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Follow up to [my previous question](https://worldbuilding.stackexchange.com/questions/25415/on-the-habitability-of-the-night-side-of-a-tidally-locked-planet), after botched registration.
We have an Earth-like planet tidally locked to a star similar to Sirius A. The star does not belong to a binary system. The planet itself possesses an atmosphere, volcanic activity and large water bodies. As pointed out in [this Physics SE](https://physics.stackexchange.com/questions/29293/does-a-tidally-locked-planet-have-seasons), seasons would be the result of orbital eccentricity. A natural satellite orbits the planet.
The day side of the planet is inhospitable due to the heat from constant sunlight and most of it's water is likely underground. The twilight zone is also inhospitable due to strong winds created by the differences in temperature between the day and night sides. The night side is illuminated by the natural satellite, which has the same angular diameter as our Moon and an orbital period of about 30 hours.
Given that Sirius is 25.4 times more luminous than the Sun, would photosynthesis, and thus plant life, be viable in the night side of the planet? Would the plants need a different pigment, such as retinal rather than chlorophyl?
Thanks for JDługosz and Youstay Igo for their answers to the previous question.
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Photosynthesis is definitely possible. As the star is 25 times brighter (and hotter) than our sun, the moon would be really really bright and the "night" side of the planet would be in effect as bright as a winter sunlit day on earth. Photosynthesis is ON!
The only issue I have with such ghastly planet is the raging storms! In reality for such a planet, the vortexes and storms would not perpetually blow on the poles, but in fact ALL the planet's surface would be ravaged by horrible dunes and cyclones, the force of which makes me shudder in horror with the very thought of them. Just find some way of getting rid of these vortexes and the rest is all cool.
Oh yes. I recall. You will also need to get some form of ozone layer and a strong magnetic field. The magnetic field would keep the planet safe from the outrageously powerful magnetic storms on the star and the ozone layer would protect it from the devastating gamma rays, x-rays and ultraviolet radiation which would otherwise make life (on either side of the planet) impossible.
Large water bodies are good. The more water you have on your planet, the lesser would be the temperature difference. I would suggest a planet nearly twice the size of earth with 80% of it's surface covered with deep oceans. You will still get really large continents for your civilizations.
I think if you introduce really really lofty mountain ranges on the horizon boundary between day and night sides, you can effectively break the wind power to less than half. Higher in the atmosphere, storms would be RAGING but near the surface, breezes would be mild and pleasant.
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It's unlikely that a tidally-locked planet would have a moon to begin with. In our solar system, most moons form outside of the geosynchronous orbit. The few moons that do form within that orbit are doomed to eventually spiral inward and collide with the planet, as is the case with Phobos, for example. So for a moon to form a stable orbit around a planet, it has to have an orbit that gives it a longer revolution period than the planet's rotation period. In the case of a tidally-locked planet, that would be beyond the planet's Hill Radius. So yes, in theory, any planet can have a natural satellite. However, tidally-locked planets lack the ability to keep one.
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**How do you go about boosting an already-habitable planet's habitability?** I want to maximize biomass, hopefully cover the whole planet surface in luxuriant jungles and forests, brimming with insects, animals and (hopefully) megafauna, while the oceans are alive with kelp, invertebrates and fish of all shapes and sizes, all growing (if possible) at a greatly accelerated pace.
Optional extra info :
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> The Ssiws people want to make their (Earth-like) planet **super-habitable** (mostly for the purpose of roughing it out outdoors with the mega-beasts such an amped-up world will support, all in a potentially misguided attempt to feel more alive than in their ultra-safe orbital habitats). Incidentally, it's also good publicity for their main export IP product, the Ssiws Army Knife®. They have hired a famous eco-poetess, Deirdre Skye, and gave her essentially a carte-blanche on the planet, and the full might of their fabled zero-point drives to make it all happen reasonably fast.
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Note: To my mind, the obvious criterion for a good answer would be a listing of ***plausible actions*** (artificially sustained if need be, but keep it realistic) ***that would boost the total $biomass$ and $biodiversity$ to the max***. I'm open to being convinced of better criteria.
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Ok, to do this, you're going to need to do some major-league planetary redesign work. In order to get lots of life, you need lots of water. Deserts are the areas with the least diversity and biomass, so they have got to go. Where mountains are causing rain shadows, knock them down to size. Where rain is falling but the clouds are not being replenished fast enough to water the downwind areas enough, build intermediary seas. It would take quite a bit of digging, but you have that zero-point drive after all, and it shouldn't take too long.
Another step you'll need to take along the way is to increase the atmospheric carbon content a little, *without* causing an excessive greenhouse effect - the global temperature is just fine as it is, thank you very much. Again, it is fortunate that you have the Zero Point Drive, so that as you un-sequester all that geo-sequestered carbon, you can move the world further away from the sun so that the increased greenhouse effect is countered by reduced solar influx. Take it easy with this step, you don't want too much more carbon dioxide suffocating your animals, nor do you want to reduce solar influx too much.
As the plants that you're growing sequester the carbon you've been digging up, you'll need to gradually dig up some more carbon. That's right, get it all out of the ground and into nice, living plants. Keep the atmospheric CO2 within bounds though.
Another issue is Oxygen - you'll want more of it. Fortunately, as you're increasing the biomass of photosynthetic organisms, producing a bit more shouldn't be too hard, and you can help it along if you want. Increasing Oxygen from 20% to 30% or so would do wonders for producing megafauna. Make sure that you aerate the seas nicely too. With that extra oxygen, bushfires will be a bit more frequent, but that will serve to help the carbon cycle keep going without too much getting sequestered again. It will keep your animals on their toes or other locomotory appendages too.
Now you have water everywhere you need it, more oxygen and extra carbon going into plants and animals, the next step is biodiversity. Fortunately, you have Deirdre Skye, who the OP's previous questions have established as an expert genetic engineer. Having performed the first steps, you'll actually have set yourself up to *lose* some biodiversity, so just genetically engineer the desert organisms so that they can tolerate more water. Once that's done, start in on other species, and make a few variations of each. Mix and match traits and set the critters loose to fight it out amongst themselves to see who gets to survive. Inject enough genetic variation within a species, and you'll probably find the species splitting all by itself as the widely divergent members begin to evolve in different directions.
Megafauna are easy to achieve if you have an expert genetic engineer on hand, though they aren't *usually* the fastest-breeding critters - at least if they are mammals. How about a few species of Giant Land Crab instead, you know, engineered to weigh in at around the one-ton range and eat pretty much whatever they can get their claws on? They breed in water, so they can have thousands of larvae out at sea, growing on a diet of plankton to a size sufficient to climb out onto land and begin eating everything. You might have to change their oxygen carrier and their circulation, but that's just a little thing, really.
I don't know about accelerated growth, some life-forms grow pretty fast already, and biological process are only *so* fast, you know, you can't make them much faster without chucking the whole lot out and starting again from scratch, and I'm sure that you don't want to spend *that* amount of time repopulating your biosphere. The extra oxygen should pep things up a little, anyway.
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**Planet Size**
Larger planetary size for more land area. Keep density such that surface gravity is still 9.8 m/s^2. A larger planet provides more surface area to work with.
**Tectonics**
Very old world with little remaining tectonic activity, this shrinks the size of the mountain ranges through erosion and reduces land lost to rain shadows.
**Topography**
More land area but with lots of coastline. Eliminate broad intra-continent areas (cut down on deserts). The advanced age of the planet also means that erosion has had plenty of time wear down the mountain ranges into tall hills. This also means more slow river deltas and swamps to grow semi-aquatic megafauna.
**Atmosphere**
More oxygen, more CO2, less nitrogen. More oxygen means more fuel for life. Increased CO2 levels also increase the average surface temperatures. About 30C Let's keep atmospheric pressure the same as Earth.
**Air Temperature**
Higher surface temperatures. Higher CO2 concentrations achieve this. Life tends to grow more prolifically when it doesn't have to devote resources to staying warm.
**Rotation Speed**
Slower rotation for longer days and larger [Hadley cells](https://en.wikipedia.org/wiki/Hadley_cell).
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...where the Hadley cell descends and begins to move back towards the warmer areas.
**Moons**
Keep a single moon scaled to keep equivalent effects as earth gets from the moon. Having a moon sustains tides which have proved very useful for evolution and biodiversity.
**Results**
Because of the factors listed above, this planet should amply sustain a tremendous amount of life ranging from single-celled organisms all the way up to mega fauna in the form of giant snakes, crocodiles and probably dinosaurs (or dinosaur like). Every approach to life that exists in Earth's jungles would exist here too.
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In a thing I'm writing, the plot revolves around 'shards' fragments of a divine power that attach themselves to a rare few humans at birth- one in some many million. When that human hits a massive stress point, the shard and their body fuse together to transform them into a God/dess, able to discorporate at will. The new diety's purviews are the most important things in their life at that time- for example hurricane Katrina triggered the birth of both a storm goddess and a disease god. The gods have massive power in their field- that storm goddess could swamp north america for days, the disease god could wipe out europe in a few weeks.
Given that, my questions are:
* There is an equal spread between males and females who receive shards- how would that have impacted gender dynamics how and historically and what would medieval europeans have thought of war/destruction goddesses?
* How would Abrahamic religions explain this? What happens if a pope or priest ascends- especially if they become a god of sex or corruption etc.?
* Can you regulate beings of such power legally? What kind of laws would be needed to validate a new god's cult, or to stop divine wars?
Currently, about 200 gods exist, the 'old' gods- about 150 or so- only intervene at the behest of legally sanctioned high priests and otherwise just stay in 'heaven' or the underworld- humans get boring after a while and they find physical forms limiting. Younger ones tend to try and help the causes they supported in mortality. Human worship is equivalent to fancy foods- good to show off, makes them feel good- but not necessary. Pantheons are merely political alliances.
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This... is going to make a huge difference as long as it's actually fairly random. In our world 99% of medieval europeans were brutally oppressed constantly. So you have a 99% chance of a peasant god.
Currently there are 7 billion people alive. it's estimated that something like 100 billion of what could reasonably be called people have ever lived. If the 200 gods are culled from that number than only about 1 in 500 million people ever ascends. (if you want to boost that you might want to come up with some reason for the oldest ones to utterly lose interest in humanity)
Population of medieval europe was < 200 million so this is going to be a rare event.
So there's only going to be an ascension every couple of generations and odds are it's going to be someone who spent their life being treated like dirt by the local lord. Also they're likely to ascend at a moment of awful trauma...
If the ascended still care about the people and things they cared about before this does not end well for the aristocracy.
Every few generations an immortal god is likely to be born who likely wants to murder every lord, duke baron and king they can find.
So medieval history is likely going to look a lot different.
You talk of laws? What are laws that can't be enforced? Do the gods enforce some kind of law on each other? What leverage could any mortal have upon these gods? Remember that history doesn't look much different if you go back further, most of the older gods are also likely to be from the oppressed masses meaning the dominant force on this world is likely to be kinda in favour of treating serfs and peasants well.
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This makes for an *interesting* alternative reality.
Q: There is an equal spread between males and females who receive shards- how would that have impacted gender dynamics now and historically and what would medieval Europeans have thought of war/destruction goddesses?
A: Imagine Joan of Arc becoming Goddess of Fire...and burning down a cathedral. That I think would have further escalated the already very skewed gender relations. Women would have been oppressed even more. And possibly escaped into underground female goddess worship along the lines of witchcraft. Joan would be a very controversial figure but NOT in her face.
Q: How would Abrahamic religions explain this?
A: Obviously the devil tempting the faithful. It is all a test, ignore! Makes room both for real pure faith AND bigotry.
Q: What happens if a pope or priest ascends- especially if they become a god of sex or corruption etc.?
A: Fun! Huge scandal and see previous answer.
Q: Can you regulate beings of such power legally?
A: Humans cannot, so self-regulation it is. Job for the eldest/most powerful god(dess)? No matter it will be a messy situation.
Q: What kind of laws would be needed to validate a new god's cult, or to stop divine wars?
A: New religions have a history of conflict with the powers that be. So any law would be a paper tiger and any number of applicants would be faking it. Stopping a war of any kind is even harder. So what I see is chaos. And a God channel on TV.
Are gods able to grant wishes, convey powers on the worthy?
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I know living on Venus would be virtually impossible for us now. But I'm trying to picture what life would be like on the surface of such a world, and how advanced in technology a species would have to be in order to achieve it.
Whatever species is on Venus obviously didn't originate there, so this Venus like planet would be a colony of sorts. I am placing no limits at this point on how advanced this species could be, but they are either humans or humanoids.
If I wanted to build a base on the surface of a planet like Venus, with its thick, crushingly heavy corrosive atmosphere, intense heat and rivers of lava, what kind of technologies would I need?
I'm thinking the Venusian Base would be something like a large pressurized container with its own internal environment, that was strong enough to withstand the atmosphere. But I wonder if this is enough? How would people get in and out of the base? Would mining activities be possible from within the base?
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Just building a base might even be possible with current technology, just incredibly expensive and very challenging from an engineering perspective.
Dealing with the pressure is in princple no different than for a submarine. It just requires a strong pressure hull. The surface temperature can be dealt with, 450°C isn't hospitable, but at least its not so hot that everything melts, so a base could be constructed using more or less common materials. Isolating the base is in principle no different than isolating a fridge to reduce heat transfer from the environment; just the scale is a little different. Its all technology we already posess, whats missing is just the engineering work to put it together. And a way to bring it to Venus XD.
Living on such a base would in many respects be similar to living in a submarine. Access to the outside is impossible, or at least if a pressure suit can be made it will be pretty cumbersome and heavy. More likely surface activities, if at all, would be restricted to using some kind of vehicle, probably resembling something in between a tank and a submarine. Deploying and retrieving the vehicle could work the same way as with an airlock, just that the high pressure is on the outside.
If any mining is done, it would most likely be all robotic. But considering that about anything you could possibly mine from Venus could be obtained much easier elsewhere, mining seems mostly pointless. A base could more believably be scientific, and mining be replaced by drilling to learn about geology... erm whatever the term for studying Venus rocks is.
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There used to be a lot more science fiction about colonizing venus. That was until we actually sent probes there, took one look and decided, "You know what? Mars is actually pretty nice."
**The Surface**
The surface is difficult. I imagine it would be a similar habitat that could survive under a kilometer of ocean inside a volcano. Very high pressure and very high temperature. We don't currently have any habitats that can even survive the pressure, 9.2 MPa. That's 90 times Earth atmosphere. The temperature is hot enough to melt lead, 462 °C. We would have to expend a lot of energy just to keep cool.
We'd have to bring everything for life. There is no water or molecular oxygen (though we might be able to scrub oxygen from the atmospheric $CO\_2$).
One relatively neat thing for a base there is the Sun will set in the East. Venus rotates in the opposite direction on its axis than Earth. It wouldn't be totally obvious, since we achieve the same effect on Earth by confusing north and south. However, as boring as that is, it might be the neatest thing about living on the surface.
**Alternative**
It's far more likely we'd have [floating habitats](https://en.wikipedia.org/wiki/Colonization_of_Venus#Aerostat_habitats_and_floating_cities). It's certainly much nicer up there, where the planet isn't trying to kill you.
The atmosphere is dense enough that our normal breathing air could be stored in a massive bag and used as a lifting gas. A blimp that stores our breathing air is pretty cool. Once the floating habitat was set up we might make excursions to the surface. This method makes a lot of sense, it's what we do with the ocean.
So, exploring and colonizing Venus will almost certainly be from 50km up. Miners, or more likely miner robots, will make dives to the surface. But unless we terraform, humans or other fragile human like creatures, won't be living on the surface.
