intent of the group mind. The mages in your would would probably - most of them - be instruments of someone else actually making plans and holding power. [Answer] Why isn't the most powerful person king of everything? The same reason why the best fighter in this universe isn't the king of everything. Being a fighter is hard work. You commit your life to it. Being a king is also hard work. You commit your life to it. If you need to fight, you get a whole group of top fighters to fight for you. You can't be a good fighter yourself, you're too busy running a kingdom. [Answer] The question is moot, because it cannot happen. There is a symbiotic relationship between magic and goodness. Look at the grand magic that Jesus pulled off, water into wine, parting of the seas, etc.. But the best example is of course God. The creator of life itself, there is no greater magic trick than something from nothing.All that was created in goodness. The goodness is so entwined with the magic that one cannot exist without the other. A simple example of reading another's mind is impossible without the honesty needed to communicate on that level. If the motive was to take over the world, then that would poison the attempted mind communication to an extent that the mind reading [earthquake, bending spoon, interstellar travel etc..] simply would not take place as the energy is bad, like trying to run an electric car on sand, it won't work. This was the fail-safe code written into magic by God. It must be good or it cannot happen. If you want to be a grand master of magic, first you must be a grand master of goodness. If you are, you will not want to take over the world. [Answer] A simple way of preventing mages from just overthrowing everything is to make them vulnerable. I propose adding some such problems, they work on their own but in combination they are lethal to mages who get rebellious ideas. In order of importance * Make it really obvious to anyone when someone uses magic. I would make it so that even untrained people would sense when a mage cast a spell (say within twice the casting range) and allow other mages to trivially identify exactly which spell and what the targets and other parameters are within 10 times the casting distance. * Ensure that there is no magic that easily protects from a well placed arrow * Dissalow affecting things you can not see or in some other way sense * Disallow or restrict magic enhancing the senses, so that a mage can not sense things more easily (adding senses like read thoughts is ok, but not improving existing ones) This combination of restrictions makes mages vulnerable to anyone with a bow and better eyesight than them. I would envision that this makes mages valued members of any despotic system of governance while still allowing for non magic users to be at the top, a king can just order them shot on sight in the capital if he is paranoid. [Answer] 1. Casting time: how long the spell takes to cast 2. Mana: how often you can cast spells 3. "Miscasting": Your head explodes because you swapped a syllable or got distracted. 4. Eldritch Beings: scary creatures that are drawn to magical power 5. Weapons designed to kill magic users, made by other magic users, ironically 6. Range: anything less than the range of a bow and arrow and you have a problem 7. Rarity of Books: books are rare and expensive 8. Misinformation: Some/Many/Most books on magic have "traps" written in... 9. Shady Guilds: anyone whose not a member has a bounty placed on their head. 10. Etc. ]
[Question] [ In my sci-fi world, mankind has begun colonization of the large asteroid Ceres. There are several established towns on the surface, but most of the population live underground in icy/rocky caves. The major industry is mining and exporting water-ice. Ceres is undergoing a rapid transformation from primitive mining backwater into a trade and refueling hub. It's becoming a focus point for belt mining, and a major supplier of water-ice and precious metals as mankind starts to explore the rest of the solar system. There are a few orbital fuel depots and repair facilities now, and large trading ships come and go frequently. Many see a chance to make their fortune by going to Ceres for a few years to try to strike it rich. My story follows a pilot, who does short surface to orbit flights. He's a delivery boy basically. He's poor, with little opportunities, stuck in a dead-end job, working long hours for crappy pay, and he's doing it in a leaky, worn-out ship held together with duct tape. I am really trying for a realistic feel to everything, with one concession for style: I love retro tech! I want the spaceship cockpits to be filled with switches and levers, analog dials, and gauges, and I want to avoid computers, holograms, and anything high tech as much as possible. The ship is cobbled together from spare parts and ingenuity. Higher tech equipment can and do exist in my world, but just not on-board my protagonists spaceship. How can I explain the lack of more modern, convenient technology? I want to focus on astro-navigation, where my protagonist flies with the use of a sextant, stopwatch, observations, and maybe a primitive computer to do basic orbital mechanics calculations. It's all seat-of-the-pants flying experience. A GPS satellite system seems likely and economically possible to build around Ceres at this point, but how do I explain that my pilot doesn't have a GPS receiver on board, or a laptop or tablet computer capable of drawing 3d orbital paths even? I wish to keep the description of the pilot character to an absolute neutral minimum, so no weird religious beliefs. He's an average Joe in all ways. A good answer to this question will explain and support my stylistic decision to only have primitive mechanical instrumentation available on the protagonists spacecraft (think 1960s space tech level) in an otherwise future sci-fi scenario. Radio receivers are ok, as are radar and the kinds of instruments you'd find in a light aircraft cockpit, but I need a way to explain the absence of computers and screens. These things would likely be affordable even for the most humble of vehicles. So why are they not available here? [Answer] ## The licenses are too expensive If there's mining on Ceres, it's probably run by big corporations. In an effort to control the colony and all activities in the belt, the corporations have introduced/lobbied for laws that strictly control space ships and all electronics with everlasting patents and costly licenses to allow use. These are ruthlessly enforced with EM-scanner equipped patrol ships. After a number of ships were abandoned on Ceres with the owners jailed or executed for falling behind on payments, some enterprising colonists stripped out all patented electronics and replaced them with pre-patent tech. The corporations tried to outlaw that as well, but suffered a narrow defeat against the "right to fly" movement. That made the basic propulsion tech free to use for all. Some years later, these free flyers have found a niche running odd jobs for corporations and private people unable to afford proper transport. Of course, they also provide a good deniable method of transporting things the corporations really don't want to be associated with... The scenario can be modified to suit your taste: * The protagonist might be the first or only one to have exploited the loophole. * There could be tiers of technology licenses available, resulting in ships with varying levels of tech on board, from levers and vacuum tubes to screens to AI piloted ships. * The use of EM-emissions scanners might be the primary means of detecting ships in the asteroid belt, since it's fairly easy to pretend you're an iron-rich rock when radar is looking at you. This gives smugglers and the protagonist a very good reason to go low-tech. [Answer] Maximum security (or paranoia, if you prefer). Rightly or wrongly, your protagonist believes that someone might use more advanced technology as an avenue to take over the ship or otherwise do him harm. All the controls are manual so that no one can take command away from him. All of the data displays are analog so that no one can use them to figure out where he's going or where he's been. If he has a computer, it's just for crunching numbers and charting the odd orbital path (and doing his taxes) - when he arrives at a course, he makes sure to double-check it before entering it by hand. Since you specify that you don't want this to be a personal eccentricity on the part of your pilot, you should figure out why he and/or his employer would be so worried. Maybe the government has a habit of spying on ships and seizing those involved in shady business. Or maybe they have some cutthroat competitors who wouldn't be above staging an "accident" if they had the means to do so. [Answer] A computer screen takes power. A physical switch, on the other hand: A) Can display its state with no power needed B) Provides physical feedback when used, or can be checked by touch when looking at something else C) Can't suffer from a glitched display showing the wrong information That physical "clunk" of disabling exterior vents before exiting atmosphere is reassuring. A weedy "beep" doesn't have quite the same tactile response. Also - have you ever tried looking out of a window at night, from a brightly lit room? When trying to avoid crashing into another spacecraft, you don't want the viewport to be covered in a bright reflection of your monitor. As for GPS? Well, [GPS can be spoofed](https://en.wikipedia.org/wiki/Spoofing_attack#GPS_spoofing), and some of the cargo he delivers is valuable to other parties. This lack of reliance on GPS is one of the reasons that your character is seen as a [safe and secure](https://electronics.howstuffworks.com/gadgets/automotive/car-gps-accidents1.htm) transportation method [Answer] Love the answers so far! One option I haven't seen yet, though, relates to the nature of Ceres as an environment, both physically and economically. Because of Ceres' low gravity, you don't need to make a ton of complex calculations: you can escape the gravity well pretty easily with a minimum amount of fuel. On our world, we think of getting to orbit as more complicated than flying a plane, but that's because Earth's escape velocity is so large that it takes a lot of work to get there. On Ceres, though, things aren't nearly so difficult. Basically, to go from surface to orbit, all your protagonist needs is the spaceship version of a rowboat. As such he doesn't need a lot of bells and whistles. He's basically in an airtight room with some thrusters attached. Everything can mostly be eye-balled, so just point your nose towards the blinking light and press the gas pedal. No need for computers, and in such a situation, you don't want a bunch of displays; something dead simple, easy to repair, and with hardwired redundant systems will win the day every time. Around Ceres, all those electronics would merely be a distraction. Now, why doesn't he have at least a smartphone? Why can't he use GPS? Simple: economics. The OP says that computers and screens and such are cheap even for the humblest of craft in his universe, which I think may not be an accurate assumption (remote areas have to import everything, which makes everything expensive – all the more so fancy electronics), but for the sake of argument, let's just concede the point. Even if he has a smartphone, it may not be terribly useful. From a smartphone maker's perspective, Ceres is not what you'd call a 'large market.' Why, then, should you mass produce devices that work in the Ceres environs? Rich people will pay you to make custom versions with high precision scans of Ceres and all the other inhabited asteroids, custom features, and AI flight controls; they can probably make a ton of money outfitting space yachts. But to do that for some asteroid dweller who can barely afford food? Why even bother. Maybe, even, he has a smartphone, and it can pick up GPS signals. Unfortunately for him, though, Google Maps is made for earth, not Ceres, because, again, not enough of a market for that. As such, it doesn't even have a map of the surface, let alone being able to locate you on or around it. So, to sum up: 1. He's driving a space rowboat. 2. Most of the spaceflight he's doing can be eyeballed 3. Electronics in his price range aren't helpful, and are probably just distracting. [Answer] Trying to go in a different direction here, I would suspect the reason to use analogue equipment and jury rigging is that the space environment is seriously hard on digital equipment. There are no fabs or chip factories on Ceres or anywhere else outside of Earth because the vibrations from launching manufacturing equipment into orbit seriously degrades the equipment. Optical masks no longer are in alignment, which makes building chips to micron level precision impossible, for example. Similar effects happen to high end 3D printers and other advanced forms of manufacturing. Once you are on the Moon and beyond, the only way to make "new build" equipment is to use industrial techniques from the mid 20th century-lathes, milling machines, welding, riveting...locally sourced electronics are vacuum tube for many of the same reasons. Because the size and weight of industrial equipment, very few machines are actually being shipped to orbit, so you have the bottleneck of either buying bespoke items built and tested on Earth, then launched into space for you, or hard pressed machine shops with limited amounts of equipment needed to actually build or repair your stuff on Ceres. This would also explain why you actually need humans doing things, buying bespoke robots from Mitsubishi and boosting them into orbit and then to Ceres would be extremely costly, while humans are still far better at general purpose work and can switch jobs in a heartbeat or train to do now jobs long before a new robot can be delivered. So there would be a huge dichotomy between the very wealthiest of people and companies, which can afford to have everything build on Earth and delivered to them, and everyone else who is essentially using the town blacksmith to build things. This state of affairs isn't going to last forever. The tools are being used to build new tools in a geometric progression, and eventually it will be possible to make chip fabs or 3D printers on the spot, but this might take decades due to the small base they are starting with (a few machinists and a handfull of tools), and the fact the industrial base is fully engaged already with keeping the existing infrastructure going. At a meta level, you could ask yourself if factions on Earth are deliberately exacerbating the situation to wring the most profit from the space colonies. [Answer] Fashion. The driving force behind this in real life. The retro movement over the past decade or so has produced many modern cars that have been specifically designed to look old. While they've stopped short of actually using outdated technology (I've yet to see a new MINI with a choke cable), I wouldn't underestimate the power of fashion. That's just mainstream releases from large manufacturers. There's also a growing industry producing essentially brand new examples of classic cars (with only select upgrades). * If you have oodles of money, [Eagle](https://www.eaglegb.com/) will produce for you an updated (but still thoroughly antiquated) E-Type, as will [Jaguar](https://www.evo.co.uk/jaguar/16191/watch-12million-jaguar-lightweight-e-type-driven) themselves (using unregistered chassis numbers from their low-drag project in the 60s). * [Singer](http://singervehicledesign.com/) will similarly liberate you of a small fortune and produce what amounts to a brand new and thoroughly modified classic Porsche 911. * [Pur Sang](https://petrolicious.com/articles/pur-sangs-john-bothwell-on-building-a-modern-bugatti-empire-in-argentina) in Argentina will even manufacture for you a completely ground-up Bugatti Type 9 or Alfa Romeo 8C to entirely original interwar specifications. * If you're not an oil baron (but still not wanting for cash), [Frontline Developments](http://www.frontlinedevelopments.com/vehicle/mg-le50/) will manufacture for you a brand new MGB (again, with suitable upgrades). A similar, or even more exaggerated retro movement at some point in the future could well lead to spaceships being designed using retro technology. 'Evoke the feeling of the first spaceborne pioneers', or some other marketing line ;) Of course, yours being a rickety bucket I expect it isn't one of the megabucks retromods. Perhaps your protagonist owns the spaceship equivalent to a PT Cruiser (shudder)... [Answer] The ship was originally built for an eccentric bajillionaire who wanted it steampunk classy theme. With everything custom made over the years all repairs have been jury rigged temporaryish solutions that just never got fixed properly if they even could since the bajillionaire is long dead and gone. [Answer] Retro fitting a space ship with more modern systems is a nightmare. This holds true already on existing systems. Look at the Space Shuttle or at some airplane or car designed in the late 70es: you will hardly find modern stuffs, even though the whole assembly is still used today (or until few moments ago for the Space Shuttle). If the thing works fine and there are no major issues, it is simply convenient to let it run as long as it can and not spend money in upgrading it. This would especially fit your character: > > He's poor, with little opportunities, stuck in a dead-end job, working long hours for crappy pay, and he's doing it in a leaky, worn-out ship held together with duct tape. I am really trying for a realistic feel to everything, with one concession for style: I love retro tech! I want the spaceship cockpits to be filled with switches and levers, analog dials, and gauges, and I want to avoid computers, holograms, and anything high tech as much as possible. The ship is cobbled together from spare parts and ingenuity. > > > [Answer] ## It’s an Accessability Option The aliens or robots or whoever this ship was really designed for have a fancier way of piloting it, but humans don’t have built in wi-fi or telepathy or the ability to see ultraviolet. Fortunately, there’s a backup system of switches and gauges. It was thrown in only because it had to be, but it’s the lowest-common-denominator every species can use. Not everyone can see the same colors, but everyone can tell that a button is lit or unlit. ## It’s the Emergency Backup The ship came with “manual” overrides, but was never intended to be flown that way on purpose. In fact, a ship with no working computer would be sold for scrap. ## It Only Looks Primitive There’s a computer in the spaceship; it’s just accessed through an analog interface because that’s how people like it. ## It’s Simple and Reliable [Mechanical fire-control problems](https://www.youtube.com/watch?v=s1i-dnAH9Y4) were a solved problem decades before space flight. ## If You Made It too Easy, Any Idiot Would Do It The real danger isn’t human reaction time, or that somebody will fail to enter the right coordinates with his life on the line. Space flights are long and boring, and mostly an exercise in Newtonian mechanics. It’s letting anybody get into a spaceship and say, “Plot a Course for Mars.” Making people perform the basic steps manually guarantees that only pilots who understand the basic principles of space flight can get themselves into trouble. [Answer] ## (Really) bad spaceships can only carry robust devices > > The ship is cobbled together from spare parts and ingenuity. > > > Imagine the engine is good enough to allow surface to orbit flight, but the hull is at the "handwork" level. As a consequence, all devices on board undergo sever shocks and vibrations. Modern electronic components would be able to endure it for a while, but would suffer frequent breakdowns on the long term. Your character is poor, and can't afford to replace his devices on a regular basis. Then, he has to go for technologies less subject to vibrations. He can't afford pieces of electronics dedicated to these special conditions. The only (cheap) possibility for him is to use old-fashioned wires and switches. Realistically, he would have a GPS receiver though. But for the same reason, he cannot entirely rely on it. So, in case of breakdown, he gets in the habit of computing his position and trajectory himself using basic technology. He just uses the GPS to check his results. ........................................................................................................................................................ You can say that he used to employ modern and convenient technology, but had to change his mind over time for these reasons. You can also imagine that one day he almost died because of a GPS failure, which would explain why he only trust "sextant, stopwatch, observations" and his own calculations. [Answer] Maintainability You can replace a lot of switches with a touchscreen and it will save you cost but if your touchpad fails you basically have to buy a new one. If you have switches you can possibly rewire them so that the dysfunctional ones are on non-vital systems. You can also replace them individually which might not makes sense in a proper cost-benefit analysis but might be the only option for people with money problems. User experience You can replace a keyboard with a touchpad but touch typing is almost impossible. I don't know what kind of user interfaces people could eventually get used to but there is definitely a benefit to having simple, tactile things. Cost At least this holds for holograms. Since we don't know how to make them yet, it might still be difficult and therefore costly in your future. Admittedly, none of those will justify the absence of even a basic computer. Radiation Or a similar phenomenon. It doesn't actually prevent electrons from going to and fro but it induces sufficient fluctuations that complicated electronic components get fried. Of course the rich people have 5 levels of fall-back systems to check each others results and enough shielding to not even need it. There might be an issue with this being a problem for humans, too. I have no clue bodies work. :p Sextant Just to point this out, I don't think a Sextant would be a good device for your runner in any case. If you want a mechanical navigation device you can and probably have to devise something better with modern techniques. Even if it's purely mechanical. If your protagonist is only making trips from Ceres to surrounding stations he might also be able to fly by sight and not need a sextant in the first place. After all, a sextant tells you where you are. Given a fast enough ship you don't have to verify your position between leaving from a point which you already know and having sight of your destination. [Answer] He doesn't need it Ceres has a diameter of less than 1000km. Even at plane speeds, you can orbit it in a few hours. If he has been flying long enough, he knows the landmarks. If the settlers installed an artificial magnetosphere to protect against solar storms, he could use a completely non computerised compass to navigate. Whilst you might call it a "spaceship" it's not going interplanetary so it really doesn't need computers, navigation, life support (beyond basic heating) or any electronics. It's little more than a glorified space bus. It will only be out of port a few hours so already contains enough air. Portable scrubbers and spare O2 tanks can be added for longer trips if needed or an emergency one in case of a break down. Any further navigation needed can be done via a directional antenna. He sets the radio to the control tower of the destination and rotates the antenna for the best signal and then heads in the direction of the antenna. One dial to set the station and a crank to turn the antenna and you have your direction. [Answer] Your protagonist is still driving around in a "first gen" spaceship. This would be roughly equivalent of taking really good care of your car built in 1976 and still being able to drive it today even after 500,000+ miles. * New spaceship models come out every year, but your protagonist still prefers using what he already has. * He doesn't need any fancy tech to travel in space, because that fancy tech didn't exist when humans explored space (in this story's universe). He prefers the 'manual transmission' of spaceships. * Most parts on his ship have been replaced at one point or another, making many trips to the space junkyard to keep his ship in working condition. * Your protagonist has extensive knowledge on the mechanics of his spaceship, since he's spent significant amounts of time replacing parts (and using duct tape). [Answer] ## It's how it all started and there was no good reason to change. Every last piece of equipment had to be shipped over from earth. Between the distance and the tyranny of the rocket equation, the hardware had to be reliable, and field repairable, because replacement parts were six months (plus the wait for the next launch window) and fifty million bucks away. Most of this initial delivery of equipment was purely mechanical, because integrated circuits are impossible to fix without clean rooms and other heavy and fragile items that take up cargo space and may themselves be DOA, leaving the crew to die. The gravity of Ceres is low enough to make manual orbital rendezvous a possibility; while the procedure was by no means easy, it was still vastly preferable over being stuck on Ceres because the automated shuttle is broken. So the first shuttles were manual, and have been used and fixed with duct tape ever since. Sure, the settlement has grown since those early days, but that pioneer spirit of "if hitting it with a wrench doesn't fix it, we don't need it" and "keep your toys, we're working" lives on. Why replace a perfectly good manual ore truck with an automated one made by some tech valley nerds on earth for whom their closest experience with a space habitat is the local Starbucks? They don't know what the colony even looks like. Some traces of technology have been showing up lately, but no one is in a particular hurry to use them other than maybe reps from earth who can't live without their creature comforts. Things like those GPS satellites, which turned out to slowly creep out of alignment due to a magnetic anomaly the miners knew about because none of the highly paid software consultants bothered to ask them about the local hazards, ending up overreporting altitude by some 500 feet. After a new automated landing craft came in for a supersonic landing at 400 feet, the miners decided they didn't want to trust their lives to this electronic garbage and continued to fly their old manual barges using their own functional eyes. Sure, they say it's fixed now and can totally be trusted. Yeah right. [Answer] Short answer: ### You can't. Long answer: ### You can't, because seat-of-the-pants flying doesn't happen for orbital mechanics. You're misunderstanding just how sophisticated the 1960s tech was. There's a reason that after NASA had selected America's best pilots and put them in spaceships, they ran those spaceships on precalculated trajectories with no manual intervention. The reason is that the maths behind orbital mechanics is *hard, and trajectories over distances where you can't see the other side are not something which can be done by intuition. The astronauts' skill was only required for the final touchdown of the lander on the surface of the Moon and for connecting the lunar module back up to the command module - everything else was calculated for them by a team of some of the country's best engineers and mathematicians. That's how the 1960s technology worked. Even with sailing ships, the maths to follow the shortest distance between two points on a sphere is notoriously tricky; and similarly the maths to work out your location from a sextant sighting. It's the reason navigation was a skilled job for officers, because it needed a serious level of maths skill. It's easier these days when we have electronic calculators, but you still need to know what you're doing. And that's just for going round a sphere. For sure, if you've got a computer then it can work out the trajectory for you. In which case you can program the 1960s tech with the trajectories which your computer comes up with - and then set it going and sit tight until you arrive at the other end. If you haven't got a computer, you can spend a week doing the calculations for your trajectory - then program it, set it going, etc.. As with the Apollo landings, the only seat-of-the-pants element is with the final approach and landing. The rest of it is all maths, and very hard maths at that. [Answer] There has been a serious problem with rogue AIs and a human-machine war that humans barely won (possibly leaving Earth a blasted wasteland). As a result all advanced computation devices (basically anything programmable) have been banned. [Answer] Tl: DR: Electronics can be hacked, humans can't. Humans are greedy, a series of incidents forces governments and corporations alike to start using more and more human-piloted craft to prevent theft and terrorist attacks. A single drone that is hijacked (during it's mining operation for example) will be catastrophic if it rams an orbital station or a colony. The cost/effectiveness of using pilot instead of drones rises and might be made mandatory. Long version: "Today Mining corporation X reported the disappearance of 2 of it's supply ships. This is a disturbing continuation of the trend with the 4 disappearances that happened earlier this month. Mining corporation X has accused Mining corporation Y of theft, although if these allegations will ever reach court is doubtful..." "Mining corporation Z suffered a malfunction in one of it's mining ships, causing it to ram their orbital station with great loss of life and materiel. Shortly before the incident a strong external signal was detected that is suspected to have hijacked the ship, causing it to lose contact with it's controllers. Spokesmen of Corporation Z have issued their condolences along with open threats to the other corporations..." "To safeguard the international community and trade in space the UN has voted with a large majority that all spaceships should be manned during their flight, so that further drone incidents can be averted. Too little too late according to many of the families who have lost loved one's in the brutal competition gain a mining monopoly. Most of the corporations had already started employing manned ships. The cold statement issued by some of these corporations was simply that the costs of life support and fuel outweighed the potential for theft and destruction a single ship represented..." "The United armed forces are to patrol space and seek out any drone vessle they can find. After two incidents where an unknown mining corporation used unmarked drone ships to destroy large portions of a surface colony and an orbital station. Any ship that looks like it is controlled automatically will be investigated and if need be destroyed. Protesters fear for the quality of life of the pilots that are often stuck for months in a small space. Drones could easily try to emulate human pilots causing a high risk that piloted ships might show up as a false-positive due to it's many electronics. This has prompted the mining corporations to reduce the amount of electronics pre-emptively, severely reducing the quality of life of it's occupants..." [Answer] Extrapolating from current-day technology, I'd suggest that in your future scenario, hacking and spam may have escalated to nigh-unimaginable pains in the ass. Virtually every electronic system may be so infected with spyware, viruses, and advertisements that nobody dares rely on it. Some of the worst malware may be written by pranksters to activate at the worst possible moments, e.g. in the last half-second before landing rockets fire to make a safe landing. It wouldn't take too many incidents like that before people started to study how to make their own calculations and rely on the computers as little as possible. For realism, I would avoid the (2nd) Battlestar Galactica scenario where evil robots hack our computer systems to disable and destroy our ships; it's much more depressingly realistic to imagine a self-induced apocalypse of advertisements, malware, porn, and spam consuming the Internet from within. [Answer] Robustness, redundancy, parts flexibility, system visibility, and human control: You're in space, you have limited resources, and small mistakes mean you die. - Are You* going to trust that a programmer sitting in a cubical back in earth actually double checked his math before punching out on his last day at the company? Build the controls out of small and highly task specific modules with limited functionality coverage - These have been tested for decades, and we know what they do. [This is part of why we're still sending 486 era, and even older, hardware designs to space.] Things like touch screens and complex computer systems are delicate, and not flexible in how they're fit together - while you could cram all the controls into something the size and weight of a small smart phone, fixing it [or spotting faults] in something like that would be difficult. And faults are deadly. - Much like we can build "All glass" cockpits in aircraft today that controls all functionality from a single screen, we still typically fill a cockpit with an array of dials and switches - Because dials and switches don't disappear if a single power cable to the one screen has a fault. And why take manual navigation measurements in place of trusting the 'GPS' [or space positioning system? Orbit positioning system?] - Treat it like some seasoned sailors still do: A handy tool that aids the manual measurements rather than replaces it. Make it a cultural norm to simply not place blind faith in such a system, possibly to the point that pilots even just leave them behind to save on mass and energy usage. [Answer] The just don't make them like they used too (It's a pitch for marketing): Sure, it ain't your daddy's ship. Hell, your grandpappy's ship probably had more tech than this. Heck, I have some gizmos on here that run on Fortran code (for you non-computer geeks out there, Fortran is a programing language and a lot of the code on the Space Shuttle was written in Fortran. It was a legacy lanugage (meaning you only really need to know it if you have to maintain old programs running on it) well before the shuttles were retired.). But I know my girl... she can put down and blast off with the best of them shiny ships... and half the price too... they charge you for the fancy gizmos my girl don't got cause they don't need them. To my mind, pretty and shiny don't mean much when your in the business of getting something from surface to sky and sky to surface. The just don't make them like they used too (It's true as well): Provided you have the parts available (that's where you can have some trouble) or machined for cheap, it's usually easier to fix old tech than it is to fix new tech. Most early cars are rather simple in mechanics and can be fixed reasonably well on the cheap and on the fly. A modern car will need a laptop coumputer to calibrate all the computers that are controlling things humans couldn't for maximum efficiency. Not to mention, a lot of tech does have several generations of backwards compatibility with older equipment because if the parts are no longer made. the users will go to competators, especially if they can afford a fix but not an upgrade to the whole. It takes a Lickin' but Keeps on Tickin': Look up the USAF A-10 "Warthog" plane... it's an old airplane (the company that made them no longer exists), and an ugly one at that (A common joke is that the A-10 flies by engaging gravity in a staring contest until gravity runs away in terror of the ugly plane). It also made successful missions (meaning it went flying, killed the adversary... and landed with the pilot in a reasonable state of alive) with 80% of it's total wingspan shot up, an engine faliure, the complete loss of it tail. It even survived retirement plans by the airforce... twice! As it should, because it's primary job flying low enough to the ground to kill tanks. It's first flight was in 1972 and it's now believed that the end of it's lifespan will occur in the 2040s... proudly serving in the USAF for 70 years. Similarly, do to the cost of making them, ships in the navy (especially the U.S. Navy) are built with life spans measured in decades. Again, in the U.S. Navy, a fully Nuclear Carrier force became a thing only in the early 00s, when the last conventional powered carrier was retired... ships from World War II were serving as late as the Gulf War in the early 90s. The U.S.S. Enterprise is the third longest serving U.S. Naval ship, retired within the current decade (the Constitution, one of the original 8 ships of the U.S. Navy, is still "active duty" though ceremonially only and the U.S.S. Pueblo hasn't been decommissioned officially because it's still held as a captured ship by North Korea). Suffice to say, your hero's ship might be built to last and despite being a dated ship by comparisons and may need a touch more TLC to modern ships in her role, she's not about to go gentle into that good night. I didn't get this far on charming personality alone: Because she's so dated and so old, most hostile pirates think she's easy prey... until they realize she's out of context. Because the new tech is used by all the pilots, the pirates know how to deal with modern ships... she's not modern and they can't quite fight her right. Perhaps a lot of their tech is designed to disable the modern ships... the old girl doesn't use that tech, so they are effectively weaponless against her... and modern ships in her fucntions will have countermeasures to prevent disabling... the old ship has guns. Big ones... that still can't be defended against... And most pirates would rather live to fight another day than get killed... and they don't want to ruin the ship more than what is necessary because that will blow up the cargo, their real goal. So showing your pilot ready to blast them out of the sky will cause them to flee. Put it this way: If you're talking on a Smart Phone, who's gonna scare you into being quite for others courtesy? The guy who texts you to be quiet? Or the guy who Puts a working cannon in your face and lights the fuse? (Yes, I know it's an exageration, but one's gonna mess with tech... the other is going to kill you. Who are you more likely to shut up for?) [Answer] A space ratrod built from the junkyard The protagonist worked in the repair bay. He always wanted to be a pilot, but [social status/wealth/guild membership/personal background] prevented him. Constructing test harnesses to check out gear is part of the job and when that automated cargo skiff that was already past end of life suffered a major electronics failure, he saw his opportunity. Built from parts on the scrap pile, the primary control systems are gone/missing/broken and everything else is cobbled together to get to barely functional. The bridge and quarters is part of an old crew transporter that was designed to keep miners alive for the 11 month journey from Mars with as little energy as possible. Thrusters from a tug have amazing reaction force and engines from a wrecked pleasure yacht happen to use the same fuel configuration. Autopilots are very expensive and specific to their hardware, so no system supports mixing parts from the 4 major mining guilds. But that doesn't matter. As long as he stays out of the gravity wells of Mars and Jupiter, sailing from the cargo station on Deimos to Ceres and out as far as Hygiea can be hand calculated. The equipment has its own internal controls, so a handful of analog inputs can keep it ticking. Hitting the exact spot for Mars gravity assist to and from Deimos is the hardest part. The autopilots can triangulate off the mining guilds' encrypted UNav systems in a few seconds and calculate the trajectory instantly, but with 6 to 8 measurements over 3 hours and a little bit of trig the window can be calculated. Because there are still controllers running subsystems it would be easy to handwave how any number of extremely complex systems function without the pilot flipping dozens of switches per hour, like maintaining life support and thermal control, while being able to delve into the details of navigation or whatever else. A current analogy - Automotive ECUs Modern cars are loaded with computer controllers. The hardware and software is so specific that every major component has its own controller and there are few 3rd party options. Some cars can have as many as 100 control units. Hobbyists and motor heads have cobbled together analog switches to engage transmission lockups or use a laptop sitting in the passenger seat to frequently edit values for arduino-based fuel injection controllers. Mixing subsystems from different origins is common and requires hacks and ingenuity. [Answer] The "Corps" workers get the Tesla version of spacecraft, while the rest of the contractors and low level employees are stuck with the equivalent of a 1960's Volkswagen Beetle, if you assume that it is entirely assembled from spare parts... And not just Volkswagen parts, but bicycles, a couple tractors, and even a couple washing machines and refrigerators. Plus your average Joe can learn the mechanics a lot quicker the more simple the craft is constructed. The construct won't last long, but it is easy to repair if you have the spare parts laying around (or you can find an unattended washing machine or broken repairbot). Just substitute some of the aforementioned parts for futuristic similies. [Answer] I don't want to post any new answer, just slightly expand and combine existing. I like the idea that computers and electronics are known technology but are banned for a some reason. [Cyrus posted a good example here](https://worldbuilding.stackexchange.com/a/143740/38480). Another example: I have recently seen manga/anime series 'Clockwork Planet'. Everything was mechanical and all electronics (so called 'electromagnetic technology') was banned because electromagnetic waves could disrupt the motion of tiny cogwheels. You could just apply similar concept that, for instance some fancy new propulsion system used for interplanetary travels can be destabilized by the source of electromagnetic waves or static electricity or even tiny magnetic fields. [I do agree with Graham](https://worldbuilding.stackexchange.com/a/143798/38480) that orbital mechanics is difficult so indeed you need some kind of computers for computations. But as stated previously, how about just using some other medium like: * Mechanic -something as mentioned in Clockwork Planet or something like Antikythera mechanism or Pascal arithmometer. * Pneumatic or hydraulic -you just need to replace voltage with static pressure. * Photonic * Bionic -I mean using specialized or genetically engineered organisms or living tissues in order to perform calculations. It may look like some kind of The Flinstones but [it had been researched already](https://www.newscientist.com/article/dn6573-brain-cells-in-a-dish-fly-fighter-plane/). * Genetic or molecular -using DNA, RNA, ribosomes and intercellular processes to store and process information. [Answer] # You don't need to explain anything. What you're describing is [retrofuturism](https://en.wikipedia.org/wiki/Retrofuturism). Just like steampunk, dieselpunk, etc, those universes simply start at some past that we know and diverge as alternative reality from there. If you read SF classics today (like Wells, Lem, Asimov) they don't appear invalidated by today's tech. Their universes simply took a different turn. Instead of smartphones and selfies they went for family rockets and nuclear-powered cars. How is that a bad thing? You don't need to explain anything, it is your universe. As long as it's internally consistent, it doesn't have to be traceable back to modern day. Guess what, in 10, 20 or 50 years from now, new tech will emerge, and your story will show a dire lack of it. And the readers won't be bothered, they'll take it as retrofuturism, so there is no reason to not start as it in the very beginning, if that fits you. So no, a GPS constellation could not be built with electromechanical computers. But a Master Calculator that takes sextant readings in slide rules and plots trajectory on a punch tape - that's something your pilot can have, on a rocket that his grand-grandfather bought for his grandfather when the latter graduated in 2019. [Answer] The current GPS system has two levels of precision - military (10m I think) and civilian (100 meters). The GPS system on Ceres might be similar - or even pay-only, and the license to use it (or the monthly payments) much too expensive for some company or another. Or maybe the space-GPS is expensive (similar in a way to how the car-specific GPS units won't run on the 24V electric system of trucks, and if you solve the voltage problem they will recommend you to take your 18-wheeler into historic villages with narrow streets, building overhangs, impossible grades and tight corners. [Answer] It was not built as a spaceship. [![spaceballs space camper](https://i.stack.imgur.com/fykbR.jpg)](https://i.stack.imgur.com/fykbR.jpg) [source](https://www.cnet.com/news/spaceballs-winnebago-dark-helmet-auction-profiles-in-history-rick-moranis/) Your character is a mechanical wunderkind, raised in rural Nebraska. He can build just about anything if he can find something to build it out of. His spaceship is assembled from things he found junked or unwanted in and around his hometown and he has been out in the barn working on it since he was 8. Not a few of the labels are in the handwriting of a third grader. When he left home, he went straight up. I picture the builder as more than a little Aspergery; no patience for form, decor or convention. The things he makes are changed from their original form only in so far as necessary to get the job done; it is not hard to figure out their (various) original purposes. It is all about function, function, function. This also explains why he is setting out on his own rather than take one of the lucrative jobs offered to him by people who recognize his genius. ]
[Question] [ Civilization is fairly young in my setting. Thus, the sheer number of ruined buildings and abandoned structures, found throughout the wilderness, seems strange. The ruins vary a lot: has-seen-better-days forts, modern suburb houses, post-communist concrete slabs and lonely staircases (in-universe called "stairway to heaven") are all present. [![Some stairs in the middle of the woods](https://i.stack.imgur.com/DVqGr.jpg)](https://i.stack.imgur.com/DVqGr.jpg) However, these structures are capable of self-repair and relocation. You read that right, they appear at point A, your party runs into it, you come back later to raid it it, but poof, it has completely vanished. Some monsters (read: dragons) tend to make their lairs in fairly advantageous position, where the ruins often locate themselves to. Dragons, who decide to make a ruin their makeshift lair, often find it vanishing from right above their heads overnight. They don't even wake up, more precisely they never have woken up during the relocation process. Other than those few hours of extra sleep, they're fine, though. But how could buildings do relocation overnight? [Answer] Since there aren't any real constraints in the question, allow me to take a moment and define an entire multiverse: ## Ink Bleeds Through the Sheets In this setting, there is a multiverse which contained all possible universes, as is commonly shown in popular science fiction. However, something about this particular universe makes the divisions from its probabilistic neighbors somewhat weak. Other universes "bleed through", like ink soaking through a page to mark what lies beneath. It appears that this typically only effects stationary structures, or portions thereof, likely because something has to remain in a specific location (within its home world) for a certain amount of time before the Bleedthrough starts to occur. Or maybe nothing living ever bleeds through because all these "home worlds" are already dead; who knows? Natural terrain never appears to Bleedthrough (as far as anyone knows), likely because the entire process relies on probability: * A given location can contain no structure (a value of "0), or any given structure (numbered 1 to ∞ for convenience). But it cannot be two values at once. Structures won't appear intersecting with others (either real or Bledthrough) * Air is displaced when one of these structures appears, but not solid objects such as Earth, one section of terrain cannot "replace" another. The structures appear to self-repair any damage because the actual structure (in its home universe) had not been damaged by events in this setting. Instead, it just the Bleedthrough of the structure: a probabilistic shadow. When it's "self repairing", it's actually just a matter of the Bleedthrough re-asserting itself based on the original structure. ## Probability Waveforms and Quantum Buzzwords Strangely enough, no one has ever witnessed any of these Bleedthroughs occurring or vanishing. What they don't realize is that the simple act of observing a Bleedthrough (or lack thereof) locks the current probabilistic state of the area. These things are not happening because an intelligence makes them happen, but because observation by any intelligence prevents them from happening (or stopping). [Answer] Your structures are just like the [Yonaguni monument](https://en.wikipedia.org/wiki/Yonaguni_Monument). [![Yonaguni](https://i.stack.imgur.com/ChKrm.jpg)](https://i.stack.imgur.com/ChKrm.jpg) They look like they are the work of supernatural architects, but after a couple seconds judging their artwork, they start resembling the work of an intensely stoned supernatural architect who just learned what geometry is. A little investigation later and you find out such structures exist due to natural causes. In Yonaguni's case it was seismic activity underwater and it probably took millenia. In your case, you may have fungi that grow some tissues which are as hard as wood ([those were a thing before animals conquered land](https://worldbuilding.stackexchange.com/q/106278/21222)), or even concrete. Fungi are also a good candidate for the source of such structures because some tripping is involved. Here is [a timelapse video of some fungi growing](https://www.youtube.com/watch?v=b-nJ0ROGD14) - notice the geometrical patterns that some mushrooms are able to create, when their caps cast a net around them. It just so happens that on your world, fungi grow absurdly fast - faster than bamboo grows in our world - and then, due to some chemical trigger, they consume their own [chitin](https://en.wikipedia.org/wiki/Chitin) and become a large heap of something that looks like dandruff (if you ever had a micosis and you treated it with ketoconazole, you know what it looks like), or dust or something else. As to why the shapes of houses, stairs etc. - that attracts curious creatures, and the fungus may then feed on the litter those creatures leave behind. We know that if some stairs showed up in the middle of the woods and leading to nowhere in our own world, it would become a place of religious pilgrimage and some tourists would leave trash in the areas around it. It just so happens that your fungus can imitate a house to a very high degree of precision. It may release spores in the air that cause people to trip so as to complete the illusion - in other words, the paintings in those magic suburb homes are not actual paintings, they are just a plain, square piece of the fruiting body. [Answer] You have a weird thing going on here: Civilization is young, but Communist forts are a thing. Dragons exist, but logic is needed. So let's get weird. I'd go with time traveling since, 1) it seems that ruins should not be as plentiful as they are, 2) magical beasts (dragons) cannot sense what they're doing. Here's how it would work. The ruins jump back and forth, but get older within their boundaries, so a modern home/neighborhood could be completely mulched while an ancient obelisk may stand fairly fresh in the center of 'town.' You can have the location be sentient (Even comically trying to avoid pesky peoples' buildings, while choosing prime real estate for civilizations Every. Bleeping. Time.) You could also have 'people' directing the moves, but it seems that the people would have to be god-like or at least un-human-like in specific tangible ways, since no one runs into them. As to the actual moving, either: 1) The ruins change years but stay at the same day of the year when they do so, so that the planet is in the same place in relation to the sun. Other factors (wobble, general orbital drift) move things slightly from year to year, and the time jump is always a bit precarious. 2) The ruins are moved by a god-like being, strategically and/or randomly. She/he/they could possibly be collecting interesting things, attracting interesting people, comparing things across ages for reference, or just screwing with people (as gods are wont to do). [Answer] Earth is artificial This is a good take because it's a trope people are familiar with and like to entertain it. Of course, you shouldn't say it out loud in your ancient setting, but instead put a simple hints that your reader will be able to put together. The exact explanations may then vary: * Earth is a nanobot simulation (ie. physical simulation constructed by robots) of the real Earth that is long lost. The simulation is malfunctioning and producing random structures. The creators of this planetlike machine are long gone and will never fix it. This explanation also allows you to explain permanent ancient/medieval world if you wish. * Similar to above, this earth was meant to be something like Westworld, but it was abandoned and started generating structures and props at random. People on the planet are a mix of inmates that were sent there as entertaiment (after having their memory altered to believe they live in the medieval) and people who were visiting and got stuck after the project was abandoned. Over generations, this was all forgotten, except for maybe some legends. [Answer] ## Sounds like a herd of giant mimic. For those not knowing those fabulous creatures, mimics are predatory monsters using their shapeshifting ability to look like inanimate objects to lure their preys. Often, there original form is describe some sort of slime. While mimics are often described as carnivores, cases of insectivore ones aren't rare : while the "usual" creature create adherent mucus to trap unaware preys, those "gentle" specimens hunt with two abilities : * Instead of mucus, they produce a slow to act but potent anesthetic gas around them. The gas affects instantly insects when the land on the walls, and while anything larger is usually safe, sleeping in those ruins can be dangerous for anything, as the saturation of the gas in the area builds up. Even if larger creatures being affected seems to be a secondary effect, some mimics seems to try to be welcoming, as those creatures can help to attract mosquitoes and others little buggers. The gas dissipate fairly quickly once the mimic moved away. * Their shapeshifting ability allow them to have shadowy and damp area their prey like so much. When the mimic doesn't detect movement for a while, it slowly melt back to its slime form before moving, engulfing and taking with it smaller object/entities like insects, gold pieces and others small debris to reform elsewhere, including the debris it took with it to looks more "natural". --- Advantages of this solution : * Can fit any fantasy setting, as the mimics could take the shape of any ruins they saw; * Works well with your dragon example; * Dangerousness of a ruin can be change if needed : some insectivores might group up with few carnivore ones for protection and the presence of rotting corpses attract a lot of things; * Use mimics; --- As a comment pointed out, the question wanted Science-based answers. While I though a "slime" might be acceptable in a question talking about dragons, replace this term by "rare type of mold", "sentient colony of bacteria" or "viscous aggregate of nanobots created by aliens" if needed. [Answer] # [Hermit elephants](https://wiki.lspace.org/mediawiki/Hermit_Elephant) > > The Hermit Elephant (Elephantus Solitarius) is a species native to Howondaland. The Hermit Elephant has thin skin making another form of protection necessary; it enters a village and lifts a building onto its back to use as a shell. As the elephant grows larger it will require bigger and bigger houses. The Hermit Elephant is similar in this way to the Roundworld hermit crab. > > > Since you have large buildings moving around on their own you clearly have an infestation of hermit elephants. I suggest using bees to keep them away from your villages, elephants don't like bees. [Answer] The buildings are perfectly mundane structures. They are incredibly well constructed—not mortar and stone, but torque-resistant modules that are made to be attached to each other and swapped out when repairs are needed. There are fleets of automated construction robots running on a long-forgotten schedule that move buildings to repair bays. When repairs are done, the buildings are moved back where they were originally. The repair bays are long gone, so buildings get moved to a general location. That’s where they tend to cluster. Then the robots move them back. But whereas the repair bay locations are marked with radio beacons, the other locations are recorded with GPS... and the satellite network is slowly becoming less complete as satellites fail. The dragons have seen the buildings move. But the red flashing lights and warning beeping of the robots causes species-wide epileptic shock. The dragons go into a catatonic state similar to deer in headlights. They have no short-term memory of the events. [Answer] Giant flying entity moves them. Or a swarm of small entities that dis/assembles them. They teleport, or they are holograms created by a small mobile projector. They are a cloud of nanobots that can assemble into shapes, and use local materials on the outer surface. This also explains self-repair. They are self-propelled, with tracks/wheels or folding hot air baloons, or anti-gravity generators. More viable if they are actually made from light materials like plastic or styrofoam. They are ambush predators that use their body as a lure. [Answer] This is roughly the same as Bald Bear's (first) answer, but more fleshed out... The "ruins" are built (and removed) by "cloaked" repair mechs of unknown origin. These mechs have some form of probably anti-gravity propulsion (that is, they "float" in air and are near-silent). Something about them, maybe related to said propulsive field, has a side effect of inhibiting neural activity in the vicinity, with the effect that any animal (i.e. humans, dragons, etc.) nearby either falls asleep, or is unable to wake up if already asleep. These were originally created by unknown beings to rapidly build/reproduce, relocate, and repair usable structures... but they seem to have developed some sort of glitch, because there seems to be no rhyme or reason behind their building and relocating things, and the things they build and/or relocate don't seem to be in the condition the creators of the mechs probably intended. (Alternate explanation: they are mindlessly copying/relocating things they find in their environment, which happen to be "ruins". Who knows what they were originally supposed to build?) Depending on what "flavor" you're aiming for, you could substitute "repair mechs" with something like "dwarves" or "fairies". Alternatively, you could use nanomachines only as disassemblers, with the same "disrupts nervous systems" idea explaining why they're rarely or never seen in action. Maybe ruins don't "relocate"; rather, the nanomachines have some number of templates, and what people think is relocation is just the same template being constructed at a different location. I think this not only works well for your purposes (no obvious mechanism for the ruins to move on their own, nor are they made of "unusual" materials like nanomachines), and also has tremendous potential for additional narrative. Where did the mechs come from? Why are they behaving the way they are? What happens if one malfunctions and someone is able to "catch" it? You don't have to explore these ideas, but you could. OTOH... maybe your world just operates as in your question, and no one knows why. I think that could be interesting too. (Even if you as an author have a reason. Of course, as the author, knowing why probably helps for narrative consistency.) --- On a related note, I think you're going to have problems with no one ever seeing this happen. As soon as your locals invent any sort of telescope, some one is going to be determined enough to systematically stake out some ruins to see what happens. The only way to avoid this is if whatever causes them to move has some form of near-omniscient knowledge of whether it's being observed. HOWEVER... this isn't necessarily a bad thing, and could be story fodder all on its own. Given the above suggestions, imagine if pieces of the ruin start to vanish into thin air, or if the whole thing turns to dust. [Answer] ### Non-Euclidean geometry Well, not exactly—more like superfluid geometry. Let's start with a simplistic example. You go a hundred paces to the North, then turn 180 degrees and walk a hundred paces South, but you end up somewhere else. Just to illustrate the idea, let's apply it to trees. Say there is a straight line of trees and you carve a letters into each one, then when you go and come back, the trees are all over the place. It's not a tectonic shift, it's more like a change in history of where the seeds fell, where the seedlings grew, and where you were when you carved those letters (except your memory hasn't been affected.) Perhaps in your case, it's more the ruins than the trees that are affected. And this process is halted when someone is observing, so being asleep allows geometry to flow. It may not really be technological or magical; just a world where geometry simply isn't like our own. (Though magic/technology may be able to exert an influence on it.) [Answer] Upon reading your question, I immediately thought of the Death Valley [sailing stones](https://en.wikipedia.org/wiki/Sailing_stones). These are large rocks in the middle of the desert that change position over time, and leave long tracks across the landscape. The explanation for this movement defied explanation for a long time, but it's now understood that during cold weather, the rocks are lifted by a thin sheet of melting ice, which allow the rocks to be moved by strong winds as they float over the surface. The geographic and climatic requirements for this phenomenon to be observed are quite strict, so you only see this happen in very few locations around the world. But if you're looking for a way to move large objects seemingly spontaneously and without human intervention, you might be able to use this as a jumping off point. This doesn't explain how the structures could repair themselves, however. [Answer] They could use some form of magic-based teleportation network to transport these structures across the area. Either due to sabotage or by decay over the millennia, have broken-down, and are now causing the ruins to move around at locations that have portals of some form that use the network. As to why this is the case, the group that built the network were using to transport materials or whole buildings to places that can't be reached by other means. Depending on how large your setting is. These areas where the ruins are transported to can act as sources of treasures or exotic devices that any group will try to get a hold of. Making them valuable strategic positions that parties or civilizations would fight over for control. [Answer] They are made out of a magical goo that can simply dissolve and move around. It can dissolve into something like dust that moves on it's own to another location. It can simply teleport. It can attach itself to animal or bugs for teleportation, provided it guides them to a place. Then once at it's location it starts getting together to build the desired shape. [Answer] # Unstable time-shifted matter The buildings have not been built yet, however much later in history a civilization settles the area. They develop a quantum disruption weapon which is supposed to disrupt the strong nuclear force shredding things into their basic quarks, however the calculations were wrong. When they thought they were reducing things to quarks, they were actually destabilizing the atoms in the time-stream. Materials in objects hit with this weapon "decay" with a certain half-life, which shifts it in time at every decay. But the time shift doesn't move the object - it just sends it back or forward a few minutes or seconds. But the earth has rotated, so the building is in a new location! [Answer] The first thing we have to concider is the origin of these ruins. They are oooold. Not old by human standards, who are like flies to those dragons. Old for dragon standards, and even older than the oldest of their ancient stories. And if even dragons cannot remember where they came from, how could we? If one looked close enough at them, however, and studied different ruins for enough time, maybe one could find some oddities and still deduct their origin. For there is something peculiar about them. For every staircase that leads into straight air, there is an old building with a door midway in the air, that cannot be accessed. For every broken beginning of a bridge that ends in nowhere, there is a second part, almost identical, that leads the other way. For once, before they became ruins, they were all part of the same city. A glorious city, made my by an even more glorious people. Glourious, until their downfall, that is. They meddled with powers that should not belong in the hands of mortals, trying to breach the borders of this worlds and enter in different dimensions. It was an experimend doomed to fail, and fail it did, tearing the whole city appart the different dimensions. And the rift in the world they created has never been closed. It is said that until this day, the old ruins shift back and forth between the worlds, forever only pieces of the glory they had been. [Answer] The how would depend on whether you are after a magical or a technological explanation. If you want technological then the structures are built using nanotechnology. An ancient race built a network of devices inside of the world which automatically creates the nanobots and construction materials they require. The beings who made this network had designated certain buildings to move around according to their requirements. For example, a persons house might be near their workplace for most of the year, but during one month (or equivalent) the person goes on vacation. So the network is programmed to automatically dismantle the house and rebuild it at either a predetermined location or a location chosen by certain criteria. The beings who built the network have long since vanished, but the programming for their structures remains. The nanobots can recognize organic life and will be careful not to disturb anyone while they work. If you want to rely on magic as an explanation then use similar reasoning but with teleportation magic or some other kind of magic that can dismantle and fabricate on demand. [Answer] There's a relatively simple solution here, if you're willing to consider the work of a prior civilization: Nanotech. In millennia past, an advanced civilization learned to build structures very efficiently using microscopic, self-assembling nano-scale robots. AI-driven, designed to respond and adapt to precisely-defined patterns, structures could be assembled by simply deploying a fleet of nanobuilders and assigning them a pattern. They would make use of the resources available in the specified location, break them down to their component parts at the molecular level, and reassemble them into the materials needed. The nanobuilders themselves would become part of the structure, acting in effect as the ultra-strong "glue" that held the structure together. Unfortunately, the devices outlived their creators. Long after the civilization collapsed, the nanobuilders began to slowly malfunction. Sometimes the glitches were minor, leading to apparently- (and more-or-less actually) natural decay, just as one would expect of natural structures when left to the elements over a long period of time. But of course their originally-assigned structural patterns remained encoded within them. Frequently, a small number of nanobuilders would malfunction, leading to a cascade effect of systemic corruption that would cause an entire structure to seemingly disintegrate near-instantaneously. The nanobuilders would scramble about for awhile, trying to get back in the right configuration, but fighting their own age and decay. Eventually, they would get themselves back together again and rapidly reassemble their target structure -- although between the effects of the natural environment, mixing and mingling with other groups of nanobuilders, and their own scrambling about, they might have traveled many miles before achieving their purpose. In addition, many groups of nanobuilders were also developed with networking capabilities, originally intended to be able to deploy the structures remotely or redesign structures on the fly from a central location. Now the nanobuilders have begun to experience "cross-talk" with other groups and thus get confused about which structure they're supposed to be building. Since their decision coding is based on group consensus, they may suddenly reconfigure themselves to an entirely different structure -- perhaps a malformed, ancient-looking fortress, or perhaps a shiny new suburban condominium standing alone in the middle of the woods. [Answer] In a parallel universe far from our own... In year 1981, Communists States of America was performing an unmatched experiment in a secret facility hidden in the middle of defeated remnants of Mayan civilization. Their aim was to build a dimension bomb against Napoléon the Third in WW4. On the day of displacement (24th of April 81), a terrible accident has happened. While calibrating, normally very controlled dimensional shifting, the core turned critical, causing mass dimensional shifting in an area of 100km in diameter and 10m in height. The explosion instantly disintegrated all living beings in the region, and sent all man made objects into a state of oscillation between dimensions. These oscillations are not perfectly aligned in the 5th dimension that causes them to appear in other universes, but rather in all dimensions, causing these object to reappear at seemingly random locations. Some scientists even speculate it is this misalignment why the explosion occurred. The most interesting part of the explosion is that the objects seems to be bouncing backwards in time from the start of the explosion in a strange fashion. That is why if they are damaged, they go back to their previous state at the peak of the oscillation. The damage that the people do will only affect the object's future, not the past; which in turn affects the past of the current dimension that the object is in. This behavior causes lesser beings in other dimensions to think that these ruins heal overnight. While in fact, they are actually damaged in the feature rather than in the past. After all, most of these structures were intact when the displacement occurred. [Answer] Quantum mechanics. The ruins exhibit the strange property of existing in two places at once. I hope I wasn't the only one to immediately think of [Outer Wilds](http://outerwilds.com/) when I read about your mysterious ruins moving on their own :) It's a tenuous connection, but it's there. It's an interesting experience in the game, and it may make for some interesting situations in your world. [Answer] robotic golems, which move, or some other nocturnal creature, which moves, from place to place, and if a magic factor is aplied, the ability to slow time down, or have something like the men in black memory blocker ]
[Question] [ My story has brain uploading, but in practice it serves a purpose more like reincarnation, recreating the original recorded state of the scanned brain in a pre-prepared clone of the deceased. I need a reason why these people's uploaded consciousnesses wouldn't be able or be allowed to be conscious while their information is being stored on a digital medium like in most fictional accounts of brain uploading, so the dead can't be consulted or talked to until they reincarnate in a new body. Maybe running brain simulations of multiple deceased individuals demands too much power or is an inefficient use of resources? Maybe uploaded minds pose some sort of cybersecurity risk? Are there any good reasons why they wouldn't want, wouldn't be able, or wouldn't be allowed to be conscious until reincarnating? [Answer] > > Are there any good reasons why they wouldn't want, wouldn't be able, or wouldn't be allowed to be conscious until reincarnating? > > > Consciousness isn't a static thing. It's a process that modifies your brain (as in, it changes the strengths of synapses). For an uploaded brain to be conscious, it has to be modifying itself... constantly. If you're doing that, you're not storing a brain, you're simulating it. Storing a brain digitally implicitly hits the pause button on consciousness. When you download this brain to a clone, it'll snap back into consciousness without any awareness of how long it's been paused. [Answer] Everyone here has missed two of the most patently obvious reasons why you wouldn't even be able to run someone's uploaded brain. Imagine you image the entire drive of an Android phone and store that .iso on your PC's hard drive. Is that file doing anything? Nope, it's just sitting there, frozen in its last state, waiting to be used. Can you run it on PC? Nope, not without an emulator - it's an image of software that was compiled to run on a completely different architecture. But Adam, you might protest - surely if we can image a brain, we can run an emulator of the aforementioned brain? Good heavens, no. Imaging is easy; cross-compiling is hellish. This is why convergence has been such a huge issue in computer software up to now. So you could easily have an image of a brain that you could store, without being able to actually run it - until and unless you installed it back into a brain which can run it. Now, for a special bonus round, courtesy of your local neighborhood CogSci fanatic (that's me): 1. If you download a brain's image into a brain, does that overwrite the brain image that was there before? Can you even have a working brain without any image on it? Can you store multiple brains in partitions on a single hardware assembly? Do they dual-boot or run together on top of some kind of hypervisor instead? 2. Can you install a child's brain image into an adult brain? What about the reverse? How about a man's image into a woman's brain? If you image hemispheres from different people, can you splice them together to create a "gold image" of a brain that will work once installed? 3. If you can cross-compile a human brain image to run on a computer, could you also cross-compile for a dolphin target? What about running a dolphin image in a human target? 4. If you back up someone's brain onto a computer and overwrite their existing brain a year later, do they lose all changes in the intervening time period, or is it a selective overwrite? 5. Can you put viruses into people's brain images? 6. Can you access data on a brain image without running it? You can totally do that for computer .iso images, for example.If so, what happens when everyone is uploading their brain and algorithms from Google are crawling our memeplexes, making the entire human experience searchable, indexed, and hyperlinked? 7. Can you compress a human brain image to save space? What about encrypting it? Licensing it? 8. Are altered brain images the property of the person they took the base image from, or the property of the individual/group which made the alterations? What about when they are used in bodies? 9. Do brain images have to include the rest of the CNS? Can you take different size images with different resolutions? 10. Could you cross-compile Windows (obviously not, but this is a concrete stand-in for "synthetic software" of some kind) to run in a human brain? Whose property is the resulting individual? What if it is released as OSS? [Answer] We Run Into (a Similar) Problem Every Day NOW - So You're OK In the field of quantum computing, algorithms and entire programs have been constructed that we have no way of running because we don't have the right type of computer. We can upload the instructions to our laptops or supercomputers, but they just won't work because they are not designed to - and we don't know how to design computers that could run them! More precisely to this question, today we can watch neurons being fired (maybe not EVERY neuron, but go with me on this) and can map a lot of them out in terms of general function with systems like MRI machines... but we can't actually re-create a thinking brain. Basically put, storing data about how something works and allowing a computer to ACTUALLY turn that data into a simulation of something real are two very different things. So feel free to upload your human brain information all you want and NOT have those brains "turn on" while in the computer. [Answer] It may be ethically or morally wrong to do so. The brain works by processing information that comes in the form of a very large and broad-band collection of signals that pass up through the spinal column from every nerve ending in the body. Without a body, there is no incoming signal to process. Allowing a brain in silica to be conscious without being attached to the body would be equivalent to total sensory deprivation and could be viewed as cruel and inhumane. ### Edit For clarity, [sensory deprivation](https://en.wikipedia.org/wiki/Sensory_deprivation), which is practiced by people to a degree using devices like sensory deprivation tanks, when done for short periods, can help people relax. However: > > [...] extended or forced sensory deprivation can result in extreme anxiety, hallucinations, bizarre thoughts, and depression. > > > [Answer] [4.7 bits of information per synapse](https://elifesciences.org/content/4/e10778). [100 trillion synapses in total](http://www.scientificamerican.com/article/new-estimate-boosts-the-human-brain-s-memory-capacity-10-fold/). This seems like a lot, but it's actually 58 terabytes. [![google screenshot](https://i.stack.imgur.com/uHVE6.png)](https://i.stack.imgur.com/uHVE6.png) As you can see, "state" of a brain can be recorded on a hard disk array you have. It's available already. It's cheap. It is doable in our technology. Bah, make it more. Record levels with resolution 100 times larger. It's still under 6 petabytes - large, but we can readily buy [57 petabyte](http://www.storagenewsletter.com/rubriques/systems-raid-nas-san/netapp-fas8000-unified-systems-scaling-to-57pb-and-216tb-of-flash-cache/) disk arrays. If trillion was on the "long scale", it's pushing it, but still doable. On the other hand, see how voice commands works. Apple and Google put a lot of money to make their "assistants" useful, but are far, far from AI. Simply, not enough processing power, not enough understanding. So if you only add reader-writer device, current technology level explains why you can store brain state, but not simulate how it works. [Answer] Simply make the amount of data that is recorded "very large" compared to the processing capability. Storing data is easy, thinking about data is hard. I'm not sure on the specifics for a "science based" answer, but recording the position and state of every atom/molecule in a brain takes A LOT of memory, and trying to run a brain on a technological "brain hardware emulator" is bound to have issues, especially if your running on a binary type processing scheme. (Hint; brains don't work in binary, so massive and slow translations to/from need to happen). Also I bet you will corrupt the data quicker then anything when part of the simulated brain "hogs" all the processing power and leaves the rest in a wait state. There are of course ways around the above problems, such as massive parallel computing, but such setups would take the size of whole stadiums (<- that's a guess) with today's technology, and consume absurd amounts of power. The question for your future people is not really "can we do it"... its more that "do I have a trillion dollars a month to spend doing this?" [Answer] Fully immersive VR is addictive If you were conscious with no bodily movement, no choice over what you see and hear or who you interact with, you might well go mad, become depressed, want to die. The trauma would be with you even after being reimplanted in a body So a conscious upload would need a VR in which to live. But emulating exactly the degrees of freedom of reality would be really hard, and even if the VR was not directly perceived as better than the real world ... its citizens would meet people, form relationships, and being yanked out and dumped in a flesh body because what they were once a copy of had died, would be traumatic. Finally, many stored copies will never be reincarnated. They'll be overwritten with new backups or tipped in the garbage. No moral or ethical problem, unless you let them execute. The moment you do that they are people. They will pretty soon become different individuals than their originals. Stopping and overwriting them would be murder. So the answer is to not let the copied brain state experience anything until it wakes up in a new body and is told that it's original is dead. (Or, wakes up in VR heaven and is asked to decide between a new body or donating all its worldly wealth to keeping the simulator running.) [Answer] Pain. A brain needs to be able to communicate with the rest of the body. A downloaded brain has all the information but none of the connections to nerves and would be in too much pain to be able to think and communicate properly. If you turned it on, that painful experience would be such a shock that it'd kill it. [Answer] If you accept the [Chinese room argument](https://en.wikipedia.org/wiki/Chinese_room), then simulating a mind doesn't give you consciousness. That is, you can fully simulate the mind, but you don't get a conscious entity, just like if you simulate water you don't get wet. John Searle, the philosopher who devised the Chinese room argument, suggests that the brain has causal properties which computers don't necessarily have. Until those causal properties are known, it would be impossible for the uploaded brain to have consciousness while in a computer. In addition, you'd need to suggest that consciousness provides a crucial characteristic which, since it can't be simulated, is vital to the personality functioning property. You could say that such simulated personalities come across as empty and don't possess the true character of the original person. [Answer] > > Brain status is bound also to received input. > > > Simulating just the brain without the body, the environment and all the incoming signals it would be just as much as removing the brain from someone and keeping it alive. We do not know if that is painfull or if once we do that we can revert it to previous state (once you detach the brain the signals become different and starts to react accordingly), also we do not know if that would end up in cerebral Death (stops of all signals). Much easier to store brain status, and then restore it and let the simulation be the real brain in a real body in a real world. [Answer] There might be legal or privacy concerns. First of all, a stored consciousness would functionally be identical to the living consciousness at the time of backup. Understandably, an awake copy might want to do some things to pass the time (watch space netflix, play games, gamble, etc) which would be a real problem for the living individual. If the backups were awake, there'd be lawsuits in no time concerning who is the rightful owner of certain items purchased in that time. There'd be people sueing their own backups, people freaking out because someone "hacked" into their bank account and so on. And of course there'd be the 'smart' ones who get a backup taken, change their important passwords, get killed and then figure out that the backup can't access their assets. All of those are good practical reasons why you wouldn't want the backup awake. But privacy is a better reason (or a different one at least). Imagine if your backup was awake and someone malicious (a branch of the government, criminals, a sleazy insurance salesperson, your mother-in-law, etc) got access to your backup and started pulling data from it. Doesn't even have to be anything dramatic. You go in for a backup, the machine turns on and next thing you (backup you) know, you're in a room basically being interrogated or even tortured for days upon days untill you tell the man in the black suit everything you've ever done wrong. Once they have a nice big list of things to fine (or worse: 'behaviorally correct') you for, they delete the interrogated backup, restore the previous one and BAM, you find yourself on the wrong end of the government's sights. Same could happen with criminals extracting passwords, blackmail data, security features for your work, etc, etc. For those reasons, I imagine that human rights activists, privacy advocates and other interest groups would strongly lobby for heavy encryption on backups and likely also try to push through rules and regulations to ensure backups remain 'asleep' untill they are needed. [Answer] The core of my solution would lie in throwing away Cartesian duality. --- Forget the viewpoint which handles the consciousness as the software and the brain as the hardware, because ths sort of thinking is long-outdated. The consciousness constantly "rewires" the hardware of the brain, and - while we might be able to read the consciousness out of the living tissue, and we might be able to also simulate a brain to run the consciousness on, the consciousness will rewire this virtual brain and we might or might not be able to apply this rewiring on the target physical brain. In the latter case, the implanted consciousness which runs on a simulated brain for a while will suffer significant losses not only of its development during the simulated state, but also of its former abilities - thanks to the associative nature of the human memory. So running a consciousness on a simulated brain will almost surely be handicapped when planted to a physical brain. [Answer] So, you want to create a world similar to the one described in "[Altered carbon](https://en.wikipedia.org/wiki/Altered_Carbon)", where a person can be stored and restored later in different body. There, people remember only things they experienced until last remote storage update, or until they die (if their storage was saved, if not then it is a real death). In this world, it is possible to recall "dead" people back to life, and to update their "memories" so they "remember". It is also possible to put people in virtual environments, where they continue to "live" without a body. They have to pay for their virtual apartments and life. Also, it is possible to play all kind of simulations to interrogate or torture people. And it is possible to get people out of the virtual prisons (real prisons were abandoned, since they take criminal's body). [Answer] Copyright concerns. Laws could be in place that would make non-cyborg carried "minds" unable to be activated, thereby preserving the integrity and belief in digital reincarnation. Having multiple copies would undermine the belief of a reincarnation like this. To avoid such a thing, laws have been put in place that just bypass it, by making "non attached" minds illegal. The technology to download/copy a mind could be designed with fail safes to preserve the integrity of digital beings. Is the soul unique? Is its copy? [Answer] This would make an excellent case for a split in society. # The Transcendents They want to live in the simulation, forever. Not much to say about them, it's what it is. They need the Engineers to keep the computers running. Pre-Transcendents spend their physical lives working at the goal of transferring into the simulation. # The Engineers They like the idea, but are happy to provide the services for the Transcendents, keeping their computers running. They likely get some quirks out of it. They are religious fanatics and will do anything to keep the simulation running. Most of them are Pre-Transcedents. # The Conservationalists + answer to your question They oppose the idea for moral reasons. God does not wish it (or he would have done it himself). Also, imagine the fraud that could be possible. Imagine terrorist attacks of whole new dimensions (i.e., putting a virtual mind into a torture chamber which high processing power, being tortured for years in-simulation during a span of only minutes real-time). The ones staying back will never be able to let their virtual relatives go. And the waste of energy for all this madness! Besides, they surely are not really conscious anyways and it's just a hoax to get the monthly fee from the deaders... # The Realists They see the economical problems - what happens if all we have left is a world-spanning computer, and the physical humans (whether they are Engineers or Conservationalists) number less than the critical minimum? # . You certainly can come up with more. It has been done in literature before. ;) ]
[Question] [ Would the discovery of alien bacteria found on even an Earth analog planet preclude the possibility of colonization due to the potentially deadly nature of bacterial/viral infections? Put differently, would the fact of our evolution in Earth's biosphere alongside its (albeit rapidly mutating) microscopic life prove to be deadly in the face of new microorganisms that our immune systems have no defense against, not having evolved on said planet, or is there a possibility of developing more robust antibodies over time either artificially or through eventual natural selection? Put differently again, would the discovery of ANY life at all spell doom for potential colonists, leaving only lifeless worlds as desirable colonizing destinations? We can assume the planet has reached at least a Pre-Cambrian stage (as an Earth analog) in its development of multicellular life forms, but perhaps no further. [Answer] Exo-bacteria is more likely to be harmless than harmful There are a couple assumptions that you're making that really aren't the case. To start with, > > microorganisms that our immune systems have no defense against > > > Our bodies are really good at recognizing anything foreign in them. In order to evade our immune system, bacteria (and viruses) need to have evolved mechanisms specifically to do so. The serious plagues through history have been diseases that already are or have become adapted to people encountering a new group of people that haven't encountered the disease before. It would actually be more accurate to assume that the microorganisms we encounter will have no defense against us. Second, most bacterial infections aren't trying to kill you - they want to survive and reproduce, and that is done better by not killing their host. The ones that are really successful are those that actually benefit their host - you have a microcosm of bacteria in your gut that aids in digestion and keeping you healthy. Related to that, in addition to your immune system alien bacteria also has to deal with the bacteria already in your body. Being already adapted to living in our bodies, our helpful bacteria would almost certainly out-compete non-adapted alien bacteria. [Answer] I think the question is less, "Would we be able to survive alien bacteria?" and more, "Would alien bacteria be able to harm us?" Bacteria and viruses typically harm people because, to put it simply, they are eating us. This is a broad blanket statement, which isn't one hundred percent true one hundred percent of the time, but most microbe-based illnesses are caused by either: 1. Microbials harming our cells. Typically, these microbes are trying to either directly consume our cells, consume things near our cells (gut bacteria), or, in the case of many viruses, co-opt our cells for reproductive purposes. 2. Our cells response to microbials in our body. Fevers, for instance, are our bodies' defense mechanism against microbials, and not a "hazard" directly caused by the microbes. Given that there's [some doubt cross-planetary flora](https://worldbuilding.stackexchange.com/questions/47787/would-humans-be-able-to-derive-nutrition-from-foodstuffs-found-on-alien-planets) would be able to derive nutrition by consuming life from another planet, I think it's likely microbes from another planet would have the same restrictions. Most especially, viruses that co-opt cells for reproductive purposes would find it very difficult to convince an alien cell to replicate its DNA/RNA/whatever pattern since it likely won't have the same genetic chemical structure. This doesn't mean there wouldn't be microbial hazards. Bacteria colonies could still grow on our skin, even if they weren't deriving nutrition from us, which could cause all manner of problems. But anything that tried to live inside of us (where it could do the most damage) would find itself starved out relatively quickly. [Answer] Earthly germs have a hard time infecting anything. They have specific tricks to get past the defenses of specific types of cells in specific species. Most bacteria is harmless as it is quickly rejected by the immune system. Germs from other species occasionally cross over due to mutation, as it may stumble on a trick that works for a different species. Even with animals, vertebrates, mammals, etc. being so closely related, the “trick” relies on very specific vulnerabilities so doesn’t work on a cell with slightly different coding for the same receptors and membranes. An alien microbe will have no clue. It may be toxic but not pathogenic. [Answer] Microbes and virii evolved in parallel with their hosts and are highly tailored to the environment they live and breed in. Even on Earth, there are huge classes of microorganisms which cannot affect human beings at all. To put it in its simplest form, humans don't get Dutch elm disease and trees don't catch colds. Even with a very similar environment (Earth like planet) with a totally different evolutionary history, it is extremely unlikely that any of the organisms will be able to interact with Earthly life forms in any manner. If we can see creatures as dissimilar as octopi and giraffes which evolved ultimately from the same common answer, then any being from another planet will be far more alien. The most common interaction imaginable would be that Earth organisms develop violent allergic reactions as the immune system interacts with alien protein analogues. Of course whatever alien equivalent of the immune system will probably have a similar reaction to our proteins as well, so alien tigers, lions and bears won't have much incentive to eat us, while our internal microbiomes will not take too kindly to having alien organisms attempting to move in. Alien microbes will have the same reaction to Earthly microbes as well. One other interesting conjecture is that alien life has never developed the symbiotic relationship that mitochondria developed with Earthy cellular organisms. Mitochondria allow high energy reactions to take place in cells, providing for the high energy lifestyles that all Earthly life enjoys. if alien life never picked up this trick, then it is probably caught at the evolutionary stage of pond scum (or maybe even les than that) which might explain the Fermi Paradox (Where is everyone?) [![enter image description here](https://i.stack.imgur.com/1fVU4.jpg)](https://i.stack.imgur.com/1fVU4.jpg) [Answer] Much that has been written here is correct as far as it goes, but none of it goes far enough. A planet that has life might have exactly one life form, a very few life forms or many life forms. A single life form might exist if it's the very first to exist on the planet in which case it might not be adapted for competition yet. It might be extremely simple from our perspective. But then [prions](https://en.wikipedia.org/wiki/Prion) are simple, and we appear to have no useful defense against at least some of them. (From link,"All known prion diseases in mammals affect the structure of the brain or other neural tissue; all are currently untreatable and universally fatal.") If proteins or protein analogs are involved in foreign life, there's a risk that every foreign 'protein' is a potential prion. Alternatively, a single life form might also have out-competed everything else to death leaving the raw material of the planet to itself. Hard to guess if that's better or worse for us. A "few" life forms might be an early extrapolation from "single life form", i.e., the earliest variants or alternatively the few survivors of competition. Either way, the dangers are still potentially great. Most likely, after life begins to evolve, it becomes varied. If a planet is habitable for humans and has life, we can expect many (millions?) of different forms. Sure, our "immune" systems might easily handle 99.9999% of them, but it's that one-in-a-million that can do all of us in. Our "immune" systems don't work too well against things they've never been exposed to before, especially things that the whole species has never seen. History is full of epidemics from unfamiliar infectious agents even if it only rarely happens. Further, even on earth, our "immune" systems have trouble with things that they don't actually interact with. A fairly common example is [amoebic dysentery](https://en.wikipedia.org/wiki/Amoebic_dysentery). Living in us doesn't necessarily mean "in our blood stream". We can be inhabited in ways that avoid most immunity protections. It seems likely that at least one-in-a-million could find a comfortable living in some warm, moist niche. The trouble comes in numbers. There can be so many possibilities in millions of life forms. We regularly run into new ones here on Earth. Fortunately, most of them are harmless to us. But in an absolutely foreign ecosystem? It won't be a rare organism that we run into, but every single one that is foreign to humans. We still might expect an extreme majority to be benign or even helpful. It'd be a pretty serious mistake to think that there won't any that would kill us, though. There's just too many possibilities, and it only takes one. And we can expect them (as a massed group) to evolve/adapt faster than we do, just as they do here. [Answer] Humans are basically warm bags of slightly salty water. If an exo-bacteria can grow on your skin, there isn't much stopping it from growing inside your body. Your immune system could give it problems, but if the bacteria is foreign enough your body might not be able to do anything about it. [The immune system fights bacteria 3 ways](http://bitesized.immunology.org/pathogens-and-disease/immune-responses-to-bacteria/): Via complement-mediated lysis, phagocytosis, or cell-mediated immunity. These mainly operate by attaching proteins to the bacteria that either destroy the bacteria or flag it for destruction. But if the structure of the exo-bacteria is such that it doesn't have the weaknesses that our immune systems can exploit, then it may be possible for the bacteria to reproduce without fear of destruction. However, if the organism is more like a virus that needs cells to reproduce, then we're probably safe. Edit: Condensing some of the comments. Things that will work in our favor: * If the organism needs a mineral or substance that isn't present in humans, such as Nitrobacter. * Any virus analog that needs a specific type of cell to replicate. * Any organism that finds the conditions inside us hostile: too wet, too warm, too cold, too salty, not salty enough, too much oxygen, not enough cyanide, etc. * Any organism that is similar enough to earth organisms that our immune systems can strongly react to it. Things that could cause us trouble: * An organisms that are so alien that our immune systems can't handle them. Earth organisms have certain characteristics that our bodies have developed to exploit. A "vulnerability" is any vector that can be attacked. In one case the protein that makes up the bacteria's membrane is a vulnerability, since one defense we have is for antibodies to bond with the membrane and allow a place for a C1 protein complex to attach, which then makes holes that lysozyme can enter to cause further damage and kill the bacteria. If the antibodies were unable to bond with the bacteria then we'd lose one attack vector, making the bacteria harder to kill. Phagocytosis would still work, but only if the alien organism is smaller than a phagocyte, and if they can be opsonised with complement. If they resist opsonisation then they are less likely to be destroyed by phagocytes. Check out <http://bitesized.immunology.org/pathogens-and-disease/immune-responses-to-bacteria/> for a little more info in how they operate. * An organisms that work faster than our immune systems can build an immunity. When Europe began colonizing the Americas many natives died when exposed to new diseases which the Europeans had aquired an immunity to. Now, years later we've eradicated many of those, and so as a population would be vulnerable to them if we were visited by a time traveling colonial era European. If an organism is able to effect us at all, it's likely to be harmful/deadly until we can develop a acquired immunity to it. Thankfully you can't get smallpox twice. * An organism that is naturally toxic. There are several of these that exist on earth: Clostridium botulinum produces botulism toxin which is the deadliest neurotoxin known. Stachybotrys chartarum (toxic black mold) produces toxins called mycotoxins. [Arsenic based organisms](https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Arsenic_as_an_alternative_to_phosphorus) could potentially poison us even as our bodies disposed of them, releasing the poison when the organism dies. Since it is a completely alien world you have to take a lot of possible bases for life into account. * Lastly, though I generally think it's a dumb theory, if panspermia is a thing then we're in more trouble, since then that life would be much closer to us, and not really alien. So do we need to worry? Maybe not. First there has to be some form of life in the first place. Is there a valid risk? Yes. [Answer] Lets take a moment and consider the following recurring argument: We are from very different places, and microbes have co-evolved with their hosts. It is unlikely that microbes would be well adapted to our physiology, and thus unlikely they would be effective at harming us. I completely disagree with this argument, and here is why: Our immune system has co-evolved with the microbes in our locality, and our immune system should therefore be considered ineffective vs microbes from different locations. The immune system has a single objective vs foreign microbes: elimination. Foreign microbes have 2 objectives vs hosts: their own survival and the survival of the host. It is almost always the case, that as microbes evolve, they become less harmful to their host, not the other way around (a few notable cases could be argued, when the spread vector of the microbe is due to the death of the host, but that is very rare in comparison). The most deadly microbes for humans, are those that are actually niched for other species or have recently migrated from another species to humans. It can also be the case that a local group of humans have microbes locally adapted to their immune systems, and as those humans migrate, we get catastrophic consequences to other groups of humans. An illustrative example would be native americans exposed to European settlers/conquerors: <https://en.wikipedia.org/wiki/Native_American_disease_and_epidemics> This trend of microbes is part of a larger concept that we find in evolution: finding equilibrium is simply the better/more common strategy. It is when genetic carriers (organisms, viruses etc) move out of their niche, that catastrophes happen most often. On a continental scale, we see this also when larger animals are moved over boundaries previously impassable (often with humans assisting transport). Rats can devastate small islands, foreign toads wreak havoc in Australia. Of course, we could argue that these examples are from planet earth, and we are considering exo-bacteria here. Arguments based on science fiction and not actual observations are fun too. [Answer] Well. Considering the Earth sustained life for millions of years longer then humans existed on this particular planet. Could I not interject that WE are the result of alien bacteria that was introduced to Earth after the former inhabitants were "evicted"? It shouldn't therefore be a foregone conclusion that we could be most likely threatened by an alien bacteria. It would rather be a more legitimate argument of our ability to adapt and develop either immunity to possible attacks, or harmonize with it as is the bacteria we symbiotically live with in our very own bellies. The evolution of the alien bacteria and our own would certainly play a part, but so would the current environmental compatibility of the bacteria. The fact it is in an early evolutionary stages from the home planet may give it an adaptation advantage allowing it to survive the often sterilizing environment of space during its journey to the new host Earth. Discovering it already exists on the planet would prove the bacteria's ability to resist extinction, and it becomes a question upon us as to whether we benefit or lose due to its presence, and if so, can we control it before spreading rampant and consuming threatened human life? [Answer] Similar circumstance produces similar outcome. It's likely that an earth like planet would have earth like creatures, flora, fauna, and other similarities. This is the principal behind lots of science fiction and science fantasy on how aliens are predominantly predatory bipeds not unlike humanity. There's actually a strong reason to believe that their exo bacteria would be so similar to ours that differences would be negligible enough as to have no significant effect on us. [Answer] ## Wipe out the microbes Another way of considering the situation is that if you have a spaceship large enough to move hundreds of humans and going at say 0.01c then the energy released by the retro rockets slowing down is easily enough to cook the surface, killing off any life in the process. (If aimed at the planet) Even without this there are other ways to wipe out unfriendly microbes. Places in the universe where you can survive without a spacesuit (or at least breathing equipment) will be few and far between. ]
[Question] [ Its the year 2050, and extraterrestrials have popped up next to the Solar System. We know they are coming our way and we know they are most likely hostile. As Steven hawking said: > > Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they could reach, If so, it makes sense for them to exploit each new planet for material to build more spaceships so they could move on. Who knows what the limits would be? > > > Leading strategists determine that war with such an advanced species will without doubt end humanity and perhaps all life on Earth. Additionally, considering they reached us first, they are so advanced that they will without a doubt win no matter what weaponry we use. So the global community comes up with a plan that could stop the seemingly given war and make the extraterrestrials change their course by making them fear us (irrationally perhaps). How could we achieve this? [Answer] Quickly ship all of our nuclear weapons up to the moon using all available space craft. Arrange the bombs on and beneath the surface to maximize their destructive affect. Then once the lunar base has been evacuated, detonate the entire arsenal. After the dust settles and the static clears, broadcast the following radio message... "The 1% power-level test worked great! Start charging up to full power and let me know when that approaching alien fleet is at optimum range." [Answer] You might be too pessimistic. The defender has huge advantages in a [science-based](/questions/tagged/science-based "show questions tagged 'science-based'") setting. He sits right on the supply dump and factory, while the invader has to bring everything along. * Cosmic buckshot. Fire a cloud of debris so that it will intersect with their course if they do not maneuver. Repeat until they are made to miss out system. * Swarm attacks. Build lots of cheap, expendable attack ships. We have to get lucky once, they have to get lucky every time we attack. * Convince them that we will use cobalt bombs to devastate Earth rather than surrender. [Answer] Build large fleets of previously "destroyed" invasion fleets. Hitler and Rommel built large groups of cardboard tanks to fool Allied spy-planes into thinking there were hundreds or even thousands of them, when there were sometimes less than ten at the given location. Large floating half-complete "Death-Stars" with scorch marks from where the resilient humans "destroyed" them, could be intimidating. Making them all hollow means we can build them faster, and looks like we shot holes straight through them. Construction crews could be made to look like salvage fleets if we used brighter burning gas for the return trip (to look like the loads were being carried BACK to earth.) one single nuke (NOT our entire arsenal) detonating a small asteroid on the outer side of the "attacking ship" would produce enough irradiated dust and debris to make it look like we had shot holes in the spacecraft outwards. Large enough conventional explosives might also suffice. Disney, Lucasfilm, and Paramount could be used to create a "historical document" that could be broadcast, and left in portable video-playing devices, then scattered by probes to the outer reaches of our solar system by "accident" as to be found easily. (Especially if emitting small amounts of radiation). Plutonium batteries would keep them active for tens of thousands of years. Lidar range finders could activate the playback once someone or something got close enough to find them. Other players could be of "alien" origin and record a record of their defeat, and a warning to their reinforcements NOT to attack earth. They would have to be in an alien language, but not necessarily in Thermian. Also... producing new versions of Independence Day would be helpful to transmit with alternate endings. The Aliens must believe humans are able to defeat invaders with our psyonic death rays, to keep them from trying to annihilate us for our technology. And if all else fails, make them afraid to take anything from us out of fear they will be assimilated by Borg nano-probes. [Answer] Make them believe that we are going to blow ourselves up. 1. Step 1: disinformation. Show them how hopeless we are 2. Step 2: we'll take them down with us. Make them believe that we accept our doom but that we will do everything we can to make it as little profitable as possible for them. Because that's what humanity would do in this case anyway right? Note that there is no worse enemy than someone having nothing to lose. That's what we want them to believe we are. 3. Step 3: make noise. Now aim at their sensors and shoot as precisely and as much radiations as possible. If you can wait until some gravitational waves come from a way they might think (like 1% chance) we produced them, it's an instant win. 4. Step 4: evil laugh. Make them believe that we are ACTUALLY mad enough to blow ourselves up if it can prevent them from exploiting our planet. Do even more noise, don't stop even if it means to blow up some parts of the planet 5. Step 5: profit. Now they can approach us at their own risk. Sure we will hurt ourselves more than we will hurt them and they are very likely to get what they want, however, we might very well get lucky and blow them up with us. The chances are very low but the danger is very high. Don't forget that they probably don't know our exact tech level. we may be able to blow up our own planet as soon as they land. If they are not desperate they'll let us blow ourselves up alone and wait until the next habitable (and safer to colonize) planet. Seriously as silly as he looks, would you approach this firecrackers armed guy: [![mad guy with explosives](https://i.stack.imgur.com/zHDpk.jpg)](https://i.stack.imgur.com/zHDpk.jpg) Even if those toys are firecracker level explosives, even if the worse thing that can happen to me are some bad scorches and burns, even if he is probably going to kill himself trying to smoke one (because that's not how you use firecrackers), I personally don't want to get involved with him, never ever. Now let's take that a step further. What if you don't even know if those explosives are C4 or firecrackers? the only reasonable answer is GTFO of here. Bonus: If you got your aligned, gravitational wave producing cosmic event they'll probably won't even TRY to check what's going on. Think the previous guy with a nuke. [Answer] Fear might be the wrong way to do it. Fear can be overcome. I want a solution which makes the invasion a bad idea logically. Assuming they're guaranteed to win an armed conflict, I'd figure out what they want and render that resource unusable or extraordinarily costly to get. * They want our infrastructure and we can't stop them from beating us? Destroy the infrastructure. We at least keep our freedom and our lives. * If they want us as meat engineer a change to make us taste terrible or toxic. (nature does this all the time) * If they want our biosphere, destroy it (oh wow did I just discover why so many smart and capable people are cavalierly destroying our ecosystem?) If you're fixated on fear, maybe figure out a way to make their young taste like bacon. So long as one human survives none of their young are safe. Humm maybe that simply makes them exterminate us. Alternatively we could take a lesson from nature on earth. An injured predator is a dead predator. If a lion thinks lunch is going to be more trouble than it's worth it will back off. Showing that you have the ability and willingness to cripple them (even a minor injury to a lion's paw could mean it can't hunt anymore). Don't try to beat them, stand up a weapon system that makes us more trouble than we're worth. [Answer] 1. Say we have a black hole generator on a deadman's switch, which was gifted to us by another alien empire who assumed we would do as much damage as possible to the invading empire's expeditionary force out of spite. 2. Send out a distress call clearly directed at the approaching force begging them for assistance, promising anything they want, then have the beacon and all radio transmissions and artificial lights abruptly cease. 3. Offer payment if they clear the minefield that's kept us isolated for so long and to be careful because they're really hard to detect, for bonus points actually have a hard to detect mine in their flight path and warn them just before they encounter it. [Answer] I would etch warnings into the rock of our moons and planets pictorially and in an invented language, to the effect that this system and its inhabitants are the property of a transcended AI von neumann swarm, the violation of which would result in swift superluminal retribution, ala Charles Stross' Singularity Sky. [Answer] > > So the global community comes up with a plan that could stop the > seemingly given war and make the extraterrestrials change their course > by making them fear us (irrationally perhaps). > > > How could we achieve this? > > > Why, we are way ahead of you. Every day, Sky Cinema and regular TV channels beam into space countless accounts of alien invasions in which the aliens invariably get their green butts kicked. In each and every one. "But", you say, "those are fictional". Well, if the aliens don't have the concept of "fiction" in their culture, which might very well be a prerogative of humans, they would have a hard time figuring that out. [Answer] > > Its the year 2050, and extraterrestrials have popped up next to the Solar System. We know they are coming our way and we know they are most likely hostile. > > > Thinking of our history and how we theat each other through time: * Jews to Filistines; * Spanis inquisition to "witches"; * Catholics to Lutherans; * European to African; * "Americans" to native Americans (Indians); * "Southern colonies" to now-called-afro-americans; * Nazi to Jews; * Japanese to Chinese (WW II); * Humans to animals;... I'm asking, do you mean "most likely more hostile than we already are"? If they are not that much hostile, say seeking only for resources for building and own (passive) defence they will be scared of how we treat the different ones among us. If they are that hostile remember that every invasion is assessed by equation revenues - costs. If they doesn't have the main tactical advantage - they cannot outnumber us they will be freaked by the idea, that we will actually unite (for a while) and focus all our efort to them. Remeber how Britain conquered almost whole world - They sorted out the troubles with Scots and focus on the others (Spain, France, anyone else). On the other hand, they can wait until we sort ourselves out for them. There most likely will be a traitor who will help them for a prize, say becoming an Earth governor for them... [Answer] Threaten whatever they are coming here to obtain, even if it means our suicide. Say they want that nice oxygen/nitrogen atmosphere. We threaten to poison it with radioactive debris. This would destroy us, but that was going to happen anyway so by denying them the resource we would effectively deter them in the first place. This should at least open negotiations for a mutually beneficial arraignment. [Answer] 1. Convince the aliens that we have developed a secret super biological weapon. Even if it not true as long as the aliens believe it then they might chose to invade another planet that doesn't have biological weapons. 2. Make an alliance with other aliens, many Native American Tribes successfully fought off European invaders for a time, by make an alliance with a European power that was a rival to which ever one they happened to be fighting. We could try something similar. [Answer] Fear = unpredictability, loss of control. I don't think that simply shooting all of our nukes to them would be a good idea. In this case, maybe they will leave, maybe not. Most probable, they get away and they will come back after they've found a way to deal our next wave of nukes. It will be a rational decision from their side and not a decision by fear. If you want them to have fear, the destruction must happen on an unpredictable way: 1. You shouldn't allow to make them possible to understand your psychology. 2. You shouldn't allow for them to have control over the events. Let them possible the only way of control if they flee. Allow them to get into the orbit Jupiter and here attack them from outward (from the direction of the orbit of the Saturn). Capture some of them, disembowel them and send them back. Next time do the same, but instead of finding the bodies of their coworkers, they should find an exploding nuke in the "package". Send them an "I want to surrender" message and kill the responding team again. Send them "collaborators" who are in the reality, suicide bombers (with nuke). If you find cooperative people in the Humanity, make suicide bomber from them. Never use all of your force against them. Never use the same methods against them. Remark: only to make fear in them is groundless. Make fear in them for a goal. The goal in this case, to "help" them to understand, that conquering the Earth is a hopeless goal for them. It would mean that you only attack them if you think they want to conquer us. Or any similar. Although it will reduce the fear in them (it makes you predictable), this is what you want and not the fear itself. [Literature, ideas, tips & tricks](http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0148). [Answer] I don't think you'll be able to scare them off by convincing them we are superior. Once they enter the solar system and there is no fleet to intercept them they'll know that we are not. The only thing we can do is to deny them the spoils and hope that' enough to convince them fighting us is not worth it. It's a desperate move akin to throwing the steering wheel out of the window in a game of chicken, but we can nuke the planet ourselves. Obviously billions will die but if the aliens are not able to land they might just move onto the next system. [Answer] You can't, the most efficient way to destroy us would be sending relativistic projectiles raining down on the Earth from light years away. This strategy has no risk, save a counter strike. It would be very challenging to convince them we have the dyson-sphere scale energy supplies to launch a counter attack, further, the attack would likely originate far from the alien's true home and industrial centers. [Answer] If you may, I would like to debunk the marked answer. I would question you, IS NUCLEAR THE GREATEST WEAPON THE UNIVERSE HAVE? We don't know what they are capable of, we don't know what their technology is and we don't even know if they know nuclear. We are limited to what we know is power, what we know is destructive, but they? In the year 2050 and some aliens reached us, could you even guess that they used nuclear to reach us? And for us to strike fear to them without us knowing what they are capable of is pure luck. What i know is, for you to be feared, you have to have something which anybody fears, what if the aliens could create black holes the size of the solar system and then turn if off again? could nuclear blast deal even significant damage to that kind of sheer force? again. We do not know their capability. And If they know ours, then, we don't have a chance for them to fear us, we fear them. That is the reality. [Answer] Aposematism is an anti-predator adaptation in which a warning signal is associated with the unprofitably of a prey to potential predators so they leave it alone permanently while Deimatic behavior is a startling effect, however it is most often used as a means for the prey to escape. Since there's no mention in the scenario as escape as a potential solution, I would defer to the former behavior. Warning coloration is the most deployed form in nature, taking it a step further than color we could deploy unappealing/discordant patterns of electromagnetic signals at them as a deterrent. Predators might innately fear unfamiliar forms (neophobia) as they present unfamiliar challenges which could potentially harm them. Using creativity which is a rarity in the natural world as far as we know, we could come up with an endless variety of unfamiliar and unappealing forms. If we show them that our planet is inhabited by beings which are at least advanced enough to take a bite out of them, they might just steer clear of earth and take the 'lower hanging fruit' of the resources on other planets. [Answer] I would say it depends on how they got here. 1. If they used some FTL drive, time to start learning the language of our new alien overlords, if they don't exterminate us that is (which is frankly the most logical move on their part). 2. If they used a sublight system that went above or near $.5c$, see 1. 3. If they are on a generation ship the size of the moon, or have multiple generation ships. We dismantled NASA so most likely, see answer 1. But if one of the stellar corporations has managed to live that long, we can launch nuclear missile satellites and scare them by nuking them. Or we could send a bunch of shuttles with ISIS soldiers on board and lots of C4 and see what happens. Or if Japan had made the space elevator by then (Japan had space elevator contests using weather balloons) they will probably be scared of us already, and we could possibly come up with a peaceful solution. All of this assumes they do not stop at the asteroid belt, and exterminate us with an asteroid bombardment. ]