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Personally I'd start exporting bacteria or similar to Venus right now who thrive on heat and pressure, and who consume carbon dioxide and methane and excrete solid carbon in a useful form. The more carbon we can strip out of the Venusian atmosphere, and sequester in its surface, the faster it will cool down. Frankly we could use such bacteria here on earth, so long as we were assured that they wouldn't mutate into something that wiped us or our life-supporting ecosystem out.
In that regard, Venus is a great lab for such experiments. It might take ages to cool it down to habitable levels - can someone run some numbers? - but it would be handy to have a backup planet in the same neighbourhood if it is at all possible. And even if we don't manage to get a habitable planet out of it, maybe we'll get some useful science from it.
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How probable is it that a gas giant planet made of "air" (roughly the same composition as Earth's atmosphere) could exist?
What would it be like? How would it differ from Earth?
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There are two parts to this question:
1. Could a massive planet amass large quantities of nitrogen and oxygen?
2. Could these gases be the main ones the planet is composed of?
Giant planets relatively close to the central star (but beyond the [frost line](https://en.wikipedia.org/wiki/Frost_line_(astrophysics))) will accrete large quantities of hydrogen and helium, which were the major components of the initial gas and dust that surrounded the Sun when it first formed. These planets are massive enough that it is simple for them to retain their atmospheres of these light gases.
However, less massive planets (such as the terrestrial planets) will lose any initial hydrogen and helium envelopes via [atmospheric escape](https://en.wikipedia.org/wiki/Atmospheric_escape). The only planets that can possibly retain these gases are the most massive giant planets, which then amass enormous atmospheres. On these planets, there is no possibility of having an Earth-like atmosphere.
Planets further out can have interesting compositions.1 If you move far enough away from the central star, [ice giants](https://en.wikipedia.org/wiki/Ice_giant) can forms. Uranus and Neptune are examples (they are not, technically, gas giants). These giant planets are composed of heavier elements than hydrogen and helium - ices, which may include oxygen, methane, sulfur and nitrogen. They also, however, have hydrogen and helium, which, though composing much of their volume, only contribute about 1/5 of their total mass.
Ice giants are better targets for the kind of atmosphere you want. The issue, though, is that the oxygen and nitrogen you want may be in solid form, and even if some of it is gaseous, there's still a large atmosphere of hydrogen and helium to deal with.
The good thing is that exoplanets are not just either terrestrial planets or gas/ice giants. There are several intermediate classes that could help you:
* **[Super-Earth](https://en.wikipedia.org/wiki/Super-Earth):** A massive terrestrial planet that could have an atmosphere of hydrogen and helium or other key [volatiles](https://en.wikipedia.org/wiki/Volatiles) (including ices).
* **[Gas dwarf](https://en.wikipedia.org/wiki/Giant_planet#Gas_dwarf):** A low-mass gas giant with a less-massive core and atmosphere.
* **[Mini-Neptune](https://en.wikipedia.org/wiki/Mini-Neptune):** A type of gas dwarf, possibly composed of ices.
* **[Massive solid planets](https://en.wikipedia.org/wiki/Exoplanet#Massive_solid_planets):** Planets that have a rocky core that constitutes a significant fraction of their mass (which can range from Earth's mass to a gas giant's mass) while retaining an atmosphere of hydrogen and helium.
All of those planets sound similar, if not the same. That's because not much is known about them, and their characteristics are largely hypothetical, though some candidates have been observed. Tweak some things and maybe, just maybe, you can figure out a way for one of them to have "air."
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1 Although they may have formed further in and [migrated](https://en.wikipedia.org/wiki/Planetary_migration) outwards.
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My entry for the fortnightly topic challenge:
You are a space explorer. You are visiting this weird habitable planet in the Alpha Centauri System as part if the first manned expedition to another world. You see weird things floating in the upper atmosphere/space but think nothing of it, despite how much they look like living things. On a trip to the surface you see a similar shaped animal. At first you think it is a coincidence, but while exploring, you see one on a ledge on a tall cliff. It runs, jumps and takes off, using ocean thermals to rise, then flapping its wings as it got higher. Eventually it was out of sight. You had your space station base scan for it and found it was rapidly approaching the upper atmosphere.
**We have talked about how a plant could do inter-planetary travel via seeds. Is there any way for my creature to reach the upper stratosphere, near the mesosphere? Is there any evolutionary advantage that could be gained that would spark this creature into existence? How would the creature re-enter the planet without burning up?**
**CRITERIA THE CREATURE MUST MEET**
* must have wings
* must at least reach the very top of the troposphere, preferably the stratosphere, though.
[](https://i.stack.imgur.com/fpuld.jpg)
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In a word: **absolutely**.
Already, there are species of birds, like [Rüppell's griffon vulture](http://en.wikipedia.org/wiki/R%C3%BCppell%27s_vulture), that fly into the the stratosphere. It would be quite easy for a winged creature to evolve that floats or glides at an even higher altitude. I imagine that there are a few paths that could result in such a creature.
First, I could envision sexual selection as a driver the pushes the species into the upper atmosphere: the male that flies the highest gets the females kind of thing.
However, there's a limit to what wings do for you. Once you get above a certain altitude, the air density gets too low, and a winged creature would be unable to control themselves, or provide lift. Larger and larger wingspans could accommodate this deficiency, and that would lead more to lazy gliding/floating in the upper atmosphere, rather than high-speed flying.
Second, there could be a predator/prey relationship, which caused two species to evolve in an arms race, where high-altitude was the evolved escape path. In this scenario, a bird-like species would have to be an apex predator, which means that other bird-like creatures are at risk. Perhaps, a species has evolved a way to fly above the apex predator, which, due to the predators' weight, would be unable to fly as high.
This relationship already exists with the [Common Crane](http://en.wikipedia.org/wiki/Common_crane) and their eagle predators. If the eagle were a more effective predator, or they had fewer prey options, going even higher would continue to be a viable survival strategy for the crane.
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To cover our bases, let's talk about air density and survivability at upper altitudes.
As we go up in altitude, the air pressure rapidly decreases. This makes breathing, flapping, and gliding harder. The first one could be handled by holding your breath, or specially adapted lungs (the combination is what we see in high-altitude birds today). The second two can be corrected by lower body mass and larger wingspans. That combination can be challenging, because you need more muscle to pump larger wings, but we already see birds that are balancing those two elements to fly to astonishing altitudes.
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So by flapping it isn't going to be able to reach the altitudes you are wanting at all.
Basically your creature is probably somewhat naturally lighter than air with a very large wingspan. Your creature has the ability to rapidly fold up its wing span, fill up and compress large volumes of gas, which it then expels at high velocity. The creature would also have to be highly heat resistant, especially where it has created the rocket/ram jet. It would probably have to be photosynthetic and also a carnivore; how such a creature would evolve and what advantage it would have by being mildly explosive with a heat resistant shell but also basically a flame jet (regardless of there necessarily actually being a flame) is not something that I am willing to speculate on.
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If the creature does not have to go into orbit then it can build up speed before pitching up and trading speed for altitude. It will only be able to stay their for a moment before gravity will take over and it will come back to earth.
The main issue with reentry is speed. If you are only suborbital you won't have as much speed. I think a good model to look at would be the Virgin Galactic ships Spaceship 1 and Spaceship 2.
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I'm working on a random world generator, and want to generate names for the various tribes that inhabit the world.
On Earth, while different tribes and civilizations have different names, they tend to share common patterns of sounds that add regional cohesion to an area. I could randomly generate all of the names with vowel/consonant strings, but I'd like the names to have some coherence based on common language families.
On Earth, most of these differences are based on regional variations of languages utilizing different phonemes, having different words for things, and having different ways of combining words, combined with some drift in how specific words are then pronounced. If I don't want to delve into developing a linguistic history for each tribe, but I know where they came from, what tribes the split off of, and who else is nearby, how can I go about giving them all names that yield the same sort of linguistic cohesion that's found in the names of cultures on earth?
NOTE: I'm using culture/civilization/tribe fairly interchangeably, because for now, tribes are the only defined group I have. Eventually I'll have larger geopolitical groups, but I'm starting small.
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It is difficult to show linguistic/cultural differences in just a single name, because the factors influencing names can be highly random or complicated. For example, California is thought to be based off a fictional place name, not the English, Spanish, or Native American roots that might be expected.
That said, to generate convincing words for different languages in general, you should focus on how to implement an algorithm that takes into account the differences between languages. To list some of these:
1. Sounds available. Vowels, consonants, and other sounds. For example, Welsh has the unusual *ll* sound, which I am not aware of any other language, even related languages, having. Or, in syllabic languages like Japanese, the syllables available.
2. Syllable frequency. While letter frequency is often looked at, syllable frequency is more useful when considering the differences in languages. Even different dialects of the same language (British vs. American English) can show shifts in the actual syllables used. For example, *o* vs. *ou* in American/British for words like honor/honour.
3. Name length. While word length varies wildly within languages, name length can be more constant within a language, and considering that's what you are looking at, it is worth thinking about. Difference in name length could indicate change in dialects over time.
4. Syllable combinations. A lot of syllables tend to occur more commonly beside each other. This however would be difficult to model in the way I am about to suggest, unless you use a syllabic language.
However, all these factors are interconnected. Languages with more sounds and more varied syllables will result in shorter word length. Languages with syllable structures will tend towards long words, although some develop ways to shorten combinations of words similar to acronyms.
There is actually a rather solid theory within anthropology that states that linguistic change occurs at a fairly predictable rate, no matter the context. I would further recommend reading papers by Morris Swadesh on this topic.
My suggestion on actually technically implementing this is as follows. Define a set "drift" costs/probabilities for each element of language. Shifting syllable frequency might cost 2, creating a new common syllable might cost 10, and creating a new sound might cost 50. The closer to (or more in excess of) these costs, the more likely they occur. You might want to keep separate counters for each element, and reduce those by the "cost" each time one happens, to avoid unusual behavior.
These costs could be reduced if one of the other tribes has developed similar to reflect linguistic spread. Removal of language elements should also occur, and be impacted similarly by the presence of other tribes. However, elements of language are more commonly added or changed than outright removed.
From this, essentially run a simulation over some number of years, giving some amount of drift points per year (given the numbers I suggested above, it would likely be around 0.25). Increasing this value would increase drift between the groups, and could be used to indicate periods of cultural upheaval if necessary.
From that, you should basically have a list of syllable probabilities, and it would be trivial to generate a *Lorem Ipsum* style output for that, which of course can be used to generate a single word for a name.
This might be more complicated than what you want, but elements could be cut out to simplify it. Further, I think this would not be as technically complicated to implement as it is to properly describe. The most complicated necessary part, the generation of words from a list of syllable probabilities, would be included in any approach.
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if your world's political groupings are developed to the tribal level (and not more so than that) there's a few things that should be borne in mind:
1. often the strongest tribe or tribal confederation will determine the widely accepted names of other tribes.
1.1 often the names powerful tribes assign to lesser tribes are toponymic. so once you've decided the most powerful tribe in your world, or a region of your world, those around them may have names related to rivers, hills, forests and other environmental features.
1.2 the determination of tribal affiliation will often turn on if enough people in the powerful tribe vouch for you, and/or the accent you have when you speak.
2. what the members of a tribe call themselves is trickier. it may be a form of their language's word for 'people' or 'social group' (on the notion that those from outside the tribe are not *really people*), or it may describe some cultural or physical trait (perhaps lost to history) that the people consider indicative of their tribal membership. an example is 'lombardy', who popular etymology says came from 'longobards' or 'long beards', a reference to their dress when marching to combat.
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In my universe, there are sixteen living species from the *Homo* genus: anatomically modern humans, therianthropes, vampires, wizards, trolls, orcs, goblins, gnomes, ogres, dwarves, giants, halflings, elves, merfolk, angels, and demons.
In some species, both males and females (and by extension, intersexes) have facial hair. This is the case for dwarves, for therianthropes, for goblins, for halflings, for wizards, for gnomes, and for demons.
In some species, both females and males (and by extension, intersexes) lack facial hair. This is the case for elves, for vampires, for ogres, for giants, for merfolk, and for angels.
In all other species, most individuals with facial hair are males. This is the case for anatomically modern humans, orcs, and trolls.
So, I wonder why would adults of either sex normally have facial hair in some species, and at the opposite, why for others, most adults do not have facial hair.
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# The Non/indirectly-gendered Uses of facial Hair:
According to [some experts](https://www.wired.com/story/facial-hair-is-biologically-useless-so-why-do-humans-have-it/), facial hair serves only ornamental functions. There may be some roles in male-to-male roles and dominance, sexual signals, and signaling age, but the general consensus is that the function isn't a functional one but a psychological one. So what can we come up with in this case that makes the facial hair make sense?
1. **Speciation**: All your species and sub-species may be able to interbreed, but this isn't always a good thing. If a species has facial hair on women, those women may appear more masculine to other species. The facial hair may be a signal within the species that this is "one of us," while making the females of the species less desirable to members of other species.
2. **Patriarchal/Matriarchal culture signaling**: in interacting with other species, there may be social advantages conferred if the females look male to other species. A paternalistic species may give more status and respect to a female if they subconsciously equate them with males. Conversely, a maternalistic or egalitarian species with facial hair might still get along better with males of another species with facial hair, subconsciously supporting another species gender roles.
3. **Status/rank**: since facial hair tends to develop with age, facial hair can signal an individual's rank in society. The hairless young have little status, but males and females alike with facial hair are respected. This also means those who are shaved are effectively demoted in society, so forcing others to shave could be used as a means of control, and species with NO facial hair might be looked down upon (especially relevant if there is an 'inferior' species dominated by another which lacks facial hair).
4. **Environment-specific**: Perhaps in one region, the local species has extensive facial hair, which helps prevent frostbite. Or a given species has a sort of 'hair filter' that screens out a certain kind of insect or particulate in the environment. Maybe the hair has become like a modified scale that protects the face from injury during feeding, or perhaps one of your species uses facial hair like a cat's whiskers to convey sensory information.
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For the species that have facial hair on both sexes, there are several options to explain them. First females of the species Homo Sapiens do in fact have facial hair in certain situations (<https://en.wikipedia.org/wiki/Hypertrichosis> ) in fact a lot have relatively minor facial hair that are not caused by genetic mutations. Therefore it could simply be explained as weird genetic mutations. However about evoluionary developement, as beards were most likely evolved as a way for humans to help identify other humans, thus I cannot see why this cannot be applied for both sexes.
About the species without facial hair, it could again simply be explained as random mutations, as there ar already human populations which notably lack significant facial hair.
P.S. Sorry if this is a bad answer, I am new.
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**I'm designing fauna for my story and I'd like to incorporate birds but with a twist! Instead of having wings adapted for flight their legs serve that purpose.** Ordinary birds have most their muscle mass dedicated to flight which is good but leaves them very literally chicken legged. Flightless birds on the other hand have their muscle mass reallocated to their legs but as a result their wings become vestigial. So the idea is that a bird with wing-like legs would have all of its primary muscle mass useful for running and flying. Two birds with one stone (excuse the puns). This is similar to the [quetzalcoatlus](https://fi.wikipedia.org/wiki/Quetzalcoatlus) which is theorised to push off the ground with its wings to take off. Also similar to the [sharovipteryx](https://en.wikipedia.org/wiki/Sharovipteryx) a lizard that glides with its hind legs.
The bird is somewhat ostrich-shaped with two strong legs with a special toe which houses the [alula](https://en.wikipedia.org/wiki/Alula). This third toe is bent upward while walking so that the feathers don't drag on the ground. It's wings are either repurposed to be talons like those of eagles to catch prey while in flight, or simply reduced to vestigial limbs to make their figure more aerodynamic.
This sounds great but as always with biomechanics it's quite complicated to pull off. The entire pelvic area will be significantly different to allow powered flight, I have trouble imagining how it would work. There's also the fact that muscles for flight would be different from those for walking. Lastly a possible balance problem while in flight, how might the birds position themselves to pull this off?
Why do this? Because leg day is important.
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**Butterfly kick.**
[](https://i.stack.imgur.com/xbqcG.jpg)
<https://www.swim-teach.com/butterfly-kick.html>
Let us consider aquatic propulsion. Cetaceans and manatees have a long tail which propels them by moving up and down in the vertical plane. Humans can simulate this propulsion by holding the legs together and moving in a vertical plane similar to a dolphin tail.
Birds like cetaceans and humans are descended from land animals and like them have a spine adapted for land. An avian spine will flex vertically.
You have mandated that the bird has legs for land use. I propose that in the air it will flex and extend these legs (and associated wings) in a manner like a butterfly kick or a dolphin tail. The legs will splay in a letter Y with the large single wing between. The tail will also be used to steer and for balance.
On the ground this creature will not run like an ostrich because the wing extends between the legs. It will hop, mightily. Birds have a long track record of successfully getting around by hopping. The mighty hop will also get the bird clear of the ground so it can spread its wing and continue on.
The bird can also travel on all 4 limbs when slower or more measured movement is needed. The forelimbs are not needed for flight. They are grasping limbs like the foot of a parrot and used for arboreal movement. The forelimbs are also used to grab prey out of the air or off the ground in the way hawks and owls use their feet. The bird can hold prey and dispatch it with its beak, and then eat while in flight.
[](https://i.stack.imgur.com/gHeKh.jpg)
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I imagine it will look something on this line, with the flat of their feet retracted at tips of the wings.
Or with the tights acting as the flying surface and the (long and thin) calves bent back towards the body, the knees being the tips of the wing.
[](https://i.stack.imgur.com/cxquU.png)
Note that a [Forward swept wing](https://en.wikipedia.org/wiki/Forward-swept_wing) is unstable under stall conditions, and such a flight regime it's a very energy consuming one, albeit quite maneuverable.
Not likely to like perches and branches as a landing spot, the mix of "landing gear and wing" makes it difficult. Maybe plains or mountains with ledges as a habitat.
Same args would lead against a seed-based diet. With a little bit of care, one may think of water birds, a supple torso, long neck and beak may be adapted on the frame without damaging the aerodynamics.
If the flight is used for hunting, it relies on speed and maneuverability, **short flights** (no soaring like an eagle), plenty of food around. Either:
* small sized insectivore birds (and one can think of colonies of them); *or*
* large birds (still in an areal with plenty of food) but solitary - otherwise they'll deplete the prey around quite quick
One think I'm sure about: I'd hate to be an egg in a belly with such strong muscles that are used for flight and as a shield against accidental impacts on landing.
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## Probably like the drawing of Microraptors below
(as taken from the Guardian)
[](https://i.stack.imgur.com/NCbYu.png)
There have been lots of fossil finds the past few years and quite a few species identified.
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In an aquatic environment that most predators developed shark-like electroreceptive organs, what would be the counteractive measures against it?
[Copper shells](https://www.futurity.org/camouflage-shell-1182802-2/) can disguise electric fields, but how it would evolve naturally? Biometal scales? Late-stage bamboo shark embryos [cease all respiratory gill movements](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3541397/) when exposed to predator-simulating electric fields, but there are no records of prey animals modulating their own bioelectrical signals to reduce predation risk. Therefore, a coherent *electric stealth mode* would be viable for living beings?
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Aquatic animals display a variety of modes and uses for electroreception. For best results, you're going to want an environment where electroreception is their primary means of both locating *and identifying* prey - as opposed to identifying targets by sight, then using electric signals at close range if the target is hiding. This would most likely be in extremely turbid waters where there is little available light.
Animals that use [active electroreception](https://en.wikipedia.org/wiki/Electroreception#Active_electrolocation) - generating a low-level electrical field and measuring distortions in the field, similar to echolocation or active sonar - have a high degree of control over the frequency and modulation of the field. They can sense other animals using electroreception on similar frequencies and [shift to avoid jamming each other](https://en.wikipedia.org/wiki/Jamming_avoidance_response), and some species use it for [active communication](https://en.wikipedia.org/wiki/Electrocommunication).
With these sophisticated uses of electricity, it seems plausible that, in an environment with a lot of different species using active electroreception, prey species and smaller predators sense attackers' electric fields and respond with [deimatic behaviors](https://en.wikipedia.org/wiki/Deimatic_behaviour): startling and warning displays. This is similar to the patterning employed by butterflies, variously signaling (or bluffing) about their poisons or trying to mimic different predatory animals. Because these displays are about *adding* to a creature's electric field rather than removing it, they can use the same type of electrogenerating organs as other existing behaviors such as communication.
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Our solar system has 4 gas giants(Uranus and Neptune are technically ice giants, but who cares), which share nearly 200 moons amongst them. Yet all of these moons, even the giant ones like Ganymede, are not like their parent planet in any way. They have no hydrogen or helium, while Jupiter and Saturn are 90% hydrogen. But is it possible for a massive moon to maintain a hydrogen layer? The moon would have to be at least 2 times the mass of Earth to maintain the hydrogen layer. This would mean the giant planet would EITHER:
A: Be a brown dwarf, which could mean habitable moons, OR
B: Have to capture an already existing planet. B seems the most likely, but where would they have to orbit to avoid getting their atmospheres stripped away by the giant's gravity? Could these moons be massive enough to have moons of their own? What would be the composition of such a moon? How would the giant planet be affected? And are these moons even possible?
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This page lays out why planets and moons have the atmospheres that they do.
[http://abyss.uoregon.edu/~js/ast121/lectures/lec14.html](http://abyss.uoregon.edu/%7Ejs/ast121/lectures/lec14.html)
[](https://i.stack.imgur.com/nbYIH.gif)
>
> Combining the variables of escape velocity (mass, radius of planet)
> and surface temperature (distance from Sun plus effects of atmosphere
> heating) produces the following diagram. For key elements, lines are
> draw to show where the element escapes from the planet. If a planet is
> below that line, that element will escape.
>
>
>
All planets start with all gases. Bigger planet = higher escape velocity so they keep more gases. Smaller gas molecule = higher velocity and these molecules escape easier. Hotter = higher velocity and hot molecules escape easier.
Earth and Venus are close to the same size (and so same escape velocity) but because Venus is hotter, water molecules moved fast enough to escape Venus and Venus lost its water. Triton is a lot smaller than Earth but also a lot colder so the cold water molecules could not escape. Triton kept its water.
The thing about hydrogen and helium is that they move so fast that you have to be massive to hang on to them. Or extremely cold. An Earth mass planet the temperature of Triton would be above the lines for hydrogen and helium and so would keep both.
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The smallest known moons in the solar system are very tiny compared to their planets.
For example, A moon one kilometer in diameter could orbit a gas giant whose rocky core - not counting the thick layers of atmospehre - is 10,000 kilometers in diameter and thus has a volume and mass 1,000,000,000,000 times as great as the moon.
In fact, if this list is sorted by radius, seven moons of Jupiter have radii of about 0.5 kilometer and thus diameters of about 1 kilometer, and two moons of Saturn have radii of about 0.15 and 0.33 kilometer and thus diameters of about 0.30 and 0.66 kilometer.
[https://en.wikipedia.org/wiki/List\_of\_natural\_satellites[1]](https://en.wikipedia.org/wiki/List_of_natural_satellites%5B1%5D)
At the present time there are 202 known satellites of the four giant planets.
Some of them should have less than a trillionth of the mass of the rocky cores of the planets they orbit, let alone the total mass of their planets.
Jupiter has a mass of 318 Earth, Saturn has a mass of 95 Earths, Uranus has a mass of 14.5 Earths, and Neptune has a mass of 17 Earths. The approximate lower mass limit for a brown dwarf is about 13 times the mass of Jupiter and thus about 4,134 times the mass of Earth. But that is a very rough approximation.
Ganymede, most massive moon of Jupiter, has a mass of 0.0248 Earth, 0.0000779 that of Jupiter; Titan, most massive moon of Saturn, has a mass of 0.0225 Earth, 0.0002368 that of Saturn; Titania, most massive moon of Uranus, has a mass of 0.00059 Earth, 0.0000406 that of Uranus; and Triton, most massive moon of Neptune, has a mass of 0.003599 Earth, 0.0002177 that of Neptune.
Planetary astronomers divide terrestrial planets from gas planets by radius and not by mass, so a planet of the same mass could be either a terrestrial planet or a gas planet depending on how much athmospehre it has.
>
> A gas dwarf is a gas planet with a rocky core that has accumulated a thick envelope of hydrogen, helium, and other volatiles, having as result a total radius between 1.7 and 3.9 Earth radii (1.7–3.9 R⊕). The term is used in a three-tier, metallicity-based classification regime for short-period exoplanets, which also includes the rocky, terrestrial-like planets with less than 1.7 R⊕ and planets greater than 3.9 R⊕, namely ice giants and gas giants.[2](https://en.wikipedia.org/wiki/Mini-Neptune)
>
>
> Theoretical studies of such planets are loosely based on knowledge about Uranus and Neptune. Without a thick atmosphere, it would be classified as an ocean planet instead.[3](https://en.wikipedia.org/wiki/Exomoon#List) An estimated dividing line between a rocky planet and a gaseous planet is around 1.6-2.0 Earth radii.[4][5] Planets with larger radii and measured masses are mostly low-density and require an extended atmosphere to simultaneously explain their masses and radii, and observations are showing that planets larger than approximately 1.6 Earth-radius (and more massive than approximately 6 Earth-masses) contain significant amounts of volatiles or H–He gas, likely acquired during formation.[6](https://en.wikipedia.org/wiki/List_of_natural_satellites) Such planets appear to have a diversity of compositions that is not well-explained by a single mass–radius relation as that found for denser, rocky planets.[7][8][9] Similar results are confirmed by other studies.[10][11][12] As for mass, the lower limit can vary widely for different planets depending on their compositions; the dividing mass can vary from as low as one to as high as 20 M⊕.
>
>
>
[https://en.wikipedia.org/wiki/Mini-Neptune[2]](https://en.wikipedia.org/wiki/Mini-Neptune%5B2%5D)
It seems that the least massive gas dwarf planets might possibly have masses similar to that of Earth.
So if a gaseous moon the mass of a gas dwarf planet would suffice, it is possible that a moon only as massive as Earth might possibly sometimes be gaseous.
If the limit between a gas giant planet and a brown dwarf is about 13 jupiter masses or about 4,134 Earth masses, if a gas planet at the edge with about 4,134 Earth masses had most massive moon with the Uranus-Titania mass ratio that moon would have a mass 0.167 Earth mass.
If a gas planet with a mass of 4,134 Earth masses has a largest moon with the Jupiter-Ganymede mass ratio, that moon would would have a mass of 0.322 Earth mass.
If a gas planet with a mass of 4,134 Earth masses has a largest moon with the Neptune-Triton mass ratio, that moon would would have a mass of 0.8999 Earth mass.
If a gas planet with a mass of 4,134 Earth masses has a largest moon with the Saturn-Titan mass ratio, that would would have a mass of 0.978 Earth mass.
So going by the examples in our solar system, it should be possible for a few of the very most massive giant planets on the border with brown dwarfs to have moons as massive as the planet Earth, and it is possible that objects no more massive than Earth sometimes becone gas dwarfs.
But consider the example of the Earth and the Moon. The moon has mass of 0.0123 Earth mass. If a giant planet on the border with brown dwarfs with a mass of 4,134 Earths had a moon with that mass ratio that moon would have a mass of 50.848 Earths.
Of course it is believed that the moon formed from a debris ring after another planet collided with Earth, and such an origin for a moon of a giant planet might leave that moon without any gas.
Pluto has a mass of 0.0022 Earth, and its largest moon Charon has a mass of 0.00025 Earth, a mass ratio of about 0.1136. If a giant planet on the border with brown dwarfs with a mass of 4,134 Earths had a moon with that mass ratio that moon would have a mass of 469.772 Earth.
Of course Pluto and Charon are also believed to have formed from an impact.
At the preent time exmoons are near the limits of detectability and no proposed exomoons have been confirmed.
Most of the exomoon candidtates so far are probably more massive that Earth, and so might potentially count as superearths, gas dwarfs, ice giants, or gas giants.
[https://en.wikipedia.org/wiki/Exomoon#List[3]](https://en.wikipedia.org/wiki/Exomoon#List%5B3%5D)
And if there are ever confirmed moons of Earth mass or greater orbiting objects confirmed to be planets instead of brown dwarfs, the planet to moon mass ratios in our solar system will be shown to be medium values insted of extreme values.
I note that Titan, the largest moon of Saturn, has a mass of 0.0225 Earth, between Callisto and Ganymede, the largest moons of Jupiter, with masses of 0.018 and 0.248 Earth respectively.
Their escape velocitiea are Callisto 2.440 kilometers per second, Titan 2.639 kilometers per second, and Ganymede 2.741 kilometers per second.
Since Titan is farther from the Sun and colder, it should have a slightly better ability to retain an atmosphere than Callisto and Ganymede do.
But the atmosphere of Titan is literally billions of times as dense and has literally bilions of times the total mass as the atmospheres of Callisto and Ganymede. And the reasons for that difference are not known as far as I know.
So if two exomoons with identical mass orbit giant exoplanets and recieve the same amounts of radiation from their stars, one could be a basically airless rock and another could have an atmosphere many times as dense at Earth's and perhaps count as a gas dwarf, depending on varius factors.
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I was wondering, if a planet in similar size and mass to earth would have, from its creation, been spinning at this hypothetical planet speed limit (with it somehow staying in once piece) could life still evolve with the conditions that seem catastrophic to us?
(huge disk shaped equator, from what I gather, and extremely intense winds)
And more importantly, could they even begin to launch space-ships, or would the terrible conditions keep them bound to the ground?
The context I am using is, Imagine that a probe travels to the planet, would it just be a big blur? And could the probe accelerate to the speed of the planet and orbit it?
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It is an interesting question. Firstly, because of the science-based tag, it is unlikely that any planetary body could rotate at anywhere near the limiting rotational velocity. Most planetoids in the solar system have a period more than about 2 hours - anything faster is generally very small (sub 1 km) although there are a few exceptions ([one object 400 km in diameter with a 30 minute period is listed in a wiki article](https://en.wikipedia.org/wiki/List_of_fast_rotators_(minor_planets))). It is not obvious how normal planetary creation or even a violent collision could give an earth-like body anywhere near that rotation rate.
But allowing for some wierd natural phenomenon (or artificial means of spinning up), a rapidly spinning body can form into a [stable oblate spheroid or a rod-shape or a multi-lobed structure (or even a torus)](https://www.science20.com/robert_inventor/so_you_thought_you_knew_what_planets_look_like_shapes_of_rapidly_spinning_planets-155538).
Assuming the oblate spheroid option, the maximum stable spin is when the surface gravity at the equator is equal to the centrifugal force on an object at the equator. That means that a body at the equator is (almost) in geo-stationary orbit. Any faster and the planet will fly apart.
I don't have the maths tools here to do a detailed calculation but for the earth, I believe the limiting obaticity is around [3:1](https://www.forbes.com/sites/startswithabang/2017/02/14/how-flat-can-a-planet-be/#d8f1ac735fad) so the earth would have a radius of ~11000 km at the equator but only about 4000 km at the poles. It would be rotating approximately once every four hours.