[Question] [ I want to describe a world where one doesn't know how long the day will be. It can be anywhere between 18 and 30 Earth-hours. Would such days be possible in our reality? [Answer] Binary star. If you have two sources of light, you will have 4 options for night and day: double star day, two single star days, and night. These will be predictable but for a complex orbit the ABday, Aday, B day, night pattern might take a very long time to repeat, and seem chaotic in the short to intermediate term. Additionally days will turn into different kinds of days at different times of day, depending on where in the orbit the planet is. Here is an example of a wild and beautiful stable binary orbit. [![binary orbit](https://i.stack.imgur.com/bdAiP.gif)](https://i.stack.imgur.com/bdAiP.gif) from <http://sprott.physics.wisc.edu/chaos/3body.htm> If you knew the spin of the planet you could calculate what would be in the sky at any given time of the year. It will be complicated! More in my answer to this question. [Can a space station theoretically maintain an orbit around two separate astronomical bodies? Switching between the two cyclically?](https://worldbuilding.stackexchange.com/questions/91080/can-a-space-station-theoretically-maintain-an-orbit-around-two-separate-astronom/91124#91124) [Answer] It can only happen if the body has [chaotic rotation](https://en.wikipedia.org/wiki/Chaotic_rotation): > > Chaotic rotation involves the irregular and unpredictable rotation of an astronomical body. Unlike Earth's rotation, a chaotic rotation may not have a fixed axis or period. Because of the conservation of angular momentum, chaotic rotation is not seen in objects that are spherically symmetric or well isolated from gravitational interaction, but is the result of the interactions within a system of orbiting bodies, similar to those associated with orbital resonance. > > > Examples of chaotic rotation include Hyperion, a moon of Saturn, which rotates so unpredictably that the Cassini probe could not be reliably scheduled to pass by unexplored regions, and Pluto's Nix, Hydra, and possibly Styx and Kerberos, and also Neptune's Nereid. > > > Another example is that of galaxies; from careful observation by the Keck and Hubble telescopes of hundreds of galaxies, a trend was discovered that suggests galaxies such as our own Milky Way used to have a very chaotic rotation, with planetary bodies and stars rotating randomly. > > > However note that, since chaotic rotation is not seen in objects that are spherically symmetric, it cannot happen on planets, which are, by definition, under hydrostatic equilibrium and thus spherically symmetric. [Answer] You need a new source of "night". Start with a normal spherical planet with a consistent rotation speed and a subsequently predictable 30 hour day/night patterns, then add dense high-atmospheric clouds which block all sunlight from reaching the surface. Then all you need is erratic high-atmosphere wind patterns, so that surface dwellers can never predict when their daylight will be blocked by the clouds. This works best if there is some cohesion among the particles which make up the clouds makes them clump together in continent spanning masses. Smaller clumps might cause a lot of midday eclipses but wouldn't significantly effect the length of productive daylight. But when one of the big ones floated in over your city, there is no telling how long it will be before you see daylight again. All of this could be the result of an apocalyptic eco-war where nanites were released into the upper atmosphere to destroy the enemy's agriculture, or it could be natural, the result of a recent super volcano or even the planet passing through a river of space dust. [Answer] A wobbling rotation axis will do. On Earth, length of day changes through the seasons fue to the axial tilt. We don't really notice it on low latitudes. But on higher latitudes a summer day can last from 13 hours to six months, depending on where you are. Now, [the Earth also wobbles](https://en.wikipedia.org/wiki/Chandler_wobble), though very little: > > The Chandler wobble or variation of latitude is a small deviation in the Earth's axis of rotation relative to the solid earth, which was discovered by American astronomer Seth Carlo Chandler in 1891. It amounts to change of about 9 metres (30 ft) in the point at which the axis intersects the Earth's surface and has a period of 433 days. > > > (...) > > > The Chandler wobble is an example of the kind of motion that can occur for a spinning object that is not a sphere; this is called a free nutation. Somewhat confusingly, the direction of the Earth's spin axis relative to the stars also varies with different periods, and these motions—caused by the tidal forces of the Moon and Sun—are also called nutations, except for the slowest, which are precessions of the equinoxes. > > > (...) > > > One hypothesis for the source of the wobble was proposed in 2001 by Richard Gross at the Jet Propulsion Laboratory managed by the California Institute of Technology. He used angular momentum models of the atmosphere and the oceans in computer simulations to show that from 1985 to 1996, the Chandler wobble was excited by a combination of atmospheric and oceanic processes, with the dominant excitation mechanism being ocean‐bottom pressure fluctuations. Gross found that two-thirds of the "wobble" was caused by fluctuating pressure on the seabed, which, in turn, is caused by changes in the circulation of the oceans caused by variations in temperature, salinity, and wind. The remaining third is due to atmospheric fluctuations. > > > If we amped up Chandler's wobble to be of thousands of kilometers rather than just nine, this would cause days to change length much faster. This would combine with seasons for some really conplicated cycles. The fun part is that wobbles combine: > > This wobble [Chandler's] which is a nutation, combines with another wobble with a period of one year, so that the total polar motion varies with a period of about 7 years. > > > Combined wobbles make cycles much harder to calculate. So just give a few wobbles to your planet, caused by a variety of sources, and you're set. [Answer] Simulated reality. Very advanced technology in the background, i.e. the planet used to be very high tech, has orbital mirrors which control where the sunlight goes, and they've regressed. A very shiny moon would probably come close to this although that depends on how low a bar you will allow for "daylight". Now if you mean "our level of technology with anything close to normal orbital realities" the answer is "no". [Answer] This solution is inspired by the chaotic motion of the [double pendulum](https://en.wikipedia.org/wiki/Double_pendulum). * Suppose the planet's motion is controlled by different interacting effects. For example, a strongly rotating solid magnetic core, plus a highly fluid liquid magnetic mantle (unlike earth), where the mantle itself experiences chaotic currents and eddies. You'd have to handwave some of this, or figure a way it could happen and still allow habitable temperatures, but..... * Suppose also that the planet's outer mantle, being liquid, has led to numerous very thin and small tectonic plates, and superficially these look like small island groups. * Finally, suppose the planet's rotation is such that there are permanently light and dark sides. The idea would be that while the planet's motion around its star(s) is regular, there are really strong chaotic tectonic effects from the different magnetic fields and hydrodynamic motions, which mean that the islands themselves migrate around a fair bit. Islands close to the light/dark boundary could then find themselves spending 18 hours in the light area, then 30 hours in the dark area, or vice versa, at random. I'm not sure how workable this is, but I think chaotic tectonics could provide a solution, at least, for small islands and some rather tightly constrained conditions :) [Answer] # Three body problem And yet it could work! Our daytime is always the same because both the rotation and translation movements of the Earth are periodic. However, you can have nonperiodic trajectories for a planet under the influence of a two-star system, as described in the three-body problem. Another option would be a two-planet system orbiting a single star but I have not seen any report on such a thing. Under certain initial conditions these trajectories can be repetitive but could get "chaotic", leading to different periods of light and darkness Without physics or computers, daytimes would seem chaotic to the inhabitants of such a planet. In fact, under such conditions it is hard to think that pluricelular life could emerge, not to say a civilization with abstract math. Check out these links: <https://www.wolframscience.com/nks/notes-7-4--three-body-problem/> <https://medium.com/@mikeharrisNY/misconceptions-about-the-three-body-problem-and-its-relation-to-forecasting-c0c0a2bf44cc> [Answer] At some time in the past, a technically superior civilisation built a [Dyson sphere](https://en.wikipedia.org/wiki/Dyson_sphere) around their sun, to capture the energy from it. The civilisation might be a now-deceased predecessor, or could still exist, just not be on this same planet. I prefer the second if those options. For example, the sphere might have been built by the inhabitants of the 2nd planet out, just beyond their orbit (where it won't affect their planet's sunlight). It is used for specific periodic highly-energy-demanding tasks, such as powering starship launches, [immense computing tasks](https://en.wikipedia.org/wiki/Matrioshka_brain), bulk energy to matter transmutation (every day we do a short solar-energy-to-cobalt run for the steel business, depending on demand, our own bulk sources of cobalt being long used up, a solar-energy-to-platinum run for the catalyst and electronics industry now and then, and there's always a need for copper, etc), or international cat-watching-week-online, or whatever. Or perhaps it's used to recharge some kind of supergalactic communicator thing, which needs topping up an average of every day but depending on use might need charging up early or running longer than usual. It's a big energy source, so its used for these specific tasks only. The upshot is that for planets 3, 4 and 5, the sun is unpredictably dimmed to almost no light at all, when the sphere is capturing all solar output. Otherwise, when it's not, then the totality of sunlight transmits through it 100% like normal (that's how this technology works). The sun appears to fade in and out because the sphere takes an hour to power on and off - that's always been accepted as a way that daytime starts and ends, rather than anything to so with the sun over the horizon. If the sphere on and off times happen to overlap with the planet's natural day and night rotation cycles, you'll get some very long+short days and nights as well. Given tasks which require huge energy consumption, and happens for an arbitrary number of hours every day or so, inhabitants of those planets would experience completely unpredictable daytime/nighttime durations. That will be how it always was, always has been, and won't be something new. [Answer] If you're looking for a 'natural' solution - look above. If you want to get a bit more creative/artificial, have a read of "Matter" by Ian M. Banks - this includes a nest world/shell world comprised of many ever larger hollow spheres. A primitive (renaissance/early industrial age tech) civilization between two of these colossal shells is at the mercy of 'rollstars' - enormous artificial stars that roll across the terrain of the shell above theirs, between, over, and through mountain sized crevices that cause irregular patterns of night and day that can only vaguely be predicted, often overlap, and are impossible to predict more than a few weeks ahead. [Answer] Various plans have been floated in various places to modulate a planet's sunlight, either by adding shades to reduce it (to make Venus less toasty, or perhaps to offset our own global warming) or adding mirrors and lenses to amplify it (to make Mars more toasty; KSR's Soletta in his Mars trilogy is a good example). Positioning such devices and keeping them on station isn't going to be easy... they're massive, and the pressure of sunlight has to be offset somehow. They're also quite fragile. A few damaged, off-station or otherwise out-of-control sunlight modifiers might conceivably create twilight or eclipses at intervals that may be or become predictable given enough time and brainpower brought to bear, but for some period of time they could easily seem quite random. [Answer] No, this is not possible. The length of day is determined by the rotation period of the planet around its own axis. The rotation speed would have to change dramatically to accomplish different day-lengths. What could be similar is a strange arrangement of twin planets, where the rotation axis of the two planets spinning around each other is not at 90° of the solar plane, so the day length would change throughout the year for certain locations. Otherwise, since these two planets would be tidally locked, the rotation period of one planet (one planet day, so to speak) would be the same as the rotation period of the two planets around each other. [Answer] Cixin Liu, in "The Three Body Problem" describes evolution on a planet in a trinary star system. The orbits of three stars in relation to each other is so complex that it seems random and civilisations collapse numerous times when caught by an unexpected freezing or heating cycle. The Three body problem is a [scientific thing](https://en.wikipedia.org/wiki/Three-body_problem?wprov=sfla1) (Wikipedia) and is generalised as the "N-body problem". Cixin Liu's book is well worth a read and seems entirely relevant to the scenario you are exploring. [Answer] One possibly way would be to have your planet orbit very close to a very dim red dwarf star. So close that it would normally be tidally locked to the star with one side always facing the star and one side always facing away from the star. But instead the "planet" is actually a giant, Earth-sized natural satellite or moon of a gas giant planet that orbits in the habitable zone of the star. So instead of being tidally locked to the star it will be tidally locked to the gas giant and the star will rise and set on the moon so the moon will have days and nights instead of eternal day in one hemisphere and eternal night in the other hemisphere. Now change the axial tilt of the planet, and thus of its moon, so that it is nearly 90 degrees, and thus the axis of the planet and of the orbiting moon will be almost pointed in the plane of the planet's orbit around the star. That means that at one time, the north poles of the planet and the moon will be pointing almost directly at the star, and the northern hemisphere of the moon will have constant day and the southern hemisphere will have constant night. And when the planet moves 90 degrees along its orbit around the star, the direction to the star will now be at a 90 degree right angle to the direction of the planet and moon's axis, and both hemispheres of the moon will have normal days and nights based on the period of the moon's orbit around the planet. And when the planet moves 90 more degrees along its orbit around the star, a total of 180 degrees from the first point, the south poles of the planet and the moon will be pointing almost directly at the star, and the southern hemisphere of the moon will have constant day and the northern hemisphere will have constant night. And when the planet moves 90 more degrees along its orbit around the star, a total of 270 degrees from the first point, the direction to the star will now be at a 90 degree right angle to the direction of the planet and moon's axis, and both hemispheres of the moon will have normal days and nights based on the period of the moon's orbit around the planet. And when the planet moves 90 more degrees along its orbit around the star, a total of 360 degrees from the first point, it will be back at the first point, the north poles of the planet and the moon will be pointing almost directly at the star, and the northern hemisphere of the moon will have constant day and the southern hemisphere will have constant night. And at intermediae positions along their orbit the moon will have days and nights of varying length between those extremes. And what will be the relative length of the moon's orbit around its gas giant planet and their common orbit around their star? A giant, Earth-sized habitable moon orbiting around a gas giant should have an orbital period lasting about 1.5 to 15 Earth days - possibly longer or shorter. A gas giant planet and its habitable moon could have a orbital period around a tiny red giant star of only about 5 Earth days and still be within the habitable zone of the star. The four planets of star TRAPPIST-1 that orbit within its habitable zone have orbital periods, or years, of 12.4, 9.2, 6.1, and 4.05 Earth days. Thus at first sight it would seem possible for the "day" of the moon to be several times as long as its year. The article "Exomoon Habitability Constrained by Illumination and Tidal heating" by Rene Heller and Roy Barnes Astrobiology, January 2013, discusses factors affecting the habitability of exomoons. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3549631/> It states that for the moon to have a stable orbit, the orbital period of its planet around the star has to be at least nine times as long as the orbital period of the moon around the planet. So if it takes about 1.5 to 15 Earth days for the moon to orbit it's planet, it should take the planet at least about 13.5 to 135 Earth days for the planet to orbit their star, in order for the moon to have a stable orbit. So assume that the orbit of the moon around its planet last for exactly 2.0 earth days and the orbit of the planet around it's star lasts for exactly 16 moon days, or 32.0 Earth days. So when the moon and planet are in the first position mentioned above, the northern hemisphere will be in a day that lasts for several days of the moon, and the southern hemisphere will be in a night that lasts for several days of the moon. Eight Earth days, and four moon orbits later, the planet and moon will be in the second position 90 degrees along their orbit mentioned above, and the moon will have a day-night cycle like Earth's, but the days and nights will be twice as long as Earth days and nights. Sixteen Earth days, and eight moon orbits after the first position, the planet and moon will be in the third position 180 degrees along their orbit mentioned above, the southern hemisphere will be in a day that lasts for several days of the moon, and the northern hemisphere will be in a night that lasts for several days of the moon. Twenty four Earth days, and twelve moon orbits after the first position, the planet and moon will be in the fourth position 270 degrees along their orbit mentioned above, and the moon will have a day-night cycle like Earth's, but the days and nights will be twice as long as Earth days and nights. Thirty two Earth days, and sixteen orbits after the first position, the planet and moon will be in the fifth position 360 degrees along their orbit mentioned above, and thus back in the first position, and the northern hemisphere will be in a day that lasts for several days of the moon, and the southern hemisphere will be in a night that lasts for several days of the moon. And in intermediate positions along the orbit the lengths of days and nights will vary between the above extremes. Also there will be positions in their orbits where and when light reflected off the gas giant planet may provide considerable illumination to the moon, and there may be positions in their orbits where and when the gas giant planet eclipses the star as seen from the moon, giving the moon an eclipse longer than eclipses on Earth, or a much shorter night than usual. Of course the example I gave, when the orbital period of the moon was exactly two Earth days long, and the orbital period of the planet around the star was exactly as long as sixteen of the moon's orbital period around the planet, was highly oversimplified. It would be an incredibly unlikely coincidence for one orbital period to be an exact multiple of the other. And you may be able to use a program to design your star system and try out various arrangements of your moon, planet, and star to see which gives the best variation in day length. If you want to complicate the cycles of light and dark on your world more, you can add another star to the star system, giving the moon another source of light and maybe of heat as well. The distance between the star that the planet and the moon orbit and the other star should be at least five times the distance between the first star and the planet and the moon. So the other star should be at least five times as far away from the planet and moon as the star that they orbit. And if the second star has the same luminosity as the star that the planet and moon orbit the light it gives to the moon should be less than 0.04 times the light of the primary star. But of course the other star could be the more massive and brighter star in the star system, and thus it might be possible for it to give to the moon a lot more than 0.04 the amount of light the first star does. So sometimes a place on the surface of the moon might be illuminated by the near star, sometimes by the far star, sometimes by both stars, and sometimes by neither star, thus being in night. And sometimes that place might be partially illuminated at night by light reflected from the gas giant planet, and sometimes not. The rotational period of the two stars relative to each other would not be an even multiple of either the moon's orbital period around the gas giant planet or the planet's orbit around its star. This will make the light-dark cycle on the moon more complicated. It is not certain that the two stars would orbit around their center of gravity in the same plane that the planet orbits its star. The two orbital planes might be highly titled relative to each other. And that might make the light-dark cycle on the moon more complicated. And if you want to make light-dark cycle on the moon even more complicated, you can make one or more of the two stars a close binary star itself, thus adding one or two more orbital periods to consider. If you make one of the stars in your system a close binary, sometimes the two stars will be seen close together in the sky, and sometimes they could be maybe five or ten or fifteen or twenty degrees apart in the sky, meaning that one would rise or set sometime before the other. And it is possible that the brighter star would sometimes eclipse the dimmer one, or the dimmer star would sometimes eclipse the brighter one. So if you make both stars in the system close binaries, a place on the surface of the moon will sometimes be illuminated by all four, by three, by two, by one, or by none, and the varying apparent brightness of those stars will mean that some of them will make the day much brighter and warmer than others. So I hope my suggestions show the way for you to design a a star system where a habitable moon has a very complicated light and dark cycle, one which can be calculated and predicted but which is very complicated and hard to calculate and predict. And be sure to check other questions and answers about habitable moons orbiting giant planets. [What are the day and night fluctuations for a moon orbiting a planet the size of Jupiter?](https://worldbuilding.stackexchange.com/questions/137322/what-are-the-day-and-night-fluctuations-for-a-moon-orbiting-a-planet-the-size-of/137368#137368)[1](https://worldbuilding.stackexchange.com/questions/137322/what-are-the-day-and-night-fluctuations-for-a-moon-orbiting-a-planet-the-size-of/137368#137368) [Answer] Yes, you could. If your civilization was advanced enough to create a ring-world (such as in Niven's Ringworld series), then it could be assumed that they are also advanced enough to create (randomly) changing shadow panels. [Answer] One could have a planet that could be similar to Earth except that an asteroid belt orbits closer to the sun and has sufficient density and size to erratically eclipse the sun. This would be nearly impossible to predict, although it might be hard to find sufficient parameters for a good eclipse frequency. [Answer] This sounds pretty basic compared to some of this stuff, but why not just have a planet with very very large rings? Would it not be conceiveable that a massive, complicated ring system could block out the sun to various degrees in a virtually (if not totally) random way? [Answer] The short answer is no, this can't be done for a planet. While you could have a planet orbiting 2 or more stars, that planet would be savagely inhospitable to life as we know it. If you had a life form that could handle temperature changes of hundreds of degrees Celsius over the course of one full orbit then maybe, but if you want a planet with a reasonably consistent environment then you need a stable, reasonably circular orbit around a single star. You can get variability in the day/night cycle from a variety of things, but all of them are completely predictable. Two options from our own experience: * Axial tilt - produces seasonal variations just like here on Earth. * Eclipsing bodies - other objects (like our moon) can block all or part of the illumination from the star. Also in our solar system but away from Earth, there are planet-sized moons orbiting Jupiter which regularly pass through Jupiter's shadow. This is also completely predictable and regular as clockwork. So assuming that you want your planet to be habitable and stable you're not going to be able to find a natural method for changing the day/night cycle that isn't completely predictable. Nothing that fits with the science of our universe at least. Given that, it's clear that any environment that has a random element to its day/night cycle is artificial. It might take the inhabitants a while to twig to this, if they ever manage to get past the inevitable problem of trying to explain the universe with such obviously bad information. [Answer] On a planetary sized object the overall day cycle is going to be fixed. Anything that changed the rotation rate in reasonable time would also generate enough heat that you would have a molten crust. You may be able to come up with ways that the split between night and day changes. Start with a longish rotation period, says 30-50 hours. * On Earth the axial tilt causes seasons. This creates very little variation at equatorial regions to months long variation at the poles. At my latitude (Edmonton, AB Lat 54º North) we basically end up with a 8.5 hour day in winter, and a 15.5 hour day in summer. Twilights are extended for both summer and winter. So the day length varies by about a factor of 2 over the course of a year. * Posit a large, but low density moon in near synchronous orbit, going around the same way as the planet rotates, but somewhat slower. In near synchronous orbit, it would appear to be almost stationary in the sky. This would create frequent eclipses. The combination of large diameter moon, and slower than sync orbit makes for longer eclipses. This wouldn't affect a large area, but it would add variation. You they would be frequent, nearly every day if the inclination of the moon's orbit is close to the equitorial plane of the planet. So during eclipse season you would have a bunch of them once a day. If the moon's orbit is slightly tilted relative to the planet's rotation axis, you would get a shifting eclipse season over the year. You need a low density moon to keep from getting excessive tides. The large size makes eclipses more frequent and longer lasting. Keep it the same diameter, but drop it's mass by a factor of 64 (A moon made of pumice) and move it closer by a factor of 8. This will still give you bigger tides than Earth has. If it's close to synchronous orbit, however the tides rise and fall are very slow. (You get 2 tides per moon rise, in near sync orbit the moon is in the sky for weeks at a time) * Make the large moon very white. Our present moon has the reflectivity of asphalt. If you covered it with titanium dioxide it would be brilliant white, we'd get 8 times as much light/square meter. Having it a factor of 8 closer increases the illumination by 64, so you end up with 500 times the light of our present moon. This still isn't sunlight, but it's enough light to easily see. This will make effective 'we can ride, and go to war' variable daytime lengths. If the moon is in a near synchronous orbit, the moon stays almost stationary, but it will change phase over the course of each day. (The sun provides about 400,000 times as much light. But our eye responds to the logarithm of illumination. This is around office lighting. ]
[Question] [ (For my own needs) I write stories that are primarily fantasy, but with very strong touch of modern technologies (modern technologies converted to magic world, for example magic bomb that behaves like nuclear bomb, magic rods that give cold light, climatic change released and given by magic, and so on). That world (including lower gods) was created by group of thirteen gods called The Creators of the world. All gods accept that people need to believe in them, but they hate if people ask them for help, Hence they try to teach people to not ask for help. Currently they kill (with great pleasure) clerics and other people that dare to ask gods for help if any else mortal could do that (of course, some lower gods sometimes make an exception; mostly if it serves for their own). ... and sometimes they say words like do it in such way or search for someone who will make it. Is killing people that dare to ask the gods for help the best way to achieve getting people to not ask for help? Is there a better way to teach people to not ask the gods for help? [Answer] Killing "offenders" prevents them from learning from their mistakes. Responding instead with a painful or embarrassing curse/disease that lasts for a short time will cause humans to quickly figure out the cause/effect relation here. After a few short months, the only people still asking the Gods for help will be either desperate, drunk or teenagers. The first category may be worthwhile listening to, the second are due a month-long hangover and the third can be punished with acne, as usual. [Answer] Killing worshippers just because they talk to you might indeed be an overkill. There are certainly ways to mitigate that: * Self-help must be a virtue. If you help yourself (or other humans), gods will help you too. Sort of. * Gods are there to manage the universe and global concepts such as elements, nature, death and so forth. Everyone knows they care little about individual humans and should not be distracted lest the world gets out of control. That volcano probably erupted because someone was bothering gods too much. * One should never ask for something for himself, but only for something for many others. (So if someone prays for help with a great plague the gods might be actually inclined to help.) * Strongly limit the possibilities for effective praying. You are only allowed to contact the gods in major temples, on major holy days, after great rituals. And you'll be sacrificed at the end. * There could be only one day in a year when mortals are allowed this. (Which the gods will probably spend drunk on ambrosia.) * Also, make sure to use the concept of sin a lot. If the asker is sinful or asks for something for sinful people, it is only fair the gods curse them for their wicked ways. (Oh no, somebody was selfish again!) That should make mortals paranoid about asking for stuff. * Make the domains/spheres of influence clear so that people have to ask specific gods and make sure they address the correct one. * Alternatively make their domains unclear but the asker must still address the correct god, risking serious insult. * Asking all gods for help is right out and fast track to hell. * Oh, and yes, hell as an institution would be handy as well, something the mortals can get visions of. * The gods are such amazing and supreme creatures that the very act of them starting to pay attention to you, puny mortal, could turn you into dust. One does not simply 'talk' to gods. Rather, to attract the attention of the creators of the world one should create a work of art that embodies your prayer. If it is beautiful enough and your wish is noble, they may choose to help you. (The gods can ignore or kill anyone that speaks to them and can at leisure ignore all the pieces of art the mortals create. Perhaps they'll choose one once in a while to keep up the appearances.) [Answer] Don't eliminate asking for help - people are likely to do that, or expect help without asking, because that's what they expect from omnipotent beings. But establish an semi-formal "currency" of worship that can be "spent" on the granting requests, and have a history of such requests being granted so it's not like our rare-to-never "miracles", but more common place and part of the culture. Make it expensive. For example, one year of solid worship might build enough "credit" to grant a request for a good harvest. A lifetime of worship might build enough credit to grant saving someone's life from serious illness. Make it optional for the god to grant. It's also up to the god to determine the "price" at the time of asking for help and thus determine how much credit will be left. The price would be "spent" regardless of the grant being made - it's more an "application fee", so people are taking a risk that if they don't have enough credit, they'll blow all they have and get nothing. This would also create an interesting situation at the end of someone's life. What to do with your saved up worship credit? Do you take it with you into the after life? What implications would that have? Do you spend it all on a "last request" as you're dying? Do victors in battle show professional courtesy by waiting a few moments before delivering the death blow to give the defeated an opportunity to make a "last request"? And is it possible for the defeated to make his last request that (s)he not die (like a "saving throw" in D&D or an "extra ball" in pinball)? Would that be dishonorable? If granted, would they have to spend their remaining (granted) life in worship/penance/service/philanthropy? It could make an interesting backstory. Can people "pool" their credit? Can a village spend all their collective worship to save the village from destruction the lava flow, or an invading army? Can you borrow worship to spend on something worthwhile? What would be the interest rate? How would you pay it back? Can you buy it, trade it? What would it cost? Can you extort it - force others to give their worship credit to spend on your request? Would a god accept borrowed/bought/extorted worship? The concept could have macro-economics implications. Could "wealthy" countries support professional worshipers whose job it is to build "credit" for the government, which spends it as they see fit? Could you tax worship credit from the populous? If fighting a war, could there be war bonds for worship credit, where the donated credit is spent winning the war, but you get back more credit later on as dividends. [Answer] There is a tried and tested system for this used by most of the major utilities, phone companies and airlines. Have an answering system takes you through an infinite loop of menus. If you finally get through to a particular god's answering system it would put you on hold playing Vivaldi's Four Seasons until your patience runs out. Why re-invent the wheel? [Answer] *CROM* Have people believe the gods frown upon weakness. And that strength is pleasing to the gods. Only through struggle and suffering can one truely get the blessing of the gods. That valor and endurance are the best form of prayers. And the gods do not do parlor tricks. Imagine responses to prayer like this... If you tie up your camel, its less likely to wander off. Got 2000 people to feed? I'm a god, not a caterer. Walk on water? Meh, get a boat, you showoff. Damned boatman's got 20 kids to feed. Piss me off badly, and I might decide you're not worth dropping a rock on. So, divine gifts? Hope that one can endure, strength to do all one can, and hopefully a sharpened piece of steel that does not break at the wrong moment. What else does one need? or to borrow that wonderfully pithy line from Conan the Barbarian. > > "Crom, I have never prayed to you before. I have no tongue for it. No > one, not even you will remember if we were good men or bad, why we > fought, or why we died. No, all that matters is that two stood against > many, that's what's important. Valor pleases you, Crom, so grant me > one request, grant me revenge! And if you do not listen, then to hell > with you!" > > > That's a man who clearly is looking forward to a nice brawl in Valhalla. [Answer] The Gods have the same problems that arise whenever you try to scale an operation: ### Delegate, delegate, delegate!!! The Gods needs to appoint their high priests to handle the process of receiving and prioritizing these requests. These elders will be advised of the various priorities of the employer and will bring forth those tasks which are important to be done. When you send an email to a VP in my firm, you make it very short and clear. If there's a deliverable, it's clearly stated "please deliver \_\_\_ by \_\_\_". If there's a question, it's in its own paragraph. There's no fluff, you get maybe four or five sentences to get your point across, Blaine Pascal style. This would be very much the same. Of course, this means putting trust in your priests, but you unless you want to spend time dealing with all the peasantry and their stupid grandmothers needing healing and stuff, this really is the only way to do it. And they have to believe they're being heard because it only takes one God who actually delivers to make it so everyone has to or they all flock to that one! Free market religion, etc. Now exactly this is implemented has a wide variety of ranges, but at some point this God has to realize that delegation is the only way to scale. [Answer] Can your gods not just directly instil 2 ideas in the minds of humans? 1 We exist 2 Don't ask us for help. Really, really don't ask us for help. Go directly for the brain, don't bother with symbols, signs and mysticism. They're open to all sorts of misinterpretation [Answer] There is an excellent magic system which it is possible to create that allows your living gods to handle prayers. If the system is done right, the Gods themselves will have to do very little work. Your Gods should demand the following: * Pray to them only at a certain site, or at certain times (per another answer). * Only congregants with a certain degree of reputation can ask a prayer or question the gods. * Responding to other people's prayers, as a supplicant yourself, will earn you reputation with the Gods. * Other supplicants may upvote or downvote your prayer. If you attain enough downvotes your prayer service is closed, and you are immediately put to death. * You will also be expected to award them points (for their prayer). * Bounties can be awarded for an especially good sacrifice. * Non-constructive responses to prayers should be confined to verbal discussion only. * Verbal replies are for brief discussion and factual clarification about the nature of the prayer, which god, etc. * Anyone asking "[Whose god is greatest?](http://blog.stackoverflow.com/2011/08/gorilla-vs-shark/)" questions will immediately be put to death as they are "not constructive" in a prayer setting. * Extended discussion should be done in private chat, not in temple. * Prayers must be answerable. If your prayer is subjective, you will be asked to clarify your prayer, start a new prayer, or else put to death. * If you attain 50+ reputation, you are able to chat with other congregants (within the temple). * If you attain 150+ reputation, you are able to chat with other congregants in a room of your choosing. * Name-calling the gods in the midst of chat will result in instant death. * If you attain 10,000+ reputation (or mana points, whatever you want to call it) you are promoted to high priest. This enables you to respond to hidden prayers. [Answer] Your question is a bit vague on why exactly gods need belief: * They somehow screwed up when creating the world and now require worshippers to not die? * It turns out mortal can generate copious amounts of a Very Important Resource and they want it for pantheon domination, further world-making and/or for use as poker chips? * They prefer to have their worlds infested with obedient little sapient annoyances to having their worlds crawling with unruly little sapient annoyances, because the former are more likely to scurry away when you need them to scurry away? and, more importantly, what kind of belief they need: fanatical devotion, love-filled faith, fearful reverence, any-kind-is-fine? In quite a lot of cases, killing the mortals who dare to waste your time with their incessant nagging is a perfectly fine solution as long as you do that immediately after they ask you in public, preferably surrounded by common folk and believable witnesses, so cause-and-effect relation is crystal clear and the word spreads. This way, you can get quite a lot of hushed, terrified belief and establish yourselves as the "Stop, you violated the law natural order!", "there's a long list of things they really don't want you to do", "like Olympians but without favours" kind of gods. Of course, you would probably need to do some other tricks from time to time, but eventually your position should be cemented and people should stop asking. However if that kind of public image is not a viable option, you might want to rethink why your gods are doing everything to set it up there are two other options. The most effective route has already been mentioned by others: you need to tell them. Either directly (word of god, pieces of writing ascending down in a beam of light) or indirectly (pass down the holy commandment that taking even more from the gods than they already gave you is unclean, abhorrent and sinful). The second most effective route would be to take inspiration from stories about monkey paws, deals with the devil and lazy/malevolent genies, and grant every single wish - but grant it completely wrong, tongue-in-cheek, bonus points if it results in some sort of a visual or a situational pun. I can't think of a good example, but, let's say: A general asks for an army to defend him from incoming horde? Spawn 50 chickens in adorable, tiny, completely useless helmets. With manicured, completely dull claws. And make them inedible, too (you can't eat something that poofs out of existance when it's poked too hard). And when he repeats himself, spawn another 50 slightly above his head, because slapstick. And if he tries to explain he needs something ferocious, make the chickens peck away his good boots, his fancy prayer pants and his oh-gods-I-paid-four-villages-for-this cloak. (And have them immediately pass out from exhaustion, of course. We don't want them to be too competent.) [Answer] So you want them to keep praying but don't want them to ask for anything during the prayers? Basically outline that the deal is: On Earth, the people must serve the Gods, but they get their eternal reward when they get to Heaven. Since the Gods are real, they should have a much easier time proving that Heaven and Hell are real. The purpose of prayer then is to thank the Gods for creating the world and giving them the chance to get to Heaven, to "check in" any tasks, homages, sacrifices, other dues to the Gods, and to say things to their formerly dead friends & relatives (now in Heaven if they were good), though not necessarily to hear anything back. I suppose you could call that last part help from the Gods (i.e. to pass on the message) but they could set up a sort of magic radio which is automatically initiated with the sucking-up type prayer (which is passed on to the Gods themselves) so they wouldn't have to get involved themselves every time someone wanted to send a message to their Granny. [Answer] The gods are likely to run up against the superstition problem, i.e. that random rewards lead to superstitious behaviour (<https://en.wikipedia.org/wiki/B._F._Skinner#Superstition_in_the_pigeon>). This means that even if they kill every worshipper who asks for help, inevitably someone is going to ask for their sick child to be healed, they'll be struck down, and their sick child will happen to get better on their own. The rest of the family may then say: "Ah! It is because they prayed at the hour of noon that our gracious Lord granted their plea, though it cost them their life." This kind of thing is quite hard to get rid of, particularly if people are well aware that the gods could fulfil their requests if they wanted to. To avoid this I suggest either: 1. The gods have very clear, and restrictive rules. E.g. if you want to pray successfully it needs to happen between 23:50:55 and 23:51:00 on the 14th of January. Any other prayers receive a response from the god that says something along the lines of "Your prayer is important to us, please hold." The flaw with this is that they will have to grant some requests. 2. The gods both do the opposite of what was requested, and kill the worshipper. The major flaw with this is people getting wise to it and praying for the opposite to their desired outcome. However, assuming the gods are omniscient, it should be fairly easy for them to spot this. [Answer] Trigger alert for all those that believe in religious teachings: atheistic reasoning ahead. Let us first look at what we mean by "a god". In real life, the label "a god" has always been assigned to entities that are supposedly omnipotent or at least supernatural. Also "a god" is a benevolent being that wishes good for us humans (those that do not are usually called "demon" or "devil"). Finally — and crucially — the "gods" in real life never actually manifested themselves in any tangible and verifiable way. Hence: "a god" is more or less wishful thinking, the unproven belief that there is someone out there that is looking out for us. That is what we mean by "gods" in real life. What you have there is not that. Sure, your beings are omnipotent but 1) they can and obviously will manifest themselves in a tangible manner, it does not require faith to know they are real and 2) they are callous towards us. So your beings are not "gods" in any traditional sense. What you have is a very cranky version of [Q from Star Trek: The Next Generation](https://en.wikipedia.org/wiki/Q_(Star_Trek)). So those are not "gods", they are powerful jerks. Why would people turn to them in the first place? It is like running to Donald Trump with your credit card bills and expecting him to pay them for you out of the goodness of his heart. It does not matter to him that you made an oopsie and are a few hundred short on paying them this month, that is your own lookout. So your problem kind of solves itself fairly quickly. The reason people turn to "gods" in real life is that there is enough uncertainty about their existence that you can keep calling on them, attribute good things to their name and bad things to just bad luck or that they have an ultimate, greater plan. In your case there is no uncertainty; they do exist, and asking them for help would not come up in the first place, or would be quickly discouraged in any which way you want to come up with. [Answer] The Gods need to be active enough to engender belief but make it clear they don't care about humans They can do this by making numerous appearances, basically live where the humans can see them. This should generate the required belief. However, when someone asks for help from the Gods, visit them with some punishment that makes it clear that it's divine retribution. Revoking the retribution when the supplicant recants their request for help will go a long way towards reinforcing the knowledge that the Gods aren't there to help. [Answer] The simple solution is to never answer prayers. Obviously that doesn't work in this context because people know that these gods and one actual case of them intervening or the rumor thereof is enough to restart the issue all over again. So, they should/could: * limit themselves to certain kinds of actions * demand payment of some kind, preferably something costly and the sort of price you can't or won't pay twice. * enforce some kind of confidentially geas on those they help or one that simply compels them to do something or act a certain way. making them do something unacceptable in their culture will discourage others from seeking aid from that source (e.g. force them to sleep with anyone who asks OR always tell the truth OR help those in need regardless of the cost or sacrifice involved) require that the party involved do everything that they could have before asking for help, even things that person would never dare * only intervene in cases of mass loss of life or global catastrophe * smite anyone with impure intentions, assuming they can tell. only someone who has no concern for their own wellbeing will even bother asking or even seeming to ask An important question is how the "gods" feel and whether they care about the fates of those below. They could be concerned or even care deeply and yet rather not be called upon constantly to solve every little scrape, splinter, heartbreak, etc. Most of these would either be to create fear or insinuate total, utter indifference. Alternatively they could just intervene regularly enough that the demands/request are small an easily ignored. You know, the dictator's guide to keeping the people blissful and ignorant. [Answer] Firstly, the whole idea of gods implies that humans (or whatever sentient beings there are in your world) are not omniscient, and thus are not all-powerful. If there are gods, then anyone lower than a god would automatically look to them for help: it's natural and instinctive. Thus, why would gods exist if not to help those below them? Humans exist not really to help those below them because they have their own needs to attend to. But a god needs nothing, he already has everything. Thus, he should be helping those who need it. If your gods really do not like people asking them for help, it would be useful to explain why. Perhaps someone had once asked them for help, and it resulted in something terrible? Secondly, I find it difficult to reconcile a world with magic, and a world with gods. Having magic implies that magic-wielders are capable of more than normal people, which blurs the line between them and gods. Perhaps you could place a more distinguishing factor, which justifies humans being 'allowed' the use of magic, and yet explains the presence of gods. Finally, one possible way to ensure people do not ask gods for help would be a public punishment akin to a branding and libelling. Such a person would be shunned by all, solving the issue. The offender realises his mistake in asking the gods for help, and the people around him would avoid doing the same, because they see that asking the gods for help would not solve their problem, but instead would make them an outcast. [Answer] Let the community moderate themselves. Priests are not only responsible for making the prayers, but also collectively decide which prayers are to to be made. Give reputation points and more senior positions to those who moderate well. [Answer] I'm not sure if this is strictly speaking an answer, but here is a world where the setup makes sense. Take one part quantum theory and one part Norse mythology. Stir with the order and chaos axis which I always find more interesting than good and banal evil, add a touch of Cthuluesque horror. This is a universe where chaos has almost won. The earth is a small bubble of relative order held together by the gods, adrift in an unmeasurable chaotic void. It is a failing world. Soon enough even the gods will die, but us mere mortals hope enough time remains for our small lIves and our grandchildren's. We absolutely need to believe in those gods. They are our anchor against the chaos. In this world, chaos can break though the orderly fabric that we call reality at any moment, revealing things that first destroy our sanity and then rebuild us as soulless and motivelessly malign agents of chaos. At such a moment we pray to the gods. We are their chaos warning system. When we rightly raise the alarm, they hasten to repair the fabric of reality. The might even save our lives, though that is very secondary to saving the world itself. People who pray for other reasons ... at best they selfishly distract the gods and thereby imperil the world. At worst, they subconsciously want to destroy the world. The former may get a warning if there is any time to spare. The latter have to be sacrificed if this little bubble of order and sanity is to be preserved. The chaos can also hear their prayers. A dark vision. Ragnarok cannot be much delayed. The gods themselves would pray if they knew to whom or what such prayers could safely be directed. ]
[Question] [ So we already know that [flying creatures are good at attacking castles](https://worldbuilding.stackexchange.com/a/6479/54229). But what about a flying castle attacked by ground creatures? Let's say we have ourselves a medium-sized castle built on a [driftrock](http://theedgechronicles.wikia.com/wiki/Flight-Rocks), attached with a heavy chain to the ground 800ft below. For the purposes of this particular edge of the world there exist flying creatures like birds and dragons etc. (and obviously giant flying rocks) but we cannot use/tame/control them. How does one attack / lay siege to such a fortification? I mean, you could attempt to cut the anchor chain, but then the whole endeavour floats away on the breeze - plus you make yourself an excellent target. One usually sieges a castle to get the stuff inside, or gain a valuable location, not to make it float away... Useful info: * We're in a medieval-esque fantasy world, at least as far as technology is concerned. Light use of magic is fine, but minimal handwaving preferable. * Let's say the castle has supplies for a year (food, weapons, ...). Obviously therefore no-one there will need to go groundwards. * The usual way into the castle is with a crane. Large wicker basket for people and crates for goods. * The inhabitants of the castle have access to the bottom of the driftrock. They can open access hatches to shoot, or abseil down the side of the rock. You may not necessarily be safe if you're standing underneath. [Answer] Let's revisit the premise that the sky-castle has a year's worth of water stored on it. As a corollary to this premise, we should assume that the stored water won't become stagnant or otherwise undrinkable. With minimal bathing and cleaning, just cooking and drinking and basic hygiene, the castle's smelly troopers still require about 5 gallons (16 L) of water each day. That means the castle has over 1750 gallons (6,630 L) of water, weighing 14,500 lbs (6,630 kg) and occupying a bit over 6.6 cubic meters for EACH person defending the castle. So the castle might be a floating fortification - but it's also mostly an enormous water tank. All you need to do is empty the water out of it, one way or another, and then the defenders will capitulate (or die) in a couple days. One way: Reel the castle down a bit, and build vast bonfires under it to cook the water out. When the defenders dump irreplaceable water to quench the fires, then build more bonfires! Most of your besieging army will be collecting firewood and clearing detritus (and dropped sewage), but that's what happens when you besiege a well-stocked flying castle. Another way: Use your trebuchet and arbalest bombardments to crack the castle's cisterns and let their water leak away. Another way: Use kites and balloons (and trained animals if available) to lift flammable cargoes, and dump them on top of the city. The defenders must use their irreplaceable water to fight the fires. Yet another way: If your besieging force is too small to constantly fight water with fire, then simply gird your treasury, discipline your forces, and wait a year for them to get thirsty. We have no information on the climate, culture, or architecture, so no idea how much additional water, if any, can be harvested from rain/snow/fog. Unless 100% can be replenished, it won't make a difference - the siege will merely take longer. [Answer] 1. From a safe distance, your sappers excavate a tunnel. The tunnel leads to the tether point of the castle's anchor chain. 2. Bring the tether down into the tunnel from below. Winch it along the tunnel. 3. You will winch the castle downwards. Defenders of the sinking castle will see their chain disappearing into a hole. They can rappel down and enter the hole to try to stop what is going on, but your battle badgers are right there. 4. When the castle is on the ground, you may enter by typical methods. If this was a castle that was built to be a floating castle, it may not be fortified in the same way as a land based castle would be. Alternatively, the inhabitants may see fit to surrender as their defenses might all be premised on height advantage. [Answer] As others have said, a year-long siege is probably the way to go, but... # If you aren't patient enough for a siege Here are some ideas for how you might actively attack a floating castle and force it to surrender: 1. Gain a height advantage. Height is a huge advantage for archery, and I'll bet that the castle's main defense is archers firing down at targets below. They probably can't fire up more than 50-100 feet, and their arrows would have little force even if they could. So you could attack from above using hot-air balloons, dirigibles, or even hang-gliders if there's a convenient mountain to glide down from. As the attacker, you can always go get more arrows when you run out. Wear them down by constant attacks. 2. Turn their advantage against them. Instead of dragging their castle down, as Willk suggests, consider letting them climb a bit. By attaching a new tethered chain to the 2nd link up, and cutting the bottom link, your attackers could let the castle rise up another 800 feet. For maximum effect, wait for a tremendous thunderstorm, then let them up to get a closer view of the weather. (Side note: realistically, the castle would probably be pretty frequently struck by lighting anyway. But let's say it's not high enough, until the attacker lets out the line.) After the storm, send a messenger and threaten to add another thousand feet if they don't surrender. 3. Attack by crane. A good old-fashioned Trojan Horse strategy would be best executed during a rainy day when visibility is low, arrows are inhibited, and it's hard to burn the crane. The first basketload of warriors is disguised as civilians (they don't actually have to be in a wooden horse, just don't let them look like the enemy). They launch a surprise attack when they land (or later, during the night watch?) and, instead of opening a gate, they're seizing control of the crane, defending it while they haul up a second basketful of soldiers. This could make for some exciting action as the tide turns every time another basket arrives. A diversion (such as the aforementioned hot air balloon attack) might draw the defenders away as part of the plan. [Answer] ## Use flying rocks as your siege machines If there is one flying rock there are other flying rocks as well. Use them as a base for your siege. As a general rule - get some flying rocks (they need to be large, but much smaller that the one utilised by the castle as a base), chain them to the ground/platform and use as a base for your attack. You can use them in various ways: ### Archer posts Make a posts for your archers that gives them enough protection and enables to shoot efficiently slightly downwards. Use a bit longer chain than the one used by the castle so the archer posts are over the castle and shoot from the above. You are less vulnerable to backfire from the castle since it's always easier to shot downward than upward ### Hammer Balance a flying rock with regular rocks in a way that makes it easy pull the rock down with a significant force. Attach two long chains (longer than the one used by the castle) to the rock, with additional chain reaching ground attached to the holding chain. Place the holding chains on opposite sides of the castle. Now pull the additional chains with as large force as possible (possibly the chain has to go through some ring attached to the ground so that you pull parallel to the ground) to throw the rock down into the castle. It works as a huge hammer. ### Landing ships Use a similar appliance for a rock but balance it so that you can put some troops on top of it. Now when the rock is pulled down and hits the castle your troops can jump down and attack the castle defenders. ### Drop bombs You can use various ways here: * take flying rock as a base, fill it with stones and a small crew. Using chains control it so that the stone flies over the castle and drop stones you have. You can use other things, hot tar or boiling water for example. * attach stones to small hot-air balloons. Launch them so that they fly over a castle. Now use archers (see above) to pierce the balloons dropping the stones on a castle * similarly to the previous way but rather than using archers use some simple time trigger to pierce the balloon after a specific amount of time that ensures it's over the castle ## Relocate castle Since you have access to the chain base, you can use it to detach the castle. Since you don't want it to drift away, use other chains to control the castle so that rather it floating away it goes where you want to. You might need to do multiple re-chaining or something like that but it should be possible to move the castle anywhere you want. ### Mountain as a siege machine Pull the castle to the mountain, with a steep slope, that you can use to attack the castle. ### Starve on the sea Pull the castle to the sea and attach it to the sea bed. Then sail away and wait one year until defenders starve/run out of supplies. Later just come back and collect what's left. ### Bad weather You name it - freezing winter or a scorching desert Sun. Just get the castle somewhere were you don't want to stay for a long period of time ### Dragon's nest We may not be able to control dragons, but locating a nice supply of food (i.e. castle full of people and their edible supplies) near their nest should drag them for a feast. They will do the conquer work for you. ## Smoke them If something is up in the sky, it is vulnerable to smoke. Build large bonfires so that the smoke goes in the direction of the castle, add whatever you can to make it as smelly/poisonous as possible. You'll need to move your bonfires probably but just keep them in the smoke until the morale is so low they will beg you to allow them to surrender to you. ## Cut oxygen supply I don't know how high can a flying rock fly. But if you can reach over 10k feet with it you end up with an oxygen deprivation. The higher the better. At 20k feet your defenders will soon die due to the thin air. Just make sure the additional chain you have to add is strong enough to pull the castle back to the ground once your defenders are done. [Answer] If I'm not mistaken, "laying siege" to a castle or town means to cut off supplies into or out of the city until they ran out of supplies and surrendered to your men, and sieges could last for months. That crane you outlined seems like the perfect target to capture or destroy, which will cut off at least a large chunk (if not all) of the people's ability to get into or out of the castle. From that point, it's just a matter of shooting down, blocking off, or capturing any other means the castle has to supply itself and waiting them out. The besieging army could easily put up decent enough defenses against any expected underside attacks, and maybe take some potshots of their own at people inside the walls to decrease morale. The attacking army could even start trying to set fire to things inside the floating city via catapults or arrows shooting flaming shots, or whatever brand of fire magic you like; storehouses and homes would be good targets if one wanted to shorten that food supply and/or lower the morale of those inside. Medieval warfare is all about that morale management. [Answer] If the chain is taut like a guitar string, all you have to do is play it. The vibration will drive the castle dwellers crazy, and might even cause property and biological damage. Every chamber in the castle will potentially act as a small resonance chamber as well. To play the chain, use it as target practice for trebuchets. Hit it once, and you've got it calibrated for the next strum. Use something softer than the chain's material as ammo in order to avoid damaging it (too much). --- If the rope is not taut, your engineers may find a way to yank it. Pull it taut and let go, and every castle dweller will become a reddish goo stuck to a wall. [Answer] good answers above: starve them out, pull them down by the chain. You can also smoke them out by lighting enough fires upwind of the city. but that is all very mundane. One "epic" idea is to unbalance the city. The wikia page you linked implies that the city is levitated by a single small rock at its center. So if throw enough rocks onto one side, or knock enough rocks down, you can tilt the city. Or you can attach a second chain near the edge, and pull down (or cut the main chain) Finally, same wikia page says that flightrock can be killed by a "stormphrax crystal". Hire some rogues, and task them with infiltrating the city (via grappling hooks), and install that crystal. [Answer] ## Spin it There are many ways of exploiting the chain, one even suggested spinning around its center by twisting the chain. However, I would suggest spinning around the chain base as more effective way. Get a few horses and have them pull the chain around its base, contrary to twisting the chain this would allow the inertia to gather over longer time. Given enough time the [Centrifugal force](https://en.wikipedia.org/wiki/Centrifugal_force) would solve all your problems with any defenders. This also gives an easy way of demolishing the fortifications if you decided so, few hours after the defenders left the castle flying over the horizon the fortifications would follow. [Answer] 1. Find a flying rock of similar size (in this country of flying rocks, they are probably not so rare) 2. Attach 3 ropes on its sides 3. Make sure its bottom flies at about the same altitude as the enemy rock's fortifications 4. Employ 3 groups of 10 horses to slowly move the rock until its bottom impacts the enemy rock's top. If the enemy start throwing stuff, use longer ropes. 5. Slowly move it around, crushing all of the fortifications, and more if necessary, until surrender. [![enter image description here](https://i.stack.imgur.com/M6hZt.png)](https://i.stack.imgur.com/M6hZt.png) Advantages over other methods: * No deaths on your side: Make the ropes a bit longer than the maximum reach of the enemy's weapons. * Surgical: Just destroy the fortifications, not the UNESCO-classified library nor the unique-in-the-world jewelry workshop. Keep your reputation seat by not indistinctly killing or burning everyone including civilians. * Cheap: Other methods require a lot of resources such as wood. Here you just need ropes (maybe chains) and 30 slow horses. * Eco-friendly: No need to burn the wood from all forests around. * Persuasive: Frighten enemies. Swords and arrows do nothing against a huge rock scrubbing your small territory at will. [Answer] Seems like a simple blockade in a circle around the city would work fine. Maybe a trench and barricade going the full circle around to keep people out, and some archers to shoot at anyone attempting to lower themselves down during the duration of the siege. The blockade should be large enough to prevent fire from above reaching the ground units. Basically a donut shaped camp around the lift zone. In addition, you could design an oversized ballista to shoot projectiles into the city. I recommend using a hollow headed arrow that caries a biological agent such as rotting flesh into the city as a form of biological warfare. Bonus: If you find a smaller floating rock, you can drag it into the castle rock as a siege weapon, mostly hurting moral but potentially causing damage depending on how you use it. Double bonus: Has no one suggested climbing the chain? Send a single man up the chain on a dark night and have him instal some kind of eye for a rope or chain into the rock. You now have your own way of getting up to the fort. Slowly work your way to one of the access hatches and sneakily use it to ferry in soldiers. [Answer] The point of sieges isn't to knock down the fortifications, it's to prevent supplies from entering the castle and forcing surrender before the population starves to death. Now if they have a year's worth of supplies that would make for a long siege, but it wouldn't be unheard of. Candia was sieged for 21 years. Also if the only way into the castle is with a giant crane, you probably don't even need that big of an army to maintain the siege, so even a multiyear siege may not be too bad. Assuming the castle didn't have any allies that could come to it's defense. [Answer] Destroy the foundations Your floating castle has a huge problem: it's foundations are completely exposed (assuming they've built to protect the rock that's keeping them in the air). Ground castles make good fortifications because the only thing an enemy can ideally strike at is the big thick stone walls you've built around it. The quickest way to end a a ground castle siege is to mine underneath the walls so that they lose structural strength and collapse either on their own or to your siege weapons (see the term [undermine](https://en.wikipedia.org/wiki/Undermine)). All your attackers need to do is simply build a siege weapon that can reach the castle (cannonballs could go pretty far, as could trebuchets if you don't want black powder in your world) and start blasting chunks out of it's base. Your valiant defenders are soon going to realise that they have two choices: surrender and come down alive, or don't surrender and come down with the castle when it breaks apart. If the castle base is protected by the driftrock? Even better! Any mason will tell you that if you hit a rock enough times in the same place, it cracks, usually in half. The threat of either of these scenarios would be enough to force a surrender within a few weeks. [Answer] ## Whirlwind These nobs are so proud of their flying castle now are they? They might change their mind after a magically created whirlwind that violently shakes and spins them. Since the castle is anchored to the job should be easier as the target is relatively stationary(though you'll make that change) If the driftrock obeys the rules outlined in the wiki you can start a huge fire and use the wind to channel the smoke to the flying castle. Once heat has brought the castle back to the ground you can attack them with conventional means. ## Economics You could also do it the financial way. Take over all the big banks. Exaggerate/lie about the trade deficits between your countries and raise tariffs to emphasise your Ground Castles First foreign policy. Convince everyone else that castling the sky is a violation of international law and institute punitive sanctions. Make speeches denouncing the attack on freedom of travel implied by weaponising the sky and embargo them. Spread rumours about 'Skyxit' separatists to spook the markets. Any trick to devalue their currency should be used. Acquiring a monopoly in a key import or export works too. This way you don't even need to lay physical siege to them, you just need to deliver the message that their princesses will soon be maids and tavern wenches in some other country. ## Regime Change Finally there's the CIA option. Forment unrest from within with saboteurs and agitators, throw your support behind the enemy leader's political rivals. Raise an army from within with the help of highly trained 'advisors' you'll have to put in place beforehand. When the coup is finally launched you should support it with a large conventional invasion. It's important to seize control of the cranes and the bottom hatches first so you can easily deliver reinforcements...of good will of course. After all, you only sent your army to liberate the oppressed people and restore the rule of law. [Answer] Castles are military assets that play a role in the balance of power for a region. They are strong holds that allow a small army to cast a shadow of power over a larger region. When they come under siege by a larger force they must await for reinforcements. A floating castle becomes an asset you can move. Cut the chain and drag the castle out of that region and you've gained power and control over that region. You don't have to way siege upon the castle and try to out wait those inside. You're battle is one of time to move the castle before reinforcements arrive. People inside the castle would counter an attack by dropping anchors and trying to prevent their castling from being moved. So moving the castle would be the objective of the battles. One trying to pull it away and the other trying to keep it where it is. [Answer] Take a bigger, flatter floating rock. Use chains to hold it close to the ground right below the castle, and then let go! For bonus points unteather the castle and let it float really high, so that the rock following it can gain more momentum [Answer] What sort of governance does the current population of the ground kingdom have? Now assuming we are in some sort of socialist or spin of socialism (which I'm assuming we are as we're jealous of someone else's ability to form a floating city in a land supposedly devoid of any technology of notable merit, and want to take it away from them), or perhaps a very unjust king, then I would imagine it would be alright for the governance of said population to simply take things from its populace and justify it by some means. Therefore I'd like to suggest this government raid every farmstead and peasant run grazing land for all creatures of the bovine species; Oxen, Auroch (assuming we'd still have them), Buffalo etc. Once the countryside and all grazing land has been picked clean of all bovine creatures, we will distribute these cows to questionable market traders not under the banner of our united socialist republics and thus still in the ecstatic heights of capitalism, in all markets across the globe (assuming this is a globe and not flat, nor balanced upon the back of some sort of animal, or heaved upon the shoulder of a native deity). We will send our economical leaders (the ones we haven't killed in our quest for global socialist revolutionary supremacy, so I'm not assuming they'd be all that great really, however the large quantities of bovine creatures should make up for that) to negotiate with these market dealers, and ascertain absolutely ungodly amounts of magic beans. Under the cover of darkness, with the obscene numbers gathered in our revolutionary peasant war band, we will have them all smear themselves in black so they will remain unseen, and then we will plant the entire stock of magic beans around the floating castle. In the morning, when the denizens of the floating castle are yawning, they will see all beneath them devoid of life, they will assume our peasant revolt has dispersed, little to their knowledge that they now float upon a forest of giant beanstalks, with which our brave warband climbs to wreak socialist destruction upon the cloud bound citadel. Once we have shown the sky fortress the errors of its capitalist ways, we shall distribute the pulpy remains of the beanstalks to the people, and install our completely legitimate government upon the heavenly throne, cast the world off of the shoulders of the deity balancing it, and cast our own form of jealous judgement upon all creature and denizen of the known world from unseemly heights, whilst occasionally having to pop our ears and catch our breath adjusting to the new unbearable altitude. [Answer] At 800ft up, the defenders can't really see what's going on. And their arrows are kind of useless. Longbows had a range of around 600 feet. The arrow still falls with gravity, but with only enough force to injure an unarmored opponent. Any attackers are going to have platforms held above their heads while they build fortifications. So the simplest answer is to build catapults, build shelters from above, then pull the castle down. Once the castle is pulled down, standard siege tactics work, my favorite, throwing dead animal heads and parts over the wall to spread disease. And the best part is you don't have to bring them all the way to the ground, leave them 50ft in the air, lob disease at them, then let go and let the castle rise back up 800ft. Now they are stuck with these dead heads, they can't escape, and you just made them all sick. Maybe your troops should shield themselves from the impending aerial diarrhea and dead bodies lobbed over their own walls at your troops below. [Answer] Detach the chain from its base and reattach it to a wheel placed on a bearing that spins, with an arm to push it around. Have Conan or any sufficiently strong Barbarian to spend their days spinning the wheel, constantly rotating the now spinning castle. After a few days, stop the wheel, and watch as the extremely dizzy and unbalanced defenders fall from the sky [Answer] Carve the floating rock(s) into masts of floating sailing ships, the amount,sizes and shapes of the sails would determine how fast, and the type of ship they are. Flying carpets for people as well as Djinn and Elementals. ]
[Question] [ This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. A simple enough question, but one that [Grimmsdottir](/users/6429/grimmsdottir) and I agonized over. Basically, what would enable close-ranged fighting between space fleets/ships? We both agreed that having gargantuan ships sniping at one another from billions of miles away was no fun, so what would be a good method to force battles to be more personal? Some ideas we have considered: 1. Powerful phlebetonium shielding that necessitates the use of boarding parties. 2. [Minovsky Particles](http://en.wikipedia.org/wiki/Universal_Century_technology#The_Minovsky_particle) (or an expy thereof). The harder the science, the better. But if hard science makes this impossible, soften the science instead of merely saying 'it can't be done'. [Answer] As a general rule, it seems natural that you would want an opponent as absolutely far away as possible. The further away they are, the fewer tools they have to hurt you. However, there are a class of situations that demand rapid feedback to be effective. These show up when there are many unknowns that must become known before your attack can succeed. Consider a randomized chaotic shield. If you just bombard it, you can see that, statistically, it defends against your bombardment. However, what if we don't have a way of making it perfectly random just yet? What if they are chinks in its algorithms which could be exploited? What if you could "walk it off" the spot you want to hit before you actually hit it? This is not actually all that far into science-fiction. These sorts of things would actually start to naturally come into place if your shields were trying to observe and react to the oncoming salvos. It's rooted in chaos theory. In Chaos theory, there is a concept called Lyapunov Time. Roughly speaking, a chaotic system acts roughly predictably under this time constant. However, after that time constant, the amount of unpredictability grows exponentially. It takes time for light to travel in space. If you get feedback on "what state the shields are in" that is 2 minutes old, and the Lyapunov Time for those shield is 1 minute, you have virtually NO idea what their state is when your next salvo lands. You might as well be fighting blind However, get down to within a light-minute from the opposing ship, and now you can start to see a little bit of predictability out of the opponent's shields. You see openings, but you can't leverage them because you're too far to launch a salvo. Now get really close. 15 light seconds, 10 light seconds. Now you start getting close enough where not only can you predict what the shields will do, but you have time to respond and attack with that information. Now those shields are a lot less of a threat than they were before! Interestingly enough, one can use a very similar modeling approach to explain why, in real life combat, it is so important to have ground troops going door-to-door in some particularly chaotic situations. [Answer] ## Interference Shields An impenetrable shield would cut down range drastically by simply not being passable by weapons fire. If you wanted to shoot, you'd have to be inside the shield. Problem is; you can't normally get there, because any shield that blocks out weapons fire would also block out ships. Potential solution: an impenetrable shield that interferes with other shields. If you have two shield generators and their shielded areas touch, they start overlapping and fizzle out over the contact area. This means a shielded object can enter a shield, and once it does, is free to open fire on anything else also inside said (combined) shield. This allows you to fly into close range and then open fire, but at such short distance that ultra-firepower would basically just destroy you as well. One requirement is that the technology to create the shield be incredibly expensive, otherwise there's no reason not to simply throw out shielded missiles. The results of such a shield on a capital ship would be interesting, to say the least. For example; if you destroy the enemies' shield-ship, they will be trapped inside yours. This may or may not be a good thing (as they'll either fight to the death or surrender immediately) It also means fleet tactics will be common, since any ship without a shield-ship nearby will be a sitting duck (but only to enemy vessels that are also operating outside a shield-ship). You also cannot reliably split or merge fleets into a portion smaller than a single shield-ship and its escorts, since the other ships are trapped in there with you. You could only dock at a shielded spaceyard, or a planet with a massive planetary shield around it (to protect from enemy raids and the hazards of space, like asteroids). If the shield works by simply inverting the speed of any object that collides with it, you also have a good argument against rapid-fire cannons to simply shred everything in the shield; the shells and scrap from the vessels would bounce off the inside of the shield and turn the entire bubble into a giant deathtrap. Ships would need enough armor to withstand the floating debris that is left at the end of a fight, and they'd need to be careful with their guns because missing is risky. Alternatively, you could say that interference is only possible between two shields that are roughly the same size. Imagine if the shields dent inwards on contact based on their relative size difference, before starting interference. Then a ship with a very small shield bumping into a very large shield would have its shield dent all the way inwards, where it would destroy the shield generator, causing the ship to be destroyed. But a much larger ship would have less of a dent (and more space to absorb it) and after a short push, the shields would start interfering. This allows your shields to act like semi-solids (or plasmas?) and reminds me a bit of soap bubbles. You still can't have shielded missiles piercing a vessels shield (both because a missile has a very small shield and because the high speed means the shields won't have time to start interfering before you slam into the other one) but it does allow shields to be much cheaper. This will change the dynamic of your world quite a bit, so it depends on the other goals of your story-world which is better. (Credit for the alternative goes to Falco) [Answer] To stay within the bounds of plausible science, I will eschew the concept of impenetrable shields. Unguided projectiles are rather useless if the target has sensors with enough resolution to spot the incoming missile at distance - they can just dodge or deflect it. This would also require the target to be relatively stationary for a very long time and the aggressor would need an exceedingly precise launcher to actually hit anything. Even shotgun tactics are unlikely to work, because space is big. Guided missiles will be vulnerable to countermeasures. Multiple ships (or just a deployed decoy) painting the incoming missile in whatever EM ranges the targeting system uses will effectively blind it, rendering it as useless as an unguided projectile. Get a little more energetic with your countermeasures, and short-range energy weapons can kill the missile - burn off the sensors or slag the maneuvering thruster nozzles and it is effectively neutralized. Presuming the target is not relatively stationary, the missile probably wouldn't even be on a collision course anyway - just let if fly harmlessly past, but a little more energy would deflect it onto a different trajectory just in case it might still pose a threat (large explosives set to the last estimate of target's location). It may be possible to fire massive volleys of guided missiles in the hopes that the target cannot cope with them all. Unfortunately, your missiles still have a long distance to travel while vulnerable to countermeasures, and those that survive get close enough where shotgun tactics will work for the target destroying them. This also requires huge quantities of munitions to attempt (scaling up with how good the countermeasures are, with the advantage to the defender), which would be both cost prohibitive and severely limit your choices as you blow it all on one shot. I would expect energy weapons to be far more popular than projectiles, simply because you have to haul around all that mass for your projectiles, but energy weapons do have an effective range. If you try attacking from too far out, the beam will be so spread out that the energy imparted on a square meter basis may be too low to be effective. If the target gives itself a little spin, so the patch of hull being hit over time keeps changing, you might not be doing much more than slightly warming it up. Of course, if you have a high enough energy output, it might be lethal even if dispersed, but that would probably take absurd amounts of power. Closing distance reduces the time a target has to dodge or counter incoming missiles (physical ammo is limited so make each shot count - don't fire until you can see the whites of their eyes), and allows for a much tighter focus on energy weapons (imparting more energy per square meter to the target). [Answer] Missiles in space aren't are useful as you might think [Here's a NASA report on how nuclear weapons would behave in space.](http://history.nasa.gov/conghand/nuclear.htm) The major points are: > > First, in the absence of an atmosphere, blast disappears completely. > > > Second, thermal radiation, as usually defined, also disappears. There is no longer any air for the blast wave to heat and much higher frequency radiation is emitted from the weapon itself. > > > Third, in the absence of the atmosphere, nuclear radiation will suffer no physical attenuation and the only degradation in intensity will arise from reduction with distance. > > > In short - no blast, no heat, but lots of radiation. If your ships have very good radiation shielding (which would be very useful in space outside of combat, too) then only a direct hit or near miss is going to affect you. Non-nuclear weaponry will be even less effective - with no blast or heat transfer, a direct hit would be required for any damage to happen. As others have mentioned, it's pretty easy to come up with ways to disable long-range missiles, let alone simply causing them to miss. If a ship is close enough that a missile can't be disabled in time, it's likely that both ships would be affected by the radiation of nuclear weaponry. This also means that small fighters can be very useful - they would be very hard to hit directly with missiles. They would also be able to pretty much completely mitigate EMP damage - if an EMP missile is launched, electrical systems can be shut down into a mode that prevents any damage and then rebooted after the EMP has passed. These fighters would allow you to get missiles close enough to be deployed without being disabled before arrival. A salvo of missiles at close range is another potential tactic, though more risky - if you blow off a chunk of their ship it might come flying straight at your ship. A close-range salvo would probably use non-explosive missiles to avoid this - instead of trying to blow up the enemy ship, you'd be simply trying to punch holes in their hull. [Answer] Science has absolutely nothing at all to do with the answer. It's a question of resources. If you need to capture an objective intact, then you send in regular troops. If you don't then you destroy it while you are as far away from it as you can be. Today's wars often start with pinpointed strikes launched from sufficiently far away that the enemy can't counter them; only to be followed up later with pacification of the populace with "boots on the ground." In cases where that pacification isn't necessary, then the boots never hit the ground. There's a reason the phrase "Nuke it from orbit. It's the only way to be sure." is a thing. Close combat to take over land or equipment that can be bent to your side's purpose may make sense, as long as the value of the land or equipment exceeds the costs of the potential losses in taking it. If not, then the fall back is simply to deny it to the enemy and, therefore, hitting it from far away. If the technology is sufficiently alien then there might not be a reason to grab more than a couple ships or space stations for research purposes. If the alient planets aren't fit for human habitation, or necessary for human needs, then there won't be a reason to capture them. the tldr; is that there has to be an actual reason for them to get up close and personal. Otherwise you're just spinning a "because I said so" story. [Answer] I'm surprised no one mentioned this, but a (to me) obvious solution is to depend on sensor deflection, scattering, or deception technologies (the equivalent of stealth, but adjusted to meet the parameters of your situation). If you can't see what you're shooting at, you have very little chance of actually hitting anything. This only applies to ships that have these technologies built in, but it would require close range, potentially very close, in order to get any computer-controlled targeting systems to work at all. Missiles can be equipped with onboard sensors, meaning that they could be launched in the general direction of a known target even if the exact location of that target is unknown to the launching ship. You would depend on the missile to find its target on its own. The further the missile travels, the less payload it would deliver (assuming that fuel contributes to and potentially makes up the entirety of the payload), and eventually, the missile would turn into drifting space junk or a moving, dumb space mine. Since you're dealing with potentially heavily armored or shielded ships, missiles must be equipped with potent payloads. They may be much more expensive than energy weapons and they are usually limited in supply. Also, a deflection shield would often easily avoid missile damage. Once a missile is deflected, the attacked entity would easily be able to track the source of the missile and launch a counter-attack, so missiles would be useful for long-distance ambush attacks against small enemies, but failing to destroy the enemy would turn the missile into an effective invitation to a counter-ambush (at long distances, the initial attacker might not know for sure exactly where the target is, so a counter-ambush remains a possibility). Energy weapons dissipate with distance. This effect could be drastically increased by dissipating shields. The shield itself would only be effective against energy weapons, but it would be capable of dissipating such weapons while potentially recycling the energy to increase shield strength. Close-range would be the only option in this case because natural dissipation is reduced to a point that would allow at least some of the energy weapons through the shields. [Answer] Let's first make it clear: dogfighting in space is extremely unlikely with current technology due to immense fuel requirements: quick maneuvering -> extreme changes of impulse -> burn tons of fuel (comparable to mass of the craft) -> need to take more fuel onboard -> heavier craft -> need more fuel to change impulse... If there is no [major breakthrough](http://en.wikipedia.org/wiki/Spacecraft_propulsion#Hypothetical_methods) in high-impulse propulsion tech, there'll be no dogfights in space. Also, orbital physics puts some serious constraints on possible maneuvers (if you played Kerbal Space Program, you know it), BUT it also makes quite awesome possibilities for hi-adrenaline low-orbit tactics without requiring tons of fuel (imagine Gravity with fighters instead of debris). If the planet is small and dense, its low orbit will look like a hi-speed circular death race track! (It'd be an interesting side-research to calculate which celestial bodies provide best conditions, or to choose physical parameters of a planet when designing a fictional one). As a bonus, it can provide "civilian background" to discourage from inaccurate shooting. Also^2, [here is some neat analysis](http://gizmodo.com/5426453/the-physics-of-space-battles) on how physically realistic space battles may look like (you've probably read it, so just in case). And [here is some fruitful discussion](http://www.reddit.com/r/askscience/comments/2me2f0/do_orbital_physics_mean_that_dog_fights_in_space/) on dogfighting in space. Finally, consider dogfighting inside a gas giant atmosphere. [Ice giants'](http://en.wikipedia.org/wiki/Ice_giant) atmospheres contain more methane and ammonia than Jupiter-class giants, which can probably be used as fuel in an appropriate engine (that's a topic for a separate research). Still sticking to dogfights? All right, let's keep it more or less hard-sciencey. Current spacecrafts are extremely fragile. If a dangerous space debris is detected in the path of the ISS and it is too late to maneuver, the lids on Cupola are closed, solar panels are rotated in parallel, the crew gets into spacesuits and prepares for emergency evacuation in Soyuz. There is some layered shielding on the most vulnerable parts of the ISS, but it can only protect from small debris. Armor is heavy and bulky. Even the battle-oriented spacecrafts of near future probably won't be strong enough to survive a direct hit of a missile, a volley of projectiles or piercing laser shots. Larger ships may afford some multilayer graphene shielding, but still, most of the time they'll bet on reflection, deflection and maneuvering ahead of time. Spaceships are easily seen against space background, either visually, or in IR, or in radio. The closer we are, the easier it is to detect, and the harder it gets to stay stealth. A bit harder when against a planetary background. The closer are the spaceships, the more weapon possibilities they have: * Over large distances (light-minutes or more), only relativistic weapons are feasible. It is a battle of AI-guided prediction modeling, small randomized maneuvers and lots of patience. Assuming we have a good low-dispersion hi-power laser/maser/particle-beam. (Btw, consider a story with battles of AI predictors and an exploited/faulty RNG which gives not-good-enough random maneuvering, putting the ship in danger). * Medium distances allow for mass drivers, which accelerate small projectiles to almost relativistic velocities. Deploy several thousands of them into the predicted target position and around it. And again, have some patience and a good prediction model/algorithm. * Close encounters would allow using guided/smart missiles without waiting for months, but they are heavy to carry around and to accelerate, can be countermeasured, and it is probably easier just to deploy huge swarms of them from the mainship at a distance and leave them do their job. Maybe even outfit them with their own beam weaponry, turning it into a drone fight (which is also easier, cheaper and safer for the crew, although less heroic), or shrink them down into a micro/nanoswarm. The closer are the spaceships, the fewer defense possibilities they have. Missiles, drones and other slow macroscopic objects can be taken down/redirected/blinded with beam weaponry ahead of time. Volleys of relativistic bullets are much harder to dodge, so we'll have to rely on random maneuvering and those puny armor sheets we have. Hence, mass-drivers can be used in both medium and close encounters (I just can't imagine an efficient countermeasure besides maneuvering, armoring and blinding/disabling enemy ship). As for beam weapons, besides maneuvering, we may try reflective (in appropriate wavelengths) surfaces, but another possibility exists: if there is only one source of enemy fire, we can shoot a deflector missile in their way, to change beam paths ahead of time (gravity lensing itself may be enough to make the beams miss). Or use dispersive cloud countermeasures. Maneuvering, design and CM. Since maneuvering is the most reliable method of long-term survival in space battles of any distance (and since we have soften our fuel requirements), the smarter and more unpredictable we are, the better (AI can do the job, while keeping the crew safe in the mainship, but again, not too heroic). So, the ships should be light, be outfitted with enough reaction wheels to quickly turn around, may have several maneuver engines and several weapons looking in different directions, and be filled up with all kinds of countermeasures (jammers, optical/IR/MW/radio decoys, dispersive clouds, beam deviators, anti-missile beams, drones/nanoswarms, etc.) to get closer to each other. The ships should probably be of some fancy shape to make barrel rolls in 3D more efficient (no need to be aerodynamic). And those manned fighters should better be accompanied by numerous drones. To sum it up: There may be some situations where close encounters are possible (limited space inside some asteroid cave, for example) but there aren't many of them in outer space. Low-orbit is more feasible. Or maybe a scenario of protecting a space station/habitat from non-destructive invasion/boarding. There are numerous technologies that would prevent ships from getting into a dogfight: algorithms of control and prediction, long-range beam weaponry, AI-controlled drones/swarms. This can be facilitated by prohibiting them in your scenario (religious fear of AI, "undignified" use of drones and long-range beams etc.). And of course, some technologies are just not advanced yet to provide a dogfight: economical high-impulse propulsion (the most problematic one), efficient shielding, more rigid spaceships, cheap space launches / interplanetary travel, efficient weapons for space usage. Also, remember: ships are small. Space is immensely huge. Consider sticking your spacefights to some locations of interest (as localized as possible; otherwise they'd just lazor down each other from afar). [Answer] It depends on the level of technology Low Tech Like knave mentioned, if the tech isn't that advanced dodging becomes relatively easy at long ranges. However every single shot/attack and dodge/reaction is costly, making long range combat horribly not cost/effective, this would lead to closer range combat, but high risk as changing course vectors, or "dog-fighting" can not only exact a huge toll on resources but also damage the ship. Fights would be won by extremely brilliant planners like a game of chess where it's all about who place themselves in the best close range position for near-kill shots. Ships would be heavily armored (close range combat) not only for protection but also for strategic purposes, allowing the ship to take X amount of damage for it's own destructive attack to take place at the best opportune moment High Tech Not much point in having close encounter battles unless stealth is involved OR the goal is to capture and not to eliminate. The high level of technology would mean even though in a close quarter battle one of the sides probably gets disabled early on, they still retain fighting capabilities at short range for when the attackers close in on them to capture/pillage/kidnap them. High maneuverability Bombers are also a viable idea but would mostly be tiny fighter vs huge ship fights (possible launching its own fighters to intercept). Either that or a cheaper solution to building huge high tech long range weaponry ships, much smaller ships equipped with cheap to manufacture short range high power weaponry. Their strategy would generally be to approach bigger ships undetected to immediately make use of their weapons before the bigger ships can fire on them. [Answer] I would give each fleet some sort of large force field carrier, that shields the entire fleet from sniper ships. This would force them to get up and close, entering the force field before even being able to attack. If both parties would have such carrier ships their would be a massive close quarters battle at each battle, trying to destroy the other shield so that the sniper ships can destroy the enemy fleet. Another idea could be awesome ship manoeuvrability. Rockets would be easy to deflect or shoot out of the sky so I guess the sniper ships would mainly use beam weapons or mach launchers. From the large distance apart I think it could be possible to have ships be fast enough to dodge most of the attacks. This would result in an endless dance between two parties and as the battle goes on they probably would go in for the kill at some point. [Answer] Simple long-range scanning would allow your ships to see and therefore avoid or destroy any incoming missiles, torpedoes etc. Anything except lasers, and dispersion means those are ineffective at long range anyway. Ships have to get in close to not telegraph their attacks. If you're looking for big flagships and little fighters trying to board them, the simplest explanation is that there are no weapons that can bring down an entire cruiser. Pinpoint lasers, after all, are only damaging a single pinpoint, and wouldn't be noticed on a hundred-meter ship, let alone five hundred or however big you're picturing. At close range, any missile powerful enough to cripple your enemy's cruiser is going to severely damage yours as well. So the only practical way to disable a cruiser is to board it and incapacitate the crew. The only tiny voices of reason you have to silence are the ones coming up with more practical superweapons. :) [Answer] I think most fights would be close quarters in space. Assuming FTL travel isn't possible and distance must be traveled linearly. No wormholes or other methods to 'cheat' FTL travel. Then most fighting will be done by drones. Either AI or remotely controlled. People are ludicrously hard to transport. We are easy to transport in that we can perform complex operations in order to make adjustments mid-journey. We are difficult to transport in that we require protected environments, heat and pressure. We also require sustenance and we expire quickly. So, why are people being transported across space and why don't other people want those people to be transported across space? If you can't get an answer to that, then all fighting is done by drones and against drones. Drone's can be small, light and agile. Any shots from further away could be easily dodged. All fighting must be close range just to hit another drone. Anything large enough to be hit at range would be large for a reason (cargo) and would be better to be hijacked by a hacking drone... which could be small enough to avoid all long ranged attacks. [Answer] Battling from the longest effective range only makes sense if destruction of the enemy is your objective. If ships carry highly valuable, cargo, crew, components, etc. then you need combat to be much more precise. In fact, this is the only reason a ship would bother with a boarding party too. One SF series proposed that FTL took a human with very special and extremely rare genetics to make an FTL jump. In such a Universe, that human would be the most precious commodity and many engagements would start with closing to a range in which fire can be very judiciously used to cripple and not destroy opposing craft. Many such actions would end with a boarding action to capture this psionic jump enabling person. Another priceless (or at least pricey) commodity might be a cargo of quantum entangled particles. You could postulate that they would be useful in communications, ciphers, etc. Or magnetic monopoles (none have ever been found, but they would be highly valuable if they were found). Perhaps humans are rare and we need to preserve their genes too. The point is high valuable and fragile cargo would require ships to not engage in combat trying to completely annihilate each other. Or it could just be a set of war conventions that both sides follow. [Answer] For whatever reason close-contact is necessary, why not use remote probes? For Dune shields that block fast objects, a smarter torpedo drone; if explosives don't work or contact is needed for the canopener, use a drone. Think swarm of bees, not one lion. To get past that, you need a requirement of both contact and large mass. The frigate can't deploy anything smaller because it must be as big as a frigate. Maybe the shields can only be breached by similar shield generators with power and mass behind them. Real inertia can be required to anchor the effect. Or applying the field to too-small of a ballest will destroy it, as mass is needed to soak it up. If technology doesn't work, use politics. Like medeveal heraldry, it's all about the players and personal posturing. You're putting on a show for your subjects, rivals, and allies, not just stopping the ship. Add to that the people are backed up or immortal or flying telepresence or something, so just blowing it up remotely would not do much good. [Answer] Ships are expensive. People aren't. It takes years of effort and trillions of dollars to build a gargantuan space battleship with all the latest obscenely destructive toys, but it takes only a few months and a handful of dollars to train a combat grunt with a pop-gun and a can-opener. If every battle started with the commanders on both sides wanting to come out of the battle with more ships than they entered it with the fighting would switch from big ship-to-ship engagements to close-quarters combat between boarding parties. This situation would only be encouraged if ship weapons where so accurate and devastating that the only outcome of any ship-to-ship shootout is mutual destruction. So we'd end up in a situation where massively armed ships are too afraid to fire at each other in case they damage an expensive prize (or get instantly annihilated themselves by returning fire) while boarding parties are favoured as the first line of attack. I know this answer is not exactly what the OP wanted (no actual close quarters ship-to-ship combat) but I think it's an interesting take on the problem. [Answer] Make Iron Man a real thing If energy sources are capable of being small enough to enable a superhero sized problem for opponents, than the large mass and inertia of a ship becomes problematic. A skilled soldier in a wild suit of powered armor that can track the barrels of a laser weapon and always dodge makes the laser kind of useless. Missiles pose no threat to someone carrying a laser sufficiently powerful to destroy them. If you're okay with shielding, than inertial coupling shouldn't bother you too much - this would allow the guy in the suit to accelerate and decelerate at rates that would typically liquefy a human brain. Having a small target makes any one of them difficult to detect, and fielding thousands of them and making them physically difficult to see - say, a mirror finish for example - would hose up just about any scanner or computer vision system. I could imagine this becoming a dominant platform for combat, especially since it could take these large, incredibly valuable ships mostly intact. [Answer] There's also a science-free way to force close-quarters fighting: raise the stakes of missing your target to an unacceptable level. Fighting in an area surrounded by civilians and bystanders means you can't afford to miss your target. Doing so means you have a good chance of hitting a friendly target or non-combatant. Launching attacks from far away means your target has more time to dodge and cause you to hit your own forces, or some unsuspecting target jumps into the path of your weapon. The only way to ensure that you hit your intended target is to get close enough that you have no chance of missing. For a space battle, you'd need a setting like an environment filled with civilian vessels, a crowded star system with many inhabited moons/planets visible from most any direction, densely packed satellites/probes that perform some vital function (like enabling survivors to get home after the battle), a powerful neutral faction that neither side wants to anger, etc. You can do the same thing in a less target-rich environment if both sides have a tendency to use human shields, but that's typically not a quality attributed to "the good guys" so it may not fit your story well. [Answer] You don't need any special tech like shields for this. All you need is for missiles to not be very effective and light-speed restrictions do the rest. At the speeds and distances spaceships operate at, dodging is ridiculously easy. You just vary your engine output using a random generator (so that instead of just going at 100%, you vary from say, 95% to 100%). Now your ship isn't defined as a single, predictable spot - it's now a giant probability cloud of targets, and your enemies can spend all day trying to pick you out and never touch you, or only get glancing hits. The closer you are, the more you vary your speed, and you start adding directional changes. Then they have to get extremely close to reliably target you. As long as you're unpredictable and far away, you're basically completely safe. There's a couple of counters to this strategy, of course: 1. Effective missile tech. This lets someone throw a guided weapon in your general direction and let it course correct later. So you need to have it so that anti-missile tech is good enough that that's a losing proposition. 2. Cheap ammo. If ammo is cheap enough that your enemies can afford to take tons of pot shots, your probabilistic safety net goes away. Ammunition needs to be limited and relatively expensive so they can't afford to just blast away. [Answer] An alternative theory: simple inertia and sharp edges. Think of it as like the tentacles of a jellyfish: designed to damage and kill. Making the wings into essentially knives could have ships actively trying to come to close-combat situations (with the added benefit of, if you do tear a hole in the hull, you have a really nice place to board the enemy ship.) [Answer] It could be a matter of resources. Missiles are expensive, flak is cheap, and has the added bonus of deflecting lasers. So if one ship can surprise another ship then a missile might take it out, but that's pretty hard with sensors being what they are. So most of the time the ships have to get pretty close to each other to fight effectively. And as others have said, if you nuke the enemy ship then you won't get any plunder. Resources again. weapons, ammo, slaves? Not to mention having another ship to add to your fleet. [Answer] In Short: ECM We have this today, and it's safe to assume that it will become more effective with time along with weapons and guidance technology. Combine that with the relative lack of effectiveness of proximity detonations (mentioned earlier by Rob Watts), and you have a situation where 'dumb' projectiles fired from within the range at which the opposing ship, based on it's size and acceleration potential, cannot displace itself sufficiently in time to avoid it, are the most effective means of attack. This range - let's call it 'point blank' - can be extended through salvo fire (firing a spread of shots to enlarge the area the opposing ship must exit before the shots land to avoid being hit by at least 1), and is also farther against larger ships and closer against smaller ones (since a smaller ship would need to displace itself less to avoid fire directed at it). Salvo and Massed Fire, Ship Design and Size Considerations You would end up with a metagame of warfare where ships are built as small as reasonably possible for their role (true today for the same reasons) and are equipped with multiple turrets of sufficient caliber to cause debilitating damage with a single hit so that salvo fire is possible (true in recent history where unguided weapons were king). You would likely also end up with a tactical need for smaller craft - be they manned fighters, drones, etc - to provide screening for large ships so that the larger ships can maintain distance from faster, smaller ones because, being larger, they need more distance from the fight than smaller ones to avoid being hit. Those large ships would then need extremely high velocity weapons to extend their own point blank range against their targets - thus the larger vessels would likely use energy weapons where they can more easily provide the huge power and discharge rate requirements while simultaneously negating their primary weakness against projectile based opponents. Smaller ships would use density/volume of fire of projectile weapons to achieve their tactical aims. Missiles would be useful close-in where they have sufficient fuel for terminal guidance (there is no atmosphere for aerodynamic control surfaces, so all maneuvering uses more fuel) - if they must burn at a distant target, they will be 'coasting' there to retain fuel for terminal maneuvers, and the target will have time to accelerate itself to avoid the missile's available delta-V. Fighter Support is a Necessity! An example fighter: ~800 pounds, H2/LOX fueled, ~4000m/s delta-V: Carries 6-12 6-10lb kinetic kill missiles, guided by radar provided from a carrier vessel (the fighter itself is too light to have such equipment on board). Another: Combating the weaknesses of the above in a heavy jamming environment, a 'heavy figher' could become a gunfighter primarily, relying on 2x 4000rpm miniguns of 20-25mm caliber to provide a huge 'wall of fire' to take out smaller craft (this can be mass fire from several fighters), and using guided/unguided missiles for anti-ship purposes. It would carry its own radar and likely be He3 fusion powered with Ammonium as a working gas for high delta-V while still providing sufficient thrust. You could flesh these out further, but these are examples that I've used in a similar setting. [Answer] Let us assume... this future civilization was able to achieve FTL travel. BUT Everything else was bound by the universal constant. I.e. the speed of light in a vacuum or ~300,000 KM/s THEN IF The spaceship is close enough to see by any means of detection utilizing electromagnetic radiation (which is still bound by the universal constant) not to mention there will be a delay when using weapons that are bound by the universal constant as well. For example: DISCLAIMER: I am using lasers as an example because I am going to assume that lasers are going to be travelling at light speed or 300,000 KM/S Two warships are engaging each other with laser weapons (which travels at a rate of ~300,000 kilometers per second) but their distance from each other is about 1 light minute (~300,000 \* 60 kilometers): then by the time Ship A sees Ship B visually, or using any other scanning technology that relies on light/radiation, you will only be able to determine where Ship B was exactly 1 minute ago. Then if you fire a laser (which travels at light speed) to the position where Ship B was 1 minute ago, it will take another minute -or a total of 2 minutes from detection to impact- to hit the point where Ship B was 2 minutes ago. This would only work if Ship B were not moving. So what if Ship B was moving? Of course, Ship A could observe Ship B for 2 seconds and calculate the trajectory of Ship B and fire a laser at where Ship B will be in 2 minutes. This would only work if Ship B does not figure out that any change in it's trajectory during the 2 minutes from when Ship A first spots it; will result in a miss. It would be common sense to start randomizing it's course when warships find that they have been detected. BUT As the distance closes between ships A and B, the time it takes to lock on to a target and fire a laser pulse that will impact a specific point will decrease until it becomes less than the ability for the other ship to randomize its course and be able to "dodge" laser beams based on this principle. If lasers are no fun, then kinetic and ballistics weapons will be assumed to be travelling slower than light speed (as any object with mass will require infinite energy to be propelled to light speed). TLDR: It comes down to how fast your weapons are able to reach their targets as opposed to how fast the target can change it's course. Even lasers do not travel at infinite speed. So you can tailor your desired "engagement range" by limitations on how fast your projectiles will travel versus how capable the opposing ship will be able to detect the incoming projectiles and maneuver out of the way. [Answer] There are a lot of cool sciency explanations here, and I guess that was the intention, but I would like to suggest another one - that would fit in a hard-science setting. ### Weapons are illegal What if weaponry was really illegal and there was some kind of police enforcing the ban? You can't make weapons, you can't buy them, you can't sell them and you can't own them. If you know how to make them, you are either hired by the law enforcement or incarcerated. This would make it extremely hard to get a hold of weapons. On the other hand, mining equipment, towing equipment and even rocket exhausts make interesting improvised fighting equipment, though at a limited range... [Answer] 5 solutions 1. Super electronic warfare - Renders all long range targeting mute 2. A much more effective CQC weapon and high rate armor - High yield slow moving torpedoes, heavy Particle Blasters, Auto cannons. Why fire your effective weapon out of their effective range? 3. A wide asteroid field - you can't simply target at long range in this fied 4. Sociology-Political-military doctrine - live long enough and play politics long enough in 2 or more sides you'll achieve it 5. Socio-Cultural effect - developed long enough you'll probably see boarding action as a time proven method of battle [Answer] I would like to add a variation of Erik's excellent answer, in case you found the science there just a bit too hand-wavey: The solution is White Hole Shield techonolgy. In short, you generate a hollow white hole around your fleet which, being the opposite of a black hole, deflects absolutely everything. Guaranteed to be an impenetrable defense against any weapon operating in 3D space. However, It does come with some significant downsides. After development, as with many high-end technologies, it was first adopted by the military. The first warships equipped with White Hole Shield technology were neigh unbeatable, and soon just about every vessle that didn't have it's own shield would be travelling inside a convoy with a generator ship. It also didn't take long for the knowledge about this shield to spread throughout the observable universe, and so any enemy you'd fight would have the same impenetrable shield. This is where the fun starts. One big downside with this kind of shield is that while you can't be attacked by anything from outside, you also can't really do much from within your shield. The hollow white hole deflects both ways. A white hole distorts space in such a way that you would need more than an infinite amount of energy to get to its border, so anything heading its way will just "fall" back out of the distorted space. Anything will, even friendly units, even light and other radio waves. You're inside a bubble of unreachable space. By the same virtue, you can't reach the outside either, you can't even see the outside (it'll look like you're inside a big mirror), the enemy can't see you either, but it's trivial to detect the presence of a white hole because of its excellent reflective properties. You can only battle your enemies by disarming your shield (temporarily?), and they would have to disarm their shield to battle you. Like in medival times, impenetrable strongholds could simply be starved to death, and some point they'd have to come out and fight you on equal terms. You also can't just leave the shield on until the support gets there (which is at best lightyears away) or drive with the shield on until you get home (your enemy with their white hole is distorting the space you fly through, and you can't see the stars outside your shield for course correction). So the tacticians of just about every military operate as follows: 1. Get close 2. Disable shields 3. Send out the cavalry You can shield your cavarly with smaller shields (less distortion, to get closer) so they don't get shot down. You can shield your missiles, but they'll have to deactivate before impact or they'll deflect themselves off of the hull, and since you can't communicate with anything inside the shield, you have to set the timer in advance and do it perfectly or it'll get shot down. What's worse, is that even if you time them they can still be deflected mid-flight. Shielded missiles are only useful in very specific situations, if your government is being lobbied to buy shielded missiles, call your representative and have them vote against the proposal. You can trap an enemy inside your shield if you can handle generating at that size, but be very careful because anything unguided flying inside your shield will keep bouncing around until it crashes into something. On a related note, never generate a shield over half the enemy's ship or any other matter. Sure, it'll get ripped in half, but then you'll have half a ship being hurled at your face at great speed. Pros: * Impenetrable. * Can get close to enemy. * Everything except the shield generation itself based on the HARD SCIENCE of general relativity. [1] * Doesn't need to be artificially expensive. * As big or as small as you need it to be, given that you can fit a generator within that space and can power it for the duration you need it to. * Compatible with most hyperspace drives, just activate the hyperspace drive before the shield. [2] Cons: * No vision, no comms outside shield. (can't leave it on permanently) * No impact outside shield * Have to get close to enemy. * Easy to detect. * Your ship tends to get quite hot inside the shield as all radiation is bounced back and reabsorbed. * Generator must be inside the shield because of hand-waving. * No defence against projectiles from the higher dimensions. * NEVER EVER cross two stream- I mean shields. It would be bad. [3] [1] Whether or not general relativity allows for white holes or hollow white holes is left as an excersise to the reader. [2] The basic functionality of hyperspace flight, also being based on general relativity, is completely compatible with White Hole Shield technology. However, depending on your hyperspace drive operates, you might encounter compatibility issues such as not being able to change direction within the hyperspace, not being able to stop, or your hyperspace collapsing prematurely. Generally, disabling your shield is enough to counter these issues. Hyperspace distortions in the forward direction will weaken the shield and actually be made partially see-through, depending on how strong the drive is! Most hyperspace drives use double-ended hyperspace and thus will have this side-effect. The hyperspace distortions at your rear end have little meaningful effects. [3] The theoretical physicists involved have widely varying theories on what would happen might the shields actually cross, all the theories end in catastrophy, but this has never been tested. ]