Effective gravity at the equator (that is the sum of the effects of gravity plus centrifugal acceleration) would be almost zero - i.e you would be nearly weightless. At the poles gravity would be about 2/3 of what it is on earth. Interestingly though, on the oblate spheroidal surface, the local 'down' would still be perpendicular to the surface at every point (assuming the planet was in hydrostatic equilibrium) - although the horizon would appear much closer at the equator and much further away at the poles compared with Earth.
With regard to intense winds etc - the rate of rotation and the oblacity wouldn't in themselves cause excessive winds - but they would likely result from a combination of solar radiance (heating the atmosphere) and the Coreolis effect (which would be much greater than that which we experience on Earth). But whether this would cause mega hurricanes, or rapidly circulating latitudinal air-flows like you see on the gas giants is in the realms of exoplanet meteorology so I cant really comment. In principle there is no reason why the atmosphere might not be relatively stable.
On other effect of this oblacity is that if there was a significant axial tilt like earth's then the seasons would likely be a lot more extreme - as the poles would have a surface far more oblique to the sun and the portion of the planet s surface that could be considered 'polar' would be much larger.
No obvious reason why a hardy intelligent species couldn't evolve in these conditions. And they have the bonus that if they can, their rockets would have a much easier job taking off - so long as they built their space-ports at the equator.
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It is probably not possible for a planet to be rotating at near the structural limit for long enough for intelligent life to evolve. The earth had a day of around ten hours right after the moon was formed, but the [tidal effects of the moon and the sun](https://en.wikipedia.org/wiki/Tidal_acceleration) slowed it down to its current 24 hours, and it is still very gradually slowing. Even without a moon, the parent star would have noticeable tidal effects (for the sun, it's 46% as large as the moon's effect).
The tidal effect would be weaker if the planet were denser and hence smaller.
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*Hello! I'm no scientist so I've reached the limit of my knowledge. I was wondering if any of you smart beans out there would be able to help me figure this out? Here are the specs of my system;*
Kereiol is a 2 billion year old quiescent carbon-rich M star with a temperature of 3,100 kelvins. If it flares at all they are tiny. It has four orbiting planets, only one of which, Liskuel, is within the goldilocks zone. Liskuel is 0.15 AU from Kereiol and has an orbital period of 35 days.
Liskuel is a tidally locked wet, rocky carbon-born planet with an active core. It is 1.5 times the size of earth, but with a similar mass and gravity as unlike our planet which is dominated by oxygen and silicates, it is rich in aluminium, titanium, silicon, carbon, and lithium and mostly comprised of quartz or diamond. 70% of the surface is covered in water, with especially deep oceans on the nightside.
I'm thinking the range of plants; plants closest to the nightside reflect the peak radiation to use other less intensive light and appear black while plants closer to the substellar point use chlorophyll f and infrared light and appear a reflective bright blue-green metallic. Could there be other colours? Would these colours be possible?
*Cheers!*
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The short answer to your question is that your plants *could* be any colour, but that is a massive over-simplification of the processes that lead to plant colours being what they are. I'll go through some of the basics though to spell it out in more detail.
**Visible light is only 0.0035% of the EMR spectrum**
For a start, the plant colours we see today are based on the fact that we only see a [very small fraction](https://www.quora.com/What-percentage-of-the-light-spectrum-are-humans-able-to-see-with-their-eyes) of the possible spectrum of light. The beauty of this for us is that it gives a massive differentiation between night and day for us, and if we could see in the entire spectrum the difference would not be that discernible at all. To apply this to your plants on your planet, given that the source of light isn't that bright by comparison to our star (albeit it's closer) then it's more likely that your plants will have evolved to capture far more of the spectrum than terrestrial plants. Also, your animals have likely evolved to see more of the spectrum as well, meaning that they probably see the plants in colours we simply don't have names for.
**Plants will be the inverse colour to useful light**
Ultimately, photosynthesis is an endothermic reaction. That means, that the plant is actually absorbing the light of certain wavelengths and harnessing the energy through chemical conversion. Sugars and oxygen are effectively so energetic when put together because that energy has been harnessed by the plant that way in the first place. Of course, what that means is that the plant won't reflect the energy it absorbs; only the light that it doesn't. It's that reflected light that gives it its colour. You already know that, but the general rule you need to remember here is that the darker the overall colour of the plant across the entirety of the spectrum, the more light it's aborbing for photosynthesis. Therefore, it's unlikely that your plant will be a light colour, especially white, in any segment of the spectrum as it would mean it's reflecting back far too much energy for photosynthesis to occur.
**Earth Based Life Bias**
Perhaps most importantly, all this assumes an evolutionary path on your planet similar to that of Earth. It's entirely possible that life would evolve down a different path entirely other than photosynthesising plants and animal 'parasites', consuming the plants and eventually each other to harness that energy the plants create. Certainly, if the planet doesn't get a lot of strong light it's just as possible that eyes don't exist on your planet and that animals get around with a sensitive and precise sensory package that relies on an equivalence of smell. In such a case, the plants may well be black because that way they can harness the entire spectrum, but may emit other chemical pheromones or beacons to let the animals know where they are, especially if they have flower analogues to pollinate, or fruit analogues to eat for seed dispersal. The point being, we can't know exactly that light or colour even matters on this planet in terms of the local ecosystem.
So, your plants *could* be almost any colour, but they're far more likely to be darker than lighter, and I'd argue that they're also more likely (especially given the tidal lock) to use a much larger percentage of the EM spectrum than our own visible light range, meaning that if there are creatures there to see them, they are probably some dark colour for which we could never possibly have a name because we wouldn't be able to see it properly in the first place.
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I'm trying to figure out a way to make this species as I envision it while still maintaining scientific realism. I want to get it as close to "yes, this could exist in the real universe" as possible. If you want a quick visual primer: something like [this](https://i.redd.it/rfjod7z299421.jpg) or [this](https://i.imgur.com/M7CBzXM.jpg) - but with wings capable of flight and tail. I'm not an expert in biology or astronomy, so everything below is up for criticism. Thanks in advance!
My rough draft of their origin is: they are descendant from an ancient dragon-like being that was killed long ago, its remains preserved and left adrift in the vacuum of space. Eventually it's captured in the gravity of a young, habitable planet and plummets to the surface, where a panspermia-type event helps to create new life. Evolution does its thing over the course of many, many years, and sooner or later come this race, evolved in the image of the original creature. How far along the planet was in its development I'm not sure, but they are meant to be the first sapient species on the planet. Again, all of this is subject to change based on my lack of expert knowledge.
Here are some basic traits that I'd like - with diet and genetics playing a factor when appropriate.
* **Height**: An average somewhere around 6'8" (2.03m) - 7'2" (2.18m)
* **Weight**: Anywhere between 200-350 pounds (90.7-158.8kg)?
* **Basic anatomy**: Bipedal, humanoid anatomy - does it make sense that they would be upright, humanoid creatures without the presence of humans? With three fingers and a thumb for each hand. Digitigrade or plantigrade feet with three or four toes.
* **Lifespan**: ??? - I could use some help with this one - not sure how much of a factor all of these different traits would play into the average lifespan.
And for some more complex features...
* **Wings**: Made of a durable and light material, but not sure what exactly. Capable of powered flight, ideally - would this be possible without violating square-cube law? Ideally capable of providing enough lift to fly anywhere, but gliding once jumping from a high enough area could also be an option. Maybe a second pair of lungs that stores lifting gases like hydrogen.
* **A tail**: For stabilization during flight. Length and thickness will vary with genetics and diet, but typically as long as or slightly longer than the length from waist to feet. Serrated ridges along the top for protection and to use as a weapon. Would the tail be an extension of the backbone, or would it have its own vertebrae and ligaments?
* **Fire-breathing**: Could maybe have glands somewhere that store flammable gases like octane or methane, plus some sort of oxidant and ignition mechanism. I think this is the one that I need most help with, not too sure about the anatomy of storing all the required parts.
* **Horns**: Just because I want them! Their shape and size would be determined mostly by genetics. Protruding out from either side of the forehead and can curve while growing. Useful for protecting the head.
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There's a few interesting things possible here, but let's get something out of the way. Powered flight is *impossible*. I mean, okay, if you play around with atmosphere and gravity it isn't, but as it stands now, it's completely impossible. Like you said, it violates the square cube law. An upright reptile averaging 6'8" to 7'2", realistically, is going to average around 300 pounds, maybe more. That means massive, gargantuan wings, which take massive gargantuan muscles, and you'll end up less with dragon-like humanoid and basically a pair of wings which happens to have a face on it.
Gliding is more realistic, and if you feel like it, settle them on some kind of volcanic world with plenty of updrafts from lava pits that they'd be able to ride. The wings in question would be giant flaps of skin, normally locked to the dragonoids back, which they'd be able to snap into a giant framework, giving the dragon a pair of massive sails. (I'd assume cartilage would be involved in this framework - more flexible than bone, more rigid than just flaps of skin.)
A tail - reptilians tails are an extension of the spine, in general, so I'd assume this would be no different. They also tend to be strong.
Fire-breathing - there's already a few answer to this, apparently. If you're looking for anatomy to copy, I'd recommend taking a look at [spitting cobras](https://www.aboutanimals.com/reptile/spitting-cobra/).
Horns - this is really the easiest. Horns are made out of keratin, the same stuff human hair is made out of. Except that keratin usually crops up in creatures that have hair, aka mammals. So, if you want to keep to the reptile theme, these would actually be bone horns. (Well, keratin horns are also made from bones, but there's only a small nub, than keratin grows around it. These would be entirely bone. Probably hurt a lot if it breaks.)
Lifespan - tricky one. Reptiles are basic lifeforms, but these are advanced versions, lots of complex parts. Throw it a fully developed autoimmune system, and add natural armor. Not as long as a human, but not significantly shorter. Probably around 60 years.
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The hippotragines are a small subfamily of antelopes that bear physical resemblance to horses. There are three separate genera--*Hippotragus*, *Oryx* and *Addax*. As grazers, rather than browsers, the "Hippo" in Hippotraginae refers to the slightly horse-like characteristics of body size and proportions: long legs and a solid body with a relatively thick muscular neck. What's more, they are built for environmental extremes and live lives that might be suitable for domestication:
The Arabian Oryx, as the name suggests, lives in the hostile deserts of the Arabian Peninsula, and it lives in mixed-sex herds of 2-15 (though herds numbering 100 have been reported.)
The Scimitar Oryx can go for a long time without water and can even thrive in temperatures too high for most other mammals, hence their natural location in the Sahara Desert.
The Gemsbok lives in herds of 10-40, led by one dominant male alongside a few other subordinate males.
The Addax gets all the moisture it needs from the plants it eats and, like the Arabian Oryx, lives in mixed-sex herds.
So the question is, can any of the listed species be suitable alternatives for horses in the art of domesticating for the sake of cavalry? Or do they have personalities that would make domestication not worth the effort?
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**TL;DR: Probably not, but you could still make it work if you played around with human history enough.**
Most anything can be domesticated, and the criteria for early people domesticating an animal really boil down to economy rather than behavior, which changes as both sides gradually adapt their lifestyles around each other. It also heavily relies on culture: not every animal that can be domesticated will be domesticated, otherwise we'd see independent events all over the place very early on.
It's important to note that the first domesticated megafauna were not ridden or put to harness. Even horses were simply livestock in the beginning. After some generations, they became more amenable to carrying packs or even pulling things, and horses developed strong enough backs to be ridden for longer periods of time.
Riding, specifically, will require a minimum wild-type weight to be physically possible. Most animals seem to be able to comfortably carry 20-30% of their weight; this is true for horses, llamas, goats, and dogs. I can't find anything immediate for cattle, although [yaks carry about this percentage for long distances](http://www.fao.org/3/ad347e/ad347e0g.htm) and can carry nearly their entire body weight for short trips.
Usage in battle *may* require a social structure that allows themselves to follow the herd and listen to the rider in stressful situations (donkeys lack this, and will freeze up or flee a battle). And the additional economic factor here would be their performance: speed, stamina, agility etc.
Now, let's look at your antelope. The Arabian oryx and addax are immediately out; a wild Arabian oryx would barely exceed 200 lbs and the heaviest addax barely reaches 300. This is smaller, on average, than the guanaco whose maximum weight goes just over 310. Even llamas, slightly larger, can only carry about 90-100 lbs.
Your strongest contenders for weight are the gemsbok (460-530 lbs - max weight for females vs males) and the scimitar-horned oryx (309 - 460 lbs). The wild-types of both animals are still too lightweight to support a fully grown human. With sufficient selective breeding, they may reach such a size, though it might be difficult. It's hard to find trustworthy data on tarpan *weight* per se, but a description of the [height of the last living tarpan](https://books.google.com/books?id=I4BVDgAAQBAJ&pg=PT95#v=onepage&q&f=false) was measured at about 13 hands, which means we can make a [semi-educated guess](http://www.equine-world.co.uk/horses_care/horse_body_weight.asp) it weighed anywhere from 638 to 770 pounds.
So, both of those will have an even larger curve than horses, but potentially within the range of possibility. The most realistic path to reach this weight would be if they were first bred for food, then pack (or both), potentially even draft (not an option if you already have cows), and bred for size on all of those factors before someone has the insane idea of breaking one to ride.
Both the scimitar oryx and gemsbok seem to have appreciable herd structures; they're very similar to how horses and cattle conduct themselves. They definitely appear very close knit and could be efficiently herded, make good caravans (though, again, donkeys got by for both of those without having such a strong herd structure) and may conduct themselves well enough in war assuming one was large and strong enough to ride.
It would be a stretch, but I'm not saying it's impossible. What will complicate things is that looming economical factor. IOTL, we already had goats and cattle for food and labor. The oryx was only tamed for ceremonial use and for show, though I'm sure it was eaten at some point. Since you won't be able to use these antelope for riding immediately, you'd need them for the same roles already occupied by other animals that have already been domesticated. People will trust an ox over an oryx to pull a plow or transport goods, would rather milk a goat than a gemsbok cow, and will just generally have an easier time with their domestic animals than the wild ones, forgetting entirely what it was like when their ancestors were first making use of the aurochs and ibex. Get rid of those, you might see them with other animals.
If you want to domesticate antelope, you're not exactly limited to these guys. There are other antelope slightly larger, such as the roan, sable, kudu, and wildebeest, and at least two large enough to ride already: the nilgai and eland. Those two I think have the best chance, and I've written very favorably of elands myself in [this post.](https://worldbuilding.stackexchange.com/questions/139231/alternative-to-horses-in-a-dry-climate/139300#139300)
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**Two of them are too small for cavalry, and one was domesticated.**
**But the problem for the others is IF they can be domesticated**, there are quite a few traits an animal needs to be domesticable. Even in equids, horses have been domesticated but zebra have not, despite many attempts. To be domesticated prior to industrialization an animal needs the right combination of traits; the right kind of herding behavior, the right kind of mating strategy, the right kind of territoriality, the right temperament, and the right diet. Without the right combination, you can't breed them in the first place. Very few animals have this perfect combination, and they are the ones we have domesticated in antiquity.
In African plains animals, it can be even harder because many have evolved to respond to humans aggressively because they evolved alongside humans. You need animals that will **tolerate humans** being close by.
Animals especially prone to running from anything that startles them (**spooking**) can't be domesticated because trying to shepherd and pen them results in the animals exhausting and/or injuring themselves, sometimes to death.
On the other hand, an animal that will attack other animals in its pen even if otherwise docile is common. They won't be domesticated because it is not economical if each animal needs its own field the sheer amount of land needed makes it impossible. Many herd animals will not tolerate new members this makes breeding particularly difficult.