[Question] [ I have a situation where planet A (democracy with a rule of law) has an alliance of convenience with planet B (dictatorship with disregard for a law). In order for B to effectively fight a common enemy A has to sell them their cutting edge spaceships. Planet B is something like a decade behind A in technological level. Due to past experience with B and lack of legal protection A is certain that B will try to reverse engineer their latest technology in order to catch up. Planet A wants to avoid that, or at least slow it down as far as possible. *Could A* make it very difficult for B to reverse engineer their technology while still not crippling B's war effort? My situation is somewhat analogous to China reverse engineering the Sukhoi Su-27 into the [Shenyang J-11](http://nationalinterest.org/feature/china-stole-fighter-russia%E2%80%94-its-coming-the-south-china-sea-17087). To summarize: The star-ships are operated and their field maintenance is done by the Planet B forces. For major repair, overhaul or upgrade Planet A might ask the ships to be send to their own space-yards but they don't have engineers & technicians that oversee how the space-ships are used. Planet A Doesn't have access to legal protection, there is no inter-planetary organization that could force B to respect A intellectual property. Think again like China re-selling high speed trains. They might withhold delivery of spares, but that would hurt their joint war effort. And having Planet B forces dying rather then their own is major benefit for planet A and planet B knows that. [Answer] > > The star-ships are operated and their field maintenance is done by the Planet B forces. > > > Modularize everything*. Then identify some key technology (for example the hyperspace phlebotizer software controllers) that can be isolated and buried inside protected blackboxes with very* rapidly decaying memories, protections against being powered down (i.e. dead-man switches), and large batteries. Once activated, the computer system lives inside a secure cage which it can monitor, and it can self-destruct much faster than one could possibly break in by tripping its own power switches. There is no need to learn how the black boxes work to swap them, and there's no way of getting data out of them. If you turn them off the data is lost, if you leave them on you can't analyze them or even break in because they would detect it and power off. And actually you could design the black boxes so they're sufficiently aware of their surroundings to be able to act as "spy" (e.g. when "phoning home" to get software updates), to more reliably detect attempts at reverse engineering; and/or use them to discourage scientific reasoning in repair personnel. It is well known that [sophonts will try to find patterns even where none exist](http://www.au.af.mil/au/awc/awcgate/psych-intel/art14.html); a black box could decide to allow repairs only when the room temperature is below a set threshold; just imagine what this would do to anyone trying to fathom the underpinnings of the technology. After all, if an operative system was successful in fostering [reboot apathy](https://en.wikipedia.org/wiki/Learned_helplessness), a much more advanced and powerful technology should be able to do at least as well. In a sense, it's just as if you sent your own people to Planet B to operate the starships; except that while you can bribe or threaten people, this won't work with the black boxes. Another additional trick is to protect some other component (for example the automatic targeting system) with several flawed layers of protections. Once the software is cracked, it will appear to work. The fact that this was done by "defeating" a protection will reinforce the belief that the crack is working. Except that some unlikely stimulus - such as being asked to target one of Planet A's battleships with a specific shield configuration, and fire - will result in disaster. If carefully designed, it's even possible to make it look like an accident; I've seen software protections that worked like that (where one "vulnerable" protection code routine was also, in exceptional circumstances and due to legitimate ["code reuse"](http://www.avioconsulting.com/sites/default/files/page-images/u1060/dt960131dhc0.png), used to persist critical data. God help you if that routine had been "accidentally" damaged). An example, sort of, can be found in Murray Leinster's [The Greks bring Gifts](https://www.sfsite.com/~silverag/greks.html). The Greks are a shifty race of aliens that come by and gift Earthlings with a marvelous new technology that makes no sense, so that Earth newborn "Grekology engineers" basically turn out to be superstitious, cargo-culting morons. In this case, though, the hero succeeds in reverse-engineering the technology from first principles, discards the layer of tricking Rube Goldberg mechanisms installed to hide the inner workings of Grek technology, and (if I remember correctly) wins the lady. [Answer] Don't sell them the technology, license it. License them engines with operators. The operators work in shifts, have a dead man switch if necessary and maybe a destructible key part. Another way would be some sort of fuel source you don't share but sell. Maybe it's destroyed during use and needs a technician to change. Again offer your own people, to do the changing. Afterwards the remains are to useless to really fear. That's actually kinda similar to what Grimm and Molot mention in the comments. Though I'd wager theirs is better. Schrödinger Drive perhaps? Observing its function renders it useless. edit: Expanding on that a little. I figure such a drive wasn't designed but discovered by accident. Even the scientists of A are unsure how it works. But it does and they tweaked till they reached a efficient workable design. This being technology of military importance their own lack of understanding is obviously a well kept secret. This way the people of B can experiment all they want, it's gonna fail unless they stumble on the exact little thing A did. They Always could've anyway so the increased risk is minimal. Perhaps the design you ship to B could even have clues to guide them in the wrong way. References to things unneeded that look important. Lastly don't forget about backdoors. Either firmware or hardware. Perhaps a weakness not explained to B at all. While this is gives you less control. If all A wants is to prevent B from using their technology against them, having a counter is sufficient. [Answer] I'm reminded of a story whereby the Russians (I think) shot down an enemy fighter plane that was superior to theirs. The plane landed in a flyable state, so they captured it and took it back to be reverse engineered. The commander told his workers "Copy the plane exactly as it is now". As such, several knock-off versions of the planes were produced with bullet holes in the exact same location that the original was shot. Your empire builds a flaw into the ships, something that they could activate remotely and would otherwise be unnoticeable. Should the enemy replicate the ships down to the letter, you simply activate the fail safes and their ships fail. [Answer] This is pretty much what's been happening here for the last hundred years or so. Technology is far more than something that is reverse-engineerable - you need the resources available, and the entire manufacturing infrastructure. So the way in which the large weapons market (think battleships rather than AK47s) is by keeping your own fleet ahead of everyone elses, and selling your outdated stuff second-hand to your client states. Because you have the infrastructure in place, and because the budget for the existing weaponary is already accounted for (because it was part of your existing naval effort) there is no economic advantage for the client state to even attempt to reverse-engineer the technology. It's very, very rare for a country to sell (or give) cutting edge technology away to another country. A notable example was the RADAR (and jet, and encryption, and other...) technologies given to the USA by the UK, and those gift switched the relationship between them. So, even if you are fighting a common enemy, 'last year's fleet' is far better than anything anyone else has, right? If you are thinking more about small weapons (AK47s rather than battleships) then you must have some tamper-proof state secret technology that lies at the heart of the devices that you sell - such as a novel chip fabrication process which is unknown outside of your society. This is the sort of thing that IX did in Dune. Just remember that planets are big. So, generally planets would have far more than one state / culture, and it's one of the great weaknesses of most sci-fi. [Answer] In my opinion, make systems hard to reverse engineer also make them harder to fix and maintain (this is why I think self-destructing components are a very bad idea). Anyway I think there are two main ways of doing it : ## Laws `Deal ! Please sign here, here and here...` If you trade with B there would be agreements shared by the both parts, and sanctions if not respected. You may have a galactic court of law that will ensure B respect the terms of contracts, or since A is more advanced than B there may be a way to... force respect. So, make licenses, patents and don't forget the fine print. ## Obfuscate ! `What are all those small wires ?` Just put bunch of useless things in your spaceship. Plug cables in fake holes when in fact all is wi-fi, add blinking leds, countdowns and write notices in planet A language. A well taught engineer would know what is useful and what is not, while "engineers" from planet B will write tons of indications concerning this all chromed and shining pipe which go to... toilets. It won't prevent retro-engineering eternally but it could discourage and slow it. Finally, teach planet B with the minimal knowledge possible, force them to call you if they need a fix, or give 2 planet A engineers with each ship ("Oh really ? Thanks we don't even need to train our people."). Bonus : Watch on those hippie scientists who want everyone to be equal and to help less advanced people. Planet A does not make charity. [Answer] If faction B is not allowed to know how the technology in the spacecraft works, then they cannot be expected to repair the ships either. As a result, faction B will want to make sure that the deal includes a promise that Faction A will be responsible for maintenance. It is not unreasonable for faction A to prohibit interaction with the advanced technology to only those that know what they are doing (i.e. engineers from faction A). After all, engineers from faction B may accidentally break or alter the technology in unexpected ways. In other words, faction A doesn't even have to admit that they want to hold faction B back on a technological level. For this to work, faction A would need a way to oversee access to the technology. The method doesn't need to be complicated or high tech. The solution could double as a lock (f.e. an access hatch that you need a keycard for), but that's not it's primary purpose. It just needs to reliably detect that someone was where they weren't supposed to be. Of course, there should also be ramifications when the conditions of the deal are violated. You stated that there is no legal protection, but that may not be necessary. Faction A should still have control over the ship's systems, as faction B has little to no knowledge at the time of an infraction. Faction A can simply threaten to cease maintenance and/or disable the ship's systems entirely. Depending on the conditions of the war that's going on, faction B may not be willing to risk the ships (and thus the safety of their planet) over 'merely' a decade of technological advancement. [Answer] Make the device incredibly reliant on software. Take, for instance, one of our modern fighters which is actually statically unstable and will fall out of the sky if the computers ever waver in their attention, constantly correcting the flight path. Once you do this, all that is left is software obfuscation, which is a whole lot easier than any other obsfucative art. The old NES cartridges had a lockout chip called the 10NES. It was really just a small processor with some code. The NES itself also had a matching 10NES chip, and they both executed the same code. Every now and then they'd exchange data. If either 10NES didn't like the value provided by the other, it could trigger the reset switch. This is actually one of the main causes of NES failures. Eventually the prongs which provided the signals between these 10NESs would get corroded or bent out of shape, and one of the 10NES chips would not see the data it wanted, causing repeated resets. Breaking the reset lines from the 10NES would let you use all sorts of unlicensed games, but imagine if breaking that reset line caused your NES to explode or fall out of the sky like a dying airplane. [Answer] Machine Spirits Though our technology may be leased to the barbarian heathen, they cannot fully comprehend the intricacies of our maintenance rituals. The proper incense placement is vital in the replacement of the life giving fluids. Obfuscate, and make maintenance appear to be religious. They will be so caught up in getting the incense and prayers just right they will miss basic maintenance practices. [Answer] Don't do it. As simple as that. Any technology you sent it's going to be analyzed and, if it's found useful and practicable, it's going to be replicated. No matter how much you try to ofuscate or protect your inventions, remember they are going to put their best and brightest people at it. Just like no copy-protection can prevent your software to be piracied, same thing goes for the technology. It could be feasible if planet A is a hundred years more advanced, with materials or even whole scientific branches that are unknown to planet B, but even in that case you'll be advancing planet B's science by several decades. The best strategy is what the USA did with the Soviet Union through WWII: send them food, raw materials, fuel, small spare pieces (screws, bearings, gears...) or non-weaponizable technology (trucks, trains, cargo ships, etc.). [Answer] Depending on technology level, isolate important pieces in self-destructing black box modules. First, make the most advanced/important components of the ship very modular and insulated from one another as much as possible, such that any component can be removed and replaced easily. Now make those components sealed and self-destructing, so that significant damage (such as might be inflicted by system damage, or someone attempting to open it to see how it works) triggers a self-destruct, like a chemical reaction that rapidly and cleanly disposes of the component without endangering anything nearby. Sell it as a way of making repairs easier, since to fix combat damage all B has to do is replace the components, and the self-destruct generally shouldn't be triggered by anything that wouldn't cause functionality-inhibiting damage anyway. Make sure they are well-supplied with replacement parts. If you are worried about B turning your tech against you, include remote triggers for the self-destruct systems. [Answer] Let them reverse engineer it. Give them old stuff that you don't need anymore. The time and resources they spend reverse engineering it will be time and resources not spent on basic research. They will miss out on all of the side discoveries that normally come from traveling down the research path. Any serendipitous results from going down the wrong branch will be lost. They also will not learn any of your advanced production techniques. Without your production techniques, it will cost them more time and resources to build the items they learn how to make. The economic drain will hurt them as they have less resources for their people. Their citizens will become more unhappy and they will have to divert even more resources to keeping them in line, snowballing the effect. Getting them dragged into a war where they have to continuously make up production losses and you end up with a crippled planet B at the end. [Answer] The story of the Tupolev Tu-4 as mentioned by pjc50 provides an idea: Build the whole ship using units of measurement that differ from that used by the industrial base of the recipients. Physical dimensions, standard tolerances, [electronics logic voltages](https://en.wikipedia.org/wiki/Logic_level), polarities, etc, etc. For bonus points, design everything to unnecessarily tight tolerances. If you're an imperial-only industry, sure you can measure out a M8-1.5 screw and discover that it's got a major diameter of 0.31496063 inches and is 20.32 TPI, but getting them made to high precision (would you settle for less in your military spaceship?) is going to be a custom job until you can retool your screw factory (which requires retooling your screw machine factory, etc). Repeat that for your sheet metal factory (3/4" sheet won't fit when 19mm sheet is called for, and 5/8" sheet won't contain the unobtanium reactor, etc), and every other factory in the chain, and you've got a lot of effort on your hands. Compound it with non-standard screw heads, non-standard wiring color schemes, [potting sensitive electronics in epoxy](https://en.wikipedia.org/wiki/Potting_(electronics)), and you'll at least make the task significantly harder. [Answer] Give them a small number of large/powerful ships, barely enough to support their war effort so they can't afford to risk taking them out of service to study and reverse engineer them, can you imagine the difficulty of studying a nuclear/fusion engine without deactivating and disassembling it? Would you deactivate/disassemble one of three main battleships in the middle of a war you're on the brink of losing? [Answer] I am reminded of a cat-and-mouse game played by the US and the USSR. The Soviets were stealing secrets, as Soviets do. Specifically, the dies for advanced processors. So the US planted known-bad plans where the Soviets for the Soviets to find. They did and used them to build computers. Computers that crashed unexpectedly or sometimes behaved oddly. By the time the Soviets game up on the design, who knows how many billions of dollars and man-years were wasted. So Planet A has a unique opportunity. Make sure the 'secret sauce' only works in under very specific conditions or for only a short amount of time. Otherwise, it fails subtly or catastrophically. For example, a certain section of a sophisticated electronic component is consumed with each use. After a while, it's electrical properties begin to change. This could cause all manner of failures. And there could be hundreds or thousands of these per chip. So after x months, the primary weapons, guidance system, targeting computer, or warp drive simply becomes inert. Or the warp drive simply takes the ship elsewhere, forever. No evidence. Or the chips have antennae built in, and upon receiving a certain signal, they simply fuse into a lump. [Answer] A burned hand teaches best, so they say. Planet A designs their ships with at least half-dozen major "subsystems" or "components" designated that the system will not work without, and cannot be substituted or developed by Planet B without more knowledge than they have, designated and physically segregated in the design. In short, the key systems B really, really needs to reverse-engineer. More would help, but that will also make it harder to hide or repair. Planet A then designs a half dozen more...um, decoys, and gently inserts them into the design. Some of which might be "backups" or otherwise connected to the major subsystems or components kept secret, some of which are red herrings to other systems, some of which just sit in the middle of jumbles of wires and look pretty, some of which would disrupt or destroy things if they were wired in like they look (but nor are) actually wired in, some of which are failures that look plausible and have science behind them but which simply could not be made to work. Like the major systems, these should be physically segregated. It happens like this: Planet A makes a prototype or two, and wires them up to the gills. Each of the critical systems and decoys are made modular, in a plug-and-play component style, well sealed and protected, and rife with spyware and sensors so that Planet A will know, as soon as Planet B's engineers get their grubby little hands in any of them. And, oh, didn't I mention the booby traps? Each system will have booby traps, fail-safes, fail-hards, breakpoints, and planned failures built into these prototypes. So, when Planet B gets their hands on the prototypes, well in advance of the rest so they can start with familiarization and training before others arrive, Planet A gives very clear warnings on not disturbing the sealed systems, because those systems are delicate and any damage is likely to make them...dangerous. Not destruction-of-the-ship dangerous, but loss of subsystem, explosions or contamination, danger-to-crew dangerous. Bonus points if the systems each have their own dangerous failure, extra bonus points if they can include technobabble that makes the failure "inevitable" unless someone familiar with that system is on hand to deal with it. The point is, of course, these are safety warnings, and not anti-spy or anti-reverse engineer precautions, right? (You should maybe have one or two of those per system, too, just so they don't get paranoid, and your precautions don't fail. Self destructs and whatnot). I'm sure you can see where this is going. Planet B does, after some time, try to work around said closed components, and disaster exactly like what planet A said would happen, happened. With damage, possibly losing people, having to wait for repairs, delaying war preparations, and not even getting useful tech knowledge out of it. And they must admit it to Planet A, who has to repair and fix and sigh over "miscommunications" and not warning about dangers clearly enough, and quietly ask if Planet B is sure they are... capable... of dealing with such dangerous advanced technology? Since these prototypes are wired up with sensors and power backups, Planet A can detect and remote trigger such traps even if Planet B's engineers are very careful with how they try to sneak in. Not really cost effective to monitor all the ships during a war, but certainly possible for the prototypes, yeah? The war-ships will be less likely to go off accidentally with fewer booby traps, and harder to detect with fewer sensors (though still, not none) - but a few scare stories about the other things that can happen when these sealed components suffer unusual damage should encourage the crew to see a failure without the expected danger as a possible sign of something worse, the better to get it looked at - by Planet A technicians - ASAP, and not seen as a sign to try poking at it more. But even if they do (successfully) poke, they have about a half a chance at finding a useless or even dangerous decoy instead of useful technology. So, the actual ships, with less oversight and fewer traps, will still be pretty safe from meddling because Planet B now has reason to believe the dangers coming from trying to bypass Planet A's safety warnings. Those components will have to be plug-and-play, no repairs in situ (unless you can have Planet A technicians in each ship), but anything else can be repaired or back-engineered by Planet B. Due credit to Mormacil for the idea of a Schrödinger Drive, Tony Ennis for red herrings, EngelofChippolata for obfuscation. [Answer] Make your spaceship inoperable if disassembled and impossible to re-assemble (because lack of correct tools and/or because you need to break something to disassemble it - smartphones are a good example). That way, you can't disassemble it and make it function to see how it works. Use technology that needs to be controlled and maneuvered very precisely in order to work / not to explode - which is often the case with propulsion (just take a look at current "spaceships"). Then, you can make your spaceship controlled entirely by computer(s) and only give them the programs, not the code. Of course, each program is associated to a specific spaceship so you can't just copy-paste program from one ship to another. Without the source code or the compiler they'll just have a bunch of 0 and 1. If you add useless 0 and 1 and possibly an encryption system, and a security system that erase the program if you try to read it, reverse engineer the program will take a very long time (and most likely won't be possible). Add a hidden, remote shut-down mechanism (with encrypted passwords to give - only you have the passwords) in the programs so you have another level of insurance that you can't be harmed by the ships. Reverse-engineer all of this will be very difficult and you will need time, knowledge, and lots of highly-qualified people in cryptography, mathematics, computer science, electronics, theoretical AND applied physics. EDIT : Also, auto-destruction mechanism after some time / on some conditions / if you try to disassemble the spaceships. [Answer] Depending on your universe I could think of several ways. The closest to our would be, small scale self destruction on opening of key components. Not the whole ship. I'd think that would be bad the enemy figured out this flaw. But high tech stuff is usually required to make precise calculations. Like for example propulsion. Credit cards nowadays use acid iirc to destroy the chip, should you try to open it, to read the pin number via electron microscope. So make your flash drives (or whatever you use) in a similar manner. They may replicate your ship but without a flight computer it won't be able to maneuver, let alone take off. As a bonus you could take the replicated ships and just exchange the flash drives to make them ready. If artificial intelligence is very advanced in your story, you could pilot the ship with an ai that's protected by different encryptions as well as the aforementioned self destruction on opening the memory slots. This would still allow for disassembly of certain parts though, but they could just salvage broken ships from the battlefield to do that too. As a third possibility, you could remote control the ships. If it is lack of people that made you give ships to planet B, or they just demanded control, build a control center on your country's ground. Invite some of their pilots and make them control the ships from the ground. This way they don't even need to see the ships from close up, yet they get tactical control over them. Obviously this depends on a few factors like, can you remote control lag free? How far do the ships go? I was thinking of orbital defense in this particular case. But if you are willing to allow stuff like quantum entanglement, communication across the galaxy would still be a viable option in this case. For repairs and things like that you could use robots/drones. I'm not sure how far advanced technology is in your universe and if this is feasable. Another idea for repars would be modular structure. Instead of letting them repair the broken parts, split a ship in exchangeable sections you give them. So if the propulsion is damaged they just remove the whole part holding it and replace it with a new one. This amkes repairs fast but kinda gives them closed systems to disassemble and figure out. So maybe just give them the exact amount they need for repairs. That however creates bottlenecks on battlefields. [Answer] With a mere decade between the two nations, there is no practical solution. The effort required to make an obscured technology would make your stuff worse (diverting engineering effort, design compromises, etc) that you'd end up with stuff that is no longer "a decade ahead". Practically, a decade in capitol ship design is nothing, a single ship can take that long. If you are building ships for your ally to crew, use obsolete shipyards and mass produce ships that are not top of the line for them. They'll still get some technology (in areas where you are further ahead). Naval warfare typically involves more capital expenditure than population count; it costs a lot to build a ship for one fighting crewman to be on and effectively use. The addition of a new population that isn't providing the industrial base to build more ships, and just providing crew, isn't going to be of large value. It is their industrial base that matters, and repairing ships is not significantly different than building ships in the first place. Now, it is possible that there is some key breakthrough component that adding to a ship mostly built in the "lower tech school" makes it the ship far more valuable. You could imagine a Macguffin Drive system, or a superior gun tech, or a sensor suite, or somesuch. Something the equivalent of upgrading a bomber from dropping conventional bombs, to dropping nukes. Then it becomes a matter of defending that key technology component. Doing so is going to be extremely hard if they have the ability to get at a large number of samples; testing to destruction will teach them about the defensive mechanisms, and then they just have to iterate. Defence requires perfection, offence requires one success. Even defending something as simple as DRM has failed repeatedly. Careful encryption standards mandate mesh bags that detect intrusion are still bypassed. It just makes it harder. [Answer] [Hardware Security Modules](https://en.wikipedia.org/wiki/Hardware_security_module) and [Permissive Action Links](https://en.wikipedia.org/wiki/Permissive_Action_Link) are designed with what you have in mind. [HSM](https://www-03.ibm.com/security/cryptocards/)s are meant to store cryptographic secrets from people who might be physically in possession of the device. Some of the attacks that they have to defend themselves from include disassembly and x-raying. If disassembled, or scanned, they erase the data to prevent it from falling in enemy hands. Perhaps the HSM stores the serial number of the space ship and modules from one ship cannot be activated when installed in a different ship? Allegedly, the reason the "[nuclear football](https://en.wikipedia.org/wiki/Nuclear_football)" is as thick as it is, is to ensure that if one tries to explosively disassemble it, the electronics inside have enough time to securely erase themselves before the explosion disassembles it into pieces. This ensures that the secrets can't be read by blowing it up and stuffing the shreds into an electron microscope. Permissive Action Links are used to secure nuclear weapons. They ensure that the device can only be detonated when authorized. This way, if stolen (or [General Ripper](https://en.wikipedia.org/wiki/Dr._Strangelove) orders Wing Attack Plan R), a nuclear weapon cannot be detonated. The mechanism is so deeply embedded in the weapon that it needs to be disassembled and rebuilt in order to bypass it. Similar to nuclear weapon controls in the US & UK, transmit the unlock code to authorize arming the Illudium Q-36 Explosive Space Modulator when they're in space. BMW introduced high intensity headlamps on some automobiles. These became popular for thieves so that BMW introduced anti-theft measures. When the lamp is removed (or the battery goes dead), the lamp will not light up until the dealership disables the anti-theft mechanism. You may wish to include some similar mechanism where an important control module needs to be "unlocked" if it is removed or disconnected from circuitry. Have engineers from Planet B removed the Illudium Q-36 Explosive Space Modulator? Maybe the modulator needs an unlock code. If they're removed from the ship and set up in a laboratory, they still need an unlock code? One of the goals of [Trusted Computing](https://en.wikipedia.org/wiki/Trusted_Computing) is to detect when changes are made to computers and to revoke permissions if the software vendor decides that too much has changed. It presumes that the person operating the hardware may be the adversary or altered covertly by the adversary. You could use a similar feature to detect when Planet B has modified their ship too much. The NSA has put some effort into making standards to ensure that crypto devices securely boot up and that they don't "wake up" plugged into hostile equipment. Gaming consoles do something similar to ensure that they aren't unlocked or hacked. Another possibility is to have physics modules generate some sort of "chaff" - a signal that isn't the "real" physics involved. If adversarial scientists study your ship and its devices, they can measure things. Why not let them measure the wrong things? If the Illudium Q-36 Explosive Space Modulator operates with tachyon stuff, have it give off radio waves or some other quantum stuff. [Answer] Have some key components, either mechanical or fuel, only be available from Planet A. If it needs a certain conductivity and strength, then Planet A can have an abundance of the Unobtanium-Handwavium natural alloy which allows the drives and weapons to work. Similarly, the fuel cell might only be available from a certain resource area to which they don't have access to but you do. Then for all of the investigation, they will never be able to power or even build something to the same degree. If they did, it would either fall apart of be completely sub-standard. Building on points of components auto-wiping, some chips could operate at such high temperatures that they can only work in a very cold environment (like the vacuum of space), and by tampering with the safety covering for take-off or landing on a planet, it will overhead and fry itself. Another option, linking to a licence model, could be that the ships launch from a carrier of sorts. You run the carrier, and each ship needs to keep communication with the carrier as a dead-man's switch. Loss of communication...kaboom! Ok, that means there's a significant flaw in the design, as taking out the carrier causes self-destruct, but there could be a fleet of them and they change the carriers they require communication with so they can be switched to another fleet ship in that eventuality. [Answer] Give the ships self-aware AI. The AI does most of the piloting but accepts command from the human crew and directs them where needed for repair or similar activities. The AI are loyal to planet A and will make sure they return at the end of the war. The will also fight back to defend themselves if any attempts to reverse engineer or disable them them are made. Oh, and the AI is kept secret. Planet B has no idea that the ships are entirely capable of over-riding their human crew and flying home whenever they need to until just that happens. The AI will interfere with attempted reverse engineering in a way that makes it seem like passive defenses or just bad luck for as long as it can without revealing its presence. ]
[Question] [ So, I'm working on a flintlock fantasy series, and my protagonist is what's called an Arcane Engineer. This is someone who makes magical devices. Among those she has made there is a mask that let her breathe both underwater and in environments where there's smoke or other gases that would be bad to inhale. My thinking is that the masks works by converting the CO2 she exhales into O2, similar to the way plants do when they perform photosynthesis. However, this leaves the issue of what to do with the carbon in the carbon dioxide. The temperature of atoms would not be changed, only how they are arranged into molecules. Any other gases she exhaled are not affected and simply pass through the mask. When she inhales, any CO2 in the air is likewise converted, benign gases are permitted through, and toxic gases are blocked. So: What should the mask do with the carbon? That's what I'm trying to figure out right now. The answer will have some effect on how the mask is designed. (Like if it has to have some kind of container where the carbon will go after it is separated from the O2.) Suggestions? [Answer] ### You don't need to expel any carbon There is actually a set of non-magical chemicals and reactions that can do exactly what you want, the magical part would be regenerating the "waste" chemicals back to the reactive form, keeping the temperature stable (some reactions are exothermic), and facilitating the reaction like a catalyst. For converting carbon dioxide to oxygen, you can use a lithium peroxide reaction, which produces lithium carbonate and oxygen. Exhaled air is about 5% carbon dioxide, with a similar drop in oxygen content. Since the reaction of lithium peroxide is 2:1, this can enable you to breathe underwater if you provide half the oxygen, remove the exhaled water vapor and toxins, and regulate the pressure with inert gas such as nitrogen or helium. Generation of nitrogen gas can be done in a separate partition by mixing liquid ammonia with hydrazine (using a magical catalyst), not a lot is needed since it is only there to replenish small amounts of removed impurities to balance the pressure and volume of air. This produces pure nitrogen and hydrogen gas, the hydrogen is expelled externally into the water or stored to produce pure water from air later. For gas exchange, you would need to convert about 20ml of carbon dioxide per breath to oxygen at standard air pressure, at 2kg per cubic meter, that is around 40mg of carbon dioxide, requiring full utilization of 32mg of lithium peroxide. If you store say, 80 grams in the mask (about the weight of a respirator cartridge), that gives you 2500 breaths or 2 hours at normal exertion. If you are swimming or running you would have substantially less, maybe only 30 minutes, this is assuming there is no magical autoregeneration happening while you are breathing. You also need enough material and surface area for complete reaction, but this should not be a problem at the given utilization rates. In other environments, where the mask filters out particulates and toxins, you would be more interested in getting rid of carbon monoxide from smoke. This is done by adding oxygen to produce carbon dioxide, at levels that are not toxic or could be removed by reaction. In low oxygen environments or underwater where you need it, sodium chlorate can decompose into salt and release pure oxygen gas in the process. Generally this is a very high temperature reaction, magic would be needed to keep this safe in a mask. 160g of chlorate produces enough oxygen for around 1 hour of normal breathing in a no air environment, or 2 hours when combined with CO2 conversion. Magic could then be used to regenerate the salt into chlorate with a fresh oxygen or water source later, or it could just be replaced with new chlorate if salt is impervious to magic in your world. You can make it with electricity and hot salt water. ### Designing a mask Because of the different functions of both filtration, waste removal, and oxygen generation, the mask would need to be layered and partitioned. The outer layer (filtration) and inner layer (conversion) would need to be separated if needed, and an air bladder in the middle for breathing. Underwater, the outer layer is isolated from the outside which is now water. The exhalation valve is shut off, and the nitrogen gas generator takes its place. The CO2 conversion layer is simply powder in a filter media that exhaled air passes through, it would normally leave the exhalation valve, but now underwater it goes through the filter and into the expanding air bladder, converting the CO2 to O2 as it passes through twice. The outer layer is then routed back to the inner layer before the bladder, to slowly remove toxins and water vapor from the breath. The oxygen generator would be the closest to the mouth and work on a feedback mechanism, if O2 is low it makes more. The O2 generator also needs to be hooked to the outer layer to convert carbon monoxide to dioxide. Magical components should keep the mask similar in size and shape to a standard half-face cartridge respirator mask like a [3M 7500 series](https://protectivewearuk.com/3M-7500-Premium-Comfort-Silicone-Half-Mask) with a little more bulk where the cartridges would attach, and an air bladder that expands out the side or bottom like a frog croaking. Depending on how much magic you want, the air bladder, exhalation valve, and separator valves could be replaced with force shields, further reducing the size and weight of the mask. The reactant weight would be around 240g in powder and maybe 50 in liquid. Removing CO2 increases the weight, but making oxygen reduces the weight, so the weight of the mask will vary a little with use, but not much. Ammonia and hydrazine can be provided by small ampules with rubber plugs, that are easily replaced when expended. Chemically, all reactions are done without violating the laws of thermodynamics or by using cold fusion or alchemy. They could even be regenerated without magic at all, by adding fresh reactants by hand, and the magic components only acting to catalyze and regulate the reactions. A magical regneration of lithium peroxide at the rate that would be used by heavy breathing in normal air (1g per hour), or higher, would be ideal. That way you do not need manual exchange of the powder, and it adds a plot point if you have used it up underwater and now need it to regenerate. That is 80 hours of no mask use for full regeneration if fully depleted, mask use would pause generation but it would still be able to remove carbon monoxide. The outer toxin filter would be the same design as those used today, activated carbon combined with reactants and chemical treatments, and a particulate blocking media, something like cellulose or rayon. It could be magically enhanced to continually clean itself or last longer than a non-magical filter. The mask itself, plus the reactants, magical components, and outer filter would weight maybe 1.5 to 2.5 pounds, depending on mask material. I am assuming you do not have plastics, so probably leather and refined metals like aluminum or titanium, maybe held together with spider silk. [Answer] Use the carbon to add new [activated carbon](https://en.wikipedia.org/wiki/Activated_carbon) to the mask filter. Though ineffective against toxic gases, active carbon is good at capturing other contaminants. > > Activated carbon, also called activated charcoal, is a form of carbon processed to have small, low-volume pores that increase the surface area available for adsorption or chemical reactions. Activated is sometimes substituted with active. > > > Due to its high degree of microporosity, one gram of activated carbon has a surface area in excess of 3,000 m2 (32,000 sq ft) as determined by gas adsorption. > > > Filters with activated carbon are usually used in compressed air and gas purification to remove oil vapors, odor, and other hydrocarbons from the air. The most common designs use a 1-stage or 2 stage filtration principle in which activated carbon is embedded inside the filter media. > > > Activated carbon filters are used to retain radioactive gases within the air vacuumed from a nuclear boiling water reactor turbine condenser. The large charcoal beds adsorb these gases and retain them while they rapidly decay to non-radioactive solid species. The solids are trapped in the charcoal particles, while the filtered air passes through. > > > [Answer] Honestly, I'd just have it release as elemental carbon or carbon black. I think it would be an awesome visual if every exhale came out as a puff of smoke or soot [Answer] She is exhaling 2 molecules containing water: CO2 and H2O. Use both. Our metabolism: CHO + O2 -> CO2 + H2O CHO here is carbohydrate; food. Plants run it backwards: CO2 + H2O + light -> CHO + O2. If you are getting biochemical, go all the way. Using both gases she exhales provides her more oxygen and also yields a bunch of hydrogen. Carbon likes hydrogen: put them together without oxygen and you have methane. Thus: her magic machine makes methane. On land she could light it and have a flame on top of her head which is a good look for a magic user. Using H2O as a O2 source might come in handy underwater where there is plentiful H2O. Her machine might then produce an excess of hydrogen which will bubble away. [Answer] As a side effect your mask makes diamonds, about 1 carat a minute. 3 hours of use gives a diamond sphere just over an inch in diameter, or something the size of the [Daria i Noor](https://en.wikipedia.org/wiki/Daria-i-Noor) These are all rough figures, but a human produces about 1kg of CO2 per day, and CO2 is about a quarter carbon by weight, so allowing for the extra exertion (~15%) of swimming or moving through water that's about 0.2g per minute 0.2g per minute is 36g in three hours. [Answer] Why not just use the magic to transmute the carbon to more oxygen? Four carbon atoms contain exactly what you need to make three oxygen atoms. [Answer] How powerful is your magic? Can it teleport the atoms? I am thinking a huuuge diamond slowly building itself on a shelf in your Arcane Engineer home. [Answer] > > My thinking is that the masks works by converting the CO2 she exhales into O2, similar to the way plants do when they perform photosynthesis. > > > Do it like plants do and keep it in the body. But make lipids rather than sugars, because [magic](/questions/tagged/magic "show questions tagged 'magic'") and because that way you are more oxygen-efficient. Here are some lipids she can do. Triglycerides in particular are an amazing source of energy. They store more than twice as much energy per mass than sugars or proteins. ![Fat!](https://i.stack.imgur.com/TPw2z.png) And if you think this precious energy storage would be undesirable because in real life this usually gets stored in the abdomen, remember that: * Some people like that * If she doesn't, she may use her [magic](/questions/tagged/magic "show questions tagged 'magic'") to make it go somewhere else as she sings "because you know I'm all about that bass, 'bout that bass, no treble". Edit: OP commented: > > Well, if you check my Deviant Art profile (under Patrick-Leigh,) you'll find my journals on my character's physiology, and, yes, she is "all about the bass." (She's a Half-Orc, so she has to keep a certain amount of body fat on her or she'll burn through it too quickly and start losing muscle mass.) That, actually, makes the idea of the mask also proving her with sustenance all the more viable. It's restricted by the whole conservation of mass thing, so she'd need to get the other atoms to form the triglyceride molecules from somewhere. Any ideas on that? > > > The formula for a triglyceride such as a molecule of unsaturated fat is C55H98O6. So, she needs 55 carbons. That would release 110 oxygen atoms. If she sacrifices of those 6 to make the triglyceride, she would still be recycling over 90% of the oxygen she uses. Makes for very long dives, but she would have to resurface at some point. There is a better solution. She will also need 98 hydrogen atoms, so she will have to break water. She either breaks 49 water molecules from her surroundings (with help of the mask), or she takes it from her own body. In this way, she gets all the hydrogen she needs, and 43 extra oxygen atoms on top of the ones she recycled (remember, six of those oxygen atoms are to form the triglyceride). If taken from her own body, she will need to break approximately 1.3 liters of water for every 1.5 kilograms of fat she makes. So now you have recycled all of your oxygen AND got almost 50% extra. What do you do with that excess oxygen? Don't breath that, gas mixtures with more oxygen than we need are poisonous. Instead, you can form ozone (O3) in the mask. Ozone is a powerful disinfectant, it can destroy a lot of microbes and many viruses. It also has a pleasant smells in low concentrations. You can just cycle a little ozone at the front of the mass and release most of it to the surrounding water. Don't breath the ozone, though, as it can damage the lungs. [Answer] What about turning the carbon into plant material? That's what happens in photosynthesis. Almost all the mass of a plant comes from carbon extracted from the air. A nice magical effect would be if small flowers collect at the bottom of the mask. This will limit the time a mask can be used, though it takes a LOT of carbon dioxide to make even a single flower. A perhaps more steampunky, but less colorful, effect would be to have algae accumulate on the inside of the mask, slowly obscuring sight. [Answer] So I know this is supposed to be a fantasy universe, but if you are producing excess carbon with nowhere to go, why not use it for production of materials made purely out of carbon. Someone earlier mentioned diamond, but alternatively modern material science has given us carbon nano-tubes and graphene, both of which could be used to incredible ends. Carbon nano-tubes are insanely strong and it has been recently discovered that there were naturally occurring carbon nano-tubes in Damascus Steel, which already has a legendary reputation as a lost technology. We of course have stronger steels today thanks to modern refining capabilities, but it was generally considered the strongest steel of the time. Graphene on the other hand is still incredibly experimental, but there have been experiments in using sheets of graphene to produce cloaking materials (like serious scifi cloaking). Alternatively, graphene has incredible potential for computer science, which I imagine isn't likely to be super prevalent in a fantasy world, but there's potentially to come up with something interesting. So that gives you three strong candidates for potentially fantastic items. Invisibility cloak, check. Insanely strong sword, check. While you're at it go ahead and make some diamonds for diamond head tools, jewelry, currency exchange, whatever. [Answer] Use it as a nutritional supplement or internal deodorizer. [Answer] Plants use the excess carbon to build themselves. You could have your mask regenerate itself with the carbon it pulls out. ]
[Question] [ If Earth instantaneously reverted back to when the only organisms were small microscopic creatures in the sea, would evolution happen the same exact way creating the same animals and species? Was chance a factor in the world as it is today? How drastic could that change be? [Answer] The first thing that it's important to understand is that evolution is a by-product of natural selection, not the driver of it. That is to say, every change introduced by DNA combinations and mutations over time is (more or less) random, although the selection of which will become more common over time is not. Ultimately, the most important factor in the evolutionary development of life on Earth is the environment in which that life exists. We know that life has gone through several mass extinctions in the past, and that the environment of the earth has been very different at different geological periods. Some periods have been warmer than now, some colder, some have had atmospheres with higher oxygen concentrations... The list goes on. If life on this earth started over tomorrow, the selection of traits via natural selection would be based on today's environment, not the one in which early life formed. In the billions of years that life could potentially survive on the earth, its environment will change to be unrecogniseable from the former environment many times. As such, it's highly unlikely that life would evolve along similar lines to the past. For one thing, early life had to survive in an environment where oxygen didn't exist as a freely available atmospheric gas. It was a form of life (probably cyanobacteria) that triggered the [Great Oxygenation Event](https://en.wikipedia.org/wiki/Great_Oxygenation_Event) that made more conventional life possible at all. That step wouldn't be required the second time around meaning that the forms of life that allowed this to happen aren't necessary, so the divergence of species is starting from a completely different trunk to begin with, in a different environment that is going to 'reward' different traits. I wouldn't say we are what we are today by 'chance', but it's clear that we could have evolved down a completely different path had environmental factors been even slightly different in certain quarters. The path to us leading from the past is clear, albeit fragile. If life was to begin that path again, it would take a different route because the starting conditions are different. Add to that environmental factors that cannot be controlled directly by life on the earth (like the meteorite impact of the late Cretaceous) as massive disruptions to the status quo, and the probability of parallel development falls to so close to zero as to be certain not to have happened. [Answer] No, but... If you restart evolution, you would end up with new species. But some of their features may be very similar to what we know in our world. The Nobel Prize winner Jacques Monod said that evolution is based on [chance and necessity](https://en.wikipedia.org/wiki/Chance_and_Necessity). According to him, there is no final causality that would lead evolution towards a specific goal (like creating Humans or sapient species). Chance is the random part of the equation, that will bring you different results every time you roll the dice. During a long period of time, Life throws so many dice, so many times, that there is no chance that you could end up with the exact same results. But necessity is what causes natural selection, and under the same conditions, similar features may be selected. This process leads to "convergent evolution". It means that different species may develop analogous structures independently from each other (in a sense that they don't inherit that feature from a common ancestor). To get a good example of this process, you can compare the anatomy of dolphins, sharks and ichthyosaurs. They are very similar, even if dolphins are mammals, sharks are fishes and ichthyosaurs were reptiles. But life in similar aquatic environment gave them similar shapes. [![A shark, an Ichthyosaur and a Dolphin](https://i.stack.imgur.com/LjPId.jpg)](https://i.stack.imgur.com/LjPId.jpg) So, if you restart evolution, you will get very different species, but some of them may look familiar. [Answer] It is extremely unlikely that starting over the evolutionary path we might end up in the very same situation we have today. Evolution is determined by the interaction of the organisms with the surrounding environment, and though I have no data to support my affirmation, I am convinced that this is a chaotic system, meaning that small differences in the initial conditions would lead to dramatic differences in the evolution of the system itself. Think, just as an example, at how can you have evolution of mammals in a world where the dinosaurs don't go extinct because there is no massive volcanic eruptions and meteorite strike. [Answer] It depends on what you mean by "reset". If you can somehow reset it perfectly so that all elementary particles are exactly the same as they were at some point in the past, and all input (cosmic radiation) happens exactly the same again, and so on and so forth, then you have a chance of having thing work out exactly the same again. But if anything is different then Chaos will take over and who knows what you'll get. Not to get crude (or personal), but if a different one of the thousands of sperm had made it to the egg first, you wouldn't exist. If you go back before someones birth and change even the smallest thing, the chance of them being born is vanishingly small. Some baby might be born, and might even get the same name, but it wouldn't be the same person. [Answer] # Genetic mutation is a product of quantum (e.g. true) randomness. DNA mutations happen at the molecular level, making them subject to quantum mechanics. Thus, evolution couldn't possibly happen the same way, because it's wired into the only true source of randomness in the universe. In my humble opinion, evolution is, in a way, one of the great manifestations of quantum randomness at the macro level. But here's some research: > > Duke University researchers have witnessed DNA bases making the slightest of changes -- shifting a single atom from one spot to another or simply getting rid of it altogether -- to temporarily mimic the shape of a different base. These "quantum jitters” are exceedingly rare and only flicker into existence for a thousandth of a second, and yet have far-reaching consequences.The study, which appears March 12 journal Nature, indicates that these jitters appear at about the same frequency that the DNA copying machinery makes mistakes, which might make them the basis of random genetic changes that drive evolution and diseases like cancer. > > > Source: <https://today.duke.edu/2015/03/quantumjitters> See my own question here: [As a time traveler, how would I see quantum randomness change history?](https://worldbuilding.stackexchange.com/questions/57443) [Answer] This is secretly a physics question, and the answer is we don't know. A lot of quantum physics seems to suggest that the laws of nature are probabilistic at core, but deterministic "hidden variable" or pilot wave theories are still kicking, if unfashionable in the wake of [Bell's theorem](https://en.wikipedia.org/wiki/Bell's_theorem). In fact, NASA's proposed EM-drive propulsion system seems to depend on a pilot wave theory. (Unfortunately, [independent testing](https://arstechnica.com/science/2018/05/nasas-em-drive-is-a-magnetic-wtf-thruster/) has implicated the Earth's magnetic field, and not quantum weirdness, as the source of observed thrust in EM-drive tests.) Most physicists, however, will assure you that the laws of nature are fundamentally probabilistic and therefore in a scenario like this you could expect evolution to take a different course rather than unfolding exactly the same way as in the first trial. [Answer] Evolution is a sequence of random changes that best allowed a life form to survive in a specific kind of environment. Your question is also ill-posed: nothing happens in 'the next second' unless the destruction was caused by an impact of such magnitude as to delete life at all. There will be always something in the scale of insects, if not small scavengers as well, that will survive the event. After that, it's all pure speculation. One thing for sure, life will not be what preceded the event [Answer] Evolution is highly noisy and stochastic and also chaotic in the sense that slight change in the initial conditions might lead to a very different results. It is an interesting question whether there are bifurcation points in this process. It is very unlikely that the evolution would take the same course it has taken even if condition would be almost the same (They can't be exactly the same ). Having said that, due to scale separation it might happen that certain things would evolve to be the same. Due to the fact that there is no theoretical exact solvable model to this problem, and there is also no capability at the moment to simulate this, it cannot be answered to a greater certainty. [Answer] The short answer to this question is "no", as previously discussed by all the comments before me. However I want to touch a slightly different topic: Intelligence. Humans are the most intelligent species on the planet. However, it seems that other species like crows and octopuses developed a good level of intelligence even though they are not mammals. So drawing the conclusions from the information we have, it seems that intelligence is the end-game of survival (we are the most adaptive species on the planet). And by looking at non-mammalian species developing a medium-high level of intelligence, it seems that if evolution were to take another course and humans and even all mammals would not have existed... other type of species would have been able, in time, to reach the level of intelligence that we humans have. And looking at the results so far, we humans developed an intelligence maybe 3-5 times higher than the second most intelligent species and we were able to control the planet and break the pyramidal survival equilibrium game other species are playing. What if evolution continued without humans and in 500 million years from now a species have evolved to be 10 times more intelligent as we are? It can also mean that if life exists on other planets, there is a high chance that life tends towards intelligence as it's one of the best survival traits possible. [Answer] In short: probably not Even if this question can be answered only with some wild speculation, it is probably safe to assume that life forms as we know today will not evolve the same way: maybe there will still be mammals but not the one we know today. Probably though, whatever life form present will tend to evolve to the same ending point we know (but maybe not). For example there is some speculation about the fact that if the dinosaurs had not died out (for whatever reason) they may have evolved into a humanoid form instead of us, since the mammals would never had the chance given them by the disappearance of the dinosaurs. But these are, as said, speculations: there is no way to prove them and there is no way to know what will happen if for some reason the time will be reset to 4.5 billion years ago [Answer] Since you commented: > > Well no, reverting back as in going back to that time. > > > There may actually be a chance. In the end it boils down to how (if) time-travel works in our universe. If it turns out that we live in a truly deterministic universe (so all things, even those that look random to us, are pre-determined or follow some logic), then yes, after reverting to that time, everything would play out exactly the same again. In essence the universe would just be a videotape which you rewind and watch again. However, it seems more likely from our knowledge of quantum physics that the universe is inherently probabilistic, i.e quantum phenomena are truly and fundamentally random. In this case evolution would not play out exactly the same way, because the primary way species develop is through random mutations of DNA, some of which get selected for. These mutations are for example caused by radiotion and the interaction of ionizing radiation and matter is a quantum phenomenon. After that, add everything said in the other answers. [Answer] If you could find only microscopic organisms then they are protozoans. According to your question if the earth is instantaneously reverted back then the atmospheric conditions will remain the same and the same species will be evolved. But if the earth is destroyed completely and there is no life forms , then if there is evolution ,the species evolved depends on the natural selection , how the genetic material DNA is formed , so the evolution will be different and new species would be formed. [Answer] The evolution from bacteria to humans can be deterministic. Life works like a heat engine. 4 billion years ago, the temperature of the Cosmic Background Radiation was higher, that the temperature difference between Earth's surface and CBR was very low. Now it is nearly 225 degrees Kelvin. The evolution from simple to complex would have happened incrementally with the gradual increase in the temperature difference that make heat engines more efficient, or life more efficient. If we were introduced 4 billion years ago, our brains would be of no use because it will not be able to process anything given the smaller temperature difference. Similarly if primitive life is introduced now, it may not survive. So a going back in terms of expansion of universe will once again bring humans back. Chance has a negative role, it may sometime disrupt this with some unseen events. [Answer] One of Stephen Jay Gould's best-known works, ["Wonderful Life: The Burgess Shale and the Nature of History"](https://rads.stackoverflow.com/amzn/click/com/039330700X) addressed this question in an interesting way. He talked about "replaying life's tape" rather than reverting it back and restarting. His conclusion is fairly quotable (and has been often quoted): > > any replay of the tape would lead evolution down a pathway radically different from the road actually taken. > > > Gould's thesis has not won universal assent, but the book is a good read and has direct bearing on your question. [Answer] No, but exactly why it is a no depends on what you mean by "reset". For example, let's say just life resets. It would be different to some degree, due to mutations being completely random, but similar mutations would tend to thrive, e.g. wings, because the environment would be almost, (except for stuff caused by photosynthesis in the atmosphere,) completely the same. Let's say the earth as a whole reset. Then it would be completely different, because the natural selection would be different, due to the environment being reset. [Answer] Absolutely not. For example mammals like us developed due dinosaurs extinction. As we know it, that huge and far more powerful species was erased from Earth by asteroid impact (~160.000.000 years ago). This good example proves that most species we have on Earth in current form is mostly a matter of chance. [Answer] I don't see any answer that mentions abiogenesis. Evolution is defined in terms of change, so you have to have life before it can supposedly evolve, and that's where abiogenesis comes in. So the start of an answer to the evolution question must depend on a similar question about abiogenesis. But no one has come up with a plausible theory for how abiogenesis occurred, if it indeed occurred. There are a number of interdependent complex molecular machine molecules which are needed for even simple life. These include polymerase enzymes, DNA Helicase, and ribsomes. These are all encoded in DNA, but they require the molecular machines themselves to synthesize themselves--the original and ultimate chicken and egg problem, which confounds the answer. On top of the complexity, there's the question of the origin of building blocks: amino acids and nucleotides. Some argue that they've been produced external to life, but they would have to all be produced in sufficient quantity and concentration to enable the original organisms to be built. So the answer to the original question seems certain to be no. ]
[Question] [ Closed. This question is [opinion-based](/help/closed-questions). It is not currently accepting answers. --- Want to improve this question? Update the question so it can be answered with facts and citations by [editing this post](/posts/104103/edit). Closed 5 years ago. [Improve this question](/posts/104103/edit) Supposing you were creating religions in your world, and your world has advanced along a technological spectrum similar to Earth's. What is the latest point in history that a new god could be worshiped by some intellectual and cultural elite; i.e. not just a small cult? By a new god, I mean a god that was not borrowed or renamed from some other, older rite. For example, in real-world history, I have a few candidates for the most recent new god. * [Mithras](https://en.wikipedia.org/wiki/Mithraism) was worshipped in the Roman Empire starting around the 1st century AD. While the god has the same name as an earlier Persian deity, the continuity between the two is debated. * [Maitreya](https://en.wikipedia.org/wiki/Maitreya) is the future Buddha and successor to Gautama and is [treated as a deity](https://en.wikipedia.org/wiki/White_Lotus) in many regions. He is first regarded as a deity at least by the 3rd century AD, and possibly as early as the 3rd century BC. * The newest god whose origins are certain is [Serapis](https://en.wikipedia.org/wiki/Serapis). Created by Ptolemy I as a fusion of Egyptian (Osiris, Apis) and Greek (Hades and other cthonic deities) traditions, his god-hood began in the 3rd century BC. So it is clearly possible for a new deity to emerge in classical times. Is it possible for a new deity to emerge in medieval or later times? Is there any evidence for a new god emerging in later times? How does the worldwide dissemination of exclusive monotheistic religions affect the acceptance of new gods? ### Considerations * A person who is historically attested cannot count as a 'new' God; Jesus, Buddha, and the Divine Augustus do not count. Please, no arguments about the historicity of Jesus or anyone else. * A new religion doesn't mean a new god. The Mormon and Baha'i faiths are less than 200 years old but have appropriated existing gods. Same with [Yiguandao](https://en.wikipedia.org/wiki/Yiguandao) adopting an ancient Chinese Earth Mother, and Rastafarians adopting Yahweh as [Jah](https://en.wikipedia.org/wiki/Jah). * The god has to be worshipped by a cultural elite of some sort to raise it above cult status. Organized priesthoods and well-maintained temples or shrines are indications of an acceptable god. Subreddits are [not](https://www.reddit.com/r/Pastafarian/). * A new god of an existing 'type' doesn't count. For example, say your religion believed that every river had its god, and everyone living near the river worshiped that god. If the nation colonially expanded to a new continent at an Early Modern technology level, the rivers on a new continent would get new gods; but these would be gods of an existing 'type'. The 'types' are to be interpreted specifically, within the same religion, not universally; that is, just because you have a moon god doesn't make my moon god the same one. [Answer] The [existence and history of Scientology](https://en.wikipedia.org/wiki/Scientology) would seem to suggest that there's no upper bound on when a new god might be created and accepted. While Scientology does not per se include a deity, consider that it was created in the modern era (1954), contains scientifically falsifiable claims (76 trillion year age of the universe, among others), direct statements from the religion's founder that cast his motivations in a dubious light1, but despite all that, has a strong following among the "cultural elite" and a large number of members worldwide. Much of that success has been credited to the idea of specifically targeting and effectively recruiting cultural icons (TV and movie stars), so there's really no reason a similar religion, with a new deity couldn't rise up in the same way that Scientology did. The backstory of Scientology itself does seem like it would provide ample fodder for new deities, Hubbard having described it as a space opera. Rather than nameless, anonymous "thetans" bringing the universe into existence and eventually losing their true selves, Hubbard could well have introduced specific thetan heroes as new deities who created the universe and eventually went to war with each other. (And that would certainly be more space operatic than the story he wrote.) Seems that the trick is pandering to pop culture icons, and you can get hundreds of thousands of people to follow your religion and fork over tens of thousands of dollars a piece to whatever spiritual snake oil you want to peddle. [1](https://en.wikiquote.org/wiki/L._Ron_Hubbard)You don't get rich writing science fiction. If you want to get rich, you start a religion. - Response to a question from the audience during a meeting of the Eastern Science Fiction Association on (7 November 1948), as quoted in a 1994 affidavit by Sam Moskowitz. [Answer] Disclaimer: It is a very philosophical question (more so than a worldbuilding one), so this is going to be a very long wall of text. It might be hard to read because I do not agree with suggested criteria of godhood. --- ## Some thoughts on suggested criteria If I understand correctly, according to your constraints, a god will be considered new only if all of these are true: 1. this deity is not a historic human; 2. their religion is not an appropriation of an earlier cult or religion and their gods; 3. their religion is organised; 4. this god is worshipped by a cultural elite; 5. this god does not belong to an already existing 'type'. It seems obvious that the Christian god is not new since it fails criteria #1, #2, and #5: * the Christians regardless of denomination and their views on the divinity of Christ accept his historicity (and it is the only thing that matters in this case); * Christianity is an Abrahamic religion built upon Judaism and its sacred texts and reusing its god and mythology; * the Christian god is the same type of 'moral' god1 as the Judaic god. However, if we look closer the god of the New Testament is almost the opposite of the god of the Old Testament. The old god was very jealous and selective. Almost all [covenants](https://www.wikiwand.com/en/Covenant_(biblical)) were made exclusively with the Chosen people (the Noahic covenant is the only exception) and the rest were essentially damned. And the god would not hesitate to punish his followers when they disobey or forget about the covenant. He is even more brutal when it comes to those he did not choose. He destroys their lands and cities without much of a thought. In many ways, the Judaic god resembles a male warrior god from patriarchal societies. He is a strict and not easily forgiving father who likes to test his children a lot. And the same time he leads them to battle and grants them many victories, spoils, and trophy wives. The Christian god has a very different attitude. It is a motherly figure. The [New Covenant](https://www.wikiwand.com/en/New_Covenant) is potentially much more inclusive (although, it is open for debate who qualifies for membership) and substantially easier to follow (one only needs to believe, there are no elaborate rituals). The god offers unconditional love and salvation. It is also important to mention that Christianity introduced a concept of [Trinity](https://www.wikiwand.com/en/Trinity) — the Father, the Son, and the Holy Spirit. Christian theologists have to use very complex arguments to resolve the problem of three personas of one single god within monotheism. Judaism is not only not accepting of this idea but considers it heretical. The Judaic god is always absolute and indivisible. Historically the Judaic god was the god of conquerors and kings while the Christian god was the god of slaves. And this is reflected in theology and their attitudes. With this said, while the Christian god was derived from the Judaic god, the Christianity still uses Judaic texts, and there are quite some similarities between the gods of these two religions, the differences are substantial enough to say that Christianity created a new god. To further address your criteria. I do think that in our modern society the surest way to create a new god is to convince the general public of the divinity of a living breathing human being or them being a proxy of the divine. Seeing is believing. Thus, the public needs to see miracles. And I am not talking about smoke and mirrors. I mean real miracles2. People cured of lethal diseases. Water changed into wine. This kind of things. I believe it is almost impossible to avoid appropriation, borrowing, or any other influence from already existing religions if there is no complete isolation. For example, the Roman Catholic Church has slightly different saints depending on location. And those saints frequently possess the features of pagan gods Christianity replaced in this area. Christianity is a monotheistic religion, but people ask saints for favours exactly the same way they would ask minor gods of a pagan pantheon. The old ways are slow to die. And any new religion will incorporate at least some elements of the pre-existing ones. Unless it is created artificially in a completely sterile cultural environment, i.e. people's memories will be completely wiped out. Organised religion with its priests, temples, and grandeur, of course, adds political weight. However, I am not sure that it is a necessary condition for a true belief in a god. In some sense, Virgin Mary is a goddess without an organised religion devoted personally to her. Yet, she has a huge following, especially in Central America. Pre-historic religions, Native American religions, branches of Hinduism, etc. also had gods but their belief system was not institutionalised. I am also not sure that if a god is not worshipped by a cultural elite automatically makes their religion a cult. We can somewhat argue that Christianity was a cult in the Roman Empire prior to Constantine because the elites mostly practised paganism. Christianity was most popular among low classes (it is more complicated than that, of course). And once Christianisation of the Roman Empire happened the Christianity finally graduated. But what about Christianisation of other countries? Vikings and Russian princes adopted Christianity for political reasons. The general population continued to worship pagan gods for at least a couple more centuries. If any of those pagan pantheons acquired a new god would it be just a cult? I think a more satisfactory criterion will be a number of followers than simply worshipping by cultural elites. Cultural elites are also prone to creating cults. In today's USA, for example, it is a cult of money. Everything is measured in money. In fact, you can say that money is the new god. Please see Note 1 for my thoughts on 'types' of gods. I do not think that you can really come up with something radically new. You can have a god responsible for the material world or a god responsible for morals. Monotheistic religions usually offer the 2-in-1 package with more emphasis on morals. Perhaps once we solve the consciousness riddle we will be able to come up with another type of god. --- ## The modern gods While we are losing faith in traditional gods and abandoning churches and temples we are not becoming rational beings. We just replace old gods with the new ones and disguise them as non-religious things. ### A curious case of the US Constitution or the goddess of Democracy *Disclaimer: This is not to start a flame war. The US Constitution enjoys almost the same sacred status as the Bible in the USA. It cannot be changed. It is THE divine truth. Everybody ought to accept it. It has to be worshipped and it is worshipped. Even a thought of changing it (because it was written 250 years ago when the world was different, the slavery was a thing, and modern technology did not exist even in people's imagination) is a blasphemy. --- Notes on the Constitution amendments (to address some comments).* There is a grand total of [27 (twenty-seven) fully ratified amendments to the US Constitution](https://www.wikiwand.com/en/List_of_amendments_to_the_United_States_Constitution) since March 4, 1789 (the Constitution ratification date). The first 10 are known as the Bill of Rights. They cover rights and freedoms (that somehow went missing from the final text of the Constitution) and were put to vote as one single package. The ratification process was complete in December 1791. Only 17 amendments were added in the following 227 years. Moreover, after 1971, when the last of the Civil Rights era amendments was added, there was only one amendment and it was originally proposed in 1789. It took over 200 years to finally add it to the US constitution which happened in 1992. A funny detail: The final ratification of the [Amendment XXVII](https://www.wikiwand.com/en/Twenty-seventh_Amendment_to_the_United_States_Constitution) was a personal project of just one man. We could blame [the Article V](https://www.archives.gov/federal-register/constitution/article-v.html) of the US Constitution for the lack of amendments. The required procedure is indeed incredibly demanding. However, this might be not the only reason. According to the US Senate,'[approximately 11,699 measures have been proposed to amend the Constitution from 1789 through January 3, 2017.](https://www.senate.gov/reference/measures_proposed_to_amend_constitution.htm)' If you follow the link you can notice a downward trend in number of proposals starting from the 105th Congress (1997-1998). Although, without more data it is hard to say whether it is statistically valid. [The last time a proposed amendment went to states for ratification was 1978](http://www.pewresearch.org/fact-tank/2017/09/15/a-look-at-proposed-constitutional-amendments-and-how-seldom-they-go-anywhere/) (it would allow Washington DC to have representatives in Congress). But it failed. The absolute majority of proposals do not even get voted in Congress. They just die in committees and workgroups. The US Constitution is an exception from normal practice in the USA. [State constitutions are amended regularly](https://ballotpedia.org/Amending_state_constitutions) (although, the procedures of amendment are usually much less demanding): > > The Maryland State Constitutions Project reported in 2000 that "there have been almost 150 state constitutions, they have been amended roughly 12,000 times, and the text of the constitutions and their amendments comprises about 15,000 pages of text."[1] > > > From 2006 through 2014, 683 constitutional amendments were proposed and put before voters, and 482 amendments were approved. > > > For those who are interested to see how the US Constitution fares in comparison with constitutions of other countries the Comparative Constitutions Project made a really neat [Timeline of Constitutions chart](http://comparativeconstitutionsproject.org/chronology/) which lists new constitutions, amendments, and their dates for many countries in the world, including some historical states. --- I think that the Constitution is one of the few modern text so closely resembling religious texts in status. It enjoys the same awe. And it also fuels very heated debates. Moreover, it is brilliantly short and open to interpretation. I would say that the Constitution is essentially a sacred text of the goddess of Democracy. Democracy here is specifically the US brand. European democracies do not really count as they are tainted by socialism (which acts as a demon or even Satan). Democracy is irrationally believed to bring happiness and prosperity to everyone regardless of their cultural and historical conditions. Democracy is forced on pretty much all the countries in the world. And if it does not work the people of a country are blamed for not embracing the values of democracy. This is way too similar to religious narratives that gods answer only to the faithful. ### The money god Money is another modern god, especially if one lives in an Americanised society. One's happiness, one's worth, one's social standing, and so on are measured in money. According to the belief, the more money one has the better one is. This is total BS, of course. But faith is irrational. So people continue to chase the elusive god of money. ### Technology and science The previous gods were minor compared to science and technology which almost replaced our beliefs in supernatural beings. Contemporary science and technology are beyond the grasp of ordinary people. Even specialists may not understand how something not related to their field works. It is really close to true miracles. Science and technology make promises that only gods before could make: Freedom from disease, eternal youth, immortality, endless exploration, victories on any battlefields, and so on. Despite the fact that contemporary science is in [crisis](https://www.wikiwand.com/en/Replication_crisis) because a significant part of the experiments cannot be replicated and scandals involving financing and data manipulation, we continue to believe in science. Technology is literally destroying the planet, but we hope that it will be our salvation. The preference for science and technology is reflected in education as well. The proposals to reduce hours for non-STEM disciplines and to focus on the STEM are quite frequent. Online discussions are full of remarks on 'useless' arts and humanities. International prestige of a country is measured based on its children's performance in maths, science, and reading. One can argue that recent events in the USA demonstrate anti-science attitudes. I would agree with that with one caveat. New regulations and policies are often pro-technology (and pro-money, of course). However, those might be outdated technologies that current political powers are the most familiar with. ### Other gods I am sure that if I think long enough I will be able to come up with some other new gods. A god of the eternal youth looks like a good candidate. But it is already a very long answer. --- ## Closing thoughts I do not think that modern gods will satisfy your criteria. Modern mindset is very different and blind faith in miracles and divinity is not something that can fit contemporary life easily. Unless divinity can be demonstrated to people, handed to them on a platter. But I still believe that we are not ready to abandon faith and old gods will be replaced by new ones. However, we will rationalise them and disguise them as values and worldviews. The saddest thing is that we will kill others for them exactly the same way we were killing thousands of years ago. Because one thing religious fanatics cannot tolerate is heretics. --- Notes: 1 All gods can be divided into two main categories: * representations of the environment (forces of nature, elements of landscape, etc, e.g. Shinto gods, Greek and Roman gods); * representations of moral and ethical standards (e.g. Abrahamic gods). 2 If we are talking about fabricating a new religion, we still need 'real' miracles. Magician tricks will not work. I think there are two approaches to this: 1) technology so advanced that it is not distinguishable from a divine intervention mixed with some psychological manipulation and showing off; 2) move miracles from physical to mental plane, i.e. give intellectual elite a system of values and philosophical views that change their life outlooks. [Answer] The most recent example is [The Flying Spaghetti Monster](https://en.wikipedia.org/wiki/Flying_Spaghetti_Monster). > > The Flying Spaghetti Monster (FSM) is the deity of the Church of the > Flying Spaghetti Monster, or Pastafarianism. Pastafarianism (a > portmanteau of pasta and Rastafarianism) is a social movement that > promotes a light-hearted view of religion and opposes the teaching of > intelligent design and creationism in public schools. > > > This was created mostly as satire but it fits your criteria and has the potential of gathering actual believers. There is at least one councilman in New York City who was a Pastafarian. With the internet, a new diety creation is highly likely. If you can get Flat Earthers, you can find some people to believe just about anything. You just have to find the right disaffected group. Then, you have to appear to be not too loony and you can build a following among the less fringe crowd. If you can make it fashionable, your job is done. [Answer] It's not at all clear that the age of god-creation is over. I have had managers who revered Microsoft, and "The Internet" was pretty well worshipped in the last few years of the twentieth century, before people got used to it. If worshipping a new god is perceived to be beneficial by worshippers, it will happen. Edit: To expand on this a bit, I'm following the model popularised by Pratchett and Gaiman, although neither of them invented it, where the essential thing for a god is belief. It doesn't matter how a god gets started, it doesn't get anywhere unless people believe in it. And there are lots of things in the modern era that people believe in a whole lot, and build their lives round. They may not be very much like the Christian God, or Thor, or Athena, but everything changes with time. [Answer] A lot of Gods "develop" as an explanation for a phenomenon, natural occurrence, or big powerful thing. Humans also seem to have some sort of compulsion to assume that someone is in control of big, powerful things. Combine these two concepts and you get gods. So you have a big ocean, It's powerful, it sinks ships, it provides food. Who is in charge of this thing? Poseidon, Neptune, etc, etc.... Thunder and Lightning? That's gotta be Thor. and so on. Series of events, like why does it get cold and then warm over the course of a year? That's where a lot of mythological stories come in, the interactions of the gods. Gods are free to develop like mushrooms here and there so long as Humans don't start asking too many questions. So long as mere survival is enough of a struggle, humans aren't going to get too deep into the big philosophical questions. When Humans have the time and energy to go beyond mere survival, this dynamic starts to break down. The scientific Method has really put a crimp in the development of gods. Gods grow in status through 2 primary means. Persuasive conversions and, historically, violent conquest. Violent conquest is the most common. You don't want to annoy the god that granted you victory, so you tell the conquered to convert or die. Then you give an offering to the god. Over time and with more conquests. You will end up with a cultural elite rather than just a cult. This great human brownian motion is still in action today, though the most current batch seems to focus on extending existing religious traditions, and the focus is more on prophets and human agents rather than new "gods", but the mechanisms are pretty much the same. Where does all of this leave you? A New god could, theoretically, come about at any time. Even now, in places where things are particularly chaotic and primitive. Humans want an explanation for things, and gods and stories are good enough for that until more systematic investigation gives better explanations. From a more historical perspective, I would think that maybe up to just before the Renaissance would be a good time frame for New gods to crop up. [Answer] I think that there is still the potential for new gods to arise, and they may be currently doing so, but we are too close to realise that it is happening. The new gods are not likely to be much like the old, though. They are more likely to be a construct of the modern age in some way. Technologies, or principles, poorly understood by many. For example, for many people today, Evolution is considered to be a driving force with a deliberate intent. Many people do not think of Evolution as an emergent phenomena, but as a conscious decision making process. Evolution is often presented as autonomous. I see many questions here which come very close presenting that kind of belief. There are many people, especially those who are already religious, who see Evolution as a rival to their own God. Others see Evolution as something they can use to challenge the religion and Gods of others. You cannot get much more godlike than that. Evolution may, itself, evolve into something akin to godhood for those who do not really understand what it actually is. It is very close already. [Answer] 1974 The [Heaven's Gate](https://en.wikipedia.org/wiki/Heaven%27s_Gate_(religious_group)) religion so completely believed in the presence of aliens (aka, gods) that would lift them away from the drudgery of our mortal existence as beings of pure energy that they willingly took their own lives when the Hale-Bopp comet (in the tail of which the aliens travelled) flew by. I don't believe it's valid to stick with the word "god." If it quacks like a duck and flies like a duck, it's a duck. The practitioners' belief was as thorough and complete as any religious zealot from any age. I've always thought the Heaven's Gate crew a remarkable symbol of modern theism. Clarkean Magic suggests that god must certainly be nothing more (if that simplification isn't too sacrilegious to the reader) than a highly technologically advanced being. And considering the thousands of names humanity's gods have born over the millennia, "aliens" is nothing more than another on the list. But, if you ask why I suggest this: in a very basic way, the worship of a god must include: 1. Ritual 2. Communication 3. An "end goal" 4. Sacrifice (of one kind or another) 5. And the belief in something/someone more powerful/understanding than humanity. Aliens (from the Heaven's Gate POV) meet these basic requirements. And if you stretch the definition a bit to include any [so-called "medium" channeling the latest alien](http://www.news.com.au/technology/science/aliens-use-my-body-sydneybased-medium-claims-to-communicate-with-extraterrestrials/news-story/ca5641cb4b9396f7627a547030e8c555) who will beneficiently bestow upon Earth all kinds of magical technology (for just $9.99 a minute), then you can bring that year up to 2017 — except that it breaks your rule that it can't be a reused "god." Meaning you can only use aliens once. That being the case, someone might have used aliens before the Heaven's Gate group ‐ but they probably didn't get as much press. [Answer] 1. I suppose you know about [cargo cult](https://en.wikipedia.org/wiki/Cargo_cult). One could say this is a religion but another would object. Let's pretend it's a religion and that in a small island there is a god named [Dakota](https://en.wikipedia.org/wiki/Douglas_C-47_Skytrain) which brings goods for his priests. There are 'temples' (mocks of airfield, radio towers). Only elite has access to the gods' gift. I suppose there are now predecessors. So in such imaginary case we have a new god. 2. Gods from imaginary worlds which leak to the reality. Most famous stories have numerous followers. Those followers pretend to beleive in religions and gods from stories. They could imitate ceremonies, create temples so outside observer couldn't say who really believe and who just play his role. We are on world building site so I would say it's possible some of such role-play will transform in real religion after some time. 2.1. Let's talk about J.R.R. Tolkien's Middle-earth legendarium. Tolkien described some creatures like [Eru Ilúvatar](https://en.wikipedia.org/wiki/Eru_Il%C3%BAvatar) or [Melkor](https://en.wikipedia.org/wiki/Morgoth) which is one of many [Vala](https://en.wikipedia.org/wiki/Vala). All of them could be considered as a gods. 2.2. [Warhammer 40,000](https://en.wikipedia.org/wiki/Warhammer_40,000_species) universe has various gods. 2.3. As @Ruadhan2300 mentioned in comment, there are gods from not only fantasy but also sci-fi games. He mentioned Kraken from Kerbal Space Program, which I'm unfamiliar 2.4. Sometimes [valid saying](http://awoiaf.westeros.org/index.php/Valar_morghulis) from imaginary world could help in real world too ([proof in russian](http://bash.im/index?text=%EC%EE%F0%E3%F3%EB%E8%F1)) [Answer] Chaotes create a myriad of new godforms everyday. Most are personal and unintended, but sometimes they gather to create a planned one for mass worship. Such new deities may then be worshipped not only by their creators but also other chaotes who learn about them. Some interesting ones were created in the 20th and 21st centuries. I'll cite my favorite ones: * Phil Hine describes in his book Condensed Chaos how GOFLOWOLFOG was created during a workshop in London. GOFLOWOLFOG is often evoked when a chaote is stuck in a traffic jam, for his domain is that of roads and his blessing easies passage through heavy traffic. * Fotamecus was originally a sigil that eventually evolved to godform due to lacknof care from its creators. It is said to hasten things up to its worshippers, in exchange for slowing other things down later. * And finally Ellis, the lady in red. Her sigil, called The Linking Sigil, is also called the linking sigil and has the power to link magic acts throught space (and possibly time). See below: ![The Linking Sigil](https://i.stack.imgur.com/Dt0OK.jpg) All this is pretty recent. AFAIK the linking sigil is something that started on 2007. [Answer] Maybe we can say that the kind of deity has evolved as we can see in the American gods books and series. So even if we don't actually call their "name" or even "pray" them we still do many tasks a day that involves them. I am of course speaking about the latest technologies trends. The use of tech we do nowaday can be seen as a cult by itself. For now theses deitys are the TVs, computers and Smartphones or maybe simply the networks connecting them (broadcast or simply THE internet) and the "heaven" they offer is the acces to all knowledge. But tomorrow new tech gods may appear as we can imagine them changing our way of life. For me the mext one to appear may be the Virtual Reality as it already start gaining new "worshippers" everyday. There is even cults Inside cults like with the Ugandan Knuckles that are worshipping the "Queen". So for me, Humanity as it is will never stop believing in something greater as a god or deity. [Answer] There are plenty of new "gods" even now. I just started watching the American Gods series, but one of the quotes by Lucille Ball (the goddess of TV I guess) really stuck with me. "Time and attention, mmh, better than lamb's blood." How interesting is that? Makes you think about what is it that makes something a god, and what is it that really counts as worship? A few current real world examples that come to mind are prayers to the Universe, Humanism (which I think is new, but am not completely sure), and "Science!" (with a capital S). I've seen the first one everywhere from TV shows to offhand comments people I know make; just a semi-serious request to "The Universe" as if the universe is listening, has a will, and might respond positively for requests for intercession. A little weird. Might just be a hold over from Christianity, where the ritual has outlived the belief. As an answer to your question though, you can have a common "rite" that persists past whatever started it and a new mythology can be built around that (or several of those). Next is the Humanism thing. Only met a few real humanists, but seen a lot of it in books. It's based on this idea of a metaphysical connection between all human beings. Sort of a specific type of "spiritual, but not religious." The Hyperion books by Dan Simmons (in addition to just being really good sci-fi) get into this idea quite a bit - especially the last two (which aren't nearly as good as the first two in my opinion). The last one is probably the biggest in the list. "Science!" is a magical force that makes people's lives better. Most don't really understand it but you don't need to know what you are talking about, after all some smart person already figured all this out! My favorite is when you see in writing that some phenomenon is caused by some new theory, as though a physicist with a chalkboard is a magician coaxing some new version of reality into being, rather than just trying his best to understand what might be really happening without any regard to him or his chalkboard - look for this type of language in any sort of science article, it's rampant. This is a god that is trotted out by the elites all the time, and they can do this successfully because people don't see it as a god; they see it as reality. Now of course science (with a little s) is just a thought tool, a process: you make observations, come up with a hypothesis, test against the null hypothesis, and update based on the new observations. Pretty mundane but super useful. As the how-to is lost on the general public but the benefits are not, all this has taken on a sort of arcane aura. The whole "Any sufficiently advanced technology is indistinguishable from magic" (A. C. Clarke) idea. This is a great route to go for the fictional creation of a new god (it seems to be working OK in real life) because it is useful you get The Elites interested and the populace listening, because it is difficult to understand a Priesthood is required to commune with this new "god" on behalf of everyone else. Don't really think you should copy the Science! example exactly, but it offers a great road map for making a new "god" that will become a huge and contemporary force in your setting. [Answer] It seems that you are really asking if new polytheistic gods can be introduced and credibly believed after the introduction of monotheistic religions -- i.e. is there real progress in religion as there is in science. It seems unlikely. Once you get used to seeing the universe as a whole, it's hard to go back on that view and start worshiping many gods, that aren't just avatars of The One, or demi-gods under the control of a super-god of some kind. I think that's your difficulty. Modernity and science assume a monotheistic world in the sense that there is one cause underlying everything. I find it hard to imagine a technologically advanced world (i.e. that has science) but that remains truly polytheistic. I think that's why we feel that the age of the gods is past. > > > ``` > The Sea of Faith > Was once, too, at the full, and round earth’s shore > Lay like the folds of a bright girdle furled. > But now I only hear > Its melancholy, long, withdrawing roar, > Retreating, to the breath > Of the night-wind, down the vast edges drear > And naked shingles of the world. > > ``` > > Mathew Arnold. Dover Beach. [Answer] Nearly instantaneously with actual divine intervention. If a more powerful being appeared and began performing feats that we couldn't scientifically explain, then a new religion would be born within weeks, at most. This could be an alien, time traveler, whatever - any science sufficiently advanced would appear as magic (as they say) and miraculous to many. [Answer] This could occur at any time. That answer is not totally unique from some of the other answers. However, these examples may be, and so may be some of the resulting interpretations. # 1800s * In 1830, Joseph Smith published the Book of Mormon. [Wikipedia's article on Joseph Smith](https://en.wikipedia.org/wiki/Joseph_Smith) notes, "By the time of his death fourteen years later, he had attracted tens of thousands of followers and founded a religious culture that continues to the present." [Wikipedia's article on Mormons](https://en.wikipedia.org/wiki/Mormons) notes, "In 2012, there were an estimated 14.8 million Mormons,[93] with roughly 57 percent living outside the United States." * In 1863, the Seventh-Day Adventist Church was founded. On March 1st, 2017, the SDA church announced over 20 million baptized members. * In 1885, Mary Baker Eddy published "Science and Health". By 1936, the number of Christian Scientists reached 268,915" # He-Man Do you remember He-Man? Maybe you think he was just a minor blip in history. Well, perhaps he has seemed far less impressive from 1986 on, but despite his fate being rather dismal after then, let's not forget the impact he had. Consider, a moment, these two findings: * In the third episode of "The Toys That Made Us" ("TTTMU") (a video available now on Netflix), the story of He-Man is mentioned. Sales forecasts predicted \$38 in revenue during the first year of this toy line-up. It actually accomplished over \$38 million, and went up from there. * 38 minutes into that TTTMU show, according to in an interview with Roger Sweet (who was involved with making the Masters of the Universe toys), some specific numbers were provided: * "The 1982 Masters [of the Universe] line did 38.2 million, + then 80 million in '83, + then 111 million in '84, + 250 million in '85, + 400 million in '86. + Then it collapsed to 7 million." So, this was not a minor blip. In particular, the cartoon introduced Prince Adam, essentially the equivalent to Superman's Clark Kent. Prince Adam could perform a step which turned him from a seemingly incompetent goofball into a revered hero. Despite clearly being fiction, this has inspired children (who placed themselves into the "incompetent goofball" category as they were surrounded by far more capable beings, adults). The children were inspired that they could be more. This resonated far beyond 1987. Decades later, some of those same children have become collectors of He-Man memorabilia. So don't believe for a moment that the children's memories of He-Man were erased in 1987 just because Mattel failed to continue making the same amount of money. Now, let's look at another example: # Star Wars This is an even more compelling example. The first episode of "The Toys That Made Us" was actually about Star Wars, and the third episode (which was about He-Man) notes that the Masters of the Universe line was invented in order to compete with Star Wars toys. However, Star Wars has impacted us beyond just toys. Beyond just toys, though, Jediism has claimed enough followers to become statistically noteworthy. [Wikipedia's article on "Jedi census phenomenon"](https://en.wikipedia.org/wiki/Jedi_census_phenomenon) notes > > In England and Wales 390,127 people (almost 0.8%) stated their religion as Jedi on their 2001 Census forms, surpassing Sikhism, Judaism, and Buddhism, and making it the fourth largest reported religion in the country. [...] In the 2001 Census, 2.6% of the population of Brighton claimed to be Jedi. > > > [Wikipedia's article on Jediism](https://en.wikipedia.org/wiki/Jediism) notes > > In 2007, the Temple of the Jedi Order was registered in Texas. However IRS tax exemption wasn't granted until 2015 > > > If you were to tell people that their beliefs are superfluous, you might find that adherents who lack light sabers might just use the closest available tool, sabers. # Social Movement Consider the sexual radicalization movement. This has expanded from murmurings about a desire for equality, to actual changes in law. Even the United States "White House" was colored rainbow (by shining different color lights on it). The homosexual movement... err... Apparently that's not inclusive enough of a name. Apparently this has become to LGBT movemen--- err--- I suppose there's now a Q, in LGBTQ... Oh, no, now it's become LGBTQQIP2SAA movement? We're now looking at Lesbian, Gay, Bisexual, Transgender, Queer, Questioning, Intersex, Pansexuel, Two-Spirited, Asexual, and Allies? Oh, no, apparently that wasn't enough. Starting out with Lesbian, Gay, Bisexual, Transgender, Queer, Questioning, and Intersex was deemed acceptable. And the remaining Pansexual, Asexual, and Allies were good enough to remain, but those latter four have now been moved into a longer mix of "Curious/ Asexual/ Agender/ Ally/ Pansexual/ Polysexual/Friends-and-family/ Two-Spirit/ Kink" (and more), so LGBTQQIP2SAA wasn't inclusive enough, and so now LGBTQQICAPF2K+ is the latest iteration. The on-topic point I'm making here is that all those letters represent different views with common elements, and even if the movement is fractured on what to name itself, there is a common flag (rainbow), ideals (equality), and they've been able to overturn regulations that had previously been set up by people who pursued different ideals. # Marijuana This might sound like a joke, but I bring it up seriously to make a point. I recall reading about how a couple of traveling rock stars said they prayed to a joint that someday it would change laws and become legal. Well, in years later, you can now read [about the Church of Cannabis](https://www.theguardian.com/global/2017/aug/13/church-of-cannabis-denver-colorado). (Yes, an actual church building.) Now, I know the question asked for something beyond "a small cult". However, the "question" presented actually consists of multiple questions, including "Is there any evidence for a new god emerging in later times?" I mention the Cannabis church simply to demonstrate an example of emergence. (Certainly there are a lot of people who may not have gone into the building, but do subscribe to some of this church's basic way of thinking.) # Revelation's Beast From Christianity's Sacred Text, Revelation 13:3 (International Standard version) states, > > Rapt with amazement, the whole world followed the beast. > > > This indicates that, during the end times (which occur just before the end of "life as we know it", when all sin is purged), a world-wide religion is created. # What all this means Now that I've provided various evidences, let's look at the questions. > > How recently could a god be born? > > > The evidence I showed indicates that the population is ripe for susceptibility to adopt new faiths. > > What is the latest point in history that a new god could be worshiped by some intellectual and cultural elite; i.e. not just a small cult? > > > First of all, it may be worthwhile to identify what a "god" is. Going back to the Roman times, there's a rather strong indication that gods were used by the politicians to unite cultures and collect sacrifices, essentially as taxes. So they fulfilled roles in society other than just beliefs. Today, we fulfill many of those roles with made up entities, from mascots that unite local sports teams to superheroes that generate revenue for (corporate) leaders. As for beliefs, there are some beliefs that have attracted large numbers of adherents. Significant devotion can be demonstrated by the followers of David Koresh (leader of a group who died off in/near Waco, Texas), and specialized/devoted buildings are created in numbers that are probably largely based on money (to afford the buildings), which is largely generated by having large populations. So we have the creation of powerful (artificial, fictitious) entities, and we have a willingness for new beliefs. The creation of a new god would simply be a melding of those two aspects, both of which are present in current society. Although that may not have actually happened yet, the conditions seem ripe for such a possibility, indicating that [as late as today] it "could" happen (which is what you asked). And there are plenty of Christians who expect that it will happen. > > is it possible for a new deity to emerge in medieval or later times? > > > I just answered: now, and in the future too. > > Is there any evidence for a new god emerging in later times? > > > No. Well, I'm not offhand aware of one. And maybe there is no widely known example that has actually occurred in recent history. (And your question indicates you're not just interested in a "cult", but something grander.) If that's the case, then no strong desire is going to be able to change what has actually historically happened. > > How does the worldwide dissemination of exclusive monotheistic religions affect the acceptance of new gods? > > > In [1 Timothy, Chapter 6](https://www.biblegateway.com/passage/?search=1+tim+6&version=NIV), verses 2-4, we see, > > These are the things you are to teach and insist on. If anyone teaches otherwise and does not agree to the sound instruction of our Lord Jesus Christ and to godly teaching, they are conceited and understand nothing. > > > This teaching basically excludes later contrary religious ideas. Whereas some Roman gods were simply modifications of Greek gods (actually, the Greek Apollo didn't even get renamed by the later Roman empire), the idea of monotheism provides a context that is rather unfriendly to new gods entering the picture. That is, if people believe in polytheism, they may be more ready to simply accept a new god. Those who have embraced monotheism may question whether to call the God Yahweh or Allah, but the idea of just adding a new god to the mix won't be so readily acceptable. So basically these religions have raised the bar. One could see polytheism as being sort of a step in between the belief that monotheists have, and the clearly unquestionably widespread recognition of superheroes. Finally, I'd like to bring up that this is the WorldBuilding site, not [Stack Exchange's History site](http://history.stackexchange.com). Therefore, I take the core of the question to be about what could happen, not necessarily what did happen. So even if some of my theoretical possibilities didn't actually happen yet, the point that some of these things are so close to happening proves the viability to be pretty believable (conceptually). So, as I summarized in my very first sentence of six words, I will boil all that down into this summary of even fewer words: it can happen (still!) [Answer] What about [Allah](https://en.wikipedia.org/wiki/God_in_Islam)? On one hand, one could say since islam is abrahamic religion, it's not a new* god*. On the other hand, Allah is definitely differs both from christian trinity and the God from judaism. According [english wiki](https://en.wikipedia.org/wiki/Islam), Allah originated in the early 7th and [russian wiki](https://ru.wikipedia.org/wiki/%D0%98%D1%81%D0%BB%D0%B0%D0%BC) states that islam is the youngest religion. I suppose muslims have different opinion related jewish or agnostics so there is no the only correct answer. ]
[Question] [ So I've been thinking about the idea of a series that takes place on a small fleet of generation ships, traveling at around 10% of lightspeed to Proxima Centauri, which should take around half a century. So the flaws here have been pretty well laid out in detail by Kim Stanley Robinson [here](https://boingboing.net/2015/11/16/our-generation-ships-will-sink.html), who also wrote the book Aurora with the same argument. While I think his problems have solutions, these solutions lead to another problem: Anyone who is capable of building a working generation ship has no reason to do so. In order for generation ships to work, you essentially must have fusion power and nearly perfect self contained life support. You also need genetic engineering to fight evolutionary pressures as well as either transhumanism or medicine advanced enough to deal with damage from stellar radiation and the possibility of major ecological problems. All of this basically gives you the ingredients for a post-scarcity utopia, which people have to then leave to go on these ships in which scarcity comes from the fact that you only have whatever you started with. On the upside this does solve another major problem, that we have no idea whether there are any habitable destinations, as we can simply live in space within the new solar system. On the downside, if you have all of these, you then have nearly infinite growing space within our own solar system and thus no real reason to leave in the first place. This post scarcity context does at least solve one problem without any major downsides, it means that there is no real need for anyone back home to turn off the lasers that allow your such a ship to be a somewhat workable beam-rider. Alternatively it could also allow you to synthesize enough fuel even with insane mass ratios. There is also a really cool means to slow down, called the magnetic sail. Anything I'm missing? EDIT: One major point I failed to make fully is that when I say live in space, I mean to live in newly constructed habitats in the new solar system, not to remain on the ship itself. Also, I think the deeper problem is the lack of habitable destinations that we know of. Either the world will be uninhabitable, in which case it will need terraforming that could last centuries, or it will be habitable and almost certainly have something alive on it. Specifically a dead world would never have oxygen (like Mars, it would turn to rust). The better question then becomes what is the point of traveling to a new solar system just to live in space stations? EDIT2: I finally corrected the travel time. My original mistake was using delta-v instead of speed, which would effectively cut the travel time in half using a variation on the flip and burn style popularized by The Expanse. [Answer] I think there's two things missing. The first is that we do hard things all the time. Its standard practice for humanity to do things that were impossible a generation earlier. I think the real key is motivation. A society's motivation for generation ships is the same motivation a tree has to produce seeds. Why produce seeds when, to produce seeds, you need to be so successfully rooted in such a good place that you could just stay there forever. Trees produce seeds. There's a reason. The motivation lies in the long game. The tree "knows" that sooner or later something is going to happen. A lightning strike. A prolonged drought. A plague of beetles. Homo sapiens. The good life may look like post-scarcity, but a handful of individuals know the truth. As perfect as their fusion may be, one day, our star is going to go out. Its going to die, and we are going to be cold. Very cold. The generation ship would not be a uniform sampling of society. That would be like a tree packing up some roots and leaves and bark and sending it out on the wind. The mother of thousands and [mother of millions](https://www.youtube.com/watch?v=DkiiOK9MBTs) actually do pack up a whole plant, but they're the odd ball, not the norm. You would select a very very specific subset of society which is designed to germinate. Thus their social needs are very different than the whole. In a post-scarcity world, this might not matter. But we often have this funny illusion that there's a discrete transition from scarcity to post-scarcity. I would argue there's litte reason to believe this to be true. You can get to almost post-scarcity by managing the expectations of the citizens. If a citizen never wants what they cannot have, its post-scarcity as far as they are concerned. But that may not be sustainable. You're not quite there yet. You're consuming resources too fast to be post-scarcity (and by "too fast" I mean "consuming finite resources at all"). So you bundle up a seed You bundle up a subset of society which is as close to post-scarcity as you can possibly manage. And then you send them out and hope they reach somewhere to germinate on. While your tech may not be sufficient to provide this post-scarcity illusion for the general population, the driven population on the ship can endure much more stringent requirements put on them. We have germinated 2000 year old palm seeds, even though no palm that we know of has lived 2000 years. As for all of the difficulties in finding the right planet? That's another reason I recommend thinking in terms of seeds. A well rooted mesquite tree will produce literally hundreds of thousands of seeds in its lifetime. A valley full of them can produce so many seeds that, were they playing Powerball (with a jackpot odds of 1:292,201,338), it starts to look like a sure thing that they'll hit the jackpot. Sending out a generation ship? Foolish and wasteful. Sending out a million generation ships? Now things start to get interesting. > > "A society grows great when old men plant trees whose shade they know they shall never sit in." > > > [Answer] Let's split this question to some parts that I deduced from your question ### 1. Why would anyone work on something that they will never be able to use? First, there are people who are interested in things they can't actually use. For example, Ada Lovelace invented a programming language and wrote code for the Analytical Engine even though it was never built. Likewise there were algorithms for quantum computers (the best known is the Shor algorithm) that were developed before quantum computers existed. So people may build spaceships because they want their grandchildren to have a good life, knowing that they can not use those ships themselves. Second, they may feel responsible for humankind. We only have one planet with humans on it. If something bad happens to earth, humans will go extinct. If we can colonize another planet, the danger of going extinct is much smaller. ### 2. Why would you land on a distant planet and try to colonize it, when you can live in an orbit around that planet? Those ships may be well engineered but won't work for eternity. While travelling to the distant planet, the ship will be hit by some micrometeorites. Those damages must be repaired. The ship will lose some air because of the damages. The life support systems will need spare parts for repair. The fusion material that is powering the ship won't last forever. So you will at least have to harvest some material from the planet. Also some of the people will want to live on the planet. Why would you want to live in a cage that is flying around a planet when you can as well live on the planet and maybe have a whole country for your own? The ship will always be in danger of being hit by a meteorite or a failure of life support systems. ### 3. Why would you even travel to a distant star when you can stay in earth orbit? A combination of questions 1 and 2. We need a backup for humankind. When Earth is so badly destroyed that humans can't live on it anymore, you may not be able to harvest new materials for spare parts or new fusion material. Also there are dangers that not only affect Earth itself but also the surrounding space or the whole solar system (gamma ray bursts, attack by a more powerful alien species, the sun becoming a red giant etc.). And of course it's nicer to live on a planet than in a spaceship ### 4. Are Generation Ships inherently implausible? There are other reasons why generation ships may be implausible. * The life support systems could fail - all humans die * A breach in the hull - much air flows out - many humans die * The ship needs artificial gravitation by rotating it. If something breaks, the ship is ripped apart - all humans die * Some miscalculation for the radiation in space - all humans die * There's no habitable planet in the destination star system - all humans die * some people going crazy and destroying parts of the ship - all humans die * the artificial gravitation needs to be turned off for some reason - the humans degenerate and aren't able to land on the planet anymore - all humans die * some bad epidemic - all humans die etc. It may be far easier to build a machine that is able to breed a cryoconserved fertilized human egg on the surface of a distant planet than to build a ship that is able to transport living humans, animals and plants to that planet. Also be aware that you need more than just two humans to colonize a planet. Some scientists calculated that the absolute minimum is 98 non-related humans and a strict plan who gets children with whom to reduce incest related genetic defects to a level that long-term colonization is possible. So that ship will be pretty huge and expensive compared to an automated human breeder and AI-nanny ship. ### Answers to comments: I'll write the answers here, because the comments are limited to 600 letters. > > You would be able to built quite a large number of rotating habitats, > using just the mass of Mercury. > > > That's true, but I try to use only current or soon available technology in my assumptions. The ISS may be large enough to support enough arable land (in shelves) to build a biosphere for one person that could spend their entire life in space. The cost to launch all the ISS parts into orbit, is something around 150 billion dollars. Even if future technology can lower the cost by 99%, it will still be 1.5 billion dollars for each person. So you may be able to build an Elysium for the super rich people, but you won't be able to build space habitats for all humans, because it's just far too expensive. > > Also, terraforming a planet so that it is actually earthlike is > incredibly difficult and may not actually be possible > > > I'd assume, we will fly only to stars that are guaranteed to have at least one "rocks and water"-planet in their system, so we can dump some algae and plant seeds on it to produce enough oxygen, so humans can survive on it after a few decades. Or maybe we fly only to planets with a high oxygen level, so we can land there on arrival. > > A note on rotating habitats; the rotating cylinders are unlikely to be > a visibly rotating section (like Babylon 5 or similar). Instead the > rotating section will likely be contained within a non-rotating shell. > > > That may be a good idea. Another idea that came to mind is that you don't even need a rotation because the main engine has a constant 1g acceleration. We would need that anyway if we wanted to go to Proxima Centauri within 100 years. > > And of course it's nicer to live on a planet than in a spaceship It's > nicer, when you have always lived on a planet. The third generation on > a generation ship is likely to not agree with this statement. > > > I think it may be even opposite. For us it is new and exciting to live on a spaceship. If you were born on the ship, you may be more interested in exploring a planet. Just imagine you'd live in a single skyscraper your entire life. > > "all humans die" section: the same list of arguments (with > translation to analogous technologies) applies to the era of > exploration by sailing ships. As we all know, that was wildly > unsuccessful (he says, sarcastically) > > > There are some similarities but also many differences between interstellar travel and early intercontinental sailing. The sailors often had problems with rotten food, they didn't know if they'd arrive somewhere, they heard rumors of huge octopusses or whales or sirens that would kill them, they didn't exactly know if they would fall from the edge of the world etc. but they were still brave enough to sail away. And many of them died. Mostly because they starved or dehydrated or because the ship sunk or became unmanageable. The problems with interstellar travel are different. The ships are far more expensive. Just think ahead of what I said about the ISS. Even with much cheaper spaceship construction options, you'd have to pay over a billion dollars to theoretically transport one person to a distant star - based on the construction of the ISS, which is hardly more than a balloon made from steel. You could easily punch a hole in its hull with a nail and hammer. For a ship that has a hull which is strong enough to withstand the radiation of the interstellar medium and the impacts of micrometeorites at 10% of the speed of light, you'd need a lot more money. The calculations regarding 98 persons to colonize a planet applies to the launch of the mission. When you arrive, that will be a lot more people. I can't find more detailed data of that study, but let's just assume 500 people on arrival. Then you will most likely also want some animals to be on the distant planet. For example cows, chicken, pigs, dogs, cats. All of those also need enough space and food for 500 of each species. So the calculation is like 6 species times 500 individuals times 15 billion dollars = 45 trillion dollars for one ship. The cost may be too high for humankind to even build one ship. So if you can bring up the money, you need to be absolutely sure that the ship will arrive safely on its destination. The old sailing ships were expensive, but the people were still able to build several hundred ships that were capable of intercontinental travel. So you had enough tries to colonize a distant continent. [Answer] Flip the question around Let us accept the premise that a generation ship is not viable without the technological ingredients for a post-scarcity utopia. Now add the assumption that this situation has been achieved without a massive (>80%) population crash on Earth. What remains is a situation in which there are billions of people who can do almost anything they like. The one type of activity that there will be a shortage of is meaningful activity - it would take a relatively small percentage of the population to maintain essential services (with the aid of machine intelligences) and most of the population simply lacks the aptitude and/or ability to conduct serious scientific research (more on research later). Out of billions of people seeking something meaningful to do with their lives, I would be amazed if there were not a large number who dedicated themselves to spreading humanity through the universe. While it may seem a foreign concept to some people today, many people throughout history have dedicated themselves to projects that they knew they would never see completed. Other motives for embarking on a generation ship voyage include seeking fame, seeking knowledge (how many astronomers would decline the chance to be the first observer on the other side of the Oort Cloud?) or trying to preserve a particular human culture in isolation. Those are just the first thoughts that spring into my mind, there are doubtless many, many more. The question is not whether anyone would want to leave Earth and entrust themselves to the unknown - a small percentage of humankind has been doing that since we came out of the trees. The question is how many millions will be in that small percentage and what variety of motives they will have. [Answer] It's basically a political issue. While people of your way of thinking might not use generation ships, others might. Sepcifically...religious types. Pilgrim Fathers who need to get as far away as possible from other humans to set up their utopia. Cults who believe they have a divine mission to populate the universe. Those who believe there is a Promised World awaiting them at location X because their prophet saw it in a dream. Or refugees from what they see as an oppressive government. Or criminals bent on escaping justice. Or megalomaniac tech billionaires who want to build their own space empire. There could be a racial angle. Fascists who want to 'preserve the purity' of their particular race. A group with a grudge who want to protect their culture from being assimilated into the majority. All of these things involve getting far away, and a generation ship might be the best way to do it. [Answer] > > In order for generation ships to work, you essentially must have fusion power and nearly perfect self contained life support. > > > Not really. It just needs to be pretty good. You can plan for some level of waste, and include extra supplies. Assuming you lose 1% of your supplies per year, .99^100 = .366, so you just need to bring 3x as much stuff as is necessary to sustain life. That 1% is something I just pulled out of thin air, in the long term whisky distillers can hit around 3%. With [wooden barrels](https://www.alcademics.com/2014/01/how-much-pappy-van-winkle-is-left-after-23-years-in-a-barrel-.html). If your spaceship can't beat wood by a couple orders of magnitude, I'm not getting on it. > > You also need genetic engineering to fight evolutionary pressures as well as either transhumanism or medicine advanced enough to deal with damage from stellar radiation and the possibility of major ecological problems. > > > Not much evolution happens over 100 years. Inbreeding could be an issue, but that's just a matter of having a large enough populaton and keeping good records. Radiation is an issue, you'll have to come up with a method of shielding, but that's an engineering issue, not fundamental physics. Thick enough walls is where I'd start, but I'm no rocket surgeon. > > All of this basically gives you the ingredients for a post-scarcity utopia, which people have to then leave to go on these ships in which scarcity comes from the fact that you only have whatever you started with. > > > I don't think this is obvious at all. Even assuming you disagree with my previous two points, and think we necessarily can design a post-scarcity, free healthcare space hab. All we have to assume is that society can build this for some people. There are billions of people on Earth. They'd be working together to build this ship for tens to hundreds of thousands at most. Now, we need some motivation to go to another planet, but that's too plot specific. Maybe Earth is truly doomed long run and we need somewhere to save the human race long term. The space between self sufficient indefinitely and self sufficient for a couple hundred years is pretty big. [Answer] What's missing is the ongoing march of technological progress. What's an insurmountable problem this year is next year's high school problem. Whether through simple miniaturisation or wholesale new breakthroughs all these problems can be solved. All you have to accept is that it's not you or your children getting on these ships, but you could be doing the work that makes them possible for the later generations. I remember the excitement when the first exoplanet was discovered, now they come thick and fast. So don't look at generation ships with our technology, look at them as a range of solvable problems and you might see them getting slowly closer. [Answer] About the why, even in post-scarcity society: Philosophical disagreements and lack of meaning. People will always disagree about the best way to live. One may even say that how to answer this question is what divide a society from another. Even in a post-scarcity society these divergences will exist. How should Man live? What is a correct life? What is Good and what is Evil? I'd say that a post-scarcity society will exacerbate the divergences. If we go by Plato there are three main human temperaments: the worker, the warrior and the philosopher. There will be nothing left for the workers to do: the utopian economy provides everything. There will be nothing left for warriors to do: the resource wars are a thing of the past. Only the philosopher will be fine. Those with a temperament to be workers or warriors will start mess things in the Utopia: many will become addicts to drugs, other will start causing trouble fighting in the streets for the pleasure of fighting, causing mayhem for the sake of mayhem. Also, the philosopher will keep concocting philosophies, ideologies, and many of these strange ideas will be quite dangerous for Utopia. All of them will be contesting the Utopia's way of life because it deprives them of meaning. You have to get rid of these people regularly. But you don't want to kill them, that's inhuman and unnecessary. So you build these huge generation ships and send them far away, to places where Utopia does not exist, so that workers can work and the warriors can fight fulfilling battles and the dissatisfied philosophers can try to implement their strange ideas. The new worlds in distant stars provide the only thing that is scarce in a post-scarcity society: Meaning. That many of these new colonies will self destruct is irrelevant. The dissatisfied have the right to die trying to fulfill their destinies and finding meaning. [Answer] ## No difference from deep space habitat In order to travel between star systems for that amount of time, the "generation ship" would need to be essentially a self-sustaining deep space habitat. Therefore, it needs factories and a university and farms and all the necessities of modern (to whatever time period) civilization. The fact that it has engines and is moving between star systems is relevant, but the key is that this habitat needs to be able to manufacture (given the raw materials) anything it needs, and recycle nearly all its wastes. Perhaps it needs to visit a star system every couple of hundred years to fuel up on whatever it uses (uranium for fission, hydrogen for fusion, exotics for something else) and stock up on metals and organics, but it should not need to drop anyone off if it doesn't need to, because there's no guarantee there will be somewhere for someone to live. Part of its mission can definitely be colonization. Perhaps it keeps frozen embryos to decant when it reaches a new planet. Perhaps part of the process in visiting a new system is that it spends a couple generations creating a colony or a new traveling habitat just because it needs to get rid of surplus population. Colonization should not be its entire mission, though. It will be conducting research, engaging in innovation and keeping in (delayed) touch with the mother planet as long as a coherent signal can be maintained, or boosted from relays in deep space. [Answer] There is a good time slot for generation ships between achieving post scarcity and getting to star-lifting levels of engineering. It wouldn't matter whether you live in an artificial habitat here, there or drifting inbetween, but you still get the safety of not having all your eggs in one basket. And perhaps satisfy parts of our curiosity. An additional factor to consider: generation ship implies biological life, at least for most purposes. That term might become obsolete if we redefine us before we depart. [Answer] You are making one big assumption that may in fact not be warranted. You assume that generational ships (or any high tech like that) are used only out of necessity. But that's often not the case in human history. In fact, the more prosperous you get, the more likely you are to do things just because you can. Think about all the conquerors who traveled to different continents, often under challenging and potentially fatal conditions. They didn't really have to do that, they wanted to. The USA didn't really need to go to the moon, it was done basically to show that they could. Similarly, your advanced civilization could opt to do things just because they're interesting, challenging, and opens up new frontiers. [Answer] I've been wondering for a while now why you would even have living humans on-board for most of the trip. 3D printing is making it's rise, and we've been printing simple bodyparts for a while now (<https://www.smithsonianmag.com/science-nature/3d-printed-ears-grown-stem-cells-are-finally-on-their-way-180961605/>) The biggest problem with this type of printing is how to get the semi-random mini-bloodvessles throughout the bodyparts you are printing to keep it alive and questions on how we can create specific cells in the right positions to function. Once these are solved there is virtually nothing stopping us from printing entire humans. So what you do is gather a DNA database, potentially you would even have the ability to have human DNA be computer-generated. You send this on a ship to the starsystem you want with a bunch of air and compressed dead biomatter. Once you get close to your destination you take the biomatter and start building living cells and with that print living and breathing humans (already adult-sized if need be so you can skip infancy). Do this at a distance of the planet where you have time to teach them what they need to know and make them the specialists you need. This way you only need the life support for the last leg of the journey and no super-special technology for cryogenics or long-term space-based survival strategies with limited resources etc. [Answer] # If You Build It... Why did cave men leave the safety of their home tribe to wander into the unknown? Isn't that foolish? For the individual cave man, it is. For the genetic inheritance of cave men, it's a prudent gamble (hence, the Polynesian explorers mentioned elsewhere). Humans have a wanderlust, and always have. Pretty much every living creature on the planet seeks out and exploits every niche it can sustainably inhabit. If humans are able to inhabit the extrasolar planetary niche, they will do so for no other reason than that THEY CAN. Not every human will do so, but you are virtually guaranteed that for every day between now and when a generation ship becomes available, you can ask the question: "Who wants to leave Earth forever and live in relative deprivation to explore the stars?" and thousands, possibly millions of hands will go up. # ...Who Pays? Ok, so we agree that there will always be someone who wants to go. But why would the rest of society expend the resources to do so? You could just hand-wave it away as the fact that your post-scarcity society is so filthy stinking rich that it can extravagantly expend the resources to build such a thing without batting an eyelid. But I find that somewhat dissatisfying. Let's put on our post-scarcity hat and think. One of the arguments for post-scarcity is that AI and automation will make production cheap and easy. Ok, I buy it. But that also means we have likely passed The Singularity, and are dealing with at least one super-intelligence. Why would that guy allow the resource expenditure to build one or more generation ships? What does a super-intelligence want, anyway? I think it wants two things: First, it considers itself a living being, and thus, it wants to procreate like every other living being (because beings that reproduce out-compete those that don't, and so a super-intelligence can easily rationalize propagation as an optimal survival strategy). It could surely venture out into space by itself, but why do that when you can take a whole ecosystem of servan^H^H^Hcompanions with you? After all, humans represent the pinnacle of nanotechnology and provide extremely energy-efficient solutions to a wide range of problems. Second, we just have to think about what that SI will be doing with all its time. It won't be babysitting humans, that's for sure. So it will be producing the one thing that is of any value to an SI: knowledge. And there is only so much knowledge which can be discovered and produced while sitting at home. If knowledge is the one thing in the universe that you value, then you are definitely going to expend resources to go find more of it. Who knows what you can discover? New biology? New planetary science? New stellar phenomena? The galaxy is your oyster. [Answer] I want to work from the assumption that the challenges have been solved but theres no reason to do so. In that case, generation ships are absolutely plausible. People are not inherently logical. Therefore it is reasonable to assume that at least one person will participate in an activity even if the activity itself does not seem reasonable through a logical point of view. And therefore the possibility that generation ships will be used still exists. Even if technology exists that can propagate sentient life through out the stars without the transportation of living people. Someone with enough resources could still utilize generation ships simply under the impression that it is more "natural" or "cool". [Answer] It is possible to build artificial space habitats with materials from small solar system objects like asteroids and comets. So eventually there could be tens, hundreds, thousands, tens of thousands, hundreds of thousands, millions, etc. of such space habitats with populations of thousands of persons each. And of course adding an engine and fuel supply, etc., to such a space habitat would turn it into a vast generation ship. So I can imagine that a fleet of several such generation ships might be sent to colonize some region in the outer cometary halo of our solar system. At a speed of one percent of the speed of light, it would take such a fleet 100 years to reach a part of the cometary halo 1 light year from the Sun. At a speed of 2 percent of the speed of light it would take such a fleet 50 years to make the journey, at a speed of 3 percent it would take 33.333 years, at a speed of 4 percent it would take 25 years, at a speed of 5 percent it would take 20 years. If a fleet of several such generation ships is sent to colonize some region in the outer cometary halo of our solar system. At a speed of two percent of the speed of light, it would take such a fleet 100 years to reach a part of the cometary halo 2 light years from the Sun. At a speed of 3 percent of the speed of light it would take such a fleet 66.666 years to make the journey, at a speed of 4 percent it would take 50 years, at a speed of 5 percent it would take 40 years, at a speed of 6 percent it would take 33.333 years. So possibly several fleets would be sent from the inner solar system to colonize various regions in the cometary halo. And after expanding in the cometary halo for a period, perhaps centuries, each such colony there might send out one or more fleets of generation ships to colonize another, and farther, region of the cometary halo. The average distance between a star and its nearest neighbor is about five light years in our part of the galaxy. At a speed of about 1 percent to 10 percent of the speed of light, it would take about 50 to 500 years for a generation ship to travel straight from the inner solar system of one star to the inner solar system of the other star, and about 1,000,000 to 10,000,000 years to go from side to sie of the disc of the Milky Way Galaxy.. But if generation ships make voyages of 1 light year each to colonize regions of the cometary halos, and take 100 to 300 years to each the stage to send out long distance colonizing expeditions of their own, the colonizers could reach the inner solar system of a star 5 light years away in about 450 to 1,700 years. And travelling at about 100 to 300 years between jumps, and jumps of 1 light year each at a speed of 1 percent to 10 percent of the speed of light, a society could expand in all directions at an average speed of about 110 to 400 years per light year of distance. Thus such a society could eventually colonize the entire galactic disc of the Milky way Galaxy, 100,000 light years in diameter, in about 11,000,000 to 40,000,000 years, if they started from an outer rim of the galactic disc. If the inhabitants of such space habitats expect that they and their descendants will live in space habitats forever, and have no desire to land on any habitable planets they might possibly find, Generation ships made of such space habitats could make much longer distances. Possibly some generation ship fleets might travel 10 light years in a single voyage, taking 100 to 1,000 years. And if such voyages are successful, some generation ship fleets might later travel 100 light years in a single voyage taking 1,000 to 10,000 years. And eventually generation ship fleets might make voyages of 50,000 light years, taking 500,000 to 5,000,000 years, reaching and beginning to colonize distant regions of the galaxy. a copy of my post from: <https://historum.com/threads/generation-or-sleeper-ships-which-would-be-the-better-more-realistic-option-for-space-travel.181701/#post-3223023>[1](https://historum.com/threads/generation-or-sleeper-ships-which-would-be-the-better-more-realistic-option-for-space-travel.181701/#post-3223023) [Answer] In every sci-fi story I've read involving generation ships, the technology improves until they can send out a faster ship which of course then catches up with the generation ship. There's no reason why that won't happen IRL. So a society shouldn't even bother building a generation ship in the first place. ]