An animal that is overly **aggressive or dangerous** will not be domesticated because of the risk involved, zebra are an example, the Dutch Boers tamed them by the hundreds and tried for decades to domesticate them, but they would attack their keepers biting and kicking seemingly at random making handling them too risky. Modern zoos even have special handling instructions because you never know when a zebra might decide to attack. Similarly, you can imagine why domesticating lions never happened, it's hard to domesticate something that might decide to try to eat you if it misses a meal.
**Now for the specific animals you are asking about.**
**The scimitar oryx actually was domesticated in Egypt** or they at least made an attempt. depictions on the Tomb of Ty and Abydos. They were used as food, leather, and a sacrificial animal, they are too slight to make good riding animals. The new kingdom gave up keeping them although no one knows why, likely they just were not economical. The also tried to domesticate hyena, but if zoo behavior is any indicator they proved too aggressive to be worth it. There is one obvious problem the length and cure of their horns means that the horn is basically pressed against the riders chest, not a great thing in a combat animal. If the rider leans forward they are serous risk of impalement or losing an eye.
**To ride an animal any distance you need a big animal**, generally, you want something that outweighs humans by several times. Even donkeys, the smallest domesticated riding animal, weighs 2 -3 times what a human does, the wild ass weighs around 500lbs, although we have bred smaller non-riding ones. The **Gembok** is the only one on your list large enough to breed for cavalry riding but it has several issues, it has highly territorial and aggressive males (towards humans and each other) and the females also spook easily. So the females are panicking while the males are trying to kill you. People may tame individual ones but they are not going to keep a breeding population.
If you handwave their behavior, (maybe your people found a family of mutants), then yes the Gembok could be bred for calvary. Physically they would work fine, it is only their behavior that makes them unlikely candidates.
[Introduction to domestication](https://onlinelibrary.wiley.com/doi/abs/10.1002/evan.20101)
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Given enough time and effort, any of these hippotragines could be bred and trained (and it takes both of these things) to make something akin to cavalry.
But your question actually seems to be whether it would be worth the effort. If you have access to anything already domesticated capable of carrying anything, the answer is probably no. I actually think you would be better off trying to selectively breed cows for this rather than starting with these wild animals.
But if nothing else is available, lets try and work out how much effort it would take.
The Russian fox experiment took 30 generations to become domesticated. In real terms, this means that the offspring would consistently not rip your face off given half a chance.
So an oryx female breeding age starts at around two to two and a half years old. So at **best**, with gestation, 30 generations would be 90 - 100 years.
So after 100 years of effort, you have something you can start working with, train etc. and only now can you begin selectively breeding for size and other characteristics.
Other factors you may need to consider are:
* how many of these animals you have to begin with (currently some oryx species are on the endangered list)
* luck, most of the foxes in the Russian foxes relate back to one female with a good temperament produced early on in the experiment
* amount of people to breed and test all of these animals for suitability to add to the next generation
But honestly, I think most people would give up before 100 years.
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> A Suitable Alternative For Actual Horses?
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Of course they are, assuming domestication & selective breeding is involved then *any* suitably sized quadruped is, if the time it takes to selectively breed to make them large enough doesn't matter then we can even throw out "any size" & just say any quadruped, mouse cavalry anyone?
There are only two possible reasons they might not be.
1. Their skeletal structure may not be suitable for carrying heavy burdens (aka an adult human) for long periods of time without causing them injury.
2. Their temperament & tractability may be unsuitable for training.
But neither of those potential problems matter because both can be addressed by selective breeding & the domestication process.
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> can any of the listed species be suitable alternatives for horses in the art of domesticating for the sake of cavalry?
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All of them are suitable, though some of them may need to be bred to be a bit larger.
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> Or do they have personalities that would make domestication not worth the effort?
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Any problem with personality in the species will normally automatically be bred out of them by the domestication process, if still a bit intractable then more selective breeding can always fix it.
*The only thing that tends to make domesticating a new species to serve as a mount not worth the effort is the prior existence of an already domesticated animal used as a mount (aka horses) which does make domesticating a new species for the same use a little bit like reinventing the wheel.*
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To be perfectly clear wild animals are not domesticated even if they are [tamed](https://en.wikipedia.org/wiki/Tame_animal) & [trained](https://en.wikipedia.org/wiki/Animal_training) to perform tasks or tricks, that isn't domestication & they are still wild animals, [domestication](https://en.wikipedia.org/wiki/Domestication) is something else entirely & is only achieved over several (normally a great many) generations of selective breeding.
Some wild animal species may be easier than others to tame & train but that does not make them domesticated & the word domesticated is misused\* when referring to a tamed wild animal.
*\* A prime example of this misuse is the many articles you'll find if you Google "domestication zebras", there has never been an attempt to properly domesticate the zebra & if you read the articles (rather than just their titles & first few lines) you find in every case that what they're really talking about are attempts to tame & train wild zebras to saddle or harness, not comprehensive breeding programs.*
A good example of the real domestication process is the Russian [Domesticated red fox](https://en.wikipedia.org/wiki/Domesticated_red_fox).
Any species can be domesticated given enough time & it is in this context I answered the question.
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# Given 5,000 years of selective breeding, I'm sure you could.
That's the trouble with replacing horses, they've been domesticated pack and riding animals for a very long time. They've been bred to be the perfect pack/riding animals for humans.
Could you replace them with another quadruped? Perhaps with any other quadruped given sufficient years of selection. Though we've previously discussed the need to avoid using predators as mounts, mostly due to the inefficiency of feeding them.
It helps that they're herd animals, that means they have the right sort of group mentality that can be exploited by humans. They're all too delicate in the body and fundamentally too flighty as wild animals as they are. By the time you've finished breeding them for strength and temperament you'll probably have something that looks a lot more like a domestic cow or ox than a deer.
The question isn't really "could they be domesticated" as "is there something better"? Deer and antelope as a general rule haven't been worth domesticating, they're too difficult to work with when there are stronger and more passive animals available. You're talking about taking on a project that's going to take generations to complete, look for shortcuts to some aspect before selecting a creature to work with.
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As stated in the title: is there any realistic way to either evolve (in our evolutionary past) or acquire via genetic engineering an immune system better than what we already have?
I tried to do some research, but it looks like our current immune system is already pretty good compromise between "immunity" and "autoimmune disease", moreover any disease-specific gene mutations (like this one: <https://en.wikipedia.org/wiki/CCR5#CCR5-%CE%9432>) seem to have downsides, like increased susceptibility to other diseases.
One idea I had before was to replace adaptive immune system with whitelist-based approach, targeting every strand of DNA whose checksum fails to comply with anything on a fixed whitelist - but then we would need somehow to make humans independent from any symbiotic bacteria, and severely limit the population gene pool (because "too different" embryos would be killed in the womb). So, not really a good idea, right?
So, is there anything that could be improved? (and how?)
Edit: I am asking only about some inheritable biological traits, like (positive) mutations, not something that may be received during the lifetime, like drugs and vaccines.
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**Augment immune defense against cancer by altering the PD-1 system.**
In the past 5 years there has been an enormous surge of interest in augmenting the immune system against cancers. Certain cancers evade immune attack via a molecule called PD-1, which provides cells with a sort of diplomatic immunity. Cancers hijack this system. If you block PD-1, many cancers become susceptible to immune attack.
<https://blog.dana-farber.org/insight/2015/05/the-science-of-pd-1-and-immunotherapy/>
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> The groundwork was laid in the 1990s, when scientists learned that
> human cells carry certain proteins on their surface that enable them
> to escape attack from the body’s immune system. That was followed by
> the discovery by Dana-Farber scientists that many cancer cells wear
> one of those same proteins, called PD-L1 – part of an elaborate
> masquerade that allows the cancer cells to live and multiply without
> harrassment from the immune system.
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>
> The implications of that finding, published in 2001, were
> self-evident: find a way to block PD-L1, or the proteins on immune
> system cells that “see” PD-L1, and the command that once prevented an
> immune system attack on cancer would be lifted.
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Drugs that operate via this mechanism are now approved and in use against many cancer types. Currently these drugs are approved for treatment of existing cancers, but efforts to use them for cancer prevention are underway.
People sometimes get autoimmune disease when they have the PD-1 system blocked. But if you altered that system to still protect normal cells to some degree but make it less easy for cancer cells to counterfeit, an effective immune response might prevent these cancers from getting established in the first place. If you are going to rejigger the immune system genetically, that would be a rational place to start.
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You mentioned a whitelist-based approach. Fleshing that out, you would need immune cells to read dna/rna of every cell (how to access that without harming good cells?), calculate the \*NA's checksum and compare it against a whitelist (one copy stored in each of these cells). Then they could let the processed cell pass or mark it for destruction.
If you consider that to still be realistic, you could swap out the checksum+whitelist mechanism for a species/clade-detection+whitelist one. Ideally, the level of clade stored could vary, so that all mammals are okayed (if you have foreign mammal DNA in your body, it can only be your own child or a transplanted organ), but rogue strands of originally benign bacteria can be weeded out.
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I have a species of humanoids that spends a lot of time around fire. They are able to spark their own fires, and they have a reasonable [fire resistance](https://worldbuilding.stackexchange.com/q/126888/47918). One problem presenting itself is smoke inhalation.
These humanoids are genetically engineered, so evolution isn't a problem. They don't have to worry about poisoning from many substances due to a modified renal system and some helpful bacteria. I am open to any changes, biochemical, etc, as long as they fit within a human shape.
In particular, I am wondering if they could inhale smoke from fire and absorb its components, such as carbon and water vapor, for use in their bodies. What changes to their respiratory system would have to occur? Could they breathe carbon monoxide and carbon dioxide?
Would the use of smoke in their metabolism just be too inconvenient or detrimental to be implemented?
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Short answer yes you could have a creature that breaths smoke but their blood chemistry will have to be more complex and flexible than what we see in the modern hemoglobic animals. They could absorb Carbon and Water Vapour from the smoke they breath to supplement their metabolism, but there are problems; Carbon Monoxide being the biggest.
If smoke was just Carbon Dioxide and Water Vapour then you'd only need a new chemical in the blood that will scavenge Carbon Dioxide and prevent it from staying bound to the hemoglobin, then break it down, this would be similar to [Chlorophyll](https://en.wikipedia.org/wiki/Chlorophyll) but use [ATP](https://en.wikipedia.org/wiki/Adenosine_triphosphate) rather than sunlight as an energy source. Water can be pulled directly from the lining of the lungs as it precipitates in them, with a little change in osmotic pressure.
Carbon Monoxide is a problem though; it's chemically different enough from Carbon Dioxide that it doesn't follow the normal metabolic pathways for Oxygen and Carbon Dioxide in the body. Instead it binds to the hemoglobin and doesn't let go, it forms [Carboxyhemoglobin](https://en.wikipedia.org/wiki/Carboxyhemoglobin) instead which can be highly toxic. To have a creature exposed to high levels of Carbon Monoxide on a regular basis you need a different basic carrier chemical instead of Hemoglobin, or a second scavenger enzyme that will preferentially break the Carbon Monoxide out of Carboxyhemoglobin; that's a much larger change in body chemistry.
There is another chemical in smoke that you may wish to consider, if you are burning raw organic material (as opposed to coal or charcoal that have lost most of their Hydrogen) there will be [Cyanide](https://en.wikipedia.org/wiki/Cyanide) in the smoke in low but consistent concentrations. You'll need your creatures to be immune to chronic cyanide poisoning if they're in an environment where growing things are burning on a regular basis.
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I am Carrion the Black Hand, lord of the Ashfields brother to Kaine!! The God king. While Kaine is busy defending against the Sun Empire's holy war, I am planning a naval invasion. The plan is to attack the Sun Empire's Golden Fleet that is anchored off the coast of the Dragon Isles, then land in White Hearth and put it to the torch. The problem is that I do not have much of a fleet to work with and less time to build a larger one. The Golden Fleet will outnumber us three to one and most of my ships are for troop transport. Now I like boarding ships and killing all the crew like everyone else but the Sun Empire know this. They will use smaller ships (Cogs) to shoot at my Galleons then move away before we can hit them, then their own Galleons will come to finish us off.
My son Ivan came to me with a solution to my problem: living in the grey wastes near Cold Harbor is a tribe called the Sea Singers. They are known for taming and riding whales, even riding them into battle with rival tribes. They have answered my call to arms and will soon arrive in Iron Port, with all 500 riders and their War Whales. They will be of great use to me in the battle to come.
I will now hold a war counsel, now my advisers i ask you: **What would be the best way to use these War Whales in the coming naval battle?**
**Info:**
The War Whales' numbers consist of mostly: Killer whales, Humpbacks. Even some Blue whales and Sperm whales (but only a few of them) and (sigh)...one Narwhal (I will add any cool Whales that get mentioned).
The Sea Singer riders can hold their breath for ten minutes at a time (I can train my own men to hold their breath for three if some need to ride with them (but only Sea Singers can control the Whales), the Sea Singers are also master bowmen and harpooners.
The smiths of Iron Port are some of the best in the world, so we can use them, if the whales need amour or some form of battering ram or better saddles.
I will just point out that there is no magic involved.
**The tech level is high medieval 1400 century**, steel plates are a thing but gun powder is not on the scene...yet
For more info about Kaine see also: [Why Would an Enemy Army Retreat if they Will Die Anyway](https://worldbuilding.stackexchange.com/questions/121476/why-would-an-enemy-army-retreat-if-they-will-die-anyway)
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I've changed my mind: Simply have the whale riders destroy the rudders of your opponent's ships. Just imagine, you have everyone you can making spare rudders as you sail off to confront the enemy navy. They face you, ready to overwhelm you, when suddenly a hundred whales pincer them from the other side, destroying their rudders one after another.
You encircle the now helpless ship, giving them two options, surrender, or die. Let your whale riders crush a few boats that are more vocal about never surrendering. As boats surrender, slowly relocate their crews to small boats to be pulled behind, keeping them in a separate place so they can't revolt.
Drag back as many boats as you can back to your port, and hide the others somewhere that you can recover them later. Rush home quickly and have new rudders installed on the larger vessels. This is where all those rudders you had built become important.
Now you have the enemies fleet all to yourself, and you can sail it straight back to them. Since the battle should have taken a while, no one will be suspicious when it takes a while for the boats to return. Except as soon as you land in the harbor, you turn their own vessels against them, landing your troops and turning any weapons they had against them. Boom, you've turned their own asset into your asset, shifted the tide of war easily, and made a military maneuver that will literally go down in textbooks.
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Whales can easily destroy boats, just have your whale riders swim underneath the boats and flip them over or smash their hulls, both by landing on them after jumping, and smashing them from below. Killer whales are faster and should aim for small vessels or escape boats, and blue whales should target major vessels. Save the sperm whales as a back up in case reinforcements are spotted, and then give orders accordingly. Take no prisoners unless there is a complete surrender, in which case capture the boats that you want, and sell off the ones you don't need. POW can be used as collateral to get reparations after you win, if you aren't planning an annexation. If you are, then just take no prisoners to begin with.
Addition: Mostly sperm whales sink ships, but it's reasonable to assume any whale can sink a wooden ship equal to its length.
Bonus: You should have one guy who rides a narwhal because it "looks cool" even though it's nowhere near as powerful as the other whales.
<https://www.whalingmuseum.org/learn/whale-attack>
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My species of caniform-like creature has a relatively long muzzle because of its strong sense of smell. I would like to know how to give it a long muzzle with its large brain size. Members of this species primarily communicate with each other through certain electromagnetic waves, bodily scent, and occasional sound such as clapping or yelping. This species has relatively poor eyesight with red-green colorblindness. They are bipedal and have opposable digits on their forelimbs.