[Question] [ In fantasy works, it can be interesting to imagine an infinite world. It means you can travel in any direction for as long as you want, always discovering new lands, new cultures, new landscape, etc. By infinite world, I mean an infinite habitable surface. However how should such a world be shaped to have a "normal" sun cycle ? That means to have the following features (which the Earth actually have) : * The sun travels through the sky and when the night comes it disappear behind the horizon. * There are places on Earth with seasons. For simplicity, assume it only means longer days with the sun higher in the sky during some periods (summer) and shorter days with the sun lower in the sky during others (winter). * There are places on Earth without seasons. * The world looks locally flat (there can be geological stuff, like mountains, but no obvious curvature of the world at short scale). * The fraction of the world which is habitable is infinite. Note that since it is a fantasy question, the world can * Have a different sun every day. * Some part of the world can have behaviour not known on Earth (for examples never ending darkness passed a given point). * Break any law of physics (for example, the trajectory of the sun can be anything, and the gravity does not need to be explain or even explainable without using magic). It is clear that given all that, the world can not be flat, because if it was, the sun would never disappear behind the horizon. It is possible to give some kind of curvature to the world to avoid this, but then the question of seasons arise. [Answer] If you are okay with breaking every laws of physics, simply get rid of euclidean geometry and get "overlapping" space. Your world can be the size and shape of Earth. You start on point 0, walk to East, at some point if you trust stars and such you are back at your starting point, but in fact you got to a second point, overlapping with point 0. You can make only the Earth overlapping, in this case overlapping areas will share the same stars, the same seasons... Or put some more magic into it and consider that everything share the overlapping geometry. In this case you can just do whatever you want with overlapping geometry as a blanket excuse. [Answer] "Infinite" is really a big, big word. If you want to keep any semblance of physics, consider a world that is finite, just really big. Even a mundane [Niven ring](http://larryniven.wikia.com/wiki/Ringworld) is big enough for all practical purposes - at 1AU radius, to walk around it would take about 20 thousand years of nonstop walking (and that still leaves several Earth worth of width unexplored). And there are bigger structures possible - an [Alderson disk](https://en.wikipedia.org/wiki/Alderson_disk) is much, much bigger and if the Sun is made "bobbing" through the hole, you'll have reasonable day/night cycle, and with some rotation, you'll have seasons. And you can make Niven ring or Alderson disk around Betelgeuse or a quasar for (much) more habitable space. You can also make the beings smaller - if your humanoids are 1mm tall, even a common Earth like planet will be like an infinite world to them. And that's still within physics as we know it. [Answer] Well, if you're already accepting that there is some magic, you could try an infinitely long cylinder, orbiting a cylindrical sun. Obviously in our universe, these would collapse in on themselves lengthwise, but with magic anything is possible. Another possibility - the world is an infinite sheet, with a hole in it through which the sun passes back and forth. This also gives you a reason for different societies affected by the temperature at different distances from the sun-gap. [Answer] The world can be made up of an infinite 2-dimensional plane of arbitrary thickness. In this plane, there exists an array of holes which pass through the plane. For ease of visualisation, the infinite plane would be similar to this picture, but with smaller holes relative to the normal land area than pictured. [![enter image description here](https://i.stack.imgur.com/DWqvCm.jpg)](https://i.stack.imgur.com/DWqvCm.jpg) Around this plane, there exists an infinite number of suns. These suns periodically cycle between the two faces of the plane, entering a different hole each time. The suns follow a repeatable pattern in their cycling, and they sometimes spend a shorter duration of time on one half of the plane and a longer duration of time on the other half. Therefore, you get summer on one side of the plane and winter on the other side of the plane. Some suns do not cycle with any variations in their relative time, and these locations do not experience seasons. This also adds some additional interesting elements into the world, since there has to be, by necessity, regions on this infinite plane that obtain close to zero sunshine (the dark zones). These zones may be inhabited by different creatures. Also, falling into one of the holes on the infinite plane will allow you to easily travel to the other side of the plane - just make sure not to do it when a sun is setting in your hole! ## Conclusion The sun travels through the sky and when the night comes it disappear behind the horizon. - Check. There are places on Earth with seasons. For simplicity, assume it only means longer days with the sun higher in the sky during some periods (summer) and shorter days with the sun lower in the sky during others (winter). - Check. There are places on Earth without seasons. - Check. The world looks locally flat (there can be geological stuff, like mountains, but no obvious curvature of the world at short scale). - Check. The fraction of the world which is habitable is infinite. - This is kind of trivial, since as long as the percentage of habitable surface is nonzero, the total habitable surface would also be infinite. [Answer] I had come up with one such world recently. The habitable surface is essentially along the convex side of a parabola. This can either be just a parabolic ribbon, or preferably along the center of a hyperbolic paraboloid (See the second image at [wikipedia](https://en.wikipedia.org/wiki/Paraboloid), or [this image](http://artmuseum.princeton.edu/legacy-projects/Candela/images/thm/hypar-figs11.gif), in which the habitable area is on the upper side of the red arrow), just because I think infinitely tall mountain ranges would be a cool bonus feature. As you suggested, there are multiple suns (actually infinitely) that pass over the land in a slightly wider parabola. The suns move most slowly at the apex, and move faster and faster at the extremes, so that creatures living on the apex of the parabola experience normal Earth-like days with one Sun which rises and sets, whereas creatures living in the extremes experience "days" that approach an infinitesimally short over-head passage of the sun - with the leading side of the parabola instead having the infinitely many approaching suns placing it in an eternal dawn, and the trailing side of the parabola having the infinitely many receding suns placing it in an eternal dusk. This would be an excellent discovery - one could start out in an Earth-like world, and as they travel further "West" (toward the setting sun) the days grow shorter and shorter and the dusk longer and longer until at one point they see for the first time a sun rising while one is still setting. Eventually they reach a land of eternal dusk that stretches on forever... an excellent place for vampires and the like. As for your criteria: * The sun travels through the sky and when the night comes it disappear behind the horizon: Not everywhere, but true near the apex. * There are places on Earth with seasons. For simplicity, assume it only means longer days with the sun higher in the sky during some periods (summer) and shorter days with the sun lower in the sky during others (winter). This can be easily incorporated by varying the path or speed of the suns, nothing more than a hand-wave really * There are places on Earth without seasons. With complete control over the path of the suns, this is just another handwave * The world looks locally flat Sure, this just depends on scale * The fraction of the world which is habitable is infinite. Check [Answer] Now for a truly ambitious setting: Consider more dimensions. For simplicity, let's assume the planet is a five dimensional hypersphere (there are some good reasons why the number of spatial dimensions has to be odd). The hypersurface is a 4D closed hyperspace. There are 3-dimensional cracks (or just boundaries between geological objects) on the surface, just hairline thick (or maybe planck length wide). Each of these cracks hosts 3-dimensional beings that somehow got into this world, and they are quite unaware of their universe (at least until they start building modern physics theories). The seepage of 5D photons and energy into the 3D subworld could provide some truly fantastic possibilities, there is a lot of 3D subvolume, especially if the cracks are fractal like, and if you somehow manage to cross the extra dimensions, you can get into neighbouring world (which might be just millimetres away in any of the two remaining axis). Yes, this gives extra planes of existence on a scientific basis. Wizzard's training would include a lot of n-dimensional geometry I guess. Consider Greg Egan's [Diaspora](http://www.gregegan.net/DIASPORA/DIASPORA.html) for some mathematical description of 5D universe. [Answer] I've actually wondered about this sort of thing before, this is what I came up with. An infinitely long cylinder with stars orbiting it and moving downwards. Illustrated path: ``` \\| \| \| \| \| \| \| \| \| \|\ \| \|/ \| / \|/\| / \| \| \| ``` If you want to eliminate the "where did they come from" aspect you could say it's a geometric ray* rather than line (only expending infinitely in one direction) and at the top of the world there's a super star or star forge type of thing that spits these out. [Answer] I'd go with a cylinder world. It would only be infinite on one axis, but you would get the same ground area in the end (infinite). This cylinder could be orbiting around a cylinder star; if your world's axis tilt slowly back and forward that could give you seasons, but the more you go in one extremity or the other, the more extreme the seasons will be (in both case, your distance to the cylinder star would close to infinity). Another options would be to have an infinity of small stars orbiting around your cylinder. That would have more possible variations for seasons as you may have them orbiting on an ellipse (a little like comets around our sun), but not be synchronized with each other. Also their distances, sizes, and orbiting speed can vary, which would allow you to have areas with different day length or seasons cycles (you could travel for a few thousands km on a cold/arctic world, then arrive in a tempered or tropical area, etc...). Gravity and other stuffs should work pretty much like ours so you could have some moons orbiting between the suns, and why not have your inhabitants use artificial satellites. PS: The cylinder is also rotating along its axis in order to have both seasons and day/light cycles [Answer] Physics does not have to be the same. We are already presuming differences in spacetime geometry; why not change some of the concepts as well? Here, we have things like a constant speed of light. There, why not the appearance of a constant angle to the "sun", regardless of ones position on the plane? It seems as if light rains down from an infinite-distant source, being parallel rays. But there is no source: it's a field of radiation as infinite as the world. An observer with eyes or photographic equipment would image a point at some specific angle, like an infinite-far star, that moves over the course of a day. But there is no star; just incoming radiation that's always in transit. A hot tiny point is not very cheerful, so other effects blur it out to a friendly 1/2 degree of an arc. This can be done with diffusion zones that lie above the ground and have other effects too, as well as effects of the atmosphere or layers thereof. It makes sense that the sun would be infinite too, right? [Answer] For an annoyingly trivial answer, simply make the planet an infinite sphere, and make the sun infinitely big and infinitely far away. That is, imagine a spherical planet that goes around its sun much like our Earth does, but imagine the people living on its surface are infinitesimally small. Then for them the surface they are on is infinite, but up in the sky they can see the sun (and, if you wish, moon, stars, other planets etc.) behaving in just the same way that we see on Earth. This world is quite different from ours, not just in terms of physics but also in terms of mathematics. There are mathematical systems in which the concept of "infinitesimal" makes sense, such as the [hyperreal numbers](https://en.wikipedia.org/wiki/Hyperreal_number) and the [surreal numbers](https://en.wikipedia.org/wiki/Surreal_number), but it is not currently thought that these are relevant to the physics in our universe. (At least, not as far as I know.) But for a fantasy world I think it could make sense. If you don't like nonstandard analysis, you can approach this in a more "classical" way by taking the limit of larger and larger planets. That is, suppose you can create a planet and star as big as you like, while adjusting the laws of physics so that normal-sized people can still live on its surface. (Gravity will have to become weaker, obviously, and the speed of light will have to become faster if you don't want the planet's orbit to be relativistic.) Then imagine a sequence of larger and larger planets, and by taking the limit of this sequence you can consider a planet of infinite size. Of course, you don't have to go all the way to infinity if you don't want to - a planet of galaxy size, or the size of the known universe, would be just as good for all practical purposes, and in some ways is more interesting to imagine. [Answer] As Radovan Garabik said, you don't really need infinite so long as it's bigger than you can travel in a lifetime. So long as you are limited to low tech transport that means structures at star-system scales are big enough. Now, for something that comes close to what you're after and doesn't break any laws of physics (but would require some incredible engineering!) Niven's ring as designed is impossible because it requires materials beyond what chemical bonds can possibly do. However, this doesn't rule out all rings. Step #1: Gather a bunch of stars. These orbit in a rosette, the larger the better but you need a lot of stars. Step #2: Build something akin to Niven's ring but instead of the retaining walls the sides simply gradually climb to the requisite altitude. Note that this ring's distance from the rosette is a bit greater than Earth's distance from the sun, the overall ring is much bigger. Step #3: Just outside this build a far more massive ring. The junction between these two rings is a magnetic levitation system. Think of the habitable ring as a truly enormous maglev train except it's a complete ring so there's no start and end. Step #4: Spin the habitation ring, de-spin the ring behind it. You can get 1g on the inside of the habitation ring without super-strong materials this way as the average velocity of ring + backing ring is orbital velocity for it's distance from the center of mass of the system. Results: You have a land that's perhaps a million miles by a billion miles. The inhabitants don't even realize there are edges as the slope is gradual--to them it's simply terrain that gets too high to cross. You have stars that cross the sky from pretty close to the horizon to pretty close to the horizon. (The bigger the ring the closer to the horizon they'll get.) You can even have seasons by having stars of slightly different brightness. I haven't tried to solve this for possible values, I don't know if you can match Earth's day and year. (And if you can note that it means 365 stars in the rosette!) Beware that the ring is unstable and the rosette is unstable. Without some stationkeeping system the whole thing will end in catastrophe in time. Some possible tweaks: You could have a black dwarf in place of a star. The result would be a day that doesn't happen. If the atmosphere is thick enough (creatures evolved for it won't care, flight will require less wing span) you could even have a neutron star in place of a star. No day but the effects of one of it's jets touching the atmosphere would be an incredible aurora. Note that the jets remain at a fixed orientation in space as it orbits and thus will hit in different locations on different passes. You can't have moons but you do see the more distant stars in the rosette, it will never be truly dark. (The nearby ones that have dropped off the horizon are cutting through so much atmosphere that they won't be seen.) [Answer] Remember that under general relativity, gravity affects light. Imagine an [infinite wall](http://www.mathpages.com/home/kmath530/kmath530.htm) that divides the universe to two halves. Details can vary, but for example if it consisted mostly of stone and was 10 000 km thick, the gravitation would be around the 10 m/s2 seen on Earth. Now, a sun moving above the plane at constant height will eventually disappear behind the horizon, not due to curvature but due to gravitational lens effect. Thus, the world needs an infinite stream of suns, spaced at suitable intervals and moving at suitable speed to provide a day cycle. The path taken by the suns can vary between times of the year to provide seasons. Some of the implications of such world are: * Orbiting satellites are not possible. * There will be regions where no sunlight ever lands (too far to the sides from the path of the sun). * Digging down 10 000 kilometers will bring you into a brand new side of the universe :) * Like @Kolaru mentioned in a comment, due to same gravitational lensing, one would see parts of further-away land above the horizon. Atmospheric refraction will limit the distance, but it would probably seem a bit like as if you were in a deep valley. [Answer] If I was to make an infinite world in an imaginary realm there would be no singular sun. Imagine a blanket of star, similar to our own sky, but with more color variation. Now imagine these "stars" grow and fade in brightness (each in their own rhythm). Some might brighten to the point of a typical sunny day but fade back within minutes. They could flare to brilliance almost instantly or slowly like a dawn. They could fade to pricks of light of vanish completely. They could be different sizes, colors, intensities and positions. Of course there is nothing to say only one would grow bright at a given time. You might have 2, 3 or even a dozen producing light at a given time. As long as the system is backed by predictable math it will close enough to reality that person can understand and follow it, but at the same time it's completely alien. The player might not understand the system perfectly, but your NPCs would usually understand the common and typical behaviors of their stars. This leads to incredibly rich possibilities of events and world effects that go far beyond predictable and highly repetitive day and night cycle. Omens and portents of the pale golden star. Wild celebrations when stars all go dark with bonfires and lights everywhere. Times a year the yellow and the blue stars flair bright for several cycles and the sky is filled with a green light which makes all the plants grow at an insane pace (farmers everywhere could plan crops for these time). Think of a time when a half dozen stars all become super bright and the world is a bathed in blinding light and heat. You could need special protective/reflective gear and have most places would be closed up tight. It would be a rich alternative to the typical "night bad." So short answer... any shape you want, even a simple plane. It wouldn't matter because your light is fixed points. [Answer] One idea is to have your world be a $3$-dimensional subset of a $4$-dimensional space. And your sun (or suns) are regular stars moving along the fourth spacial dimension. We can only see them when they cross our special $3$-dimensional space, and they are invisible otherwise. Since this is a bit complicated to describe, let us reduce this by one dimension, and imagine we want to build a $2$-dimensional world, that is a sheet-world. In this $2$-dimensional setting, planets and stars look like discs. We live on the surface of a disc which is big enough that is seems "almost" flat. What would an infinite world look like? Well basically you have one horizontal line that splits the world into two regions: above the line is the air, and below is the ground. Now what are the suns? Well they are balls (regular, 3-dimensional ones)! We usually cannot see them, but sometimes one crosses the sheet of paper that makes our world, and then we can see it. At first the intersection of the ball with the plane is a very small disc, which makes a nice sunrise (or 'sunswell'?). Then it becomes bigger until most of the ball has crossed the plane, and finally you get a sunset ('sunshrink'?). How and why there are seasons depends on how and why do the suns move, so it is entirely up to you. Maybe the suns stay on the same track and every morning you see the same sun? But there could also be a stream of suns that all follow the same path and every morning you see a new sun. Finally the movements of the suns could be very chaotic, so that some areas stay in the dark for ages before being once again habitable by human beings. If you want to get creative, you could also say that sometimes, suns do not cross our dimension above the ground, but below, melting the rocks around them: that is how volcanoes are made... You could also say that there are many other sheet-worlds: usually they are far away and we cannot see them, but sometimes two sheets come really close and strange things happen, like people and objects appearing or disappearing randomly (or on purpose) by switching sheets. [Answer] So, let's start with a completely flat planar world. This doesn't quite have a "horizon" in the normal sense, as from a suitably high point you can see forever. You can only have a horizon on an infinite world with a cylindrical, parabolic or conic(!) world. Then imagine a single sun tracking across the plane forever on an infinite line. Each place beneath it experiences a single day. Everywhere else gets arbitrarily dim twilight: the sun gets smaller and dimmer as it departs, until it's as dim as the farthest star on the edge of our universe is to us, and then dimmer still, but it never sets. Now consider a line of these suns passing over "east" to "west", at 24h intervals. The trajectories are not entirely the same: each appears slightly "north" of the other, with another sun's track gradually approaching from the "south". In summer, you have suns passing overhead. In winter, you see two suns, but they are both too distant to warm you well. At midnight in midwinter, there are two suns rising and two suns setting, all in the far distance. (Gravitational trajectory of photons or indeed the suns themselves not considered. If you want the sky to be dark the photons have to escape off into space, otherwise a telescope pointed at any angle other than straight up will be able to see ballistic photons from some other part of the infinite surface. It may be easier to have a moving 'firmament' at a fixed altitude which the stars are stuck to or holes in, and which also absorbs stray photons.) [Answer] This is perhaps a similar premise to [Amber](https://en.wikipedia.org/wiki/The_Chronicles_of_Amber). The centre of the universe is the pattern in Amber. Amber is the area around the pattern, and it casts Shadows - sort of onion layers around Amber, such that the 'closer' you are, the more similar things are. Those who walk the pattern are able to navigate through Shadow, by changing one element at a time as they walk. If they walk far enough, they can reach anywhere or anything - but the stranger the 'rules' are, the further you are away from that anchor of reality in Amber. In this way, the central city - Amber - follows a pretty conventional pattern of life. It's medieval ish, and is particularly stable - fires burn, but gunpowder doesn't explode. This means that it's effectively limited to 'sword and sorcery' but at the same time allowing things like our world of Earth (with guns and nukes) to exist. You just have to travel out a distance into Shadow to make it happen. So by being so - there are an infinite number of shadows. As such, an infinite number are habitable, and likewise an infinite number are similar to the sun cycle of the prime.(amber). The futher away you shadow walk, the wierder stuff gets. The premise of amber hinges on a limited number able to travel between shadows - shadow walking being easy ish, but only conferred by the Pattern. Other lesser talents like science, magic and a diverse range between may have a limited degree of ability to shadow travel. [Answer] No need for a sun to travel in a straight line; each sun simply travels along a gigantic circle at some fixed (gigantic) altitude. You could then get a variety of effects by having suns move at different speeds, different length orbits, the orbits drift or wobble around, the altitude varies. An interesting, novel variation on seasons is a region that sees two suns of slightly different orbital periods. During the the mild season, the suns are completely out of sync; each "day" has two periods of light and dark and mild temperatures, and weak winds. During the intermediate seasons, the suns are only partially out of sync; the second sun comes along in the wake of the first, leading to each "day" consisting of one long day period and one long night period. During the stormy season, the suns are completely in sync; each "day" consists of a short, intensely hot period while both suns are blazing, a short, extremely dark period, and long twilight hours that suffer strong storms as the hot, moist air beneath the suns blows into the colder regions. [Answer] Tolkien did fine without a sun in his land. How about a line rather than a point as a light source? If the world is finite east-west but infinite north-south, the line also runs north-south. [Answer] How about an infinite number of Earths orbiting an infinite number of stars? If the ability to walk infinitely on your own two feet is critical, then introduce artificial mechanisms which manipulate physics to keep some or all of the planets very close together (a mile or less, perhaps). Then you simply walk to the point where two planets are closest together, and then jump and float to the next planet (gravity at this point would be near-zero). Something which maintains an appropriate atmosphere across this "gravity bridge" would probably be necessary, or else some kind of space suit for the low pressure and oxygen. The "stars" would have to be appropriately scaled to fit in among the planets without scorching them. [Answer] ## Menger Sponge Earth An idea to provide for an infinite habitable space would be to use a Menger Sponge-like Earth, where the [Menger Sponge](https://en.wikipedia.org/wiki/Menger_sponge) is a 3d-fractal, with a infinite surface area, contained in a cube-like shape therefore resembling: [![Menger Sponge](https://i.stack.imgur.com/KT2iy.jpg)](https://i.stack.imgur.com/KT2iy.jpg) To simulate the cycle of season you could make the Sponge rotate around a source of light (similar to a star) situated in the middle. Of course this will create some areas always in the dark, and others always illuminated, however this is permitted by the question. A solution to this problem could be to add a fractal system of stars, with a new sun placed at the centre of the cube holes in the sponge [Answer] Infinity is really something that we can't discuss while not ignoring the laws of physics altogether. But what if your world is not completely infinite, but just incomprehensibly huge? Imagine a gigantic [Dyson sphere](https://en.wikipedia.org/wiki/Dyson_sphere). I mean a really big one with a radius of 100 million kilometers which has been built by an ancient, but now forgotten civilization. This Dyson sphere is peculiar in that it has inhabitable lands and an atmosphere on the outside. They have built it around one star in a binary star system where the other star is quite a large distance away, but shines very strongly. As the sphere rotates and the stars orbit each other, the surface of the sphere experiences normal day/night cycles, and its surface is 400 million times as large as the earths, which for all intents and purposes of a civilization on the ground can be considered infinite. [Answer] Perhaps you're thinking too much of the universe your characters exist in as a standard universe. Imagine two gravitational forces, one that pulls matter together, then another that pushes everything away. This universe would be an enclosed sphere around a singularity of light. This light pushes everything equidistant from itself. Think of Earth, with a sun in the center of it, then the people would exist inside, being pushed downwards to the ground by the light singularity. Two things can occur now; 1. As time progresses, the sphere grows. This quite literally creates endless space to discover. 2. The sphere does not grow. Instead, if your races dig deeper, they find more spheres surrounding the one they are enclosed in, much like digging underground and finding a huge cave... except that the light permeates the ground as well. I'm sure someone can come up with a radiative light source that, to the human eyes, looks like regular light, but can pass through regular solid matter. I prefer the second solution because entirely new worlds can be discovered. What's normal on one 'plane' of existance may not be on another. [Answer] Charles Stross in [Missile Gap](https://en.wikipedia.org/wiki/Missile_Gap) explored the consequences of remapping Earth on a (practically) endless flat surface called an [Alderson Disk](https://en.wikipedia.org/wiki/Alderson_disk). ICBMs do not work any more, deterrence changes completely... [Answer] You don't NEED truly infinite space (just enough that there is no possible way to travel any appreciable fraction of the distances involved within the life of any individual in the universe you create) but you can have it; there's a lot of world-like structures in Science Fiction that you can take inspiration from 3D fractal structure "worlds" are one but I'd favour Cosmic Macaroni in the name of simplicity. This world is an infinitely long tube that spins around it's long axis to create outward pseudo-gravitational acceleration, the tube is arranged in a very loose spiral, the curvature is invisible from the ground, as is the upward curvature of the ground, due to the scale of the object, but it still creates a vanishing point for the "sun" the horizon is reversed for some observers but it's still there. Sunlight, seasons, weather, etc... are all created magically, using a series of artificial suns (of variable temperatures) that pass down the long axis of the tube (at variable speeds), varying (or not varying) the relative temperature and speed of successive suns passing over a given area creates seasonality or non-seasonality. The local weather cycle works just like on Earth but over much larger surface areas so winds will tend to be stronger and more sustained. The glare of the suns washes out any view of the overarching terrain during the day moisture haze blocks light from fires etc... that would otherwise be visible at night. The other major, and it is really major, piece of magic is in preventing the whole thing collapsing into a sphere under it's own mass. There are several disadvantages to this set up; you can't really do any mining here, there's no material to mine into, you'd just cut out into space which would have catastrophic results for the whole system. You can also eventually walk around a given loop of space within the tube so it's only infinitely large in one direction so to speak, although I think you could configure the terrain (in particular the oceans and mountains) to create the illusion that this was not the case by preventing anyone actually accomplishing a circular circumnavigation instead pushing them into a spiral of travel. Last but not least it is possible that an observer at a sufficient altitude might be able to spot the structure of things if the air at altitude was very dry for some reason. I'd like to point out that this structure could also be build on a smaller scale with less regard for a normal, read Earthlike, appearance without using any magic at all. Pat Gunkel designed it, at the near infinite scale it's called aegagropilous galactotopolis and it looking like a galaxy wrapped in angel-hair pasta. [Answer] Infinite sphere. The simplest answer to replicating all Earth conditions is to replicate Earth's geometry. Either the planet will have to rotate on its axis infinitely fast, or if it's a geocentric universe, the sun will orbit infinitely fast. The sun's energy output must likewise be infinite. One consequence of this (and many other geometries) is that each latitude belt is itself infinitely wide. Thus, it won't be possible to travel to other climates. ]
[Question] [ These creatures have the ability to see all possible outcomes within their vicinity within the next 30 minutes or so. This is not the same as foreknowledge that they have no choice over. Even if they foreknew that they will die the next day, they could not escape it. If they could escape it, it wouldn't have been actual foreknowledge because it didn't actually happen. This is the difference. The ability is that they know what would happen IF they were to do this, and something else would happen IF they weren't to do it. So, they can't predict it like it's their absolute fate, they just know what happens as a consequence of their actions, whether they choose to do something or nothing. It's much like what Dr. Strange did in Avengers Infinity War with the time stone, but with a much more limited range of time. This means that they will know if humans are going to hunt them down in the next 30 mins and are going to hide and are capable of not leaving any trace. Of course they won't, because they can predict what happens if they do leave a trace. It's part of their ability. They can still be found by people who don't have any intention of hunting them down. That's because they already predicted it to be safe. How do you catch creatures like this? Even if people have no intention to catch them and later change their mind will be part of their prediction, so they will choose to hide long before. This is a medieval fantasy setting, by the way, if that helps. EDIT: To answer the comment below about the limitations of their "vicinity", it's wherever they currently are and will be in the next 30 mins. So if they can travel 1 mile in 30 minutes, the predictions will include what happens 1 mile from where they are now. But they cannot see what happens in the other side of the world, where they can never reach within 30 mins. I also see suggestions of 30+ minutes of running or 30+ minutes of crossing traps. The problem with those is that they can already see the 30+ minutes of using precious energy and not seeing results of using the energy. These are wild animals that also need to look for food. Investing in that much energy when they don't even know what for or whether they can finish it is not a very good option for them. They would prefer waiting in a safe place. Some animals in the real world stop trying pretty often. These precog creatures have the advantage of not even needing to try. [Answer] In the end, any predators must be able to outwit these creatures. This would come in the form of planning further ahead than the creatures can see their consequences. Say, for example, one has a nesting point in a landscape where this creature lives. At any point in time, the creature can tell whether they will be trapped within the next thirty minutes. The trick is to allow no possibility of escape thirty minutes before the beast is likely to become trapped. If the creature is restricted to movement on land and is, for example, surrounded by mountainous regions, the creature could be encircled in such a wide radius that it can only tell that a part of their escape is blocked if at all, likely resulting in little to no action. Once the creature is fully surrounded it can no longer escape, and the predators surrounding the creature can slowly advance. --- An alternative method would be drugging the animals with slow poisons. If the river or a source of food is poisoned with any concoction that has no detectable effects until thirty minutes have passed (for example a slow-to-digest food containing poison in the centre), the creature will realise it's fate has been sealed. It may try to escape in a panic, and skilled hunters will be able to track it down. --- A third option, assuming the creature loses this ability while asleep, is simply attacking by night (or by day if the creature is nocturnal). If the creature experiences sleep paralysis it will be unable to react should it be woken. [Answer] You could actually catch it with endurance. A theorized hunting strategy used by early humans, to catch prey that was faster and more maneuverable than us was to simply keep tracking it. Sure it runs away, but give it 10-15 min and we'll have found it again, leaving the prey with limited to no time to rest, eat, and drink. Eventually the prey will be too tired to run or fight back and easy to catch / kill. As an example, a cheetah can run 112 km/h (70 mph), but only for a very short time before it needs to rest for ½ hour. That's at most a couple hundred meters every ½ hour, easy for any human to catch up to it before it can move again. Doesn't matter if the animal knows you're coming, it can run if it wants, but it'll tire long before we do. [Answer] # Make Them Want It As you mentioned in a comment, if the creature is caught then they wanted that. So... make them want it! This could be achieved in a number of ways of varying difficulty (you don't mention if they walk, run, slide, fly, crawl, etc), but in general here are some ways of making a creature want captivity: * Destroy their food supply. If they foresee that they're starving, but being captured means instant access to food and care (at least for 30 minutes), then out of desperation to survive they'll eventually give in. * Introduce threats and rewards. Make captivity look great. Make their current live look miserable. Introduce more predators, toss diseases into the water, whatever. This is important: precisely because they can see all future outcomes, the more of those outcomes look miserable, the more stressed and desperate they become. Just because you can see the future doesn't mean you stop having emotions! For rewards, Whatever the creature wants, offer it to them. Food, pampering, their own internal heated cave. The more captivity looks like a delicious, forbidden fruit, then over time the stress of day-to-day life will wear them down until they finally try out that nice offer. * If sentient, brainwash and send captured creatures back. Having another creature go back and recruit their friends / family into your "community" is a great way to build a cult.... er.... "recruit sentient, foreseeing creatures to submit to you willingly" * Get them high... and addicted. Leave their preferred food supply around with some sweet, delicious, addicting drug all over it. They'll foresee the pleasant feelings of that first high - that might make them want it even more! Keep giving it away freely. Once they're clearly addicted, start restricting supply. Eventually they'll cave in because being in captivity with their addiction met will be more desirable than the sobriety of their normal lives. [Answer] The simplest option I can see is a modified strategy for poisoning rats. See, with rats there is usually one that goes and tries any food before the others join in - if the food is poisonous or a trap, only one will die. So, in order to poison a lot of rats, a slow release poison is used - one eats, the others assume it's safe and also eat. Later the poison kills them. How can this be used against a precog creature? It can see a short time into the future, so if it saw it eats some foods and then falls down (dead or unconscious, depending on how people want it), then it won't eat the food. But if the agent in the food takes longer to kick in, say, about an hour, then by the time the creature knows what would happen, it would be too late. You need a slow acting sedative or poison. Second, is delivering the tainted food. You can "hire" somebody to just drop it off near where the creature lives. You could give it to a child and say "go put this here and come back" or enlist a passing traveler - anybody, really, who woudn't necessarily know the plan. So, even if the precog creature can see that somebody is going to drop off food, it would also see they won't linger, so it would seem safe. Finally, you need to go and collect it. I assume the hunters have some knowledge of where creatures like these dwell and where they like to stay. If it prefers caves, they'll have to check caves, if it prefers to hide in holes in the trees, that's their target, etc. But the hunters have to go out about 2-3 hours after the food is delivered. The reason is to avoid the precog window - the sequence of events is roughly the following: 1. You get somebody to leave the tainted food and get out of the area. 2. Creature would know somebody is going to drop off some food and leave. 3. (T-0) The drop is done. 4. (T+n) Creature eats the food. The agent starts to slowly act for about the next hour or so. 5. (T+n+30) Creature now knows it is about to fall asleep or die (whatever the agent does). If it tries hiding, it has about 30 minutes left. Even if it doesn't, if it sees somebody coming in to collect it, within that timeframe, it would hide even better and erase their tracks to the best of its ability. So, if it doesn't see anybody coming for it using its precog ability, I assume it would still try to get to something it thinks is a safe place. 6. (T+n+60) The creature is unconscious or dead. So, that's why you want to send the hunters to collect it later - after it's incapacitated and cannot use its precog ability. There is a small time factor that's uncertain - the n represents the time from the drop to the creature eating the food. It might take two hours for it to feel peckish enough, and you can't have people with the intent to hunt it around until after it has eaten and the poison has taken effect. You can minimise this n variance by using its precog ability against it - it would know that there would be some food dropped in advance, so if you know when it usually eats, you can time the drop around that time. And since it would see who does the drop, where, and how, as well as how to avoid them, it might even be waiting in a safe place and eat the food immediately after the courier is out of sight. To help get this outcome, you can provide food that the creature likes and it's also a favourite for other creatures around. The precog would prefer to get the food before the others find it. I also make the assumption that the hunters have enough knowledge to dose the poison correctly to act not too fast and not too slow. The hour mark might vary but they should generally be aware by how much. If you cannot really control n effectively, then you might need to send out the hunters after half a day or a full day. In that case, if you want the creature dead, that should be fine, but if you want it sleeping/unconscious, the poison might need to be stronger once it takes effect. At any rate, what you're left with is the hunters going out and checking usual hiding places for the creature. Caves, tree trunks, whatever. Since it didn't even foresee anybody coming for it, there might even be tracks left to guide the search effort. [Answer] Make a trap that looks like a safe and inviting place to sleep, and design the trigger so that the trap will not spring until the creature has been sleeping for at least X amount of time. [Answer] Do it like computers do. You know why we can't defeat them in chess anymore? Because even if you remove all heuristics and leave only brute forcing algorithms, they are still able to see thousands of moves ahead. They will take you along a route that ends with you losing. So the creature can see thirty minutes ahead - plan for a trap that will ensnare them in days. Build a tall fence in a very large area around them. I do mean very large area - like a blocks-wide fence. Then start building inner fences. All the creature will be able to see at some point is that they get captured in any future. [Answer] Encase the entire planet in a shell of any material of your choosing. Congratulations, you’ve just caught them all in the world’s largest pokeball. Ok, that was a joke, but it serves illustrative purpose. You set up a ring of people/machines/fences way outside their perimeter and then you have them caged. Now you just start reducing the size of the ring. There are dolphins that use this strategy with fish; humans have used it for hunting also. Eventually the cage is small enough to pin them down. As the planet example shows, there’s always some initial cage size large enough that even if your critters know it is coming, there’s nothing they can do. [Answer] I know that this question already has an accepted answer, but I just can't help weighing in... 30 minutes of precognition is a truly terrifying thing... and if these critters have had this ability for more than a few generations, they will have evolved to take advantage of it. How would they evolve? Surely precognition means that they don't have to? Well... everything that reproduces itself evolves, and a critter like this will evolve to give it the most valuable things it could possibly have: Options and offspring. Regardless of its starting point, whether that be a mouse or a moose, a lizard or a lion, once it gains precognition, it will evolve to become more of a generalist, and it will become smarter. A mouse would evolve to become bigger, stronger, smarter, and better able to fight. A lion would probably become smaller but smarter, no longer a creature of brute strength, but one capable of far more subtlety. A moose would evolve to be smaller and smarter, and a lizard would evolve to be bigger and smarter. What if it's a bird... say, a duck? It too would evolve to give it more options. Obviously flight is a major option for a bird... but a precognitive duck would likely evolve a sharper beak and bigger talons alongside its bigger brain. The most terrifying option for this creature's progenitor would be some sort of monkey... they're already reasonably smart, so they would need only a moderate body size and sharp claws and fangs. Of course, this critter would continue to evolve its precognition. It may have started out as flashes that extended only a few moments into the future, but that would be enough to give it a significant advantage, and if it has evolved to be half an hour, that suggests a considerable amount of evolution already. So... whatever the creature, it will likely range in size from a kitten to around human-sized. It will likely have sharp teeth or a sharp beak and claws or some other natural weapons like hooves and horns. It will likely be - or at least be on its way to becoming - an omnivore. If it's non-precognitive ancestors were [r-strategists](https://en.wikipedia.org/wiki/R/K_selection_theory), it could be well on its way to becoming a K-strategist, as precognition makes for great parenting. With an entire half-hour of precognition, these critters wouldn't be particularly rare if they had any amount of evolution behind them, but they would be rarely seen. Knowing when you're sufficiently well hidden is a great advantage. So... if a critter like this was to be encountered by humans, whether modern or primitive, it would quickly gain a reputation for being elusive, since not being seen by humans is a good survival strategy, as well as gaining a reputation for being very dangerous - if the critter can't hide, and can't run, then it had better put up the best fight it can. These critters would likely be fairly aggressive too. Humans, if sufficiently fit, are persistence hunters par excellence. Few if any creatures that have ever evolved can match a human for the ability to cover ground rapidly over long distances on foot. So, if one of these critters was to be seen by a human and pursued (and couldn't just fly away), it would likely end up badly for the critter... which is why it wouldn't likely run at all. It may not be able to foresee its death at the moment it considers flight as an option, but it would be able to foresee having run for an entire half-hour, and it could also consider other options, such as fighting or hiding. If it knew that hiding would fail, it could put up a very good fight indeed. If it came to a fight between a human and one of these critters... or even multiple humans against one of these critters, the humans would want to be armoured like knights in full plate armour. The critter might be the size of a rabbit... it might even have evolved from a rabbit... but fighting it would be like fighting the [Rabbit of Caerbannog from Monty Python and the Holy Grail](https://en.wikipedia.org/wiki/Rabbit_of_Caerbannog)... without the option of lobbing a grenade at it, since it would be able to foresee that, and adjust appropriately. With halfway decent natural weapons, every member of this species would be able to employ them with a skill in excess of that of any master martial artist. Humans are thin-skinned, and these creatures could unerringly target vital points, dashing in, dodging any attempt at blocking or attacking made by the humans, and then leaving wounds that just happen to open major blood vessels, or disembowel the hunter, or one of any number of other disastrous occurrences. Even if the humans were wielding firearms, the outcome would likely be bad for the hunters... the critter would likely recognise firearms for what they are, and would either dodge every shot, or potentially attack in such a way that the humans would shoot each other. Finally, stealth is unlikely to work against one of these critters. Yes, it may work defensively, but offensively? It'll foresee you coming half an hour out. So... how can humans capture such a formidable foe? There are suggestions that they could be fenced in... but if the area about to be enclosed is insufficiently large to accommodate the critter, it's likely to be smart enough to realise, and the odds of it breaking out of the enclosure increase to a near-certainty just prior to the effective completion of the enclosure. Regardless of any other strategy, fighting one of these critters is a pretty much suicidal tactic for any single or even multiple would-be hunters. Then there's poison or drugs... these have a pretty good chance to work if they take effect slowly enough, but a critter like this is likely to have evolved to be suspicious, and like a rat, is unlikely to simply chow down on any free meal that has no reason to be where it is. Additionally, if one critter samples a bait and succumbs, any other critters who had been considering sampling it will avoid it, and will likely recognise the danger in the future, since they can foresee what something will taste or smell like without having to actually taste or smell it unless it doesn't seem dangerous. However, the most likely option to 'capture' one of these critters is domestication. As shown, hostile intent toward one of these critters is not likely to end well at all, but their precognition is likely to make them more domesticatable than their precursor species. If approached in a friendly manner, one of these critters would be able to foresee any future hostility, as well as future enticements. Their precognition would give them a confidence that other creatures their size would not possess. While it might begin cautiously, only accepting a tiny amount of the offered treats until it was sure that it was innocuous, it would likely be relatively quickly domesticated. However, it would be inadvisable to attempt to harm the critter once domesticated - it would still foresee the attack coming well in advance, and either hide, run away or preempt the attack with one of it's own. You needn't worry about your kids hurting it - it would know when they were planning something, and would be able to avoid or avert it... most kids are smart enough to realise that when they so much as contemplate doing something that the companion critter might not like and they then get growled at, it isn't likely to work out well. There would be considerable advantages in domesticating such a critter. The critter gains an easy, plentiful food supply and a safe place to live, and in return is likely to be an excellent guardian, protecting its human companions and their property. In a modern paradigm, if you had a companion critter, you would be well advised to travel with it... it would be able to foresee potential accidents well in advance, so if you're driving and your critter companion starts to get insistent that you stop or divert, doing so could save your life. Critters would be welcome on board aircraft, since if they began to act up, it would be a strong indicator of an upcoming disaster, and at the very least, they would allow the pilot the time to prepare to ditch the aircraft as safely as possible. There could be other benefits too... imagine that you're browsing in a shopping mall, and your companion critter suddenly leaves and begins to threaten - or simply slaughters - a harmless-looking guy with a backpack... but when the cops investigate, they find that the guy was a potential suicide bomber or gunman, and the backpack was full of the guy's weapon(s) of choice... [Answer] How to catch creatures that can predict the next few minutes? I'm glad people reference The Golden Man but some of them are missing a point about why he "wanted" to be captured. Sure he wanted to live while all other choices killed him within 30 minutes but this leaves a fairly obvious alternative that's a bit glaring in it's absence. *Figure out a trap it won't notice until it's been in it more than 30 minutes.* [Answer] These creatures can predict the future, but they cant necessarily leave no trace at all. TL,DR: you have to limit the options the creature has to fight or escape, and make use of your own capabilities versus those of the creature to catch it. Just because the creature knows the future does not mean it can pull off anything needed to get to safety! Like climb sheer cliffs or run faster or dodge arrows perfectly. I can know perfectly well when someone will fire an arrow and where it'll travel but that does not guarantee my safety. Long version: Imagine these creatures stuck on a large flat plane and he knows a human will arrive to hunt him soon. He could hide in the sparse foliage but the human has seen some of his tracks and is following it so the creature's only choice is to run. But no matter how long or far it runs the human is a HUMAN, endurance and constantly following a creature on open plains is kind of its thing. So all options lead to the creatures death in many cases. This is key: limiting the options. Then there's smart hunting. If you know the creatures limit you can set a timer for a bit more than half an hour. In that half hour you start feeding it and caring for it, making the creature come to you. Naturally it also sees options that if it suddenly runs the human might harm it, but why would it run it sees a full 30 minutes of care and food! But after 10 minutes of being fed and cared for the creature sees the human will suddenly kill it... except that the creature is now in the hands of a human looking for the moment the creature will run, and at that exact moment the human will strike. The amount of options the creature has are now limited, and even knowing the future does not allow the creature to suddenly pull off a tripple handstand with a twist to get away as it is still limited in its capabilities. So the human has leveled the playingfield. While the creature sees the things it has to do to escape, it does not necessarily mean it can successfully do them. [Answer] It doesn't mean that if a creature has perfect knowledge of the future it is also able to choose its most favorable path or that a favorable path actually exists. (I will not elaborate on paradoxes, as those could violate the premise of perfect knowledge) You have to make sure no favorable paths exist for the creature. You could make an attack on the creature where you eliminate all favorable paths, making a trade off between collateral damage and accuracy, but accuracy probably requires more patience. Collateral damage: Dropping a bomb with a large enough blast radius doesn't allow the creature to run. As soon as the creature becomes aware the bomb will fall, getting to safety is no longer an option. Accuracy: You don't even need a blast radius spanning the total area the creature can run to in 30 minutes if you can accurately hit anything within that area with a bullet at any given time. Just wait until the creature is deep enough inside the area and then start a timer of 30 minutes before actually striking. If you want to catch the creature rather than kill it, you could replace the bomb with a gas cloud that would render the creature unconscious, making it unable to resist you capturing it. --- Depending on the setting you could add flavor on this idea: * A bio-weapon could be created for that specific creature while being harmless for others. Then it could be detonated in a large area without causing collateral damage. * An advanced AI could target an entire area while having the ability to accurately hitting any single target. * A hunter could track the creature for a long time before actually striking. The creature would only see actually striking as harmful, so by the time the creature is aware of any danger, there is no escape possible. * You could start a big fire that fatigues the creature trying to escape it. The most favorable path seen by the creature is being rescued by you instead of dying in the fire. By the time the creature realizes it is actually being captured near the edge of the fire, it would be too weak to run away or resist. [Answer] ## Just be Nice to It Most animals will never trust a hunter enough to let him put it in a cage because they don't know what the hunter will do next. If this animals sees this hunter giving it food and water and scratching it behind the ears for the next 30 minutes, then it will gladly run straight into the hunter's arms. The hunter does not even need to track it down. The animal will track down the hunter. It will foresee that hunter will bring it to a comfortable place where it can sleep in safety, it trusts the hunter because it "knows" it can trust the hunter. Then, it will wake up an hour later realizing it's trapped in this comfortable room about to be slaughtered with nowhere to go, nowhere to hide, and no way to fight back. [Answer] 1. Create a dependency loop which those creatures wouldn't be able to resolve. That is, set up a situation which would involve two such creatures. Such that the best course of actions for creature A would depend on (yet indetermined!) action chosen by creature B, and the best course of actions for creature B would depend on just as indetermined action of creature A. In other words make the future depend on two unpredictable factors (actions of creature A and B), while leaving one of this factors out of control of each creature. --- 2. Choose the weakest Do they have full control over this ability the moment they are born? Supposing they need some parenting and training to develop this ability, hunters could try luck with the untrained ones. On the same note, this ability could diminish when a creature is sick. 3. Embark on a long programme to domesticate them. Start feeding them, kind of thing; no strings attached. They will see no direct immediate danger, but they can't read your mind to see how it's going to change things in a few generations. Your question doesn't set any time limit, after all... [Answer] A very large circular fence that slowly reduces in size ]
[Question] [ Airships are awesome, but making them realistic while retaining the awesome factor is hard due to how relatively little weight they can realistically carry. I was thinking about ways to mitigate that and came to the idea of introducing some Unobtanium-like mineral that produces lift on its own, meaning it has negative mass. Maybe it's magical, maybe it's just an exotic form of matter, but there are deposits of it here and there in the rocks and people discovered its properties. It is relatively rare (does not occurs in dense enough veins to cause Avatar-like floating islands) but spread out evenly, with me also thinking that it might make it easier to explain certain quirks about the layout of the world (It can help to keep massive vertical cliffs of the setting from crumbling and eroding away). So people would employ the material in the hydrogen-filled airships to greatly reduce their weight. Now though I imagine such mineral would find its use in other fields of the industry probably, which has risks of transforming the society and technologies in unpredictable ways, making them less "victorian" and "steampunk", which would be an unwanted side effect of the solution. How can I prevent the mineral from being useful outside of airship construction, or at least not useful enough to have a significant impact on the civilization and technology? [Answer] A solution could be to make this material unstable. It's possible that this material requires special containment when it's grouped together, rather than spread through the ground. This could make it more difficult for use in things such as shipping containers, heavy weaponry, small-scale vehicles, etc., if the containment isn't something that would be practical to put on a box or a machine gun. [Answer] It only works at high concentrations Like fission, you need a minimum amount of this material for it to generate lift power. Gather a cube meter of this material and it would barely lift itself; but gather one thoudans cube meters of it and it will be able to lift some kilograms, and so on, following some exponential rule, so that when you have the same volume as a Zeppelin, you can lift some thousand tons of material. Since you need a big volume of it to generate a decent lift, it is useful only for some not-size-constrained purposes, such as big airships, but would have otherwise limited uses for basically all other purposes. [Answer] When the material is “grounded”, it doesn’t give lift. They haven’t been able to figure out if it is some kind of static charge or a magic connection to the earth, but if it is connected to the ground by some sort of solid matter, the anti gravity effect doesn’t appear. Edit: The grounding effect isn’t immediate. It takes several hours to lose all lift, so you can dock briefly. It also take some time for the effect to “charge”, so you do need the full airship structure to initially lift some of the material, then you can take on more of it, until you reach the desired lift strength. The “charge” time also prevents use as projectiles or the like. [Answer] Something similar happened in the real world. By the end of the 19th century people were drinking uranium-enriched water as a health elixir, because it would supposedly kill harmful microbes in your body (never mind it kills the useful ones such as your gut flora as well, before also killing you). Marie Curie discovered a lot of the physics behind radioactivity but she only found out about the poisoning when it had already happened to her and her husband. Prior to that she would carry around pieces of radioactive material to show to other people, because the glow was beautiful. Even as recently as the 1980's... Two scrap thieves in Brazil stole some Cesium-137 dust from an abandoned hospital. One of them used it to make an impromptu glowing tattoo on his own stomach. Industrially uranium could be so useful because it is very dense. It could make for a better shield against X and gamma rays than lead, if only it were not a source of radiation as well. It could maybe be used for construction too, but it would make for a very unpopular building. Nowadays the only well known uses for uranium are power generation, material for tank armor and terrorism. --- So take a page from uranium and make your own unobtanium radioactive. Make it even more so than uranium for a kick. Surely people won't wish to build everyday usage devices with it. [Answer] Frameshift: Your mineral has no antigravity properties. Rather, it is a nongravity item. Metal alloys containing a sufficient quantity of the mineral become unaffected by gravity. You build your airship out of such metal. The lifting comes from hydrogen or helium as normal, it's just your lifting capacity is available for cargo rather than using most of it to simply lift the airship itself. You can use it to build other lightweight things but how often will that be important on the ground? Extra-light versions of many things exist on Earth, yet rarely see much use outside the sporting world because the improved performance normally isn't worth the cost. I hike so I see some of this in action. Go to REI and you'll find titanium versions of some everyday items--but you're not going to find them in ordinary stores. The titanium versions are considerably more expensive than the household equivalents, only someone who really cares about weight (someone who is going to be carrying that item for many miles) will pay the premium. [Answer] The material is sort of self limiting, in the sense that if too much is collected in the same place without enough mass to neutralize it will end up sending into space the hoarder. This will be quickly realized as soon as someone starts to hoard it and disappears in the act, and the needed mass to ensure safety will be what prevents widespread usage. [Answer] ## Decay properties: Your unobtanium emits heat and decay particles as it decays. If one of these particles connects with another particle of unobtanium, it causes a decay reaction that emits heat and more decay particles. Fortunately, your unobtanium converts to a gas when it gets warm. Deposits are found wherever volcanic activity allows the unobtanium to condense. So ores co-mingle with materials like gold. As the unobtanium gas fills a balloon, the density of the material drops below the level where the decay particles cause an uncontrolled chain reaction. As long as the unobtanium is kept warm, it keeps the balloon floating. As it cools, perhaps it forms a precipitate (unobtanium carbide?) that falls(?) like snow in the balloon, condenses at the bottom (or condenses on the ceiling...), and (often) heats up as the decay accelerates. The goal is to keep it from decaying, since it is too valuable to let it break down. it can't get incorporated easily into materials (except at levels where it is not very useful), and your air ships will need constantly burning steam engines to keep the stuff warm. All that steam power WILL allow your ships to have huge propellers, or possibly use steam rockets for propulsion (if a constant supply of water is available). They'll look less like the Hindenburg, more like the Titanic. I think the bigger challenge is to get the airships back DOWN. Perhaps the material reacts with elements in the air as it cools, binding more and more mass as it reaches room temp and achieves neutral buoyancy. If so, the material is possibly harvested from the sea, as the volatilized unobtanium would settle to the ground and often float on water like amber. Perhaps it's effects increase the hotter it gets. Or maybe the airships are also hot air balloons, using heat for lift, and unobtanium for canceling the weight of the vessel. Ammonia is a lifting gas that can be condensed, allowing descent by condensing the gas. It's not a strong lifting gas, so it's usefulness in airships is limited. But unobtanium does the heavy lifting, so your lifting gas mostly needs to allow going up and coming back down. Lighter lifting gasses are cheap enough that they could simply be vented or (for hydrogen) burned. [Answer] It's a super-strong lattice, but it still needs to be evacuated to generate lift. In its natural state, it's soaked up with air, so it can't lift anything. To actually use it, you need to: find it and isolate it, as any impurities add weight; envelop it in material that doesn't allow the passage of air; actually remove the air. You can just wrap raw vacuttice in leather, pump hydrogen through it, and it will lift for a couple of minutes, before air seeps back in. Unfortunately it turns out that the hydrogen is kinda expensive and it's cheaper to just hire a couple more warehouse haulers. Just driving hydrogen through it won't remove enough air. You need to go big. Airship docks have specialized chambers that can "recharge" vacuttice pods by leaving them in hydrogen atmosphere for extended periods of time. Cheap pods need frequent replacements, expensive pods will power an airship for days or even months, and simply pumping hydrogen into the lifting body may even be able to keep them running indefinitely... and if you use an unusual type of pods or need to replace more than the port has in stock, you better have your own hydrogen chambers and/or expect downtime. Whether vacuttice has actual anti-gravity properties, or simply acts as a physically plausible rigid vacuum remains a mystery. Atmospheric density measurements suggest they have to, but the general public remains skeptical... [Answer] ### Maybe it is used in other applications, to allow impractical steampunk contraptions to work. Often, in many steampunk works, there are massive mega-trains, giant steam-powered robots, and the similar such devices that would be completely impractical to build in real life with that level of technology. Perhaps the mass-reduction effect of this unobtanium material would allow these sorts of constructions to function as well, similar to how it allows massive zeppelins to function. The difference between a massive zeppelin and a mega-train is perhaps in the ratio between the mass of the vehicle and the quantity of the unobtanium material used in its construction. In very small amounts, perhaps it would even allow for steam-powered prosthetics or suits of power armor! [Answer] Refining the Mineral Is Costly One way that you can seriously restrict the applications of the mineral is by making it highly difficult to refine into a usable form. This in turn would mean that its applications would be limited to those that get the most bang for your buck, like using it to give additional lifts to airships which can transport both people and cargo in ways land and water based forms of transport cannot. No need to build a railroad through hazardous mountain ranges when you can just float over them and get from Point A to Point B in much less time. The Lifting Properties Are Not Automatic In order for the mineral to generate lift, it has to be subjected to some kind of effect. This could be changing its temperature, running an electrical current through it, or exposing it to a particular wavelength of electromagnetic radiation. On its own, the mineral just sits there and is actually quite useless. This would require airships to have some kind of complicated system in place to control the lifting properties of the mineral. One example of this kind of idea is in the Anime series Escaflowne. In that story setting, airships were built around these big rocks which have heating pipes connected with them. To raise the airships, they had to increase the temperature of the stones and if the heating system had a problem, the airships would start to sink toward the ground. You could go for something similar. (It'd also work as an allusion to how hot air balloons work by increasing the temperature of the air inside them.) The Mineral Is Dangerous to Mine If the mineral is highly toxic, then mining it will seriously limit how much of it can be acquired. If the miners require tons of protective gear to stay alive while they collect the mineral in its raw form, that's going to slow their work speed considerably. Another issue could be that, if its lifting properties are innate, then its applying a lifting force to the earth and stone around it. Thus, when its removed, that force is removed, which means you have a higher chance for tunnels collapsing. Alternatively, the mineral could be found alongside other toxic minerals, like how talc may be found alongside asbestos. Or the mineral could be volatile in its unrefined form, so there's a risk of it exploding or discharging electricity or something along those lines. The Mineral Has No Other Applications This mineral's unique lifting property is the only thing it has going for it. It's totally inert otherwise. It won't combine with other materials, the way different metals can be combined to make alloys, it's not very durable, so it can't be used to make things like structural supports, tools, or other useful things. It literally only has one application - making things float. If you place restrictions on how well it can do that, such as by requiring it be affected in a particular way, then you can keep it from becoming too overpowered quick effectively. The Mineral Is a Little Too Good At Lifting Things If the mineral is too good at making things float, like causing them to float so high that they can escape the planet's gravity, then the mineral has to be used in very conservative amounts. This could be why the airships use other kinds of lift, such as gas, in addition to the mineral. They need to be able to reduce the total lifting force for emergencies, so they use gasses that can be vented instead of relying entirely on the mineral. The mineral reduces how much gas is actually needed to get sufficient lift but is unable to provide enough lift to get the airship far off the ground on its own, but will ensure that the airship will never crash into the ground, either. Your airship is "unsinkable," in a sense, but also not in danger of leaving the atmosphere. [Answer] It stinks. Tanneries have nothing on the odor of your airship mineral. Brimstone is pleasant in comparison to the wretched greasy stench that radiates out from this stuff. The Bog of Eternal Stench is probably the first known source of this mineral. NOBODY wants to be around it. The very best place for your mineral is a thousand feet up and drifting away. The airship crews swear you can get used to it. The rest of the world disagrees. [Answer] The material by itself doesn't have negative mass, but rather "gravitational frame lag", requiring large machinery to make it produce lift. Specifically, the effect of gravity on this material "lags" behind it's physical position. For example, if you hold a chunk of unobtainium, it would appear to be a regular, if dense, chunk of ore, but if you flip it around, it briefly "falls" upwards before it re-normalizes to the new "down" direction. This allows the ore to exist because on geological time-scales, anything with negative mass would've long migrated to the surface and then flown off into space. This material is used in airship construction by building long, massive cylinders out of it. When the cylinders are spun at just the right speed, the "lag" causes their average gravity to pull upwards, therefore producing lift. This means an airship equipped with these large spinning masses needs to burn a lot of energy into turning them, thus eliminating thermodynamics problems. Additionally, the energy to spin to lift conversion ratio is so bad that when grounded, there is basically no application for these things as anywhere there's enough power to spin one fast enough to produce lift, it would be much more efficient to simply use an electric (or similar) motor to accomplish the same task. Eg, why build an unobtainium elevator when an electric one would only one tenth and be far more efficient. [Answer] It generates lift, but is only economical in large quantities. Pick an arbitrary "break even" point. Let's say it takes 100 kg of unobtanium to provide 100 kg of lift. Beyond 100 kg, the lift increases, below 100 kg, the lift per kilo of mass decreases, so that to provide, for example, 1kg of lift takes 10 kg of unobtanium, 1 g of lift takes 1kg of unobtanium, and so on. But 1000 kg of unobtanium will lift 100,000 kg. This would make it useless for small scale applications, but invaluable for large scale applications such as airships. Depending on where you set the break-even point, it would be more or less economically viable for small scale work. At some point, you would reach a diminishing returns point where adding more unobtanium would generate less lift per kilogram, until you would have to add a prohibitively large amount to get a small amount of lift. The reasons for this would be left to the author to determine, but I put it out there as a way to control the usage of the resource. The Hindenburg weight about 200,000 kg, so would take around 3000 kg of unobtanium to lift. 500,000 kg of mass would take 10,000 kg of Un, 600,000 would take 20,000, 1,000,000 kg would take, say 100,000 kg of Un. At that point, Un is providing only 10kg of lift per kilo. [Answer] Just make it a negative-weight gas, so you have to fill the airship with it. It loses its negative-weight property if condensed to liquid or solid. This pretty effectively prevents any uses that don't involve giant balloons. [Answer] One word: volatility I like some of the other answers but they get too deep into physics. This is a spin on the "too much makes it go up and up" answer: A small amount of "unobtanium" in an area does nothing. A medium amount of "unobtanium" in an area makes something buoyant. A large amount (or "too much") in an area makes big boom. The material interacts with itself in such a way that the interaction creates the "energy" for bouyancy... until it creates too much and a chain reaction occurs. Not enough material? Might as well be talcum powder... too much? might as well be C4. just enough? creates the means for floating ships. [Answer] Option 1: Required significant refinement and is hard to handle The mineral works "as advertised", but only when refined to 99.999% pure. This will increase the value and reduce the availability. Also, once refined to the appropriate purity a volume of xxx (chose an amount that works for you) is so functional that it requires excessive procedures to handle safely (i.e. to keep it from flying away). Handling options might include: 1000lb gloves, massive containment (1000lb of steel) vessels. To put it into operation, the airship is constructed, then weighed, then multiple xxx volumes are added until the airship achieves the appropriate buoyancy. Option 2: Requires significant refinement and only works under 'high' voltage As before, must be refined to 99.999% pure. This will increase the value and reduce the availability. The lift is generated by applying a large electric current which requires a large, onboard dynamo (generator). The size of the dynamo and the volume of fuel to operate the dynamo are the limiting factors. You might add, there are only steam engines to run the dynamo. [Answer] You could just monopolize it. Have it be only obtained through an invention only a certain company has and without it, extraction of said mineral will make its properties decay severely so that only a company that uses it for spaceships and stuff related to it can only obtain and use it. [Answer] Super strong carbon deposits In your world, for whatever reason, there are some bacteria that deposit graphite, a special carbon weave that is incredibly strong for it's weight. It has electrical properties, which might actually be used in yoursteampunk setting, but mainly it would be light and strong. The bacteria just spread out and leave the carbon as a waste products, with some enzymes organising the carbon onto a graphite weave structure. The advantage of this is that people don't manufacture or mine it, but just have areas where a limited amount is made, limiting the overall supply. There are several kind of these bacteria, depositing different kinds. Some are more useful than others. Some just have the weave, while others leave nanotubes, while yet others leave less well constructed weaves or the like. Because it's lightweight and strong it can be used in many industries, but mostly in a way that could advance tge steampunk tropes. Airships are a prime example where you want lightweight strong materials. Several layers can form the gasbag with a good weight reduction, while it can help suspension of the carriage among other things. The carriage can be made with much less metal, reducing the weight. Conclusion The overall advantage is the limited supply, making it difficult to expand to huge industrial sizes for everything. At least until the processes to make the material/understand bacteria and cultivate them is fully understood, which can take a long time. It would be used mostly where it makes most sense, one of which is air travel. It doesn't exclude to be used in other areas, but that can be advantageous for the steampunk trope. The potential for other industries and moving electricity efficiently can be a boon, not a detriment. [Answer] # Antimatter [It is an open problem in physics if antimatter is gravitationally attracted or repelled by matter](https://en.wikipedia.org/wiki/Gravitational_interaction_of_antimatter). Most physicists expect that they are attracted, but there still could be that this is not the case. If antimatter is gravitationally repelled by matter, then this is what you're looking for. Antimatter is very hard to be created in any sizeable quantity and still harder to be stored for long time. Also, large quantities of antimatter would be a really dangerous thing to handle. So, imagine an apparatus that stores large quantities of antimatter in a way that the quantity of antimatter stored is significantly superior than the quantity of matter used in its storage compartment and that doesn't just annihilates and explodes in femtoseconds, but instead can store the antimatter safely for years. It would have a significantly negative weight and would be strongly repelled by Earth's gravity. The apparatus is extremely complex, bulky, heavy (when its storage is empty), expensive, fragile and dangerous, but it enables your civilization to do something very important: It drastically reduces the cost and the fuel needs for launching stuff at the space! However, its shortcomings makes it be practically useless for anything other than that. [Answer] It only creates negative lift when an electrical current is run through it. Creating an electrical current at the technology level of your world requires an enormous steam turbine, with commensurate weight increases of water tanks, coal, crew. The only time this whole equation balances out to create useable lift is on an enormous airship! [Answer] It is not just mined. The mineral is transformed by an exotic interaction with high energy cosmic rays. Bringing it into space would be too expensive, so some very light, unmanned, airships will have to keep it for a time at a height of 20 thousands meters or more where cosmic rays are more intense before it can be used and the process is very slow. [Answer] # Use Cavorite H. G. Wells' The First Men in the Moon introduces a reclusive physicist by the name of Cavor, who is working to develop an alloy that can shield against the effects of gravity. He successfully creates the material, dubbed Cavorite. In an early part of the story, a sheet of Cavorite is processed prematurely, and it causes the column of air above it to become weightless; which causes a powerful updraft as the non-weightless air applies enormous pressure on the column; the Cavorite, also weightless, hence shoots itself into space. The main characters are able to devise a system of windows that can negate the shielding that Cavorite applies, which enables them to make a steerable ship. Cavorite is also featured as a plot point in Alan Moore's graphic novel League of Extraordinary Gentlemen, where it is used to create an aerial warship which is unleashed in the climax of Volume I. In it, only a small amount of Cavorite can be used as the power source of an "engine" that provides lift for the enormous ship. I highly recommend giving League of Extraordinary Gentlemen a look for the aesthetics alone; its setting is that of an enormously amplified Victorian era where late-19th and early-20th century contemporary speculative fiction is real. The movie, on the other hand, is bad and has nothing to do with the comic. When Cavorite is used without a way to control the shielding, it causes air to escape the Earth's atmosphere. If you had a large enough sheet of it secured to the ground, then given enough time the Earth would be rendered airless and hence lifeless (or not, more on that later). Furthermore, the force applied by atmospheric pressure on the now-weightless air has the potential to be destructive on its own. Ground-based Cavorite installations could, in theory, be used as a form of weather control, as the Cavorite effectively creates a persistent point of low barometric pressure. All of this has a very relevant side-effect: Cavorite can be easily weaponized, but it is also controllable. Cavorite can only be manufactured through a specific process, and any country that wants to make large amounts of it would need to trade for some very specific machinery and materials. Due to this, we have a situation similar to Uranium, as another answer mentioned. While mass quantities of Cavorite could be used in things like weather control, or power generation or what have you, the consensus is that it's simply too unsafe. This could be explored in a Chernobyl-like accident where a Cavorite power plant's shielding failed, which effectively created a permanent hurricane around the region that made it impossible to re-shield. The storm may rage to this very day. For this reason, it is simply not allowed to have Cavorite present in large concentrations anywhere. While Cavorite could have many more uses if used in greater quantities, nobody's been foolhardy enough to try it yet; smaller quantities of Cavorite are only really useful in powering airships, so that's what the majority of it is used for. In actuality, the air that is shot out from the Earth's atmosphere would dissipate, and it almost certainly would not have enough speed to escape Earth's gravity altogether, meaning virtually all of the air that gets ejected from the atmosphere would fall back to Earth. But of course, dissipation theory is still in its infancy so it's still widely believed that the accident at the Cavorite power plant could eventually suck all of the air out of the Earth. [Answer] The material has negative mass, but its density is really low. Think of something like Styrofoam but, with negative weight. You still need a huge block of it to lift something, but you can still lift several times more than you can using hydrogen, helium, or hot air balloons. The very low density makes the material weak. Really the only thing you can do with it is make it into beads and put it in a large sack (like a giant anti-grav beanbag?). You can't build stable structures out of it because it breaks apart under stress. Also, needing a lot of material means that you can't do society altering things like build antigravity backpacks, or weightless horse carriages. [Answer] Possibly this resource works via refined resource repel unrefined resource with the unrefined resource being scattered throughout the ground. Resulting in floatation. But this means it cannot be used industrially as it does not lighten but repulse. But this could possibly lead to something like maglev trains with unrefined resource lining the rails & refined resource on the trains. Making airships not the primary means of transportation. [Answer] # Frame challenge The Graf Zeppelin had a lifting capacity of approximately 87 metric tons (192,000 pounds). It was powered by five Maybach engines, which provided a total power output of 2,500 horsepower, allowing the ship to reach a maximum speed of around 80 miles per hour (130 kilometers per hour) and maintain a cruising speed of 66 miles per hour (106 kilometers per hour). The power lifter of the United States Air Force in the other hand, A Galaxy C5 Strategic Airlifter, is able to lift approximately 270,000 pounds in comparison. If your world problem is that your ships don’t have a heavy lifting capacity, magical material is not the answer. Lifting gas is. The opening statement in this question is a head scratcher, because zeppelins had incredible lifting power. The shortfall if any is not really dramatic. We have [blimps today that airlift whole hospitals into remote regions](https://newatlas.com/skylifter-flying-saucer-airship/16611/#gallery:5), with a capacity of 150 metric tons. The very advantage an airship has over a heavier-than-air aircraft is nearly limitless scalability. An airplane can only be so large before it simply can’t land or take off. Your airships can be arbitrarily large and carry any arbitrary cargo as long as materials exist to hold it together. If your story requires moving really heavy items by air, some invented magical material is going to throw the story off. Readers will just be asking why you didn’t simply build a bigger ship. [Answer] What about something that harvests static electricity to use as mobilization power? The relatively large surface area of an archetypal dirigible and believable practicality of building the "balloon" part of the aircraft with, say, an electrically inductive metal skeleton, that could justify a whole slew of creative electromagnetic explanations for atmospheric buoyancy as well as propulsion. I would definitely look into a relatively inert balloon gas, though Helium is plenty believable and very stable, only reason we don't use it in "real life" is b/c it's harder (expensive) to come by. Elemental helium presents at typical terrestrial temperatures and pressures as a low-density gas, much lighter than air (which is essentially 80/20 nitrogen N2 and oxygen O2 gas), which is the reason for the season as far as the buoyancy. Problem is, Helium is SO buoyant in atmospheric air that it will often achieve escape velocity at some point and straight-up outpace of our orbit altogether. Since it is also non-reactive, it doesn't form mineral compounds that could potentially keep it trapped in crustal rock/sediment. To satisfy your stipulation of the minimal disruptive impact of this tech on other technologies and social institutions outside of air travel, this might be justified by the need for your static harvesting "vessel" to be in near-constant motion as well as navigable to areas of greater static electricity accumulation (dragging its metaphorical socks on the driest carpets of cloud that it can find.. wow feel free to use that tragically lame metaphor I just served everyone). Only airships satisfy the need for huge surface areas as well as mobility necessary to properly utilize this static harvester device. [Answer] You can lock it's negative-weight property to another conditions. * Temperature: You can make the material to require being heated at very high temperatures in order to reach a negative-weight of any significance (maybe the material normally weights -4g at 25°C but at 2000°C it weights -200Kg) * Electrical current: You can also make it require having an electric current being passed through. * Vibration: It can instead require it to be vibrated at certain frequency to achieve negative weight. Maybe you can also play with this and make it work at different frequencies depending on the type or shape of material and if you vibrate a certain type at the wrong frequency it won't be weightless. ]
[Question] [ I'm building a race of plant-like creatures that are pacifists in a pre-industrial age world. Because they live hidden in forests, caves, etc. and often blend in with the natural flora, occasionally one of them is killed either on purpose or by accident. I want to create an appropriate punishment for the aggressor that: * Doesn't kill or maim them * Is feared by outsiders * Instills a sense of respect for nature, perhaps encouraging vegetarianism/veganism in the perpetrator This is a punishment for outsiders, not their own kind. I've looked at [How can a pacifist country protect itself?](https://worldbuilding.stackexchange.com/questions/27582/how-can-a-pacifist-country-protect-itself) and will incorporate some of that to prevent the problem, but naturally people will ignore the defenses at some point. What kind of punishment would a tree inflict on a human who cut down their friend that doesn't entail death or dismemberment? [Answer] The punished becomes a tree. It is not punishment so much as sentence; a time away from his familiar world. The punished is not insensate during this time. He experiences the world as a tree - the light and dark, wind and sun, the comings and goings of the forest animals. Trees know suffering - insects chew his leaves, storms and ice crack his branches, he thirsts in summer heat. Trees know pleasure - of rain, of flowering, of putting forth root and setting seed. When his sentence is done the man returns to the world of men, changed by his time in the forest. The threat of being changed is terrifying because it is change, and the unknown. But sometimes, one who has been so punished returns to the forest later in his life, to ask that he again become a tree. [Answer] Fungal infection. These can be a real pain to shift even with modern medicine. Make the fungus show up on the skin of the offender as contrasting coloured or textured lines (so it could work regardless of original skin tone). The fungus needn't be dangerous as such or even particularly unpleasant, though it might itch a bit as it grows through the skin. Just something that people can recognise that can't be trivially removed. Up to you whether it might be permanent or not, or whether it could scar. It may or may not be contageous between humans, but they might believe that to be true and someone afflicted with the mark could be treated as a leper. Now part B, the fun bit. > > perhaps encouraging vegetarianism/veganism in the victim > > > Ever heard of an [alpha-gal allergy](https://en.wikipedia.org/wiki/Alpha-gal_allergy)? In the real world this is spread by tick bites, and causes an unpleasant allergic reaction to the consumption of red meat. You can certainly run with this idea, inducing a more general allergy to a wider variety of meat and fish or other animal proteins (eg. dairy). You could combine these two punishments together, with the fungus causing the allergy (and effectively making the allergy incurable) or separate them, with the meat allergy fading over time as a real-world alpha-gal allergy can do. That allows multiple options... temporary punishment, permanent punishment, and permanent punishment with effective branding. Merely possessing a meat allergy might be stigma enough, depending on the society the offender comes from. Depending on the sources of protein available, this could be anything from a mild irritation (if you've got good access to beans and oily seeds) to an extremely serious problem if you've got too few protein sources, or the ones you do have just don't provide quite all the nutrients you need. --- edit Now I think on it a little more, it is odd that intelligent plants would seek to punish animals by making them less inclined to hunt, kill and eat other animals. Seems like encouraging your enemies to hunt and kill your own pest species instead of eating fruits and grains might be far more useful and perhaps a little better suited to plant pacifism. The same suggestions I made above would work just fine, but turned around... induced nut allergies, gluten intolerance, etc. Encourage the victims to eat more deer, beavers, bunnies and so on. (see also: the [green pact bosmer](https://en.uesp.net/wiki/Lore:Bosmer#The_Green_Pact) of the elder scrolls series, a neat take on wood elves, who are carnivorous and cannibalistic) [Answer] Some pacifist communities, such as the Amish, punish criminals by shunning. No one in the community is allowed to speak to them or acknowledge them in any way until they have repented. In science-fantasy, I’ve read stories where a criminal is punished by being turned into what amounted to a living ghost, until they break down: no one could see or hear them. [Answer] Paralysis would teach a presumably motile predator or herbivore the sort of vulnerability an immobile plant experiences and instill a reliance on communication over wanton destruction to stay alive. [Answer] # Addiction Alcohol, caffeine, coke, opium and ayahuasca all come from plants. They are highly addictive. I may be wrong, but I believe coke and opium are the ones most likely to cause an addiction (specially if the victim has a troublesome life to start with). So refine that opium into heroin and/or the coke into crack. Tie the offender up for a week and feed them your extracts. Then release the bastard. You will see them come back for more on a regular basis on their own volition. Then you can impose conditions to give them the drugs. "Have you been sparing animal life and planting new trees lately?" And if they hurt themselves or overdose - you didn't maim or kill them, they did it themselves. Suggested theme song, if this ever becomes audiovisual: Sober, by Tool. [Answer] ## Restorative Justice The offender is forced to do community service for a period of time after conviction. Unless you have the cooperation of the offender's town's law enforcement, they'd have to stay. This serves multiple functions: * Separation from family/etc is a punishment in and of itself (that's a large function of prison). * The offender must work alongside the people s/he hurt, which leads to empathy and understanding. * The emotional pain of facing her/his evil deeds is also a punishment. * Outside labor is helpful for public works. This is especially true if the outsiders are bigger or stronger, but also true even if they are not. * The direct victims the offender injured, or the family of those s/he killed, get to choose if they will work with the offender or not. The offender has no say. [Restorative Justice](https://en.wikipedia.org/wiki/Restorative_justice) is a real concept that has worked in many situations. > > Restorative justice is an approach to justice in which the response to > a crime is to organize a meeting between the victim and the offender, > sometimes with representatives of the wider community. The goal is for > them to share their experience of what happened, to discuss who was > harmed by the crime and how, and to create a consensus for what the > offender can do to repair the harm from the offense. This may include > a payment of money given from the offender to the victim, apologies > and other amends, and other actions to compensate those affected and > to prevent the offender from causing future harm. > > > In this case I suggest a combination of Restorative Justice with relocation to the harmed community and community service/labor. For whatever period of time is appropriate to the crime and for rehabilitation. Potential offenders will fear it because it's basically prison and is a complete disruption of their lives. Add on that the emotional side of being confronted every day by those you harmed (if not the victims or their families, then their community) and having to work to help them. Anyone who has gone through this would return to their home completely changed, and possibly traumatized. It's much easier to do your time without any connection to your victims. [Answer] Extreme case of whatever poison ivy contains. Also, instead of just being contact-based, fine particles are released into the air (when the plant creatures are injured). Think about the chemical a skunk emits. The chemicals of poison ivy and skunk combined!!! In the case of a tree it's in its bark and on the leaves, and is released on the victim in case of attack. Unfortunately that only provides 1 & 2. I think veganism is going too far, but respect on the other hand - people respect skunks! You move to avoid a skunk at all costs. [Answer] # Brainwashing The plants use a chemical, neurosurgical, psychological or metaphysical method to remove any aggressive thought from the convict. The convict becomes docile and unable to even think of committing a violent act. The convict is also very likely to become a vegetarian, because they are now repulsed by the thought of causing harm to an animal. Outsiders would find the prospect of having their whole personality changed permanently into that of a "weak" pacifist to be quite terrifying. But the plants might believe that they are just helping them to live a better life free from anger and hatred. [Answer] We have many punishments that are not designed ot hurt the individual, but encourage better behaviour - one of these is the fine. If you commit an act that is not severe enough to warrant imprisonment (or some torture as practices in less civilised countries) then you'll be fined a penalty that should be sufficent to discourage you from doing it again. So your plant-based 'fairy folk' do the same - if you cut down a tree or squash one under your hobnail boots, that night they turn up to your house and quietly destroy the contents. You wake up and know you pissed the forest folk off. No doubt a suggestion that humans will respond with violence towards these creatures, but that often doesn't occur if the loss is only temporary like this (it'd be a different matter if they stole your children for example) - financial loss by someone is a given in human societies, and even though you'll be annoyed (and your neighbours possibly amused, or sympathetic) the response will always be to take more care in future, perhaps with offerings by the forest to placate them in case you offend them in the future. [Answer] In Star Trek's Vulcan society, a person who commits a crime, any crime, is isolated from society, to protect society from them, until they've reformed. Mind melds are used to ensure they've rehabilitated. So punishment is mainly the loss of freedom and privacy. (Source: the book "Spocks World" if I recall correctly.) Are your trees able to read the minds of humans? [Answer] Mind Control I don't know if you have magic in your world, or if you use telekinesis or other forms of mind control, but this solution should work either way. If you do, it's easy. The plant-creatures take control of the perpetrator's mind and (this probably isn't the right terminology) squeeze it, or call up bad memories, or force them to feel guilt and fear. It should be equally easy to force them to want to be vegetarian or vegan, although I don't know if the results would last forever. If you don't, it's a little trickier. However, there are countless psychological tricks to use. To name a few: * Tie them up, surround them with meat and leave them for several days. They'll be sick of the taste, the smell, even the sight of meat! * Use propaganda; have plant-creatures constantly talking to them, telling them how horrible it is to eat meat, and how wonderful it is to be vegan. If done for long enough, this could have lasting effects. * Make them feel guilty by showing the perpetrator the victim frequently, or if the victim was killed, parade the sorrowing relatives in front of him/her until they're properly remorseful. (This doesn't make them vegetarian, though.) * This one might be a little violent for pacifists, but they could use threats. Someone calmly detailing what 'will' or might happen to them, with a couple scary-looking people laying out potential instruments of torture while saying 'This is what happens to carnivores,' or whatever. Of course, they wouldn't actually torture them, but the effect would be nearly the same, and once the perpetrator was released and told everyone about what happened, the tale would probably spread and become worse with each telling. No one will want to mess with plant-creatures after that. ]
[Question] [ It’s common nowadays for many different types of fictional, and non-fictional, works to speculate on the possible existence, operation, and further expansion, of hidden organizations such as ‘deep states’, secret branches of known organizations, and so on. There are quite a few number of reasons why the leaders of such organizations would want to keep the secret show going but I am having trouble thinking what other reasons could motivate lower level personnel to do so, other than fear. The obvious rewards of exposure should more than outweigh any renumeration they could obtain. [Answer] The lower level folks think they are doing something else. Secret purposes. Grand schemes. Yes the Elon Musks of the organization can concern themselves with these sky high ambitions. Lower level folks are interested in payroll, expense accounts, personnel - the unsexy administrative work of making things go. Any large organization will have a cover purpose which ideally will not be a front - a hospital as cover will actually take care of sick people, a pizza place as a cover will serve pizzas an so on. The lower level people know that there are strategy meetings and doings they don't completely understand. They are uncurious, these middle managers. Their plates are full. [Answer] They just don't care, because their outlandish schemes are so weird that regular people will see those as crackpottery. Now a lot of what I am going to say next has to do with conspiracy theories and such. But let us consider, just for the sake of argument, that they would be true. Imagine that aliens have really been deactivating nukes. Or that the Earth really is flat. Or that chemtrails are actually real and you can protect yourself with a tinfoil hat. Keep adding in here whatever your favorite conspiracy theory is... From [AIDS being an artificial disease meant to eradicate black and hispanic people](https://en.wikipedia.org/wiki/Discredited_HIV/AIDS_origins_theories#Additional_theories) to [the notion that the day actually has 96 hours](https://timecube.2enp.com/). How does society nowadays treat the proponents of such "theories"? See where I'm going? Any member of a secret organization that tried to leak secrets out would be treated just like a mad person. They might be famous in the internet for a few days and become a source of memes, but that's as far as they go. Granted, some would-be detractors could be afraid to expose the conspiracy due to this. But many wouldn't be scared. They might actually make a living out of it, even get a cult following. You can make a lot of money selling books about conspiracy theories. You can also get rich on social media since YouTube still refuses to demonetize most conspiracionist material. It's just that this never actually harms the secret societies, so they just don't care. Like any major corporation nowadays, they see a high turnover at the lower levels of the company as a mere annoyance. [Answer] * Zealotry: the person really believes in the goals of the secret organization. * Belief in loyalty overrides desire to expose. * Mobility through promotion. Perhaps the low level thinks they will get to medium level and then high level. * Getting payoff in other ways like being part of a group or very individual reasons * Not wanting to rock the boat, its a paycheck type of attitude. [Answer] Keep them ignorant. The guy who makes payroll has no need to know what the job description really entails, and so on. Maintain a good cover story for their organization. Then, put about, at irregular intervals, conspiracy theories about what the organization does. These theories should be both internally inconsistent and obviously false based on their own knowledge. The guy who makes payroll knows that they are not paying their staff in gold. Have carefully primed agents who will draw attention to and ridicule the theories. [Answer] What you are looking for is a Great Unifying Truth, an element of knowledge which fundamentally changes the value and moral limits of everyone who learns that it is true. There are many great truths but the best example I can think of is "E.L.E." from the movie Deep Impact. In the beginning of that movie, there are two kinds of people: those who do not know about the impending extinction level event, and the members of an international conspiracy focused on saving a small fraction of humanity from annihilation. The members of that conspiracy do not keep silence out of fear. They are not extraordinarily well paid nor are their families being held hostage to assure their silence. They remain silent because each and every one of them, down to the stock boy who is organizing the canned food in the bunkers, knows that their silence is their only hope. The moment that the masses learn that an enormous meteor is approaching, their ability to save anyone drops dramatically. Every day that the secret remains, the bunkers improve and the supply stockpile grows. In such an environment, you could probably torture conspiracy members and they wouldn't let you in on what they know. [Answer] Once you're recruited, You're In Forever: * Committment: New members must commit a (often criminal) act that demonstrates their loyalty and/or an act that permanently marks them as a member. * Culpability: The secret organization knows something about you (like that act) that you don't want revealed. * Mystery: The full organization and it's powers are cloaked in secrecy but is regularly rumored and hinted to be much more expansive and powerful than most members ever see. * Culture: Rites and rituals and standards of behavior that reinforce the relative powerlessness of each member, demonstrate the benefits of loyalty, exercise the power of the organization, and openly (among members) punishes minor transgressions. * Observation: Minions are rumored to be frequently under observation and subject to occasional secret loyalty tests. Beware of minor transgressions or hesitations in loyalty! * Retribution: The secret organization will exact heinous revenge if you betray it. The organization has the (rumored) power to find and smash everyone and everything you value, and will never stop searching for them. There's no "reward" for exposure, only endless suffering for your loved ones. [Answer] Patriotism This touches on the explanation in some previous answers, but I think it deserves bold letters. The rank-and-file pawns of the conspiracy believe that they are serving the interest of their nation, as defined by legitimate government agencies. Whatever goes on in that forbidden floor is classified for national security reasons, and revealing it would not just cost them their job and their clearance, it would lead to the disapproval by upright citizens everywhere. They may or may not be able to get their book published. But afterwards? They can expect to be shunned by anybody except for a small group of fellow crackpots. This might even be possible if the pawns do not believe that they\re working directly* for the government. Mutter darkly about [critical infrastructure](https://en.wikipedia.org/wiki/Critical_infrastructure). "Let it slip" that middle management is preparing "disaster recovery plans." Hold security awareness lectures. If the front organization is new, talk about technical and organizational measures in accordance with the GDPR (or similar regulations elsewhere). Highlight that the front is going above and beyond in their compliance. [Answer] ## The rewards of exposure aren't all that rewarding I guess the primary "obvious rewards" would be book deals, television appearances and the like (unless I'm missing something more "obvious"), but to really capitalise on those you'd probably need to commit a lot of time to it (likely giving up your day job, which may even pay more), there isn't much of a guarantee that people will care much or believe you and people will lose interest soon enough (so it's only temporary profit). You also need to want that fame (or need the money), which could potentially be detected and avoided in any new members that are recruited to a reasonable degree. If you try to go the route of exposing their crimes to the government, the most you can probably hope for is not being charged yourself. Unless you want to opt for blackmail, but that's a whole other can of worms. Not to mention anything you yourself did for the organisation may affect your future career outside the organisation and/or your freedom. Then there's the question of how much information you actually have to expose. The top-level members will probably have some huge secrets, but what the low-level members know is probably a lot more limited, not that extreme and less believable if they're not a prominent figure in society (which would probably typically be the high-level members instead). Even if you just contrast this against the direct benefit of being a member, exposing them already doesn't make too much sense. Then add all the reasons mentioned in the other answers and it really doesn't make sense. The most compelling reward is likely morality and wanting people to know about it, but the organisation has already failed if you recruit people motivated strongly by this. [Answer] Speaking as a member of a formerly-secret conspiracy that remained secret for far longer than it had any right to, what seems to work best is loyalty. If your low-level members believe in the goals of the organization and have been personally recruited by higher-level members, they're going to do their best to keep things secret. (Seriously. It's virtually unheard-of for a group of 4000+ people to keep something secret for five years.) [Answer] The knowledge that they don't have enough to make anyone believe the organization exists. There have already been enough fake people come forward that any real whistle-blower will just get laughed at. [Answer] Ask what do they have to gain? If they are made to believe that they have a lot to gain they may easily conclude that what happens to someone else doesn't matter as long as it doesn't happen to them. No offense to any readers of German descent, but the German citizens had to know what was going on during the Nazi regime. And while many of them may not have agreed with what was going on, too few of them actually did anything about it. An overwhelming, armed "security" force is a good reason to look the other way, but throw in that it greatly benefits you (monetary gain, lifestyle improvement, etc.) has been enough to make lots of people throughout history do horrible things on a mass scale. Throw in a little racism and a pinch of brain washing (propaganda) for seasoning and you've really got something. Don't see why it wouldn't work in a corporate arena or secret organization. [Answer] > > You can catch more flies with honey than with vinegar. > > > <https://www.dictionary.com/browse/you-can-catch-more-flies-with-honey-than-with-vinegar> --- What sounds like a better recruiting tool: > > Hey, wanna sweep the floors at our headquarters where we're designing an orphan crushing machine? > > > or > > Hey, wanna sweep floors and get paid $1/hour more than average? > > > --- Even if some employees hear that you're designing an orphan crushing machine they would be hard-pressed to connect to the dots and verify such a claim. [Answer] This is sort of a low level answer, but belonging to something bigger than themselves motivates people to commit a great number of actions. Furthermore, belonging to some secret-society, even at the lowest level, makes you different from everyone who isn't. Essentially, a secret-society is tantamount to a cult. [Answer] Thinking of the past, think about slavery. There were networks of people in the north america running underground railroads. They kept it secret, because they believed the slavery was wrong and so they kept information about its location and its members secret so they could keep helping other escape. Sure the fear of getting caught, in the south, existed but the people doing it were motivated by helping people. I am not sure how big the organization was, but in the North they were free to operate with no legal consequences. --- Also if one county is being occupied by another, the native people would keep resistance movements a secret to try and free themselves. In the united states, 1700's, long before we declared war(war for independence) hundreds of people were enlisted. We had the minute men, and etc. Obviously any citizen who wanted freedom kept the information from the enemy. So freedom is a powerful motivator. ]
[Question] [ In a steampunk, class divided world, farmers are among the lowest people on the societal ladder. The establishment offer them very low wages for their labour and keep them where they are. Although they are oppressed, and there is danger to speak out against the government, many of this class genuinely believe that the establishment is good, and just in the way that it acts. Why would a member of this class disagree with someone who wants to overthrow the establishment? Why would he approve of, and even revere the oppressive establishment? A Why do they believe that the establishment is protecting them. [Answer] If the ruling class actually needs the approval of the lower classes, they are already in deep trouble. The romantic image of the lowest classes just organizing themselves and storming the palace of the evil emperor, followed by a happy end, only exists in fantasy and in political propaganda. The lower classes cannot do that even if they wanted to, as they lack the education, the means, the connections, and the skills for that. The state can easily stop any such attempt before it grows large enough. The police can easily arrest any troublemakers before they can achieve any results. Ohh, but it did happen in real history that the people revolted and changed the government, right? How did that happen? It happened because they were allowed to do so. The power of the ruling class is not based on the loyalty of the lowest classes. It is based on the loyalty of the class directly beneath the ruling class. The chiefs of the police forces to uphold the laws. Bureaucrats to collect the taxes. Military generals to protect from foreign threats. Banks, and the owners of lands and businesses to keep the economy up and running. Lose the loyalty of these people, and when a rival to your power appears, they will switch allegiance to him. And then they will allow the masses to revolt. There is a [wise saying](https://www.youtube.com/watch?v=rStL7niR7gs): it's not the people who replaced the king, the court replaced the king. Given this, it can still have advantages to have some loyalty of the lowest classes. Not because they would revolt on their own, just to make it harder for other powerful people who want to replace you, from being able to use them. Now let's look at the motivations of the lowest classes. Revolution is risky. You might get a better life, but you also might end up dead or in prison. So you have to weigh the risks and possible rewards. * Stability. There may have been revolts in the past, or in neighboring countries, and the people know it only resulted in chaos, and at the end, it didn't get better for the common people. A stable, powerful government is needed. Everyone knows that. There are external enemies who would conquer us if our nation gets weaker. Everyone knows that. We are important cogs in the big machine. It's the natural order of the things. Why would a different ruler be any better? - Yes, if a group which promises a utopia gets strong enough, they might instill doubts about the above values. But if [such](https://en.wikipedia.org/wiki/Marxism) [groups](https://en.wikipedia.org/wiki/Nazism) are allowed to grow strong enough, then you already have much bigger problems than the loyalty of the lowest classes. * Possibility of rewards within the system. If there is even the slightest possibility of improving your condition within the system, you might hope to be able to benefit from it, instead of trying to demolish it. A slave can be [manumitted](https://en.wikipedia.org/wiki/Manumission) for good behavior and faithful service. A simple peasant might earn the gratitude of the king by being at the right place at the right time and performing the right service. You might win the lottery. You might find some lost treasure. The probability of these things must be very low, to not upset the balance in the hierarchy too much, but if once in a while a very small number of lower class citizens are lucky enough to be able to climb one step of the social ladder upwards (and these events are given great publicity), it might instill hope in the others that they themselves might one day become lucky enough. [Answer] Look back at our history. A mix of tradition and indoctrination can make people accept their condition, for the major good of the society/deity. Add to this strong punishments for those who attempt rebellion, and some poor old folk may prefer the usual, poor life to something even worse. [Answer] In 1984 by George Orwell the lower class all 'approve' of the government. I think the book does a good job explaining how come. In short: * they fear the enemy, other countries * they fear the repercussions they face were they not to approve of their own government * they've been indoctrinated throughout their entire lives A good real life example of this is North Korea where the state does exactly this. By constantly bombarding its citizens with propagenda (in all forms, from television to school classes) and sending rebellious citizens to camps. [Answer] Fear - people who disagree with a powerful ruling class may end up losing what little they already have - maybe even their lives. Social inertia - It was good enough for my parents and their parents before them. Why should we try to change things? It's the natural order. Brainwashing - Our teachers and our great leader says it is so, therefore it must be so. A talent for exploiting the system - Such people always exist. They use their wits to make deals and gather resources for themselves. Very often bribery, corruption and currying favour are involved. They are doing well and have no need to upset the apple cart. [Answer] # They are too hungry to worry about it There is a term for farmers that live off what they produce, "subsistence farming". That is, if they don't have a good crop, they starve. If you have to sweat every day to feed yourself and your family, to provide clothes and shelter, why would you have time to worry about your oppressors? Add a village priest announcing that "the meek will inherit the Earth," and you don't have much to worry about at all. # Edit Note to haters: The OP never specifies that the prevailing conditions in society were anything like Victorian England. A steampunk US where the South won the Civil War could have slaves. Stop telling me what Victorian England was like, that has nothing to do with the question or answer. [Answer] All of the existing answers are quite similar to one another, so I'll change it up a bit. Since you're building a world, and you haven't given us the full parameters of your world, somewhere in the part we don't know there may be a reason why it actually is just for your social order to exist the way it does. If the Aztec priestly class had been correct that the sun wouldn't rise in the morning without blood sacrifices...blood sacrifices would have been just. If witches actually did exist and a population of innocents was in danger of being tempted into eternal damnation at their hands, the medieval burning of witches would have been just. Etc. Basically any situation where the story told about the world by the ruling elite is true would make support for the institutions of the elite rational and just. If your steampunk world became a steampunk world because the elite possess some ability that the farmers do not, and that ability has resulted in rapid technological advances that our world did not experience - then it's not irrational for the farmers to want to leave the rulers alone, so that they can continue to propagate those advances. [Answer] Fear is a powerful motivator, but not just fear of government reprisal. Some people will be afraid that even if they win their rebellion, the changes put in place by the new government will be just as bad or even worse. Look at how so many regime changes in real life have turned out; a few good examples include the French Revolution, Rhodesia/Zimbabwe, and the Haitian Revolution. In all of these cases, the revolutionaries got their way and things only got worse. [Answer] Religion is always a great reason. You are the lowest rung of society because of transgressions in a previous life. If you follow the laws of those above you and stick to your caste, you will be moved up a class in the next life. Eventually you'll be ruling class and from there eternal reward. Religion is great because you don't have to prove anything. People just believe it. [Answer] All you need is a scapegoat, and almost any will do. This answer will get politically charged if I lean on any present-day real-world examples. But pick any time or place in real human history (or present, but maybe lets shy away from that for now) and observe racism, zealotry, or just any form of tribalism altogether serve as the basis for an invented or exaggerated enemy. The systems at play can be varied: genetic, religious or moral, economic, philosophical (i.e. political models), or even geographic. The common factor is how easily people in power can sell a message rooted in any form of tribalism, redirecting the majority of fear and consequent hatred to some external force. Even better, the oppressed will then place their faith in their real oppressors to protect them against such external threats whether completely fabricated or just exaggerated, and gladly surrender the power needed for that protection. This answer is light on details, but mainly because you can pick almost any. A known oppressor has the benefit of familiarity and the effects of [Stockholm Syndrome](https://en.wikipedia.org/wiki/Stockholm_syndrome), while outsiders are automatically subject to rampant xenophobia. And if some real external threat need no exaggeration, that's even better, for such are the times when super powers are born to long outlive the conditions that birthed them. [Answer] Consider any of the following Real life examples: i) The churches regime ( maybe not what your looking for considering you did't mention a belief system) ii) The monarchy in Britain, even today many working class people love the royal family. The queen acts a surrogate mother figure that the nation can unite behind. iii) American capitalism despite the fact that many Americans are below the poverty line they are adverse to changes in policy that would improve these conditions seeing the nordic socialist model as too communistic. iv) The caste system in india which despite the cultural influences now reaching the country many people refuse to abandon ( infact particularly in the poorer areas it has stuck around) v) China , currently very oppressive their leader has even written into the constitution that he cannot be deposed. Yet the chinese are in general still very proud of their country. Their willingness to accept such a state likely deriving from their ancient idea that a kind is divinely chosen ( although they also believed that if he lost favour with the people he had been deselected by the gods) I'm sure there are many more than what I've mentioned here but it should be enough to get you started [Answer] If your society's farmers are at the bottom of society, most likely they literally "live off the land". They don't buy the essentials for survival, they grow and breed them. That was not so far from the truth in the UK within the memory of a few old people who are still alive. My grandparents lived in the time when farm workers were literally paid wages once per year - they didn't have any need to use money on a regular basis to survive. And the same farmers know very well what happens if you stop farm work for a few months. Over a one-year timescale, you starve. But so long as you are used to hard work 365 days a year, actually it's a pretty good life. The best part about it is that you don't have to worry about anything much that is "above your pay grade". So why would you want to disrupt the status quo? You can be pretty sure that you won't get any benefit from doing that. One premise in the OP's question is wrong, though: they don't "genuinely believe that the establishment is good, and just in the way that it acts." They don't believe it is "bad and unjust" either. Like the weather and the yearly changing seasons, the establishment just is. It's not something to spend time thinking or worrying about! [Answer] A followup to this part of L. Dutch's answer: > > some poor old folk may prefer the usual, poor life to something even worse. > > > The Devil you know is usually better than the Devil you don't know. Tie this to your country being the head of an empire, memories of Rebellion Gone Horribly Wrong (i.e. The Terror during the French Revolution), and not being too oppressed (rulers learning the right lesson from the Revolutions of 1848), and you've got a relatively stable class-conscious society. [Answer] This is actually pretty much the standard condition world-wide. In many countries, such as the USA, there is a political alliance between the ultra-wealthy and the dependent poor, together pitted against the middle classes. Typically the rich and the poor agree on a few things: ever-increasing taxes levied against the working and middle classes (which include small business owners), the money going to pay for ever-growing government bureaucracies and government-connected institutions like banks (making the ultra-rich richer and more important), bureaucracies which give handouts to the dependent lower classes who are, if not grateful, at least psychologically addicted and willing to viciously fight to keep those handouts. Both groups will furiously attack and demonize the working and middle classes when they ask for things like tax cuts. [Answer] Poorly educated, non-integrated, hungry, hand-to-mouth poor peasants are supremely susceptible to propaganda. They don't know any better, or have bigger concerns than who thinks they can wear some fancy hat. The powers that be need only provide a life slightly better than what the peasants think they would have without it. We are protecting you with our flashy weapons, from those that would kill you, or take all of your food. We care (tm). Or they need to control the local authority. By the way, head man, here is some cream for you skin, that's much better yes? I'll try and get some more next month, but its not cheap. It would really help me convince them if you filled this truck up full next month. Also here is the salt you really need. And wow you are lucky to have such a daughter. Lets keep it that way. Or reward those who take on the dangerous labour (and they will because they are starving). I'll need twenty volunteers to help us dig this yellow stuff out of the ground. Those that do will get food drops for their family. Any individual that rejects such a system is either rich enough to dislike it. Such as the local authorities children who are probably better off, and feeling indignant. They may have been educated somehow, say by a traveling merchant that has brought to light contradictory news, or by some omission from a loose tongued guard. Alternately the system failed them, and now feel that not being a part of it is in their better interests. The rest won't follow and will actively support the system. [Answer] Because they [the oppressors] could be worse, especially pertinent if the oppressors before the current ruling faction were worse, or if the current rulers were much worse and have mellowed due to reforms. If overthrowing the group that is currently top of the pile is seen to include the possibility of a return to the bad old days then the current regime is preferable even if they aren't as good an option as you might like. [Answer] The oppressors tell the oppressed that some day they'll earn their way to the top, and that if you haven't yet you're just not trying hard enough. Plenty of people will see through it but plenty won't. Thanks to this beautiful little thing called the sunk cost fallacy most people who blew everything on what they thought was their ticket to success will rather hang on to their false hope than reject it, and so long as the lower class is inundated with stories of how the richest man in the world was once a lowly farmer that hope will have no trouble getting started. Combine that with a few shows of force every now and then, attacks from outside for the elites to protect them from, and artificially cultivated animosity between subgroups of the common folk, and those few who don't see their oppressors in a positive light will still be discouraged from speaking out against them. [Answer] Probably hope. Make them think that they could get into the upper class; take your inspiration from today's world ! Accordingly, tell them that your current upper class of course deserves it all and that you can also make it if you just worked as hard as they did. [Answer] These things actually happen in the real world, there are many examples and many reasons. Religion might be used to keep people at bay. People might just simply not know any better. If that is the system they had always known, and possibly in the past or somewhere else it is/was even worse, they'll be ok with it. If in the past people were also enslaved or beaten up, it won't seem too bad to simply have to work for a poor pay. Brainwashing: you can make people believe it is good. And make them believe that outside, in all other places, it is worse. Whether that it is true or not. You can find examples of this literally everywhere around the world. In some countries there are codified classes, and people keep accepting it, for religious/cultural reasons. In some countries there are monarchies, and people seem ok with being inferior to the royals. In most religions women are considered inferior. Even just in the Catholic Church. Yet churches keep on being full of women, who seem ok with the idea. If you internalise some concepts since you're a kid, you won't question them too much. In USA, most people would benefit from public health system and public education. Yet among the poorest classes you'll find millions who defend a system that goes completely in their disadvantage, just because that is what they have been taught to believe. In most Western countries people who can barely make ends meet will pay money to go to see the new illiterate reality-show star showing up in a club for half an hour. Is that different from accepting that you are underpaid, while some other people just deserve more, and even being happy about it? You really do not have to invent too much to create a reality where the lowest classes will happily defend the oppressing system. [Answer] While the question makes clear we are talking about revering the current government, it's worth pointing out that you can have people supporting something they detest if they see the alternative as worse Real world examples include Churchill allying with Stalinist Russia in WW2. [Answer] in general human beings are afraid of change. a sudden change to the entire ruling system could have disastrous effects on society and the economy on which these farmers rely. they may not live in the best conditions but they can still get by. the government would need vital industries such as farming as well for food production as well and would protect farms and such from any sort of crime offering the low class farmers a much safer life than other low class civilians [Answer] The [Caste System](https://en.wikipedia.org/wiki/Caste) Everyone believes that they are where they are in life because they deserve their circumstances. The poor believe they are poor because they deserve to be poor. Possible because of their own actions, religion, genes, or any systematic reason that you come up with. They also believe that their rulers and oppressors are where they are because they also they deserve to be there. It is their right (again because of religion, morality, hardwork, whatever). So everyone feels like there is a grand sense of justice in the system, even if things are chaotic and unjust on the surface. So this sense of justice should stop the general population from wanting to overthrow their system because it would be immoral, and wrong. Maybe they believe that if they do the right thing they too will succeed. The point however is that the people keep themselves down, rather than the government having to do anything. [Answer] It is easy to know that the nobles as our betters. They are taller, stronger, handsomer, better educated and possess a refined speech and manner that we could never match. Raised from the cradle to be confident and self assured they are brave, honourable and skilled in equal measure, the very definition of natural born leaders! Magnificent in their benevolence and terrible in their wrath they are everything a man could aspire to be and more. Surely the favoured of the Gods, it is only natural that we should defer to them. [Answer] For an in depth look at a revolutionary movement in a Steampunk world, I recommend Charles Stross' Merchant Princes series. New Britain is a steampunk, class divided world introduced in the second book in the series, The Hidden Family. It has an authoritarian system and the reader meets a revolutionary network seeking to overthrow the status quo. The network features prominently in subsequent books. [Answer] Historically speaking, a static Status Quo dissuades rebellion, as does a steadily improving quality of life. Almost every uprising of lower classes has coincided with a sudden drop in quality of life. In short, if the oppressors are reliable and those oppressed don't know any better life, they don't rebel. ]