As well as being scientifically inclined at the level of modern day humans (of course with technology catering to its own forms of sensory input), members of the species would be able to understand many human concepts, form cultures, and create complex, intelligent concepts of their own. To put it bluntly, this species has 'intelligence' on par with humans.
More to the issue of the muzzles; this species does not hunt with a powerful bite because of tool use. It does have a mesocarnivorous diet with the appropriate dentition, so if anything about the diet would influence musculature, please indicate so. Regardless, I would expect it to require more muscles to support its snout. Neck muscles would already be highly developed because of the horn-like antennae on this creature.
Assuming the musculature of the mouth is much like that of existing carnivorans, for the most part, I am wondering:
* If the muzzle is at all plausible with a large brain
* If the muscles of the snout just be too heavy or large for the head
* If any 'space saving' adaptations such as putting brain tissue in the spinal area would work
* If the head would be too ridiculously large to support at all
I hope this is clear enough.
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A plausible reason for the negative correlation between anthropoid muzzle size and brain size is quite simple, the higher the intelligence, particularly if high enough to ***cook***, the less need there is for large teeth, chewing muscles, or heavy support in the skull. When teeth stop being your primary weapon (offensive or defensive), and no longer have to crack hard shells or masticate on raw vegetables, when tools and fire replace those functions, the evolutionary need for heavy jaws, a powerful bite, and large teeth is much reduced.
And evolution is efficient in the long run; use it or lose it.
I will present a counter-example, another mammal with very high intelligence, with apparent consciousness, tool use, cooperation and a rather large muzzle: Bottlenose dolphins. There are numerous experiments suggesting they have an abstract language (more than specific nouns or verbs, a descriptive language that allows them to describe procedures or objects they haven't seen before to another dolphin). I think there is no debate they are highly intelligent, provably inventive to solve problems, which to our knowledge requires self-awareness in a biological intelligence. (Solutions can be found by computers by simulating millions or billions of trials and errors, but no biological intelligence works that way, certainly not humans or mammals).
Elephants are likewise highly intelligent, problem solvers with self-awareness; and the elephant's trunk is an extended version of a nose.
There is also strong scientific doubt about correlations between brain size and intelligence. The vast majority of brain size is most strongly correlated with body-size, much less so intelligence. Large bodies have more nerve endings for both sensory functions and muscle command, and for processing the larger number of incoming signals. Due to accidents, gunshot wounds, cancers, strokes, etc, some unfortunate humans have lost nearly half their brain mass, and still recovered to be walking, talking professionals with above average IQ.
Large brains do not correlate with IQ; the average human brain is 3 pounds, and the average elephant brain is 4x bigger, at 12 pounds. And although elephants make and use tools and have a complex social life, if they were 4x as intelligent as humans, or 1x as intelligent, they would not be an endangered species and like the first homo sapiens would carry sharp weapons against predators.
You should consider relative brain mass (as a percentage of the rest of their body mass), not total brain mass; and as humans (both injured and whole) prove, there can be a factor of two or three even in that relative figure.
***I think a large muzzle and intelligence are evolutionary compatible.***
It is a large mistake, IMO, to short-change evolution and consider only the single human path toward intelligence, self-awareness and abstract thinking.
Evolution will find a way to solve any problems. That said, your creatures should not have features just because you think they'd be cool, you need a **plausible reason** a large muscular muzzle is NOT discarded over millions of years, it must have a plausible survival value that cannot be replaced by brain power -- and nearly all muscular functions *can be*. Compared to other creatures we dominate (including others like us, chimps and gorillas) we are weak, poorly sighted, slow, absent natural weaponry like teeth and claws, with seriously deficient hearing and olfactory senses, all in large part because abstract reasoning easily trumps all those tools, and we have *declined* from the "size and senses matter" body plans to our current state because we don't really need all that muscle. That is not a one-example rule, dogs have done the same, they may be descended from wolves but most domesticated dogs could not keep up with wild wolves in hunting or battle even if born to the life; they evolved away from that because they don't need it.
Simply needing a long snout to preserve the olfactory sense is not enough; it doesn't explain the need for a muscular jaw, large teeth or heavy jawbones. The elephant has a fine sense of smell without a bone in its nose, many fish have superb olfactory senses in very small packages, as do short-snout and very small dogs.
I won't propose any solutions, that is your creative job, but if there is a good plausible evolutionary reason to have both of these features together, I would presume that evolution would find a way.
[Answer]
If the main reason for a muzzle is the olfactory sense, you might want to look at skulls of polar bears. They have one of the strongest olfactory sense among animals, but their muzzle isn't overly long. Instead, the nostrils are quite wide and the tissue heavily folded to get more area to have more olfactory cells in a limited space.
The skull offers enough space for a large brain without the need for big muscles to hold it up.
Balancing heavy horn-like antennae could pose a problem because they shift the center of balance. So the strength of the neck mainly depends on your design of their antennae.
[Answer]
Assuming the musculature of the mouth is much like that of existing carnivores, for the most part, I am wondering:
```
If the muzzle is at all plausible with a large brain
If the muscles of the snout just be too heavy or large for the head
If any 'space saving' adaptations such as putting brain tissue in the spinal area would work
If the head would be too ridiculously large to support at all
```
This answer will deal specifically with the relationship between brain size and a muzzle. Viz., Is the muzzle of a carnivore plausible with a large brain? The simple answer is no. This can be demonstrated by looking at [human evolution](https://sci.waikato.ac.nz/evolution/HumanEvolution.shtml).
This will be a simplified picture of that evolution, but this should suffice to explain the general principles involved. Essentially over the period humans from ape-like primates to modern humans cranial capacity, i.e., brain size increased while the size of their jaws decreased. Our oldest ancestors possessed prognathous jaws or what can be called basically big jaws that stuck out from their faces. This is the equivalent of a muzzle. By comparison, modern humans have flat faces and small jaws along with a greatly increased brain size.
Essentially hominids with large jaws had small brains. As they evolved into humans brain increased and jaw size decreased. Basically cranial capacity was constricted by the large muscles needed to support their large jaws. Modern humans' big brains and small jaws were anatomical features that co-evolved to make us human.
[](https://i.stack.imgur.com/cp7qj.jpg)
Source: [Human Evolution](http://www.passbiology.co.nz/biology-level-3/human-evolution)
In the early days of human evolutionary studies there was discussion whether hominids evolved their big brains first or if the size of their protruding jaws became smaller first.
The Piltdown Man forgery was an unfortunate distraction to progress in the understanding of human evolution.
>
> The "large brain first" view received further support when the Piltdown fossils were presented to the world. While we now know that they are fraudulent, at the time (1911) they seemed to demonstrate quite clearly that early humans had a modern cranium atop an ape-like body. And since the Piltdown remains were found in England, they conveniently supported the prevailing idea that modern humans had evolved in Europe, rather than in Africa.
>
>
>
This made acceptance difficult that humans evolved from more apelike creatures that progressively lost their more apelike features especially their prognathous jaws and their acquisition of less muzzle-like lower faces.
>
> Consequently, when in 1924 Raymond Dart recognised the position of the Taung baby (Australopithecus africanus) on the human family tree, his ideas initially faced considerable opposition. Not until more australopithecine fossils were discovered did his recognition of A. australis as a hominid gain credence. However, it is now accepted that the ancestors of modern humans evolved in Africa and remained there until perhaps 1.5 million years ago, when Homo erectus populations left Africa and moved rapidly across Europe and Asia.
>
>
>
Consider *Australpithecus afarensis* as an illustration.
>
> The best-known member of this species is "Lucy" , discovered in 1974 by Don Johanson & Tom Gray and estimated to be around 3.2 million years old (afarensis lived from 3.9 to 3 million years ago). This is an important find as the skeleton is remarkably complete for its age (40% complete by some estimates, but this does not include the bones of the hands and feet), providing a wealth of data about her size, posture, and gait.
>
>
>
Generally their sizes in terms of body height and brain sizes are as follows:
>
> Afarensis remains indicate that the species was strongly sexually dimorphic, with males much larger than females. The remains indicate that afarensis heights ranged from 107 to 152 cm, and cranial capacity from 375 cc to 550cc (AL 444-2, a large adult male).
>
>
>
With the following facial and cranial features:
>
> The face and cranium of afarensis was ape-like: a prominent brow ridge, low forehead, and a prognathous muzzle that lacked a chin. The teeth are intermediate between ape and human: the molars are large and the canines, though much smaller than those of living apes, are larger and more pointed than those of humans. The shape of the dental arcade lies between the human parabolic form and the apes' rectangular shape, and the foramen magnum, while further forward than in apes, is not directly under the cranium as in humans.
>
>
>
Interestingly the rest of their skeletons show features much more akin to a modern humans' than an apes. Although there are indications that they spent time in trees.
A summary of the differences between our *Australopithecine* ancestors and ourselves.
>
> Australopithecus
>
>
> Foramen magnum more forward –Australopithecus is mostly bipedal but
> relies on nuchal crest / neck muscles to keep head upright.
>
>
> Homo Sapiens (us!)
>
>
> Foramen magnum is centred under the skull – H sapiens is fully bipedal
> with head balanced on spine.
>
>
> Skull Human
>
>
> rounded brain case (enlarged brain) with reduced sites for muscle
> attachment, especially those used for chewing and aggressive facial
> displays which are no longer called for.
>
>
> Ape
>
>
> Flatter brain case (smaller brain) which allows for greater muscle
> attachment sites needed for aggressive facial displays.
>
>
>
Importantly a carnivore with a muzzle will need greater muscle attachment sites to support that muzzle and to give it the biting power that a carnivore needs to either devour its prey or kill them. This will mean carnivores will have smaller brains.
In summary, larger brains are not plausible for carnivores with large muzzles.
**Would the muscles supporting the muzzle be too heavy or large for the head?**
This seems likely, but it is highly contingent on the size of the muzzle and the size of the brain case. Both features are antagonistic to each other. If the carnivore had both a sufficiently big enough and a big enough muzzle, then the whole structure could be very unwieldy. This isn't plausible.
In summary, yes but extremely improbable.
The **'space saving' adaptations of putting brain tissue in the spine** seems implausible. One, because brains should be as close as possible to an organism's main sensory receptors. This is a general rule of thumb biologically. Two, it doesn't seem like there's sufficient room there to house additional mass.
However, some of the larger dinosaurs did have secondary brains located on their spines. Otherwise they would have had coordination problems managing their large bodies. Possibly a series of secondary brains could be located along an organism's spinal column. This wouldn't make the creature smaller, but more likely better coordinated. Perhaps if its cortex was located in the smaller brain case needed by a carnivore, then other major neurological features of the brain could be in its secondary brains. Notionally, but not at all certain if this is biologically plausible.
Also, octopuses have a highly distributed nervous system that extends through their bodies. This suggests a brainy carnivore might have evolved to have a similar highly distributed nervous system. Then, again, only its higher executive functions might need to be housed in the smaller brain case required by a carnivore.
In summary, while additional brain matter located in the spinal area seems implausible, there are two possible models for the relocation or emplacement of additional or extended neural systems. Please note: the organism would be different from most carnivores we know. This is very hypothetical.
**If the head would be too ridiculously large to support at all?**
Actually it's the combination of a big brain and a carnivore muzzle that is, sad to say, ridiculous. This has been covered in the discussion to the second part of your question. The combination of a big brain and big jaws is inherently contradictory. No impossible, but so full of problems for the organism with other features to be a hazard to its survival.
If such a creature existed it would need other anatomical features to protect itself and to be able to support a massive head. Perhaps a bigger body with powerful musculature?
In summary, more improbable and implausible than too ridiculously large.
However, this is purely speculative. If your hypothetical carnivore had a radically different body plan from the types of carnivores we know on planet Earth, then it might possess an anatomy where the equivalent of a carnivore's muzzle was separate from its brain case. Once the muzzle and brain case are separate structures they can each evolve to considerably larger sizes. The result could easily be a sapient carnivore with both a big brain brain and big muscular jawed muzzle. It would look very strange indeed.
This answer has considered the possibility of an intelligent carnivore with a muzzle and a large brain in terms based on features found in human evolution. While offering some possibilities about how this arrangement might work, its conclusions are generally negative about this working in combination.
[Answer]
One issue in the design of skulls is ensuring the weight is kept in controllable limits, so evolutionary pressures for light weight result in voids known as "sinuses". For a fairly extreme example the skull of the T-Rex had both a very elaborate system of sinuses for mass reduction, coupled with some extreme engineering to provide attachment points for massive muscles in the jaws, and the strength to deliver bites powerful enough to crunch through solid bone.
[](https://i.stack.imgur.com/OBlpY.jpg)
*The large sinus cavities are prominently displayed here*
So in principle, there is nothing to really stop that sort of adaptation from evolving, assuming the need for a highly sensitive sense of smell coupled to high intelligence is evolutionarily favourable.
] |
[Question]
[
\*\* **\* Xenobiology expedition 'Profundity': Log entry 634 \*** \*\*
These things are remarkably tricky to study!!
Puffer lizards live on the open salt pans of Arbslex IV (an incredibly Earthlike planet), eking out an existence by snapping up the salt flies. Mostly they’re unassuming blue grey lumps on the floor, but when any predator gets anywhere near them they leap into the air and.. well.. they puff up, floating higher and higher away from the (primarily land based) predators of the salt pans before slowly deflating and landing a safe (large) distance away. When inflated the lizards exhibit remarkable lift, shooting into the air like a helium balloon that’s had it’s string cut.
As a result of this behaviour we’ve been unable to capture a live sample for testing, and so we can’t work out how the lizards are puffing up in such a way that they generate lift. We’ve found some (very badly degraded) corpses and can confirm an exceptionally light skeleton (on the order of grams for a foot long lizard) but the organ structure is anyone’s guess.
Question for you guys at HQ is **how can these lizards rapidly generate lifting gas for their escape?** If we can come up with some theories the field techs can work on non lethal capture methods, but for now we’re stuck watching these little blighters floating off into the distance.
[Answer]
They would need some way of quickly generating hydrogen gas; any form of compressed gas would need a strong (therefore, heavy) tissutal infrastructure to keep it compressed.
A biological holding tank for sodium hydroxide and [ferrosilicon](https://en.wikipedia.org/wiki/Ferrosilicon) is not very much plausible, but I don't really see alternatives.
Heated air could not be easily heated enough, and it would need to be kept hot. On the other hand, it would be easier to produce - the lizard's skin *might* resist to the required 110-130 °C - it need not be "live" skin. Then, burping small quantities of methane gas and fresh air inside the expanded sac, and igniting it by quick strokes of flint-like teeth... it would require a very delicate, instinctive balance to avoid flaring into a [grisou](https://en.wikipedia.org/wiki/Firedamp) explosion, but it might look doable.
(However, a large net falling from a sufficient height would probably ensure a capture -- unless it made maybe the lizard explode?).
[Answer]
**They are not puffing up. They are generating a negative pressure space within themselves.**
Using photographs, the estimated volume of a puffed puffer lizard is 3 liters. Analysis of skeletal bones found the bones to be an extremely strong and light beryllium / calcium mixture, with spring loaded lever-like hinges. The lizard stores force in these springs over time and on deploying them, levers its internal puff space apart. Neither air nor any other gas flows into this space. **The lizards become vacuum balloons.**
Excluding air from a space of 3L would generate a lift of approximately 3.6 grams. This is not enough to lift the lizard outright but enough to make it neutrally buoyant in air, allowing it to make a prodigious jump straight up as though weighing only a few mg. Prevailing winds at height do the rest of the work. carrying the lizard along laterally as it slowly descends.