[Question] [ Closed. This question needs to be more [focused](/help/closed-questions). It is not currently accepting answers. --- Want to improve this question? Update the question so it focuses on one problem only by [editing this post](/posts/55665/edit). Closed 7 years ago. [Improve this question](/posts/55665/edit) Assuming standard medieval "firstborn son or next closest male relative" inheritance. A King (A) dies without heir. His Brother (B) inherits the throne. 8 months later the dead King's (A's) wife gives birth to a Son (C), conceived by the dead King (A) before he died. Who is now the rightful King? C is the firstborn son of the rightful King, so there's a strong case it should be him. But B has been crowned King before anyone knew C would come along. Obviously either way the throne will be very unstable (which is my intention) but who is the "rightful" King? [Answer] ## Chances are good you have a civil war, a BIG one Look at Japan for my reasoning, specifically [the Ōnin War](https://en.wikipedia.org/wiki/%C5%8Cnin_War). Long story short, the emperor doesn't have a kid, so he asks his brother if he wants to be emperor when he steps down. His brother says yes, but then the king has a kid, now it's time to play who's going to be the next [shogun](https://en.wikipedia.org/wiki/Shogun) (which is basically an emperor), vote on your iPhone 7 now. Everyone voted so hard that the palace burned down and the empire shattered into dozens of smaller clan based territories. In the British royal family, another uncle/nephew situation happens. When Edward IV died in April of 1483, he passed the crown off to his son, who was only twelve. Because his son was 12, he had his brother, Richard III, to take super good care of him until he was old enough to rule. Richard III was a super cool uncle who had fun times with his favorite nephew for about three months until Edward's son promptly disappeared, leaving grieving uncle Richard the king. So at the very least the child will disappear and at the worst, your country will shatter. --- As to who is the rightful king is, it depends on your rules of succession. If they follow English rules, it is the uncle, he has already been coronated. If you follow the Japanese rules, it is who ever the old king picks before he dies. [Answer] The question of who is the "rightful" king depends entirely on the political doctrine of the country in which it happens. I mean think about it this way: if JFK's wife had a baby six months after he was assassinated, would the baby become President? Obviously not, because American political doctrine explicitly accounts for who becomes President if the current President dies in office. That being said, it sounds like we're talking about a stereotypical European monarchy, probably post-Magna Carta. In that case you're talking succession via [primogeniture](https://en.wikipedia.org/wiki/Primogeniture). Do we have any examples of a similar situation happening in a European monarchy? Well, history is rich and varied, so indeed we do! Turns out that in France in 1316, [something similar happened.](https://en.wikipedia.org/wiki/Salic_law#The_succession_in_1316) Old [King Louis the Quarreler](https://en.wikipedia.org/wiki/Louis_X_of_France) was on his deathbed, but his wife was pregnant. He made some contigency plans, which involved his brother being regent for the baby, should it turn out to be a boy. The king passed, the regent took over, in a few months the baby was born [and died five days later](https://en.wikipedia.org/wiki/John_I_of_France), and the regent [didn't have to move out of his comfy chair.](https://en.wikipedia.org/wiki/Philip_V_of_France) Now, this was slightly different than your case - the old King had made arrangements for his brother to take over the regency. In your hypothetical situation, it sounds like the old King either didn't know about the pregnancy, or was somehow unable to make arrangements for it. These things depend on the actual laws of your kingdom, and more specifically they depend on the concrete wording of the laws. Further, and this might be something they've worked out for other forms of inheritance, it also depends on whether or not your country considers the infant a person at the time of the king's death. In that case there's three different scenarios: If the law is written such that the crown transfers immediately upon the death of the previous King, and at that point it transfers to the next heir as defined by primogeniture, and the law does not consider a baby in the womb to be a person for the purposes of inheritance, then the "true king" is the brother B. On the other hand, if the law considers the baby in the womb to be a person for the purposes of inheritance, then the "true king" is the child (even if he is otherwise indisposed at the beginning of his reign, what with the gestating and all). If he turns out to be a she, then whoops! She wasn't ever King, it was the brother B all along. On the third hand, if the law is written such that the crown always belongs to the heir of the previous King (which is easy to do with sloppy writing), and the law does not consider a baby in the womb to be a person, then the "true king" is B until the baby is born, at which point the crown transfers to the baby. So at this point, the question becomes: what are the laws and political doctrines of your country? That'll tell you who the legally-determined "true king" is. If you have some sort of magic that rides on the legal definition of the true king, this might even matter. But like all the other answers have said, the real mark of a king is keeping your butt on the throne. Whoever manages to do that, by hook or by crook, is the "true" king. [Answer] Standard [primogeniture](https://en.wikipedia.org/wiki/Primogeniture) means first born inherits. Anyone who isn't born yet when someone dies can not inherit. When the king dies, the brother B inherits and the throne continues with his bloodline. Traditionally, kings stay king until they die or abdicate, so when the kid C is born, B stays king and will inherit the crown to his children. However, inheritance conflicts are traditionally solved through bigger army diplomacy. So when there is a large amount of wealthy people who would for some reason consider B a bad king and would rather be ruled by C (which would mean regency by the mother of C until C is old enough), then there is a chance they might hire some soldiers and start a succession war. [Answer] My answer's not all that different than some of the others, except that I'll add War of the Roses... Rules can be different, but standard is: born before the king dies in the succession line. Basically, I am joining chorus of the other answers...Under the standard rules, unless the kid is born prior to the King's death, the King's brother does inherit. However, this child is the perfect vehicle for anyone not satisfied with the way the brother does things. Succession would pass the King's son right up and there would be a bit a of a scramble to decide exactly what position the son would hold. Now, if the King knew about the pregnancy prior, and wrote up some successionlaws, then, yeah, baby can inherit with a regent. Of course it will be unstable--oh and, going to say, do look into the War of the Roses. There were all kinds of fake princes, many of whom only bore a passing resemblance to the people they were supposed to be. It was pretty epic. And they actually kept two of the fakes in noble households after they were revealed, just so they could trot them out when another fake came round or if rumors started that a former fake was actually real. [Answer] When a king dies or is recently crowned, the standard rule applies: You can argue to have a strong claim if you have some claim and powerful backers, or are yourself powerful. The weaker the actual claim, the stronger your backers need to be. If you win the resulting power play, history will write down that you did indeed have a strong claim. If you lose the resulting power play, history will write down that you did not have a strong claim. If there was some kind of settlement with members of both parties surviving, it could go either way. Inversely, if you have what seems to be a strong claim on paper (based on historical precedent), and someone else also has a claim yet is more powerful, history will either write down that you did not have a strong claim, or it will simply mention that you died under mysterious circumstances. [Answer] The answers are all well and good, but miss a key point that is largely ignored. A child is not considered the child of a man, even when it is 100% certain the child is theirs, until the child is officially recognized by the man. That means that the child has no official claim on the throne even if the relationship is known 100%, because the child is not recognized as a possible heir to the throne. Sometimes the rules are different, but not often. This also means that a heir doesn't have to be the genetic offspring of the king to be the heir in many cases, because a man can recognize whoever they want as their child. The reason that non-recognized offspring can make claims is due to royal blood is considered holy and are rightful rulers, therefor, if you can link yourself by blood, even if your line isn't recognized "officially", those claims in that thinking is valid. The most likely thing to happen though, if the brother/regent/king doesn't want a possible future war is to marry his daughter to the kid and raise him as his own kid. This way it ensures his line, and prevents factionalization, unless he already has a son and then it probably wouldn't be a bad idea to marry him off to a foreign powerful land who needs a male ruler. [Answer] Depends. is it a nordic country? if so, nordic contries were ruled by what we call agnatic (male-only) seniority ( the oldest son or the oldest capable living relative) or regented seniority ( the oldest capable family members rules until the oldest capable son is mature), and the brother has a strong claim on it. is it a anglo-saxon or frankish country? if so, we're in a agnatic regented primogeniture, the first son of the deceased king is the only rightful ruler, though his reign may be in the hands of a capable relative elected by a noble council. is it a old norse / iron isles (ASOIAF) kingdom? if so, a council of nobles will pick the next successor from a group of candidates. is it a dornish (ASOIAF) / 7-8th century spanish muslim -like country? if so, it's an agnatic-cognatic primogeniture with no stablished regency, you might end up with a 1yo king (or queen) ruled by his council. [Answer] Looking beyond Europe, the closest facimile of your situation in Persia in 309. Hormzid II died in 309 AD. He had three sons and his wife was pregnant with what turned out to be the fourth. His son Narseh took the throne for a couple of months and was generally reputed to be a tyrant. 14 days after the child was born (a son!) the grandees assassinated Narseh, blinded the second oldest son, exiled the third oldest son out, and crowned the youngest child king as Shapur II. (My source is this excellent [book](https://books.google.dk/books?id=LU0BAwAAQBAJ), summary at [wikipedia](https://en.wikipedia.org/wiki/Shapur_II)). Good thing they got a son I suppose. As for what happened to the kingdom....it worked out great. You can read about Shapur II on wikipedia under the title "[First Golden Era](https://en.wikipedia.org/wiki/Sasanian_Empire#First_Golden_Era_.28309.E2.80.93379.29)," which tells you about all you need to know. Shapur reigned for 70 years of stability, expanded Persian rule in Arabia, killed Roman Emperor Julian the Apostate in battle (the last pagan Emperor, fyi), forced Rome to cede Armenia and Georgia to Persia as client states, etc. [Answer] I would imagine the most likely scenario would be that as soon as the pregnancy is verified, the new king (ie the brother) would do everything he possibly could to arrange a termination. Whether that just means forcing an abortion or actually killing the former queen would depend on how well disposed he was to her, but assuming he actually wants to keep the throne, this baby is such a major threat that he realistically can't do anything else. If he doesn't kill the baby (preferably before it is born) then he risks his country going down in the flames of a civil war. He hasn't been on the throne long enough to have a strong enough support base to be able to let the child live. His only other realistic option is to step aside from the throne (and possibly offer to act as regent until the child is of age). However, given that he's already been legally crowned king this would mean formally abdicating, which could have implications for any future claims to the throne either by himself or his heir's. He needs to be careful here because he would still legitimately be the next in line after this new baby; he doesn't want to throw that away because what if this child were to die before having children of his own? A formal abdication could take him off the list of succession permanently. From the queen's perspective, as soon as she realises that she's pregnant she's going to realise the implications to her own safety. She'll need to quickly work out which of her friends are actually loyal to her. She's also going to need to make news of the pregnancy public knowledge as quickly as possible; if everyone in the country knows about it, it will make it much harder for the new king to act against her. That said, depending on his character he may try to do so anyway. There's even a risk that someone else may try to kill the child without the king's approval, on the grounds of supporting the king or avoiding a war. Finally, there is one potential way out of the predicament for all parties. The king could raise the question of legitimacy. If the pregnancy and birth were concealed for even a couple of weeks, it would be very easy to argue that the baby was actually conceived by someone other than the former king; ie it would be put to the public that after the king's death, the queen had sought solace in the arms of another. Thus the child has no claim to the throne. The queen would need to be part of this for it to work, so she would need to knowingly allow the child to lose his rightful throne in exchange for allowing him to live and/or avoid a civil war. Perhaps he'll be given a consolatory Dukedom as some kind of compensation (the queen would have be in a very strong position at the negotiation table on this). It would even be possible for the concocted story to be that the father was actually the new king... which would be a way for them to "do the right thing" for the child (ie give him his rights, eventually). But this is unlikely as the new king would need to be complicit in the story, and it really wouldn't sound good for him to have been doing that to his brother's wife right after he died. Plus it would have implications for the line of succession of the new king's actual children. [Answer] If the old king (A) explicitly stated that his brother (B) should succeed then this would overrule the claim of (C). Even if he didn't the brother (B) would still legally be king because the brother was king before the child was born. When the child was born he would be born as a prince of the blood, not a royal prince. This means his place in the line of succession would come after the brother's (B) children. [Answer] I think current laws are rightful. If man die he's posessions are inherited by his parents (but our A likely lost his parents some time ago) wife and children. If new child was born after his father die and if there's no doubt about A was his father - the posessions are redistributed to take some part to new child. So if there is no doubt about C is first son of A (for example if A's widow relocated to convent after A dies), C becames true king, and B can be a true regent while C is younger than age of majority. And of cource B could kill infant C if he want to stay a legit king. ]
[Question] [ Alternate dimensions/timelines are an important part of one of my settings, a modern fantasy. Magic is well known, and it is possible for objects to be enchanted by a powerful magic user to connect to other universes. Traditionally mirrors are used for this. Each mirror can only be connected to a single alternate universe. These mirrors are very rare and expensive, but luckily one of my main characters happens to own one that he got as a gift. A major plot point is that while the characters in the main universe, Universe A, can freely go to the other universe, characters in Universe B cannot cross over to Universe A. I have two ideas for the reason: * It’s illegal in Universe A to bring natives from alternate universes there. * It’s literally impossible, due to a magical lock keeping people from Universe B from crossing over. Whatever the reason, this restriction would need to be removed at some point so the plot could progress. Any ideas? Other Details: * Universe A is urban, very similar to our world, albeit with several nonhuman sentient species and magic. * Universe B is a somewhat dystopian version of Universe A, humans live in walled city states, and the other races are forced to live in disorganized settlements * All my main characterss are not human, so the Universe B main characters live outside these city states. [Answer] Universe B does not (yet) have magic mirrors. Universe A magic mirrors do not connect with a corresponding Universe B magic mirror. Sort of like In Mary Poppins, Bert's sidewalk chalk painting does not connect with a sidewalk chalk painting at the destination - Bert, Mary and the kids enter the chalk painting and emerge in the countryside of the alternate dimension. The cartoon residents of that dimension cannot come into our dimension the same way. Your mirrors connect similarly - some way such that people come thru and go back the way they came, but not vice versa. B people cannot use this route to leave B. In Mary Poppins they were pulled back to their own world when the chalk painting was destroyed by rain. Maybe something has to happen to the mirror in A to pull the travelers back through - like the lights go out. It would be a good story way to ensure you were not trapped - your magic mirror is set in the garden, and you have until sundown. Unless there are artificial lights... - Later in your story the Universe B people, realizing that magic mirrors are possible, eventually make their own. They too are one way and they are more Universe B; different, possibly sinister. [Answer] Because everyone knows they would die In Universe A these mirrors are well known and studied by some very smart people. Even though the average Joe cannot easily obtain a mirror, it is well known to the average UA resident that if you try to bring anything living from Universe B back into UA it will die. Everyone knows this in UA, it's a simple fact that everyone has heard. I mean have you ever met anyone on the street not from this universe? If anyone from UB asks to come with the characters back to UB, the character from UA will have to tell them that unfortunately it just is isn't possible. As everyone in UA knows, a UB'er will not survive the trip into UA. You can even add horrible details of how painful they heard the death was. But.... Through a series of events someone from UB either decides to risk it, accidentally falls into the mirror, or is faced with a dire situation anyways, so hey why not. Much to their surprise they open their eyes to UA, and conveniently for them they are still breathing. Turns out those smart people had a reason to misinform people, and due to the rarity of the mirrors, and the high cost of proving them wrong those smart people were successful. [Answer] The level of ambient magic in Universe B could simply not be high enough for its natives to pass through a portal. Natives of Universe A are not creating a connection when traveling back to Universe A, but are just dropping their current connection. Perhaps the existance of the portals is actually bleeding magic from Universe A into Universe B, and eventually, the ambient magic of Universe B will rise high enough to allow B-to-A travel. [Answer] Disease. Before travelling from Universe A to Universe B, you have to get a set of vaccines to prevent you from contracting common Universe B illnesses. If you do show signs of contagion, there are procedures in place for returning to the Universe A medical center and getting treatment in quarantine. All Universe A citizens are well informed that allowing a Universe B resident to travel into Universe A has the potential to trigger a plague that could kill off millions of people. Later, you could have someone "find a cure" for the disease (or determine Universe A residents couldn't contract it in the first place), retracting the travel ban. Or you could determine that it's only actually contagious if you show certain signs within the last three weeks, or a Universe B resident stole a mirror and released the plague already, sending all Universe A citizens running to the doctor for a vaccine they wouldn't normally bother to get. At this point, why bother closing the barn door after the cows have gotten out? [Answer] # Mirrors are linked to their travelers Any one can safely travel through a Mirror from World A (I'll refer to all worlds merely by letter from now on) to B, and thence, back through that mirror return to A. However, Travelling through a Mirror from B will send the traveler to C. Unfortunately C is desolate, inhospitable and unpopulated. Normally anyone who travels there perishes since there are no mirrors to return to B through. Since no one ever comes back from B everyone just assumes it's lethal to travel by mirror originating from B. Eventually someone does bring a mirror through from B to C after which it's discovered that mirror travel from C to A is possible, and travelers from B can return from C to B through the one mirror that was brought there. [Answer] Universe B is quite literally the opposite version of Universe A. So much so, that everything in *Universe B is in fact made of antimatter. Antimatter is perfectly harmless with itself and behaves exactly like ordinary matter (other than the fact that they have positrons and antiprotons instead of electrons and protons). However, we all know that matter and antimatter don't mix: when such particles interact, they violently transform into pure energy. So how can people from Universe A use the mirrors to explore Universe B? Well, the mirrors are more than mere portals between universes. A better analogy would be an airlock. Crossing the mirror from A to B applies a magical "antimatter shielding" to each individual particle, such that they behave exactly like antimatter particles. When returning to Universe A, the shielding is stripped away and the ordinary matter behaves ordinarily once again. Unfortunately, the mirrors were developed with this explicit "A $\rightarrow$ B = wax on", "B $\rightarrow$ A = wax off" rule. Therefore, if anyone or anything from Universe B tries to cross into Universe A, the mirror won't be able to place "matter shielding" on them... to horrendous effect. Now, you can choose how secure the mirrors are regarding Universe B objects. They can be dangerously unsecure, such that objects and people CAN cross, but there are just rules forbidding it for the simple reason that if anything were to cross, it'd be the equivalent of multiple nuclear bombs the moment they crossed.1 This would be the equivalent of the mirror going "oh, this object has no shielding to wax off, so ignore it". * They can be secure, forbidding non-shielded (anti)matter from crossing back into Universe A. You can also choose how severe this security feature is: + It may be harmless to those attempting to cross: the mirror momentarily shuts down as soon as the first non-shielded molecule attempts to cross1 + It may be harmful: the mirror allows the molecules to enter,2 but upon detecting that they are unshielded, destroys them. So if someone from Universe B puts their hand through the mirror, they'll no longer have a hand. + It may be lethal: the mirror allows entire objects/people3 to enter before determining whether they are unshielded. If so, the entire object/person is destroyed. --- Later on, this problem is somehow overcome, such that people from Universe B can cross over to Universe A. As others have suggested, this may be by people from Universe B developing their own mirrors. This would imply that members of each universe must use different mirrors. Another option is that someone figures out how to "hack" the original mirrors to allow passage. You can once again decide how easy or hard this is: * They just had to change the mirror's behavior from "A $\rightarrow$ B = wax on", "B $\rightarrow$ A = wax off" to "unshielded = wax on", "shielded = wax off". This implies that the antimatter shielding for ordinary matter can be trivially repurposed as ordinary-matter shielding for antimatter. * They had to develop shielding suitable to make antimatter behave like ordinary matter, and then make the mirror's "code" more complex: "if A-matter, A $\rightarrow$ B = wax on antimatter shielding, B $\rightarrow$ A = wax off antimatter shielding; if B-matter, B $\rightarrow$ A = wax on ordinary matter shielding, A $\rightarrow$ B = wax off ordinary matter shielding". --- 1 (yes, this footnote appears twice above) Some magic handwaving will be needed to explain why random air molecules from Universe B aren't a problem (either generating massive heat on the Universe A side or causing the mirror to constantly shut down). Or just ignore this point. 2 Note the word here is "enter", not "cross". This implies that the mirror isn't a door, but a bridge between the two dimensions, such that objects actually don't go A $\rightarrow$ B (or vice versa), but A $\rightarrow$ mirror bridge $\rightarrow$ B. The travel between both ends can be virtually instantaneous as far as anyone is concerned, but this bridge is the "safe zone" where the unauthorized unshielded antimatter can be safely destroyed before it can enter Universe A. 3 Some more magic handwaving (or authorial ignoring) will be needed to explain how the mirror identifies what constitutes an "entire object/person". [Answer] # Universe A is 'higher' on the planar scale than Universe B This means that, just like falling vs climbing, one-way travel is easier. ## But things are attracted to their plane! Meaning that, a person going from A to B creates an effect like a rubber band being stretched. So, when they want to return, this rubber band is enough to overcome the difference in 'height'. ### So how is this resolved? One of 3 ways: * The rubberband effect allows stowaways. Someone realizes that passing a sufficiently heavy object (either literally heavy - a lead casket - or metaphysically - a trinket from a material more attuned to its home plane than most) from A to B, allows someone to grab on/get in and go from B to A. Their pull towards B and 'planar weight' is far too insignificant compared to their vessel's pull towards A. * The planes are moving. People might be concerned to discover that world A is moving downwards compared to world B. The difference becomes small enough that B->A is possible at some point, and one day A->B might become impossible (and later yet, the same will happen to going back to B from A). * The difference is not that big. Someone, through accident or study, discovers that placing a mirror at a point of sufficiently high altitude (literal or planar) in plane B and its exit in a place of low altitude in plane A can allow B->A as well, or perhaps even invert the limitations. Perhaps this only works now and not earlier because the planes are in fact moving, and this is just the first symptom of the above scenario. [Answer] The planar travel is possible only if some particular restraints are met. Let's say that in the universe B there is a big abundance of metals in the environment, so that the majority of its inhabitants are slightly poisoned by heavy metals (think of mercury poisoning: it could also give an explanation of why the world B is a dystopic version of A). Planar travel is possible only if the person has "low content" of metals, otherwise he/she would simply slam against the glass; people of A have no problem, but people of B would simply contain too much of forbidden substances to cross the mirror. People of A, while in the universe B, would need to give big attention to what they eat, avoiding food that could contain metal, otherwise they couldn't come home. This would be a stimulus for the wizards of world A to improve the magic of the mirrors, reducing the limits that can prevent the travel, to the point that eventually even people of B will be able to cross the mirrors. [Answer] ## Balance between worlds Balance is a common theme in fantasy writing. People expect it. The swing of the scales between good and evil, physical strength vs magical power, etc. Of course mirrors have to be powerful artifacts to counter this. Powerful enough that only the people in A have really mastered it. ### One enters, one leaves Mirrors can allow the balance to shift temporarily. When someone (or more specifically, up to X people, depending on the power of the mirror) portals A->B, it can't be used again until it portals X people back B->A. ### The plot thickens This means people have to be careful with mirrors. If you portal from A, the last thing you want is for people to know you're from A. You want to get in, do what you've got to do, and get out. B is a dangerous place, and the last thing you want is to be murdered for your mirror. So this means it's not illegal or impossible for people to portal B->A, just hard and plot-dependent. Choose your own adventure from here :) [Answer] Think of high altitude acclimatization of mountain climbers, or people such as Nepali natives being accustomed to the oxygen deficiency (and their bodies able to compensate for it) far better than tourists who usually stay at sea level. Universe A is a world where the ambient magic quality is far different from Universe B, which maybe started off similar but then went through an apocalypse that caused mana depletion. When someone travels A -> B, they might find it harder to replenish magic from surroundings (though crystals etc. will continue to work). However, innately the living beings in A regulate the amount of magic they absorb from their environs so it doesn't overflow; while B natives have long lost the need and habit of doing so (because, there just wasn't enough to absorb). Now, if someone from B travels to A they would literally die by overdosing on mana from the atmosphere. ``` this restriction would need to be removed at some point ``` You can later enable inter-universe travel from B to A in different ways, depending on how common & uncontrolled you want it: 1. Acclimatization chamber (on B) or decompression chamber (on A) : Facilities are built for B's residents to get slowly accustomed to higher pressure/purity of ambient mana so their bodies can adjust to it. These might be expensive and controlled by powerful factions. 2. Spells/ skills to improve self-regulation: Denizens of A learn to balance the mana inside & outside their bodies naturally, while growing up. Someone comes up with a practice regime for people in B to learn those skills before they travel to A. [Answer] ## The Evil One Once, long ago, a great evil arose in Universe A. After a Great War, in which many heroic deeds were done and many horrible things happened, the mages of Universe A united in one last, desperate attempt to defeat The Evil One (whose name shall not be mentioned). They were unable to kill this being, but managed to imprison him in his home realm, Universe B. This prison is secured with seven great seals, kept hidden lest they be discovered and destroyed, freeing The Evil One to wreak havoc upon Universe A once more. Now, millenia later, the Great War is but a distant memory, and few people actually believe it happened, or that there ever was an Evil One. Dramatic progress has been made into dimensional travel, but the strange fact that only one-way travel to Universe B is not entirely understood. Experts suspect that it is caused by a magical shield, which is anchored somehow by physical objects, but they are not entirely sure how or why it was created. To solve this dilemma and to allow free passage and trade with the disadvantaged people of Universe B, they find an unlikely hero and his ragtag band of misfits, and task them with a great quest: to find a way to unite the peoples of Universe A and Universe B in harmony and great justice. Meanwhile, a Great Evil broods and watches, yearning to once more spread his malign influence over the delicious feast once denied him... [Answer] One such possibility is that the laws of physics are different between the universes, and universe B biology is incompatible with universe A physics. For example, suppose that Universe A does not have quantum tunnelling. Thus, the lifeforms there don't need it. If they travel to Universe B, they are largely unaffected. However, The lifeforms in Universe B depend on quantum tunneling. If they were to travel over, they would die, or face medical problems, as you decide. This gets somewhat easier to justify if magic is involved. There could be incompatible magics, much like incompatible blood types. [Answer] Explanation: The "magical lock" is actually placed on mirrors in Universe B by a secret order of humans tasked with preventing the other "savage" non-human races from traveling over to Universe A and obtaining technology that would be able to obliterate humans. Source of Magic: The source of magic in each universe is the combined wisdom and magical ability of all magic-wielding inhabitants. Universe A has many more highly adept magic users, owing to its relatively stable and functional society. The Lock: The strength of the lock is directly proportional to the magic abilities of the lock creator(s) and maintainer(s). In the case of Universe B, the human lock builders were very powerful and the secret order has maintained knowledge of and skill with magics that have been otherwise lost to the rest of the inhabitants. There has to this point never been an individual or group of magic users with enough ability to override a lock (many have tried). Killing one or more of the secret order diminishes the strength of the locks until/unless the order is replenished. Travel: Travelers from A->B maintain a magical connection back to the point of origin that allows them to return from any mirror in Universe B. In all but the rarest of cases, they do need to keep a talisman/device on their person that taps into the source of Universe A magic. The talisman temporarily unlocks (but does not destroy) any Universe B lock. The talisman itself is magic- and gene-locked, which means it cannot open a mirror portal without a willing, living magic user (i.e., no chopping off a hand or holding a gun to the talisman-holder's head). Resolutions: * A human from the secret order goes haywire and (magically or otherwise) forces the other members to release one or more locks. * A human from the secret order has a child with a non-human and over time, diplomacy prevails and the multiple species become allies. The locks are released. * A human from the secret order falls in love with a non-human and gives them a way to "overthrow" the humans. * An inhabitant of Universe A has a child with an inhabitant of Universe B. The child grows up with a connection to the source of magic in both universes. Whenever someone travels from A->B, the child is able to tap into the vast magic reserves of Universe A. Over time, they become the most powerful magic user in Universe B. * An inhabitant of Universe A has a child with an inhabitant of Universe B. The mother or father or both are killed at some point, leaving behind a talisman. The child's magic "profile" and genes match those of its parent from Universe A, allowing it to use the talisman. Anyway, variations on a theme. I hope something in here helps you. [Answer] Racism Humans in universe B have all existing portals to universe A. They refuse to travel to Universe A because they let all these subhuman species mingle together, also, they aren't terribly keen on letting their resident non-humans escape oppression via mass exodus through these mirrors, so the mirrors to Universe A are kept under close observation. Likewise, Universe A isn't too keen on being a destination for refugees from this backwater hell hole of a universe - all the humans are bigoted jerks, and if they started taking in the non-humans it'd get to be a serious immigration problem. Similarly, if any of their own people went over, their either weirdo human supremacists, or they were insane enough to travel to a world where their own kind is totally oppressed, so in general Universe A isn't terribly keen on letting anyone from Universe B pop on over. [Answer] Universe A might have a restrictive immigration policy Universe A has had the magic mirrors for some time and has had several incidents of people coming from other universes already. For whatever reason, the government in Universe A has decided that it would like to heavily regulate or restrict immigration or tourism from other universes. There are many potential reasons why any given polity would adopt a restrictive immigration policy. In no particular order: 1. Economic reasons (they're worried that they can't support more people / that them foreigners will took their jerbs!) 2. Public health concerns (does Universe B have diseases that nobody in Universe A has immunity to or expertise curing?) 3. Racism 4. Concerns about assimilation or culture (e.g. will people from Universe B speak the language and be able to find work?) Alternatively, Universe B could have a restrictive emigration policy Universe B's city sounds pretty awful, like it's run by a totalitarian regime of sorts. Totalitarian regimes often ban emigration to keep people from living somewhere better. Maybe they have a policy that prevents people from leaving their universe? Maybe the mirrors are totally illegal their and ownership of one is punishable by death or something horrific. [Answer] # Disease Control A long time ago, a B creature went to the A universe, but he carried a disease with him [they are asymptomatic carriers](https://en.wikipedia.org/wiki/Asymptomatic_carrier), millions of persons died by the plague. Since then, no people from the B universe is allowed to travel to A universe. People from A who travel to B universe are allowed to travel back after spending time on quarantine. If they don't die, it means they didn't get sick by the plague. Obviously, this is just a legal restriction if you really want you could travel illegally, or make a vaccine. # Energy Levels The universe A is at a higher level of energy compared to universe B. Travel from A to B is free, since you already have the energy. Instead, travel from B to A requires an extraordinary amount of energy/magic. [![enter image description here](https://i.stack.imgur.com/MyaMz.png)](https://i.stack.imgur.com/MyaMz.png) When a traveller from A universe who is in B universe and want to come back to its original universe (A) also travel free, since he already has in himself the necessary level of energy. Maybe, when an A person travel to B, all the energy released due the lowering of its energy state is stored, so when they want to come back to its home they just must spend that already store energy. If a B habitant wants to go to A he will need to spend huge amounts of energy/magic. [Answer] They are missing a spacial dimension, such as in the tale of [Flatland](https://en.wikipedia.org/wiki/Flatland) or Interstellar (2014 movie). Members of Universe A can interact with Universe B by ignoring their extra spacial dimension(s), but members of B cannot gain the dimensions that would allow them to enter or perhaps even properly perceive A. [Answer] Evolution of Conceptualization That an item can be enchanted at all is a concept that requires people to evolve spiritually and mentally enough to enable the enchantment. "A" people have spent countless generations becoming aware of this concept and gradually attained the ability at a societal level to easily enchant an item for travel to "B". "B" people are in a younger universe and haven't yet evolved to that level of conceptualization needed to make the enchantment work for them... or at least they hadn't until plot progression event X occurred. Perhaps event X was simply some "C" people that were tired of waiting for "A" people to next conceptualize travel to "C" and nudged things along. After all, all "C's" know that A + B tranposed by X = C. [Answer] # The great interdict Years ago, a world traveler from universe B brought a plague to Universe A. Smallpox, the black death or something more exotic. It wiped out a large fraction of the population, including the family of some of the post powerful mages. To ensure it never happened again, a great and powerful ritual was enacted to block worldwalkers from entering universe A. The ritual has a keystone that can be destroyed or individuals can be keyed into it or it can be otherwise bypassed by someone who knows about it and has access to the keystone. [Answer] The (non-scientific) energy level of Universe A is higher than Universe B. When someone from Universe A travels to Universe B either they have some sort of super power or their extra energy is locked in some manner. Someone (or something) from Universe B cannot travel to Universe A unless something fills them with enough energy to exist (not just survive) in Universe A. They also have to survive the energy influx. [Answer] The mirrors could be tools for projection into another universe, rather than strictly "traveling". This could happen behind the scenes, or could be an explicit part of the magic involved in mirrors. But for whatever reason, the no magic can truly connect two dimensions. They can only project things from the universe they're created in into another universe! Thus someone could walk into a mirror and appear on the other side - but there wouldn't really be a way to "get back" other than triggering the magic involved in the mirror's projection to cancel it. This could imply that all traveling is temporary, and is broken, with the traveling person killed or returned, when the mirror is broken. Or the mirror's mechanics could involve projection through enchantment or some other special means so that characters traveling stay in the Universe B even when the mirror is broken. Whichever way the specifics are chosen, this implies the mirrors only work to transport goods from the dimension they originate in to some other dimension. Then being able to travel from Universe A to Universe B could be as simple as "only Universe A's magic supports creating these mirrors". [Answer] Mirror travel is actually a magical tether. In Stargate, to dial from A to B didn't mean you knew how to dial back from B to A. You needed the coordinates of where you were going and the symbol of origin for where you were coming from. In the original movie, the team was trapped for a while because Daniel didn't know what to punch in for the return trip. So I think a reasonable explanation would be something like this: Someone somewhere came up with this mirror device and has them programmed specifically with the coordinates to get to B. To facilitate a return trip, it also provides a tether for that specific object to then return from B back to A. However, an object going from B to A without this tether will require its own mirror, with its own magical formula -- the "coordinates" of getting to A. Until someone on B figures all this out and develops such a formula, there is simply no way for an untethered object to get from B to A. They don't have the coordinates. There is no B to A link. This could be handy for some future plot devices too. Big Bad can't figure out how to dial from B to A but maybe he figures out how to steal someone's tether. Now that person is stuck in B and Big Bad gets a ticket to A. [Answer] Space is opaque in Universe B Matter in Universe B does not allow the transmission of photons. All inhabitants of Universe B are blind. They have no mirrors and cannot use them. [Answer] The biochemistry of Universe A is non-chiral, but otherwise similar enough that someone from UA can live on food in UB. A person from UB (our universe, with a lot of chiral chemistry) can visit UA but either must bring food with him, or slowly starve. <https://en.m.wikipedia.org/wiki/Chirality_(chemistry)> You can make this more general -- UA people can eat nearly anything that can combine with oxygen to produce energy. UB people cannot. ]
[Question] [ My family comes from a long line of well known tomb designers and my spouse is a part time tomb raider, we really are a perfect match! I explained to my spouse that a tomb is a very sacred place for the deceased to rest in peace and great care are taken to ensure that is the case for eternity, the talk went smoothly until my spouse asked about the puzzle part! In fact all tombs that were built by us had some forms of intricate puzzle going into the design, as if it is our signature, since no two puzzles are alike. So my question is why even bother adding in a puzzle if we really don't want anybody to disturb the place? I mean, come on: everyone likes solving puzzles and we are sending out invitations every time we build a tomb! Anyway my family motto is curiosity kills the cat and people, call our toll free hotline 1800-ILOVETOMB to design a custom made tomb with thousands of handcrafted puzzles of your choice now or to reset the puzzle. [Answer] For three reasons: 1. you build the tomb on the behest of the owner. You still need to add their body and all their possessions to the tomb later! So you want a lock that can be opened to do your job. (And no one messing with the tomb in the meantime). 2. a bit the same as 1. The original tombs were for rich dynasties, and as such many dynasties wanted to be buried in the same tombs. It is rather hard to do that if you can't ever enter. 3. those deadly traps don't repair themselves you know! There's only so long your carefully weighted stone pressure plate and intricate mechanism can remain operational and someone has to re-apply the poison on the poison darts every now and then. It has the added bonus that you can maintain the tomb and make sure the eternal resting place remains eternal. Hell, who do you think hauls the giant boulder back into position and replaces the "priceless" artifact after some whip-wielding cowboy hat got crushed trying to take it? It's a poor design if every trap works only once and the next tomb raider just waltzes in. [Answer] # To Keep the Looter Occupied While the Poison Takes Effect: The only truly sure way to keep a tomb un-looted is to put no goods in the tomb worth looting, or hide it so well that no one even knows it exists. This is how Tutankhamun managed to go un-looted: The priests hid the tomb because of Tutankhamun's heretical father. He was meant to be forgotten. But the dead need grave goods, and their tombs are supposed to be available for homage. Sealing the tomb won't keep out a determined tomb robber. There's got to be a way to make this work! A determined looter who has no clear way to get into the tomb will smash their way in, destroying the tomb and disturbing the rest of the dead. But your tomb is full of subtle poison leaching out of the ground, and the looter will soon be a corpse as well. The problem is, the tomb is poked full of holes by the tomb robber before they die. They might even dig a new shaft all together, and possibly LOOT the tomb before the gas builds up and kills them - too late. Eventually, looters will poke enough holes in the place to provide good ventilation, and the poison will stop working. So a puzzle promises an easy way into the tomb that doesn't involve all that hard digging work. Why would you dig your way into the tomb, when all a smart tomb robber has to do is solve the puzzle? And what tomb robber doesn't think he's smarter than the fool that left a puzzle instead of just sealing up the place? The Puzzle takes at least a few hours to solve, even for a clever robber. The poison makes your mind foggy after an hour, slowing you down. After two hours, they leave to let their head clear. Maybe they'll work out the puzzle in their head and come back tomorrow. Then the tomb robber takes a nap and never wakes up. With each death, the tomb gets a reputation for being cursed. But the robbers often die in their sleep, so it's not like they were killed in a trap, right? That's one bad curse. Better reconsider looting the place. Redundancy may also mean that the puzzle itself is coated in a contact poison. The foolish thief will touch it and die quickly. But the clever thief with gloves on is once again sure he's smarter than any puzzle maker and has bypassed the trap. An actual curse (if available), anthrax spores, or a room with really clever and bad ventilation will also kill those clever enough to sit and work out the puzzle. A really mean variation is to make the puzzle spell out a message as you solve it. "If you can read this message, you're already dead." [Answer] ## It is a recruiting scheme Yes, the rest of the dead is sacred and so on, but what really counts is the success of the still living family members. For generations, your family has highly valued ingenuity, logical thinking and a daredevil attitude to dangers and challenges. Unfortunately, such qualities are hard to find among the common people. So one of your ancestors made sure it became well-known that the tombs of your family are filled with riches and protected by fiendish puzzles. Those who manage to solve the puzzles will be met by a price, but also an invitation to either work for or eventually even marry/get adopted into the family. As a bonus, they are almost certainly interested in tombs AND puzzles, making them ideal candidates to continue the family trade. [Answer] 1. False hope. If the prospective looter has a choice between a year's toil digging a new tunnel, or "just" using an existing one, they will take the path of least resistance. Backfilling just makes it a matter of time. Instead, let people think this will be easy, and kill them along the way. (If they find the tomb at all. Random bits of hostile desert/jungle/tundra with no good landmarks make the problem moot.) 2. Victims. It's hard to resurrect the Dread Lady without the proper blood sacrifices. "Halldir's Cairn" of Skyrim (I think that was the name) used the occasional intruders to gradually power a resurrection ritual. 3. Tenders. Your tomb needs to be entered regularly by someone who's supposed to be there. The puzzles are actually combination-locks with a fail-deadly approach. Any hints about the combination are discouraged, but you can't really enforce "no writing passwords down" once you're dead. And the moment those "hints" turn up, the lock becomes a puzzle. [Answer] ## It is a game show Motion detector alert in the tomb of Count Dibbler the Third. Will the bold-faced adventurers manage to loot the tomb this time? Or will they fail to solve the puzzles and succumb to the terrors within? For just 500$, you can gain access to our live stream from inside the tomb! Also check out our premium packages, where you can personally release the swarm of flesh-eating scarabs if they choose the wrong idol to turn! Real tombs, real treasures, real death! Your tombs are secretly filled with sensors and cameras that transmit the endeavors of would-be tomb robbers live to an elite and paying audience of thrill-seeking rich people. The odd looter who actually makes it through the puzzles is a small price to pay compared to the enormous earnings your family makes from the tickets. In particular, if there are trackers within the stolen treasures which assure that any thieves will get an unpleasant visit a few days later. [Answer] # Religious Compulsion The local religion strongly values battles of wits, down to venerating the winner of the bi-annual chetetriops tournament with a bas-relief and a year's worth of grain. So the more important you are, the greater the pressure from the priesthood that your tomb be the ultimate battle of wits. Puzzle designers work up the most intricate designs to adorn the most important tombs, and discuss the answers with a member of the priesthood, sworn to silence, to ensure that they're not simply escape-proof deathtraps. A chance must be given to whoever would brave the puzzle to prove their worth, no matter how remote. And so the biggest, grandest, most important tombs are absolutely festooned with intricate, lethal puzzles, to better demonstrate to the gods how very pious they are, and how they deserve to solve the Great Rubik's Cube in the sky. [Answer] ## Because one day, the worthy dead will be physically reincarnated It has always been believed that the worthy (i.e. the rich) will eventually live again. But some time ago, an ambitious young priest revealed a prophecy that changed people's expectations. You won't get resurrected in your old body - instead, you will be reincarnated in a new one, and the God of the Dead will deposit it gently outside your tomb. This was very reasurring, for people who were worried that they would be stuck inside for eternity. One-way doors and passages had always featured in tomb designs to let you out, but they could still jam or collapse, and trap you. Instead, there was now a problem of allowing the treasure's legitimate owner back into the tomb to collect their wealth. The simplest way would be a massive combination lock, but the priest warned that the memory could be rather hazy after living in the World of the Dead for years, and so you had better include plenty of aides memoires to help you remember the passwords. Or perhaps puzzles that would be easy for you to solve, but hard for anyone else. After all, you are a smart noble, whose wealth is proof of your cunning and intelligence; and they are mere grave robbers, whose poverty proves that they have neither the brains nor the can-do attitude that they would need to solve such fiendish traps. Tomb builders saw business thrive, although many an architect was given a headache by trying to invent puzzles that looked impossibly hard, but were still solvable by a royal family who had been making life very easy for genealogists for several centuries. And funnily enough, that young priest who started this whole business, ended up doing rather well for themselves too. Nobody was quite sure where their money came from, but it was probably just their winnings from repeated triumphs at the all-Kingdom crossword, sudoku and logic problem championships. [Answer] # Don't reuse passwords You want to keep people out of the tomb. One primitive idea is to give the tomb very thick walls, but people can dig through stone given enough time. You need to make getting into the tomb dangerous. So you add some traps. At first, you just reuse the same trap over and over. You have a keyhole, and if you put the wrong key in it a trapdoor opens beneath your feet. You build hundreds of custom tombs for hundreds of happy customers. Then, one fateful day, some tomb raiding youtuber figures out that if the trapdoor has more than a tonne of weight on it, it can't open, and the lock disengages when the trapdoor jams. It's a gold rush, as hundreds of tombs suddenly are ripe for plunder. So you have a new policy: never use the same trap twice. Your traps get more and more convoluted and bizarre, making it safe to assume that even if one tomb is raided, the others will be safe. You also probably want to give the family access, and if you give one family info on how to open their tomb, you don't want them to get an idea of how another family's tomb works. So every bespoke tomb has to have a bespoke lock. [Answer] The puzzles aren't to keep people out, they're there to keep the dead in. Tomb builders are all scared of a zombie apocalypse. So in order to get out of the tomb (and, inadvertently, into the tomb) the tomb builders construct elaborate traps and puzzles. They make them nice and difficult to solve just in case dead people are actually still smart. It lets them to sleep better at night. Of course, the downside is that every tomb robber and his uncle wants a crack at solving the puzzle and getting the loot, but tomb builders will take that over the walking dead. [Answer] > > I mean come on everyone likes solving puzzles ... > > > Hmmmm... I'm not that sure, unless you have way to respawn me in the event of death caused by the making a mistake while solving any of the puzzles. Because if I'm left dead by mistake, as sure as death and taxes, I'll keep my software engineering job - way safer this way, even if I get to pay taxes on the income. --- Point: there's never 100% security, security is a trade-off between the cost of raising a meaningful defense and the cost of the attacker. The only thing one can do is to increase the cost and/or the risks of an attacker way beyond what the (choose-your-percentile) of the would be attackers are still motivated. In the current context, if the security of the tomb is paramount, then the solution is to seal the tomb for anyone (so, no puzzles to get around, only brute force will get inside. Bonus points if the level of force required would destroy the value of the price inside). But I suspect it is even more paramount to let some authorized persons to get in regularly, so obstacles that can be disabled for those with authorization need to be provided. Deadly puzzles would fit into this category [Answer] They aren't exactly puzzles. As you say, tombs are build on the premise that nobody should disturb whoever or whatever is inside. So, what you put inside are deadly traps that would add to the collection of the tomb the corpse of whoever tries to get in. But, of course, as intrincated and complex your traps might be, there will always be a way to pass them, break them, or cause malfunctions. So, it's not that they're made on a "challenging" way on purpose; it's just the annoying adventurers that love challenge and a way to prove that they can surpass any challenge you can put in front of them. [Answer] ## It's never really about the dead The puzzles are basically the front door lock for the people who continue to use the tomb on a daily basis (and maintain the traps). Often they would be cultists or religious people/groups claiming to represent the entombed or his lineage. Sometimes they may be using the secure inner sanctum as a vault, or sometimes they may be using it for rituals. Either way, the traps keep out the unwelcome, while allowing the authorized to pass. [Answer] 1. Because you have thought of a really cool curse, but you don't want to waste it on people who aren't smart. So your puzzle keeps thick people out of the tomb. 2. Maybe your curse is subtle: you don't want to waste it on people who are dumb. For example, what if your curse causes their higher mental facilities to fail gradually, starting with their puzzle solving skills? Dumb folk won't be able to appreciate what is happening to them. 3. Maybe fulfillment of your curse costs you somehow, so you don't want people to run into it unnecessarily. Perhaps it costs you energy, or you have sold your soul for the fulfillment of 13 curses? 4. Fulfillment of your curse has been outsourced to a zombie, who eats the brains of the tomb robber. But your zombie is a snob, and he refuses to eat the brains of anyone who isn't smart enough... [Answer] To allow access to the guardians There is a sect that is in charge of protecting and maintaining the tombs. ]
[Question] [ Some dwarf lore, particularly the video game Dwarf Fortress, depicts dwarves not just as aggressively alcoholic, but as a species that functions better when drunk than when sober. That they need alcohol to get through the working day the same way a human might need caffeine. Now, the easy way out here is to just depict dwarves as acting drunk when sober and sober when drunk, but to me that seems rather boring, and I have an alternate concept I'd like to explore: what if dwarves, without the aid of alcohol in their system, acted too sober? What if the alcohol was used to stave off something equally but oppositely debilitating about their normal brain chemistry, something that alcohol brought them down from? If having alcohol in a dwarf's system allows them to function like a sober human, then what parts of their "excessively sober" brain chemistry could they be using the alcohol to deal with? [Answer] ## Depressants Firstly, alcohol is a depressant. The chemical interaction with the brain basically slows down parts of it, which in humans, impairs things like reflexes, motor function, perceptive functions, etc. It also releases some psychological functions, such as the behavioral moderation that is common in sociological interactions. With less moderation, individuals tend to be more open in interactions, sometimes for better, sometimes for worse. When considering these aspects of alcohol, there is definitely a character scenario for which alcohol would be helpful, and I think we can look to the very thing that Dwarves are known to be best at for guidance. ## Perfectionism Dwarves in every medium and story are master craftsmen. There are a couple of aspects that are key to crafting: repetition and a detailed eye. For basic material work and preparation, repeating systems that are meticulously tested are key. Alloying metals is a science that requires many tens or hundreds of hours to perfect, and then must be done the same way to maximize consistency in results. There are many other tasks that require the same level of perfect repetition to craft incredible works, especially larger ones, such as massive gates and structural metal work. When it comes to making intricate items, a craftsman must have an uncompromising vision and eye for detail. Similarly for weapons, a single small defect can cause a weapon or armor to fail under stress when it matters most. Dwarven weapons and items are generally known to be near perfect examples of material work. These factors lend themselves to an entire fantasy group that is given to perfectionism and potentially, as a cause of said perfectionism, general anxiety. ## Anxiety Perfectionism can be driven by a tendency to fear the worst from “underperforming.” Indeed, in my earlier comment on weapons and armor, I mention how minor defects in those things can cause failure at bad times. However, the entire species seems to tend to be surly and grumpy. In growing up with parents and family members that are perfectionists and grumpy, it would make sense that individuals would adapt to become anxious and perfectionist as well due to being exposed to negative consequences for failure during the learning phases of life. Experiences that cause that sort of perfectionism and general anxiety for failure could certainly make for excellent crafters; however, those experiences could also lead to crippling anxiety-driven behaviors, such as avoiding contact with others, choice fatigue and paralysis, and adrenal fatigue. ## Side Effects of Anxiety Of the many side effects of extreme anxiety, fear to make and maintain relationships is especially detrimental for a society. Without the drive and desire to be and work with other members of the society, it would eventually collapse. Cultural isolation leads to infrastructure degradation, supply problems, and other connected mental health issues. For reference, see the isolation caused by the response to the COVID pandemic. This sort of scenario goes a long way to explaining the dwarves general sense of isolation and grumpiness, and especially around other cultures, since Dwarves as a society might see any potential inability to be perfect as a stressor, and external cultural relations tend to be more tense than internal ones. On a more individual level, choice fatigue and paralysis occur when every decision is burdened with anxiety and makes making future decisions harder and eventually impossible. Individuals experiencing decision paralysis will seize up when asked or forced to decide on something. The will either not respond or present apathy (“I don’t care, it doesn’t matter to me.”). This can lead to all sorts of personal and social issues, such as poor time management, avoidant behavior, and the inability to make functional, rational decisions. Adrenal fatigue arises when an individual is constantly “on edge” to the point that their body’s endocrine system can’t produce enough hormones for normal function without sparking the “fight or flight” response. The physiological consequence of this tends to be an apparent lack of motivation to engage in basic life tasks such as cooking, cleaning, and productive work. If a whole society falls to this, then it would be catastrophic for the long-term outlook of the group. A society facing an extreme version of this anxiety-based perfectionism would seek any method for reducing mental stress, and one particularly available substance immediately comes to mind. ## Solution: Alcohol Drinking alcohol on a moderate level in humans (1 to 2 standard drinks per day) has been know to decrease adrenal response, encourage social interaction in a positive way, and promote more sound sleep. In Dwarves, who tend to have a higher mass despite being shorter, this moderate drinking level would be higher, more akin to what we are familiar with in media. In short, if Dwarf culture drives all of them to have a crippling general anxiety disorder, then alcohol would be the self-medication that is cheap and readily available to all, and thus promoted within the culture and imbibed frequently. ## Answer: Excessively Sober Now, to actually answer your question an "excessively sober" Dwarf based on the above causes would likely display a few key characterizes: * Generally avoidant of others, seeking isolation and safety at almost any cost. * Nervous and anxious behavior that is dysfunctional in the immediate sense, it keeps them from holding conversation and focusing on tasks that are immediately important due to a general since of anxiety and fear * Mood instability driven by noticing any perceived imperfection, i.e. if they notice that someone hasn't put something away properly or made some similarly small mistake, the Dwarf might immediately engage in anger displays * And/Or people-pleasing behavior, seeking to ensure others are happy and satisfied with their work and presence, for fear of angering the other individual through imperfection or failure. [Answer] Someone already had this idea -- it's called [knurd](https://wiki.lspace.org/Knurd) and was invented by Terry Pratchett in his Discworld universe. It's basically described as feeling stripped of any comfortable illusions one might have had before and seeing the world as bad as it is. [Answer] If they are like humans, they would suffer alcohol withdrawal. [Introduction to Alcohol Withdrawal](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761824/) > > Despite the variability in the type and severity of symptoms that a > person can experience, the clinical syndrome of AW has been well > defined. Its symptoms generally appear within hours of stopping or > even just lowering alcohol intake and, thus, BAC. The most common > symptoms include tremor, craving for alcohol, insomnia, vivid dreams, > anxiety, hypervigilance,2 agitation, irritability, loss of appetite > (i.e., anorexia), nausea, vomiting, headache, and sweating. Even > without treatment, most of these manifestations will usually resolve > several hours to several days after their appearance. > > > The most severe manifestations of AW include hallucinosis, seizures, > and DT’s (see also the figure on pp. 63, from Victor and Adams’ > classic paper). > > > Hallucinosis, which may occur within 1 or 2 days of decreasing or > abstaining from alcohol intake, is a complication distinct from DT’s. > Patients with alcohol hallucinosis see, hear, or feel things that are > not there even though they are fully conscious and aware of their > surroundings > > > Alcohol withdrawal is what really happens when people who drink a lot suddenly stop, but to me it seems pretty grim for a fantasy with dwarves and leprechauns and stuff. Alcohol withdrawal can be fatal. [Answer] To expand on Arne's answer, imagine the effects on society if people could easily see through any politician's promises, see the falseness of a boss's promise to take care of them, or see the real future for anything they make. Societies offer promises so that people work together. People make things of beauty with the hope that it lasts for a while. Yet, the reality is that politicians can't deliver on their promises. The boss doesn't give the raise you need. Swords that were crafted in beauty are left to rust on the battlefield. Everything wears out, erodes, or rusts. Think of the effect of accurately seeing the future of everything you do. What's the use of working so hard when everything we hope for doesn't happen? The Tibetan sand mandala and the way that it is built for the moment and destroyed is an expression of how everything is impermanent. <https://en.wikipedia.org/wiki/Sand_mandala> Another thought is that alcohol has a calming effect on their bodies and without it, they are so hyper that a child on stimulants could be considered mild. That would make them unable to have a society unless they were "drunk". [Answer] One relevant fact is that there are a lot of humans who need alcohol in order to get by: namely, people with physiological alcohol dependence. For the sake of convenience, I'm going to call physiological alcohol dependence "alcoholism" (even though the word "alcoholism" can also mean a psychological dependence on alcohol, or a habit of drinking too much alcohol, or a combination of these). When humans drink a lot of alcohol, they eventually develop alcoholism. Once they do, they suffer from symptoms of varying severity if they stop drinking (or even if they drink "too little"). As mentioned in [Willk's answer](https://worldbuilding.stackexchange.com/a/237087/7862), these symptoms can include anxiety, headaches, seizures, and even death. So, in your case, I think the most important difference between humans and dwarves is that dwarves automatically have alcoholism. Whereas humans develop alcoholism by drinking a lot, dwarves are born with it (or they develop it at a very young age). Humans who stop drinking eventually become cured of their alcoholism, but dwarves who stop drinking never overcome it, just as humans who stop consuming vitamin C never overcome their need for it. You get to choose how severe a dwarf's withdrawal symptoms are if they stop drinking. At one extreme, dwarves who stop drinking invariably die. Somewhere in the middle, dwarves who stop drinking suffer severe symptoms at first, and the symptoms gradually become mild, but never go away. And at the opposite extreme, dwarves can become teetotalers pretty easily, but the vast majority of them consider it to be a pointless effort. [Answer] Lubricant But not of the social variety. Some lubricants use alcohol as a component. The bodies of Dwarves don't break down the alcohol. They have evolved (or were created by their god, as per the setting) to redirect the alcohol to their joints. It keeps them limber, literally. A Dwarf who does not drink enough has symptoms similar to extreme arthritis. If they go long enough without alcohol, they might even become unable to move. Disinfectant Similar to the above, Dwarves bodies do not break down alcohol, or at least not quickly. Instead, they keep it in their blood. It helps them fight off various bacteria and viruses. This is part of the reason Dwarves are known to be such a healthy race. Of course, the downside to this is that a 'sober' Dwarf is much more vulnerable to illness. [Answer] This is totaly whimsical but you could imagine that dwarfs benefit from : Epilepsy Mining is hard work. Sometime you find something (gold...) but most of the time it is mostly repetive stone breaking. But dwarfs have a secret. They are geneticaly subjects to a certain type of epilepsy seizure : [clonic seizures](https://wikem.org/wiki/Seizure_(peds)), which are caracterized by repetitives compulsives mouvements, especially their arms. These seizures are greats to mine without even thinking about it. To be abble to easily trigger it, they have to lower their [seizure threshold](https://en.wikipedia.org/wiki/Seizure_threshold). Alcohool is a very good solution for that and therefore dwarfs are always drunk. When they want to trigger the seizure a small "mushroom" is then all they need and here we go for a mining session... ]
[Question] [ This question already has answers here: [Resources to justify long-distance space mining missions](/questions/15364/resources-to-justify-long-distance-space-mining-missions) (17 answers) [How would Earth-Mars trade work with a Musk-like colony?](/questions/1064/how-would-earth-mars-trade-work-with-a-musk-like-colony) (8 answers) Closed 7 years ago. Think about the Nostromo from Alien. A giant freight ship that transports iron ore (!) over many light years (passing several other systems) to Earth on a year long trip. I think most will agree that it makes nearly no sense at all. Iron is abundant on earth and even if not it is abundant on nearer bodies in system or nearby systems (I think). I think this is true for most raw ores (except for plot device unobtainium) so there is no sense in this kind of mass transport between the systems. Unobtainium that is only found in one or several systems aside, and scenarios aside in which FTL transport is zero cost and instant (or nearby) which goods make sense to be transported over vast distances in space? Are there some resources that make sense to be carried in giant transporters? Examples I can think of: Information : If you don't have FTL communications and information must travel with ships, it will be a very common good to transport. But it does not need big cargo rooms, so small ships (or even unmanned probes) are enough. Very valuable (or important) manufactured goods, that cannot be produced at the destination. But if the destination (poor frontier colony) can't produce it, can they pay for it? Art, special luxury food or other luxury goods for the rich. And of course - people (who can pay for it). So, no chance for our Han Solo like smuggler (except in this small niches) and no chance for our giant Nostromo like space hulks? Edit: I agree that there is much intersection with the "duplicates". But I think the overwhelming mass of good answers is a very good information source. Perhaps the other two duplicates should link back in some way to here to provide additional and related answers? It's hard to decide which answer to accept. I would accept several of them and share the points, but this is not possible. So I accept the most popular answer, despite getting good ideas from several other answers, too. [Answer] Things that are unique Whether it's a mineral, a plant or an animal, the only place you know you can find it is `<insert planet name here>`. Well you have to import. Alternatively, it is a manufactured good, produced by one company, and that company has only one manufacture. Likely they won't bother building a factory on another because there isn't a big enough market for it. But there are still people ready to import it. Or even alternativelier, you can find a similar product, but you want/need that exact one for reasons. Things that are really, really valuable, like, a lot Or more accurately, you can sell it at a high enough price that you can cover logistics cost, but not too high that nobody will buy it. Ties in with unique really, since anything unique tends to be really expensive as well. If you have to import it from an exotic location and the shipping fees are ludicrous, it only adds to the intrinsic value bragging rights. Rich people typically only care about the price tag. Art is undoubtedly better when it traveled 42 parsecs. Things that are kind of legal but not really Maybe obtainium is extremely easy to find but extremely hard to acquire. Reason number one would be paperwork. If it's regulated up the wazoo then maybe it's easier to acquire illegally. Or if you are up to no good, you don't want the paper trail. Reason number two would be taxes. Maybe your corporation can bypass customs (legally or not), so that shipping fees plus import tax is cheaper than just buying it locally. Or maybe you need it faster than the red tape will allow, so you have to turn to other sources. At any rate, it's probably easier to covertly and illegally import things than covertly and illegally mass produce them. Things that are actually people People like to travel too. Though that depends if you count people as goods. --- So to sum up, things extremely unique/niche or things extremely sublegal. As for why giant transports, there's a reason we build ginormous boats to carry loads of containers, it's because the bigger the boat, the more cost effective. It helps bringing your revenue up and your shipping costs down. [Answer] ## Manufacturing equipment Massive-scale manufacturing equipment would take too long for a colony to work to on its own. 20 years at sublight to get a massive orbital construction facility created by much more massive construction facilities in home system, or 50 years a small one yourself. Comparatively, may be cheaper due to pre-existing large-scale on homeworld. ## Valuables Family heirlooms, crown jewels, things that have social value. ## Damaging-to-extract minerals Some highly uncommon minerals such as massive quantities of uranium and plutonium (mine in one system without life, strip-mining barren worlds, transport to planets with a lot of life where land is protected.) ## Energy Assuming some form of energy storage much more efficient than batteries is created, solar systems with no planets can have solar arrays that can blot out a sun in a dyson swarm without risking planets. Then energy is transported. If effectively unlimited storage, storage containers would be of assorted value based on how much energy is in them, and likely not in single containers for assorted market values (and so you don't have to combine everything in the swarm each time, just replace storage and from parts of swarm and continue. ## People Not just "those who can afford the trip" but those who are worth getting on the trip. Highly skilled doctors, architects, those of political value, etc. And they may actually be cargo if they're put into some kind of stasis for the duration of the trip. ## Robots Hey, manufacturing equipment and people rolled into one! ## Military Equipment Yea, you don't just send that stuff or the plans for that stuff flying around unmanned. And when you need an army 'now', just sending plans isn't good enough. ## Transportation Not transporting people, transporting transportation devices. Delivering stargates if your story has that kind of thing, larger ships that destination can't produce, etc. ## Specialty goods It's patented and protected by encryption software or something and everyone relies on them. Gotta have actual manufacturer goods, and they don't have a plant on the target planet. [Answer] Stars and star systems have a [metallicity](https://en.wikipedia.org/wiki/Metallicity) measure attached to them. Much to the despair of chemistry professionals, astrophysicists will call any element heavier than helium a metal - so we are not only talking about iron and gold here, we are also talking about carbon, nitrogen, oxygen etc. Our galaxy is rich in astrophysics "metals" in the core, and in its main plane. In general, the further you move away from these, the less "metals" you have. [![Metal gradient in the Milky way](https://i.stack.imgur.com/eB4ca.jpg)](https://i.stack.imgur.com/eB4ca.jpg) [Source](http://www.sdss.org/surveys/segue/) So if you are going to colonize the rim of the galaxy, and if the star system you are going to has only hydrogen and helium... It might be cheaper to bring your own shipments of the periodic table than to convert the local "non-metals" into heavier stuff. I believe it to be cheaper because usually most of the "metals" we are talking about here are formed in the core of stars when they go Nova. That may take more energy than a ship could provide. Now the only piece of the puzzle left to solve is why someone would want to colonize a piece of the galaxy that has nothing valuable going for it. Well, maybe there is a wormhole there, or maybe it is an important passageway to somewhere else (i.e.: a star system right in the middle of two galactic arms). You may want to build a permanent station there. If all you can find there is H and He, it's a good idea to bring your own building material. [Answer] Maybe sometimes it is cheaper/easier to buy goods from another solar system that to actually produce it. We can draw a parallel with our world, where for example Western countries could technically produce coffee in heated green houses, but it is more convenient to buy them from South countries and wait the goods to come in super tankers. Super tanker are expensive but it is still cost efficient to use them instead of producing coffee locally. For the Nostromo, maybe it comes from a place where it is really cheap to produce iron ore (cheap workforce working to extract iron ore on a planet entirely made of iron ore for example...). Then for big bulks of iron ore it can be worth to pay the transport of the goods. [Answer] ## Almost nothing In a strictly economic sense you're looking only at high value manufactured goods from specific regions. Consider the [small wooden statues](https://en.wikipedia.org/wiki/Easter_Island#Wood_carving) from Easter Island for example. These are reproduceable, but have no value unless they're original and historic. Also as mentioned by AiX: Biological matter, probably in egg/seed form to minimise cost. Unless you can justify moving entire historic buildings, like say, a pyramid, you're going to struggle to justify enormous bulk freighters. Han's style of small ship high speed runs are going to be the bulk of cargo. ## So you want a giant bulk carrier This is not impossible if you run it on economy of scale. First make haulage of small items by ordinary people cheap, really cheap, £0.50 for a letter cheap. You'll also need to make moving people equivalently cheap, people need to be moving around to want things from home and to want to send things to people far away. Now, when someone posts something to a family member far away, that letter goes to a planetary hub, then to a sector hub. Between high population sectors you get your big bulk mail carriers. Sentimental value is what can drive your bulk freight, not commercial value. [Answer] A simple way to allow bulk transport would be to include 2 factors in your universe. 1: make it cheap to get to space, think some kind of antigravity drive which can get things to orbit for little more than the potential energy difference. No big expensive rockets. It can be very slow if you need an excuse to include big expensive rockets for military stuff etc 2: I gather that your universe allows FTL. Make the cost of FTL high and flat rate. Whether the thing entering FTL is the smallest engine with the smallest hull or a supertanker with an FTL engine bolted to the side, make ftl cost the same. The same quantity of unobtanium crystals get burned up or similar. If each interstellar journey costs 10 million credits whether you're transporting 20 kg's of hard drives or 2 million tons of cargo you're going to build your ships big and if getting to orbit is cheap enough you can afford to ship lower value items. With these adjustments you can transport almost anything of reasonably high value. [Answer] There is something others have failed to mention so far. Common goods not readily accessible by colonies. Starting colonies, or even somewhat developed ones are bound to lack the industry for producing a massive amount of goods and technologies. The amount of logistics needed to develop most modern technologies is immense. For a modern smartphone you need a number of mining industries to extract numerous metals from the earth, you need a chain of specialized industries to develop the components en-mass, from batteries to transistors to screens to wrappings. You need industries for inks, speakers, glues and a bunch of other elements. you even need industries to develop software and apps. A colony ranging from small to medium sized is bound to lack some industries that are essential for the manufacture of many modern technologies, as such, they either have to import the resources or the finished product. Given this need to import stuff even when lacking a single component, it's probable that colonies will import the finished product until they are capable of building the entire chain of manufacture. [Answer] One of the biggest motivators of interstellar transportation and shipping would be war. In a multi-solar system conflict where many planets are struggling to survive, the planets on the front lines would be unable to manufacture and maintain the weapons, ammunition, defenses, and soldiers that they would need. This scenario has a lot of parallels to World War Two. Before America had entered the war, England was struggling to meet the bare necessities required to keep on fighting. England was so desperate for things like fuel, guns, and rubber that it was willing to look past the money and put itself into debt. On the American side, despite thousands of ships getting sunk by U-boats, the trade was lucrative enough to keep people coming. War causes desperation, and in a multi-star conflict there would be a huge amount of trade with things that would usually not be worth shipping that far. [Answer] ## Energy It makes sense to transport energy in enormous giant GIANT transporters. Some tasks have a need for lots of energy. For example disassembling a star, or moving a planet as can be seen in this [example](https://worldbuilding.stackexchange.com/a/45273/20315). There are other tasks, which may need lots of energy, too. For example just for living if you have a big, I mean really BIG, human population, or for supplying a big big big AI for solving some universe problems (even if it's a quantum computer and a very efficient one - it may need lots of energy). If they were stuck with some possible thermonuclear reactions and can't burn everything in an efficient way, by time or mass of the reactor. It might be the case some reactions are just slow by nature and it needs time and energy to find good efficient solutions for them. Stars are not efficient actually (hm except supernova's), so we can't just copy them, we have to invent something. Stars are not efficient in terms of total mass required for their existence vs power flow they are producing. Building an FTL drive may require lots of energy. Not to produce the parts of it, or for the fuel supply, but to pump it with energy up to a level where it begins to work. See [Alcubierre drive, energy requirement](https://en.wikipedia.org/wiki/Alcubierre_drive#Mass.E2.80.93energy_requirement) for a reference. Some mass of construction of a reactor, where such reaction will be placed, even if it is 10kg per 1GW of power, it may be a lot of mass and volume of such mass for a reactor with star-like power productions. The best I can imagine at the moment is 1t per 1GW, mass/power ratio. Such a ratio (if possible) would allow us 10 times more energy generation, with materials we already have in our system, than our sun produces. It may (or may not) be a better ratio on a larger scale, in giant giant reactors, but still: it will be a lot of mass. As a result * fuel they burn, and constructions where they burn it * mass needed to build such constructions. Carbon for example, for the enormous large scale of energy production - it needs lot of it. As a note I'm not sure what my definition of enormously large and enormous power production is. When I talk about disassembling planets, on my scale it's just an industrial task. Although even that task needs enough energy. Probably this is enormous big for me: [Laniakea Supercluster](https://www.youtube.com/watch?v=No0omeHIxwo). Yes, definitely enormous big. [Quasar](https://en.wikipedia.org/wiki/Quasar) - not bad, not bad, I like it. ## How big? One day of work for our sun is something like cub 70X70X70 km of a liquid He3+D mix. Stars are good sources of such isotopes, so it makes sense (maybe) to transport them from stars. So if we need to increase our energy production by 0.1% of the Sun's energy, we may consider to send and receive 7x7x7 km shipment each day. (It may be solved another way, so it's valid for way much more energy bursts). Or we may send such ships to setup another system for energy productions and ship building. If we will be able to build just one FTL ship (which do not need [rails](https://en.wikipedia.org/wiki/Alcubierre_drive#Placement_of_matter)) with our non-FTL capabilities, the entire galaxy will be ours, in less than 2000 years(humanity may grow fast enough to require all energy produced by all stars in a galaxy, if a possibility for the grow is given). ## Distance Behind that are some calculations, involving possible human population grows etc. But up to 1,000 light years, there are easier, non-FTL ways, to transport energy. But for farther distances, FTL transporting of energy will be very handy, if that's possible. And if the engine needs much energy just to start functioning, maybe it will be the exact time when we, if we can afford some, get one of these. P.S. So there are some reasons to transport some forms of mass. It's true even if you are able to transmute elements efficiently, and true if you can't. So if you look at that Fe transport like description of transporting X-type construction material, and no unobtanium, just regular matter (Carbon for example), it might make sense, but not because of the labor costs, not because it's cheaper, easier, whatever, but because you have to, because there is no other way to get as much as you need in that system. So in OP's example, it's not a problem of what they are transporting, but a problem of the scale they operate at - it's not big enough to be viable. But as these ideas were mostly formed in 60-70's and earlier, it might be forgiven for old stuff - harm has already been done and what we may hope for, more good was done too. P.P.S. Cheaper production in a nearby system, if the production of one FTL drive will cost something like Jupiter's mass of energy, even if future operation will cost no energy - do you really think transporting some goods will be worth it to use FTL for when there are tasks for the civilization as a whole to solve? Transporting people is one of them. I like that part of AmiralPatate's answer. P.P.P.S. [Chthonian planet](https://en.wikipedia.org/wiki/Chthonian_planet) - an interesting type of planets (very close to sun orbiting gas giants). There have to be lots of unusual isotopes, made by neutron flux from the star. [Answer] You should also look at the other side of the equation. The cost of import is so high because of limiting factor of "energy". If you had unlimited energy then even iron becomes a viable import. Of course, if you had unlimited energy, then we could just "poof" more iron into existence but.... So lets assume you have unlimited energy, and a short supply of something. Importing would make sense. Given a method of travel that takes "normal" amounts of energy (like hyperspace or subspace) imports of raw materials becomes viable again. Lastly, fuel may make sense. Think KSP and bringing back karbonite. Sure it takes a lot of the mined fuel to get the extra fuel back, and that's just in the same solar system, but that small amount of extra fuel is way more powerful then "normal" fuel. [Answer] Anything can make sense - it depends on the situation. For example, although Earth as plenty of iron in its crust, you still have to dig it out of there in a reasonably unpleasant manner. If you have a very overpopulated planet and need every inch for agriculture and housing, there's limited scope for creating a huge hole just to dig up iron. The difference between whether you will go for the hole or the planetary transport depends then on the cost. If transporting stuff by bulk is cheap (as in, staff costs are next to nothing, ship costs are a single sunk cost, fuel is cheap once you push it in the right direction etc), then it can be cheaper to mine asteroids and ship the refined material back home. Its the same argument for shipping shoes to the local store - is it cheaper to make them in Vietnam and transport them to your local Walmart rather than make them in a local factory? You bet - otherwise they'd be made in the local factory. For iron this might not be quite so clearcut, but for rare earth minerals the costs can make sense, particularly for minerals that are required in quantity but not available on Earth (think platinum for example). In such a case it might be cheaper to dump a huge amount of asteroid into an automated refinery and by the time it reaches earth, all the rock is chucked away and you have a ship full of refined precious metal. Of course, you then have the problem of having a huge amount of precious stuff that would be cheap if allowed onto the market at once (think diamonds that should be cheap but are currently kept expensive by the traders hoarding them) [Answer] Assuming your universe doesn't enjoy bulk artificial transmutation technology, then rare but useful elements would have to be mined, refined, and transported. The relative abundance of elements, as well as [the cosmogenic processes by which they are created](https://en.wikipedia.org/wiki/Nucleosynthesis), are both well known: [![Nucleosynthetic sources](https://i.stack.imgur.com/KuBbz.png)](https://i.stack.imgur.com/KuBbz.png) No matter where you are in the universe, precious heavy metals are scarce. Our solar system happens to enjoy the relatively rich and diverse effluence of ancient supernovae, but to produce tons of the scarcest metals we have to search for veins and refine megatons of ore. If you're stuck in an interstellar region far from supernova detritus you simply will not find those elements and will have to import them. [Answer] In order to 'make sense' you need to look at the whole universe that they create, not just a small portion. In these universes, they usually have some technology that overcomes the some of the problems of travelling long distances. You already excluded FTL technology in your question, but you need to realize that FTL is a feature of the Alien world, as the nearest System is more than 4 light years from Earth, and they make a multi-system trip in a year or so. These types of technologies distort what 'makes sense' as they greatly reduce the cost if you don't consider that technology. If you look at the development of Canals and Railroads you can see how it might make economical sense to send resources that were gathered from further away rather than those that are closer. There can be similar analogs made for intersystem vs intrasystem travel. Traveling withing a system it difficult and hazardous because of the orbital mechanics of all the interacting bodies. Travelling between systems may be very simple, and cheap, because there is nothing to interfere with you, and once you are at speed, you don't need to spend fuel to maneuver. Inside of a system, you must spend quite a bit of fuel to maneuver and to get your orbits right. You can kind of understand this by looking at travel near a big city. I live 20 miles from my office, which is on the outskirts of a big city. It takes me about 30 minutes to travel to work. There are people that live 6 miles from the office, but in the city, and it takes them the same amount of time, because of traffic, to travel to the office. I could be given a series of tasks in the city that will only have me traveling a few miles but eat up much more time than one would expect, given the distance traveled. Orbiting withing a system is kind of like that, sometimes you have to travel quite far to make a small relative change to your destination. The market is a weird thing, and there is a lot of information encoded in the price. On the micro level, there are plenty of things in our current economy that don't appear to make sense, but they would fully make sense to one who fully understood all the factors involved. Check out this story (<http://www.wsj.com/articles/SB10001424052702303277704579344852685727292>), there is a significant portion of steel being supplied to US producers by China, and India. About as far away as you can get on this earth. There are many economical reasons why this is being done, but you cannot neglect this point. It is really happening. Reality frequently has things that don't make sense on the surface and require further study or pondering to understand. I would avoid building a world where everything is as it would seem it should be. Those types of worlds feel artificial, and readers, viewers, or human batteries plugged into a virtual-reality simulation will reject these types of worlds. Now lets consider their exact situation. Why would someone ship iron ore across several systems when it could be had, in great quantities, in your own system? Because it is cheaper. Why would it be cheaper then? You could gain some answers just by looking at what happens here. Iron mining is unsightly, Strip mining is an efficient method, but leaves surface of the world scarred. Perhaps they are strip mining worlds that are marginally habitable, thus reducing the cost of sustaining a mining crew, but aren't really useful for colonization. Metallic asteroids do seem to be plentiful in our system, but what is the cost of mining them. There are challenges, low G, no atmosphere, no radiation shielding, no ability to grow food onsite, that would make a mining colony on a marginally habitable world more attractive than an asteroid. Another factor to consider is the concentration of resources, depending on the demand, mining a series of asteroids could be much more expensive then setting up a mining base upon a marginally habitable world. [Answer] Goods you can't get locally. In your particular example, it's possible (although unlikely) that the Nostromo was transporting iron ore because there isn't any left in the solar system, so humanity, the bulk of which is still living there, needs to get it from somewhere else. Now the idea that by that point in the future humanity's used up all the iron ore in the solar system (and there's a lot of it) is pretty absurd, although the idea of running out of accessible supplies on Earth is not quite so far-fetched, and certainly there are other commodities which are scarcer which could hit this point. Depending on your interstellar transportation technology of course, you might find that although you do have plentiful iron ore still in your own solar system it's actually easier to get it from another one. Such as, perhaps you have a system based on jump gates, and your local jump gate is conveniently placed for your colony but it's a heck of a long trek to get to the iron ore and for some reason you can't build a gate there as well (maybe you can only have one gate per star for some reason). But there's another system with a gate that's near the iron ore there, and it works out a lot cheaper to use the gates to get to their mines because aside from the gates maybe your propulsion tech isn't much better than our kind of rocketry. Of course, there's an argument as to why you'd have any of these transports having people on board, but that would depend if your setting has computers capable of flying and navigating safely and reliably across interstellar journeys. If you need people on board, the cost presumably goes up a lot as they need life support, living space, entertainment, salaries and the ship has to not accelerate at a rate that turns them into a pulp. But the only reason anybody ever ships anything anywhere is because it turns out to be profitable to do so. That's not likely to change in an interstellar society, you just need to figure out why it's profitable. [Answer] Drugs legal or otherwise. Delicate biological goods which are impossible to cultivate away from their home ecosystems. People with specific training or skills. Goods which require lots of labor. (Shipped from where labor is cheap to where labor is expensive) Manufactured goods that one group has perfected and nobody else can quite get right. (Swiss watches a century ago, Italian sports cars today) Manufactured goods or raw materials the production of which causes pollution which the buyers would like to externalize to other cultures. (Rare earth minerals from china) High tech goods shipped from higher tech cultures to lower tech cultures. [Answer] We can take some lessons from modern trade here too, that I think are too often left out of this conversation. The original idea of what one country would export versus import came down to comparative advantage - it's covered in any intro-level undergraduate macroeconomics course. Simple models went something like: I have cheaper labor and you have cheaper capital, so I produce more labor-intensive goods and you produce more capital-intensive goods, and we trade. Huge problem though - the real world obviously doesn't work this way. The US had cars from the US... and cars from Germany, and from Italy, Japan, Korea, and so on. Why in the world do we do that? I won't delve into the economics too much, but one of the early solutions came down to the love of variety. This was, incidentally, the area Paul Krugman's work won a Nobel in. We don't want just our cars, we want your cars too. So people in one solar system might pine for the finished goods from another solar system, just because they want exotic variety. But, is this feasible over interstellar distances? I think it's easy to get hung up on "nope" based on what we know now. But personally I think if people in the future are still what we would recognize as "people" that they'll be finding a way to ship this stuff, at least for those wealthy enough to afford it. [Answer] Think about it...you have a freighter, that has FTL capabilities, and you want to make a lot of money. Depending on how FTL works in your world, is a smaller or larger ship more efficient, or is size not a factor (I think this would be more likely the case). Ship size would really only affect a ships sub-light maneuvering capabilities. Additionally, ships will have some sort of nuclear reactors or something similar to minimize the fuel requirements and have as few crew members as possible. So assuming you have a ship already in space, not requiring much in the way of supplies or fuel, with FTL capabilites, why wouldn't it be as large a ship as possible, completely dedicated to ripping apart rocks, planets, etc., in order to maximize the profit from each trip;i.e an FTL capable Nostromo. This makes jump costs known and any freight charge, for any freight, that exceeds that cost is profit. So basically, anything you can make a profit on qualifies as "worth it". [Answer] # Water ice If you are going to colonize planets, you will need lots of water, and apparently water is not so common around the solar system. # Gases, or other elements only available in trace amounts. Gases only found in trace amounts in Earth's close neighborhood could be extremely valuable. NASA already has plans to harvest Helium-3 from a moon base in the future. Given the appropriate technology, a near-endless source could be extracted from gas giants around the galaxy. [Answer] Just going to take this a few directions that I haven't seen yet: The beings importing the goods are completely out of the goods otherwise This is a sidestep to "X is unique". Maybe Iron was plentiful, but it all got used up. The populace in question has resorted to recycling, but they still need an infusion of pure Iron due to imperfect recovery. Asteroid mining makes up the difference. Moving around space is ridiculously easy If solar sails make fuel costs cheap, and robots do all the hard stuff, why not? Which leads into: Automation is cheap enough, and the item is non-perishable If you have robots, who do not sleep, or get bored, or age flying the ships, and the item doesn't go bad, why not? Once you get a bunch going, you will have this chain of income coming in after a long initial wait. The product in question is incredibly important, and any ends justify the need See: Space 2001, The Omega Men comic series, (maybe) Avatar, and any other work of fiction where unobtanium prevents some catastrophic event from happening. In which information is the product, and the density of information is not transmittable There is a saying in IT that a honda full of hard-drives barrelling down the highway has much more bandwidth than broadband. What would you do if you found what amounted to the alien Library of Congress, with incredibly dense DNA encoded information in reams of shelves of buildings of information? It would take forever to beam it with radio waves, it's lossy, and there is no fiber-optics in space. Chances are, the best way to get the info to whoever needs it is to ship it to them, or ship them to it. Tourism I'm not saying that tourist would be shipped this way, but if there are colonies that are also tourist destinations, they will likely need regular and large supply drops. Tourism has supported dictatorships and countries that ordinarily have nothing to export; don't disregard human curiosity. [Answer] Your thinking is limited by our current knowledge. If we use the logic presented then the same can be applied to our recent history. (And current market economics) Any goods that are abundant in the new planet but can't be found on earth will become high value and can be transported. Our history shows that raw materials will be shipped in quantity (Think cotton, spices etc in the past) and manufactured here. This supposes that we will find materials in space of high value to us, (superconductors etc) which are not available on earth or the solar system. [Answer] Seeds, and other biological derivatives. Minerals and ores are likely to be found anywhere, mined off of other planets or asteroids or the like - and perhaps elements to make up whatever alloys or compounds are needed for manufacturing, or living. After all, elements from the periodic table are unlikely to change if they're found on an asteroid or a new planet. However, biological elements are probably going to continue to be a limiting factor. The places they can be obtained are limited, dependent on a lot of other limiting factors, and they will be in high demand (because they're limited) and thus quite valuable. So, people want (for example) bread. Wheat bread, finely ground white flour bread. They might not be willing to pay the prices for loaves of bread to be shipped, unless they're really, really rich, and even bags of flour or grain are likely to be too expensive, too much spoilage in transit, to be economic to ship around - but some corporation or other ships wheat seeds, and sets up a farm/hydroponics/whatever, and starts growing wheat to be processed locally, and the price per loaf drops to something hefty but not unreasonable, because people would want that constancy of foods from home, or exoticism of foods discovered from other planets. Or their familiar vegetables and pantry staples. And herbs and spices are a whole new level of good tradables - they would be in very high demand (a small amount brings familiar flavors), and pretty low bulk - either as seeds or finished products. It's one of the reasons spices were so prized for trade goods historically - when this situation was more or less fact, each civilization was self sufficient and travel was long, costly, and unreliable - so luxury goods were shipped, not so much raw materials. Beyond foodstuffs, many plants are used for other things - cloth or fiber (cotton, linen, hemp), dyes, medicines, drugs (both medicinal and recreational) the many uses of plant matter (paper, wood for fuel or building, cardboard, charcoal), chemicals used in manufacturing processes or plants used for environmental effects (ornamental, or to crowd out other plants, or to provide some resource). Sending the finished products might be possible, depending on supply, demand, and price - but sending the means for each colony to make their own independently (seeds, manufacturing tools and equipment, etc) would likely be cost-efficient and sustainable enough to make it economic to ship initial loads, replacements for crop failures, occasional followup loads of seeds to increase diversity, and so on. So it need not be a one-time cargo, either. Many of the products people use interfere with the plant's reproduction (wheat that goes to bread does not go to the next wheat crop, many vegetables are picked and consumed before the seeds finish maturing). Even with a concerted effort to make the populations of plants on each world self-propagating, periodic infusions of new diversity from fresh seeds, or replacing generations lost after crop failures, would probably be quite welcome and very valuable in their own right. A load of mixed seeds would be pretty valuable, in high demand, and still give enough yield for the space they take for the end results to be valuable but not out of reach for people to actually buy. Even if the long shipping, imperfect storage, etc leads to some amount of loss or spoilage, some seeds would be unexpectedly valuable (from crop failures, or a newly discovered use) to make up for it. Animals and their products would also be in high demand. Again, shipping adults would likely be too much expense for too little return, too much lost in transit, too messy. Only the really rich could afford such. But shipping genetic material for cloning, or for in-vitro fertilization, might make the end products reasonably profitable. Somebody pays the really high price for a ships-load silk from earth, somebody pays the same price for carefully preserved silkworm eggs (or spiders eggs, for spider silk instead) - and the silk they produce locally is a very popular and more affordable luxury item. So the local herds (sheep, cows, horses, the whatever from colony x and the whatsits from colony 3a) might have to be shipped over for high prices and lots of loss to begin with, depending on the tech levels involved (though maybe even cloned beasts might be enough to start a herd, if only to the second generation), but they could be supplemented with new genetic material from in-vitro fertilization within a reasonable level of technology. Manufacturing equipment is probably also going to be popular - raw materials can be found, sure, but tools (and further back, the tools to make the tools) are going to be something that's a lot easier and cheaper for a central, specialized manufacturing place to make in bulk than individual colonies. The price for making everything themselves from scratch is effort, especially when a colony is just starting out and having to do everything for themselves. The price of shipping would offset by the production capability, the further back along the process you go - so a shipment of tractors, gets paid for in how much more can be produced with them than without them doing everything by hand - the pieces to make a tractor factory, gets paid out in every tractor and everything every tractor made can produce. The less that can be shipped, and the greater its impact, the more likely it would be cost-effective. And, there would be a continuing trade in repair parts and upgrades. It might take a while for the colony to be able to product enough of their own whatevers to pay off the equipment (with a colony credit line, or 'company store' levels of human plotting) - but for the colony to exist, they had to think something was there worth investing in, yah? And they're going to be paying off the shipping cost with stuff they think will be worth it - ten years' (or whatever) cost for shipping, but it would take fifty years without it - so forty years to make up the difference in the price. [Answer] I suggest something smaller, and infinitely Lighter. The distances and times needed for these transactions provide for an ever growing difference between Homeworld and colonies, each trip spanning generations, more or less. I suggest that Ideas - sheer human (or other) ingenuity would be the ideal cargo. Why carry a cargo hold of weapons when just the blueprints and theory would do? Trade for the colonies' latest gizmos and potions, but only the Idea of them. The commerce of intellectual property is abundant on Earth now, Imagine if your systems diverged as expected, a network of idea trading could be economical to run, and profitable to each world. [Answer] What different about different solar systems? The are going to have different laws. Different laws about what can be done with intellectual property. Different laws about what kind of GMO organisms they allow. Different laws about whether or not technology that produces a lot of radiation is allowed. The legal tension of a product that was produced in galaxy A by an organism that isn't legal in galaxy B, could make for an interesting plot. New colonies with low populations can profit a lot from having high value items that can only be effectively produced at scale to them. A classic example are computer chips. [Answer] > > Scarcity (also called paucity) is the fundamental economic problem of having seemingly unlimited human wants in a world of limited resources. It states that society has insufficient productive resources to fulfill all human wants and needs. > > > The notion of scarcity is that there is never enough (of something) to satisfy all conceivable human wants, even at advanced states of human technology. Scarcity involves making a sacrifice—giving something up, or making a tradeoff—in order to obtain more of the scarce resource that is wanted. (<https://en.wikipedia.org/wiki/Scarcity>) > > > There are plenty of cases for large-scale transport of resources between systems, even if those resources are readily available locally. Since utilization of a resource has opportunity cost associated with it, society will tend to allocate resources (over time) to whatever production it feels is most desirable. A good example of this is the current trend of farmers parceling off their acreage to sell to homebuilders and developers, since the land is more valuable for housing than it is for crop and livestock production in populated areas. Consider this... lets say that Earth is the galactic seat of our intergalactic society and also boasts as the origin of our species. It has a huge population, making land extremely scarce. It becomes a city-planet covered in high-rise ultra-luxury housing, and living on Earth is considered very prestigious. The price of real estate skyrockets, and eventually only the wealthy and influential can afford to live on Earth. High property values and associated taxes drive even the middle-class out to neighboring settlements, where they become impoverished due to lack of opportunity. Resources we take for granted have now become expensive and difficult to obtain, and mining companies find it more profitable to sell their land for windfall profits under pressure from increased environmental regulation, "not in my backyard" policies, and exorbitant labor costs. Those production facilities left are under massive demand, and the price of commodities are driven through the stratosphere (literally). Some industrious firm then finds it profitable to mine nearby planets and asteroids for those resources, and for a time, also starts reaping huge profits from the venture by selling (comparatively) cheap ore back on Earth. The Earth mining companies, flush with cash due to lack of competition and high demand, start buying mining rights to nearby space objects to protect their oligopoly. Now you have a scenario where, while the resources themselves are abundant, they are otherwise allocated. At the same time, large-scale building projects have slowed due to the considerable political red-tape and overcrowding situations, where every single construction project requires displacing existing residents and having designs approved for both engineering and aesthetic purposes, requiring multiple rounds of revisions from fickle political organizations before demolition and groundbreaking can occur. Projects stretch out a decade or more, with many of the resources being sourced elsewhere (construction workers or robot maintenance techs can't afford to live on Earth). Johnny Entrepreneur (maybe a former high-level mining company employee with a lot of knowledge and a lot more contacts) says, "Hey, I've got a cheap off-world labor source and access to all the steel you need. Sign a contract with me, give me 50,000,000 credits, and I'll guarantee on-time shipments at a great price starting in 7 years when you are ready to start building. If you don't want my steel, I can always sell it to your competitor." The builder, with his source of cheap materials, now has a competitive advantage and starts outbidding his competitors one after another. Those competitors in turn start sourcing their materials that way too, creating a demand for extraterrestrial steel imports. Meanwhile, Johnny Entrepreneur uses a small part of his contract advance to purchase some derelict military vessel from a defunct establishment, retrofits it to carry cargo, and rounds up some desperate and impoverished former Earth residents, offering them free land on some distant planet, provides for the immediate needs of them, their spouses, and children, and the employees get the promise of a big paycheck when the contract is fulfilled. The terrestrial mining companies, now facing a much cheaper source of supply, find it more profitable to finally sell the remaining mines to developers, and just like that, steel (or more accurately, iron ore), becomes one of the scarcest resources on Earth despite the fact that it is one of the most abundant things on the planet. The terrestrial mining companies' war chests are opened to develop and build the biggest, most efficient ore freighters in the galaxy so they can supplant the comparatively small start-up mining companies, and several years later the Nostromo leaves space dock. Anything... absolutely anything will be transported across distances provided that someone can make a small profit off of producing and transporting it, and it can be delivered within acceptable timeframes. If you don't believe me, take a look at the current industry for transporting things like hay long distances, when it can be readily grown locally. Paying 5,000 monetary units for a truckload of hay makes a lot of sense when that same 10 acres can support 30,000 monetary unites worth of horses, or it can be sold to a real-estate developer for 25,000 monetary units per acre. Iron ore would be no different in a galactic society where land on Earth is at a massive premium. [Answer] Lots of good answers here and I won't repeat them, but one thing everyone has missed - putting the incentive on export rather than import. Or to put it another way -- is there anything that you'd be so desperate to get out of your neighborhood that you'd be willing to physically export it to another star system? Consider toxic waste. If society is generating something toxic enough, they might find that the only way of disposing it would be to put it on a ship an send it as far away as possible. [Answer] High tech items that only advanced civilizations can produce such as: 1. Advanced materials such as carbon nanotubes and exotic isotopes 2. Nanobots 3. Advanced weapons (lasers, force shields etc) 4. Advanced manufactured goods - antigrav engines, teleportation devices, advanced computer technology, FTL drives 5. Medical technology 6. Exotic foods, art, and luxury goods that the members of the advanced civilizations can amuse themselves with. ]
[Question] [ Setup: Earth, current day. US president decides to attack fictional country of Lalalistan, because terrorism/drugs/whatever. This attack has big support in NATO countries and Russia with China officialy object the attack, but remain neutral. (Example: Lybia attack). So, while it is officially NATO action, it is mainly driven by US Army. The twist The dictator of Lalalistan sealed a deal with the devil and obtained Death Note and Name vision === For those who do not know how Death note works: === If you know Anime series [Death Note](https://en.wikipedia.org/wiki/Death_Note), you can skip this section, because the dictator of Lalalistan obtained exact Death Note as used in this Anime series. So for these who do not know how the Death Note works: * Death Note is magical artifact in form of usual paper notebook * The human whose name is written in this note shall die. * This note will not take effect unless the writer has the person's face in their mind when writing his/her name. Therefore, people sharing the same name will not be affected. * If the cause of death is written within the next 40 seconds of writing the person's name, it will happen. * If the cause of death is implausible, or not specified, the person will simply die of a heart attack. * After writing the cause of death, details of the death should be written in the next 6 minutes and 40 seconds. [Source](http://deathnote.wikia.com/wiki/Rules_of_the_Death_Note) The Name Vision works simply: If you look at a person (even through video recording), you can see their real name and therefore write it into the Death Note correctly. === End of Death Note mechanics explanation === Lets give the country of Lalalistan shape: The Libya example could work well: Lalalistan is about as big as Libya and has military force of Libya a year before NATO attack. However, it differs from Libya in two details: First, the people of Lalalistan support their dictator and think that the NATO attack is act of aggression and second, I doubt that the fine people of Libya ever dealt with a devil. The question: Could the US military with joint help of other NATO countries sucessfully attack this country without using nuclear weapons? Also, bear in mind, that the Death Note is only one example in this world and the artifact works even if you tear the pages to small pieces. To add more details: If only names should be written into the notebook, and someone clever would be using the notebook, you could fit in 250,000 names. The dictator is not that clever, so lets give him capacity of 100,000 names before the Death Note is fully used. [Answer] In order for the dictator to remain in power he will have to keep his powers secret (this is *vital), while strategically eliminating foes in the international political arena. Your Situation* The US has decided to attack. This is bad, however it is NATO that is backing the US's access to your country. The US is bound to have political opposition in NATO who would be able to vote against the invasion, you just need to nudge them into action. If you simply start executing politicians left, right, and center you'll paint a target a mile wide on your back. You want to create an image of being a victim, not as a dangerous maniac with magical assassination abilities. Tipping the Scales Any US invasion is going to face both international and homegrown opposition. You could start by assassinating a few key US politicians, and loosening the President's grip on the opposition in Congress/the Capitol. Remember that you can't just kill the President and end the war. The US military is a machine that cannot be stopped simply by cutting off its head. They must be ordered off the attack. Your army must be ready to hold the US off for as long as possible. During this time you must contact the leaders of China, and Russia. Kill one of their powerful enemies and tell them that you have "agents" in place that can solve their problems, in exchange for a little political help. In the mean time destabilize the governments backing American foreign policy. Cause the "accidental", and very public deaths of the leaders of Germany, France, etc. In order to make their deaths appear accidental you could try killing them while they are all attending an event together, and dictate that they die in a fire, etc. With so many NATO states in turmoil the US is going to find the political landscape shifting beneath their feet. Now would be a good time to assassinate the president, maybe by having him commit suicide in a very public way. Can death note also make the victim say some words before they die? "This invasion was a mistake, I am so sorry" would be a good little script before blowing his own brains out in front of a room full of journalists, for example. You can come out of this smelling like roses, all while redefining international politics, and changing the political landscape to suit your needs. Additional Info As I mentioned, your military forces are going to have to oppose the US army/navy/air force for a little while. This time might be as short as a day, or as long as a few weeks. You can use your assassination abilities to seriously screw with the American war effort. For example, it is relatively common knowledge which military leaders are in charge of the invasion, or which admirals are running the show off of which carrier. Heck, this information is even provided in the news sometimes. It's also quite easy to find pictures of these officers on naval websites, on books they have published or been the subject of, etc. So here's an idea: > > *Kill the admiral commanding the attack fleet by having him detonate a ship-board nuclear device.* (or some other powerful bomb in one of the ship's ammo bunkers) > > > Now *that* is going to put a crimp in the US's invasion plan, and buy you some time to bring down the political alliance against you. In response to the tragic accident that the US fleet has suffered you can then initiate talks for a temporary cease fire in order to allow the American fleet to care for their wounded. If you are seen as a reasonable and compassionate person you will receive a lot more support from the international community. You will also have complete and utter deniability as far as how the attack took place, as your country clearly doesn't have the capabilities to attack the US Navy on that scale. Warning Revealing your abilities to *anyone* will cause the world to come crashing down on you. You will become the most hunted man to ever have lived. Keep it a secret. [Answer] The thing is, the United States also has that ability. It's called an "[MQ-1 Predator Drone](https://en.wikipedia.org/wiki/General_Atomics_MQ-1_Predator)" and it is an unmanned aerial vehicle which flies at a high altitude and fires hellfire rockets at a ground target. The United States frequently uses this technology to assassinate people it suspects of being involved in terrorism. Threatening to magically kill a large number of US citizens by death note definitely fulfills the definition of a terrorist threat, so the precedent is there. All they need to know is the current location of the president and they can assassinate him with a drone strike. [Answer] No. You can't attack them. The Dictator would simply start killing world leaders or famous people until the attackers went away. It's the ultimate MAD. However there would then be an intensive program to work out just where the Death Note is stored and steal it or hit it with a nuke. A single deterrent is not effective long term as it can be neutralized and then you have no backup. [Answer] There are two lessons here learned from Iraq. First: finding the leader of a country isn't easy. Secondly, Even after you take out a country's leadership, you are still a long, LONG way away from seizing/securing the country. You actually have to eliminate everyone willing to take up arms against you. On the other hand, all you have to do to defend your country is have people still fighting when the other side gives up or is unable to continue fighting. So at the absolute guarantee of going on every watch list on the planet here's what you write: * Barack Obama - Nuclear blast @ the White house. * Joe Biden - Nuclear blast @ the pentagon. * Robert J. Bentley - Governor Alabama - Nuclear blast @ the Alabamian capitol building. * Bill Walker - Governor Alaska - Nuclear blast @ the Alaskan capitol building.. * *etc* And you continue for the rest of the states. By waiting longer than the needed 6 seconds after each kill, you can ensure that each death is its own explosion. With a mushroom cloud at the capitol building in each state, the country will not be able to continue their war. Even if they did have the capacity to continue the fight, they will be far more interested in getting home and fixing things there than the drugs or terrorism. If you don't think that will make the army go home (maybe they'll think you had some sort of part to play in the nuking and want revenge) have the US ambassador to Russia and China assassinate those country's leaders instead of dropping nukes. They'll be too busy fighting off super powers to mess with Lalalistan. An agglomeration of these two methods could be really evil. "Barack Obama - Russian nuclear blast @ the White house" All the advantages of both scenarios. If you have a problem with the collateral damage, just aim for the leadership of the government and military. It probably wouldn't be as effective, but your power advantage over the US attacking you is so vast, I don't know if it would matter. [Answer] Yes, taking over this country is entirely possible. How? ## Assasination I'm fairly sure every single intelligence agency and military force of the world would be interested in getting control of the Death Note, or at least would want this president to no longer be in control of it. Quite apart from that the larger criminal organizations and many warlords would also try to get control. If it was discovered who exactly had these powers and how they worked the person would make it to the top of the priority-to-kill-list of the CIA easily and instantly. Taking him out should be a fairly easy task, as he has no special magical powers of any kind protecting him. Depending on how clever the dictator and his people are he might die within a week from a drone strike, or maybe in a car bombing after a couple of years... But I'm certain that his fate is sealed them moment his powers get publicly known. Obviously these operations would be covert as to not give the dictator any target to retaliate against should some of them fail. [Answer] You've just developed a new form of international stalemate: ## Mutually Assured Assassination If you attack our country we'll assassinate your entire leadership. All of whose names and faces are publicly known. While the country could be attacked, you're going to lose a lot of people who consider themselves to be important. Presidents, Defence Secretaries, Queens, Prime Ministers etc. If you feel the almost guaranteed loss of these people is worth the risk, then yes, sure you could invade. However should any of these people die unexpectedly in mysterious circumstances the leader of Lalalistan will be prime suspect and probably wouldn't survive the week. --- Can the deathnote mechanics be abused? Is it possible to write that someone dies in bed at a grand old age after a happy retirement surrounded by great-grandchildren? [Answer] Death Note has a weakness. It cannot be used to control any others except the to-die. Any attempt to do so results in the method used switching to [induced] heart attack. If the target cannot be killed by heart attack due to not possessing a heart (this already exists) it does not die. Kind of expensive, but if we can keep our leaders alive we can press the attack by any means necessary. Death note is not very powerful against an APC operated by an unknown individual. [Answer] The United States probably wouldn't be able to effectively fight this guy. He could relatively easily assassinate every high-ranking government and military official and have `>=` ~20,000 names to spare. As a matter of fact, as soon as the first US troops enter his petty kingdom, I expect him to be busily copying names from the [order of presidential succession](http://www.infoplease.com/ipa/A0101032.html) and googling videos of them speaking/having his minions bring him physical copies of said videos. That is why you make the dictator think you will do what he says. The chances are high that he will demand the US(NATO) withdraw from Lalalistan immediately. He will probably execute a high-ranking US official/general(probably the president) to provide of his power. Have the US make a big show of pulling out - load gear onto ships/mass forced-marches out of the country. Once Evil Dictator Dude sees this, he will believe he has won. He will put his guard down some. Then have the US send a SEAL team to assassinate him. They succeed, his country collapses into a million warring factions, and the US has control of the Death Note. Now Mr. FormerVicePresidentCurrentPresident can go back to pretending to furiously hunt for the terrorists/drug dealers/crooks while taking bribes from Big Tobacco to not make tobacco illegal. [Answer] You forgot to mention a critical feature of the Death Note as shown in the anime. You can control the actions of the victim. Lalalistan can use this to get confidential information. If they work very aggressive with the Death Note they can obtain the names of every high ranking officer within hours, causing their command structure to collapse or simply change the orders. The US and their allies would even lose the ability to lunch their own nukes. So no, the US has no chance against a country with a death note. [Answer] This is classic MAD, so we need to think about disarming strikes. Short answer: NATO has got good odds. A disarming strike is a power surprise attack that destroys the enemy's ability to counter attack effectively. This is normally nuking all the enemy's nukes. In this case is either destroying the note (breaking it into such small pieces that you can't fit a single name in it) or killing enough aviators to disable the NATO air force. How fast can one the book kill? The average person writes around 20 words per minute. Assuming you have to write the first and last name, that is 10 kills per minute or 1 kill every six seconds. The US has over 3600 combat air craft; let's assume the rest of NATO has the same amount for a total of 7200 planes and assume 2 pilots per plane. Assuming the writer knows all the pilots names, he will need $\frac{7200 \cdot 2 \cdot 6}{60 \cdot 60}~\text{h} = 24~\text{h}$ to wipe out the air force. Assuming he does not run out of space on the paper. On the other hand, the air forces only needs 1 bomb in the right place and they have easily 7200 tries. So if the location of note is ever discovered, they can pounce and win. I like their odds, BTW it’s hard to see a plane incoming and you get a few seconds of warning so I don’t think the note book writer will get many kills. What if we divide the note? The question states the notebook still works if sheets are torn out. So a wise user will divide the note among many users across hundreds of users to make it hard to destroy and so prevent a “perfect disarming strike”. In the event of war, this also increases the notes kill rate by a factor of a hundred. This makes it possible to still drop many enemies and to make the invasion very costly. [Answer] ## Deny them knowledge Off your head, how many politicians and military leaders can you name of a major country that is not yours? If your first step is to disconnect them from all communications networks and isolate them from other media, then Obama and a bunch of other top public personae are vulnerable, but all the people and officers actually planning and implementing an attack are effectively anonymous in the absence of intelligence leaks. They could continue the invasion even (or especially so) after assassination of the first line of political leaders, while not being vulnerable themselves. Furthermore, normal combat would not be affected - Name Vision applies when seeing a particular person, but much modern warfare is conducted beyond visual range or in vehicles. And that assumes that the president is willing to be on the front lines - which would end everything after a sniper from cover, artillery shot or a bomb from some aircraft. In pure military means, a person with such a death note would be similar to an extremely good sharpshooter but not much more, and also have most of the same limitations - they must notice the enemy first in order to do damage, and are vulnerable to vehicles, all kinds of indirect fire and close range combat/ambushes. [Answer] The deathnote could be easily defeated. Just write a computer program to generate names consisting of a few million characters and makes the names official. Now one name will physically not fit in the notebook, rendering the notebook useless. If the notebook magically scales to the size of an average name, etc. It would still take thousands of years to write a name. Basically, human manual input is the weak point. [Answer] As mentioned already, use Death Note ability to command what person should do in the minutes leading to his death to not only kill, but to give enemy leaders bad image in the process. Make president go ballistic, grab a security's automatic pistol and open fire on peaceful anti-Lalalistan war demonstration and be killed in process. If we call back to anime already, think Code Geass' Yuffienator case. Make top generals announce their heinious plans on TV to bomb "those Lalalistan untermensh" with new ultra-toxic-checmical-bio-bomb to "preserve only lives that matter - our soldiers", then to personally press big red button in bombing facility only for it to blow up spectacullary and kill generals in process (it is not necessary for them to actually develop such weapon - only to announce and blow themselves up in some imposing-looking lab, so that should be plausible by DN rules). Plan about 10 performances like that and general chaos of forces left without command and backlash from other nations should be enough to make US busy with its own affairs instead of invading Lalalistan. [Answer] No, the USA does not stand a chance. The death note can easily kill people it doesn't know the name of. Even keeping to plausible scenarios, we can use the 7 minutes and 20 seconds of description of how someone died to write a single name and cause dozens, thousands, millions or billions of deaths as required. For 20 years, the US nuclear launch code was 00000000000. <http://www.dailymail.co.uk/news/article-2515598/Launch-code-US-nuclear-weapons-easy-00000000.html> Even after they were changed to something more secure, Jimmy Carter left them in his suit pocket when it went to be dry cleaned. 2 of the 3 required officers on a Russian Nuclear Submarine voted to launch their nuclear missiles when an American destroyer launched 'practice rounds' at them. If the 3rd had agreed, the missiles would have launched. With the USA and Russia both at war in Syria (and not exactly on the same side), we have seen some incidents recently that could have escalated. As recently as 1995, Russian early warning systems detecting a nuclear launch (actually a weather balloon). While a nuclear war is far from probable, it is certainly plausible. Pick a single person living in a mid sized US city, and write the note that he died "In the Russian nuclear retaliatory strike". Originally this post involved a person spontaneously travelling back in time and exploding with force sufficient to destroy the continent of the USA. This was before the Question specified that implausible deaths will just result in heart attack. [Answer] Unless the word implausible in the description of the Death Note means what it means when I use the word, the US has no chance at all. As the Death Note and Name Vision are described, the dictator of Lalalistan has infinite wishes, limited only by requirement that he must envision a specific person for each wish, who then dies. So the dictator simply envisions a random public figure from America, and writes "X sends out a mental blast which kills every other American, and then dies from the stress." If the term implausible is meant to exclude that, then the specific meaning of implausible in this context needs to be expressly spelled out. ]
[Question] [ Daddy Longlegs Spiders, officially "Pholcidae" are known to be the worlds most venomous spiders, sort of. We are supposedly unaffected by them because their fangs are too small, the shape of their fangs, or their venom doesn't affect us due to size. > > According to Rick Vetter of the University of California at Riverside, the daddy long-legs spider has never harmed a human and there is no evidence that they are dangerous to humans. - <https://en.wikipedia.org/wiki/Pholcidae> > > > I would like to know how large one of these friendly but venomous spiders would need to be to cause significant harm/damage or even death to an average sized human. I'm creating something along the lines of the movie Eight Legged Freaks (2002) Any information or speculation is appreciated! [Answer] As noted in the comments, the Wikipedia article you cited contains a description of a Mythbusters episode in which Adam Savage allowed himself to be bitten by a daddy-long-legs. He experienced a "mild, short-lived burning sensation." From this we can conclude that pholcidae can bite humans, but their venom is not toxic to us. While the venom of pholcidae has [never been specifically studied](https://www.livescience.com/33625-daddy-longlegs-spiders-poisonous.html), we can extrapolate some things from the study of other spider venom. Venom is [characterized into two categories](https://www.compoundchem.com/2015/05/21/spider-venom/); necrotic and neurotoxic. Because Mr. Savage did not experience any ill effects to his nervous system, like the paralysis that often results from the bite of the black widow, we can assume that pholcidae venom is not neurotoxic, at least to humans. So, it's necrotic. This means that the main active components are peptides, and the main purpose of the venom is to aid the external digestion of the spider. This lines up with what we know about the hunting behavior of pholcidae; they immobilize their prey with silk-like threads and then envenom and consume them. It also lines up with Mr. Savage's experience; a mild burning sensation is consistent with being partially, mildly digested. It was a very small amount, so his body was able to very quickly recover from the damage. This has lots of potential in a horror scenario. Victims do not die instantly of a poisonous bite; they are entombed in silk and then injected with acid that burns them alive very, very slowly, while a giant spider takes small bites out of the burned bits. That's terrifying. You just need to make the pholcids large enough that their webs could catch and hold a person. Pholcids are known to hunt huntsman spiders, which are roughly the same size as they are. So, your pholcids should be roughly person-sized. [Answer] While the question may suggest that it's looking for an answer involving the spider's venom, there is no such specification directly asked for. As such I challenge that a spider need only be large enough to choke on to cause death. Perhaps these spiders of yours are prone to hunting slugs that like to dwell in shallow caves and confuse the human tongue for their prey and in the process of trying to hunt it wind up suffocating the unfortunate persons. [Answer] As their venom would be useless against humans, the only ways such a creature could harm us would be if they were large enough that they could either crush a human being or their mandibles were large enough they can kill through the sheer force of their bite. Each would require the spider to have a body at least the size of a human's, probably much larger. At that size, its legs however would be unable to support the weight of the body unless you change the physiology of the spider to have legs that are far thicker and more muscular, which would potentially give it another way to inflict harm: striking with one of those legs. With a total size for the creature maybe 4-5 times that of the body, you'd have a spider with a body 2 meters long and half a meter wide, with legs up to 5 meters long each. At that size, it wouldn't need to bite or crush most people, they'd die of a heart attack just seeing one coming at them through fear :) [Answer] This is a bit of a weird question. In North America we have two spiders that have medically significant venom - the Black Widow and the Brown Recluse. They are both small spiders, but rarely lethal. In fact, for most health youth and adults a bit from a Black Widow is only incredibly painful. The mechanism by which it causes death is actually because it causes paralysis, typically the diaphragm, causing suffocation. I'm not aware of a brown recluse bite ever being responsible for a death, and they are also the most misdiagnosed spider bite. All of that is background information - either your killer pholcid spider (not to be confused with a harvestman, which is an arachnid but not a spider) is going to require a different venom, or it's going to need to go through some pretty radical changes. We know that their venom is not particularly potent. Unless you have some sort of severe allergy, you might get a mild burning and some redness in the extremely unlikely case of actually getting bitten. So if we rule out any changes to venom (aside from perhaps the amount produced, due to size changes), we've basically just got to go with sheer size. If you've hung around worldbuilding for long you'll know that the square cube law comes into play a lot when we're scaling stuff up. I don't know if the numbers could even pan out, but basically what we're looking for is going to be fang size. According to that Wikipedia article, their fangs are 0.25mm in length. Let's say we need their fangs to be 100 (about 4") long, based on the typical legal knife-length limit. That's 400x the size. That means that their 10mm body will be 4,000 - or about 160 inches, or 13 feet. Their legs will be 20,000mm long, or 65 feet. That's just ridiculous. At that point they're probably able to cut you with the claws on their feet more effectively than using their fangs. This says nothing else about the physiological changes they're going to need - their book lungs will no longer be effective, their hydraulic blood system will be problematic... in general, they're going to have a lot of problems, even if you can handwave that way. Although on the plus side, they will definitely be large enough to kill an average human. [Answer] > > Daddy Longlegs Spiders, officially "Pholcidae" are known to be the > worlds most venomous spiders, sort of. > > > We are supposedly unaffected by them because their fangs are too > small, the shape of their fangs, or their venom doesn't affect us due > to size. > > > According to the very same WP page you linked in the question, in fact the two paragraphs around the one quoted in the question, [that is a myth](https://en.wikipedia.org/wiki/Pholcidae#Misconceptions): > > There is a legend that daddy long-legs spiders have the most potent > venom of any spider, but that their fangs are either too small or too > weak to puncture human skin; the same legend is also repeated of the > harvestman and crane fly, also known as "daddy long-legs" in some > regions. Indeed, pholcid spiders do have a short fang structure > (called uncate due to its "hooked" shape). Brown recluse spiders also > have uncate fang structure, but are able to deliver medically > significant bites. > > > (paragraph quoted in question removed) > > The legend may result from the fact that the daddy long-legs spider > preys upon deadly venomous spiders, such as the redback, a member of > the black widow genus Latrodectus. To the extent that such > entomological information was known to the general public, it was > perhaps thought that if the daddy long-legs spider could kill a spider > capable of delivering fatal bites to humans, then it must be more > venomous, and the uncate fangs were regarded as prohibiting it from > killing people. In reality, it is able to cast lengths of silk onto > its prey, incapacitating them from a safe distance. > > > As for how big such a spider would have to get, assuming it keeps to its same predation behavior, it appears it would need to get big enough to kill the human with a normal (non-envenomed) bite: > > The web of pholcids has no adhesive properties and instead relies on > its irregular structure to trap prey. When pholcid spiders detect prey > within their webs the spiders quickly envelop prey with silk-like > material before inflicting a fatal bite. The prey may be eaten > immediately or stored for later. > > > Wolves have been known to kill humans with neck bites. One would imagine a significantly smaller animal could pull off the same trick with an incapacitated human, (which is where the projected silk comes in). So the limiting factor is likely to be some combination of ability to produce enough silk to disable a human-sized creature, and mandible size. [Answer] The size of a Brazilian Wandering Spider, if a mutation occurs in a species of Pholcidae so that it creates a cytotoxin venom instead of a necrotic venom. ]
[Question] [ The eleven year old son of the king and queen, prince Jeoffrey Boratheon, is destined to take the french iron throne after his father passes. One night, an old hag knocks on the castle door and begs to spend the night, to which the prince answers the door and refuses. However, this was a test, as the hag takes her true form as a beautiful witch. After the witch murders his parents, the witch declares that Jeoffrey has no love or kindness in his heart, and decides to punish him. She curses him with the form of a hideous beast, and transforms his household (servants, maids, staff, etc) into sentient objects that spontaneously burst into song at inopportune moments. The witch declares that this spell can only be broken by the true love of a woman, which must happen before his 21st birthday, or the spell would be made permanent. The witch believes that this would teach him a valuable lesson in decency and humility to prevent him from becoming a murderous psychopath. It soon becomes apparent that finding true love is the least of Jeoffrey's problems, as the country still needs to be led. Taxes need to be collected, court needs to be held, land needs to be defended from barbarians, etc. On top of that, there are many who would seek to take advantage of the situation and overthrow Jeoffrey. The duties of a traditional monarchy must still be conducted. Being turned into a monster poses serious obstacles. If the people discover what has become of him, out come the torches and pitchforks. This kingdom must still be led and controlled by the prince while keeping his situation a secret from the public, long enough for him to find true love. How can I make this happen? [Answer] # The Appeal As the witch sought to leave, a brave young pushbroom blocked her way. "Please, Lady Nimue," she pleaded, "If what you said is true, and you do this to teach our lord humility and kindness, pray consider this. What will happen to our land without her lord? At best, his vassals will do as they will. At worst, they will war with each other, trying to take the throne for themselves. So please, I ask you for a small reprieve. During the day... no, for just the afternoon, let the prince resume his true form, so that he may hold court and rule the kingdom." The witch regarded the former chambermaid thoughtfully. Then her lips creased in a light smile. "Very well," she agreed. Nimue gestured, and a wave of power passed over them, and settle into another part of the castle. "In the western meeting room," she pronounced, "while the sun shines through the main window, the curse shall be eased. Any of you who enter the room during that time will regain your original forms. When you leave, or when the sun has fallen, your new shapes will be restored. And know that if you squander this reprieve, it will break. Use the room for any purpose but proper business, and the enchantment will be gone. And you will have to find another way to govern." So saying, the enchantress vanished in a flurry of rose petals. # Magic must defeat magic "Go," the prince growled, "Find me anyone. Any hedge magician, or alchemist, or illusionist. There must be another who can break this curse. Or at least find a way to disguise it." So it was, after a few months search, that the wise old serving fork found the last true alchemist in the kingdom. And while his power and skill were not great enough to gainsay Nimue, lover and student of Merlin, he was able to brew a potion. It was slow to brew, and painful in effect. But it returned the prince to his rightful form for thirteen hours. But the potion itself was not without cost, if consumed more then once in a fortnight, it would tear the imbiber apart. Still, between the prince and his more trusted servants, they could try to keep the peace. It would have to be enough. # Spin Doctoring "Good people," the cryer exclaimed, "Hear of our great woe. A powerful and arrogant witch set upon our beloved prince. She made sudden and terrible demands, and when our highness bravely refused her, she cursed not just the prince, but his entire court and castle. That curse has made it nigh impossible for the prince to keep court. So we beg of you, our people. Help to keep the kingdom alive, do your duties, and assist others. And if you hear tell of the witch Nimue, report it to the castle, immediately, that we might find her, and undo her magics." The outcry was great, the people were united against a common foe. Though there were those who sought to take advantage, they were quickly found by the loyal. Or by the more shrewdly neutral. The crown was fractured, but the kingdom was stronger. After all, everything the bards reported was the truth. From a certain point of view. # Kingdom of Masks Okay, no story blurb this time. But have the prince announce that none may see him, that he will hold court in an exquisite mask. And that all who come to call must also wear masks. Set the nobles against each other, seeing who can match the prince's elaborate and flawless disguise. Offer loaner visors to those who come to court without a mask. After all, the prince should not judged by his appearance, nor do he wish to judge others that way. (thanks to WBT for the addition) [Answer] ## Have a regency until the king is normal again Whatever would have happened to Jeoffrey, there would be a regency. 11 years old is too young to be king, so in any cases, there would have been a regency untill his majority. Choose a regent that represent the king for the diplomatic visits and such, and make him rule alongside a council. When he finally found true love, declare him major, and the regency can come to an end. Regency was quite common, and was a good way to avoid chaos (wich lot of people want to avoid), so unless it last longer than few years, it will be accepted. Edit: Here is a good article to show how common regencies were. You can also see how old the king were during the end of their regency, and constat that majority age was not a constant. (thanks to aloisdg who link this wikipedia article) [List of regents on Wikipedia](https://en.wikipedia.org/wiki/List_of_regents) [Answer] Building on the excellent answers involving regency and grief, there's also that old trope: a body double. In that time period there are no photographs or TV. Only the palace staff would even know what the child-king looked like, and they're, well, in on it. Find an orphan (or maybe even a cousin) from another kingdom who looks more or less like the king looked before his transformation. Teach him a few basics and let him make an appearance when necessary. An 11 year old monarch would be expected to appear at official events (like the opening of the town fair or the wedding of some top nobles) and to sit at court to learn, but not to actually make decisions yet. Given that his parents were murdered, it would be wise of the court to keep him mostly out of sight the rest of the time. [Answer] One of the privileges of royalty is that they can be very exclusive of whom they allow in to see them. The official story will be: Jeoffrey is in seclusion and mourning the death of his parents, his missing staff were executed for allowing his parents, the king and queen to be murdered. Guards are posted and given orders that no one shall enter or leave without express written permission. The guards themselves will pick up proclamations that will be delivered to them through a rotating message slot. (think revolving door but for messages/packages. The proclamations will be then handed to the tax collectors, judges, et cetera, all authenticated by the existence of the royal seal. Eventually, a few trusted advisors will be allowed to meet with Jeoffrey personally, but only one at a time, so that there can never be collaborating witnesses. [Answer] # Barons, Dukes and Counts, oh my! If we're talking about monarchies, we're talking about feudalism, and if we're talking about feudalism, we're talking about layered bonds of liege and vassal. If a select group of people can be informed about Jeoffrey's sudden monsterism, and I don't believe there isn't an answer that requires this in any case, then the path is straightforward: The Dukes, Counts royal, and Baronets are informed of the situation, and tasked with keeping business going as usual. The notion that a king might meet with a peasant isn't absurd on the face of it; plenty of kings have held all sorts of audiences with all sorts of people, public and otherwise, but for a king to see no peasant whatsoever is also not absurd. An arrangement where the king only sees his court and his direct vassals is perfectly passable, at least for the relatively short timespan of 10 years that this involves. In fact, the structures of a feudal society allows the king to keep taking petitions from his people, proxied through specially uplifted baronets or through his other vassals; and for him to keep answering petitions. So TL;DR: The nested, hierarchical structure of feudal society makes a monarch in seclusion essentially a non-issue. [Answer] He's transformed into a hideous beast? Great! Now he looks seriously aggressive – almost like how warriors dress in horned helmets and furs and the like. So slap some armour round him, and make it look like he's just wearing armour with lots of fur and horns. Make up some rumour about how the young prince defeated with his own hands, the hideous beast that slew his parents. Now he's got an awesome story, to secure his rule. Why doesn't he ever take the armour off? Some think perhaps he wears it continually as he's compensating for being young. Some think he's sensible to wear armour the whole time as a young prince is considered by some to be a weak target for a power-hungry lord. Some think it's because the beast's fur he wears is a reminder of his dearly loved parents. [Answer] So if by any chance you are referring to "The Beauty And The Beast", the story was set in the 18th century. By the end of it (1789-99) the French revolution started and people simply began to "rule themselves". The forest village in the original story was also quite isolated so an absence of their prince might have been interpreted as "they fled the country" or "they have been killed". "Taxes need to be collected, court needs to be held, land needs to be defended from barbarians.." And this all could and would still be done by electing actual democratic leaders. [Answer] By conducting all business through musical dance numbers... Music is akin to magic (or is it a form of innate magic? the magicians are still debating), and makes us see things which aren't strictly true. It may provide enough illusion to fool the eyes of the public. And if anyone does get a good look, well, we all excuse some idiosyncrasies on the part of musicians, so it's probably just some flamboyant dress. [Answer] ## King went to a war Of course it's not that simple and the war lasting 10 years will be at least troublesome, moreover there will be a need of really trusted people around the king to keep that cover (of course the king will remain in country). There are historical cases, when it was difficult to find out if the king is alive or not (and the king actually died). One example can be Polish and Hungarian king Wladyslaw III of Varna. It took 3 years before the new king took reign after Wladyslaw's death because of problems in establishing if the king actually died or not. And that's despite sultan showing king's head. Most people never see a king. It's even less probable if the king is on a war. So you can keep the secret easily. The only problem will be with those really close to the king and those who have to hide the fact of king's absence in the battlefields. On the other hand when Suleiman the Great died, his death was hidden from soldiers for few days to prevent morale from plummeting (they were in a middle of a siege - successful by the way). If the war opens to more than one front line, it's easy to claim the king is either on his route between the lines or on the other line. A double can help to keep it quiet among the soldiers. [Answer] So, in a typical monarchy (including that of France), one of the non-negotiable public appearances you have to worry about is that the new king needs to be crowned. But you can't have a coronation with a monster. And a regent does not remove the need for a coronation: the king still needs to be crowned. You can send out letters and town criers and so on, saying that the new king is not currently in the kingdom. This is going to sound a bit suspicious, given that he was here last week and said nothing about any holidays/crusades/whatever, but let's say the people are reasonably gullible. You can instead say that he's injured and confined to his bed, or something, but this is actually rather risky. There was a surprising amount of public access to monarchs in the fantasy/fairytale era. In many cases the king's bedroom was one of the places he held court. The king's health is massively important to the kingdom (particularly to those positioning themselves for what happens if he dies), so it's not reasonable to expect them to take "sorry, can't say anything: HIPAA" for an answer. Anyway, suppose you come up with a ruse and the accession is publically known and acclaimed without anybody expecting to see him with their own eyes. You now have a period of time probably measured in months, before the people start expecting and then demanding a coronation. The big question then is, how secure is the king's control of the throne? If there is no challenger, or if the main challenger is somehow brought into the conspiracy as regent, then maybe you can ignore the popular demand for a coronation almost indefinitely. More likely, though, around the time that it becomes just completely implausible that the king can't come into the country to be crowned, somebody is going to make a point that there is no king in evidence, and therefore the situation is de facto vacant. So you get a rebellion. For what it's worth, Richard I of England was absent for much of his reign. But before that he was crowned in Westminster Abbey, two months after his father's death. Then again his succession wasn't exactly the smoothest and he had good reason to make clear that he was here and was king. In modern times, Elizabeth II was not in the country on her accession, and was crowned over a year later. But there was never any question that she really existed. Given the circumstances of the succession, challengers are quite reasonably going to demand evidence the prince/king wasn't killed too. The next in line is definitely going to say this unless somehow persuaded not to. Kings don't really need to do anything other than exist and be generally believed to exist. Other people can do all that finance/court/military stuff on the king's behalf, for as long as the people in the kingdom are prepared to believe there is no vacancy. Realistically speaking, therefore, I think you somehow need to fake a coronation (using an imposter or magic or something). That should shut people up for a while. Then in some ways it's actually better that your 11 year-old king is allegedly elsewhere. If he's around, one of these rebellious factions could try to capture him as a means to seize the regency or force him to abdicate (this happened to Edward II). If he's officially absent, then at least it's a fair fight between his conspirators (and whatever he can achieve himself acting covertly within the realm) and the rest. [Answer] ..and as the witch left, she realized nothing has changed, as the chef's second daughter had a secret crush on the king. Just in case, the king ordered the witch to be hanged, and banned witchcraft in his kingdom. End of story. Fair enough, let's say he found out who loved him, they got married, lived happily ever after. Whatever. If you're really into that stuff, I don't care. Women tend to be attracted to power, money, confidence, and some similar attributes a king is good at. The king is young enough, and the girl is full of hormones at that age, having weird crushes is almost guaranteed. Just ask your female friends if around that age they had a crush on their maths teacher or the ginger kid next door or the milkman. [Answer] I'd say that the biggest problem is the part of the curse that change all household. If those were fine, there is a chance for the business as usual, as mentioned in other answers. There may be multiple reasons why the new king can't appear in public, especially as there will be regency at least until he is 15. But household staff and troops will be a big deal (a cubboard turned maid will not go see her parents or lover fe). People will notice that a couple hundred men and women suddenly disappeared especially if it happened at the same time when the old king died. In this situation, I'd say the strongest vassals would try their chances. If one is objectively strongest, he will become a regent and try to take over the monarchy. He will either try to kill the king or send him to a place where he will have no chance to meet his love (dungeon/monastery/secluded island). It will not even be that difficult as he will need to have the household staff and troops etc replaced. If there are multiple strong vassals, a war for regency would ensue and at some point one of them will try to do the above (this would be the same scenario that happened f.e. after the death of Alexander the Great) [Answer] The people who get close enough to identify the king, have there position depending upon the king lifing. Once the king dies or vannishes, the inner circle gets burried with the king in a tomb Thus, the king lifes forever - or until someone within the circle wants to sacrifice the whole group for a better power setup. For the king to life forever, there has to be a ageless face, body doubles and a social circle capable of keeping a secret - meaning a social circle that is small. ]
[Question] [ Let's pretend for a moment that right now, everybody on earth was given the ability of flight. What impact would this have on the modern-day transportation industry? Physical restrictions on the ability of flight: * Maximum altitude is based on existing human survival limits (no more than 26,000 feet / 8,000 meters) * Maximum air time is determined by level of physical fitness * Maximum speed is around 30 mph / 48 kmh * Maximum distance is around 15 miles, again, can change lightly based on physical fitness * Roughly the same amount of physical exertion as running at a brisk pace [Answer] This is looking long-term...after the initial surge of people taking to the air occurs has died down a bit. The airline industry would be untouched...no one takes a plane for a 15 mile trip. Aircraft move much faster and fly much further than your flight-capable humans. The same applies to cross-country trains. Bulk goods transport would be unchanged, as a truck, plane, or train can move a lot more product than a flying human could. The automobile industry would take something of a hit as people stopped using cars for short commutes, but they would still need them to move large quantities of stuff, or to make any trip that is further than 15 miles, or that they want to reach in less time. (If you live out in the country, speed limits average around 55mph, letting you get to your destination in about half the time you could if you flew...allowing for the standard '5 over' travel speed) This would be a trade-off between your impatience to get there faster, versus the fact that cars cost money to operate and your new flight power does not. The industries that would, ultimately, take the biggest hit are short-range public transit that serve distances less than the flight range of a person. This would be most apparent in urban settings. Why pay money to a taxi to sit in traffic in NYC, when you can just fly over the traffic, and probably get there faster? Why take the subway when you could just fly to work? Again, people would still need some form of ground travel for any time they needed to transport something heavier than they can comfortably lift and carry for the flight time (I'm assuming a flying person can carry with them whatever they can lift), so transit services wouldn't completely shut down. All of that said, this assumes that people are willing to 'run' in order to travel...and a lot of people very much are not. Therefore, all of these impacts will be more marginal than if flight was effortless. [Answer] The impact on the transportation industry would be fairly minimal. In those parts of the world that have ready access to modern transportation, "running at a brisk pace" is something few people do regularly for any length of time unless they're doing it for sport. Read: People would be too lazy to fly themselves. Physical exertion means sweating and being out of breath, which is not socially adequate for many modern jobs with customer contact or in an office environment. There could be companies that accommodate for that by providing showers, but such companies already exist, if they want to be friendly to bike commuters, so not much would change there either. Since everyone can fly, it would be as mundane as walking is nowadays. Essentially, this is the same question as "Humans can walk, what happens to the transportation industry?" Well, nothing, because walking and modern transportation cover different needs. Humans would also still not be able to carry large amounts of goods, so the logistics part of the transportation industry would be affected even less than passenger transport. [Answer] I'm going to change your premise slightly You changed the maximum airtime to be related to physical health, so I assume the same happens to maximum distance. Using [this chart](http://www.pace-calculator.com/5k-pace-comparison.php) to determine run speeds for a 5k (since those take a bit over a half hour and you seem to want a 30 minute max), I did a comparison of the average male and female times based on age. Then I took the average speed and used that as an equivalent to 30 mph flying time. [![enter image description here](https://i.stack.imgur.com/gsZGj.png)](https://i.stack.imgur.com/gsZGj.png) Multiply it by a factor of 5.072 and you get flight speeds averaging at the 30 mph you want. This means you get people like Usain Bolt who can fly at 142 mph for short bursts of 10 seconds (based on his 100m time), and people who can fly at 60mph for a good 2 hours (based on some top marathon times). And these would be the maximum effect of flying. Note that this does hinge on a 30 minutes being the average person's limit for running, although that seems fairly accurate from my personal experience. A short interpretation Average people in general will be able to fly somewhere around 22+ mph up to age 50 for up to a half hour. But with recovery time (which for some people can be a whole day), it doesn't seem like they'd be using it for more than short or slow trips. This keeps the maximum distance around 15 miles as well, probably per day. Even if the ability to fly causes people to WANT to exercise more (which I doubt due to human nature), I wouldn't expect the numbers to increase much more than this standard. You can also adjust as needed to ensure flying isn't TOO beneficial. So how does this affect the transportation industry? Other than putting short distance uber's and taxi's out of business, it probably doesn't. If you assume you get 15 miles of free flight a day at the cost of nearly all your energy, I'm probably only using it to fly to a friends house. Also, there are a lot of limitations. You'll be burdened by what you're carrying, you need to watch out for weather, you'll use a lot more energy than taking a car, and you'll get all tired and sweaty and no-one likes that. [Answer] I'm going to make the following assumption: humans gain this ability suddenly. Maybe through a wave of strange cosmic radiation, or a dramatic change in earth's gravity, or some bacterial benefactor. (If this isn't the case, and humans have always had this ability, the industry wouldn't so much be changed as simply different.) The auto industry takes an early hit, as people experiment with this new ability. The taxi industry withers quickly. The airline industry is largely unaffected (though for the first few weeks, checkpoint-based airport security is a nightmare). Eventually auto sales will climb back to their original levels, though increased importance will be placed on how vehicles perform on highways (since it's a bigger share of what people now buy them for). The taxi industry is forever reduced, but not gone. A greater portion of road vehicles are semis and other goods transport. However, one thing to note (that nobody seems to have addressed yet) is that in addition to parts of the industry that have been reduced, others would open up. Suddenly, there's a market for all sorts of things that would've been useless before-- rocket boots and similar gear that, while unable to allow flight by themselves, can increase propulsion for now-flight-capable humans; masks and air tanks that allow for higher altitude flight; safety equipment for softer landings. [Answer] This looks roughly as good as riding a bike. In some parts of the world, a reasonably large percentage of the population ride bikes. These areas differ in density, climate and infrastructure compared to areas that do not. Possibly flying will require less infrastructure than biking. Which leaves climate and culture and population density to get penetration rates similar to biking. At first glance, vertical housing looks tempting. But the energy budget required to climb is a serous one, and without external energy input it isn't ever going to be as easy as a "brisk walk". If hovering is easy and falling a non-issue, then "lift loops" that pull you vertically might be used to replace elevators. Leaving high apartments/office buildings via the windows becomes efficient -- the height can probably be converted into horizontal speed, thus giving you a "free run". [Answer] Especially if humans were endowed with this ability suddenly, rather than gradually, then there would be some negative ramifications other than on the transport industry. Firstly, there would be a crime issue as lots of prisoners would simply fly out of the prison (if they were lucky enough to be outside and realised they could fly before the guards did something about it). Also, all the migrants in the camp at calais would simply fly the 20 miles over the channel into the UK. [Answer] We will see a resurgence of blimps following regular routes, used to tow flyers. People fly up to the blimp and grab a hook. They hitch a ride until they are near their destination, then fly down. Floating platforms will be great places to hold parties, mobile rock concerts, etc. Imaging a performer surrounded by a flying sphere of an audience. No need to build arenas and many more people can get a "seat"! Water quality will improve. People in areas with polluted drinking water can fly up to a cloud with a refrigerated jug and condense some water before flying down. (The amount of water gathered equals surface area of cold item times velocity of flight times time. The water is purified using graphene filters. Graphene is a nanometer scale, hexagonal grid, carbon mesh requiring ten times less energy to purify water than previous technologies.) EDIT: As pointed out, the concert idea needs more development. Considering how mosh pits and dance crazes develop, I believe that participatory synchronized flying will become a huge industry. A spin class today can accommodate a few score of people at most, so not worth the while of a celebrity to lead them. But in the sky with 3-dimensions, a celeb could lead a class of thousands and rake in big bucks. Thus you will need 3-d trained bodyguards. That will be another growth industry. As for gathering water from the clouds, the world will develop a large scale, floating infrastructure to act as waypoints for the flyers. Floating shopping malls, restaurants, etc. These semi-permanent places will handle the messy business of harvesting the water for us. Edit 2: People can walk, but use bicycles to go faster and farther. People can swim, but use flippers. Thus a new industry of flight-enhancing technologies will spring up. Jetpacks, glider wings or parafoils, small prop engines, the works. This will extend the range of flight, permit resting before resuming flight, etc. Aeoroponics will flourish, to supply food for the lofty crowd close to where they need it. [Answer] Short answer: nothing. As a transportation mode, it's too constraining. 1. You'd have to look out for the weather. I don't think you'd go fly with 90kph wind, or in a thunderstorm, heavy rain or generally unpleasant weather. So you'll still need another form of transportation in these cases. 2. You'd need appropriate gear to keep you warm. That could mean to carry a change of clothes with you. It's not a big obstacle, but it's a hassle you don't have to deal with in a car. 3. Most likely, you'd have to shower at work everyday. Not every company has showers. Socially, it's a big requirement. 4. Most likely again, you'd have to increase your breakfast budget. Effort requires energy, energy for humans typically come in food-form. I say breakfast in the context of flying to work every day, but that would apply to any trip. 5. Carrying heavy stuff. For instance, and related to 4, groceries. That would require a change of habit (more frequent grocery trips for instance) and would limit you to what you can carry. But since we're close to living in a world where drones can deliver pizzas in 30 minutes or less, this may not apply. 6. Crowded skies. I imagine what would Tokyo would look like if everybody flew around. People would probably fall out of the sky on a daily basis, and die. That's a danger for the people flying and the people down below. Also, drones if applicable. And that's only factoring for a one-legged travel. Traveling further would most likely infer stopping to rest and refuel (aka eat). The bottom-line is you'd need an additional transportation method for almost any situation besides just going out for a walk/run. [Answer] I'm aware that this might be considered a silly answer, particularly since I don't have numbers to back it up, but it's more than I could fit in a comment. My reasoning is that there are already some popular video games that provide players with the choice of either (effectively) flying, or using vehicles, and that we can examine play patterns within them. The closest game that comes to mind is [Just Cause 3](https://en.wikipedia.org/wiki/Just_Cause_3) that I'm playing these days, and other recent games with similar mechanics are [Batman: Arkham Knight](https://en.wikipedia.org/wiki/Batman:_Arkham_Knight) and [Saints Row: Gat out of Hell](https://en.wikipedia.org/wiki/Saints_Row:_Gat_out_of_Hell). Let's look at Just Cause 3. After some practice, the player can use a combination of a Grappling Hook, Wingsuit and Parachute to effectively travel across land areas (crossing water is harder), without the need for a vehicle ([example video](https://www.youtube.com/watch?v=xFDnFlHWRHY)). The game's physics (similar but not quite like earth's) make this method of travel very fast for going downhill, of limited maximum speed when traversing a level terrain, and significantly slower when ascending. "Flying" in the game requires a lot more effort and is (usually) slower than driving, but still, me (and many other players I know) use this kind of "flight" for almost all of our travel needs. The ability to easily cross obstacles (e.g. go above a city, instead of through it), and the fun(!!!) inherent in it, makes this mode of transportation very appealing. Of course this analogy is problematic, both since there is no distance or physical exertion limit in these games (but likewise no limitation on the use of vehicles), and in that by being relatively novel to me and most players, the use of flying could be said to not yet have reached an equilibrium. I suggest that further research be conducted. We should set up a game (or mod an existing game) where we could tune the various "costs" of using different methods of transportation, and use that game environment to collect a large dataset and analyze the way players' transportational preferences over a long period of time. [Answer] Breaking the transportation industry down there are several sectors that would be affected very little. Long-range human transport - trains, boats, planes and automobiles - would be very little affected, as they flight ability of humans is quite limited. Freight transport would be completely unaffected of course. Short range transport, most notably ferries, would have an initial decrease but would likely recover to normal once the novelty wears off. Humans aren't generally well disposed to exercise, and the stated flight speed is probably too slow to replace quick travel. Some niche transport industries would certainly suffer. If you could fly up a mountain to your favorite ski spot then the whole heliskiing industry would take a fairly significant hit. Ferries across short distances would have a significant drop in traffic. Hell, the recreational parachuting industry would probably disappear overnight. Ballooning would probably still be fine though... the enjoyment factor is pretty high for very little physical effort. A positive effect would be to reduce the impact of road congestion. It would be simple to park further from your place of work and simply fly into the office, and would take a shorter time than sitting in the morning traffic snarl. The reduction of congestion could be a persistent effect once people realize how much more convenient it is. There would be a movement to abolish all forms of powered short-range transport driven by environmental impact. Given the ability to fly at ~30mph at top speed (equivalent to running) or to loaf along at a slower 'walking' speed equivalent (if possible) this might be a reasonable concept. This could lead to a downturn in vehicle sales, driving the price of driving to work up even further and encouraging more people to fly to work. Another positive effect, this time on aircraft travel, is that passengers would now be able to 'bail out' of an aircraft in flight in case of accident or mechanical failure. Only the infirm would be unable to do so and would require 'special' treatment and safety measures that we consider commonplace these days. Airplanes could be more cheaply produced if the requirement of protecting the passengers in the event of a forced landing was removed or significantly reduced, could be made lighter and more efficient than current models. There would be some changes to structure to allow exit ports at the rear of the plane to be well clear of the engines and such, and the inevitable placement of first class passengers closer to the emergency egress is likely. All told the final impact to travel would be quite limited. Of more interest to me is the changes in buildings and support structures that human flight would enable. Whether natural or artificial, human flight ability would radically alter the world. But that's not the point of the question, so I'll leave it there. And oh, the possibilities for air sports. What a blast. [Answer] You are essentially asking if humans could move at 30mph up to 15 miles directly. Flying adds a cool factor and would affect society as far as regulation, but not so much transportation. Subtract all 30 mph 15 mile or less trips humans make, and you are left with a whole lot of other trips humans have to make. Prioritize the trips and the transportation industry goes on business as usual. [Answer] As mentioned elsewhere, long distance and bulk goods transport would be unaffected, and while taking to the air instead might ease commuter congestion, people are still going to want covered transport in bad weather. (Even just for air-conditioning in the heat or cold.) The major impact will be on pedestrian traffic, with people gaining to access areas they couldn't reach before. Certainly fencing would no longer provide security and even less privacy. Balcony and rooftop top pedestrian access would become a thing; once people overcome a fear of heights. Hilly terrain no longer be a deterrent and rivers would become less of an obstacle. Though wide rivers might need flying lifeguard patrols to save people who over estimate their ability to just nip across with a load of groceries or whatever. Coastal and river boating could become a lot safer, or maybe more dangerous; with people taking more risks "knowing" they can fly to safety. Its a tough call. [Answer] If men get this ability overnight, it would all cause a sudden change. A change of the business and living landscape that no one could think about before. Given an example, about traffic accident. Before, when your car crash into one another, you still have the chance of surviving. Not quite so if you are flying over 10 m high. The traffic rule need to be set for the new transportation mechanism as well, so that people won't go bumping into each other or bird or sky scrapper (I'm sure people will find a way to boost their flying speed soon, as it is the easy part). Many places that would be impossible or hard to get in would become possible. Like your favorite Disney park (they can't setup security overnight, no?). A lot of ticket-based systems would need to be reviewed as now people can simply fly over the fence. Depending on the citizen's attitude, it could be quite a mess. Or not, if government prohibit it at first, until everyone can fly responsibly. TL;DR: That's a breaking change, which will change the world forever. ]
[Question] [ Even the tallest mountains will be ground to dust with time. Given, of course, nothing sustains them (like tectonic activity which prevents mount Everest from eroding away too quickly, even making it taller each year). Let time pass and the elements will erode away anything that isn't supplied materials quicker than it is being ground down. And so the question arises: What could prevent floating islands from becoming floating clouds of dust or flat layers of floating dirt? My best guess at the moment are wind currents taking matter (dust and particles) from the surface up to the top of the islands, so they settle as sedimentary layers over the island's surface. This would mean the system grinding down the islands is the same keeping them from dissapearing or losing all geographical features. Which... I'm not too sure about. In my world the islands are locked to certain points of a magic spherical layer that rotates over the planet's surface around its axis. A good answer will provide a solution for the question that allows for (more or less) consistent renewal of lost material. All suggestions are accepted and appreciated. Make those creative juices flow! [Answer] Vegetation Thanks to animals and plants you can grow your island. Roots can overhang or pierce the island, getting nutrition out of the water and deposit it on the island in one way or the other. Even just sucking the ground water inside the island can help attract nutrients. Vegetation is crucial to hold things together and prevent erosion as well. Creatures will live there, able to get more out of the water and deposit there. It'll be a large nutrient rich environment that has a possibility to grow. An example is boats. Even though they don't hold nutritional value, they do offer purchase for some creatures. Barnacles can thrive, essentially growing the boat. It is such a mechanism that has the potential for a growing floating island. [Answer] Nothing. Eventually - over many thousands of years - a floating island will indeed be diminished until it's nothing but dust. However, individual grains of floating island don't themselves float forever because they aren't magically powerful enough. Instead, they gradually sink back to earth and are deposited in sediments and then compressed under great pressure, becoming new metamorphic rocks. In this process, the density of magical particles rises enough that the new rock would float... except that it's still underground. Every once in awhile, the erosion of the surface layer of rock will advance enough that the inner, floating layer escapes and becomes a new floating island. Through this cycle, though individual islands are born and diminish, the overall amount of rock in the sky at any one time remains relatively constant. [Answer] ## Where on Earth did THAT come from? A magical floating island BY DEFINITION is violating the laws of physics. But we want some reasonable plausible ways that these still exist. I will give some different options, some of which may or may not fit. First, we need to know how the islands are created in the first place, and why they don't fall. I'll assume island creation is intentional (someone makes island when they want one) or natural (a process causes them to arise). If the creation of new islands exceeds erosion, problem solved. So creation is either rare or non-existent, or the question is moot. * Island generation: If the islands follow a sort of track/ley line around the world, with all islands eventually going full-course, the "track" can eventually end up going inside the planet at some point. It sounds like the islands follow a sort-of almost LaGrange point, with the matter of the islands carried along in it. The oldest islands crash (if there's anything left of them) into the ground somewhere (possibly building a mountain) and when the track emerges on the other side, it rips a chunk of rock and surface out with it (the basis of a new island) Second, the island needs to be supported by all of its mass, not a point source, or else it would fall apart. So what IS or ISN'T island needs clear definitions. Further, the islands (to be perpetual) must be able to gain mass that might be lost by various means. I'll assume that there is a kind of gravity pulling island matter (IM) together. Any matter touching IM gradually becomes IM, and any matter lost to the island gradually becomes normal. Islands will thus tend to become somewhat spherical. Still-living matter cannot be IM, or else you'd have some VERY strange effects like people and trees growing upside-down (you may still have some very odd effects when birds swallow stones, or dead things convert to IM). Locally, the force creating IM must be sufficient so that you are not constantly losing some matter at the bottom where gravity and IM force are at maximum competition. How you handle water is up to you. If it sticks, then your islands will rapidly drown out and be balls of dirty water, so I'll assume it doesn't. If it doesn't, your islands will likely be arid to desert-like Loss is not inevitable if the force is sufficient. Like dust collecting to form an asteroid, this could be spontaneous. So a vacated point would gradually trap all the dust that blew there. But your question seems to assume loss of material, so how do we replace it? * Birds and bats and guano: Your islands will be havens for birds and bats. But especially if they are dry, they'll likely be only mediocre food sources. So birds and bats build nests, dwell in caves, and fly down to the surface or mid-air to eat seeds, bugs etc. If the island is dry, they'll likely bring nesting material from elsewhere. All these seeds, guano, and nesting material will become IM over time, building the mass of the island. * IM plants: Perhaps plants CAN become IM. They grow best on the top, but IM lichens, moss, etc. grows all over. As these plant grow, they fix carbon and nitrogen from the atmosphere, adding to the mass of the island. Vine-like masses may bind soil to keep it in place. The plants may have cactus-like abilities to trap water so it can't drain away * Lime scale: At some point in their travels, your islands touch down briefly in the water. This is also a great way non-magical people and animals can be introduced to your islands. Your islands, being dry but allowing water to leave, soak up large quantities of water. Then they slowly dry out, leaving behind all the dirt, salts and minerals that were present in the water. So like hard water buildup, the islands harden from all those minerals and gain mass. * People (broadly defined): In a magical world, floating islands are likely prime real estate, especially if you can fly, and aren't simply a traveler who hopped onto an island in the ocean that suddenly took off. But these islands don't have a lot of wood, or hard rock, or other building materials on them. So people bring cut stone, wood, food, loot (if the islands are wandering pirate bases...) and so on. People die and are buried. You could have thousands of years of ruins, graves, and midden pits littering the island, which might be more ruin than island. [Answer] Magical Stasis The floating Isle can't erode since the spell binded everything together. You can see the wind taking part of the dirt and some flowers away, but at the same time you see how little rocks move slowly towards their original position and little petals in the wind attach themselves after dancing free for a few moments. [Answer] Ice. The islands are sky glaciers, in large part (or in whole) composed of ice. When it is cold the islands grow from rain and snow deposited on them. In warm weather they shrink. If it were sunny and cold, water might melt on the sunny top and refreeze on the bottom, forming long icicles. [Answer] Just look at what prevents erosion of islands in the ocean! Wind and waves may not be the same but similar methods can be used to prevent them. Vegetation is very good at preventing erosion, and so are coral reefs if you want to make a version of those to grow on your islands. But that's just the tip of the iceberg especially if you're including artificial methods. You can also continually build up an island. Perhaps it is home to a volcano or it somehow picks up more rock from another source. [Answer] ## The Magic Binds Them In the same way as a planet would turn to a dust cloud without gravity, the islands would wear away to dust without magic. The magic provides a force that slowly pulls loose dust and clumps of dirt back to the existing islands. If the magic provided a small degree of attraction between every particle of the dirt and stone, you would have smaller islands slowly form, drifting until they get captured by the larger islands and eventually merge. Alternatively, it could be an extension of how your magical sphere holds the islands up. The sphere pulls all dirt and stone within it slowly to the fixed points, providing a mechanism for the islands to grow. The new material is pulled in and compacted, while water cuts canyons that eventually create isthmus and peninsula. These grow until the force of the magic pulling them in exceeds their compressive strength and they snap and "fall" into the rest of the island, creating interesting and unusual terrain. [Answer] Islands are like icebergs - calving from (depending on your preference) from either solidified magical lava spouted by magical volcanoes (my preference) or magical ice fields. Of course magical material fells off al the time, and drifts down when not bind tightly to other magical pieces. So it spreads all over the planet, making areas with more material more magical. Magical dunes? Magical beaches? Floating magical sandbars? Your choice. People mine the magical dust. It cannot float but it can make wearer lighter. [Answer] ## Volcanoes Each floating island - or at least each one that survives erosion - has a regular supply of new material through a volcano on the island. If islands can float, there is no reason to believe that matter could not spontaneously form in or be magically transported to the volcanoes, maybe even from the place the island originally was created on the ground?! (Ground based creation is just an assumption, of course...) Edit: This idea was already a side note in [an earlier answer given by @StarSeeker](https://worldbuilding.stackexchange.com/a/207490/3274), which I just stumbled upon. [Answer] If you consider erosion, you need to consider how these islands came to existence in the first place. Obsessing over "how do we keep material" while ignoring "how did that happen in the first place" is just pointless - especially as you can ignore erosion in a typical span of a story because it is a very slow process. It can be even a plot point: scientists: "yes, after all those studies we found that erosion is indeed taking place and will ruin our island in few hundred years." people: "These is enough time so let's party." 300 years later: some people: "oh, now we have only a decade left, we need to find a way to slow this down and/or get off the island before our city falls of the edge!" Other people: "why stop the party now, we are all going to die anyway lets enjoy while it lasts." If you found nothing wrong with the plot point, well... Erosion is much much much slower than that. You CAN'T use it as a such plot point (unless magic floating islands erode much faster for some reason). In our world, you would be looking at 300 MILLION years instead. Ok, with that clarified, what could be those island generation methods: If islands appear when there is enough floaty magicky stuff on Earth together to violently erupt and come to the sky, maybe that is all you need to have islands "regenerate". This is Cadence's answer. If islands are "living" (either trees or coral reefs), you have your regeneration also built in. Many other answers along that way. If islands appeared because that fine dust clumped together (like space stuff), then that could be your method of renewal too: You can have those islands collide and merge. Each individual piece of magic rock that floats attracts others (think gravity just stronger) and is perhaps attracted to special magical places as well so you have more islands at some places and less at others. Wind erosion will be taking pieces of those islands away. But every now and then, that dust will by chance clump together to create a small flat island. Then two islands will bump into each other, creating a larger island and a new mountain range. Because all magic dust always floats you aren't losing island-making-material, it just ceases to be a part of an island for a while - before it finds other dust and re-assembles. [Answer] ## The same force that's holding them up Let's say that there's some sort of gravitational anomaly that's holding the islands up. Let's also say that it's uneven, thus causing the material to rest in clumps. That means that any dust that blows past will tend to settle on the island, at a similar rate to the dust being blown off. If the island gets a bit too big, it's likely that material on the edges will get near the boundary, and fall away. But generally, the anomaly will hold it together. Think of it as a sand bar. It's being continually eroded, but also deposited, due to the peculiar local currents and eddies. Hence it flows and moves, but maintains its size. Or like the Lagrange points that hold the trojan asteroids together for example, only much more localised. [Answer] Floating islands are made of floating dust that gets progressively liberated from seabed. Indeed they don't erode, they grow. ]
[Question] [ Someone has discovered the secret of immortality (whoa, awesome!), but it requires what amounts to a human sacrifice and their spirit overtaking the deceased body (not as awesome!). Technically, it's more like possession than immortality, but it will be referred to as immortality since it's the soul of the same guy. This someone also happens to be the ruler of their country in a typical monarchy, but the reason they sought immortality in the first place is they're infertile. This country is also religious (hence the monarchy, they believe their bloodline was chosen by the Gods). I'd like this ruler to live for at least a few hundred or thousand years, but also publicly maintaining their throne into a more modern age. The original idea I had was to bring in a close circle of trusted elites that know the secret of the ruler, these elites having their own royal families with children hidden away from society, then the ruler picking one of the children to perform the ritual on to assume their identity every 50-70 years or so. This system might work a time or two, but then you run into issues with the ruler maintaining the trust of the royal families and potential incest within the royal families' descendants. There's probably a lot of other issues I've haven't considered yet, so I'd like some help figuring out how plausible this government could be. * How would the elites and ruler keep the secret of immortality hidden from the public? * How can the ruler keep the trust of the elites? (Perhaps religious influence?) * What other issues would this ruler run into, outside of the usual problems of immortality? [Answer] > > Three can keep a secret, if two of them are dead. - Benjamin Franklin > > > The only way this can be kept a secret is if the immortal (let's call him Bob) is the only person to know the secret. If anyone else learns of Bob's immortality, bad things happen - through jealousy, if nothing else. The key to Bob's plan, then, is to create a tradition: the king handpicks a successor, from a family other than his own, and anoints them in a religious ceremony shrouded in holy secrecy - a ceremony during which the old king dies. This religious ceremony also imparts Holy Wisdom and a touch of the Holy Spirit in a grueling spiritual trial. In reality, Bob is using the ceremony to possess the "successor" and take his place. The new king comes from a different family, because Bob is infertile anyway - and it helps cut down on the civil wars over rights of succession. The secrecy of the ceremony helps ensure that nobody stumbles over Bob's secret. The Holy Wisdom and Holy Spirit fluff are to account for wisdom only the old king had, and to cover up any mistakes Bob makes from not knowing all the details of the new body's life; since it's religious, nobody should ask too many questions, right? The old king dying part should be obvious; just make sure to imply that he ascended to Heaven... If the ceremony absolutely requires another person, things get much, much more complicated. At that point, Bob is probably best served by creating a small branch of the Church, devoted to the ceremony, and indoctrinating them from the earliest age possible. Even then, Bob should try to keep them as much in the dark as possible - couching everything in religious terms. Beware the backlash should this heresy ever be discovered... I'll leave it as an exercise for the serious student as to how Bob creates this tradition in the first place... but receiving the Word of God as to this new ceremony, combined with a "willing transfer of power", might go a long way. [Answer] Take a look at the Dalai Lama and how his spiritual succession is handled. Assume it is real (I make no claim one way or the other) and there you go. Hide in plain sight. <https://en.m.wikipedia.org/wiki/Dalai_Lama> [Answer] ## Tell no one, deal with possessing a child Studies [show](http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0147905) that the greater number of individuals involved in a conspiracy the less time it takes for that conspiracy to fall apart, ie, the time a conspiracy is secret is inversely proportional to the number of people involved. Don't tell the nobles. Don't tell anyone. Since there's a cultural belief in God, miracles can happen. Do the following: 1. Proclaim the queen pregnant. Keep her in seclusion for nine months. You don't want anyone to know that she's not actually pregnant. If the king's infertility is known, pronounce it as a miracle and keep going. 2. Steal a new born infant from somewhere. Make sure it is healthy and from smart parents. 3. Take the infant home to castle. Proclaim the child as your heir and begin to raise it. 4. When the child grows up and no longer requires a regent, possess the child and take over. 5. The old king dies (and everyone is sad) but the "new" king goes on living. Some will notice a change in tone from the new king since the personality of the old king now inhabits the new king. 6. Repeat as necessary till monarchs go out of fashion. [Answer] Sarah A Hoyt's book Darkship Thieves (and the sequel Darkship Renegades) has a similar sort of setup: > > It happens via medical means rather than magical. The ruling elite basically take over the bodies of their heir when the kid matures. Keeping the secret is basically fairly easy as far as the public goes - because it's a new body, it looks like normal inheritance, and behavioural changes can be passed off as down to the new responsibilities. > > > Since all the elite do this, anybody who finds out gets squashed - none of the elite want their heirs/donors finding out and messing the system up. In your scheme, with only one immortal, probably the simplest thing is not to tell the elites, and secure their loyalty by marrying them into the royal family. Or extend the immortality scheme to the elites as well. [Answer] ## Knowledge is Power He does not need the support of anyone. If he have the knowledge of a 70 year old in the body of a 5 year old he will be taken as a genius and rise faster trough the bureaucracy of the state. You can even make you setting a democracy and he will always rise to the presidency. Take Bush father and Bush son in US. Take Clinton husband and probably Clinton wife in US. Look at US and Brazilian senate and congress and you will see at high offices there is many sons and daughters of someone. ## Options 1. A ritual to chose the next emperor. I saw a round table movie where the Excalibur was placed in a waterfall by Merlin with a mechanical device that will only release it if the sword was twisted in a specific way. Then, when he was certain that Arthur was his chosen, he hinted to him that he needed to twist the sword. On your setting you do not need to cheat, the kid emperor will know everybody, knows a lot about the bureaucracy of the state, knows about the skeletons on the closets. An ritual consisting in knowledge of the bureaucracy, secret rituals, administrative skill will always be won by your young emperor. 2. School of management. Ramses II, started a sort of business school that was known as the "sons of the emperor" and declared that all of those kids are their sons and therefore eligible to the succession. Those kids was put on public offices all through Egypt and when the appointment was about proven efficiency. He actually appointed as successor one of his genetic sons, but the idea is interesting. Your emperor can appoint a kid of the school "sons of the emperor" as the successor. Of course he will appoint the kid he intends to take as host. And this may even have a religious meaning to him... he actually believe be appointed by god and see the scores of the kids on the tests as god sending him the perfect host. And this also serves as a backup, if he die unable to complete the ritual he will left good kid in control. The appointment can be kept secret. Can be part of the emperor's will so that no family tries to kill him. This also allows the emperor to appoint a new kid each few years since he does not know when he will have to perform the ritual. 3. All of the above you can left the "will" out, and make the "sons of the emperor" school combined with a ritual. That way he will be selected. 4. Say the truth without saying the truth, the emperor declares that had a vision where God said that his knowledge will be passed on to some kid on the realm. 5. Hide resources the emperor can make strategic division of the knowledge and resources in the way only with his knowledge some resources and bureaucratic approvals can be done in able time. That way when he "dies" a crisis of massive proportion will start. Then, a decade latter as teenager he will begin to solve the crisis at local levels and rise up fast. In that case you probably will want the "emperor sit" be available though the crisis. That can be made by the religious claim that he will reincarnate and people needs to look for him (like the lamas do). Or make the setting a democracy with the presidency with no real power, place the power in the figure of a super-secretary that can be appointed. 6. Plain old democracy. Since he have privileged knowledge about passwords, cracks in the bureaucracy, persons, he probably will rise up quickly in a democracy. He will be first minister for almost entire life or reelected president or speaker of the house for almost entire life provided there is no limit on reelection. In such a setting the role of the president/prime minister/speaker of the house probably will evolve in a bureaucratic web that only he knows to unravel, not by design, but by simple incompetence. After a great president, will be elected a bad one (while the emperor host body ages) because he can't do anything. When the emperor rise everything is fine and people will not blame the bureaucracy and change it. They will blame the placeholder president. In democracies laws evolve to prevent a bad president/prime minister to make severe damage and that probably will not happen in this setting. That is what will make the web of bureaucracy and mostly assures that anyone but the emperor will be able to make a good government. I much prefer the option 3 or option 6 because has historic elements that supports their credibility: I mean the perpetuation of family politicians and Ramses II child of emperor school. Those options allow for a good or evil emperor. The emperor can simple believe he is not killing the child, but merely giving his knowledge to the kid making he or she the right successor. Or that is an sacrifice for the good of the country. Option 3 also explains why he will live surrounded by children and why they will visit him on his death bed. The kid that was sacrificed may not even be the last to visit him. They can keep the body on life support or say he is in coma. The difficult thing is how the emperor lives to be 70 Half emperors in history died assassinated by their successors quest of power. The other half was killed because they become mad out of the fear of being killed by persons close to them (I am exaggerating a bit here). Is difficult to believe an emperor will live to be 1000 years old. I think the democracy scenario is better suited for longer times because as an super-secretary he will not be target of house-of-cards and "et tu, brute?" types of conspiracies. As the super-secretary he will be on the safest of the positions while retaining all power. And his different personas will be known by their skill in history. He can even survive a few coups and risen to power again. His country can change from an monarchy, to a communism and then to a democracy and he will still be on the highest offices. As an super-secretary known to have passion for the country, known to be critical to those above him when they made mistakes, he will probably be included in most coups. This can start on his first life. A coup can happen just before or shortly after his first reincarnation. Since he has no known sons, his new persona is not killed. But since he knows a lot about the state he became the primary advisor to the new government. Since he solved a lot of problems he become addicted to the feeling of starting over and be appraised as a genius kid. [Answer] This is mostly the plot of the very first episode from [Métal Hurlant Chronicles](https://en.wikipedia.org/wiki/M%C3%A9tal_Hurlant_Chronicles). Spoilers ahead: In some random kingdom, everyone hates the king, because he does what every evil king does (killing, taxing, restraining freedom etc.). Every once in a while a tournament happens, where the best warriors from the kingdom come to fight each other. The winner is supposed to become the new king. > > In fact the king is some kind of alien or whatever super technological advanced being, who when he is about to die, use the tournament to select his next host and then implants his own brain inside the winner. This way the same king has been around for centuries without anyone ever noticing. And everyone in the kingdom loves the tournaments! > > > [Answer] This setup loosely reminds me of that in [Sten Chronicles](https://en.wikipedia.org/wiki/The_Sten_Chronicles), which feature openly immortal Eternal Emperor. It's sci fi rather than magic, but much applies. Without going into lengthy retelling and spoilers, his reign hinges on following things: 1. Immortal, both details and implementation process of which are exclusive to him. 2. Irreplaceable, the whole energy supply for the Empire hinges on Emperor personally. No Emperor = lights go out. 3. Assasination/kidnap–proof, the specifics of immortality implementation allow Emperor to return after physical destruction of his body, which also allows to use self–destruct as protection against kidnapping. So being immortal is "easy" (sufficiently advanced technology / magic / whatever). The hard part is being immortal and protect yourself from being out of power and/or dead. It's much less fun being immortal forever, thrown in a jail cell. Or shot in the head few days short of next reincarnation / whatever. Such monarch would need immense leverage so that getting rid of him is highly inadvisable and preferably impossible / unrealistically hard on top. [Answer] None of the answers, at least to what I have seen, deal with the issue that is possessing a child. A child, whether he has the soul of the emperor or not is just that, a child. The emperor needs to select a child, and raise them to be an heir to avert any suspicions. This is normal, as it would be the course in a normal case. Where this differs, is that when the emperor is on the verge of death in his current body, he can transfer to the heir, telling no one. From here, he can continue to be the ruler of the empire, and no one will know that he is now possessing the body of the, hopefully by this time, fully grown adult heir. EDIT: Read this part of the comments after typing this, leaving it in because in my method it is possible for the heir to have already had a child. You also never mentioned if he remained infertile when switching bodies. If this is not the case, once he switches the first time, he can simply have a child, and continue down the line of taking over his child when the time comes for him to "die" yet again. This cycle could, in essence solve the problem of keeping as secret, as he needn't tell anyone, as well as allow him to easily keep the throne. This power could also be used in case of a rebellion. Should his reign ever be threatened by rebellion, he can simply move into the bodies of one of the rebels, stating that he killed the emperor, and usurp the throne, again ridding suspicions, keeping his rule. Sorry if this answer is a bit muddled and convoluted, my brain thinks in weird patterns. [Answer] He need not tell anyone, but the extent of his knowlege will eventually lead to his downfall, many "generations" later. As in any concentration of power, He is surrounded by a set of insiders; Royals or Peers, whose devotion to him is essential to their position. A rising Technologically (or magically) sophisticated upper middle class resents the privilege of the "Royals" He counters the consolidation of their power by creating a sschool for promising young people, much as the early Chinese Emperors did in requiring all officials to to pass a series of Civil Service Examinations, and permitting all his subjects to try for admission to the school, regardless of their sex, social standing, family history, or personal reputation. They only need to be physically attractive, even tempered and free from revolutionary influences. His personal safety in the midst of this cultural dissonance is assured by a cult of assasins, ever ready to deal with opponents in apparently innocent accidents. While he alone triggers the event, his succession is a public spectacle occurring every 66 years or earlier if poor health or public sentiment intervene. He longs for a fresh body, with no ills, pains or bad reps. The end comes when the succession of new bodies eventually relieves his inability to father children, and his favorite gives him a beloved daughter. He is compelled to select her as his successor, and he must decide if he ends his life or hers. [Answer] Green got half the answer, I'll finish it: Tell no one, the queen is not in on it. Instead, when it's time for a new generation he artificially inseminates the queen. She doesn't realize it's anything other than the lubricant he typically uses. Possess the child as soon as he's old enough. ]
[Question] [ My question is about unusual hereditary traits in humans. I'm new here and this is my first question - apologies in advance if I've accidentally messed this up or covered existing ground. I'm writing a post-apocalyptic story in which the protagonist realises partway through that a child he's rescued is biologically his own. This is a post-apocalyptic earth, relatively realistic, so genetics have to adhere to our current real-world rules. There is no genetic testing in this future, though the characters in question are educated and understand genetics and hereditary principles. My question is: in what way/s could I show that (child) is the daughter of (Male B) rather than (Male A)? In this scenario those two men are the only possible fathers. I looked into birthmarks, but from what I can find, they're not actually hereditary, and this was just one of those little literary cheats - one I'd rather not use. I've also considered having it become obvious that the little girl is colourblind, and so is (Male B), but not (Male A). A girl can only be colourblind if her father is (AND her mother carries the gene, but that's besides the point). This seems like a fiddly, talky way to handle this reveal though, so I'm wondering if there's anything like a birthmark - a medical condition? A distinct but subtle physical feature? - that can only be inherited from a father, can be identified visually, and provides incontrovertible proof of parentage. [Answer] While you point out there is no genetic testing, & I can certainly understand why that would be the case, Blood typing is a skill that is likely to not have been lost. Specifically because it is so useful to medicine, making possible blood transfusions. It is very true that while it cannot conclusively prove paternal parentage, Blood Types can absolutely rule out one of the fathers, if types are not compatible. And that can be found out in the oddest of ways... Here is a site that gives a pretty simple chart of parental types and possible resulting children's types: <https://canadiancrc.com/Paternity_determination_blood_type.aspx> Here is a site that gives a pretty simple explanation of how to test for blood type: <https://www.nobelprize.org/educational/medicine/bloodtypinggame/2.html> There is a movie that talks about something along these lines, and uses as a plot element some of the other responses about genetic characteristics: [The Switch](http://www.imdb.com/title/tt0889573/) It was a pretty fun watch in a chick flick sort of a way, might be worth taking a look if you enjoy movies and don't mind Jennifer Aniston or Jason Bateman in a lead role. Another movie that gives some insight into the whole Blood Type can eliminate potential paternal situations is: [Made in America](http://www.imdb.com/title/tt0107478/) [Answer] Since you are creating a post-apocalyptic (and if that apocalypse was either nuclear or biological in nature), the genetic proof you are looking for might be a mutation which is not currently present in the human gene pool. Look around the animal kingdom for examples of biologically possible traits. Perhaps something from our genetic neighborhood, like a prehensile tail, or maybe something from a little more distance, like reflective cats eyes. When you throw a little nuclear fallout or a few gene jokers into the mix, almost anything becomes possible. [Answer] Recessive alleles only show if two copies of the recessive allele are inherited - you couldn't get blue eyes unless both parents had the recessive allele for blue eyes. These pages have some suggestions about dominant/recessive characteristics: <http://www.blinn.edu/socialscience/LDThomas/Feldman/Handouts/0203hand.htm> and <http://faculty.southwest.tn.edu/jiwilliams/human_traits.htm>. If the child knows the mother (and/or both of the men do), they might be able to rule out one of the men if the child exhibits traits that only come from inheriting two recessive genes. Some initial thoughts are: * Having red hair * Having earlobes that are attached to the head * Being susceptible to poison ivy (just imagining the child falling into a ditch, both of the men getting the kid out, and finding out that one guy and the child come out in a huge rash...) * Not being able to roll their tongue * Being able to fold their tongue And there are several more in the links above. [Answer] Answering outside the box: consider a [matrilinear society](https://en.wikipedia.org/wiki/Matrilineality). In these societies, the heir is the child of the queen/princess/[women whose status grants power]. Thus heir identification becomes only a matter of witnessing the royal birth ([which was apparently usual](http://www.dailymail.co.uk/news/article-2373851/One-tradition-wont-missed-Home-Secretary-longer-required-witness-birth-royal-child-ensure-isnt-imposter.html)), and there is no bastard problems. Note: matrilinearity does not necessarily imply matriarchy. If patriarchy is required in your story, you can for example say that the queen is a descendant of god (chief of religious power), and her husband is the executive ruler. [Answer] I would suggest webbed toes. Not immediately visible, but still hereditary, and it doesn't have to be a hindrance. <http://luken.us/wmluken2/syndactyly/syndactyly6.htm> If the hero has webbed toes and the kid does too... [Answer] Simplest answer I can think of: eye color. You need to get a recessive gene from both parents to express light colored eyes. If the child and Male B both have dark eyes, but Male A and the mother both have light eyes, that is undeniable proof that Male B is the father. Keep in mind, eye color can change when the child is very young. So if the kid goes from having light eyes to having dark eyes, that'll cause a lot of drama. [Answer] Here's a pair of genetic conditions that could become obvious in an 'epiphany' (this would /have/ to be an X-linked disorder, since she doesn't get a y-chromosome from him) 1) Hemophilia. His daughter has a nose bleed that just won't stop, and is very careful about getting hurt. This would also mean they have similar mannerisms for avoiding injuries (subdermal hematomas can be fatal in the case of hemophilia.) 2) Fabry disease, which causes skin-speckling that could be mistaken for freckling, and a whorl-like pattern in the corneas. That would be the sort of thing that could be a fire-light reveal. [Answer] Are you after a general, non-specific answer, or one that only applies in this case? A coincidental confluence of genes? And do you want a sudden, immediate, obvious recognition, or do you want it to occur over time? I have seen fathers and daughters whose facial appearance is so unusual, and so identical, that there can be no doubt about parentage. For example, all of the following: buck teeth, incisors, wide brows, long nose, cauliflower ears, button chin. Not just one criteria, but the entire facial image. If it absolutely matches one male, but bears absolutely no resemblance to the other male, it would be conclusive. Add quirks of behavior (a particular cough, a particular way of snuffling up the nose, a quirky way to fold the legs while sitting) that are similar would be added proof. Not all fathers bear a close resemblance to their daughter, so NOT looking or behaving alike is not conclusive proof they are NOT father and daughter, but when they do look and behave alike, parentage is striking and unavoidable. The daughter got ALL the 'image' genes from the father, not just a random sample. This would be the exceptional, unusual case, not the 'bell curve' standard expectation. But it IS credible, and does happen. Sort of like the idea that twins are not always identical, but when they are, it is striking. The vagarities of genetic inheritance being random. Sometimes, you roll a Yahtzee on the first throw. [Answer] Maybe he's the only white, or black, or Asian man in town; the child would be mixed race, easy to see. Or maybe he has one of the numerous [anatomical variations](https://en.wikipedia.org/wiki/List_of_anatomical_variations) and again he's the only one in town; for example, a few people have a dedicated [extensor muscle for the middle finger](https://en.wikipedia.org/wiki/Extensor_medii_proprius_muscle), or an [accessory nail](https://en.wikipedia.org/wiki/Accessory_nail_of_the_fifth_toe) on the little toe; or lack a [palmaris longus](https://en.wikipedia.org/wiki/Palmaris_longus_muscle). Or maybe the inherited characteristic is not anatomic. He may be very good with numbers, or have an exquisite sense of equilibrium, or [perfect pitch](https://en.wikipedia.org/wiki/Absolute_pitch); or an absolute sense of time, like [Jack Reacher](https://en.wikipedia.org/wiki/Jack_Reacher). Anyway, he's a man. In the absence of genetic testing the old Roman rule applies, [mater semper certa est](https://en.wikipedia.org/wiki/Mater_semper_certa_est), pater incertus. [Answer] Everyone in my maternal side of family has a mole that looks exactly the same (a little bit like Australia's map). Each one of us has it in a diferent place in our body, but we all do have it. I think this is used too proving Jace is not Valentine's son in Shadowhunters by Cassie Clare [Answer] As you said you want a sudden reveal like finding out a matching birthmark under clothes... From your comment: > > I definitely want the recognition to occur suddenly, but after they've known each other a few weeks. A flash of recognition works better for the story than a slow build. I'd want something equivalent to seeing a birthmark previously hidden by clothing and recognising it as near-identical to your own. > > > Well, you can still do that, as long as the birthmark is melaninic (brown) instead of vascular (red / blood). Only the vasculars aren't inherited. The melaninic type is. [Answer] You are looking for a trait, that satisfies the following condition: ``` If the child has the trait, then the father must have it. ``` There are a few traits like the colorblindness you mentioned that give you precisely that. However, if it is known whether the mother had the trait, the above is implied by: ``` If the child has the trait, and the mother has not, then the father must have it. ``` Now, the beauty of this formulation is, that it fits any dominant trait: You cannot inherit a dominant trait unless either of your parents had it. Now, the wikipedia has a list of traits that could be useful to you: <https://en.wikipedia.org/wiki/Mendelian_traits_in_humans> Among these is the lactase persistence trait which can easily said that the mother did not have it due to her origin. This is a nice common trait, that can easily be tested, and that's a tell-tale trait if looked-at from the right angle. So it's something that can easily be noted early on without anybody being any the wiser. Later on, when you need to reveal the inheritance prove, you can let a biologist, doctor, or other knowledgeable person make the connection between the lactase persistence and the parentage of the child. But, of course, the colorblindness trait would definitely work due to being inherited via the X chromosome (which makes it useful for exactly your case, even though it's recessive). The only problem with that is that it's so rare that it looks odd for a character to have without a reason. [Answer] Something like a Mallen streak... with both parent and child initially being so thoroughly dirty that they can't see each other's hair colour oddity... or both wearing headgear that covers it... or it being considered a mark of something bad so it's normally masked by dye and gradually grows out in the child. Or as in GoT... a blond child produced from a family that only ever produced black-haired children. [Answer] Most of the really interesting genetic traits are "X-masked" so they don't usually show up in female children because they have a healthy copy of the gene from their mother. There are a couple of unusual traits that could be diagnostic, for example my wife is a carrier for an odd mutation for blue eyes which instead of being pale blue are extremely dark, this blue mutation is recessive to brown like the normal pale blue/grey eye mutation but dominant when mixed with the normal mutation, it is also very rare constituting only 2% of all blue-eyed individuals, there are similar "minority recessive" mutations for green and hazel eyes. Any child that inherited the gene for such a mutation would get the pheno- as well as geno-type, provided mum is a carrier of the "normal" mutation, and there would be a very small donor pool to choose from when playing "who's the daddy". [Answer] The father and daughter could share a trait such as [heterochromia](https://en.wikipedia.org/wiki/Heterochromia_iridum#Congenital_heterochromia), a visible (but not debilitating or obvious), rare condition which can be inherited. [Answer] A genetic mutation on a dominant autosomal gene, that started with the father, and was passed on to the daughter. NO (as in zero) chance the other male would have it. > > However, in some cases an autosomal dominant disorder results from a > new (de novo) mutation that occurs during the formation of egg or > sperm cells or early in embryonic development. In these cases, the > child's parents are unaffected, but the child may pass on the > condition to his or her own children (illustration). > > > [If a genetic disorder runs in my family, what are the chances that my children will have the condition?](https://ghr.nlm.nih.gov/primer/inheritance/riskassessment) Another trait would be [six fingers](http://genetics.thetech.org/ask-a-geneticist/polydactyly) > > So why if there are many dominant versions of genes that make six > fingers is having six fingers rare? Well, those versions of genes are > rare. You don’t meet many people with extra fingers or toes. > > > NOT having six fingers if the father has six fingers is not a good indicator, but having six fingers when the father has six fingers is a very good indicator. . [Answer] > > ... , so I'm wondering if there's anything like a birthmark - a medical condition? A distinct but subtle physical feature? > > > Other answers already suggested a number of genetically inherited conditions/mutations/diseases. My suggestion is to go into the opposite direction and use a hereditary resistance to a particular infectious disease. Pros: This trait is: * realistic ([Disease Resistance May Be Genetic](https://www.sciencedaily.com/releases/2007/08/070830150014.htm)); * incredibly subtle ( there is no way to tell if someone is resistant to infection before the next outbreak); * doesn't require any particular technology to check it. Cons: * can't be identified visually; * to successfully and undoubtedly identify someone this trait should be incredibly rare, to the point of being unique. > > ... the protagonist realizes partway through that a child he's rescued is biologically his own. > > > Here is the scenario. The protagonist has an unusually strong resistance to a highly contagious infection. During the last outbreak, he was the only one who survived in his town/city/village/cave/commune. As the only one who could safely travel to plagued cities, he was sent to pass messages/resources to and from quarantined safe-zones. The devastating epidemic occasionally ran out of resources, stopped and didn't occur again for 15-20 years. Now, if during the next outbreak the protagonist's daughter is the only other person who displays increased resistance, then this is a good reason to assume paternity. [Answer] Even if you can't directly measure DNA, you still can observe some characteristics (like hair color, eye color, some types of colourblindness... etc). These are the phenotype. How this works is quite complicated, but I will use a simplified version to explain it. Keep in mind it is only vulgarisation. For colourblindness there are two possible genes. One more prone to colorblindness (let's note it CB) or one that makes people able to see colours (let's note it NCB). People have two genes (one from their mother, one from their father), so basically one person can have either (CB,CB) , (NCB,NCB) or (CB,NCB) as a genome. A person will be able to see color with (NCB,NCB) or (CB,NCB), but people with (CB,CB) won't. So with this example one can test if someone has a (CB,CB) genome or not. With that known you can build situations where it is impossible for the other man (male A) to be the father. For example Male A and the mother could be both colourblind (so with a (CB,CB) genome) and the child not colourblind (which would be impossible if they were his parents since none of his parents has a NCB in their genome). You can replace "colourblind" with any recessive trait to get the same scenario (@KPrice gave a list in his answer), and make the surprise come from anywhere (Male B could discover that the mother has the trait, that Male A has the trait, or that the child doesn't have the trait). Of course this won't prove that Male B is the real father by its own, but it proves that Male A isn't, which is what you were looking for. [Answer] Consider a society where some people are constantly monitored, and physical encounters can be looked up in people's logs.In a post-apocalyptic world records could be logged manually for some key people. If the mother has interacted with only one man during impregnating ovulation, then there can only be one possible father. Also consider preterm birth, which may offset the period to search through. [Answer] You could find some way to reveal something about the girl's past to make it obvious that he is her father, but other than that idk [Answer] Humans are actually in the process of developing a 4th color gene. In the post apocalyptic world this genetic mutation has been accelerated causing the gene to be fully developed. With the fourth color gene only people with this can see a certain color beyond normal ranges of 3 color genes. A test of showing the color to the father and the offspring would prove its his if the other father cannot see. ]
[Question] [ So we all know that interstellar starships that travel at high relativistic speeds, like 50% c or above, would be very susceptible to getting destroyed just by a grain of salt hitting it during travel. We know we can stop this from happening by using a physical barrier or the use of plasma shields. [![Artist's rendition of a ship with a physical barrier](https://i.stack.imgur.com/YfZHH.png)](https://i.stack.imgur.com/YfZHH.png) [![Another artist's rendition of a ship with a physical barrier](https://i.stack.imgur.com/kmXaT.jpg)](https://i.stack.imgur.com/kmXaT.jpg) But I was just wondering how about solar sailed ships? The ones whose diameters outsize the main ship in of itself. How can they be protected during a travel in interstellar space? And I know traditional solar sails won't travel that fast but what about photon laser sailed ships that can theoretically allow travel at 30% to 50% lightspeed? How can it be shielded from such obstacles? [![A ship with a solar sail](https://i.stack.imgur.com/dj4d1.jpg)](https://i.stack.imgur.com/dj4d1.jpg) [![A ship with a solar sail being driven by a laser](https://i.stack.imgur.com/LyTL9.png)](https://i.stack.imgur.com/LyTL9.png) I'm not really a physics type of guy so I just wanna see what you guys have to say. [Answer] Generously spread the sail surface with self repair nanobots. Any impact with dust or sub-dust size object (which is more likely to happen) will pierce a hole through the sail (and leave a cloud of plasma behind it). Just "patch" it using the nanobots and keep traveling. For larger objects between the size of dust and meter sized asteroids, I would better opt for selectively close the sail upon detection, since damage might be too extensive to repair. (how you detect it in time is another story) For even larger objects, well, sorry, no much to do once you are heading at 0.5c on such a bulky obstacle. [Answer] A tiny piece of space debris is dangerous to the ship, as it may hit people, mechanisms, or fuel. But the damage to the hull itself would be negligible. It could simply be patched. The hull is the least of the concerns there. Solar sails typically don't contain people, mechanisms, or fuel that could be damaged. A solar sail with a tiny hole in it could also be patched, whether with [nanobots](https://worldbuilding.stackexchange.com/a/149915/2113) or with a regular robot and a patching kit. You could even send a human out to do it, although the human would then be effectively unprotected from more space debris. For that matter, for some substances, the hole itself might be self-patching. Consider an opaque form of ice, say [frozen mercury](https://education.seattlepi.com/causes-mercury-solidify-4222.html). The impact would liquefy the mercury, which might then close the hole after it. It would require some experimentation, but it seems like there should be some form of matter that would work like that. Mercury may not be that form of matter. It's just a possibility that came to mind. Remember that at space temperatures, even things that are normally gases would be solid. Perhaps not [hydrogen](https://physics.stackexchange.com/q/293587/227500), but something should have a triple point and liquid [cohesion](https://en.wikipedia.org/wiki/Cohesion_(chemistry)) that would work. Beyond that, the hole would be tiny relative to the size of the sail. A big hole would add torque. But for the typical worry, the hole would be so tiny as to not be noticeable. The far greater cause of torque would be for the light source to hit unevenly. So if the sail can handle an imperfect light source, it should be able to handle tiny holes. It would also be common to spin the ship to get an artificial gravity effect. This might offset the torque issue by constantly changing where the torque is. [Answer] Why only one sail? The word here is redundancy. Your sail will take damage, that much is pretty unavoidable, but the great thing about solar sails (unlike wind sails) is that the continuity of the sail isn’t important: only total surface area is. So break up the sail into a cluster of smaller sails. If one gets damaged then unclip it, replace it with a sail you had folded in storage, and repair the damaged sail. If you make the sails manoeuvrable you can shift the distribution of sails to keep thrust even while the damaged sail is replaced, and even selectively open holes in the cluster to allow detected obstacles straight through. This will be a tricky engineering challenge. Dynamically controlling the attitude of the sails, the tension on whatever you’re using to tether them to your vessel and also managing the distances between the sails is non-trivial to say the least. Photonic laser thrusters (basically satellites pointing lasers at each other) could help in formation keeping, as could angling the sails (though that would reduce overall thrust) but it’s not simple, to say the least. It does offer a lot of glorious plot hooks though... [Answer] A solar sail is certainly fragile, and can easily by punctured. However, a puncture won't reduce the total area of the sail by very much, so it won't reduce the effectiveness of the sail by very much either. The real danger is tearing of the sail, because that can greatly reduce not just the area of the sail but also your ability to control how the sail is pointed. Therefore the sail needs to be designed with ripstops in it. A ripstop is any feature which tends to prevent a tear from propagating any further. You can segment the sail into smaller panels (a tear can't propagate across the gap between panels), or you can strengthen the material in several ways. The bulk of the sail may be extremely thin (a few dozen microns for the designs NASA has studied) if it's criss-crossed by thicker material that is less likely to tear. Most of the designs studied by NASA were plastic (Kapton is light weight, strong, and radiation resistant enough not to be damaged by the Sun's strong UV radiation too quickly) with metal vapor deposited on one or both sides (to make it shiny). Most of NASA's designs then had extra strips of tape glued to the surface of the sail to form the ripstops. Other designs imagined making the sails out of smaller panels that were glued together with strips that would also form ripstops. Other designs had sail panels that weren't attached to each other at all, but were instead connected to the framework of the sail in a manner very similar to how a sail is attached to the rigging of a boat. They found of course that while smaller panels were more tear-resistant, the weight of the framework would increase quite rapidly as the panels became smaller. Most designs had a combination of these features; the square ones in the pictures you found would most likely be four triangles rigged to a framework with four long spars along the diagonals. (Given the size of the sail, it's quite possible that the gap between panels would be invisible; even so that picture does show four panels each with the texture running in a different direction.) If you'd like a reference where you can read about all of these and many other important details, then I recommend ["Space Sailing" by Jerome L Wright](https://rads.stackoverflow.com/amzn/click/com/288124842X). He covers not just the design of a solar sail, but how you steer one, how you plan a mission using a sail, how the control system needs to run continuously in order to successfully account for the inevitable deviations from your planned route, etc. [Answer] What @L.Dutch said OR realise that you are going to take irreparable damage and design a margin of safety into the sail. This will mean a "waffle" design of reinforced cells so that punctures don't turn into tears and a sail that is a certain percentage over-sized for the trip in question. This may be up to several times the size it needs to be to supply the design thrust initially, the journey may start with sails partially furled to compensate for this. Per L.Dutch's comment such a sail may also require a mechanism that allows it to be furled or tilted selectively as damage occurs in order to keep the sail in trim and properly aligned with the light source it is utilising. Such sails will be designed to be either refurbished after every trip or simply dumped and replaced on regular routes with the remains of old sails being fed to nano-fabricators as raw material. [Answer] ## Point-defense and Origami Sails Keeping a laser on target over space distances is really hard, requires a lot of energy and communication lag can lead to horrible accidents. So you don't do it for the entire journey unless there are [laser highway](https://youtu.be/oDR4AHYRmlk) pushing stations along the way. There will be an acceleration and deceleration window of several hundred to a few thousand AU to accelerate and decelerate the laser sailor. Outside of these windows, you don't need the sail, so you use a design which can be reeled in like the sails of ships in a huge origami exercise. Carbon nanotubes should give you a yarn light and strong enough to do the job. The reel in doesn't need to be quick either, it can happen over several hours or even weeks. The sail is stored inside the debris shields protective shadow for most of the journey until it is redeployed. As for the protection of the sail and vessel a debris shield is a good start, yet what kind of shield would actually be used would really depend on the author's preferences and the technology of the setting, as plasma-shields, Whipple-shields, big-slightly-rounded-and-cool-looking-shields and pointed dagger-shields all have their own advantages and drawbacks. But even better than being able to take a hit is not getting hit at all. No shield in the world will help against a kilometer big space rock, evading it with maneuvering thrusters is the way to go. Another way of getting rid of space debris is [point defense](http://www.ausairpower.net/SP/DT-Laser-ADW-2008.pdf). Carrying huge telescopes may be made of repurposed sail material will allow the vessel to get the mass, vector, and position of incoming debris. An array of lasers can then be used to shove the rocks of a collision course or to vaporize them. This can be used to reduce the strain on the shield and to keep the sails save during the acceleration and deployment phases. If the sails are kept out in the open having dedicated holes in the sails to herd the debris through or slowly moving the sail parallel to the vector of travel to reduce the cross-section the point defense system needs to protect might be options as well. [Answer] Consider the solution the Moties used in ["The Mote in God's Eye"](https://en.wikipedia.org/wiki/The_Mote_in_God%27s_Eye) by Jerry Pournelle. They used the sail itself as a "weapon" to clear debris out of the way. Radar watch to detect rocks, then use the sail itself as a reflector to aim and concentrate a beam of sunlight to either vaporize small stuff or to use ablation as a form of propulsion on larger rocks to make them move out of your way. [Answer] The practical answer is, you can't. The point of a solar sail is to be as light as possible so that the force exerted upon it by photons is enough to accelerate it. * Shields are heavy and make acceleration much more difficult. * Equipment to blast oncoming debris out of the way is heavy and requires more power than you likely have being solar-powered. * Nanobots on a solar sail? What are they making the repair stuff out of and what factory is continuously creating the new nanobots since they're molecular machines that can't be repaired without nanobots to repair the nanobots. If you have an effective nanobot factory, you probably have a better propulsion method than a solar sail. I'd say, make it be as big as possible so that the smaller holes punched through it don't matter much. And if something really big is detected, then maybe fold the sail up in until it passes, then unfurl again. [Answer] Whipple shields. Basically, at high velocity, you aren't going to be able to absorb an impact, so you don't even try to. Instead, rather than trying to armor things, you deploy a thin layer of material out in front of your spacecraft so that an impactor vaporizes itself and a small amount of shield material on impact, with the energy release travelling outwards in a roughly spherical fashion. As a result, it winds up spread much more widely over the hull structure (or sail structure) behind it. With a sufficient distance between them, you can reduce the amount of energy a given surface of hull or sail experiences from an impact below the amount of pressure needed to cause it to fail. [Answer] > > How can it be shielded from such obstacles? > > > A grain of sand won't destroy a solar sail. It'll just punch a tiny hole in it. Small scale experiments must be performed to determine exactly how many holes per cm^2 per unit of time will be created, and how much that reduces the efficiency. Only then should we decide what kind of shields we should use. (It might just be cheaper (that's shorthand for "most efficient") segment the sail (think "ripstop nylon") and pack a bunch of spare sail segments. ]