] |
[Question]
[
(See diagram) Presupposing that a Rocheworld can even exist...
I imagine that sunlight would work more or less the same in the atmosphere of any part of an Earth like planet that was tidally locked with a duplicate planet in a Rocheworld scenario. But what about in the area between them, where the planets share atmospheres?
An atmosphere traps the sun's rays and that's why we get day light and heat etc. But that's also because the surface of the planet is bouncing it back too, right? But the area of shared atmosphere in Rocheworld does not have solid ground, so the light would go right through. What does that do for light, visibility, warmth, radiation, etc?
For arguments sake lets say that the planets are angled somewhat so both the planets can get sun rays.
[](https://i.stack.imgur.com/VdlGO.jpg)
Thank you.
[Answer]
>
> An atmosphere traps the sun's rays and that's why we get day light and heat
>
>
>
Not really.
Atmosphere doesn't trap sun light, it is practically transparent to it. Infrared radiation is absorbed by some gases, like water vapor, CO2 and CH4, also called greenhouse gases.
But gases alone are not sufficient to capture light, you need something else to capture visible photons and emit part of that energy at lower frequency. That's also why temperature is higher on the sea level than it is on top of mount Everest, because you have much more absorbing stuff.
In your case you would get the superposition of the temperature gradients, resulting in a minimum temperature somewhere midway between the two planets.
Visibility would not be much different than elsewhere, at least for the inhabitants scale.
[Answer]
I'm affraid this would not be physicaly viable for two planets to share an atmosphere.
This has been debated at length [here](https://www.reddit.com/r/askscience/comments/4llimj/is_it_possible_for_a_planets_moon_to_share_an/).
If you went over this limitation, you probably would have no effect on the light inside the planet, but you would have a **VERY LARGE** moon: the planets would have to be roughly 1000 km appart ( the earth atmosphere is around 500 km large). if you compare to the moon, it is ~380 000 km away.
The light reflected from this 'moon' would dwarf any light from these atmosphere.
] |
[Question]
[
I'm making a continent with a large valley, "the Great Valley is like a wound in the continent". Swamps are the dominant biome in this valley. It is surrounded by cliffs and inside of it I want there to be a fog that almost never ceases. It is large enough to cover from the equator to a temperate latitude where it snows. A river with many branches (like the Amazon river) goes from the north until discharging into the sea in the south.
Please answer the following questions:
* **Could tectonic plates have created a place like this?** (My explanation is that they are tearing the continent apart, and then, this valley is emerging. Thus, would also explain the mountains inside of the valley.) ***If not, what else could have?***
* **Is it possible to have mountains inside of this valley?**
* **Is it possible to have swamps dominating this valley?** (My "noob" explanation is that the snow from mountains nearby -- or even from the cliffs -- would have a thaw that fills the region with water.)
[Answer]
**no** for many reasons, a valley that size ringed by nothing but cliffs is impossible tectonically, especially if you want it to be wet. Swamps are relatively small on a global scale, the largest one on earth is only 57,915 miles². lastly single biomes cannot extend to far north/south as global wind cells are the dominant force in rainfall patterns.
To get close you may want to try something more like south america with a large mountain range on one side forcing all the moisture out of the air. this can give you mixed rainforest and swamp. You could possibly add a shallow inland seaway with lots of large islands and mangroves, that will give you the same extensive wet foggy area but it will not extend past about 30 degrees north or south of the equator. However putting the entrance to your sea at one end can keep entrance restricted to areas dominated by mangroves and push it a bit farther.
you can look at Mount Roraima for ideas about how to put a strange mountain in the center. Isolated mountains are fairly easy to have especially if they are the result of erosion or a hotspot.
[Answer]
A valley created by tectonic plates "like a wound on the continent" describes the [Great Rift Valley](https://en.wikipedia.org/wiki/Great_Rift_Valley) in Africa. It is very much being made by tectonic plates.
[](https://i.stack.imgur.com/sP90u.jpg)
The Wikipedia article walks through how rifts like this eventually fill up with water and so a swamp would be halfway. The real Rift Valley is immense and has all kinds of things in it including other mountains, and of course like anything so big the highlands along the edge are heterogeneous and not all giant cliffs.
You could hybridize your rift with something like the Grand Canyon to get steeper walls. The Colorado has been working on the Grand Canyon for a long time but it is possible for a single catastrophic glacial melt event to carve deep channels in a very very short period of time. The Hudson is one of these. From <https://pubs.er.usgs.gov/publication/70030018>
>
> The valley and its distal deposits record a discrete flood event that
> carved 15-m high banks, formed a 120-km2 field of 3- to 6-m high
> bedforms, and deposited a subaqueous delta on the outer shelf. The HSV
> is inferred to have been carved initially by precipitation and
> meltwater runoff during the advance of the Laurentide Ice Sheet, and
> later by the drainage of early proglacial lakes through stable
> spillways. A flood resulting from the failure of the terminal moraine
> dam at the Narrows between Staten Island and Long Island, New York,
> allowed glacial lakes in the Hudson and Ontario basins to drain across
> the continental shelf. Water level changes in the Hudson River basin
> associated with the catastrophic drainage of glacial lakes Iroquois,
> Vermont, and Albany around 11,450 14C year BP (∼ 13,350 cal BP) may
> have precipitated dam failure at the Narrows... Based on bedform
> characteristics and fluvial morphology in the HSV, the maximum freshwater
> flux during the flood event is estimated to be ∼ 0.46 Sv for a duration of ∼ >80 days.
>
>
>
So: a rift like the Great African rift, and then a glacial melt event coursing down it to further carve out your steep cliffs that will help keep the dinosaurs down in there.
[](https://i.stack.imgur.com/wwuOO.jpg)
] |
[Question]
[
I'm really excited that this topic actually exists here. For the past weeks I've been thinking about creating my own fantasy world - because there are not quite enough yet. My primary aim is to make "magic" plausible. Thus, it has to be actually part of the laws of nature, which makes it less magic but compared to our world, it still counts.
Anyway. The basic concept is as follows:
There are six different strings: fire, water, air, earth, force, life. The four element strings make up all of the matter by being woven into each other, thus creating this world's types of "molecules".
Force strings will attract each other, thus allowing for gravitation.
As in our universe, each force will have its own mediators. Life strings will be necessary to allow plants and animals (people) to grow, have consciousness.
Some people have an additional organ, which allows them to manipulate one kind of string. This happens by creating a field which only affects one kind. For example. if you're a fire-weaver, you can exert influence on all fire strings in your surrounding area thus have the possibility to control fire. However you cannot create new strings, so water-weaving in the desert is significantly more difficult than on an ocean.
As stated, this is the basic concept, which I want to be fairly plausible before I go further into more details.
I'm looking forward to your feedback!
**UPDATE**
So in response to Zxyrra's answer (thank you very much for that! :) ), here are more details:
First of all the fantasy world inevitably has to differ from our worldview. I don't know if reality-check is even the right tag here.
**Physical characteristics**
As of now, I'd only say they're smaller than microscopically perceivable. To form matter, they are woven into each other. Depending on patterns and density, they form different substances with different properties.
Phaenomena / Differences between alike substances:
Generally speaking this depends on the purity of the element. Soil for example would have a high concentration of earth strings with minor impurities of the other elements. Sand on the other hand would have more impurities.
Also, the arrangement - or weave patters - are important.
F W F W F W F W
F W F W F W F W
has different properties than
F W F W F W F W
W F W F W F W F
though it consists of the exact same strings.
**Overlap/Energy-specifics:**
I think we have to abandon our present world view. The air element in my fantasy setting is not to be confused with the air on our planet (N, O, CO\_2,...).
Aggregation states could be borrowed. This allows water and other elements/substances to vaporize or freeze. Only substances with firestrings in it can burn. The higher the concentration, the more intense the fire and the easier it is to ignite (firing point at lower temperatures).
**Life Strings**
I'd simply postulate that it is possible :P Same goes for the manipulating organs. By carefully positoning resonaters, found in these organs, it is possible to create an elementary-field (as a result of interference of the single resonators) of almost any complexity , which affects the strings in the surrounding substances.
My question exactly is:
Are there any flaws, where this falls out of place, or is this somehow plausible?
[Answer]
## Edited based on question edits based on my previous answer
+1 for creativity and uniqueness, this sounds like an awesome idea.
I feel bad picking it apart now.
* **If fire represents flammability,** your matter probably won't change all that much from the presence of fire strings. "Flammable" water wouldn't need to suddenly turn into gasoline - maybe it would look slightly different or smell different, but in essence it would still be water. This is a problem because the distribution of fire strings in this scenario is unpredictable, and it means any given environment may or may not be flammable.
* **Life strings still should not work like that** There is no property or defining material that distinguishes living things from non-living. At the fundamental level, living things are just combinations of chemicals working together, changing, and reproducing. Adding strings of Life would have to cause extremely specific characteristic changes in surrounding strings and structure to cause all the traits of life. Furthermore, if strings capable of producing life as we know it **exactly** exist at all, why aren't some rocks alive? Or some parts of the air? Surely these strings exist in nature.
* **Organs, A)** While resonation is your best bet - you're on the right track - organs that operate on the atomic level, controlling specific objects, need precision unparalleled by any living organ to ever exist :P The evolution of an organ so precise is incredibly unlikely, past the point of "the least likely option happened" and nearing "this should not happen, ever".
* **Organs, B)** The evolution of an organ like this is extremely unlikely, precision aside. Organisms evolve complex and unique structures only if their bodies have the energy to maintain them. If we had the energy to evolve something cool during our evolutionary process - that is, we consumed more than we needed, so new organs would not starve - we would probably spend it on something simple and directly practical, such as a better brain, claws, faster running, etc. An organ like the one you are proposing would require a significant amount of energy before it became practical, which humans could not afford during evolution.
* **Physical characteristics of matter** will be wonky at the boundaries between substances. If water ends and soil begins, your water and Earth strings will have be cut - with overlapping ends, so as not to create a vacuum or lack of matter - leaving a transitional zone. **This would mean** all or many boundaries between substances would be poorly defined, and would cause a ton of problems in your world.
Don't get me wrong, I love your idea and there are ways to make it work. It's just challenging.
] |
[Question]
[
So, I'm ~~Darth Sidious~~ Supreme Chancellor Palpatine, and I've finally managed to ~~seize power~~ be democratically elected emperor for life. At last, I can bring peace to the galaxy! If only it weren't for those gosh darn rebels...
The worst part of it is, my generals keep sabotaging each other. They seem to think that making the others look bad, they'll seem better by comparison, and as a result nothing is getting done. I already made an example or two when I caught them at it, but that only seems to encourage them to be sneakier. What can I do to get them to help each other out instead?
--
**The setting** is an advanced civilization with a large population, and correspondingly large bureaucracy to keep everything running. Technology is futuristic looking, but not fundamentally different - just changes in style, e.g. there are still cars, but now they fly! There are still iphones, but now they're holographic! Society is ruled by a single tyrant, supported by his legions of doom, and an even larger number of clerks and administrators to keep everything running.
**The problem** is that promotion depends entirely on impressing your superiors, and it is a lot easier to be the least-worst option by pushing everyone else down, than it is to be the best on your own merits. As a result, the upper ranks are notably cutthroat, and asking your colleagues for help is a surefire way to torpedo your own career.
**The question** is, what can the autocratic tyrant do to encourage his minions and administrators to help each other out, instead of stabbing each other in the back?
[Answer]
Two philosophies will need to be built upon.
1. Make backstabbing more painful than cooperation; the path of least resistance
2. Positive reinforcement of cooperation, negative reinforcement of backstabbing
So we come up with the following trio of processes.
1. Promotion is a process of nomination and approval, involving both the direct superior and one's peers.
We're going to have the peer's views of you directly affect one's ability to be promoted. We can't make this a democracy, however (horror the thought!), so we'll need to allow workarounds in place.
Peers (Those that have the same superior, or report to those who have the same superior) can cast a silent nomination (or, alternately, cast a vote of no faith), or withdraw it at any time, with no need to explain or confirm. Nobody but themselves can view the status of the nomination; it's perfectly anonymous. This should drastically reduce gaining nomination votes by force but, alas, will not entirely remove it.
When at least 1/3 of peers have voted one way or another, and the vote tally is at 2/3 in favor of the nomination, *publicly* the individual is nominated for promotion. This nomination is immediately and automatically receded as soon as these qualifications are no longer met (people recend their votes, or more people vote 'no faith.')
Alternatively, the superior may nominate an individual and as long as at least 1/3 of the individual's peers who have voted have voted in favor of nomination (and not "no faith"), the individual is considered nominated.
Theoretically a superior can crack down on his organization until his candidate gets enough nominations, but doing so is very public, and will be exposed by point 3 (later on in this answer).
When an individual is nominated either upper command can review his or her work history and transfer/promote as needed, or the individual's superior's superior can relocate the individual within his/her organization as he/she sees fit.
Another alternative in place (as we can't depend on peers always to get our people in place!) is that a council that directly reports to the man-up-top (Looking at you, Chancellor) can review percentage of nominations of any member of your government, work history, etc, and promote anyone as they see fit, no nomination required. This is a fail safe to allow you to promote who you see fit, as well as to both make it seem less like a dictatorship, and to remove micromanagement for yourself.
2. Other incentives (pay grade, transfers, pardon of crimes) depends on work records, and anonymous, private peer recommendations.
Basically, if you impress your supervisor and your peers write good comments about you, you're more likely to get non-promotion benefits. Not everyone needs every reward being climbing to the top; sometimes a bump in pay or being transferred to that garden world is incentive enough. If the group you're inside is cutthroat, both pardons and transfers can help ease the situation, and this system would encourage people to play nice with others to get what they wanted.
3. Internal investigations
A separate branch of government is responsible for weeding out those who manipulate the system, who falsify reports of peers, and other such less-than-desirable behavior. This branch is also responsible for making problems 'disappear.'
*This* branch is overseen by a small team who reports to the aforementioned council. Since the council is overseen by you, and carefully formed by you, the quality of this system depends on the capabilities and loyalty of the council. That's on you, Palpatine.
...And there you go. We make it easier to use honey instead of vinegar, we slap the wrists of those who are cutthroat, pat the heads of those who get along, and weed out those who try to manipulate the workings. Naturally propaganda will be lathered on top, to hopefully create a culture of people simply *wanting* to abide by the rules you set in place.
Good luck, overlord!
[Answer]
Some sort of sliding scale taxation might work. Consider:
Each of your generals is making money somehow, either salary or their various black market dealings. Each of your generals has served you some number of days. Sort them as A, B, C, etc, so that A is your longest serving general. Set the tax rate based on how many days more General A has served you than General B. So A-B=... the larger the number "" is, the more their tax rate goes up. Now they have a reason to protect the general immediately their junior. Now, turn it into a graph...
A-B + A-C + A-D + A-E + etc =
The bigger gets, the more their tax rate goes up. Now they have a reason to protect everyone except the newest general. So, one more change -- if a general dies, he *stays in the equation*, but his number of days freezes, so once a general dies, everyone's rate starts creeping up -- every day, the diff gets a bit bigger. Now they have a reason to protect everyone in order to protect their own financial interests. Even if the death was legitimate, leave the general in the computations because that way no one tries to get sneaky and think they can get away with killing someone just by being crafty enough.
You can probably find similar "graph-like" incentives that will pull your generals together. Enough of them, and they'll actually think it is a good idea.
[Answer]
Maybe you shouldn't limit your example-making to "sabotage", so that being sneaky doesn't cut it. You need to call people out on not being helpful (literally, tell people when you notice). You need to emphasize loyalty, and how loyalty means putting success *first* not their own ambitions.