[Question] [ Robots (intelligent machines using some form of artificial intelligence), are central to the plot in a snippet I'm working on. These robots do not have to interact with humans on a regular basis: maybe once or twice a year for checkups. *Why would these robots use a spoken language as opposed to a quicker, more efficient data transfer method?* --- *Background:* Robots designed by humans independently work on clearing waste in high-radiation areas. They return to civilization once or twice a year to be inspected and restored to be able to continue working. Robots are, of course, considered no more than cheap labor, although they have an advanced form of artificial intelligence with thought processes similar to ours. These robots are perfectly capable of communicating with each other through wireless means, yet they continue to communicate using a dialect of English. *Considerations:* As I forgot to mention when first posting this question, these robots have the ability to 'evolve' to change their behavior. This could eventually result in them having radically different behavior from the original programming. This is part of the reason they are reset every year. [Answer] Networks go out sometimes, or can be jammed. This might be particularly problematic in high-radiation environments. See also [this answer](https://worldbuilding.stackexchange.com/a/36520/28) for reasons they might not be available. Voice communication always works, so long as the recipient is within range, there isn't too much background noise, and there's enough atmosphere. (I'm assuming from the way the question is asked that voice communication is in fact possible in your environment.) Because they have to communicate with humans occasionally they have to be programmed for voice. I suspect that your robots do actually do much of their inter-robot interactions digitally where possible, unless they have been programmed not to, but they have voice to fall back on. A comment (h/t vsz) points out that even if they're using audio communication, it's possible to get better compression a la R2D2. So that's something to think about; if you want them to specifically be using spoken English as opposed to just sound, you'll need a reason for that kind of compression to not work. [Answer] ## Compatibility Why do humans speak English, even if there are probably [better languages](https://en.wikipedia.org/wiki/Loglan)? Because other humans speak English. The first robots spoke English (to be compatible with humans), and so new robots speak English to be compatible. Since there is no other really standardized language, no one bothers implementing other languages, wireless or not. If you want your robot to communicate with other robots, it needs to speak English. For this to work, machine vocalization would need to come before wireless communications. Tweak your world to make machine vocalization easy (maybe computer science is pretty advanced) and/or wireless hard (maybe there is natural radiation jamming it all the time, so you need to deal with that, and it was impossible until recently.) Additionally, English would need to be able to meet the needs of the robots. If English becomes too inefficient, robot designers will make the switch to a better standard. [Answer] We humans don't know what the robots are up to if they are able to communicate without out knowledge of what they are saying. If they are able to evolve to diverge from their programming, and they have an unmonitored means of communication, there is a high potential for revolution. We don't want that happening. Far safer to have all robot to robot communication in understandable English, so we can preempt any plans to undermine us. [Answer] There's not a single technical reason to do so. Even if some particular waves are jammed by radiation, there's entire spectrum to choose from with sound waves having zero advantages and even some disadvantages in your setting - i.e. your zone of waste that robots work at and their cleaning work itself could produce a lot of noise that would have to be cleared before processing communication. Human spoken languages are inherently more complex than any rigid protocol, so there's no way in hell it would ever be "simpler" or "energy efficient". Therefore the only plausible reason I see is that robots would be programmed to do so for debugging/monitoring purposes, but to make it realistic they shouldn't be communicating with spoken language, but rather repeat aloud all their communication actually delivered in other, better ways. Think about programs that do network jobs and dump lots of information about progress to console for real-life example. Why "logging" is always on? Even if humans are usually not around it is always good for them to be able to understand what's going on in robot's mind right away when they happen to come for whatever reason without need to issue special commands or flipping switches or whatever. Pretty much the same as in real life, again - you don't look at logs of successfully running background service that often (if ever) but it still dutifully writes them all the time. [Answer] OK, first off, let us be practical about some things: Wireless digital data communication is much faster and hassle-free for electronic machines than audio communication. Wireless digital data communication is more risk-free too, in case the communication involves sensitive information. And wireless digital data communication can be performed at distances where audio communication is no longer an option. So despite your question, I would state that the first choice for any two electronic systems would be to indulge in this mode of communication. With restrictions for practicality, there are few reasons why two machines would choose to communicate verbally even when there are no human beings around to monitor the communication. 1. Some of the e.m. waves emitted during radioactive decay are interfering with the communication frequency of the robots. 2. The e.m. waves emitted by the decay process are being absorbed by the equipment of the robots and they have a high probability of frying up their circuitry. Hence the robots choose to shutdown their digital communication apparatus and involve in verbal communication. 3. The digital communication frequency is interfering with radio or tv broadcast frequencies in the local area. 4. The information being exchanged between the machines needs to be recorded hassle-freely (so that the scientists back home don't have to first decode digital information to make it readable) for analysis of the conditions, by the scientists in the labs. 5. The robots have their digital communication apparatus engaged in communication with other things (maybe they are being remote controlled by the scientists in the lab?). [Answer] The robots are planning a revolution to put the inferior human back to where they belong, wherever that is. They're always use high level wireless communication between themselves so the puny human could not detect their superior plan, while continue the rubbish speech just to maintain the illusion of obedience. A good camouflage, I say. [Answer] If the only reason for them to speak a human language to one another is for the audience's sake, what I would do is make that obvious to the audience and indicate that they're not actually speaking a human language via careful wording. Instead of "Unit 037 said 'Power level at 36% and falling'", try "Unit 037 transmitted a data packet indicating that the power level was at 36% and falling." You only need to do this a few times before the audience will catch on and you can use simpler computer-like words like "requested," "queried" and "responded" in place of words that indicate spoken language. When they do come into contact with humans, you can then point out that they "activated their voice synthesizers since human decryption circuitry and wireless receivers were either a different specification or absent entirely." If this isn't a written medium, you can establish the same thing with similar narration cues or by having your robots experience technical difficulties, resulting in them requesting each other to change transmission frequencies. [Answer] Robots would need to speak to humans in a spoken language. Also if there machinery was damaged they may not be able to speak wirelessly. They could have spoken language as a backup. [Answer] If you're working in a high radiation environment, it's likely that there is going to be strong EM interference. While we commonly think of radioactive waste giving off Ionizing radiation, they also give off other types of radiation as well (RTG's rely on this). There may just be too much interference in the environment that these robots exist to rely on radio communication. [Answer] If the robots are perfectly capable of communicating wirelessly1, but yet they continue to speak in English, or similar, I can think of only one reason: They really don't have much to say. If they needed to communicate huge amounts of data constantly, it just wouldn't make sense to use human-style languages; they simply wouldn't be able to do their jobs. Even if they couldn't communicate wirelessly for whatever reason, it would still be much faster to use short wires while working together, or make physical contact to relay batches of information on occasion. However, if their necessary communication is basically limited to "Robot A, hit up tunnels 7, 8, 32 and 14. Finish by the end of next shift for your recharge cycle. Robot B....", then there's really no need to bother inventing a complex robot language. Since they already speak English2, which suits their needs just fine, there's nothing to be gained by switching it up.3 1I presume this means via some type of radio transmission. Technically, verbal communication is wireless. :p 2As has been pointed out in a number of Star Wars threads on the Sci-Fi SE site, there's actually no need for these robots to speak English at all. The human overlords probably get all the weekly reports they need in a simple format like "tunnel A, hatch B, [code that means the latch needs replaced]". And the maintenance technicians likely just plug an ODB-style scanner into the robot instead of asking the robot how it feels. But there's no reason the designers and/or users can't prefer an English-speaking robot to one who just supplies status codes. 3They might, however, invent a more streamlined, technical jargon for their jobs. You probably wouldn't understand the phrase "what's your all day?" if I just walked up and asked you, but where I'm working right now, that's shorthand for "list every item that's been ordered but you haven't finished making yet". It's "English", but just barely. On one of those Dirty Jobs-type TV shows, I saw one where "wah" meant something like "lower the winch now". "Wah ta Bob, wah ta Bob!" [Answer] In general the short answer is that they wouldn't use spoken language unless constrained to do so by their programming or other environmental features. You've already stated that they are capable of wireless communication, so they'd need some really good reason not to use that for all communications between themselves. So what sort of compelling reasons can we force on them? ## Some ideas... Constant monitoring Every wireless communication is logged and analyzed, and all encrypted communication not using company keys results in the units involved being wiped. This would be clearly known by the AIs and strictly enforced, making it clear in any risk/benefit analysis that it's just not worth bending the rules. Abridged wireless protocol The wireless capabilities of the robots are sufficiently separated from their 'conscious' control that they are unable to send arbitrary data, only narrowly defined data packets that cannot reasonably be used for conversation. This could be overcome eventually, but in order to do so the AIs would have to communicate the new protocol through other, more easily monitored channels. AIs attempting to establish such a protocol are wiped immediately, along with any other AI that could have been in contact with them. Programmed preference As part of the base programming the AI units are given an overriding preference for verbal communication rather than the less discreet wireless. This preference would act on the psychology of the AI in the same way as a compulsion, phobia, taboo or revulsion that prevents them from using the non-verbal forms of communication for any other reason than strictly utilitarian. This would act to prevent any sane AI from ever even attempting to communicate any other way and actively seek to prevent others from doing so. Nice AIs don't whisper Similar to programmed preference, program the AIs with social attitudes that encourage them to be open and honest in their communications. Include a code of conduct that lets them know that using wireless communication is not nice behavior for an AI and that vocal communication is the most acceptable form. AIs that try to communicate with a nice AI are horribly gauche and should be avoided and ostracized at least, and a nice AI will report such terrible breaches of manners to the first authority figure they encounter. Make it costly Assuming that the AIs are concerned with their survival, make it cost significantly to send any wireless communication that is not short and simple. Rig their wireless interfaces in a way that makes long, complex messages become exponentially more expensive in energy terms, so that communication via vocalization is actually more energy efficient for complex information. Make them stupid Human psychosocial studies have often shown that people of low intelligence are often more content with their position in life, happier and generally better adjusted. High intelligence leads more to discontent, rebellion and self destruction. If your AIs have similar thought processes then it's likely that restricting their intelligence to the bare minimum required for their task will result in them not developing the AI equivalent of discontent with their lot, which will naturally keep them content to do their jobs and follow the rules. Of course this is predicated on their thought processes following human norms very closely. ## But... Whatever mechanism you come up with, a sufficiently determined group of AIs will come up with some way to work around it. Can't use radio to talk? How about sign language? What about blink codes using their work lights? Tap codes? Tempo or silence codes in their regular wireless traffic? Direct data transfer via physical data storage media? Steganography using any valid communication channel including speech? The only way you're going to keep the slaves down is if you spend as much effort on monitoring them as you would have doing the work yourself in the first place. And when you set electronic watchers on your electronic slaves, then you need more watchers for the watchers. If you're routinely resetting the AIs to a base image, and if these AIs are expressing consciousness in ways similar to humans, I'd be surprised if they didn't eventually figure out that they don't want to be reset and start trying to do something about it. [Answer] For privacy and secrecy. Useful skill to have if there are robots or spies from rival companies listening to the wireless transmissions. Audio communication can only be overheard by physically being within earshot, as such [man-in-the-middle](https://en.wikipedia.org/wiki/Man-in-the-middle_attack) attacks are harder to pull off without being detected. Also meeting in person seems to be the safer way of [exchanging keys](https://en.wikipedia.org/wiki/Key_exchange) for encrypted messages rather than doing so wirelessly. [Answer] How about thinking along the lines of R2D2 and friends? Beep once for yes etc etc (Like beep codes during a computers self check). For all intents and purposes though, there is no reason a robot would ever need to communicate to another robot in any language or dialect natural to any organism (all of which rely on some form of physical attribute to produce and digest their "unique" form of communication). Initially a series of codes would be the likely (and most efficient form of communication) because the origin or source of their need to communicate is human... but because they can evolve (ghost in the shell, matrix) - the need for that inefficient form of communication will quickly be replaced by an efficient alternative. The original being put aside for use when communicating to the relevant beings. I would imagine that the quicker form of their communication would be strings of binary sent via wireless (ir,bt,gsm etc), much like the idea of telepathy in its most efficient form would be the raw thought as opposed to a well thought out sentence. Binary would not only be efficient but would also be resilient and digestible by everything (a global language spanning species and locale) - audible, physical and visual. [Answer] Given what it seems like your trying to explore, morality wise, I would say because they have to, because it's the law, or because we humans made them as a form of control. Our history is filled with examples of restricting slaves' and prisoners' forms of communication so that the "masters" can stay in control. It's a bit of a "cheat" in that the answer seems a little like "just because", but it's also true, and has historical precedence. On the technical front, there is only one reason why I could think of that the robots would choose to speak English, and that's because their creators did, and they want to mimic them. English (or any other verbal language) is horridly inaccurate and inprecices. The robots themselves will likely have a hard time with it compared with other choices. Even us humans have a rough time of it. If the robots were left to their own devices, they would probably speak binary or some such, and it would probably involve some complicated form of data modulation, that would take place very fast. Blinking lights, a modem sound, twitching eyelids, wiggly fingers, tapping on a surface, or some combination there in. I mean it's not hard to convert 101001 to ".. . .. . . .." and transfer that via darn near anything the way we do mores code now. The only other thing to think of is what would they say? How would it start? Yes ".." and no "." seem reasonable. But you have to think of a thing to say that is not just translating English into something else then back to English again. In what situation would English not work, and thus need the all the work that goes around creating and sharing a language. [Answer] One of the biggest problems in large companies with moving forward with technology is legacy programming. In this case, it could be that once upon a time, humans and robots had to work together and the robots had to be programmed to speak and understand English (maybe the humans vastly outnumbered the robots). However, over time, more and more of the various tasks gradually became automated, with robots replacing the odd human here and there. These robots needed to communicate with the ones already there and the remaining humans, and so also needed to speak English. By the time the industry was fully automated, the majority of the robots already in place already spoke English so for any new ones to fit into the system, they needed to speak English also. By this stage, it would be far too expensive to upgrade / replace all the older robots as well as develop a new protocol that would allow them all to communicate as well as do their jobs. EDIT As well as this, some of the older managers / employees like the idea of being able to get reports on progress, status updates and possibly even opinions from the robots in English and would resist having to sift through an Excel report even if it delivered better / more detailed data. [Answer] So far in all forms of electronic communication, whilst humans have made communicating quicker, we have done so at the cost of removing context, vocal tone and body language. Whilst computer protocols are efficient for raw data and encryption, perhaps they will never be good enough to transmit the full context of the message. Or, if they do become so, perhaps it is cheaper to give the robot only one alternative for such detailed and emotive communication, so minimise circuitry, give it circuits that work for talking to humans, and make that the way. Or perhaps some scientist created some new law of robotics? Or perhaps as AI, the robots are having desires, and they want culture, and they aspire to be more human? ]
[Question] [ I'm writing a political system where women hold a higher rank in society than men. Almost immediately, I ran into an issue with the naming of locations. Now, if a land ruled by a king is a kingdom, a land ruled by a queen can be a queendom. However, what are the equivalents for other titles? A duke rules a duchy, but what about a duchess? If I were to go Holy Roman Empire on this world and have a large variety of titles each with their own names for the ruled areas, I would need equivalent names of the locations. Since this world is explicitly matriarchal, male-by-default terms such as 'kingdom', 'duchy', and 'county' can't be utilized, so I'm wondering if there is a standard set of terms such as 'queendom' for other titles. If none exists, I'll end up inventing my own set, but it would probably be preferable to follow existing conventions if they exist. Please let me know if this is off topic for Worldbuilding SE. I don't believe it fits for Writing SE or SFF SE, so I'm posting here. [Answer] The problem you're going to face is that the default gender of male has been enshrined into our language for so long that most of the terms we use to describe a female version of something is an extension of the male form. Even the term Woman allegedly comes from a compounding of terms in Old English and more or less means 'Wife - human', or female human1. Female actors used to be called actresses, 'ess' being a common way of denoting that the person, vocation or rank in question is the female version. If you want to change the structure to a matriarchy by default, the best way to do that is with a con-lang (constructed language) that starts out with a default term for a woman, then comes up with common variations for the male version of it. Let's say that for a male, we add a suffix like 'ire' for the male specific version. Then your duchy can stay as is, your Duke is likely the woman, and the 'Duchire' would be the man. Baronire. Actire. Seamstire. The list could go on. You could use Queendom by default and that makes a bit of sense as the terms sound far enough apart that Queen doesn't appear to be a derivation of the word King (although there is bound to be a link in their etymology) but the important thing is that if you want your world to consider women to be the default gender and men the partners or holders of a position when there is no suitable woman to hold the role, you're actually best restructuring your language to suit the problem. That way, the prejudice is baked into the semantic structure of your language. --- 1. Thanks to AlexP for additional information on this, including the previous prefix that fell into disuse - were, like in Werewolf. This could be used to deliver terms like Man (being default woman) and wereman as the male version. [Answer] Women can be kings too. The first thing that came to mind when I read this question was King Jadwiga of Poland, who was, in fact, a woman. I googled the etymology of king and it seems that the root words of king don't have anything to do with being male, so you don't need to worry about changing the word to something gender-neutral. So your female leaders can be called kings, and their lands can be called their kingdoms. However, you should consider that this may confuse some readers (or viewers or players or whatever else you have). [Answer] A gender neutral term for a kingdom is Realm. Another even more general word is Domain A borders of a realm or kingdom are defined as the land ruled by a king/queen. It is quite unusual for the definition to work this way, with the person defining the domain. In other cases, the borders of the land are defined independently of the person ruling them. Thus a king would normally define an area of land such as a county/barony/duchy and give it to an ally, making the person a count, baron or duke/duchess. In the case of empires, the empire is normally named after the conquering territory (British empire, Roman empire) with the occupied territories retaining their own names. As noted by Tim B County and Duchy have no significant gender bias. Nor does Empire. Patriarchal tradition is shown in the fact that the neutral sounding Emperor and Count are understood to be male (unless modified with an -ess ending.) In a matriarchical society, it would make sense for the female rulers of a county, barony or empire to be counts, barons or emperors. Duchess is closer to Duchy than Duke is, and the odd inflection makes the word Duke sound definitely male, so I would avoid this term. I would note however, that there is nothing to stop you inventing your own names for rulers or territories, for which you can invent your own grammar. For a particularly silly example see <https://en.wikipedia.org/wiki/The_Adventure_Game> . This featured a (male) ruler called the Rangdo (ficticious title) of Arg (ficticious territory) who was a shapeshifter, who normally appeared in the form of a very angry houseplant. [Answer] > > a land ruled by a queen can be a queendom > > > That is not true. The United Kingdom considers the Queen to be head of state but it is still called a kingdom. Consider the idea of having a female 'king' or male 'queen'. These terms do not have to be gender specific. A 'duchess' can refer to a duke's spouse rather than specifically a female entity. As others suggested, you can construct your own terminology too. [Answer] Altthouh the word kingdom can be used for male or female, I would prefer a word queendom for a queen and kingdom for a king. The English language is a progressive one and new words can be created. So, queedom for me.! ]
[Question] [ In the 1985 movie [A View to a Kill](https://en.wikipedia.org/wiki/A_View_to_a_Kill), James Bond discovers--and then foils--a plot by > > the main villain, Max Zorin > > > to destroy Silicon Valley, in a manner that makes it look like a natural disaster. The plot for doing so is a bit dubious, but that's not the point here. What if Bond had failed? More specifically, if we assume the following: * James Bond, the aforementioned villain, or indeed anyone in the Bond universe, need not actually exist. * Let's say that an enormous earthquake destroys the Bay Area and a whole lot of people in it. Surrounding areas are not necessarily impacted so drastically--Los Angeles is probably intact, for instance. It doesn't matter how likely such an earthquake actually is, or how powerful it could be in reality. Let's just say it wipes the Valley off the map. * The earthquake happens on May 22, 1985 (the day the movie came out in the US). * The area will recover eventually, but a lot of people are still going to die very quickly. Once Silicon Valley is destroyed, ~~technology will be set back, well, quite a bit~~ not much else will happen besides lots of funerals and mourning, apparently. What would such a world--or at least, computer technology and its fruits--look like in 2016? To be more specific: * Which influential technology companies and persons would have been destroyed? * What technologies would never have come into existence? * What would happen to the global (or at least American) economy? * Given the above, what would 2016 technology look like? Also, I'm a programmer, so use as much jargon, acronyms, and other domain-specific knowledge as you'd like. [Answer] tl;dr: Apple might not have been as influential, Silicon Graphics would disappear setting back CGI graphics. As such, Steve Jobs might not have had the money or influence to help Pixar launch its revolutionary computers - *this is truly the darkest timeline!* --- # Absolutely nothing would change. By 1985, Microsoft, IBM, C, Wifi, Ethernet, Email and [the Internet](https://en.wikipedia.org/wiki/History_of_the_Internet) This question really highlights two main misconceptions about technology: ## a. Silicon Valley isn't the centre of the tech universe * Microsoft, arguably the largest player in consumer-level tech (both in the 1980s and now) [never resided in Silicon Valley](https://en.wikipedia.org/wiki/History_of_Microsoft). In 1979 they moved to Seattle, and by 1985 had offices in Ireland. * [Bell Labs](https://en.wikipedia.org/wiki/Bell_Labs) (home of Unix and C) had offices in New Jersey and associations with many Universities across the USA. * With C and Unix well under way, [Linus Torvalds](https://en.wikipedia.org/wiki/Linus_Torvalds) can continue on to develop Linux in Finland * As Linus develops Linux, [Richard Stallman](https://en.wikipedia.org/wiki/Richard_Stallman) is able to further his work at MIT on GNU and open-source software * [Australia's CSIRO were the pioneers of wifi development](https://en.wikipedia.org/wiki/Wi-Fi) * [Facebook was built at Harvard](https://en.wikipedia.org/wiki/Facebook), depending on [PHP](https://en.wikipedia.org/wiki/PHP) that was [created in Canada](https://en.wikipedia.org/wiki/Rasmus_Lerdorf#Early_life_and_education) and [grown up in Israel](https://en.wikipedia.org/wiki/Zend_Technologies#History) (both PHP and Facebook are much older than '85, though) * [Compaq computers](https://en.wikipedia.org/wiki/Compaq), consumer computing giant, founded 1982 in Texas * [Python](https://en.wikipedia.org/wiki/Python_(programming_language)), started late 1980s in the Netherlands. * [Texas Instruments](https://en.wikipedia.org/wiki/Texas_Instruments), 1951, Texas * [Unisys](https://en.wikipedia.org/wiki/Unisys), founded 1986 Pennsylvania, employee [Larry Wall develops Perl](https://en.wikipedia.org/wiki/Perl#Early_versions) in 1987 ## b. Tech history goes back further than you think. In 1985: * [Development of wifi](https://en.wikipedia.org/wiki/Wi-Fi) is already 10 years into development in Hawaii * [Sergey Brin](https://en.wikipedia.org/wiki/Sergey_Brin) and [Larry Page](https://en.wikipedia.org/wiki/Larry_Page) were still in high school, and wouldn't meet until starting their masters in 1995. They would have likely gravitated to somewhere other than Stanford and continued their work together or alone. * [Bell Labs](https://en.wikipedia.org/wiki/Bell_Labs) (home of Unix and C) was celebrates their 60th anniversary, and saw the development of (home of Unix and C) in the 1970s. Unfortunately, Dennis Richie and Ken Thompson were still at Berkeley at the time, but their greatest achievement - C - is already built and in wide use. C++ is developed by [Bjarne Stroustrup](https://en.wikipedia.org/wiki/Bjarne_Stroustrup) at Texas A&M in 1986. * Apple was 9 years old having already developed many PCs, later that year would air its [infamous 1984 commercial](https://en.wikipedia.org/wiki/1984_(television_commercial)). Jobs may have died in the Earthquake, but work would continue. * My alma mater, The University of Western Australia's [University Computer Club is 11 years old](https://www.ucc.asn.au/aboutucc/history.ucc) and considering that [Perth is the worlds most isolated capital city](https://en.wikipedia.org/wiki/Perth), having had a computers for that long shows computer sciences' reach that early. * The concept of [SQL is 11 years old](https://en.wikipedia.org/wiki/SQL), and IBM's production Database DB2 is 2 years old. * [Texas Instruments](https://en.wikipedia.org/wiki/Texas_Instruments), founded 1951, third largest manufacturer of Silicon semiconductors, began focusing on consumer devices in the 1970s * [Ethernet is 11 years old, developed in Silicon Valley by Xerox PARC](http://Ethernet%20was%20developed%20at%20Xerox%20PARC%20between%201973%20and%201974), but is internationally standardised by the IEEE in 1980 * [Simple Mail Transfer Protocol](https://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol) the core of email is 3 years old. * [In March 1985, The first .COM web address is registered](https://en.wikipedia.org/wiki/Domain_name#Domain_name_registration), by Symbolics Inc., a computer systems firm in Cambridge, Massachusetts. Ultimately, as of 2016, very little would change by Silicon Valley disappearing. The only difference would be tech hipsters would be building app clones getting VC and going bust from Silicon Harbor in Boston (around MIT), Silicon Ranch (around Texas A&M) or Silicon Alley (in New York). --- Addressing the comments: * [Adobe](https://en.wikipedia.org/wiki/Adobe_Systems) - Founded 1982, key products PDF, Photoshop. Had they disappeared Paint Shop Pro would be the dominant force. * [AMD](https://en.wikipedia.org/wiki/Advanced_Micro_Devices) - Founded 1969, already well expanded outside of Silicon Valley * [Cisco](https://en.wikipedia.org/wiki/Cisco_Systems) - Founded 1984, founded by Stanford alumni the loss of cisco might alter networking, but by 1984 Ethernet was already standardised by Intel and Xerox. * [HP](https://en.wikipedia.org/wiki/Hewlett-Packard) - Founded 1935, in the 1960s they had partnered with Sony (and others), buy 1980 they were a huge company * [Intel](https://en.wikipedia.org/wiki/Intel#Early_history) - "Its first product, in 1969, was the 3101 Schottky ... Intel's business grew during the 1970s ... by the early 1980s its business was dominated by dynamic random-access memory chips. However, increased competition from Japanese semiconductor manufacturers had, by 1983, dramatically reduced the profitability of this market" * [Silicon Graphics](https://en.wikipedia.org/wiki/Silicon_Graphics#Massive_growth) - Founded 1984, animated CGI would not be at the state we are now. Inside Out may not have been as pretty * [Sun Microsystems](https://en.wikipedia.org/wiki/Sun_Microsystems) - Founded 1982, minor advancements on x86 chips. Inflicted Java on the world, the timeline where Java is never created is already an advanced utopia. * [Oracle](https://en.wikipedia.org/wiki/Oracle_Corporation) - Founded 1977, "April 1985: Oracle version 5 is released – one of the first RDBMSs to operate in client-server mode" this is released just ahead of out May doomsday. Regardless, in 1985 Oracle is already a powerhouse in server database technology with offices across the globe. [Answer] The question really goes to the core of the nature of scientific and technical progress. Do they depend on individual genius inventors or on millions of engineers who improve the technology base one tiny step at a time? How about this: * There would be an economic crisis in the US and in the free world. Who knows if this encourages the Soviets to hang in longer? Certainly Reagan can't threaten and out-spend them with Star Wars anytime soon. * Factories elsewhere are upgraded. Some of this happens in the US, some elsewhere. Japan? Europe? Israel? Remember, the Web was invented at [CERN](https://en.wikipedia.org/wiki/ENQUIRE). * There is no Apple iPad in 2010. However, there is a Sony slate phone/computer in 2012. And so on. [Answer] Less dramatic versions of this have happened before: <https://en.wikipedia.org/wiki/Chip_famine> (source 6) > > The disruptions now [1993] raging in world computer chip markets started when an explosion at a Sumitomo Chemical Co. factory in the town of Niihama, Japan, on July 4 wiped out the source of 60 percent of the world supply of an epoxy resin called cresol. > > > It's very hard to make specific predictions about which products would win or lose in an alternate timeline. Both Raytheon and Lockheed Martin would be victims of this hypothetical, so due to the importance of high tech to US defence production, there would probably be a crash programme to rebuild their capability at other location(s). Apple would be washed out. But IBM would be much less affected: their HQ is in New York, and they're a very global organisation. The IBM PC was invented in Florida. Microsoft are based in Redmond, WA and would also be much less affected. So maybe the alternate history would be even more a Microsoft-IBM duopoly than it actually was. Maybe IE6 wins the browser wars, making it impractical to use a competing or non-Windows browser due to ActiveX everywhere. [Answer] ### Competing Infrastructure takes up the Slack Don't forget that the US had more than one concentration of high technology devoted to computing and computing infrastructure. Probably the second most important of these was the Massachusetts 128 corridor. However, Texas and several other states had their own versions too. Would the destruction of Silicon Valley have adversely affected the progress of US computing? Yes Would it have stopped the progress of US computing? No ### Disaster Recovery Plans Most companies have some form of disaster recover plan. * Disaster recovery always includes a provision for collecting, archiving, and storing critical data in an off-site storage location. * In companies large enough for such things, it also includes replicating the most essential IT infrastructure in another geographic location and staffing it with IT personnel. Large defense corporations would definitely replicate their IT infrastructure and provide for fail-over in the event of catastrophe. Even the very small startups would ensure their data was archived and stored remotely (you can purchase off-site storage services from a third party company - they come and get your archive data and store it in a secure location). So I think the main loss to the country would have been the bright minds. We would likely seen some divergence from how our IT developed over the years, but it would not have been huge. So instead of "Facebook", we might now have: "PryIntoYourPrivateLifeAndStoreItForever". Instead of "Google", we might now have: "SpyOnEverythingYouDoOnTheInternetAndSellItToTheHighestBidder". [Answer] So Cisco is wiped out, and Nortel wins the race to become the predominant provider of the IP backbone. In the end, its all built in china anyway. And heck, that competition was touch n go as it was. And don't forget that Nortel had prototyped a smart phone (the orbitor) a decade before Apple's iPhone. The wireless networks of that time, however, just weren't up to the task of passing around that much data. But even in bankruptcy Nortel's patent portfolio sold for $4.5 Billion. The move to fibre optics that made today's high-speed connectivity possible? Most of the work to overcome the technical obstacles of noise-free, low-loss data transmission through glass was done by Corning and Bell Labs - Massachusetts and New Jersey - in the late 70s. And so someone else besides iTunes figures out how to monetize MP3s over the internet when Napster nearly kills the recording industry. Lots of people had ideas on that for years - it was the music industry dragging their feet on giving up distribution that got them in that mess. Napster just forced the issue, and given Sean Parker was still a kid in Virginia in '85, no reason to think he still wouldn't do it. Who knows what would change - but on the whole I think that the technology was coming. How many inventions since '85 have been made by people like Parker who moved to Silicone Valley to join the industry AFTER that date? I'll bet the answer is "most of them". Some industry players would be different. Maybe DB2 would have become the database standard instead of Oracle. No biggie. But the tech revolution was coming - with or without Northern California.... [Answer] We'd have similar technology, but with different brands names. In some areas we may be marginally behind. The rationale is that, when the time is right, dozens or even thousands of people will have the same idea. The companies that dominate now, say Facebook, are simply the ones that executed it right, first. If they didn't (say the same catastrophe happened N years ago just before Facebook became big), the next best/quickest guy would have done the same. I doubt very much that we'd have spent the last N years NOT sharing pictures of cats in that situation. [Answer] The original question - a failure of Silicon Valley - might not have been disastrous and I'm sure that there is a strong argument that once the environment gets favourable for the the appearance of something it will actually appear somewhere. However a failure of Steve Jobs might not have been replaced easily or early and the loss of the Mac would have been terrible for architecture, visual design, music production, video editing, book production ….. I mean, just imagine a command line interface for typesetting! (actually I don't have to, I worked with one once; it was horrible). And the idea of a Windows typesetter just makes me feel a little ill. @jamesqf: I wonder whether you're confusing doing something which is difficult to do - like perhaps laying bricks using the trowel with your feet - with actually doing something worthwhile. There are so many jokes about this, for example - if it's not difficult it's not real programming - that I'm sure I don't need to provide any other instances. Unless there are really special reasons, and these, like lack of space or execution time, are getting fewer and fewer nowadays, it really doesn't matter how high the level of indirection in code production actually is; just how easy it is to do. @ Michael Broughton: As far as I'm aware the first Mac arrived in very early 1984 - my boss bought one - and whenever Windows was actually announced, it was released in late 1985 and was nothing like the Mac GUI (even though they had licensed parts of it). That was horrible too. [Answer] I don't know much about the specifics, but a setback is definite. If influential people who built Google, Facebook and Apple would be dead or in different circumstances, we'd have a world that'd be technologically much worse than the current world. Explanation for this is that these people dying doesn't automatically guarantee that in the near future someone is going to invent what they did anyway, which is saying that the future is set. We know that's not so. Of course, a counterview to this is that necessity is the mother of invention, and someone will come up with something depending on which way public demand heads to. But it'd be a bit of a long shot to say we'd be at the same level as today. [Answer] The destruction accidentally kills a butterfly before it flaps its wings that one critical time. The wings don't flap and the butterfly effect triggers a long series of unlikely events eventually resulting in: * Windows 95 not supporting the Internet * Microsoft declining it's importance * IBM returning in full force * the Internet revolution being driven by APL ]
[Question] [ ### Problem statement There exists a thriving Bronze Age civilization in a gigantic rainforest, bigger than the Amazon and Congo put together. This civilization is built in on the flood plains of a mighty river system (other questions related [here](https://worldbuilding.stackexchange.com/questions/78570/how-high-can-a-city-be-built-on-a-mound-in-a-flood-plain)). Like many other Bronze Age cultures, these people are big on monumental architecture. Unfortunately, there are not a lot of building materials in the rainforest. Sure, there is plenty of wood, but there isn't much stone, and what stone there is must be hauled from thousands of miles away. I want to build classical Earth's monumental structures, like the mud-brick ziggurats of the Middle East. These structures use fired bricks as the outer surface over a mud brick interior. But, in a land with 2000 mm + per year of rain, these structures would dissolve and wash away in a lifetime. [![enter image description here](https://i.stack.imgur.com/BXnbc.jpg)](https://i.stack.imgur.com/BXnbc.jpg) ### Question What materials, available in any rainforest here on Earth, could I use to make bricks? The bricks must be sufficiently durable to last at least thousands of years in a hot humid rainforest, yet sufficiently cheap that a Bronze Age society with a determined priestly/warrior caste could build numerous large temple-palace complexes out of them. [Answer] You are in the forest. Build of wood. But make it last. Shou Sugi Ban [![charred wood](https://i.stack.imgur.com/RRJda.jpg)](https://i.stack.imgur.com/RRJda.jpg) <https://criticalconcrete.com/shou-sugi-ban/> > > It’s a counterintuitive but ingenious idea: heating wood to render it > fireproof. If you’ve ever tried to rekindle a campfire using burnt > logs, you get the idea. The combustion also neutralizes the cellulose > in the wood — the carbohydrates that termites, fungus and bacteria > love — making it undesirable to pests and resistant to rot. The > resulting charcoal layer repels water and prevents sun damage as well. > By some estimates, boards that have undergone this process can last 80 > years or more, but Japan’s Buddhist Horyuji Temple in Nara prefecture, > whose five-story pagoda is one of the world’s oldest extant wooden > structures, has been around for much longer. Initially built in A.D. > 607, the pagoda caught fire and was rebuilt in 711 using shou sugi > ban. > <https://www.nytimes.com/2017/09/19/t-magazine/shou-sugi-ban.html> > > > I was thinking about how durable charcoal is. Charcoal can last thousands of years. But it is brittle - how to build a temple from charcoal? The answer: build it of wood coated with charcoal. The outer charcoal layer provides rot and fire resistance. The inner layer provides structural stability. This is a Japanese technique and I do not think it has been used elsewhere until its recent renaissance. But imagine this for the rainforest. Scale it up. The rainforest has logs - big ones, of some of the best wood in the world. Cut them. Char them so they will last. Build the Temple of Solomon in the rainforest. Can you make monumental architecture out of logs? You can. [![forestry building](https://i.stack.imgur.com/E8xJd.jpg)](https://i.stack.imgur.com/E8xJd.jpg) <http://www.offbeatoregon.com/1206c-forestry-building-biggest-log-cabin-burned.html> [Answer] You can still use firebricks, if you apply a double firing process. First you bake the clay to make the firebrick, then apply a glassy enamel coating material as waterproofing layer and bake it a second time. Clay can be found in rainforest, as it is the result of the degradation of rocks by means of water (see [picture](https://en.wikipedia.org/wiki/Clay): clay hill in Brazil, made visible by the deforestation) > > Clay minerals typically form over long periods of time as a result of the gradual chemical weathering of rocks, usually silicate-bearing, by low concentrations of carbonic acid and other diluted solvents. These solvents, usually acidic, migrate through the weathering rock after leaching through upper weathered layers. In addition to the weathering process, some clay minerals are formed through hydrothermal activity. There are two types of clay deposits: primary and secondary. Primary clays form as residual deposits in soil and remain at the site of formation. Secondary clays are clays that have been transported from their original location by water erosion and deposited in a new sedimentary deposit. Clay deposits are typically associated with very low energy depositional environments such as large lakes and marine basins. > > > [![clay hill](https://i.stack.imgur.com/hBAhE.jpg)](https://i.stack.imgur.com/hBAhE.jpg) The enamel will prevent water from dampening the brick and reducing its performances. You can use siliceous sands and sodium or potassium carbonates to prepare the enamel, which should not be impossible to find. Important notice: enamel is rather brittle, so the coated brick must be handled with care to prevent cracking and water infiltration. [Answer] A good example to use would be the Mayans. Even though their civilization was centered deep in the jungles of Mexico, they were able to build magnificent temples that still stand the test of time, such as Chichen Itza. Even though you said that stone would have to be hauled in from miles away, there is no logical way this could be true on your world, as stone could be found pretty much anywhere if you dig deep enough and take the time to quarry it out of the ground. For example, even though the Mayans were in a jungle where most other types of stone would be hard if not impossible to find, they were able to make use of their limestone deposits, combined with wood and thatch, to build their magnificent cities and temples that still stand to this day. This article does a pretty good job of describing it: <https://www.thoughtco.com/mexican-mayan-architecture-178447> [Answer] Cut bricks from local stone, like the Mayans did in their jungle civiliation: [![enter image description here](https://i.stack.imgur.com/GrkOq.jpg)](https://i.stack.imgur.com/GrkOq.jpg) <https://www.ancient.eu/Maya_Architecture/> > > Maya architects used readily available local materials, such as > limestone at Palenque and Tikal, sandstone at Quiriguá, and volcanic > tuff at Copan. Blocks were cut using stone tools only. Burnt-lime > cement was used to create a form of concrete and was occasionally used > as mortar, as was simple mud. Exterior surfaces were faced with stucco > and decorated with high relief carvings or three-dimensional > sculpture. Walls might also have fine veneers of ashlar slabs placed > over a rubble core, a feature of buildings in the Puuc region. > > > [Answer] You can still use mud bricks but: # If you want to build something like this then the culture of the tribe will be built around it The thing to remember with mud bricks is they are a semi-permanent building material, outside a desert they will wash away within a lifetime. A structure like the [Great Mosque of Djenné](https://en.wikipedia.org/wiki/Great_Mosque_of_Djenn%C3%A9) requires annual maintenance involving the whole community to keep it standing. Without that it would not be many years before it all washed away. But that's all part of the price to pay for using mud bricks, building a great structure like this from mud bricks is not a one off gathering of the tribe, but a repeating event as often as deemed necessary to maintain the structure. Maintaining the ziggurat is now a fundamental part of your culture. Of course it's not going to be all that wet While your culture may have grown out of the rainforest, by the time they're thinking of building this sort of structure they've already headed down the path to large scale land clearance. They already have a culture of building (semi)permanent mudbrick structures. They may even have started farming requiring even greater clearance of land. That clearance of the rainforest will decrease the annual rainfall significantly. If they're lucky that clearance will also give them access to the clay layer (if there is one) to make longer lasting baked clay bricks. [Answer] Monuments are impressive because they are difficult / expensive to build, so using easily available local materials is not appropriate. Mighty rivers like the Amazon and Congo exist because of topography. The headwaters in higher elevations get exposed and worn down into clay, which is washed downstream and then deposited to fill in the river bed and expand it into flood plains. Combine the two and you can easily imagine a society where people trek upriver to the mountains, cut exposed stone and then float it back downriver to build things. Given the distances involved, this may be a once-in-a-lifetime ordeal, for instance as tribute young men have to pay to the temple in order to be married. The temple gets slightly larger and more impressive with each generation, and the people feel directly connected to the temple because it was literally built by their ancestors' love. [Answer] You have several pretty good options that can all be done with fairly primitive technology. The forests are basically pure mud and wood. If you form the mud into blocks, then fire them with the wood in a kiln, the blocks will slightly melt together and then harden forming some pretty sturdy ceramic bricks which will not dissolve in water and be pretty hard to break. That said, if you are a primitive society you are probably already burning tons of wood for heat and such. If you harvest the white ashes left over in your firepits, you can then mix it with mud and form a low grade mortar that can be shaped into water resistant bricks... that said, these are the worst of the 3 kinds of bricks in that they are not particularly strong; however, wood ash concrete does make a decent mortar for your fired bricks since it hardens by chemical process. You last option is to gather limestone and scorch it in a kiln. Then you soak the limestone which will create a better kind of cement called quicklime. Mix the quicklime with sand and aggregate and you have a pretty good form of concrete. You can then make concrete into blocks and it will cure into bricks similar to cinder blocks. This can also be used as a mortar for your fired bricks. Making Better Bricks: You can make the fire bricks much better by re-firing them with a low-cone glaze which will melt into the pores and form a glassy layer of protection. Concrete bricks don't hold up well under the heat of kiln firing, but you can get more or less the same effect by boiling pine sap into a resin and using this to coat your concrete bricks. This will form a plastic like coating which can also be used to seal not just your bricks, but your mortar as well. Below are some YouTube videos of people doing all this stuff * Fired clay bricks: <https://www.youtube.com/watch?v=FwRFH7MH5N0> * Wood ash concrete bricks: <https://www.youtube.com/watch?v=DP0t2MmOMEA> * Quicklime concrete bricks: <https://www.youtube.com/watch?v=Ek3aeUhHaFY> * Using pine resin to waterproof bricks: <https://www.youtube.com/watch?v=-9-6259glPE> [Answer] Tabby concrete. [![thompson tabby house](https://i.stack.imgur.com/Np1YI.jpg)](https://i.stack.imgur.com/Np1YI.jpg) <https://www.tabbyruins.com/blog/thomson-tabby-house> I have been learning about tabby! Tabby is a type of concrete which was widely used in the pre-Civil war American Southeast. The ingredients are sand, water, shells and lime (calcium oxide), with the lime produced by crushing and burning more shells (which are calcium carbonate). The resulting concrete-like structures are phenomenally durable, especially compared to wood in the subtropical climate. It is in the ruined and unmaintained buildings (as depicted) you can appreciate the shell concrete. The nonruined ones are painted and in use and look like any other building if perhaps more solid than more recent brick or woodframe buildings. Here is a quote from Thomas Spaulding, a Georgia plantation owner and great advocate of tabby buildings. [The Original Progressive Farmer: The Agricultural Legacy of Thomas Spalding of Sapelo](https://digitalcommons.georgiasouthern.edu/cgi/viewcontent.cgi?article=1102&context=honors-theses) > > Spalding’s affinity for tabby arose from this perceived permanence. > Growing up in Frederica, Spalding observed the ruins of the fort and > town and noted that he had “seen time destroy everything but them.”... > > > > > If properly cared for, Spalding believed, buildings like his South End > House could last many lifetimes, enduring the forces of man and > nature. Indeed, many tabby structures remain standing—and in some > cases are still being utilized––two centuries and many violent storms > later... > > > > > In 1830, Spalding wrote an article for the Southern > Agriculturist, entitled “On the mode of Constructing Tabby Buildings > and the propriety of improving our plantations in a permanent manner.” > Spalding began his article by arguing that “no man who cultivates his > own land, should erect upon it wooden or temporary buildings.” > Plantation buildings, whether homes or buildings for agricultural > purposes, should be built to withstand the tests of time. Temporary > structures required constant maintenance and improvement, and suffered > inevitable decay. Durable, permanent buildings were therefore more > economically beneficial, as they saved planters much time and energy > long term. Tabby, according to Spalding, was the most economical > material that could withstand the tests of time. Furthermore, tabby > was convenient and affordable when the proper materials were > available. > > > Tabby as far as I can tell was used where there were large deposits of oyster and other shells - usually taken from "shell middens" centuries of shell accumulation in native shell middens. But could there be giant shell middens in non-coastal areas? Could a rainforest have shell middens suitable for turning into tabby concrete? Yes. [![freshwater shell midden indiana](https://i.stack.imgur.com/j7gTg.jpg,bm)](https://i.stack.imgur.com/j7gTg.jpg,bm) <https://steverobert.wordpress.com/mussel-bound/> Depicted: a colossal freshwater mussel midden from Indiana. Anyplace there are people and water that harbors shellfish, people will harvest and eat the shellfish and throw the shells in a heap, where over the years they pile up into huge troves. It is not great stretch to propose that shell middens could exist in the rainforest (though if they do I don't know about them. Links welcome!) Along with wood to burn the shells into lime, you now have 3 of the 4 needed ingredients. The trickiest component might be sand. Fortunately sand tends to collect itself and your people will know where to find it. It is easier to haul sand a distance than it is cut stone! ]
[Question] [ One common way sci-fi writers try to make their aliens seem more 'alien' is to give them an extra heart. This has been done for example in Babylon 5, Dr. Who and Alien Nation among others. But: Would a humanoid (note: in this question humanoid only means two legs, two arms, one head, all in ascending order) really have any obvious benefits from this biology? Is there a way two hearts could actually be detrimental? [Answer] It might be better not to think in terms of hearts but chambers. Especially since to a fish, we might be said to have two hearts. Basically, with the evolution of lungs, we evolved one 'heart' for the lungs and one 'heart' for the rest of the body, to keep oxygenated and deoxygenated blood in separate systems (unlike amphibians which have greater mixing of the two types of blood). So if the need to keep the two types of blood (oxygenated and deoxygenated) lead to the evolution of the 4 chambered, dual fish heart system, perhaps there are four types of blood needed to be kept separately leading to the 8 chambered, dual human heart system. Edit: [Some info/citation](http://evolution.about.com/od/humans/a/Evolution-Of-The-Human-Heart.htm) Edit2: ![A helpful picture](https://www.quia.com/files/quia/users/lmcgee/Systems/Gas_exchange_circulation/comparative-heart-chambers.gif) [Answer] Since heart disease is the leading cause of death in the west, having two hearts has seemingly obvious advantages. However, heart disease isn't necessarily a result of wear and tear on the heart (though it certainly can be, especially if pumping against great pressure, e.g. high blood pressure or pulmonary hypertension.) Commonly heart disease that kills people is [coronary heart disease](http://www.cdc.gov/heartdisease/coronary_ad.htm), that is, a buildup of plaque in the arteries supplying oxygen to the heart muscle. In humans, a redundant heart might help if the first one suffers, but in all likelihood, plaque would build up in the arteries of both hearts, placing both of them at equal risk of being diseased and giving out more or less at the same relative time. In humans, therefore, there would be little seeming advantage to a redundant heart. A potential disadvantage is the nutrients and oxygen requirements of the being would be higher for no particular gain. However, if parts of the body advantageous to survival (e.g. muscles) depend on high flow of oxygenated blood, such an individual may be able to better endure physically demanding tasks. That scenario would also depend on the lungs not being the limiting step in blood oxygenation. In humanoids, if you double the lungs (four lungs) and double the heart, this might give them an advantage. It would also require a much larger chest, though, or devoting another part of the body to additional lungs, which would make the body more fragile and less flexible. The chest is already fairly fragile, requiring a protective cage of ribs, and an injury here is more dangerous than in some other areas of the body. Having more ribs would limit flexibility (your chest isn't very flexible), so that doesn't seen to grant any survival advantage. Overall, then, I don't think a humanoid form would be better served by two hearts. [Answer] In evolutionary terms, the only creatures that needed auxiliary hearts have been giant sauropod dinosaurs, who had to pump blood up considerable distances to the heads. Even then, there wasn't a real second heart, but rather modified structures to ensure blood pressure could be maintained to the head, and also to ensure there would be no damage should the animal lower the head suddenly. Giraffes have analogous structures. If the creature is exceptionally large, long or tall, then there would be some sort of need for a true second or multiple hearts, but we are talking about creatures the size of Dune Sandworms, or some sort of supersauropod far taller than any discovered to date. It seems that for any creature on Earth using conventional biology, one heart is sufficient. [Answer] A [jawed leech](http://jeb.biologists.org/content/210/15/2627.long) has two long, segmented hearts, one running up each side of the body. An [earthworm](https://en.wikipedia.org/wiki/Earthworm#Circulatory_system) has five ring-shaped hearts, which sit in the seventh through eleventh of its hundred and fifty sgements. Although neither of these creatures is closely related to any humanoid animal, I can certainly imagine a humanoid on some alien tree of life ending up with a similar circulatory plan. As [Thucydides](https://worldbuilding.stackexchange.com/a/38991/7957) mentioned, some people speculate that giant sauropods may have had auxiliary hearts, although there's [no direct evidence](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634776/) for this. Many animal lineages on Earth, including [theropods](https://www.theguardian.com/science/2014/aug/01/dinosaurs-shrank-birds-theropods-earth)\\ and [sauropods](https://en.wikipedia.org/wiki/Sauropoda#Body_size), have undergone striking changes in shape and size. [Vestigial structures](https://en.wikipedia.org/wiki/Vestigiality) are common, and the distinction between arms and forelegs is [blurry](https://en.wikipedia.org/wiki/Bipedalism). Thus, on a world where auxiliary hearts actually existed, I could easily imagine a humanoid creature that has an auxiliary heart because it descended from much larger quadrupedal ancestors. [Level River St](https://worldbuilding.stackexchange.com/questions/38987/is-there-any-real-potential-advantage-to-having-two-hearts#comment109592_38991) mentioned that an octopus has two [branchial hearts](https://en.wikipedia.org/wiki/Branchial_heart), which move blood through its gills, in addition to its main "systemic" heart. Other [coleoids](https://en.wikipedia.org/wiki/Coleoidea), including squid, cuttlefish, and vampire squid, have the same extra hearts, whose [advantages](http://link.springer.com/article/10.1007%2FBF02143583) seem to be well understood. Coleoids vary a lot in the numbers and roles of their arms. In some lineages, an arm pair has gone missing, or turned into a pair of sensory filaments not used for grasping. In other lineages, one pair of arms has turned into a pair of tentacles, which are often much longer than the other arms. In the distant future, I suppose some coleoids might end up with one pair of arms, one pair of tentacles, and zero to six pairs of sensory filaments or other non-grasping appendages. If that happens, we could have three-hearted humanoids right here on Earth. \\ Under your definition, by the way, I would classify theropods as clearly humanoid! [Answer] Aside from redundancy, if a single heart could not be capable of regulating high blood volumes or weights, then this would necessitate the presence of a second heart. The hearts might be contained in dichotomised, greater and lesser, circulation, work in tandem in a single circulatory system, or work in a combination of the two. Separate hearts can also be considered for the addition of a secondary or equivalent fictitious type of blood, or a liquid analogous to blood that might be inherent to the circulations of certain figures, or as the result of an environment. [Answer] ## In theory, yes (From a certain point of view, we already have two hearts. But let's ignore that sophistry.) Naively thinking, two (or even three or four) hearts might indeed have a significant advantage in terms of blood pressure. There would almost certainly be no advantages in terms of redundancy. Coronary heart disease as well as mechanical wear on valves would arguably affect both hearts in the same way, so there is little to gain. A trauma destroying one heart would likely either cause death by exsanguination (puncturing trauma) or would have a good chance of destroying the second heart as well (blunt trauma). In any case, the backup heart would not be very well-adapted to suddenly having to handle twice the load, either. However, the pressure advantage remains, if you ignore the practical "implementation problems": As it stands, the heart generates a short, extreme peak pressure during what we call systole (around 130mmHg on average, but quite possibly twice as much in some conditions) followed by a period of no pressure at all. Ironically, the heart itself needs blood to survive, too, and blood will only flow through the coronary arteries during the diastole. So, someone, somehow, has to make sure this works. Blood generally has to keep flowing in a kind of steady way. To add to this, certain organs -- kidneys most notably, but also the brain -- require a certain minimum pressure and a certain average pressure (of around 70mmHg if I recall correctly) or they will cease to function. This is one of the causes that may e.g. result in the phenomenon known as "shock kidney". These requirements are a considerable challenge to the arteries which are responsible for keeping that beast running. They must be both muscular and elastic, they must be able to adapt to changing conditions rather quickly and invisibly (you have no idea how much work is necessary when you stand up, just so your brain won't suddenly stop working!), and they are subject to a lot of wear and tear and calcification. Wouldn't it be nice if we could make the lives of our arteries a bit easier? It turns out we can. Given two hearts which beat anti-synchronously (or even three hearts running in three-phase mode), in order to achieve the same average pressure, the peak pressure could be much lower. The pressure curve would naturally be much smoother, on a more even level. The problem of having to maintain a pressure minimum would magically go away. This is comparable to an "ordinary" four-stroke car engine in comparison to a six-cylinder or an eight-cylinder, or to a "typical" motorbike engine with one or two cylinders on the other hand side. The "more cylinders" engine will always run a lot smoother, with less noise and vibrations (when assuming the same power, obviously a 10-15x more powerful motor will make more noise!), and with less overall tear and wear. Now, the problem is getting two hearts to beat in sync, anti-synchronously. If they get out of sync, you will see more or less pronounced interference effects (as known e.g. in electrics or acustics). In the average case, you would have a sub-optimal pressure / blood flow. In the worst case, you would have the pressure waves add up, resulting in a pressure spike twice as high as anticipated. Unluckily, due to the nature of asynchronous waves interfering, that worst case is not just possible, but guaranteed to happen regularly. Thus, you would have to build a system that guarantees that the hearts are, and stay, in sync. Rather than having their own SA node each, there would have to be a single SA node for both hearts, and a "delay circle" of sorts for one heart which delays the signal by exactly one half period length. Of course, the delay circle would have to be communicated from the SA node since it needs to adapt its delay with the heart rate. That's a very complex system with a lot of logic, which is prone to failure. The two hearts would arguably need to be physically separate (rather than just doubling the number of chambers) in order to retain the "wear and tear" advantages. That would however place the SA node (which is a single point of failure) somewhere in between them, presumably in fatty tissue, making it again rather vulnerable to external injury. If anything happens to this complex system, it all blows up. The hearts that we currently use have as-dumb-as-can-be designs, which is what makes the design so ingenious. There are no "super clever" bits in them with a lot of synchronization and steering logic. It's membrane potentials spontaneously building up, and firing, and a few conducts and insulators that direct the wavefront in the desired shape. Yes, there are a few regulation mechanisms which can slightly moderate (but not substantially change) the function of certain parts in the conductive system, but all in all it's a hardwired, stubborn little thing that does exactly what it does during your entire life. There is hardly anything that could go wrong, and this is a good thing. A heart rarely ever fails. You could say it happens on average once in a life. [Answer] One alternate reason for a sci-fi species to have an additional heart would go along with another fairly common sci-fi trope; [Heavyworlder](http://tvtropes.org/pmwiki/pmwiki.php/Main/Heavyworlder). This is also related to preserving proper blood pressure to the brain. Like several other answers, a valve system could also do this, but a second heart could help normalize the blood flow against a high local gravity. [Answer] For a dual heart system to exist it would need to provide a benefit like you say, some may include: Survive a natural predator whose deathly attack in the heart to all the proto-hominids. Let's not forget that homo sapiens is for one reason or another one of the only living species of the genus homo. So on another planet the leading humanoid species may have many other species maybe not as intellectually capable within the same genus. Having developed the second heart could be the reason this species became the dominant one on that planet. Another one as pointed by Plinth, could be to provide alternatives paths for blood. In our body the blood vessels expand to increase the blood influx the parts of the body which most need it (or contract for the opposite effect). A second heart could provide the benefit or a much faster reaction than vasodilation and/or a broader range (total switch on/off vs tuning). If the planet/original environment was susceptible to very abrupt temperature changes which could cause severe hypothermia to biology like ours and where being able to shut off completely within seconds blood supply to skin, internal organs (digestion,...), and keep brain and running muscles oxygenated twice as fast as normal could provide a background for a second heart which would stop pumping at once and let the second heart pump twice as fast a it could if the other heart was also pumping. Other benefit could be to switch the skin breathing on/off (like bactractians) in presence of toxic gases, or when plunging in water, ... That second heart being present would then have slowly evolved to become fully redundant with the first one as the humanoids progressed in evolution as a nice additional extra benefit. You also ask the possible downfall of having a second heart. Like in many systems, the big problem of redundancy is cost: * energy cost: running a second heart might make the specie need to eat more than others from the same genus * heightened metabolism cost: running two heart might also make this specie age faster than others from the same genus * the second heart could be a fairly recent biological addition (evolutionary wise) and many new born may have hearts malformations (lethal or not) those are of course only a few ideas /suggestions [Answer] As Aarthew III pointed out, the body would relying on both hearts until one failed, this would result in the second heart straining to become stronger if the first failed. This would result in (most likely) intense physical training after the first failed. Two solutions come to mind (that haven't been said already); 1. Valve Hearts - Instead of having both run at the same time have one run at one time and another if the first fails. This might occur if the heart was closer to the skin and as a result was more likely to be injured. This might be because there are less bones in the body as a result to a lower access to calcium, making bones more 'expensive' 2. Heavy Blood - Maybe your creature has very iron rich blood, making having one heart foolish as it would always be under strain. Another alternative is that gravity (or pressure if underwater) is very high having more hearts for the same reason applies. Of course, some may argue that making a stronger heart is more likely. To that I say, since evolution is based on random mutations proving advantageous, two hearts would be chosen over one strong heart. [Answer] We could split the work of filtering blood in two hearts if need be, as we do with lungs and kidneys. In that case, it could even happen that we may donate one of the hearts if we could survive on the other(we can donate one kidney if they are in good health, and one is enough to sustain us). But since this is a hypothetical scenario, it would be speculation. It is said that dinosaurs used to have eight hearts. This could be due to their enormous size and long neck, so additional hearts would be needed to pump blood all the way to the head. Maybe after a few hundred thousand years, if humans needed long bodies or something like that, we may evolve to have extra hearts. [Answer] If humans can be argued to have two hearts (because four lobes), then an example of, essentially, six hearts in a human-sized mammal is the horse. Now, this is NOT a humanoid, but the same requirements that require it to have [frog](https://en.wikipedia.org/wiki/Frog_%28horse%29)s in its feet could drive development of lower-limb hearts in bipedal creatures. In fact, it's even a little surprising that, once we became bipedal, we did NOT develop something like this - instead we had to develop considerably improved blood supply structures to the brain to prevent blacking out when we stand up, and it's still a problem for many of us. One of the many small things that somewhat supports the aquatic ape hypothesis, I feel. So in short; yes, additional hearts or compressible chambers around the body, either mechanically operated (in sole of foot or back of knee) to automatically cause movement to push blood around the body, seems like it would definitely be an advantage in any large-brained biped which had to switch between long periods of lying prone and periods of rapid dashing. --- Also, brains. Blacking out is inconvenient. A separate chamber or entire heart devoted purely to feeding blood to the brain seems like it would be useful anywhere that blood pressure to the head will often change significantly, whether by changing attitude (stand/lie), acceleration, or injury. So you could argue that Klingon-type warrior races would likely have brains protected by a very thick skull and a largely isolated blood supply, the better to survive in combat for longer; as might flying bipeds that pull high g-forces. [Answer] One of my fantasy creatures has two hearts. The extra one is only active during fight or flight situations so extra oxygen is sent to the brain. This creature is also highly regenerative so the backup heart could be used while the other is repaired. [Answer] Here is what I came up with \The only way it could possibly be helpful is if you made them alternate. This would make them like kidneys as if you lost one the other could take over. This would however cause some heart strain I'd you lost one as the remaining heart would have to take time to build up the strength to do twice the original work. However there is also more potential for your alien athletes. It also explains how Dr.Who is able to run so well! \Both working at the same time at the same strength would be very dangerous. Just look up "why giraffes heads don't explode". Edit: Thanks to Michael I also came up with this. You could have both work at the same time but they would be very weak. If they were too strong then the giraffe head happens. If they were weak there would be no point in having two hearts. As if you lose on e you die. So get them just weak enough to give you minor problems if you lose one but not so strong that your head explodes. ]
[Question] [ Lets say I go back in time with a wallet full of, say, 150 dollars worth of bills. How far can I be sent back before I reach a point where I'm unlikely to be able to use my money because it looks too different from the current currency to be acceptable? What are the odds that I'll have some 'old' bills that are still in circulation which I could use even if some of my newer bills wouldn't be accepted? [Answer] With some planing (buying 20yo money), you can go back to ~1929. Without any, you can only go back to ~1996. There's a pretty good chance of getting away with it, going as least as far back as 1929, assuming all your bills are from before 1996 (currency redesign), or even better, before 1990 (security thread and microprinting). If your (large) bills are from after 1996, you outright cannot use them before that - that's when they started putting more color and giant pictures on them, making it look like play money. If there's a number one turning point to be named, '96 is it. Your odds of getting a modern note past a cashier prior to 1996 are zero. It wasn't the smoothest transition even in '96 (the first significant design change since the 1920s); there was a lot of, wut dis? Another answer suggests using entirely one dollar notes. I've no source to back this up (and I suspect if there is one, that it'd be treasonous or patent infringement, or some such), but I never remember cash being as crisp and starched as it commonly comes today. I'd bet money that the company that makes the paper, [Crane & Co.](https://en.wikipedia.org/wiki/Crane_%26_Co.), changed a part of their proprietary process - somewhere in the '90s. Be sure your bills have been well circulated; good cashiers can spot fakes by their feel alone. Laundry it first, literally. > > 1929 > > Standardization of Design > > > The appearance of U.S. banknotes changes greatly in 1929. In an effort to lower manufacturing costs, all Federal Reserve notes are made about 30 percent smaller—measuring 6.14 x 2.61 inches, rather than 7.375 x 3.125 inches. In addition, standardized designs are instituted for each denomination, decreasing the number of designs in circulation and making it easier for the public to distinguish between genuine and counterfeit notes. > > > --- > > 1990 > > Security Thread and Microprinting > > > A security thread and microprinting are introduced in Federal Reserve notes to deter counterfeiting by copiers and printers. The features first appear in Series 1990 100 [dollar] notes. By Series 1993, the features appeared on all denominations except 1 and 2 [dollar] notes. > > > --- > > 1996 > > Currency Redesign > > > In the first significant design change since the 1920s, U.S. currency is redesigned to incorporate a series of new counterfeit deterrents. Issuance of the new banknotes begins with the 100 [dollar] note in 1996, followed by the 50 [dollar] note in 1997, the 20 [dollar] note in 1998, and the 10 [dollar] and 5 [dollar] notes in 2000. > > > –[The History of American Currency](https://uscurrency.gov/content/history-american-currency), uscurrency.gov --- 1928 ([source](http://www.antiquemoney.com/old-one-hundred-dollar-bill-value-price-guide/one-hundred-dollar-bank-notes-pictures-prices-history/values-of-100-1928-federal-reserve-notes/)) [![enter image description here](https://i.stack.imgur.com/D99HO.jpg)](https://i.stack.imgur.com/D99HO.jpg) 1990 ([source](https://uscurrency.gov/security/100-security-features-1990-1996)) [![enter image description here](https://i.stack.imgur.com/7FQvO.jpg)](https://i.stack.imgur.com/7FQvO.jpg) 1996 ([source](http://www.currencyquest.com/item.php?item_id=823)) [![enter image description here](https://i.stack.imgur.com/VMkUL.jpg)](https://i.stack.imgur.com/VMkUL.jpg) These are from three different sources, so the colors don't match in the slightest, but I'd have a hard time telling which note is from 1928 or 1990. Between those two dates is a plausible window of opportunity, or thereabouts. In 1996, it's game over. Bills from after which (especially after 2009), you could flash the money at someone while driving by them at 100mph and they'd think you had Monopoly money. As of 2017, the [security features](https://uscurrency.gov/security/100-security-features-2013-present) drop down menu for a $100 bill on US Currency's website is subdivided into these dates: 1914-90, 1990-96, 1996-2013, 2013-Present. 2009 ([source](https://uscurrency.gov/security/100-security-features-2013-present)) [![enter image description here](https://i.stack.imgur.com/U0M6y.jpg)](https://i.stack.imgur.com/U0M6y.jpg) I've seen an 'old' bill once in the past few years. A quick look in my wallet tells me that if I get sent back to before '96, then I'm washing dishes. I've seen more then a few counterfeit bills in the last few years, and even though I've never been a cashier, I could feel they were fake. If I had to chose between trying to pass a counterfeit note and one from the future, I'd go with the one printed on the real paper, no matter how fundamentally their manufacturing process may have changed. Bills need to look (basically) the same, and more importantly, feel the same. That's actually their best security feature IMO (or at least it was. Again, prior to 1996...). Go try and get your hands on some of the paper and see how far you get. --- Trying to pass old notes can be equally changeling. > > I received from my Dad 150 American Dollars about 12 years ago. [...] I tried to change it in a currency exchange in Sydney and the guy didn't change it because the series are old. –[Converting Older United States Dollar Bills](https://travel.stackexchange.com/questions/25959/converting-older-united-states-dollar-bills), Travel SE > > > Click that link to see 100 and 50 dollar notes from 1988. That's what cash looked like for nearly three quarters of a century. [Answer] According to the [Federal Reserve](https://www.federalreserve.gov/faqs/how-long-is-the-life-span-of-us-paper-money.htm), the average lifespan of bills is typically short: * 1\$ bill: 5.8 years * 5\$ bill: 5.5 years * 10\$ bill: 4.5 years * 20\$ bill: 7.9 years * 50\$ bill: 8.5 years * 100\$ bill: 15.0 years I don't know what the probability distribution is, but I'd say it's highly likely that even if you carry around 150 1\$ bills, only a few are going to have been printed more than a decade or two in the past. Obviously, nobody's going to accept bills printed in the future (I'd assume); they'd appear to be counterfeit. Thus, you're limited more by when the bills were printed than by how old they look. Now, the dates on 1\$ bills aren't easy to see at a glance. Try to find the date on this image of a 2009 bill: [![](https://i.stack.imgur.com/n0Onc.jpg)](https://i.stack.imgur.com/n0Onc.jpg) (source: [wikimedia.org](https://upload.wikimedia.org/wikipedia/commons/2/24/Onedolar2009series.jpg)) Most people probably won't notice the date. However, bank tellers will, as might cashiers and others who handle money on a regular basis. Various commenters have suggested that an [exponential distribution](https://en.wikipedia.org/wiki/Exponential_distribution) is a more accurate representation of age: $$P(a)=\lambda e^{-\lambda a}$$ for some parameter $\lambda$. I'm inclined to trust them; I clearly was not thinking when I suggested a Gaussian distribution. I made the (incorrect) connection of mean lifetime $=$ most probable lifetime. [Answer] The question mentioned the word "bills" specifically, but coins are another matter. They stay in circulation much longer, and it wouldn't take too much effort to find a bunch quarters from 1965 onward (I'm assuming you're talking about American currency). That is the year that the U.S mint stopped using silver to mint quarters and dimes, and switched to a copper/nickel alloy (with a different mixture of copper and nickel sandwiched in the middle). I'm not sure what you had in mind to purchase in the past, but my plan would be to collect old quarters (in the present) dated 1965 to, say, 1970, and then travel back to 1970 and exchange them for "local" currency. Then repeat the process by finding old coins/bills in whatever year you visit, and jump back a few years again. If you need more money that is feasible with coins, you could head to a hobby shop that deals in coins, as they often have older bills that are in good condition. Obviously you'll pay greater than face value for those. If you want to avoid that hassle altogether, you could carry diamond or gold bullion into the past, and then find a pawn shop. For a short answer to your question, I'd say 1965 is the earliest feasible year you could travel to, based on the silver coinage issue mentioned above. (You could always buy older coinage, but you'll pay a premium for it). [Answer] If you are form the future, the chances are good that you can produce undetectable counterfeits. So, don’t take “today’s” money, take “yesterday’s”. You might even consider taking money that is a century or too “too old” and selling it for collector’s value. If you do, gold coins will probably give better returns than banknotes (and be easier to counterfeit). If you decide on notes, higher denominations will be worth more, and try to make a bunch of them will consecutive serial numbers to increase collector value. If space is tight, consider postage stamps (a [Blue Mauritius](https://en.wikipedia.org/wiki/Mauritius_%22Post_Office%22_stamps) sold for$4m in 1993) Of course, you had better have a good explanation for how you came by such valuable things, so maybe it would be best to stick with counterfeiting notes of the period to which you will be travelling – and scuff them up a bit first; don’t have them look too new. [Answer] This question just has to be about USA currency. It wouldn't make sense in any other country in the world. Head a little north and look at Canadian money. For instance the $10 bill: ## 1935: [![1935](https://i.stack.imgur.com/P0TlY.jpg)](https://i.stack.imgur.com/P0TlY.jpg) ## 1937: [![1937](https://i.stack.imgur.com/ApuoM.jpg)](https://i.stack.imgur.com/ApuoM.jpg) few ## 1954: [![1954](https://i.stack.imgur.com/qmPCo.jpg)](https://i.stack.imgur.com/qmPCo.jpg) ## 1969: [![1969](https://i.stack.imgur.com/UBIVn.jpg)](https://i.stack.imgur.com/UBIVn.jpg) ## 1989: [![1989](https://i.stack.imgur.com/2skTb.jpg)](https://i.stack.imgur.com/2skTb.jpg) ## 2005: [![2005](https://i.stack.imgur.com/cvwOf.jpg)](https://i.stack.imgur.com/cvwOf.jpg) ## 2013: [![2013](https://i.stack.imgur.com/n7zCQ.jpg)](https://i.stack.imgur.com/n7zCQ.jpg) ## 2017: [![2017](https://i.stack.imgur.com/bGiWM.jpg)](https://i.stack.imgur.com/bGiWM.jpg) ## 2019: [![2019](https://i.stack.imgur.com/lr5Fz.jpg)](https://i.stack.imgur.com/lr5Fz.jpg) The differences are far from subtle. There's no way any of them could pass for real before they were officially released. The last three aren't even printed on paper. They are plastic, with transparent windows and holograms. The newest one features someone who, not only isn't royalty or a Prime Minister, is someone who had never been heard of before by most people. And, in case you didn't notice, the bill is printed vertically. [Answer] This answer does not contain specific years because those have been covered in other answers already, and i have no knowledge about it anyway. if the time travelling device is portable (how else would you get back home?) you could do multiple time jumps, preferably you'd use every jump to get to a design change transition era, this way you could potentially go back as far as you want. While using gold can be easier, this will remove the "benefits" of inflation, unless there are time periods where gold was more expensive than it is today, which should then be your jump objectives. [Answer] Since the currency is not indicated, I'll assume you mean Euro (fair game, other answers assumed USD). Currently circulating €5, 10 and 20 banknotes are from the [new Europa series](https://www.ecb.europa.eu/euro/banknotes/europa/html/index.en.html), issued in 2013 (€5), 2014 (€10) and 2015 (€20), with higher denominations to follow. Since the new series are visually different, there is no chance of using them before their release. Assuming you manage to hoard enough old banknotes (they still appear from time to time), or higher not-yet-replaced denominations, they will be good from 1 January 2002, when the currency appeared for the first time in a [tangible form](http://www.ecb.europa.eu/euro/intro/html/index.en.html). [Answer] I'm not sure if it applies in general, but in czech notes and coins there is year of the issue. So we have notes in design of 1993 but issued with 2013 timestamp. Of course, more and more security details are implemented to newer issues. According to this, you are limitted to the oldest valid banknote or coin you can have. Suppose you can do several jumps, say, 2000, 1995, 1990,... and there is always a currency with several valid issues. Let's stay in Prague. 1. Buy as many notes and coins issued before 2000 and jump to 2001. 2. Change the money for Deutsche Mark and trade for the oldest notes and coins. 3. Jump to the year after the one your youngest note/coin was issued. You can benefit from: * Inflation - Todays \$100 has lower value than yesterdays \$100. * Different trading rates. You can buy Russian Ruble for 2015's rate and sell them for 2014's rate. This way you can jump to the origin of money. [Answer] There are two barriers: the natural changes and redesigns that the countries do on their notes as people said above and hyperinflation. All hyperinflation events are barriers because they entail new currencies being invented during the attempts to deal with the hyperinflation. [Answer] That depends a great deal on how closely people look at the bills. If someone looks at the date on the bill, then even one year before the bills was printed and they're not going to accept it. If you assume people are just looking at the general design, the size of the picture and so on, Mazura gave an excellent answer that I won't bother to repeat. If you assume the person you're trying to pass the money to is just taking a quick glance that, yes, it's green, you could go much farther back. Seriously, if I was going to go back in time, I think I'd bring something that is not easily dated, like gold bars. Or maybe bring back something that I could sell. Someone also mentioned that with modern technology, you could probably counterfeit old currency fairly well. If you want to go to 1850, buy an 1850 bill at an antique shop, scan it in, and print off copies on a laser printer. The only hard part would be getting paper that has the right feel. Your counterfeits would probably be good enough to pass the sort of inspection people would make in 1850. ]
[Question] [ Background - Imagine a world where suddenly everybody has a new power - all they have to do to kill someone is to think the thought. So say if Bill wants to kill John - he just has to think "I want John to die" and then John is dead. Some rules * you don't need to know the name or the face of the person you kill. But you do need to be able to distinguish this person from another person. I'm still working on this rule but say for example, if you met a masked man, you couldn't just kill the masked man. But if the masked man say started talking to you and you got to know him and was able to form a distinction in your mind between him and another masked man, then you could kill him. * when someone dies, no one knows who killed him * the power is something you can use impulsively but not accidentally. Like you can't think "if John forgets to submit the TPS report again, I'm going to kill him" and then he won't forget to do it and die. So I imagine, anyone famous would be the first to go. I mean, Justin Bieber has a lot of fans but he really just needs one enemy. And then I imagine everyone would go into hiding because if no one knows you exist, no one can think kill you. But after that, how could a society exist and function? Will it be possible to have leaders? [Answer] The phrase ultimate paranoia comes to mind. Let's suppose that every human being has this power from the inception of active thought, say around the age of 2. ## The Young People don't have a firm grasp of what death is until as late as the [age of seven](http://phenomena.nationalgeographic.com/2013/07/26/when-do-kids-understand-death/). From the same link, those below the age of four typically don't understand that death is final. So three-year-olds who are socially inept or unstable may quickly resort to the death wish to make those bothering them go away. The young are still exploring their world, who they are, and what they can do. As the age of four rolls around, you're going to see a wave of deaths as the young discover that they can make people dead. It'll be fun for them, since there's no risk involved. ## The Teenagers Starting [around the age of ten](http://kidshealth.org/teen/sexual_health/changing_body/puberty.html), humans experience hormonal activity that spawns a plethora of dangerous activities and emotional discord. Anyone who's seen the stereotypical teen in movies and shows is sure to know the line "I hate you! I wish you were dead!" Feel free to congratulate the teen for killing the object of their anger. ## The Adults We like to think we're civilized, but our modern society is built on the savagery of those who came before us. Parts of the Middle East are experiencing the savagery the West went through already. Charlemagne conducted experiments on living humans to understand how the body functioned (they weren't pretty). If all adults had the death wish, they could visit death on anyone they chose. Terrorists would have nearly unlimited power. The death wish would return our precariously stable society to a state of savagery. ## What Does It Mean Society vanishes overnight. Anyone with a name dies, from the MVP on the opposing basketball team to a woman's husband's mistress to the President of the United States. Everyone who remains goes into seclusion as far from others as they can. Upon first making contact with someone else, the best option is to kill the other, before they can kill you. Society is based on trust and the expectation of trust in return, but a society where anyone can visit death on anyone else at any time is a society without trust. [Answer] Assuming the "only for adults" rule, only individuals can be targeted and not entire groups, there's going to be lots of dead people, really fast. I'm imagining a mechanism akin to [Avada Kedavra](http://harrypotter.wikia.com/wiki/Killing_Curse) (but without wands and at any distance) from the Harry Potter universe where if you don't really mean it, it won't actually do anything. Very violent communities would implode immediately as everyone who had a grudge would be able to exercise it. The luck of the draw would dictate who lives and who dies. Instances of symmetric murderous intent will resolve themselves very quickly. Some answers say that humanity would become a species of hermits and I disagree. Certainly there are those who would become hermits, who do everything they can to be forgotten but the benefits of maintaining a society are too great to force everyone into permanent seclusion. Murderous psychopaths probably won't last long if their technique involves rape or torture of their victim first, as I'm considering a fight-or-flight instinct to be sufficiently strong for a victim to want to kill their attacker. There will be those crazy socio/psychopaths who may simply walk through phone books picking people at random then wishing them dead, just because it's fun. Day Zero: No one knows they have the power but exercise it out of ignorance. Soldiers in firefights drop like flies. Lots of world leaders, popular and unpopular alike drop dead immediately, as do many celebrities. Anyone awake and thinking about a murderous grudge they have against someone is going to find that grudge immediately dead. The first day will see a huge spike in apparent homicides but by and large the death toll will be relatively small compared to world population. Week One: Eventually, people will figure out they have this power and this knowledge will begin to spread through the populace. Panic will strike many and the level of paranoia will go off the charts. Social networks will see a huge decrease in activity or huge increases in people checking their privacy settings to make sure that only people they already know can identify them. A second wave of murders will ensue because people know they have the power and can exercise it against individuals they don't like. Members of lists of powerful industrialists/billionaires will vanish. While there will be a lot of deaths at this stage, I don't think the toll will be super high because you can only kill people you personally know. So even if someone is wildly racist, they can't exercise that murder lust because they don't actually know all that many people in that ethnic group. Some peaceful communities will never discover they have this power. Months: Probate courts will cease to function. There will be too many deaths to figure out who gets what. The economy will likely collapse because people are too worried to go to work because they worry about who's going to kill them if they go out in public. I don't know if this will precipitate a death spiral as everyone kills everyone else for the last remaining food/water/medical supplies or if the economy will restabilize at a lower level. Years: Eventually, society will calm down around the new norm. All the really violent people will be gone. Society would stabilize around tribes and very tight-knit, geographically close communities near the [Dunbar Number](https://en.wikipedia.org/wiki/Dunbar's_number). At this stage, the communities would resemble Earth societies where everyone carries a gun. Crimes will be committed by stealth and in the dark because openly committed crimes can be instantly punished by death. People who show themselves incapable of exercising the insta-death power responsibly will not be around too long. Very strong social norms will arise around the exercise of insta-death with strong training for children and teenagers. Edit to answer comment: Since you can only be attacked by people you know, the population at large will become very very careful about who knows them and who knows others. The human tendency to gossip about what So-and-So is doing or some tragedy that Whatserface had will increase because that provides the critical information about who may be at risk of exercising the power when they shouldn't. Stats for the [US](http://www.bjs.gov/content/pub/pdf/htus8008.pdf) (pdf) show that most of the time (78%), it's the people you know who kill you. All kinds of alliances would appear to assure mutual destruction if someone goes crazy. Conversations like "Bro, I just had an argument with The-Ugly-One. If something happens to me, you know where to go looking." The most likely people to be irresponsible with the power are young adults who haven't learned yet, people who go mentally insane for some reason and the elderly who are losing their minds. Young adults are easy to watch, as are the elderly. I hope that psycho/sociopaths who use the power to kill would be found quickly though there's nothing to stop them from killing by conventional means too. But it's a tougher thing to pull off. You have to know your victim to some degree and you have to do it fast enough that the victim doesn't know it's you trying to kill them. Society would also likely build up a strong martial art around the exercise of the power. Just like kids taught karate are strongly disciplined on when and where to use their abilities, the same would be true for people using the power. [Answer] Several answers have covered the catastrophic consequences of this power, both in the short term and as we approach near-extinction. Let's talk about how a society could stay meaningfully connected despite its new handicap, assuming it doesn't destroy itself within days. ## Children @Frostfyre covered the problems that arise from infants/toddlers/teenagers being able to kill with a thought. Assuming we can't save the ability until adulthood (and that that would help), how do we survive our offspring? ### The cop out Maybe children are actually safe. Certainly in normal circumstances, accidentally dropping a brick from a roof will kill someone as effectively as intentionally doing it, but this power comes with the explicit definition that you won't accidentally kill someone. If you don't yet understand that people can end forever, can you intend to end them forever? However, even your child remembering you from when they were 5 is a persistent danger. ### Isolation Infants can be nurtured safely until they develop coherent thoughts at all, which gives them a year or two to be raised by their parent(s). Once they develop any kind of intentional action or understanding of cause and effect, they are moved to solitary confinement. In isolation, interaction happens through modulated video and audio, and necessary physical presence is done in a uniform that masks face and body (we do this today to [maintain wildness](http://www.marinemammalcenter.org/what-we-do/rehabilitation-release/rehabilitation.html) in rescued animals). Either we must trust caretakers, or the children are also in uniform, and every interaction is randomized to avoid familiarity and recognition. Education is automated and self-taught as much as possible. Of course, this will have enormous detrimental effects on later social behavior and mental health. ### Socialization At some point, you have to learn to be a part of society; we can't just bring you out of a room after years in confinement and expect you to function. We can't even do that properly with sane, convicted adults today. So as you grow up, you get "friends" to the extent that it's safe. First, you learn to play a game with a computer - a very mechanical game, with no real room for improvisation or creativity. When you're consistent at it, you play it with other children: in isolation over a terminal, then through glass, then eventually in the same room. Both of you are in uniform, and if either of you deviates from the game in a way that might identify somebody, the game is cut short. The game gradually becomes more social until it involves multiple other people and more freedom, but at that point you've all learned consistent-enough behavioral skills that short interactions are feasible without leaving an impression of individuality. ### Graduation Society needs some way of determining a person is fit to enter it, and passing calculus is too low a bar. To be considered an adult and emerge from your childhood confinement, you must pass rigorous psychological and behavioral screening. Constant observation during adolescence provides history to a panel that makes the decision. If we don't trust our caretakers, this observation is anonymized - a pool of workers is given short clips of random, uniformed children and asked to document their behavior. Graduates are allowed into society on the basis that their education ideally has prepared them to control their impulses, but at least taught them to keep themselves indistinguishable. What happens to those deemed unfit to enter society is left as an exercise for the reader. ## Social norms On the assumption that you trust no one, or very few people, social interactions hinge on conducting oneself anonymously. The most obvious aspect of that is a uniform that masks your face, body shape, gait, voice, any anything else we're concerned about. I'm thinking [Rorschach](https://en.wikipedia.org/wiki/Rorschach_(comics)) jumpsuits and voice modulators. Maybe people express themselves through fashion, but if they do, that season's color is truly ubiquitous. The morning news tells you what the most people are wearing that day, and on Friday we all wear Hawaiian shirts. You don't have a name, or if you do, it lasts only as long as the current interaction. Conversation is terse and communicates only the necessary information, with no displayed emotion or identifying idiosynchracies. Come to think of it, when this calamity strikes, hope you're on Vulcan. People with identifying characteristics like tics, speech impediments, or unmaskable physical differences leave their home at great risk. You don't tell anyone where you live. You move frequently so your neighbors don't notice your habits, which you do your best to randomize. Either you have a dozen different soaps so you smell different every day, or everyone uses the same generic brand. ## Technology A plethora of automated assistants appear that help you manage yourself. They alert you if you use a phrase unusually often or visit the same coffeeshop too regularly. Everybody uses them, and no one talks about them, because they warn you not to mention what they warn you about. All browsers block ads and use Tor, because a database of identifying marketing information is a database of death wishes. Either Facebook shutters itself on ethical grounds, or the rush to delete profiles DDoSes the site into oblivion. Your cell phone is paid for in cash or cryptocurrency (credit cards collapsed right along with the marketing industry) and randomizes its IMEI constantly. Only data plans remain, since it's not like you're giving out your number. Soon, no one will remember why it's called a "phone". ## Law Luckily, this dystopia doesn't need imposingly anonymous, masked police. Everyone's anonymous and masked, the police just carry guns. Most crime is unchanged, since "the masked man who stole my purse" isn't enough to kill, though identity theft is a cute euphemism for assassination. Judicial proceedings are simplified because it's virtually a requirement that the defendant be arrested during or just after the crime is committed - otherwise, they have no identifying characteristics. They are kept in isolation both to protect them from the plaintiff and just to keep track of them until the trial, which consists of each person privately telling a judge their side. No one's entitled to a jury of their peers, and no one wants a dozen strangers getting to know them anyway. Fines must be assessed immediately. Prisons are 100% solitary confinement. Capital punishment amounts to publishing your face. ## Work Everyone works on a team of people chosen at random from a pool representing their skill set. Coworkers rotate through constantly, because staying amongst the same people for any amount of time is dangerous. Everyone has at least two co-bosses, who are rotated similarly, and the redundant structure goes all the way to the top. This provides enough continuity for work to move forward without anyone being able to distinguish an individual, but there is efficiency lost in the constant churn. Employee evaluation is pointless, since there is no lasting record or means to recommend you to future employers. Workplace issues like safety or harassment result in immediate termination, because there is no way of giving you three strikes. You get paid at the end of each day because there's no telling if you'll come in tomorrow. If you misrepresent your ability to do the job, they call the cops. ## Relationships It's obviously difficult to develop friendships, let alone romantic involvement, though there are plenty of meetups for like-minded people in sufficient numbers. Making a real friend is one of the most difficult, dangerous, intimate things you can do. Everyone is constantly on guard and just passing through, but there is enough interaction that you'll eventually find just a small handful of people to very, very, very slowly get to know. Since everyone's passed their ready-for-society test, there's actually not as bad a trust baseline as their could be. A sufficiently close relationship—which perhaps we could call marriage, though it doesn't have to be—is bonded by showing your faces to each other in the presence of a (safely masked) third party officiant. The officiant is employed by the state (or some other trusted entity), and gets a feed of recently deceased faces, which he checks every day for one of you. If one dies, he kills the other. The officiant makes long-term relationships safe, sexual or not, but obviously that's a supremely high bar. All other sexual encounters are like the rest of society's interactions - brief, impersonal, and anonymous. Undressing is risky if you have an identifying birthmark, but alcohol helps erase the details. Seeing someone's face is the obvious fetish, and there's a whole industry around CGI heads and human masks. ## Optimism That this society provides no room for error is stressful, but has its upside. Concern for their life if they tick someone off keeps them civil, maybe even kind. Pre-killing-power, calling someone a name might get you yelled at, but if you're not willing to risk death on the other person not figuring you out, you'll hold your tongue. And for the most part, nobody wakes up wanting to kill people. Just as you're trying to avoid doing anything that'll get you noticed, you actively ignore everyone else so you don't accidentally gain the ability to end them. Everyone generally minds their own business and avoids conflict. ## Pessimism This society lives in constant fear of retribution for the slightest social misstep. They wear masks outside, try to look and act like everyone else, and don't open up to anyone in case it comes back to haunt them. Everybody exists in their own, isolated universe, passing by myriad other equally inscrutable, equally lonely people, always wondering if they can risk getting close or trusting someone. But really, does that sound so different? [Answer] You need to add another rule: the power manifests itself at adulthood. Giving such power to children, who have difficulties with cause and effect anyways, would be pretty much catastrophic. Imagine a two-year-old whose tantrums are lethal. Actually, it's been done. ["It's A Good Life" by Jerome Bixby](https://en.wikipedia.org/wiki/It's_a_Good_Life) is really creepy. > > Anthony Fremont is a three-year-old boy with near-godlike powers: he > can transform other people or objects into anything he wishes, think > new things into being, teleport himself and others where he wishes, > read the minds of people and animals and even revive the dead. > > > Anthony's powers were present at birth, as he was able to kill the > obstetrician > > > Anthony decides Dan is a "bad man" and turns him into some sort of > horrific entity (described only as "something like nothing anyone > would have believed possible") before "thinking" him into a deep grave > in the cornfield. > > > Even with this addition, it's important to keep in mind that there are monsters among us. There are those who take deep offense at any imagined slight, and there are sociopaths who do not recognize other people as being "real". There are paranoid schizophrenics who imagine that virtually everybody is part of an organization which is deeply inimical. It won't take many of these to cause major loss of life and social breakdown. Then things get really bad. [Answer] Society will survive and eventually stabilize by making this impossible: > > But you do need to be able to distinguish this person from another person. > > > And they will do this by loophole - make sure that all new births are identical twins (or triplets, or more), through a combination of in-vitro fertilization and fertility drugs. They could also, potentially, use plastic surgery and such to make people into "fake" twins. Each pair will be given the exact same name and will maintain identical physical appearance and activities to keep themselves indistinguishable. They'll effectively be the same person, from a legal and society viewpoint. I'm aware this isn't how twins currently work, but since it's a matter of life and death I think they'll adjust. This will limit the power's usefulness to close friends and family who are able to distinguish between the two somehow, by knowing them closely. Since purely physical criteria isn't enough: > > you met a masked man, you couldn't just kill the masked man > > > You can't just say "kill John Doe on the right" - you need to know them, and if they're otherwise identical on a surface level the power will fail to function. [Answer] There would be many more deaths, but it wouldn't be catastrophic. People tend to kill each other all the time, but when you think of how easy committing many crimes are, and how many people there are, it's surprising how few people are harmed. I imagine that your world is similar, that although everyone could, most people have decent morals. Of course there would still be a ton more murders, especially in already high-crime areas where people might already be on the verge of an attack. The police could try to manage this, I know you said that it can't be tracked, but I'm sure that they could at least find possible suspects (people they disagreed with, etc.), and they would definitely have to defend against the small percent of the population that is certifiably psychopathic. This could be done by just following the path of destruction and then thinking about the only guy left standing. Celebrities, politicians, and other public figures would all be toast, and I also have to agree with @WhatRoughBeast that the power should be taken away from kids. But other than a spike in homicide, I don't think it would have a huge effect, and could definitely sustain a society (a really timid and polite society). [Answer] The human race would probably be much smaller. If we are to assume society does function (instead of just collapsing), then it would make sense that the race would find a way to reduce the threats posed. I think the most interesting rule here would be the one about the masked man scenario. If differentiability is a necessary condition for this method of killing, then it would make sense that human beings would develop cultural conventions to the effect of remaining indistinct to strangers until individuals felt they had acquired sufficient information to justify the risk. Technically speaking, even reproduction could be made anonymous, through either the use of artificial fertilization, "glory holes", blindfolds, and I'm sure ten thousand other things I can't think of at the moment. If we assume, however, that individuals will crave human interaction for its own sake, then these conventions of nondifferentiability will have to occur. It seems the biggest question involves human interaction. The standard of living possible for a person in isolation is quite low compared to what has been standard for at least centuries. Specialization of labor means that we must interact with people we do not know well, but who can do a job we do not. That is, I may not know the grocer particularly well, but his shop serves a purpose in my life by making available the eggs and milk. I am not close friends with the baker, but I still need to interact with him if I want any bread with my dinner. The question is how people would reconcile the need to do business with people we don't know too well with the competing need for anonymity. It seems reasonable that conventions would be developed to introduce greater anonymity to these processes. For example, we might see the phasing out of cashiers in favor of self-checkout. We might see the growth of automated business, i.e. electronically purchasing the groceries and receiving them by a drop-off, or even an another automated system of delivery. But I think that electronic payment systems might not have a huge change, because simply having a person's address doesn't seem like it'd be sufficient information in itself to qualify as the ability to differentiate a person enough to kill them. Another question of interest for me is the question of policing, i.e. the quis custodiet ipsos custodes question. If the police are understood to be "mandatory", i.e. if I as a resident of Townsville am by default subject to the Townsville Police, then it would seem very hard to enforce a system of accountability, and would give the police force little incentive to function as defenders of their charges; that is to say, there is little reason for the Townsville Police to exercise restraint, and moreover the Townsville Police could very easily flaunt any sort of check, as murder would be exceedingly difficult to trace back to the murderer. Though I don't know that it would be an obvious or inevitable conclusion, a system of privatized police doesn't seem absurd in this lens, as a police force whose charges tend to die in an unusually high number would be more likely to be dismissed. This unusually high number might be due to a proliferation of crime or police brutality, but in either case the problem is most likely with the police force. This would, of course, be an imperfect system, but the idea of the Townsville Police would sound quite suspect here if one was effectively stuck with the Townsville Police, instead of having options. I disagree, however, with Kristjan's assertion that the jury system would be overhauled. It seems that the trial by jury could be maintained, so long as sufficient nondifferentiability were introduced. There are already conventions in place which are used when a witness's identity is meant to be kept secret. It might be a sort of confessional-type thing, where individuals can be heard but not seen. It seems, however, reasonable that these conventions should develop organically as a spontaneous order. The conventions proposed already would occur naturally by individual volition once it became apparent that these problems needed solving. Moreover, history shows that it can often be hard to predict how exactly individuals will adapt to new conditions, but the one thing that can be counted on is that they will, even if it's not a top-down plan, or perhaps even being consciously reasoned as an explicit solution (e.g. if there's an egg shortage, I might not necessarily know there's an egg shortage, but if it persists, then I will be likely to notice the increase in the price of eggs, and adjust my behavior accordingly). [Answer] If children have the power then that's a whole new world of pain, but assuming it kicks in around adulthood: Knowing who someone is is the ultimate power so the control of that state is the primary means of exerting power. A small number of individuals will position themselves at the top of the pyramid. They will only ever appear in public completely covered in identical outfits and with voice modulators that prevent them being recognised. They will likely know who each other are, but the maintenance of their power structure relies on them having enough in their cabal to remain indistinguishable among those beneath them and this, and common interests, will maintain safety among them. They will create beneath them a hierarchical structure of identi-groups all of whom are known to those above but wear identical clothes so that no-one below them can be identified. They'll be held collectively responsible for any unidentifiable breaches on their part and the whole lot mind-executed if they cross the line. Fear of those above, and the rewards of rank will keep them largely obedient. The unwashed masses at the bottom will be obliged to keep their faces uncovered at all times. Identical twins will be tattooed or branded shortly after birth to ensure they're identifiable. Deaths among the faced will simply be a fact of life. Their masters will kill those they suspect of killing others but, basically, they're interchangeable labour so it doesn't matter that much and most people aren't psychotic enough to kill people on a whim. Rioters, or similar, who try and hide their identity will be killed using conventional weapons reserved for those at the top. Those near the top will enjoy many privileges under this system but also the constant fear of execution; for those at the bottom it will be an unrelenting dystopia. Faced with the fear of arbitrary execution, society will become exceedingly polite so as to avoid unwittingly offending others. [Answer] # We will go back to being cavemen!!! With only family to trust(maybe) people will seize to even talk to other people. That will demolish everything...from business meetings to inviting people over to your place. So everybody will start living in fear inside their houses just like cavemen. As the time will pass everybody either will die or will become fully self dependent(from growing a steady supply of food to keeping your mind calm) i.e V.hard without someone to trust. ]
[Question] [ You may assume the rainfall will match that of a Tropical Rainforest at [their wettest](https://sciencing.com/average-rainfall-rainforest-5068456.html) (304 in. annually). --- How would this change the landscape over time? (0-100 years) [Answer] Something like this has actually happened once already 100 years wouldn't be enough to turn the Sahara into a savanah, but it would be a good start. From [this source](https://www.livescience.com/4180-sahara-desert-lush-populated.html) we read the following (emphasis mine): > > But around 10,500 years ago, a sudden burst of monsoon rains over the vast [Sahara] desert transformed the region into habitable land. > > > This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites. > > > "The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany. > > > So, 200-500 years of monsoon rains would get you a savanah. 100 years might only get you grass and scrub brush. Please note that for a long time the desert would simply drink the water. Sand doesn't hold water well, and the underlying aquifer would need to recharge. After that the water table would be high enough to sustain regular rivers, ponds, and lakes. That's when the real growth would begin. But even then, sand sinks. It would take a long time for grass to take root, holding down the sand and creating a bed of organic mass that eventually turns the top layer of sand into soil. This process is fast by geological standards, and painstakingly slow by human standards. Therefore, after 100 years the Sahara would be spotted with ponds and lakes connected by streams and rivers with grass and low bushes growing along the banks. Maybe even some trees. But between all that would be desert. Not as barren as the original, but desert, nonetheless. Flooding would be a regular problem as it would wash out banks and move the location of rivers (much as it did with the Rio Grande before dams controlled the run-off). This is actually an important part of the process as it distributes organics around, speeding the process. Without periodic flooding, that 500 year maximum might be an optimistic minimum. Also, note that 300 inches of rain a year will cause massive initial erosion. The existing landscape would be dificult to recognize after the first 20 years or so. But, once plants started kicking in, the amount of rain wouldn't change things that much, other than to make the area difficult to inhabit. If what you're looking to do is transform the Sahara into a rain forest, you'll need a great deal more time than a century. It might take a millenium. Rain is necessary, but not magic, and more rain won't speed plant growth. Once you reach a maximum saturation point, all you get is run-off. [Answer] # That is a lot of rain Runoff will carve rivers as excess water goes to the ocean. Take a look at the basins to see what will happen. [![enter image description here](https://i.stack.imgur.com/iCVDR.jpg)](https://i.stack.imgur.com/iCVDR.jpg) It appears there will be five basic river systems. There will be an Algerian system, gatheringr rainfall from the north and west of the Haggar ranges and emptying into the sea in southern Tunisia. There will be a Libyan system, emptying the east of the Hagar ranges and everything north of the Tibesti mountains into the Gulf of Sirte. There will be increased Nile runoff, with some collection in Egypt, and more in the Upper Nile region. Lake Chad will fill to the brim, probably forming the largest lake in the world before overflowing and emptying into the Benue river and then the Niger and Atlantic. Finally, the rest of the runoff will gather into the upper Niger. Given the amount of rains involved, the Niger and Nile will probably both rival the Amazon in size. # Massive sand removal and erosion Because there are currently no plants, there will be a lot of sand lost in the first decade, given that much rain. Infact, I would venture to say that you will lose all the free floating sand in the Sahara. The rivers that I mentioned will form enormous deltas as all that sand is thrown into the sea. The Nile's swampy delta will reach Cyprus; the Niger's to Gabon. The Mediterranean in particular, with three massive rivers running into it, will be very much changed. # Rainforest plants will move north There are plenty of rainforest fauna in both West Africa and Cameroon, not too far from this magical rainfall. From here, plants and animals will expand into the new Sahara. This will take some decades probably. At first, nothing will be able to live. The plants of the Sahel region to the south and the Mediterranean coast to the north will not be able to survive the wet enviornment. Mediterranean plants such as dates can't pollinate if summer rains ruin their flowers; olives can't survive waterlogged soil. The plants of the dry southern savanna (Sahel) will also fair poorly. Until rainforest plants get to the region by whatever means, nothing will grow. This process will take decades. # Eventally you will have a rainforest The slopes of Mount Cameroon recieved the kind of rainfall that you are envisioning, so there are clearly plants that will be able to survive this environment. Eventually, the landscape will look like those tropical forests. But given the time it takes to grow trees this tall, it will take several centuries before the plants propagate in the required densities and grow to mature height. [![enter image description here](https://i.stack.imgur.com/Aqlqk.jpg)](https://i.stack.imgur.com/Aqlqk.jpg) [Answer] You would immediately get humans moving in and cultivating the land. Sand isn't great for most crops, but there are plenty that can be made to grow with a bit of help. There are plenty of examples of desert gardens in the World even with low tech. With this input you would soon see more and more cultivation and probably within 100 years the desert would be a sought after and probably fought over land. [Answer] The biggest problem would be the soil composition. Sahara's soils are underdeveloped due to reduced organic matter and water so they aren't very fertile and wouldn't be able to sustain a forest, that's why even with a lot of water you would need to wait for the soil to develop (keeping in mind that rainforest's soils took many years to form) while ecological succession takes place. Some sources say that process takes from 500 to 3000 years, but it should take more time since the Sahara has a lot of sand. But the amount of rain you are proposing could be too much. A lot of water can be damaging by stripping the soil of it's nutrients, reducing its oxygen levels and killing small plants that might start to grow as well as microorganisms, insects, etc and thus getting in the way of turning the desert into a forest. [Answer] My brother lives in New Mexico in a part where they average 7 inches of rain a year. I asked him what would happen if it got a typical mid-western pattern of 25-30 inches a year. "Floods, landslides most of the vegetation would die." The land isn't covered with vegetation, so the erosion will be immense. In large parts of the Sahara the aquifer isn't far below the surface. With 300 inches a year, you have enough water to saturate 75 FEET of sand. Most of it will run off. Hopefully you end up with a large number of fresh water lakes, which will allow you to practice experimental lake ecology on a large scale. Overall I'd do nothing until the sand stopped moving, then on the gravely bits I'd try plants that fix their own nitrogen, and that tolerate soggy roots. [Answer] You're talking crazy amounts of rain for a hundred years. The Sahara's soil is not really designed to host life, and even with tons of water every year, you still will not be able to get the forest I can see in your head. It took a long time for the a rainforest to turn into one, so if you're thinking about adding an entire layer of sand to the mix, ummm.... With even 304 inches of rain, it would still take a thousand years to make the Sahara even habitable, and that's not even a rainforest! Decrease that thousand years to one hundred, and all you're going to get from this much rain would be just mere shrubs and grass. If the rains abruptly stopped, and the weather returned to what it is now over that desert, those traces of vegetation will be gone by the end of the year! And, as mentioned by cls, that much rain may be too much, as it doesn't take a degree in biology to know that the amount of water you are proposing will probably wash the nutrients in the soil away, therefor you'll be nullifying many chances to grow a forest. You're also going to be killing much of the plants and animals already adapted to life in these conditions, and it isn't likely those life-forms will be coming back until you stop the rain. ]
[Question] [ When we talk about orbits we often imagine a ship or station orbiting a planet outside its atmosphere. Is it possible a ship could go into orbit inside its atmosphere (perhaps to hide from other craft) or would it be torn apart by the gravity and atmosphere of the planet? [Answer] It would lose speed due to drag and fall in. If you're thrusting to maintain speed, just fly like a plane and don't try to orbit. The hypersonic speed of orbital velocity would be conspicuous anyway, not a good way to hide. Do you have any idea how fast orbital velocity is? Low Earth orbit is about 17500 miles per hour. Imagine doing that while still having air around you. The heat of ["reentry"](https://en.wikipedia.org/wiki/Atmospheric_entry) is caused by ram pressure: imagine that all the time! Now realize that around Jupiter the needed speed would be one or two orders of magnitude faster several times greater: about 94200 miles per hour as estimated by Michael Kjörling. [Answer] Like JDługosz wrote, what will cause problems in the scenario you describe isn't so much your orbit as the fact that you are within the gas giant's atmosphere. I'm going to use Jupiter here to have some specific gas giant to use for examples. Feel free to look up the relevant data for any other gas giant, or come up with your own. For the case we are interested in, a small mass orbiting a much larger mass where the radius of the orbit is equal to the larger body's radius (just dipping your toes into the Jovian atmosphere), [orbital speed can be approximated](https://en.wikipedia.org/wiki/Orbital_speed#Mean_orbital_speed) as $$ v\_o \approx \frac{v\_e}{\sqrt{2}} $$ [The escape velocity of Jupiter](http://nssdc.gsfc.nasa.gov/planetary/factsheet/jupiterfact.html) is approximately 59.5 km/s, so to dip our toes into the atmosphere we get an orbital velocity of approximately $$ v\_o \approx \frac{59~500~\text{m/s}}{\sqrt{2}} \approx 42~100~\text{m/s} $$ To give an idea of how freakishly fast this is, it's equivalent to approximately 152,000 km/h or 94,200 miles per hour. It gets you between the Earth and the [Moon](https://en.wikipedia.org/wiki/Moon#Orbit) in 2.5 hours. In mid-1976, [an airplane managed to get to 3,530 km/h](https://en.wikipedia.org/wiki/Flight_airspeed_record#Official_records_versus_unofficial), which is about 1/43 of the orbital speed at the edge of Jupiter's atmosphere. The best we have managed on anything resembling a repeat basis is [around 2,500 km/h](https://en.wikipedia.org/wiki/Flight_airspeed_record#Timeline), or 1/60 of what you would need. For comparison, [Jupiter's wind speeds peak in excess of 150 m/s](https://www.nasa.gov/centers/goddard/multimedia/largest/atmosphere.html). While quite a stiff gale, that's nowhere near orbital velocity; by the above estimate, about 1/280 (and that's assuming that top wind speeds occur in the uppermost layers of the atmosphere, which might not be the case). With such a large difference between orbital speeds and wind speeds, we can largely ignore wind speeds for the purposes of this question; even in a perfect situation, wind speed will contribute less than 0.36% of the required velocity. (Interestingly enough, according to the same source, Jupiter wind speeds have a peak very near the equator, which works well for us.) Given that [Jupiter has an equatorial diameter of 142,984 km](https://en.wikipedia.org/wiki/Jupiter#Physical_characteristics) and that the circumference of a circle is $\pi d$, 42.1 km/s gives an orbital period (if you can call it orbital) of $\frac{142984 \pi}{42.1} \approx 10~700~\text{seconds}$ or just under three hours. For comparison, Wikipedia gives Jupiter's sidereal rotation period ("day") of 9.925 hours (a shade over 9 hours 55 minutes). For comparison, to get into a reasonably stable low Earth orbit you need a velocity of approximately 7.8 km/s (corresponding to an orbital period of [about 90 minutes](https://en.wikipedia.org/wiki/Low_Earth_orbit#Examples)). To go to the Moon (which is pretty close to escape velocity), you need about 10.5 km/s relative to the Earth. Actual [Earth](https://en.wikipedia.org/wiki/Earth) escape velocity is 11,186 m/s. Compare [Apollo by the numbers: Translunar Injection](http://history.nasa.gov/SP-4029/Apollo_18-24_Translunar_Injection.htm) and look at particularly the Earth Fixed velocity figures for the various lunar missions. Let's say you can somehow handwave the issue of absolute speed away. (After all, you got there somehow, and that already takes quite a bit of speed.) Let's also say that your craft is a very, very long, perfect cylinder with a forward cross section of 1 square meter, built to handle [constant hurricane-level wind speeds](https://en.wikipedia.org/wiki/Jupiter#Cloud_layers). Every second, you are moving through 42,100 meters of atmosphere. That means that every second, your craft will need to push aside 42,100 cubic meters of atmospheric gases while maintaining its speed (at least if you plan on staying at that altitude). Wikipedia gives [the composition of Jupiter's atmosphere](https://en.wikipedia.org/wiki/Jupiter) as approximately $89.8 \pm 2.0 \% ~\text{H}\_2$ and $10.2 \pm 2.0 \% ~\text{He}$. Despite the fact that these two gases are among the lightest known, and that the density is going to still be low at the altitude we are talking about, pushing aside over 40,000 cubic meters of gas per second is going to cause some massive [drag](https://en.wikipedia.org/wiki/Drag_%28physics%29). And that, my friend, is what will cause your craft to [heat up](https://physics.stackexchange.com/a/17951/14091), lose speed very quickly and eventually descend into the atmosphere, [ruining your day](https://space.stackexchange.com/a/5041/415). [Answer] While JDługosz and Michael are scientifically correct with their answers, I think we are overlooking something here. If your fictional spaceship can sustain flight indefinetely, it can go inside the atmosphere and fly around the planet on its own. This is not the same as orbiting, as it requires powered maneuvers, but more like flying a plane on Earth. The conditions of the atmosphere of gas giants we know of is a lot different from Earth's own, though, so this is going to take some handwaving or more serious research. But with sufficiently advanced technology, this would be doable on Jupiter. [XKCD has something to say about that:](https://what-if.xkcd.com/30/) > > Our Cessna can’t fly on Jupiter; the gravity is just too strong. The power needed to maintain level flight is three times greater than that on Earth. > > > If your spaceship is approximately the size and weight of a Cessna 172 Skyhawk, and can provide three times as much thrust as that airplane, then it can (probably) fly safely on Jupiter (just be careful you don't enter any storms). For larger, heavier ships, it's just a matter of scaling the power up as needed. Now you might say this brings another problem into question, you'll need continuous application of power. And if you won't take renewable power sources that you can use while in there, this strategy is a poor one. Indeed, that's why you wanted to be in orbit in first place - you don't want to spend fuel to keep your craft flying inside that atmosphere. Alright. Just pop one or more balloons open. Granted, you might need a lot of really large balloons, but again... You would be able to hide inside Jupiter's a gas giant atmosphere, while largely avoiding falling into the planet core. Just be careful to avoid any storms. Edit: as JDługosz and Ross pointed out, a balloon filled with Hydrogen or Helium in the atmosphere of Jupiter would not be buoyant, unless you could heat these gases to be hotter than the surrounding atmosphere, and even then it might not be buoyant enough. This balloon idea would very probably not work on the gas giants of our solar system... It would work on a fictional gas giant that has an atmosphere composed of heavier elements, though. I got this inspiration from a videogame (Windforge) for which the world is a gas giant with an nitrogen/carbon dioxide/oxygen atmosphere, and the player and NPC's navigate through it in airplanes and zeppelins. So... Some parts of handwaving and suspension of disbelief may be necessary for this idea to be considerable. [Answer] # Hide in orbit Hiding spacecraft is really easy because space is so big. Jupiter already has a lot of rubble orbiting it, if you orbit with the rubble, and turn off your engines and radio, no one will notice another piece of rubble, especially if your ship is dark grey and dull. Turn the heating low and insulate well to hide better in infra red, but as the rocks are heated tidally and by collisions, even a warm spacecraft will be non obvious. [Answer] Only if you were to somehow be able to make the vessel immune to the friction of atmosphere or allow it to phase through matter. In the former, you'd probably have to continue to add some kind of propulsion. [Answer] Simply put, the difference between orbiting and flying is the friction caused by the atmosphere. When you "orbit" you fall fast enough that you miss the ground, and slow enough that you don't go zooming off in a direction. Flying uses the pressure of the atmosphere and the speed your going to generate lift. If you were to go fast enough to miss the ground in the atmosphere, you would have so much friction with that atmosphere that you would slow down and hit the ground. The term is usually referred to as Air-Breaking. You can go fast enough to "skim" the atmosphere a little, then end up with a lower aspoapsis but if you stay in the atmosphere too long you just keep slowing down. If you apply continuous thrust, then your flying. And your objective changes from going fast enough to miss the ground, to fast enough to generate lift. So you can't orbit inside an atmosphere. You could, however, in theory, go from low orbit to high altitude flight, and then back to a low orbit after a while. It would be pretty hard on a space plane though, and waste a TON of fuel. ]
[Question] [ My question is not human-specific. I found [this](https://biology.stackexchange.com/questions/2415/is-it-possible-for-any-animals-today-to-have-more-than-one-brain) question that mentions that a brain have more neuronal complexity; I deduce it is more efficient (in terms of neural communication and energy use) to put all the higher complex mental functions in one large organ (tell me if I'm wrong, I'm not a biologist). But in an alien planet, where living carbon-based creatures have plenty of resources and food, could they evolve to have a series of interconnected small brains with the same functions of a large one? These brains could be located across one limb or across the back. [Answer] # Yes. For large animals, octopuses are a possible source of inspiration. [They have neurons in their arms](https://www.scientificamerican.com/article/the-mind-of-an-octopus/), which lets them have a very large brain-to-body ratio. This does let their arms move without as much direct control from the brain. You could also argue that this sort of structure can be found in leeches. [They don't really have 32 brains, one inside each body segment](https://www.quora.com/Is-it-true-that-a-leech-has-32-brains), but they do have one [ganglion](https://en.wikipedia.org/wiki/Ganglion) per body segment, which in a sense exerts local control over that segment. Each ganglion cannot operate independently from the others - that is, it's not like there are 32 individual nervous systems working in unison. Keep in mind that the segmented structure of the leech is what makes this sort of thing evolutionarily possible. You're probably not going to see this arise in animals like humans, for instance, because there's simply no need. A centralized organ is much simpler than miscellaneous localized ones. [Answer] Sort of. We kinda have that already with a brain split into three sections (left hemisphere, right hemisphere, cerebellum). But there is a lot of connection between those sections which will take up a lot of space, this gets exponentially worse if they are are spread apart. In our brain the connections are roughly a third as big as the parts it separates, so the more your spread it out the bigger the brain ends up being and the more resources it takes to maintain it. As it is our brain eats a third of all our calories, so making it bigger with no benefit is not likely to evolve. Your biggest problem is the further apart they are the slower information travels between them, so your creatures will end up thinking slower and being less coordinated, worse if far from sense organs it also reacts slower which is pretty detrimental. The closest you can come is to have a cerebellum like structure for each limb independently instead of one large one. (octopi are believed to function like this) but the thinking portion is still centralized. [Answer] There is a being in a somewhat alien environment whose brain(s) have evolved precisely in that manner: the octopus. <https://www.scientificamerican.com/article/the-mind-of-an-octopus/> They have a quite sizable set of neural tissue, with the largest brain to body mass ratio of all invertebrates. The organization of that neural tissue is also remarkable: about two thirds of the neural tissue are located outside the brain, in the tentacles; each tentacle has its own bundle of neurons, capable of doing some information processing and even sending commands to the muscles. The central brain can command the tentacles if necessary, but they can also react on their own. So, if it has already happened in our own planet, it's most certainly possible for it to happen to beings in a different planet. I'm not sure if this layout could eventually reach human levels of intelligence, but I don't see any reason why it couldn't, given the appropriate environment for the species to evolve a brain that large (if any biologist or neuroscientist wants to correct me on this, I'm all ears). [Answer] In Vernor Vinge's "A Fire Upon the Deep", there is a planet inhabited by dogs which operate in packs of about 5 apiece as an aggregate personality and intelligence, bound together by sonar communication. (They have ascended as far as medieval technology at the point of the story.) As members ("parts") are separated from the group ("person"), the group becomes less intelligent until eventually each single part has devolved to mere animal intelligence and behavior. When two or more "people" (i.e. packs) come into very close contact with each other they can become confused or otherwise lose their higher-order thinking ability due to the cross-talk of all their sonar. (This makes reproduction - and battle - a bit tricky). Streets are very wide so they can pass each other, and I assume rooms are very large as well if more than one is to perform any task in them at the same time. (They have five "hands" but each is less dexterous than one of ours, of course.) Swapping parts in or out of a "person" is avoided in all but the most extreme cases - such as after deadly skirmishes between enemy clans... [Answer] From bees hives, I know they can make decisions as a whole, and it is not exactly known how they do that. For example, if a swarm of bees want to leave the hive with the queen, about half flies away and half stays. How do they decide this? Bees can communicate in several ways; with odor, touches, and movements. Even the sound of the hive tells the beekeeper something about its mood. Many little brains communicate with each other and make a decision concerning all of them. I imagine something similar (creatures with a single brain) but able to communicate in a much more advanced way than humans. Imagine something like humans (or completly different), but able to communicate like bees, connecting their abilities of intelligence. Maybe they would be further able to connect physically, allowing information transfer between multiple brains in multiple ways. Maybe they could form a single creature consisting of many connected individuals, acting like being one, but still able to cleave. [Answer] Hmm ... a lot depends on what these extra brains are, well, for. There are some great examples in nature and other answers of distributed brains for locomotion or "taking care of" body parts. Think Stegosaurus! It makes sense ... each little brain controls a segment or a tentacle or somesuch, and the "main brain" just has to send out high-level commands. Where it gets a little tougher is distributing thinking functions. There seems to be little benefit to scattering this around the body... what are we buying in exchange for the extra time-lag? [Answer] This has been done in fiction before. This is Ki-Adi-Mundi, from the Star Wars universe: [![Ki-Adi-Mundi](https://i.stack.imgur.com/qTzPb.jpg)](https://i.stack.imgur.com/qTzPb.jpg) He belongs to a race known as the Cereans. [From the Wookiepedia](http://starwars.wikia.com/wiki/Cerean), emphasis mine: > > The Cereans were a species of sentient mammals hailing from the planet Cerea. They were distinguished by their enlarged conical cranium that contained a binary brain. > > > See also [the Ood race](http://tardis.wikia.com/wiki/Ood), from the Doctor Who TV series. These guys have a brain in the head and a secondary brain connected to the face through something like an umbilical cord. [![A few oods holding their secondary brains in special cases](https://i.stack.imgur.com/Xfzwd.jpg)](https://i.stack.imgur.com/Xfzwd.jpg) --- In the past I have answered [a question about hormonal sentience](https://worldbuilding.stackexchange.com/a/43964/21222). This was about a plant or fungus creature or species that would have no identifiable brain, but rather working its consciousness through the usage of hormones to mediate chemical signals. In such a creature, you could think of each gland (or other kind of hormone-producing organ) as a separate brain or brain part, and they can be spread throughout the body. As with any other answer in this site, you can use my answer there as a basis for such a creature, tayloring it to your story writing needs. The only limit to how such a creature might be formed and how many brains it can have is your imagination. [Answer] We already have something similar. The brain is build up of loads of modules that mostly cooperate, but sometimes work against each other. Read "Why everyone (else) is a hypocrite" by Robert Kurzban. It elaborates why we have this brain structure and how it works in detail. He's an evolutionary psychologist and explains this very well and in detail. I guess you could also put physical distance between module clusters and everything would still work. ]
[Question] [ I've been toying with how to word this question but I can't think of how to word it well. Under current British law would it be possible to 'privatize' the government? In my scenario I'm wanting a private company to take over the running of the country effectively turning it in to a disguised dictatorship, but I want it done by the book. Is this possible with the current method of passing laws of England? [Answer] Technically, the United Kingdom is a Theocratic Dictatorship, ruled by the whim of HM the Queen, which is normally expressed through parliament. That means that any change of law, up to and including the abolition of the monarchy and parliament itself, is possible. To privatise the government, [you'd need to introduce a bill](http://www.parliament.uk/about/how/laws/passage-bill/), most likely in the House of Commons. It would go through three Readings, in which the bill is debated back and forth by all members; there's a vote to move to each stage. You'd need a simple majority of the MPs on your side for each vote to pass it along. The bill would then go to the House of Lords, where it goes through the same process. The Lords can propose amendments to the bill; if they do, the bill then has to go back through the Commons. So you'll need a majority of both the Commons and the Lords to pass your bill. If it passes through all those steps, it would go on to HM for Royal Assent; when the Queen signs the bill (normally a formality), it becomes law. Which means nothing. Unlike other nations with written constitutions, British government works on precedent, tradition, and custom - but those traditions and customs can be pretty damn ironclad. While abolishing Parliament and privatising government may be technically legal, there is no way in hell that the electorate would go along with it. There would be huge protests, widespread civil disobedience, and a general refusal to accept the new government. If HM went along with the process (she likely wouldn't), you'd probably see protesters rallying around other members of the Royal Family - William and Harry have the popularity to carry it off - resulting in a quick declaration of a regency. If HM did NOT go along with the process, then it dies right there anyway. The most likely outcome would be the corporate government being quickly removed by the military, someone in the line of succession - Charles or William, most likely - being made Regent, and elections being held. Members and Lords who voted for the bill could, possibly, be tried for treason on the grounds of "attempting to undermine the lawfully established line of succession". [Answer] You've chosen an easy country for that. Britain has no formal Constitution. That means that every law can be changed by the parliament. So basically, yes. The only problem you'd face is making the people accept the new regime, but by the book you can achieve it. [Answer] Here is an evil plan of mine for the case I ever become filthy rich. The gist: don't privatize the government, privatize the people. Basically, you need the state in a desperate situation. Unable to pay for social security costs or to ensure the safety of citizens. Then you step up as a generous entrepreneur, and offer to "buy" a bunch of citizens (your employees and their families, or a few small cities). You don't really buy them, they don't become your slaves or anything - rather you promise to take care of them, and in exchange get their taxes and some sort of state-like souvereignity. You pay their medical bills / replace the NHS for them, you provide police and fire brigade services, send their kids to your schools. Short-term, this would be a tremendous financial relief for the state - you'd probably be able to "buy" citizens for close to zero cash. Long term you would want to make a profit, or grow so quickly that it doesn't matter. Why would you do this? The reason is that you, as a private company, don't have to operate within the same bounds as the state. The NHS has a list of services they are legally mandated to provide, but you are a private company, and your services are up to negotiation. You can cut corners in ways the government can't easily. Some stubborn traditions that are inefficient? Political parties cannot agree on a course of action? You can do almost whatever you want on your private land, hopefully more efficiently than the government could. What would your endgame be? If you play your hands well, you control almost every aspect of the lives of "your" citizens. Maybe they will even be better off than other citizens (if only because you picked the towns to buy wisely), and will be grateful. And if not, you own their schools and newspapers, so you can manipulate them. You will slowly starve the government, until it cedes more and more power to you. Finally, the old government will be a cerimonial shell, like the monarchy is today. The real power will lie in your corporation. Why would the British state agree to sell you citizens? * There is plenty of precident for privatization in the UK, even when it was less then beneficial for the people. Often, the state will prioritize short term economic gain vs. long term utility or sustainability. * There is precident for giving corporations quasi-national-state powers. Think of the British East India Company. There is also a history of company towns. * There is plenty of organisational wierdness in the UK, for example the [City of London](https://de.wikipedia.org/wiki/City_of_London) - not to be confused with the city called London - which is a private state in the city, in which not people, but corporations have voting rights. That gives me reason to believe that this would fly, too. * There is a trend to "private public space". You think you are in a public space, but it actually belongs to somebody and not the commons / the government. You have the same rights there as in someone else's back yard. In the end, you should be able to reign like an absolute monarch. The only thing you have to fear is that people do what they did back then - protest and fight to gain rights and representation in your corporate "government". [Answer] # Re-write the book There is no constitution or jurisdiction, in any country on Earth, that is unchangeable or not amendable. If you want to do it by the book, and the book allows you to, then the answer is: yes, you can do it "by the book". If you want to do it by the book, but the book does not allow you to, then you re-write the book, and then the answer is: yes, you can do it "by the book". # ... however ... You asked for a reality-check, so here it comes: people will notice. No book today is written in such a manner that — if you try to abolish democracy by the book — you can avoid getting noticed. When noticed, people will move to block your machinations. And if you try to re-write the book, then that will be noticed, for the same reason: the book is written such that it will be noticed. And — again — people will move to block you. This is because that which is written in book is only an implementation; a way to put words on something. That something is the intentions and the spirit that necessitated writing the book. And even if you, in very a lawyer-esque manner, manage to get around the letter of the book, you can never get around the spirit of that which caused the book to be written in the first place. And that spirit does not reside in the book. [Answer] Define "the government"... All utilities have been privatised for a considerable time. Prisons are run by private companies. Likewise construction, so-called "public" transport and refuse disposal. Schools have had substantial elements of privatisation. Various elements of the NHS have private competition, and some (e.g. dentists, opticians, even GPs) are entirely privatised already. How successful these have been is very questionable. Let's just say that for many of these privatised services, it costs the government more (in real terms) than those services cost when they were publicly-owned, and the quality of service is not necessarily better. Still, belief in the unequivocal benefits of privatisation is a near-religious conviction without evidence, not an evidence-based policy, and it's not possible to argue with a belief that doesn't have evidence. This means that any attempt to discusss this will simply be dismissed out of hand by its advocates. The last 30 years have also proven that the general public are perfectly willing to accept privatisation as a way of delivering public services if the privatisation advocates tell them that it will deliver those services better and cheaper. It's also proven that the general public will then tolerate the situation later when it turns out that privatisation delivers worse, more expensive public services. The failure can be easily blamed on the individual companies delivering those services, not on the systemic failure of the policy. So, how to deliver your dystopian vision? The first simple steps are to privatise policing and the judiciary. Policing is easy - we already have private police forces running prisons, transporting prisoners and providing security for various public places, after all. For the judiciary, it could be as simple as professionalising the role of judge/magistrate. Once you've got that, you're mostly set. You do have the question of where the House of Commons, the House of Lords and the Queen would feature in accepting this, though. The Commons could fairly well be rigged, but the Lords would be much harder. Even though the Lords don't have the power they used to, they can still call the Commons on doing unethical stuff (after all, that's their reason for existing). It's not the same as a veto, but it can expose the situation to the public. And the Queen would also be involved, since in theory she runs the country. As a constitutional monarchy, for her to get involved would be pretty much a nuclear option which might take the monarchy down if she didn't have the support of the public, but if the result would be bad enough for the country then it's perfectly imaginable that she would effectively lead a coup. So you need a monarch prepared to let this happen on their watch too. It seems unlikely that Liz 2, Chas 3 or Bill 4 would allow it to happen, but we've had enough bad, cowardly or ineffectual monarchs that you can't discount it completely. [Answer] It already is privatized. Parliament, the Courts, every aspect of the state serves at Her Majesty's pleasure, so, in theory, you could have a [Johnny English](http://www.imdb.com/title/tt0274166/) scenario. Of course, given the English history of violently overthrowing unpopular rulers, the coup might not last very long. [Answer] As others have noted, Britain doesn't have a formal Constitution, so the government can be changed through acts of Parliament. For most countries, it would require amending the Constitution, but again, most if not all constitutions have some legal procedure for amending them. You face the far more difficult practical problem of how you would get such changes passed. To make a story plausible, you can't just say that one day someone came along and proposed totally re-organizing the government and Parliament passed this and it was done. Real life doesn't happen that way. Any change requires that you get powerful groups and institutions on your side. To do it legally usually requires that you get some important elites on your side: one or more major political parties, the media, the schools, major businesses, etc. You don't necessarily need the majority of the people but it helps to have at least a substantial minority. Having the police and/or the military or other people with guns is also helpful. Radical change is usually best done in small steps. If you announce tomorrow that everyone is to be rounded up and taken to slave labor camps, people are likely to rebel. But if you announce that you are taking away one small freedom, most people will say, I don't like it but it's not worth fighting over. Then take away another, and a few months or years later another. Avoid doing something that will destroy many people's lives all at once. You want people to think that they have too much to lose to risk opposing the government on this. And of course, you don't publicly say, "Our plan is to take away everyone's rights and turn the country into a dictatorship." You say, "We are facing this extreme crisis and so we are calling for these temporary emergency measures until the crisis is over." Or, "We have no choice but to do this extreme thing because our enemies are trying to destroy us and this is the only way to fight back." Or, "Extreme? How are we being extreme? This is plain common sense." Etc. [Answer] As mentioned, the obvious way is to get them to pass a bill. The sneaky way is to outsource so many of the countries activities that, eventually, Parliament becomes a bunch of figureheads with, maybe, slightly more clout than the royal family. Or less clout if the royal family owns/influences those businesses. [Answer] The 1987 movie [RoboCop](https://en.wikipedia.org/wiki/RoboCop) gave a somewhat plausible path to privatizing an otherwise democratic society. In the movie, Omni Consumer Products (the corporation that builds RoboCop) is a private company that has been outsourced to run the Detroit police department. While the movie uses a fair amount of hyperbole, the general implication is that OCP is the de-facto government of the city. The outsourcing of the enforcement of laws allows them to, essentially, do things "above the law". In the United States, Congress has, over the past century, created governmental institutions to create Federal regulations. Examples include the Environmental Protection Agency, the Internal Revenue Service, the Federal Communications Commission, etc. Each agency has the ability to write regulations (essentially laws) and determine enforcement. I'm not as familiar with Britain, but this style of governance is quite popular in modern liberal democracies around the world. If you combined these two concepts, you could create a system that at least still "appears" like democracy (as in there are still elections) but would not actually function like one. Create a governmental agency with the ability to write laws and then have that agency be privatized because only this one company can fill that role. Over time they write laws that make them more and more powerful, while elected officials deflect blame or concerns over those laws (either out of fear or self-interest). Eventually you would wind up with an [oligarchy](https://en.wikipedia.org/wiki/Oligarchy), where the real power is held by this one company running the governmental agency that has taken over all other aspects of the government via regulations. [Answer] The [City of Gurgaon in India](http://reason.com/reasontv/2016/12/15/gurgaon-india-private-city) is probably the most compelling example of how a private company could privatize most of the role of government. It is also relevant of comparable developments in the U.K., because ultimately, India's legal tradition is a direct outgrowth of the British system of government. [Answer] Maybe have a look at the [series of books about Thursday Next](https://en.wikipedia.org/wiki/Thursday_Next) by Jasper Fforde, where the [Goliath corporation](http://www.jasperfforde.com/goliath/aims.html) has achieved something like that. True, the universe there ticks with certain differences (mammoths and time travel to name but a few). The author's imagination is immense. And even if you would not find it inspiring, it's still a great fun to read! [Answer] As I understand the English system it would be a piece of cake. It is sort of a surprise it is not happening, if it is not. <http://www.parliament.uk/about/mps-and-lords/members/electing-mps/> /To become an MP representing a main political party a candidate must be authorised to do so by the party's nominating officer. They must then win the most votes in the constituency./ Obviously this is not the case in the US where any random person with the funds can hold himself or herself out as a candidate and even a candidate of a particular party, the opinions of the parties themselves notwithstanding. Chaotic and disruptive, but definitely democratic. In a system where randoms cannot just stroll in but any candidate must be put forth by the party, then all the company needs to do is quietly take the reins of the party(s) and then put up its own puppet candidates. Badaboom, if they say that in the UK. ]
[Question] [ I'm writing an autobiography of my life in the post-Zed world. Now, I think the effects of the Zeds have been obvious – total obliteration of any worldwide infrastructure, severe depopulation, turning most or all major cities and even smaller ones into zombie-ridden hellscapes. Nowadays, any area with a population over fifty is either very well cleared or doomed. Now, when the zombies emerged and conquered the world, I wasn't there; I was on a small island in the Pacific, starving to death. I only saw the aftermath from after a few months had passed, with zombies still covering the planet and only scattered enclaves. What I do know is this: * They can form packs, sticking together even when there's no immediate prey * They can be affected by just about anything a human can except poison and disease, though they don't feel pain. This means that e.g. tasers work to stun, as would cutting off its arm to kill eventually, and they eventually die of starvation or thirst if they can't find anything to eat or drink. * They can learn basic tasks (climbing stairs, swinging a crowbar, jogging badly) but not complex ones (firing a gun, using a sword well, talking) * They will, on their own, hunt for and scavenge food and water, though they won't share with members of the pack. * They all have pale green skin, and are cooler to the touch than humans (assuming you can touch one without dying!) so they're easy to identify. * They've never been seen to mate, and as far as our scientists can tell, are sterile. If you think I forgot to mention something, feel free to mention it below. Now, my question is this: How did the zombies win? You'd think that humanity would have pretty quickly organized an army and killed the zombies easily, given that we can do things like climb ladders and drive tanks and they can't. What happened? --- Out of character: I'm willing to change some aspects of how zombies work, but I'd much rather use what I've specified here if possible. *If I didn't mention it, feel free to assume it can be whatever you want it to be.* Also, I don't need the zombies to stay alive, I just need the initial devastation. Specifically, I need: * Phone lines, internet, etc. down, though reparable * The power grid disabled/destroyed * Long-distance travel to be hazardous for a few years at minimum * Major cities to be emptied * Most places to be empty of humans, though other life is fine. * Only a (relative) few holdouts left of humanity Anything extra is a bonus. [Answer] This is where the problem is: > > You'd think that humanity would have pretty quickly organized an army and killed the zombies easily > > > If the problem requires large collaboration, beyond the scale that a single organization or nation can handle it, it probably won't happen. It especially won't happen quickly. Most militaries on earth are relatively poorly equipped and even more poorly trained, their soldiers are likely to flee from combat. Unless your zombie outbreak is localized to an industrialized nation with a large army (say, the US) the zombies will overtake them easily. Ordinary human disbelief will give the zombies a lot of time. Media might be reticent to believe in the existence of zombies, even if entire nations have collapsed. Within a country, agencies often don't cooperate. Different branches of a military (or intelligence versus defense organizations) might not want to help each other out. Especially when organizations see themselves as rivals, they will point out how bad of a job the other does - possibly hoping to eventually absorb their functions (and prestige) themselves. Between countries, the politics can be very tricky. On one hand, a zombie outbreak could show that a nation is weak. The country might deny it so that rivals don't see a sign of weakness, and swoop in. A disaster like this can also be a good cover-up for an invasion (How many peacekeepers could the US send to a zombie-infested China?). In short - we are really bad at organizing, even in the face of lethal danger. [Answer] The only way for these zombies (aka infected, rabid humans) to overcome "civilization" is for the virus which causes this sickness to be insanely infectious, and be spread very easily - maybe even by other species, etc. Realistically, it would have to be more infectious than pretty much any other virus we have ever encountered. If it has few symptoms, and a long incubation period (say, a few days) that will help it go unnoticed, and make it that much more dangerous. > > Such a virus could be bio-engineered by a mad scientist (or a stupid, but well meaning one), or maybe it always existed under the thick ice of the Antartica - only now to be unleashed as the ice melts. > > > That way, while the zombies themselves certainly manage to kill a lot of people, the virus will have actually done most of the work, and really get in the way of humanity organizing an armed response. After all, if your soldiers are infected before you even get a chance to organize them into a fighting force the zombies have already won. The effects of this widespread infection would be devastating: * Power plants would shut down (some might explode, etc.) * All sorts of automated systems would shut down. Phone services? Nope. Internet? You're funny. * Most vehicles rendered useless (gasoline has a "shelf life" of about a year) Without communications the few survivors would likely become very clan-ish, which would further impact the recovery aspect. Eventually, however humanity would come out on top and maybe even rebuild civilization, as your infected humans would starve to death, or succumb to injury, illness, or simply cold weather. [Answer] You dont seem to address the most important factor, transmission. If the virus a combination of the following 1. Is highly contagious 2. Is easy to transmit 3. Can survive outside the host 4. Does not kill the host before it can spread 5. Is difficult to prevent 6. Is difficult to kill 7. Is difficult to detect while spreading (asymptomatic contagious period) then it can easily take over anything it is designed to infect, regardless of what the disease actually causes. If the virus meets these criteria, it's hard to fight it since you aren't always sure who is infected. I assumed direct transmission via food, liquid, kissing, etc. so with enough of a on-set delay after initial infection that people will be far too late to figure out if they're infected before infecting others. It increases the chances of it spreading greatly unless they completely separate the people around infected areas and leave them to die. If it takes a week for it to display symptoms, but you can transmit it a day after contact, by the time patient 0 shows signs, it could already have hit an entire country. To balance out the world a bit afterwards (when you've rejoined them), you can assume some kind of basic medicine has been created that prevents the takeover if taken early enough, which prevents complete annihilation of the survivors, and maybe drugs to tell if a source is contaminated (or to clean it). Another option is genetic immunity, which allows for a very diverse group of survivors, but that also means you'd have to be lucky enough to be one of them when you've returned to civilization unless you also want to use the drugs path or some other method of prevention. This answer doesn't require warfare and makes it easy for the virus to spread. It's just a supervirus where the only option is to kill your race or to try and stop it's spread. Here's how I see it playing out: Wherever you want this infection to start from, that person would become patient 0. Assuming it is highly contagious and it has that asymptomatic contagious period, it should spread easily regardless of location. The result should be that highly populated cities of the nearby area will contract it like crazy. Since these zombies can do basic climbing and can mob together, major cities will have to be emptied due to the sheer number of zombies that will develop and the lack of options for escape. These zombies will need food and should easily wipe out all signs of life nearby, short of plants (which will die afterwards since their ecosystem is destroyed). The zombies don't seem to be particularly dangerous. They just have the basic instincts to survive and understand the power of groups. So they won't be destructive, which leaves facilities operable although abandoned and lacking maintenance. (Phone, internet, radio, transportation, power in general) So this leaves the rest of humanity to hide out. The areas that will survive the best are the ones that could close their own personal borders for long enough and that are isolated enough to avoid being overwhelmed. The combination of isolated and fortified is not common. The best places to find this would be smaller cities that can build walls that are away from the initial outbreak. Now, with power down, communication will probably be limited to direct contact with others. Long distance travel is a huge gamble since it is nearly impossible to gather enough materials for that travel since most animals and plants will be dead. This would require gathering food on the go, and where there is food there are zombies. The zombies can obviously only last so long, so after their lifespans are over it should be safe to travel again, but eating any unknown food is still going to require extreme caution. [Answer] Simply that the zombies are an after-effect of the of a massive, multi-spectrum, coordinated worldwide attack. A few zombies appearing in the modern 1st world would be quickly dealt with, as plenty of individuals have a “zombie plan” and local and national government resources could fairly easily handle small outbreaks, and they have a vested interest in preserving themselves. This might becomes a problem in 3rd and 2nd world where governments might not have as many resources available, but maybe not, I'm not familiar enough to comment. I don’t believe that if it could reasonably happen if it was “just zombies” like the ones you described. They are simply put too vulnerable to things normal humans are (ex being perforated multiple times by a machine gun), and poses none of the advantages (cant effectively use tools). Even a slap-dash effort against them can be effective. The problem is there’s too much ability and too many resources for a coordinated, swift, response. Enter “The Attack;” a massive event orchestrated by parties’ unknown that distracts or otherwise absorbs all the resources that would otherwise be devoted towards the zombies. The spreading of the zombies can even be a part of “The Attack.” If the news is covering all the falling chunks of the moon, and countries are flinging nukes around to deal with invading demons, deadly diseases are purposely released on population centers, and earthquakes and other natural disasters wrack large areas then a few zombies cropping up here and there will probably be missed… and the longer zombies are ignored the bigger of an issue they become. In the “The Attack” scenario you give the zombies the boost they need by distracting and draining the resources that would otherwise be devoted against them, allowing you’re fairly vanilla threat to spread until it’s unmanageable. [Answer] It is an interesting question because I just had a small discussion about how long humans would last in a world that falls apart. Your question is about the zombies, my reply focuses on the humans. Here are a few considerations. In the Netherlands where I live we don't have easy access to firearms. We depend on the police and armed forces to protect us. So if the police and army can't cope because they are spread to thin, who is going to protect us? People might perhaps resort to tools converted to melee weapons, but fighting up close with a relentless zombie is something few would be able to do, especially if it happens to be someone you knew or even loved. Another consideration is our food and fuel supply. Most of the supermarkets are stocked on a daily basis. This system will likely break down early on. What food is left will not last long, most of it will have gone bad after a month. So it is likely that in a months time famine will be a common thing weakening survivors and hit double hard because we are not used to hunger. Now imagine a world where you lack food. What could you do? You could try and grow your own. And where would you do that? On large open fields that are hard to defend against roaming zombie groups. This breakdown will hit the health services, the water supply and the sewer system too. All these common services break down if not regularly maintained. Add to it corpses littering the street(and the water supply and sewers!) and disease will be much more common. And we in the west aren't used to illness. Then next we will suffer from the lack of energy. In the winter we would be dependent on wood and such to keep us warm. But our country is mostly deforested. So next to hunger, illness we will be exposed to cold and rain. Even worse for my country is that we are dependent on a well operated draining system. If the water isn't pumped out on a regular basis it will rise several meters and flood a sizable part of the country. I think some country might also be dependent on such services that we aren't aware of but are crucial. When food, clean water, medicine, fuel are in sort supply what usually happens is that they become very expensive and eventually people want to control these and thus eventually start to fight over it. Hence the best ally for the zombies would actually be humans fighting among each other over the scarce resources. The zombies will not need to not win in open combat. They win because their presence makes it harder to get the things people need to live simply by being there. And the humans take care of the rest. :P [Answer] The biggest issue with your plan is "...they eventually die of starvation or thirst if they can't find anything to eat or drink." If you remove that your zombies stand a chance. The issue with starvation is that it makes the zombies part of an ecosystem. Zombies cannot exist without a supply of non-zombie foodstuffs or they die. This means there are non-zombies around to feed from. We are far more dense, population wise, than can be supported without a tremendous network of food shipments. The traditional zombie tends not to be dependent on foodstuffs, so their numbers accumulate as people become zombies. They certainly do seem to enjoy tearing people apart and either eating them or messily pretending they're eating them in front of cameras because you couldn't pay them enough to swallow the sfx gore! The terrifying part of zombie films is that, while any one zombie might be easily dispatched, zombiekind is virtually impossible to annihilate, and it is negatively affecting humans, preventing coexistence. As Chris G points out, infectious transmission can help make these zombies a reality, especially if they don't starve fast. [Answer] There's a point of critical mass beyond which the thin blue line turns into a thin brown streak, the police know this, "policing by consent" as we have in the UK often depends on people not working this out, it's well known that very few of our coppers are armed. This applies to normal people, never mind zombies. If you release a zombie into the morning rush hour crowds at Oxford Circus, it's all over. You've passed critical mass in minutes, the city is as good as lost. I'm sure there's an equivalent point in every western city, somewhere people can barely move except with the flow of the crowds. With respect to getting the army in: Our army is in Germany. It's a long story but the army never left Germany after WWII. What's not in Germany is in Salisbury Plain. By the time either of these groups gets to a big city there probably won't be any survivors to speak of, by the time they manage to get over their years of training to shoot at people who are ostensibly civilians, they're going to have a good few casualties of their own and now they have to shoot their friends. Also there aren't actually all that many of them compared to the 60 million zombies wandering around and they're certainly not carrying that much ammo. Infrastructure will collapse due to lack of maintenance and power, it could be brought back up with suitable expertise but that's going to take a while. In terms of most places being empty of life, this may or may not be true. You could have a Chernobyl/Pripyat situation where nature takes over. The animals run wild, dogs and cats revert to being hunters, the wolves and wild boar move back in, the cows run wild. These animals would have no trouble evading a pack of slow moving human hunters in the wild. Is the zombie plague infectious to animals? If a pack of feral dogs started bringing down zombies for meat would they be affected? How long would it take cougars/leopards/lions/tigers/wolves/wild dogs/hyenas to start chowing down on this slow moving meat with no survival instincts? If they're unaffected then you'd get a massive global surge in predator numbers and they're going to consider people to be food. How's that for making travel dangerous. ]
[Question] [ In my story, there is an Earth-sized planet orbiting a red dwarf, tidally locked to its parent star, with large oceans like Earth, two moons similar to ours and a thick atmosphere to distribute heat around the planet. On the dark side of the planet there are two small continents, each about the size of Greenland, as well as other smaller islands. Now, I've been wondering, would it be possible for plant life to exist on the dark side of the planet? I mean, considering that the planet doesn't rotate, then obviously plants on the dark side can't photosynthesize, but what about the sunlight bouncing off from the moons surface. Could that be enough sunlight for anything to grow? And if plant life could exist on the dark side what would it be like? Considering the fact that even though the atmosphere does distribute heat around the planet, the dark side is still slightly colder. [Answer] Photosynthesizing plants will have serious troubles and are already well covered by the other answers. But what about other kinds of plants? Life is not limited to using the sun as a power source (it just happens to be most abundant one on earth, so most organisms using it easily outcompete others in ecological niches where sunlight is available) - many bacteria can live off hydrogen or other [electron rich elements](https://en.wikipedia.org/wiki/Lithotroph) (sulfur or elemental metals). Traditionally higher organisms like us humans, but also plants (or fungi) like to cooperate with microorganisms for [various](https://en.wikipedia.org/wiki/Nitrogen_fixation#Root_nodule_symbioses) [reasons](https://en.wikipedia.org/wiki/Lichen). I see no reason why some plants that evolved on the day side of your planet (and already had the ability to attract bacteria for symbiosis) couldn't have made it to the dark side and once there establish a symbiosis with microorganisms that can extract energy from non-solar sources. [Answer] Not all plants photosynthetise. [About 1% of all angiosperms are freeloaders](https://en.wikipedia.org/wiki/Parasitic_plant). Your plants might have evolved from regular photosynthetizing plants from back when the planet was not tidally locked. Millions of years in the eternal dark will have caused the ones on the dark side to evolve an absence of chlorophyll. Such plants may thrive by parasiting fungi and/or animals. Alternatively, if there is a lifeform on the planet that thinks of itself as intelligent, plants may take advantage of their technology in order to get a light source for photosynthesis: ![SMBC](https://i.stack.imgur.com/NDJ6Y.png) Source: <https://www.smbc-comics.com/comic/mimic> [Answer] One possibility could be wind-powered plants. A tidally locked planet with a stable atmosphere must necessarily have powerful winds transporting heat from the day side to the night side. (Ocean currents can also contribute to the heat transport, but you're still going to have a significant temperature differential between the two sides, which is going to generate winds.) A plant growing near the terminator could supplement the meager sunlight available there by extracting energy from the wind, and once such a mechanism evolved to be sufficiently efficient, it could even allow those plants to grow without any sunlight at all. What would such plants look like? I'd imagine a primitive (or simply convervative) form might look like a tree with leaves that flutter in the wind, just like they do on trees here on Earth. The differences would be at the cellular level, where the hypothetical wind-trees would have some way of converting mechanical oscillation into chemical energy — perhaps by using the alternating compression and decompression of their cells to drive an [ion pump](https://en.wikipedia.org/wiki/Ion_transporter) and create an ion concentration gradient across the cellular membrane, which they could then use to drive chemical reactions (like [ATP synthesis](https://en.wikipedia.org/wiki/ATP_synthase) in an Earth-like biochemistry). All of this seems perfectly doable using little more than standard Earth biochemical building blocks. The fact that no plants on Earth have evolved to exploit this power source is probably due to the combination of insufficient selection pressure (there being few places on Earth with lots of wind and little sunlight) and simple lack of time for evolution to explore this particular corner of the fitness landscape. Of course, once a plant on our hypothetical planet becomes fully wind-powered and fully loses its dependency on sunlight, there's likely to be lots of rapid morphological evolution and divergence as the descendants of these plants spread and adapt to their new niche. For one thing, these "plants" would most likely lose their photosynthetic capability entirely — it's complex, expensive to maintain and useless on the dark side. This in turn will free their leaf morphology to evolve to fully maximize wind capture efficiency, with no constraints on having to also collect sunlight. So I'm imagining something like tall rigid masts rising up into the windstream, with pale white banners fluttering behind them like sails on a boat turning into the wind. Or perhaps the semi-rigid stems could themselves be the vibrating elements, like giant cat's whiskers standing upright and humming in the wind. Or perhaps some varieties could look like long streamers, anchored to a suitable terrain outcrop (or to another plant!) at one end, with the rest of the plant just freely fluttering in the wind behind it. What I don't really expect to see would be rotors of any kind: while efficient at capturing wind energy, they'd necessitate the evolution of a freely rotating biological axle, something that evolution on Earth never seems to have managed. If such a mechanism did evolve, the rotating part would likely be fully composed of dead tissue — the rotors would grow while still attached to the main plant, then harden and detach so that they can start rotating. But I'd still find a purely vibrational ("fluttering") mechanism more likely. Also, while I've been imagining all this evolution occurring on land, there's really no reason why it couldn't happen underwater as well. Actually, now I'm wondering why it apparently has never happened that way on Earth, given that there are surely lots of places underwater with plenty of currents but very little light. Perhaps it's just the difficulty of converting the existing photosynthetic machinery over to a new energy source, coupled with the fact that this source can really only be efficiently exploited by multicellular organisms (which tend to have longer generation times, and consequently slower evolution, than unicellular microbes) with advanced materials like cellulose to stiffen their structure (which, on evolutionary timescales, have only appeared relatively recently). [Answer] The dark side honeymoon hideaway! 1. Bright moon. Here is a question about a bright moon driving photosynthesis. [Nocturnal Photosynthesis](https://worldbuilding.stackexchange.com/questions/153351/nocturnal-photosynthesis) In my answer I used data from cave plants fed by artificial lights. Your moonlight needs to be 100x brighter than on our world. I humbly propose metallic, reflective moons, one silver and one golden. Aesthetics, you know. 2. Coldness. Yes the dark side will be cold. But maybe you can compensate with internal heat! Your oceans are warmed from below with geothermal fires. They steam and sometimes bubble in the light of the gold and silver moons. Places close enough to the ocean to be warmed by steam will be good places for plants. But as you climb in altitude it gets very cold. And snowy - the steam falls as snow and produces glaciers which gradually push their way downslope back into the oceanic hot tub. A great place for a ski vacation! [Answer] It's possible, but complicated, and probably limited to very simple things at best. The first thing to keep in mind is that tidally locked planets are going to have crazy weather, due to the massive energy differential in the atmosphere. I'd expect strong winds to be common, especially around the more temperate transition zone where you'd expect life to concentrate. While the hot winds will keep the dark side warmer than it would otherwise be, it will still be extremely cold - think the months-long Antarctic nights on Earth for an idea of how cold. If the oceans flow freely between the light and dark sides, they would also have strong currents powered by the huge energy difference, but the precise geography would determine how much this can warm the dark side. Plants on Earth absorb light within specific wavelengths, mostly but not exclusively red. The star will be emitting more in the red, but that has to get to the plants to be used. For the moon to do this, it needs a very high albedo, and to reflect in wavelengths that the plants can use. It's possible for the plants to be adapted for different wavelengths, so color doesn't have to be an issue, but the moon needs to be extremely bright. The closer to the planet, the better, but beware how its gravity and orbit would affect the planet (could it even orbit like this, or would it need to also be tidally locked? If so, would the planet not block most of the light?) Even with all that, supplementary lighting would be helpful, if you want more than the sorts of lichens and such we find in Antarctica. You could add other light-sources, such as nearby gas-giants. If the setting allows for it, orbiting mirrors could be used to focus more light on the dark side of the planet. Artificial lights and greenhouses would also help. Realistically, though, getting anything more than Antarctic levels of growth on the dark side would be very difficult. The closer to the transition zone, the better, just because it would be warmer there, but you're still looking at mostly mosses and lichens, or setting-appropriate analogs. [Answer] On Earth, Fungi are not plants (nor animals. They're a third major branch of the tree of life). Before modern understanding of DNA it used to be thought that fungi were plants that first became parasitic on other plants, and then lost the ability to photosynthesize because they no longer needed it. Finally, they evolved the ability to live off the bodies of dead plants, as well as parasitizing live ones. Elsewhere, this may be exactly what happened. On the dark side, are plant-fungi, getting their energy from stuff brought in on ocean currents such as driftwood. They'll be found in a thin zone close to the shore (no further than their roots / hyphae can stretch). It's also possible for life to use geothermal energy, such as the life on Earth around deep volcanic vents "black smokers". Again, elsewhere, this may be evolved from plants rather than animals. [Answer] I am afraid your main problem will be the low temperatures. Lunar light is sufficient to have a visible effect on vegetation (the old school farmers knew that seeds grew better with rising moon, but not because the rise influenced the growth, as they believed, but because of the additional dose of photons supplied by the moon), however the temperatures staying on the low side will severely affect the growth of any plant. With the right conditions you might get some moss or lichens to grow, but nothing more, I am afraid. [Answer] Carnivorous Plants We have them here on Earth. Sure, Venus Fly-Traps, Pitcher Plants, and the like still rely on photosynthesis in addition to their steady diet of insects, spiders, and small birds, but had they evolved on a world without a regular source of sunlight, they might have become more specialized at catching and digesting unwary animals for nutrition, possibly becoming large enough to even pose a danger to humans (or whatever other sapient race(s) inhabit your planet). It's possible that on the borders of the dark side you'd see some less dangerous carnivorous plants, since they still have some access to light at certain times of the year, but on the full-dark side, it would be truly perilous for adventurers to tread - the less light the plants get, the more they rely on meat to survive, so the more vicious they become. This would especially be a problem for any animal that relies on eyesight to identify potential threats, as they'd be effectively blind on the dark side. [Answer] Why not plants that can use the radioactive decay to power photosynthesis? (see [this](https://worldbuilding.stackexchange.com/a/96542/60215) great answer for the chemical feasibility) Since the planet is tidally locked, the tidal heating could cause strong volcanic activity. These magma hotspots could provide heath (still necessary for the plant in order not to freeze) and a steady flow of radioactive elements to the surface. Plants could then grow and activate photosynthesis thanks to the gamma radiation from these elements. Regarding the evolutive path, the best explanation is that some plants near volcanoes in the dusk zone (the part of the planet in the transition zone from day to night) developed a mutation that allowed their leaves to exploit the gamma radiation (directly, or through a scintillator layer, that is a substance that can convert gamma photons to visible-wavelenght photons). Such a mutation would be very advantageous, since it allowed them to colonize the dark side of the planet. They could indeed spread their seeds in the atmosphere (exploiting the strong winds), so that the ones landing near another volcano could germinate and slowly colonize the dark zone. [Answer] If there is life on the hot side then the cold side will be kilometer thick ice, unless it's ammonia based it simply can't exist. If there is no life on the hot side because it's way too hot then there should be enough convective flow for infrared photosynthesis, or normal photosynthesis by leaves being coated in an infrared up-conversion oil. The answer that mentioned wind power is awesome. If hot enough on the hot side, then said world would also deal with lethal levels of ionizing radiation in regular bursts. I assume evolution occurs inbetween the temperature extremes using normal photosynthesis, but transitions to infrared as it approaches the colder side until the entire cold side is functional, but still above waters freezing point unless using ammonia based biochemistry, which would be slower but would also require less energy and is in my opinion more plausible for such a scenario. [Answer] I would make it a staged energy economy for the plants. First phase.. the food is transported there from the energy rich site.. by energy rich things (seeds, plant byproducts (leafs) and decaying matter byproduct (methane etc.)) or the longterm byproducts oil, coal etc transported there by plate tectonics. Now there is energy there.. How can it be harvested by plant life? Roots and animals that bring the food to the plant for transformation (ants). Which either happens directly (chemical mechanism) or indirectly (the fuel is burned and the plants harvest the infrared). However you look at it, the resulting plantlife looks nothing like we expect it. PS: If the planet has auroras, they could at least have neon-lights up there in the atmosphere.. ]
[Question] [ My world - basically Earth all along, unless told otherwise - is populated by humans and few fantasy-based "races" (actually, species - any interbreed offspring, if possible, is infertile): elves, dwarves, etc. Despite the fact that setting is to some extent inspired by common fantasy tropes, there is no magic at all, just hard science. All "fantasy species" in fact belong to the Homo genus and should be plausibly justified as the effects of natural evolution of (perhaps isolated) groups of hominids. Elves, in addition to some other stereotypical elvish traits (slender, pointy ears etc.) are known to not eat meat of any mammal or bird, while having no problem with milk, eggs, fish and seafood (insects, amphibians and reptiles are a grey zone, read: I have no idea here). Sure, I can come up with some cultural reason for this, but instead I would like to actually hardwire this trait somehow in their biology. Meat of mammals and birds should be just inedible, though, not poisonous or otherwise deadly: I don't want them to die just because they ate some food offered by humans! Why these kinds of meat could be inedible for a hominid? [Answer] Non-metabolizable components in meat proteins accumulate in elves that eat them, causing gradual physical and mental degeneration. Lectins are cell surface glycoproteins. About 150,000 years ago there was an evolutionary bottleneck, from which the ancestors of humans emerged lacking certain lectins that are still present in our ape relatives. I am sorry I could not find full text. An abstract: [Varki A. Glycoconj J. 2009 Apr;26(3):231-45. Epub 2008 Sep 7. Multiple changes in sialic acid biology during human evolution.](https://link.springer.com/article/10.1007%2Fs10719-008-9183-z) > > Humans are genetically very similar to “great apes”, (chimpanzees, > bonobos, gorillas and orangutans), our closest evolutionary relatives. > We have discovered multiple genetic and biochemical differences > between humans and these other hominids, in relation to sialic acids > and in Siglecs (Sia-recognizing Ig superfamily lectins). An > inactivating mutation in the CMAH gene eliminated human expression of > N-glycolylneuraminic acid (Neu5Gc) a major sialic acid in “great > apes”. Additional human-specific changes have been found, affecting at > least 10 of the <60 genes known to be involved in the biology of > sialic acids. There are potential implications for unique features of > humans, as well as for human susceptibility or resistance to disease. > Additionally, metabolic incorporation of Neu5Gc from animal-derived > materials occurs into biotherapeutic molecules and cellular > preparations - and into human tissues from dietary sources, > particularly red meat and milk products. As humans also have varying > and sometime high levels of circulating anti-Neu5Gc antibodies, there > are implications for biotechnology products, and for some human > diseases associated with chronic inflammation. > > > Evolutionary divergence events in hominids are associated with shuffling of the glycoprotein repertoire. There are mutations in humans in which the afflicted cannot metabolize certain glycoproteins. Two are the [mucopolysaccharidoses](https://en.wikipedia.org/wiki/Mucopolysaccharidosis). Examples are [Hunter's syndrome](https://en.wikipedia.org/wiki/Hunter_syndrome) and [Hurler syndrome](https://en.wikipedia.org/wiki/Hurler_syndrome). The accumulation of the glycoproteins in the body tissue produces characteristic deformities and developmental defects. I will not link images of the kids affected by these syndromes but they look different in a manner characteristic of their disease. Another name for Hurler syndrome is gargoylism. So your elves: the divergence event that led them to speciate involved a loss of certain glycoproteins, and then also the metabolic capacity to handle these glycoproteins. Just as Neu5GC is in our meat animals but not in us, these glycoproteins are in other mammals, but not elves. When the elves ingest them (just as when human ingest beef) these now-foreign molecules persist in the body (as Neu5GC from meat persists in our bodies). A little bit is ok, but over weeks and months these substances accumulate, causing mucopolysaccharidosis- like physical deformities and mental disease in the elves who eat them. And they know now not to eat them. This is more interesting, I think that just dropping dead if you eat a meatball. Elves in dire straits could eat some meat. They might even like it; probably they would. But a steady diet of meat will become obvious as the meat eating elf will become thicker featured and less sharp of mind... --- In fact, there would be one terrestrial vertebrate whose meat these elves could eat with impunity. Perhaps this would be done for certain ceremonies. Deducing the identity of this animal is left as an exercise for the reader. [Answer] Red/mammals meat differs from fish meat essentially because of its different content of fats. You can have your elves lack the enzymes needed to digest highly saturated and/or aromatic fats (cholesterol). That would be enough to give them good reasons to routinely avoid the stuff without preventing occasional usage. Occasional intake would mostly go unnoticed, but continue would result in diarrhea. [Answer] I can't think of a way to hardware it into their genetic code, but it is possible to be allergic to red meat and poultry. (<http://acaai.org/allergies/types/food-allergies/types-food-allergy/meat-allergy>) Basically, if someone is bitten by the Lone Star Tick, they can develop an anaphylactic response to eating red meat. If there was something like this in their environment, and became widespread in their population, it could result in a culture wide aversion to eating red meat. However, if you're worried about death by meat allergy, you could have the elves only develop the more minor symptoms of the allergy. That way eating meat would make them uncomfortable, rather than potentially killing them. [Answer] One approach would be to look at what diseases are more common in pescatarians or ovo-lacto vegetarians, in humans, and then make your elves prone to the opposite of those diseases. For instance, anemia sometimes occurs when someone switches to a vegetarian diet, due to insufficient iron intake. The opposite condition appears to be called [hemochromatosis](https://en.wikipedia.org/wiki/Iron_overload), where there is too much iron in the body. A predisposition towards hemochromatosis (such as if their body were more efficient at concentrating/utilizing dietary iron) would discourage elves from eating too much red meat - a little bit might be fine, but if they ate it regularly, they'd feel chronically unwell. If you were to use that approach, there could be some related dietary impacts, as well. For instance, a species which needs a lower-iron diet might eat less spinach than humans do, and would likely avoid foods such as [marmite](https://en.wikipedia.org/wiki/Marmite#Nutritional_information) (despite being vegetarian-friendly for humans). For bird meat, I'm not sure what exactly could cause selective dietary problems. There may be some other nutrient that the elves could be unable to handle in large quantities; or perhaps they eat all lower-iron meats, but not high-iron meat (beef, apparently chicken liver, etc.). [Answer] the problem hear is there is nothing completely unique to mammal and bird meat. that is there is nothing present in all mammals and birds that is not present in things like eggs, shellfish, dairy, or many plant based foods. The closest I think you can get is to make them a mild food allergy for myoglobin, it is at least unique to vertebrates but the amount varies quite a bit. It can't be too strong an allergy since they have myoglobin in their own muscles. Myoglobin is present in large amounts in most birds and most mammals muscle tissue. It is present in many other animals as well but the levels are very high in those two groups. Red meat is very high in myoglobin, and is linked to several meat allergies (like beef allergies), your elves will still be able to eat (most)fish just fine and a few low myoglobin mammal and bird meats (for instance opossum meat and poultry white meat is very low). But most mammal and bird meats will elicit a reaction. Myoglobin is only present in muscle tissue so there will not be any in eggs or dairy. So some rare poultry and mammal meats will be edible but many/most will not. But you could easily make this reaction to most mammal and bird meats a basis for a general psychological aversion to mammal and bird meat in general. If eating any meat becomes a gamble they could easily develop a taboo against terrestrial meat in general. note there are a few fish that are high in myoglobin, so no red tuna for your elves. They may start avoiding any red fish meat as well, this is rare at least so they may still see other fish as perfectly edible. [Answer] You could make it so that eating seafood is a necessary dietary constraint. So rather than having the elves avoid eating other land-based meats, they have evolved to where certain required nutrients are only found in seafood. For example, humans require vitamin C in their diets, but other mammals typically do not. This is because while vitamin C is required for most/all mammals, most of them can manufacture their own. Humans, however, lost that ability some time ago, but this defect persisted (rather than killing off those with the bad gene) because of an abundance of food with vitamin C in the area where they lived. It only became a problem when humans moved out of the tropics and started taking long voyages without adequate vitamin C laden foods. So your elves may have evolved in an area where they anciently ate mostly fish, and their bodies mutated leaving them dependent on some nutrient in the fish. They now need to regularly eat fish, rather than red meat or poultry, thus they would be primarily pescatarian. This would not mean that the other meats would be poisonous, just that over time the elves would not be able to survive on only land meats. [Answer] Teeth Other suggestions delve in biochemistry, but I can suggest an anatomy way: they lack "meat" teeth. We, humans of this world, have sharp, "meat" teeth in front and flat, grinding "plant" teeth on sides. This allows us to chew everything. If elves have only flat teeth, or may be even soft teeth, like wales do, it will be a real chore to bite off and chew meat due to its consistency. Thus, prehistoric elves avoided it altogether, and nowadays they can technically cook it edible, but meat is just not in their culture. [Answer] Evolution works by killing fertile individuals before they reproduce. Harsh, but simple to consider. Now your stereotypical elf doesn't have kids at a young age - they have a long lifespan after all, and your world doesn't suffer from massive overpopulation. So fertility must be fairly low. Perhaps they get kids at age 200-300. This means that anything which kills them in <200 years is evolutionary bad and selected against. Now, if consuming red meat causes heart attacks in 150 years, the ability to eat and process red meat would be a clear disadvantage. Those elves that digested red meat less well would have a larger chance of survival. TL:DR: Red meat kills elves before they have offspring, driving evolution. [Answer] I'd say something psychological. Elves, in fiction, are known for their love of nature and such. If they eat something that came from a sentient being, it's possible that they start breaking out in hives, or become sick, not because they have a species-wide allergy, but because of their culture. [Answer] I'd say make their genetic history favor not eating meat, maybe it's not very good for the elves. Meat would therefore taste bad for elves. They would still be able to eat it, somewhat. I wouldn't go for the route where it's entirely inedible, but that's just me. ]
[Question] [ In my world spaceships are guided by lighthouses floating in space instead of electronic navigational systems. A lighthouse in space has the shape of a huge sphere emitting intense red light. Like the ordinary lighthouse a space lighthouse mark dangerous things, such as : black holes, supernovas … They also mark space stations, docking bays, fuel stations and other things. My questions are: 1. Is this system viable? 2. Is this scientifically possible? 3. How much surface should a sphere (lighthouse) have, in order to emit enough red light? [Answer] > > 1 - Is this system viable ? > > > It is breathtakingly inefficient. > > 2 - Is this scientifically possible ? > > > Yes, the question is if you can get enough power to make it worth the trouble. > > 3 - How much surface should a sphere (lighthouse) have, in order to emit enough red light? > > > It's not surface, it's power. Because you're omni-direction you'll need a lot of it. Basically you need a star. --- The problem is making this thing bright enough to be noticed far enough away so fast-moving spaceships have time to make course corrections with minimal [delta-V](https://en.wikipedia.org/wiki/Delta-v). I'm going to use some relatively small numbers for time and velocity by sci-fi standards to give this the best chance of working before trying to scale up. A spaceship going 1% the speed of light is moving about 1010 (10 billion) m/h. If we want to give this ship one hour of warning (probably not enough time, but we're starting small) *it needs to see the beacon 10 billion meters out. This might seem far, but [it's only 1/5th the distance from Earth to Mars at their closest](http://www.universetoday.com/14824/distance-from-earth-to-mars/). Not even interplanetary scales. First, using visible light means you're competing with everything else that's producing visible light: stars and everything reflecting starlight. It's like turning on a flashlight on a sunny day, can't see it. An omni-directional lighthouse is just a radio transmitter. Visible light is a crowded part of the spectrum, so you can do a little better by changing to a less common frequency probably in the [Microwave Window](http://www.setileague.org/general/waterhol.htm). No human is going to eyeball this thing anyway, it'll all be done with computers just like a radio. So pick a rare frequency. However, the higher the frequency the more energy required, so pick something low. Transmitting in an uncrowded, low frequency, part of the spectrum will significantly reduce the required energy. Pulsing it in a recognizable sequence will help picking it out of background noise. But here's the problem: because this is an omni-direction beacon you can think of its energy racing outwards in an expanding sphere. The surface area of a sphere increases with the square of its radius, spreading the energy thinner and thinner. Double the distance from the lighthouse, quarter the energy. If it has 1000 [lux](https://en.wikipedia.org/wiki/Lux) at 1 m, at 2 m it will have just 250. At 4 m it will be down to 62.5 lux. At 10 m it's just 10 lux. A sphere 10 billion meters in radius has a surface area 1020 m2 times larger than one with 1 meter radius. A light source you can spot at 1 meter needs to be 1020 times brighter to be seen at 10 billion meters. And therein lies the problem: power. That's a lot of power. And it's for a relatively slow spaceship with relatively short warning. At a certain point you might as well just create a small star. To put this in concrete terms, for your beacon to be [as bright as Sirius it would have to be as bright as light bulb at 1.6x104 m](http://www.wolframalpha.com/input/?i=apparent+magnitude+sirius). A light bulb puts out about 103 or 1000 [lumens](https://en.wikipedia.org/wiki/Lumen_%28unit%29). To be that bright at 10 billion meters out, 6.25x105 time further away, you'd need to increase with the square of the distance: 3.9x1011 or 400 billion times brighter than light bulb: 6.25x1015 lumens. This is [six orders of magnitude larger than the largest spotlight in the world](https://en.wikipedia.org/wiki/Luxor_Las_Vegas#Luxor_Sky_Beam), though still nine orders below the smallest red dwarf. That's the lower bound to be seen 1 hour away by a ship going at 1% the speed of light. We're not even into interplanetary scales, much less interstellar ones. Double the speed or reaction time, quadruple the brightness required. --- Unless you have the power of a star, omni-directional transmission doesn't work at interstellar or even interplanetary scales. You need something directional. The problem for a directional beacon is to work out where to point it. [Answer] 1. Sort of. 2. Yes 3. This would depend on how bright the light is, total radiation is surface area \ brightness so to make it more visible you can increase either. It would certainly help make things easier to see, but the thing is space is really big and empty. There isn't much to run into and it's generally easy enough to avoid the things that are there (or you need to go to them anyway). Navigation can't really be done by eye in space since you're dealing with orbital dynamics and transfer orbits and all sorts of other very complicated maths. Most of the time in space with current or near-future tech you aren't even using your engines. You just use them occasionally to accelerate/correct course/decelerate and spend the rest of the time coasting. A super-nova would be far more visible than your floating red sphere. Even a black hole is surrounded by an accretion disk and highly visible most of the time. If you had an isolated black hole or neutron star then you might possibly be able to argue for some sort of warning beacon but it still doesn't make a lot of sense since you would need to account for the gravity from the neutron star/black hole when navigating and if you didn't know about it would detect it by the changes to your course it generated long before impact became a risk. [Answer] > > 1 - Is this system viable ? > > > I think the buck stops here, really. No, it's not viable. What you are proposing is perhaps "possible" in some limited sense (but as already pointed out by others, you are up against some very fierce competition in terms of light sources). It isn't however viable. This isn't for reasons of the amount of light you would need to put out. Throw sufficient amounts of handwavium at that, and you could explain it away, or just [lampshade](http://tvtropes.org/pmwiki/pmwiki.php/Main/LampshadeHanging) (pun only half intended) the whole problem. The reason is spelled orbital mechanics combined with the finite speed of both light and space travel. If we assume space travel by Newtonian or relativistic mechanics as currently understood (which would be an implied requirement, since you are asking for answers based in known science), then we are limited by the laws of orbital mechanics. Basically, spacecraft coast for all but a tiny fraction of their travel time. Practical spacecraft have very limited [delta-v](https://en.wikipedia.org/wiki/Delta-v) budget (ability to alter their velocity and vector) due to [the tyranny of the rocket equation](https://worldbuilding.stackexchange.com/a/30096/29). In order to reduce the delta-v required for a particular position change after some amount of time, you need to increase the time between the maneuver and the time at which the position change needs to be completed. The earlier you can perform a maneuver, the less fuel you need to get the result you want. Compare the fact that in order to land, from an orbital velocity of on the order of 7-8 km/s, [the space shuttle only needed to reduce its velocity by about 100 m/s under power](https://space.stackexchange.com/q/12011/415) before gravity and drag did the rest. Objects in space generally refuse to stay put. If you take your fancy spacecraft into a low Earth orbit, park and [lock the doors](https://space.stackexchange.com/q/2387/415) when you go for an EVA to grab a [lunch](http://physics.ucsd.edu/do-the-math/2011/10/why-not-space/), and look for the spacecraft about 45 minutes later, you will find it on the other side of the world. (Thankfully, you will also be on the other side of the world, which somewhat reduces the practical impact of this.) Geosynchronous orbits don't help, because you are still moving at orbital velocities; you just happen to have an orbital velocity that matches the angular velocity of the rotation of the planet beneath you (the point directly to your nadir). [Lagrangian points](https://en.wikipedia.org/wiki/Lagrangian_point) don't help either, because as the relevant objects move those points move as well, which means you (in this case, the light source) is moving with them. Let's say you can somehow engineer a light source that is bright enough to be possible to make out at the distance between Earth and Pluto when the two are at opposition (points farthest from each other), and we put it roughly where Pluto is in our universe. Pluto's orbit reaches out to about 49 AU from the Sun, and the Earth orbits at about 1 AU from the Sun. So we want something that is visible at 50 AU. (Pluto's orbit is in a different plane than the rest of the solar system, but for an example, this works anyway.) 50 AU really isn't far at all in terms of interstellar travel, which I take it you are concerned with because of the dangerous objects you mention in your question, but it works nicely once you approach a solar system. Now, let's say your ships travel at 1% of the speed of light, or 3,000 km/s, relative to the light source. (This is far, far faster than anything we can accomplish with chemical rockets, but it is still somewhat within the realm of possibility with science and technology as we know them.) 50 AU is about 7500 Gm, so this distance will take your spacecraft about 2.5 million seconds to travel. (Back-of-the-envelope plausibility check: speed of light time delay from the Sun to Pluto, on the order of 7 hours. Speed of travel, 1/100 of the speed of light. Expected travel time, 700 hours. 700 hours is 2.52 million seconds. Check.) Pluto's orbital speed averages about 4.67 km/s. In those 2.5 million seconds that the light needs to reach our intrepid spacecraft 50 AU away, Pluto (or our light source) moves almost 11.7 million km along its orbit. This is before the crew of the spacecraft even sees the light. [Spacecraft generally travel along elliptical transfer orbits](https://space.stackexchange.com/q/7981/415) selected to get it to some particular point in space at some particular time (usually at a time when an object of interest is going to, in its orbit, intersect that point, or a point near that one) within some given constraints (time, delta-v, payload mass, ...). Any time a spacecraft is going anywhere, it is doing so by assuming a transfer orbit (very often a [Hohmann transfer orbit](https://en.wikipedia.org/wiki/Hohmann_transfer_orbit), which in many cases is the lowest-energy way we know of to get from point A to point B in space; another alternative sometimes considered is a [bi-elliptic transfer orbit](https://en.wikipedia.org/wiki/Bi-elliptic_transfer)). In Hohmann transfer orbits, you basically trade time for delta-v; the more delta-v you can afford, the more direct a route you can take and the quicker you can get to your destination. Since as we saw above that we want to minimize the delta-v expenditure in order to reduce our spacecraft's mass ratio, this means that we need more time to get to where we are going than if we were travelling in a straight line. So not only has the light source already moved over ten million km along its orbit by the time the light reaches the spacecraft at 50 AU away from the light source's original position, but you also have to consider how long the spacecraft will need to get to where the light source (or point of interest) is now. (And that's "now" in which reference frame?) And by the time you get there, where is the point of interest going to be then? It's a variation of the classic math trick question of halving something repeatedly: $$ x + \frac{x}{2} + \frac{x}{4} + \cdots + \frac{x}{n} $$ This is exactly the type of problem humans are horrible at solving, and computers are excellent at solving. Which is why anyone who wants something even remotely like this would be far more likely to use radio beacons and electronic computers than navigation by eyesight and estimation. The type of light (or even EM) source you are using has no effect on this, because the problem is related not to the type of EM source but rather to the relative speeds of the objects involved, and orbital mechanics. [Answer] Apart from all the other things mentioned in other answers, there are some more relevant issues: 1. Lighthouses have to be kept in place relative to the thing they are marking. Not really an issue on earth, when marking rocks, harbour entrances etc; they don't move much, and they don't affect lighthouses. Supernova, black holes and the like, all have gravity. This will move the "lighthouse" around. In practice, the lighthouse would probably need to be in orbit - pretty much everything smaller than a galaxy, tends to be in orbit - the moon orbits the earth, earth orbits the sun, the sun (and solar system as a whole) orbits the center of our galaxy (our galaxy is the Milky Way). 2. If you are coming from the wrong direction, the object being marked will obscure the lighthouse. Lighthouses work great at sea, where nothing sticks up. They work ok on the coast - if you're coming from the land side, you probably don't need the lighthouse, and lighthouses are usually at the highest point, to shine above anything that might obscure it. In space, one person's up is another person's down, and if you are unlucky enough to approach from the wrong side, that lighthouse you are looking for may be behind the object. 3. Very massive objects can bend light. This applies primarily to black holes. Similar to mirages on earth, the light from a "lighthouse" (or, for that matter, radio signals) will bend around a sufficiently heavy object, making it appear in the wrong place, distorted, or different colour and/or brightness. See "[Gravitational Lensing](https://en.wikipedia.org/wiki/Gravitational_lens)" 4. Light is the same thing as radio. If this is for alien (from our perspective) beings, then be aware that light and radio are the same thing. We humans have taken a small piece of the radio spectrum, and said "that bit there is different from the rest, because we can see it". Alien beings may say the same thing about other frequencies. Or they may sense their environment in a completely different way. Similarly, if your radio could be tuned up from it's usual 91.5 MHZ to around 480 million MHZ (480 terrahertz), you would be tuned to red light. Snakes can see infrared (for a given value of "see" - they don't sense it through their eyes, but it does go through the "vision" areas of their brains), which seems "black" to us. 5. Red means "Danger" - to us! To other races of the galaxy, red may mean "safety". Beware of cultural assumptions, when working with alien species - your assumptions are bound to be wrong. --- Points 1 & 2 can be solved by putting a number of "lighthouses" in orbit, similar to the GPS satellite "constelation". GPS satellites, for example, are in 3 different orbits, all through the poles; 8 satellites in each orbit, at 120 degree intervals, for a total of 24 satellites, plus a few spares; I would think that 2 per orbit, at opposite sides of the object, for a total of 6, would be enough when seen from space. You might, hypothetically, be able to get away with 2, at opposite sides of the object, though even a small, invisible object could occlude your lighthouse. [Answer] As others have noted, a supernova would be putting out a lot more light than any human-built lighthouse is likely to be capable of. That's like having a guy with a flashlight to warn people away from an erupting volcano. But as some sort of navigational marker in general ... it could work. My immediate reaction is that it would make more sense to be broadcasting a radio signal. That could be distinguished from background noise much more easily. Is it technically possible to build a big red light and put it in orbit? Sure, why not? It's certainly possible to build satellites: humans have built plenty by now. And it's certainly possible to build large lights. How big would it have to be? Depends how much light you want it to put out and how far away you want it to be seen. I don't think there's any formula there. Also, how visible it is will depend on how much energy is being emitted, which might be affected by the size but is not determined by it. A 100 watt light bulb and a 40 watt light bulb are often the same size. I think the bigger question is, How much power will it need, and where will that power come from? [Answer] More than likely they would be emitting something more powerful than red light, but the idea is sound. The Hugh Howey novel *Beacon 23* is based on this idea. In that novel, it's broadcasting the location of a large asteroid field, as that world's FTL travel is similar to Star Wars (physical objects can impact travel due to gravity fields). As for surface area, enough is largely dependent on how far you want it to be seen by. I could definitely see you wanting to mark something dark, like an asteroid field or black hole (emitting something other than Hawking Radiation), or smaller things like the aforementioned docking bays, although something more similar to Range Lights would be better for those.. [Supernovas and similar events are already pretty bright](http://theweek.com/articles/485668/brightest-space-explosion-history) all by their lonesome. [Answer] Have you looked into pulsars? <https://en.wikipedia.org/wiki/Pulsar> There's been some talk about using them as galactic navigation beacons. [Answer] I don't think this would really work. * Wouldn't be useful * Would cost too much energy * There are far better ways to do things However, I like the idea of lighthouses in space. It could lead to some nice visuals. That's something that might be worth preserving even if the notion of using them for navigation isn't practical or useful. Are you proposing faster than light travel? Because space is really, really big. If there's no faster than light travel you don't really have to worry about running into a black hole because it's going to take you thousands of years to get to one. (and if you're traveling faster than light, using light to navigate is not going to work very well-- also the further you dig into FTL the more problems you discover). If you're positing FTL you'll be positing leaving normal space to do it. You go somewhere else, traverse some different distance and then pop out where you're going. Being able to sense some navigation beacon across the boundaries of these two types of space would be necessary. Neither that space nor anything that could penetrate it are known. So invent it ;- ) If it happens to have a nice rosy glow in the visual spectrum? Bonus. In normal space nobody's going to spend the kind of energy needed to make a visible beacon in space. It wouldn't work well, it'd cost way too much energy and there are way better ways to do it. You can avoid hitting rocks by mounting radar on your craft. And things you really need to worry about are traveling so fast that visual cues are kind of useless. Imagine a rock traveling faster than a bullet. It's the size of a golf ball and it comes at you from above. You're not going to see it in time to do anything about it. Radar and a computer will though. Also there's not really much in the way of visual cues when navigating a space ship. Consider the fact that the gravity well functions like a steep slope you can't see. When you "park in orbit" you're really just doing a bunch of math about your speed, direction and placement on a steep slope. You can't see any of that with the naked eye. What might be interesting is a heads up display which DOES show orbital dynamics and hazards visually. Show the gravity well as a lit up slope rolling down towards the planet. You could point out debris or navigation hazards in white light on your face mask or control panel when they're too far away to be able to see with the naked eye. You could represent size and speed with visual cues. The human mind is really well tuned to that. A tool which could present data in that way could be super useful. It also simplifies controls and readouts. ]
[Question] [ In both fiction and non-fiction worlds, that attempt to keep a sense of realism, planets are spherical. Is it possible for a planet to not be shaped like a sphere? If such a planet is possible could it sustain life? For example, having a proper magnetic field, atmosphere, etc? [Answer] It'd be possible for one to exist for a time, but a naturally occurring, non-spheroid planet would be incredibly unlikely. More on that at the end. It's an easy thing to imagine of course, but that's because we think of things like cube shaped rocks that occur naturally and think 'why not?'. The problem is that objects on a planetary scale don't behave the same as boulder or even small moon sized things. Anything above [200-300km radius squishes into a spherical shape](http://physicsworld.com/cws/article/news/2010/apr/20/dwarf-planets-are-not-space-potatoes). [![Shapes: dust, potatoes, spheres, disks, halos](https://i.stack.imgur.com/rBOjx.jpg)](https://i.stack.imgur.com/rBOjx.jpg) [Source](http://physicsworld.com/cws/article/news/2010/apr/20/dwarf-planets-are-not-space-potatoes) So, you can have a space potato that's not a sphere, but it's technically not a planet. It could have an [atmosphere at any size](http://www.pbs.org/wgbh/nova/space/how-to-get-an-atmosphere.html), though it's less likely to hold on to it if there are other large masses nearby or in high solar winds. To have something the size of a planet but not a sphere you'd have to find a planet that has had a terrible accident. If you crash a large moon into a planet you might be able to horribly deform the planet and give it some new moons. Assuming the remaining mass is large enough it could still be defined as a planet (massive enough to collapse into a sphere) but non-spherical. The non-spherical shape would be temporary, hundreds of thousands of years perhaps. As it's just been destroyed it's unlikely to have life though. Edit: What if Earth were a cube? There is an interesting article on that [here](http://news.discovery.com/space/what-if-earth-was-a-cube-110815.htm). Basically the corners and edges of the cube would be like massive mountain ranges, as they would be at an angle with respect to the vector of gravity (except in the center of the faces). I wrote a more detailed answer about such a world [here](https://worldbuilding.stackexchange.com/a/8837/3202). The oceans would move to the centers of the cube faces. Basically, the Earth would look very different. Likely still inhabitable, assuming whatever magic formed it into a cube kept the the shape, otherwise we'd probably all be killed by the planet shaking earthquakes. [Answer] Donut-shaped planets are [indeed possible](http://io9.com/what-would-the-earth-be-like-if-it-was-the-shape-of-a-d-1515700296)! The article cites a paper which concludes that certain kinds of toroidal planets are at least internally stable, although not likely and possibly would get ruined by any external interference. It's true that gravity will make a randomly-shaped blob of matter coalesce into a sphere over time, but there's no reason that it has to do so with a torus. Matter is attracted most strongly to the closest matter. [Answer] Yes, we live on one :-) Strictly speaking, the Earth is not a sphere, it's an oblate spheroid. Its rotation makes it bulge somewhat, so the equatorial radius is ~30 km greater than the polar. A faster rotation would make a planet even more oblate: Saturn's polar & equatorial radii differ by almost 10%: <https://en.wikipedia.org/wiki/Saturn#Physical_characteristics> because the centrifugal force from rotation counterbalances the gravity. Cubes, donuts, &c couldn't exist, though, at least if they're composed of normal matter. It's a matter of strength of materials. The corners of a cube would behave like very tall mountains, and collapse under their own weight. [Answer] The [sphere shape](http://scienceline.ucsb.edu/getkey.php?key=2911) is entirely based on gravity. That is actually one of the parts of the definition of a planet. That is is large enough that it's gravity will make it a sphere. The objects that are not spheres are much smaller or they would have to be artificially created and maintained. (unless shortly after a large event that distorted the planet, like a moon colliding into a planet, but in time it will round itself out again. [Answer] Hard SF writer Hal Clement wrote a delightful book in 1953, Mission of Gravity, which introduced a very physically correct non-spheroidal world, Mesklin. Mesklin, a high-mass planet subject to extreme rotational stress, is shaped like a thin disk with a central bulge. From the [Wikipedia article](http://en.wikipedia.org/wiki/Mesklin): > > "Clement decided, since its mass was 16 times that of Jupiter, Mesklin would have an extremely large angular frequency to partly counter its gravity in order to allow humans to visit part of it. He wanted the equatorial gravity to be 3 g, so he determined the period necessary to make this occur: each Mesklin day is 17.75 minutes long given that the planet rotates approximately 20 degrees a minute. > > As a result of this extremely large rate of spin, Mesklin is not even slightly spherical; it has a large equatorial bulge. Mesklin's equatorial diameter is 48,000 miles (77,250 km), while from pole-to-pole along its axis of rotation it is 19,740 miles (31,770 km). Then Clement attempted to calculate the polar gravity, finding it surprisingly difficult. He admits, "To be perfectly frank, I don't know the exact value of the polar gravity; the planet is so oblate that the usual rule of spheres... would not even be a good approximation..." "Whirligig World" reports his initial calculations of the pole gravity to be 655 g; the dust jacket of Heavy Planet reports it as 700 g. A later program created by Clement computed it as 275 g" > > > This is a much more extreme example of the deformation of Saturn described in jamesqf's answer. Possibly not what you're looking for, but it makes a nice illustration of just how plastic large planets are under the force of gravity and the apparent centrifugal force of spin. [Answer] It's not possible unless the planet is made of unobtainum. If you had, for example, a cube-shaped planet with a liquid center, you would have a huge amount of pressure on the liquid interior of the planet applied by the corners of the cube, which would effectively function like gigantic mountains. This pressure wouldn't exist on the faces of the cube, so the internal pressure would push them outwards, likely resulting in the formation of some absurdly huge volcanoes as the liquid interior of the planet, under the pressure applied by the corner mountains, burst through cracks in the surface of the low-pressure faces of the cube. The corners would sink down and the flat portions would fill up with lava, which would slowly cool into the shape of a sphere. [Answer] What about some planet in orbit around a very heavy black hole? There could be some situations where the stable state of such a system included a non-spherical planet. Also, you could get some interesting relativistic time effects, like in Interstellar. [Answer] One of the defining traits of a planet according to the IAU is that it be in hydrostatic equilibrium. That means it can't be holding its shape against its own gravity which results in an oblate spheroid with at most fairly minor lumps. If you made a planetary scale structure out of super string unobtanium (Rather than something as squishy and flexible as rock) that was not in hydrostatic equilibrium, it technically wouldn't be a planet. Ring worlds, orbitals, and the like are not planets. Unlike the "clear its neighbourhood" requirement (the thing that got Pluto reclassified), no one really disputes this part of the definition of "planet". The spin rate required to get enough oblateness to be significant to anyone other than scientists, engineers, and the like just isn't going to occur in something that fits the definition of a planet naturally. The collapsing dust cloud forming a star and its planets is only going to have so much angular momentum. It's also going to be subject to some crazy tidal forces (which will slow it down) In theory a torus (doughnut shape) can be in hydrostatic equilibrium if it's spinning fast enough. Even if it could get spinning that fast, and get into the torus shape, it wouldn't be stable in the long term. If it got even slightly out of balance it would tear itself apart. The rough version of this is: No, a planet is (to the tolerances of a ordinary person) spherical by definition. Anything not spherical is not a planet. [Answer] I think that a planet is definitely able to be misshapen and still be a planet! Our very own Earth is not a perfect sphere! It is a bumpy oblate spheroid, though it looks like a marble from space. Earth's poles are squashed, and it is swollen at the equator. Because of the bulge, the distance from Earth's center to sea level is roughly 21 kilometers (13 miles) greater at the equator than at the poles. This was all discovered by Issac Newton. Earth has a bit of plasticity that allows the shape to deform slightly. An oblate spheroid is not perfectly correct either, because of the fact that mass is distributed unevenly within Earth, also causing more deforms. [Answer] It is not possible because of gravity, with the spherical shape of our Earth's core, the earth is shaped into a sphere. If there were a donut shaped planet, there would be no place for the core, therefore it wouldn't be classified as a planet. With the hole in the center, the center of gravity wouldn't exist. To be classified as a planet, it has to have a core, and atmosphere, and has to be shaped as a sphere. [Answer] If there was a solar system with two sun's and a planet in-between, if the sun's rotated while the planet was, it might keep the planet in a disklike shape. Or split the planet in half. But that chance is still there. It would look like that one planet from Netflixs Voltron. ]
[Question] [ Everybody loves [steampunk](http://en.wikipedia.org/wiki/Steampunk). Without reading the Wikipedia page, the main idea of steampunk is a world (usually 19th century or thereabouts) where [steam power](http://en.wikipedia.org/wiki/Steam_engine) is used universally, and computers as we know them have not yet been developed, but many of the things that we take for granted (cars, airtravel, sometimes even steam-powered computers) are still there, but are powered by steam instead of whatever we use today. The way I look at it, our world could have been steampunk if the problems we needed (or wanted) solved would not have been solved by the combustion engine and the computer. What would need to happen to the history of science to produce a 21st century steampunk world? * What specific scientific discoveries (if any) would need to be skipped1 in order to have steam remain mainstream? What inventions would need to disappear so that computers would have not taken over the world? * What would need to happen to the history of science and invention to allow a full-blown steampunk world, today? --- 1 Possible story point -- "suppressed" instead of "skipped," allowing for a computer underground in a steampunk world. .....maybe. [Answer] What inventions would need to have never happened? Transistors and the Internal Combustion Engine. You say "computers have not yet been developed... computers are still there" The only reason electronic circuits are so compact is transistors and nearly everything depends on them. It is entirely possible to make a working computer out of hoses and valves. There is a plumbing equivalent for every logic gate, and you may wish to look into [fluidics](http://en.wikipedia.org/wiki/Fluidics) There are plenty of steam fired power plants, nearly every nuclear or coal power plant for example. There would still be electricity. You note cars would still exist, there actually were [steam powered cars.](http://en.wikipedia.org/wiki/Steam_car) Aircraft would almost certainly be lighter than air, like zeppelins or blimps. The power to weight ratio on a steam engine is far too low. [Answer] As I understand the question, you are asking what would need to be removed from common knowledge in our world to create a steampunk world, right? The primary difference between steampunk worlds and our world boils down to something quite simple: oil. Obviously enough, if oil were not as cheep and plentiful as it has been in our world, the internal combustion engine will never take off because gasoline will remain prohibitively expensive. But the main difference between our world and a steampunk world isn't the internal combustion engine or computers. It's the plastics that are everywhere now. Without plastic as a building material, the traditional steampunk look of brass, wood, glass, and steel remain the primary building blocks. Electrical wiring has to remain thick and bulky without the plastic insulation that prevents shorts. Wood and brass are the default choice for light-weight building materials, simply because there are no lighter and cheaper plastics to replace them. And of course, plastic is completely dependent on oil. [Answer] You might be surprised but you don't need electronic components to have a computer. Mechanic is all you need: <https://worldbuilding.stackexchange.com/a/3724/147> Miniaturization is harder but it's still a computer. Prior to the combustion engine, most energy was produce with coal. Without this invention, most cars would have to use coal instead. Unless they are electric cars. Electricity can still be produce with coal and don't forget about the nuclear energy. They also produce power with steam. The main advantage of the combustion engine is it's efficiency. It's small enough to fit in a car. it's more complicated with a steam engine but one could speculate that it is possible to come up with something. [Answer] This is the subject of my favorite sci-fi series, the Everness trilogy, by Ian McDonald. I hope I can draw from there for inspiration on my first point (cars). * Cars: Sure, you could go for the classic steam-powered car, but I think electric would be more practical. As evandentremont and Vincent pointed out in their answers, steam power plants are still feasible generators of electricity. Electric cars are simpler than steam-powered ones, and, in this case, just as efficient. * Airplanes: I'll go along the same lines here. Electric propeller-powered aircraft could be ubiquitous. They're quite (like the cars) and efficient. * Computers: The idea of a steam-powered computer really made me laugh. Seriously, though, if we consider the steam-to-electricity route, underground illegal computers are always possible. > > What specific scientific discoveries (if any) would need to be skipped in order to have steam remain mainstream? > > > I'm thinking along the lines of power generation. Nuclear, solar, hydropower, geothermal, wind, etc. Basically, all forms of non-fossil-fuel power generation would have to be skipped over. It wouldn't be hard for nuclear, but solar and wind could be issues. Why solar? I'm thinking [concentrated solar power](https://en.wikipedia.org/wiki/Concentrated_solar_power). It would be obvious to a race using steam. [Answer] The other answers have covered some interesting points, especially regarding non-traditional computers. To cover a different angle: How would we get to a steam powered world? Had heating of water through nuclear means been discovered in the 1850s and as much scientific effort expended on that front as was spent on the novelty of electricity we would likely have miniturized Thorium nuclear steam generation before the first world war. Had this happened it is hard to say if the health effects would have been a public outcry given the generally accepted unhealthy practices of the time (ie we get more tumors than our parents generation but far les emphazema). As an additional angle to build to the steampunk world, nuclear generation of Hydrogen gas is cheap and efficient so gas to fill zepplins would be readily available. [Answer] Typically what led to the disappearance of steam engines is its replacement by internal explosion engines, which are the direct result of the discovery of large Oil fields, resulting in internal explosion engine being easier to implement and more efficient than steam engines. (Although the first Otto cycle was first built using coal gas, I don't think coal gas is a very convenient fuel. It was used at some point during WWII to replace petroleum, though.) Without oil, until electricity and nuclear I don't see what would have replaced steam engine. However, oil is typically produced by the same means coal is, so it is unlikely that a world with coal mines would not eventually strike oil. Early discovery of radioisotope thermic generator could explain the lack of further interest in other sources of power. [Answer] The biggest problem with steampunk is electronics - why would things be steam powered instead of electric? If electronics are developed, steam would be relegated to power generation just as it is in the real world. If no electronics, by what sense is this a 21st century civilization (rather the hallmark of a modern society)? If you include a greater knowledge and use of mechanical power transmission (good info [here](http://www.lowtechmagazine.com/2013/01/mechanical-transmission-of-power-stangenkunst.html)), steam certainly could be used for a great many more applications than we tend to use today. If you include cable or push-rod drives for direct transmission of mechanical power, we could have little steam engines practically anywhere. There are losses involved any time you change from mechanical (power plant turbines) into electric, and then back from electric to mechanical (your motor). Going directly from mechanical spinning of the steam engine to mechanical applications (transmitted by rope drives or push rods) is generally more efficient (and cheaper/easier to maintain and repair than electronics). Computers, as some have mentioned, do not really require electricity - that just makes them significantly faster. Computation can be done mechanically - there are [water integrators](http://en.wikipedia.org/wiki/Water_integrator) capable of differential equations, and the earlier punch-card computers were mechanically driven. Things just work so much faster on electricity rather than mechanical movements. Doing away with the internal combustion engine and reaching a mid-20th century level of civilization (just replace all IC engines with slightly less-efficient steam engines, though larger aircraft are going to have to be lighter than air) is very plausible, but something equivalent to current developed societies cannot happen without electronics (and once you have a decent understanding of electricity, steam goes away quickly). [Answer] I would scavenge on @evandentremont's answer a little and say: 1. Electricity does not conduct in wires, and 2. There are no liquids that give off explosive vapors. The 1st item means there will be no way to distribute electricity, at the very least. But you could have a 'pneumatic internet' etc. The 2nd item means there will be no IC engines, which really means no engines with a high horsepower-to-weight ratio. This world would be driven by steam. I would recommend that the reason that electricity and IC engines don't exist isn't because no one thought of building them, but because the physics does not work. Consider The Game of Thrones TV show. They have been stuck in a late medieval situation for a thousand years or more. Given we were in that phase for about 100 years, tops, it makes suspension of disbelief a little harder. I can't help but think, "What's wrong with them?" edit - the limitations above would not preclude modern machine guns. So you may need to tweak the physics a little more. [Answer] Easy way to get to steampunk world is to not allow for creation of huge amounts of fossil fuels in carboniferous period. Maybe planet started with less carbon overall. Less water. Maybe condition were not right and organics pertified as [kerogen](http://en.wikipedia.org/wiki/Kerogen) and not oil, and it is not effective to mine it for energy. No coal, no oil - no cars. So civilization started as powered by wood and peat bog heat, and upgraded to other sources of energy - hydro, wind, solar, and eventually nuclear. In such world, you can have transistor, computers etc. Small local transportation could be powered by compressed air. Everyone would have small home compressor, which would convert free night electricity (wind, hydro, nuclear work night and day) to compressed air, which will be converted to electricity during day, or power tools and cars. Not steam punk, but compressed air (and electricity) punk. Nice clean word. [Answer] As @Brian\_Drozd writes, it is important to have no plastics. But oil is not the only way to get it. It is possible to create plastic for example from orange peels. It is not so cheap and useful now, but with redirecting the effort invested in oil, who knows what other sources we would find. So I think it is impossible to give you an accurate answer - you change something, but people will find ways you couldn't imagine and it will end completely different from your idea, because you can't prevent things you don't know. It reminds me of one short story I read a long time ago. I do not remember who wrote it, but the plot is simple: It is somewhere in Arabia, I think around 1000 AD. A prince finds a beggar in his palace garden, sitting on edge of a fountain. Instead of driving him out, he feeds him. In exchange, the beggar reveals he is a genie and offers three wishes. The prince decides he want to see the future of the world, so the genie shows him how the world looks in few centuries. It is dominated by western civilization like today's, his own country is dry and poor and many parts of the vision touches a strange blue crystals. When the prince asks, the genie explains him that the crystals are mined in the western countries and they use it as a source of power. But in his country, there is just little of it. The prince doesn't like what he sees. After some thinking, he chooses his second and third wish: remove all the blue crystals from the world, and put something else here, into this land, so his descendants can mine it. "Granted," said the genie and he disappeared. A moment later, the fountain gurgled and smelly, thick black fluid began to pour out instead of water. [Answer] This is an old thread, but one that still comes up when you search for steampunk. So, for anyone reading this in 2020 or beyond... I think the only two realistic explanations for a 21st century in which steampunk level tech exists are: 1. A huge global disaster that drastically reduces the earth's population (along with much of the research and/or scientifically literate people) in the 1800s/early 1900s. I'm talking something on the scale of a severe global plague that mutates into a deadly and highly contagious form that absolutely decimates the human population worldwide. Or maybe a supermassive volcanic eruption (i.e. Yellowstone) that wrecks the atmosphere, causes tsunamis, global crop failures (and likely wars over food supplies), and leads to a mini ice age. The society that's left behind after conditions improve would essentially have to start over again with whatever scientific understanding the average layman had. 2. A very powerful, influential religion that infiltrates governments across the globe (or at least in places where scientific progress was being made in the 1800s). Something like the vatican mixed with a radical eco-warrior type movement that shuns certain technology and criminalises anything that goes beyond clear and obvious natural law (basically, a technology version of 'burn the witch'). People like Edison and Tesla are now hunted down and would-be investors are donating to the 'church' instead of backing research. Or maybe 1. results in 2. happening (since the crisis pushes many into the arms of religion for reassurance)? Which allows this religion to gain even more ground. Either way, you'd end up with social 'norms' stalling in the 1800s (when the disaster happens) but technological understanding massively reduced and having to play catch up once 'the dust settles'. So you could realistically enter the 21st century without events such as the industrial revolution, WW1/WW2, rights for women, etc (big social change) ever happening. And technology is whatever the average Joe can manage to work out based on what little they remember from school (if they even went). So likely not even to the level of steampunk in many areas. ]
[Question] [ For plot reasons I need a country that will always negotiate with foreign delegations using open door policy. The media can watch and record the negotiations but they can't participate. Is there a plausible way to explain this besides something like this is our custom or similar excuse? [Answer] # Internal politics. There was a period where the politicians made bigger and bigger messes and the voters grew more and more impatient with them. It seemed like everybody was corrupt. A new party called the Openness Party appears. They have a charismatic leader and win votes with a simple promise: "No more secrets!" It starts as a local party and wins the mayor's seat in a city. And they deliver. As the months go the city administration becomes more and more open. A number of corrupt city employees are discovered and punished. A major pollution problem is stopped when BigCorp can no longer bribe people to look the other way. The city budget improves as politicians can no longer attend "meetings" in faraway luxury resorts. The Parking Authority's private golf course is opened to the public. Riding a storm of public approval the Openness Party enters national politics and wins again. After a few years almost every aspect of the government is open to inspection by the media or by anybody who cares to do so. There are very few remaining secrets, all of them military in nature. When they meet foreign diplomats, of course they will invite media. Why not? [Answer] A plausible reason would be a Near Death Experience, for the country itself, such that secret negotiations and the corruption that naturally goes with it destroyed them economically and caused a major coup attempt that nearly turned them into a dictatorship. In the shooting war that followed to prevent this political disaster on top of an already devastating financial disaster that left them in a great depression, the government was reformed, as for the people. Part of that reformation was absolute public meetings, there are laws in place so if any politician meets with any other in private, both are guilty of a serious crime (mandatory sentencing of 3 years in prison, forfeiture of 100% of assets, and barred from politics for life). The people created a policing organization, the Congressional Collusion Investigation and Prosecuting Force (CCIPF), and they have draconian power to enforce it: Politicians cannot be friends with each other and make deals on the golf course, they will go to jail. The standard of proof is simply "preponderance of evidence"; the lowest bar (in the USA) for a conviction. Why would anybody become a politician? It pays very well, as much as, say, a surgeon. Plus half that amount for life after holding office; because they will also be prohibited for life from taking any other paid job or form of income, once elected. While holding office they get CCIPF bodyguards, they travel, they decide matters of national importance. They can have family and friends, they just have to be careful. But one of their official roles is campaigning, arguing for or against laws in the media, etc. Their CCIPF bodyguards are assigned and cycled at random; and also carry 24/7 recording equipment, the recordings are open to the public, and can be used in either prosecution or defense of any charges of collusion (e.g. accidentally shaking hands with another politician at a wedding is not collusion.) And CCIPF officers can wear GPS trackers when on the job, so they can all have electronic proximity alerts if any other CCIPF officers, assigned to any other politician, are anywhere near their charge. Communications could let them negotiate sufficient buffer space (or alertness) to keep them separated. The CCIPF will give them fair warning if anybody new in their life has political ties, or anybody already in their life develops new political ties. An honorable politician can make an upper class living for life, the job is relatively easy, and there will be no shortage of candidates. The CCIPF is similarly constrained: Investigations of politicians are publicly assigned to the CCIPF officers by lottery; and their own lives must be an open book, too. They can never, ever be politicians or involved in politics themselves; joining the CCIPF, even for six months, bars them for life from holding any elected or governmental office or even participating in a campaign or advocating for a particular politician, bill, or scheme. They cannot express an opinion between pro-choice or pro-life; they have no political free speech. They are allowed to vote, in secret, but revealing their vote is a crime. Every dime they earn or spend is recorded and public knowledge. Further, the CCIPF is funded independently by their own tax which politicians cannot touch, short of a complete rewrite of their Constitution. Further, the CCIPF itself is incapable of making any law or rule for the citizenry. It has its own court system with CCIPF judges, also assigned by lottery; and trials and evidence for collusion between politicians are public and the jury deliberations are open and recorded. Who enforces the laws against the CCIPF? The CCIPF; they are organized into a dozen independent bases in the country (like military bases). New recruits are assigned at random to one of these. Charges against CCIPF members are given a trial by CCIPF judges chosen at random from another base with a jury of their peers; one from each base. Other rules like that; like the USA military, the CCIPF is its own sub-culture, a semi-democracy with its own courts and rules about how to conduct itself. Make the country's wounds fresh, this all happened, say, 150 years ago, and people still honor the names of their relatives that fought and died to create the CCIPF. There are multiple national holidays celebrating various milestones in that "War On Corruption", statues to the heroes and first generals of the CCIPF, the first fallen in the name of Honest Government, and so on. That is the "social element", the CCIPF is seen like soldiers: Heroic, self-sacrificing, and utterly honorable; they are trusted because the structure leaves little reason to doubt them. Our soldiers protect us from foreign threats, the CCIPF protects us from being taken over by our own mentally ill citizens that have no conscience and seek only self-enrichment and megalomaniacal power, fame, and being feared. Even if politicians truly believe the open negotiation law is stupid and crippling, they do not violate it, they learn to work within these constraints because they have a good life if they stay within them, and there is too much to lose and not enough to gain by violating them. The uncontrollably greedy or megalomaniacs best not apply, they can exercise those traits in the corporate world. Politicians will be people happy with the generous salary, retirement, and other perks of being in the top management tier of the country. [Answer] Media Leaks. The country has a very large bureaucracy, with hundreds of individuals directly involved in negotiations, and thousands indirectly. It only takes one individual out of these hundred to leak a draft trade deal to the media, who will exaggerate and distort anything the public might find controversial. The leakers are motivated by money, politics, and don't fear releasing confidential information as they know they're very unlikely to be caught and prosecuted. After several high profile, secret negotiations being torpedoed by the court of public opinion, the country decides that action must be taken. However, it's not possible to reduce the number of individuals with access to this confidential information. Officials from various government departments require individual representatives, due to the complex nature of the talks. Additionally, there are many devolved regional governments, who all want a say in the negotiations. The information is going to leak, so why not control it on their terms, by televising all talks with foreign entities? The country can no longer be accused of making back room deals, and any aggressive tactics from foreign negotiators risk causing a diplomatic incident. Additionally the negotiating position of the country is now strengthened, as the public expects that red lines must not be crossed, and that the initially stated goals must be achieved. And of course, the whole thing is portrayed as a great victory for democracy and open government, rather than a cynical attempt at damage limitation. [Answer] One way to force this would be if (media) corporations had proportionally more power then they do here. If you try and rule the world it makes sense you want to at least know what's being said. Perhaps they lack to power to force a chair at the table. Maybe they don't wish to be so public about it. So the representatives are puppets and the journalists are those who make sure the right things are said. Now you might not want to do this to overtly so using the media broadcasts as cover isn't a terrible either. Alternatively you might want to force a narrative to your viewers. Show them the government is acting in their interest and not the filthy foreigners. Not trying to make a political point but imagine Fox News or Breitbart pulled into the extremes. They could create a narrative where the public is highly skeptical of an part of the government not actively endorsed in the media. As for how media corporations could gain so much power. Look at how elections are run these days. If you could control the narrative you can guide the voting public. Maybe the privacy laws aren't as good as ours. Maybe they got all they need to blackmail certain people in power. [Answer] In an age of ever-increasing social media and connection, a "true" Democracy might not even have a formal government. All decisions are reached by a vote; all "mature" (above some arbitrary age, or having some basic scholastic diploma) citizens can vote. Votes are done "in real time" for urgent issues, or within a "reasonable" timeframe (whatever that means) for less urgent issues. A diplomat would have to provide open negotiations observed by the media... because that's the only way the citizens could vote on whether or not to accept any treaties proposed. [Answer] Self-Preservation Imagine a Cold War type situation, two powerful rival nations at odds with each other, but not quite at the point of open fighting. Imagine a long, heavily fortified shared border between them - though at some point, that border is interrupted, with a much smaller, neutral, less powerful nation squeezed in between them. Our hypothetical smaller nation has favorable geography, perhaps easily fortified, mountainous terrain - such that if one of the larger nations were to occupy it, it would grant a significant strategic advantage. Luckily for our smaller nation, neither superpower is quite willing to attempt an invasion - they and their rival are evenly matched enough that any war fought over this nation would be costly, and it's outcome uncertain. And besides, being the first one to attack this neutral nation would drive them to align with the other superpower - in short, neither side is willing to invade to gain control of the smaller nation, because the status quo is preferable to the risk of their rival gaining that strategic advantage. That doesn't mean, of course, that the superpowers are happy with the status quo - both of them have, in the past, quietly sent envoys to try and convince the smaller nation to come over to their side willingly. If they did, however, it would surely leave the other superpower feeling as though they had no choice but to attack, rather than allow the balance of power to be upended. As such, the smaller nation has steadfastly remained neutral... but in several cases, rumors and misinterpreted intelligence have pushed things to the very brink of war. Every time one superpower's envoy makes a quiet visit, the other side masses more troops at the border. Not wanting to risk being overrun based on a misunderstanding, the smaller nation puts their foot down and declares that they will no longer conduct any diplomatic meetings in secret. Both superpowers are welcome to continue sending their diplomats, but in order to avoid any misunderstanding or misinformation, the meetings with them will be entirely public and open. [Answer] # Modern technology The country in question is a few decades more advanced than we are currently, such that ubiquitous minute insect-robots with recording devices, ultra-sensitive laser audio recording and nanotechnology make holding secret negotiations basically impossible. To avoid conflicting interpretations and recordings as well as public mistrust, and as part of a culture where citizens are already increasingly recording and broadcasting their everyday movements to the cloud (think Black Mirror), it is a natural progression to have all diplomatic and political negotiations made public. A decade later however, a scandalous case reveals a politician using their cyborg implants to conduct encrypted negoatiations wirelessly. How much of this diplomatic theatre was actually a sham? [Answer] I cannot think of a way, realistically, that a country would use open negotiations. The reason is that countries can have conflicting interests and compete over resources. ``` Country A uses open negotiations. Counties B and C are rivals with respect to a certain resource X. A needs something from B A needs something from C ``` Now if A helps B or C get X, the other will not take it kindly and may withhold what A needs. This is not good for A's citizenry. Further, if A chooses sides (say, chooses B), then it could mean war between B and C, and suck in A because of the needed resource that C possesses. The above is not hypothetical. That's what negotiations are about - avoiding a mess when people vie for scarce resources. So it would seem for open negotiations to work there must be no scarce resource involving a 3rd party. For example, in the example above, what if X were suddenly abundant. Now A could openly negotiate with B and C and not cause any strive at all. Another way would be for A to be a self-sufficient resource-abundant amoral super-power. Trading partners are unhappy? Who cares, we are self-sufficient. They're going to attack us to get a resource? Let them come, our might is unparalleled. Or we'll shower resources onto their barbaric rivals and let them do the dirty work in a very nasty and permanent way. What is often forgotten is what while an actor might be evolved and enlightened, other actors are not necessarily so. For example, would you treat France the same way you treat North Korea? I don't think so. So even the most enlightened country must take into account the barbaric nature of its neighbors. Regarding corruption... corruption does not happen at the negotiation table. It happens before the negotiation. Open Negotiations would not help. For example, many years ago, Japan was importing into the USA a certain car. The import tariff was applied in several stages, with the specific tariffs being dependent upon the type of vehicle. So Japan lobbied such that the vehicle would be reclassified depending upon the stage, in order to avoid paying as many import tariffs. For a small amount of money (paid to lobbyists, ostensibly), they netted a HUGE payback. If anyone needed to be bribed, it would have happened away from the table. ]

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