So, what if every time you have *any* of your generals' plans fail, you go over it and look for sabotage (of course), but also try to pick out one or two places where another general could have helped, but didn't (either helping when asked or outright offering help). A failure to help another general gets *noticed*, officially, when the failure of said plan is announced - maybe announced privately or publicly, depending on how you want to play it. Getting mentioned for failure to help counts against you. Do so three times, and there is a public warning (which could be a punishment, whatever you want). A failure to help that might have meant the original plan succeeded, gets a warning straight off. Three warnings and your general gets made an example of, exactly the same as for *sabotage* - for persistent little failures to cooperate, or for direct loss of three plans.
And, on the other side - failing to *ask* for help also gets noticed, and discouraged. Even in a successful plan, you can be asking how help might have expended less resources, taken less effort, gained more with the same plan or resources. Not asking for help where it could have bettered the plan gets the same official *notice* as not giving help, with a warning for three little misses, or for one miss that might have salvaged a failing plan - and treated as sabotage if persistent unwillingness to ask for help results in three warnings.
You will have to take a crash course in general-ing, to be able to catch some of those missed opportunities... or else you might be able to get your generals to call each other out - by using a consensus of all those *not involved* in the plan or in a position to help, since in the beginning they will have an incentive to hit both sides, and must defend their positions to each other (to get that consensus) *and* to your satisfaction. And once they realize that cooperation is being rewarded, and seeming too eager to point out others' flaws may count against them in this new environment, both among their peers and to their boss - their behavior should mellow over time until you hit a level you like. You can have "spot checks" for where other generals can help a plan at any point in its development, execution, or post-plan report (which should keep people thinking about it)... so it isn't easy for generals suddenly discover lack of helpfulness afterwards to sabotage others with, without giving a good reason why *they* didn't notice beforehand.
So, there's no safety in "sneakily" sabotaging their rivals - they can get called out for not helping when they could have, or for giving poor help or advice, or for not asking for help when they need it - and it will entirely depend on the boss's perception (said boss will want to look especially closely at *rivals* when judging 'not-helpfulness' to any general's plan). The generals want to be *seen* as having helped others, and to be *seen* as having asked for help (to avoid getting warnings for their own plans). Safety comes from fewer failed plans at all - especially if successes, or maybe specifically helping *another general's plan* to success, will reduce or cancel prior warnings. And this kind of behavior can be encouraged on successively lower levels - get your generals to encourage cooperation among those under them, and so on, until the entire organization is built that way.
Also, stop rewarding cutthroat behavior! Market it as *loyalty*, loyalty to your organization, your cause, and to *you*. Someone brings you info (about their peers, subordinates, superiors) that advances your organization or prevents a loss, they get rewarded. Someone brings you something that tears another down but is not *helpful* to your goals - they get neutral-to-outright-cool treatment, since minor squabbles or rule-breaking can distract from what your actual goals are. Play cutthroat behavior openly as selfishness and sabotage, noting that such a person puts themselves *above your goals* and that is neither behavior you want to reward, nor the type of person who should rise in your organization.
Make a special point of rewarding anyone, anyone who sets the goal above their ambitions - those who have asked for help, those who have sacrificed for your cause, those who are *loyal* to you. Pick out some names or instances of those lower down, so that your generals *know* what qualities impress you and catch your eye (and make sure no-one goes after your examples, please, the best loyalty is two-way). If you can get your hands on some names of those who "torpedoed" their careers by asking for help, bring them up (or create some) as examples to follow and heap their failures onto the heads of those who didn't help.
Really, you want people loyal to you *anyway*, so just make sure that letting plans or people fail is seen as deeply disloyal because those failures are *not helping*. This can also serve as a visible reason for your shakeup and new policies. Make sure your supervisors all the way down are looking for competence and *loyalty*, not competence and *ambition* (that's a combo likely to bite you, okay?).
[Answer]
First, consider the psychology of the dictator - that personality trusts no one, has to be first in everything, is extremely egotistical, paranoid and intolerant - especially of disloyalty. So impressing him would mean you're a totally loyal sycophant, but you'd have to be a useful one. Would a dictator encourage cooperation? Not really, that personality is too paranoid. Autocratic tyrant is a synonym for dictator so same applies.
A democratically elected leader, however would be another story. Since a hierarchical culture style is set from the top down, the leader would himself have to demonstrate the merits of cooperation, and then develop a reward system for those minions following his example.
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[Question]
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Isogamy: "sexual reproduction by the fusion of similar gametes." Not to be confused with Isogyny, "marriage between people of similar status or age."
All such species on Earth lack tissue-level organization, such as algae and fungi. What hurdles would an isogamous species need to overcome to achieve metabolism and organ systems comparable to animals without becoming anisogamous in the process?
EDIT: I may be wrong, but to me it seems the most obvious hurdle is how they decide who lays eggs or gives birth. Fungi conceive using mating bridges that produce fruiting bodies that release spores which grow into a mycelium. Obviously this is infeasible for non-sessile organisms.
[Answer]
There is no reason why such a species could not evolve. The main reason for anisogamy is that it provides the less-common gamete with the resources that the progeny will require for growth after fusion with a more-common gamete, minimising wastage of the parental investment.
Organ differentiation occurs in order to increase the efficiency of the various metabolic tasks the organism must undertake. The two criteria are not mutually exclusive.
In order to retain isogamy, the environment must support it. This means that internal fertilisation is probably out of the question, since that favours an anisogamous sessile egg/motile sperm arrangement. External fertilisation in water (like river or sea water) is also probably out of the question, as anisogamy has its advantages there too, in that the egg can carry resources for the developing organism while the sperm can be plentiful.
The most likely environment is one where there is an abundance of all the nutrients that the developing organism will need. In such an environment, the gametes may remain small and motile so that they can move around in an attempt to find an opposite gamete.
Of course, unless you want a system that strongly favours [autogamy](https://en.wikipedia.org/wiki/Reproduction#Autogamy), there will have to be a small degree of anisogamy, but only to the degree that gametes are only attracted to other gametes if they are of the opposite type (i.e. + vs -, to eliminate gender-biased labels), or able to distinguish between sibling and non-sibling gametes, though that would be much more complicated. However apart from that the gametes would be functionally identical.
Reproduction would most likely involve the parents each contributing to a pool of liquid nutrients in which a number of offspring could develop, before each inserting a similar number of gametes.
This does not preclude being functional in a liquid environment as opposed to a terrestrial environment. In any environment, this method of reproduction would require that the nutrients be isolated from the surrounding environment in order to prevent infection by foreign microorganisms and from being eaten by larger organisms - it *is* a packet of nutrients, after all.
The parents would most likely each contribute equally to building - or *being* the container for the nutrient soup, though the possibility exists that one parent would end up responsible for caring for the whole thing, or more likely that each parent would form their own nutrient pool and add their gametes to both their own and their partner's. Alternatively, both parents contribute to building a container, and finally add their gametes and then abandon it in as safe a place as they can find.
[Answer]
Both members of the mating pair would keep some of the fertilized ova.
This could arise quite naturally from organisms that evolved a mating bridge containing a number of spores instead of just the one. I can't think what the evolutionary advantage of this might be, but Nature is fecund.
If a line then evolved that attempted to keep using the mating bridge even in an environment where one or both parents was likely to be disturbed or moved, the creatures might develop the ability to produce viable progeny with a broken bridge. Some lines might even develop a physically weak spot in the bridge to control where it breaks and minimize the trauma.
Now, if at the same time the environment somehow imposed a significantly high metabolic cost of anisogamony, and this scaled into a high cost of sexual dimorphism in more complex species, you might see the dominant form of reproduction characterized by an exchange of genetic material followed immediately by an apportionment of the fertile mixture.
There would be no sexes as we know them. Each mating event would be characterized as 'fair' or 'unfair' depending on how evenly the spores, seeds, or ova were allocated to the parents. Divorce would be automatic.
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I'm building a world where a small subset of the population have the ability to induce rapid healing (potentially capable of sealing a large wound in seconds) by encouraging rapid cell growth. However, any fast healing has the potential of creating a long-term disease called "overgrowth", which is literally just cancer and has the same properties. The faster the healing, the greater the chances of overgrowth and the more severe the case will be.
There is no magic cure for overgrowth; further healing just makes it worse. It can be treated with focused *death* magic, but this has the same drawbacks as radiation therapy in our world (damaging to healthy cells, high potential for later recurrence).
What will be the effects of this form of rapid healing in medicine, warfare, and other aspects of society?
Other details about the setting:
This "magic" in this setting is relatively low-grade; it doesn't outright break the laws of physics and technically works by "communicating" with living cells and altering their behaviors and properties, sort of like genetic engineering on-the-fly. The energy/mass must come from somewhere, generally from food but many bio-mages can "cheat" by rapidly metabolizing nearby living organisms (like plants). Aside from the energy cost, there are no detrimental effects for the healer.
EDIT: To clarify further: Not all healing is dangerous; accelerating natural recovery in a clean hospital setting is virtually harmless. The faster the healing, the more severe the injury, or the more frequent the healing sessions, the more dangerous it becomes. Sealing an otherwise dangerous wound and allowing it to properly heal naturally is usually safe, but becomes more risky if it happens on a regular basis (sort of like x-rays). Completely healing a mortally wounded soldier in the course of combat so that they can continue fighting (as in, standard fantasy RPG healer practice) basically guarantees that they will die slowly and painfully over the next few years - but of course, an army that permits instant-healing soldiers is going to have a *major* advantage over non-healing ones. It's mainly intended to be a deconstruction of the "White Mage" style of combat support.
[Answer]
**Most people will fear and misunderstand healing magic.**
>
> Joe the farmer sits in his hospital bed. The healing required to fix a
> torn femoral artery is slight, and the risks of disease
> correspondingly so, but Joe lies in the bed, dying from blood loss,
> and refusing to let the white mage touch him. A local healer packs on
> more herbs and wraps the area in a honey-based poultice, and the mage
> has no choice but to look on, saddened by the knowledge that this sort
> of meaningless superstition will likely claim the farmer's life. *If
> only they would learn!*
>
>
>
A world with dangerous magic healing is a world in which magic healing will be misunderstood and feared by the majority of the people. Especially in a world like medival Europe, where most people are highly religious and illiterate, the common folk will at best view magical healing as something dangerous and deadly. At worst, they will view it as evil, unnatural, and a tool of the devil. Children with healing powers will be hidden or cast out. Alternately, they may be sent to strict military-run healing academies. For an army, little is of more value than a healer, and any tales of evil will quickly be forgotten by a commander looking to bolster the ranks of his troops.
**Healing will heighten the rift between nobility and commoners.**
Nobility, of course, will likely know a bit more about healing. In a medieval setting, the nobility are likely to be tightly linked with the military. Noblemen and knights will know of magical healing as being a useful and beneficial, if dangerous, asset on the battlefield. Magical healing will also likely be used without hesitation on useful guards, advisers, and servants who suffer grievous injuries. These are individuals that the local lord has more use for alive than dead, and they'll not be allowed to leave his service just because of some petty superstition or fear of an agonizing, protracted death.
Nobles will also likely know several white mages, and will probably learn from them more of the truth of the benefits and dangers of healing magic. A nobleman, knowing that minor, slow application of healing magic has little danger in it, will likely keep white mages on hand and prudently use their services.
Of course, in the eyes of the common man, this is akin to keeping priests to the Lord of Lies on hand to sacrifice goats for his dark blessing. Nobles who engage in healing magic will likely be viewed with more fear and hatred than most medieval lords otherwise would. Such unnatural continuance of life could well result in violence and revolution if the lord is not careful.
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**One scenario:**
The big war has grown way out of control, and several powers are desperately struggling to survive. Then:
Most of the soldiers are likely to die within weeks anyway, so quick fixing them to keep them alive to fight must be the major focus, with no consideration for the unlikely possibility that they survive the war.
**Conclusion:** Even more possibilities are available for a country fighting desperately in a war, meaning that a fight to last man standing scenario is more likely. People are not going to have good memories from that war.
**Another scenario:** (everyday life)
Living in a country with a decentralized population myself, I see one possibility for emergency treatment. Bad accidents could happen in pretty remote location, and if the wounds are serious enough, you do not have the time to transport them to the hospital. Time is a limiting factor.
Being a mage on the site, what can you do? Either let someone die for sure just now, or saving them at the risk of a probable future death. That choice is easy.
**Conclusion:** Whit limited medical equipment an the time running out, a mage is certainly better than nothing. Especially if the wounds would normally not be survivable.
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This healing method would be popular for:
1- Militants on suicide missions. You are going to die soon anyway, why not make as much of an impact as you can?
2- Patients in terminal stages of their sickness (not resulted from previous fast healing).
3- Adventurists and fanatics.
4- A means of first aid where immediate medical help is not readily available.
5- Scientists and doctors searching for quick, non-invasive methods of healing.
[Answer]
In cases where the patient would die otherwise from the wound, then absent considerations of cost to administer, it's a no-brainer -- alive now but dead prematurely later is still better than dead now. The interesting cases come where the damage is *severe but not life-threatening*, such as cases where absent this treatment people would face amputations, brain damage, and other significant losses of function.
In that situation, as today, some will say "save me from this at any cost" (or even "I'd rather die than live with this"), and some will accept living with an impairment in order to live longer and avoid the future pain from the overgrowth. Governments might become involved too, just as, today in the US, the government bars access to experimental drugs (because "experimental") even if patients would accept the risks. How much this happens in your society will depend on how strong social moral pressures are already; if the dominant religion holds fast-healing to be unnatural and not part of the divine plan, for instance, expect it to be barred. On the other hand, if your society is more utilitarian, allowing people to make their own choices more of the time, then this won't be a strong factor.
But, all that aside, there is an economic component. You said that the ability to administer fast-healing is rare, so that scarcity creates a demand. The military will set priorities for how those medics are deployed, with two competing goals: the medic is valuable, but his ability is most valuable in a "patch 'em up and send 'em back out quickly" meat-grinder where many soldiers are going to die anyway (so who cares about getting overgrowth?). In the rest of society, however, those medics can charge a price for their services so long as they don't saturate the market. If there's only one fast-healer in town, expect him to command a good price. This will mean that not all who would benefit from the service will be able to obtain it.
Finally, if the skill is very rare you can expect there to be pressure on those who are known to have it to use it. Some of those people might instead prefer to be software developers or pilots or teachers or musicians. What this means for people in this situation will depend on how they know they have it, when it manifests, how close-knit your society is, and how strong the sense of altruism is.
[Answer]
**Effects in medicine :** It will be a controversial healing method, something like suicide assessment in hospitals where you need to sign an agreement or a paper that you accept this healing method and that you are fully aware of its drawbacks on your health in the future. It's something the doctor can't decide, only the patient will choose whether to accept it or not.
**Effects in warfare :** Soldiers are expendables when it comes to winning a battle, so when a soldier falls in a fight he will be healed immediately using this method whether he liked it or not, of course this will enhance the chances of winning the war, but after many years the number of recruits will diminish because people will become afraid, not from death, but from painful death by cancer.
**Effects in society :** People will mostly riot against this healing method, since [many religions forbid suiciding](https://en.wikipedia.org/wiki/Religious_views_on_suicide), and this healing method is literally a suicide, so it will not be welcomed by everyone, and society will incriminate every mage who practices this sort of healing (talking about burning mages at the stake).
[Answer]
For *emergency treatment* the rapid healing can sace a life, and then the patient can move to an environment where the overgrowth is treated. For example if a major wound would be fatal, it is employed onnthe spot. Then the overgrowth may affect the same region treated, so it's surgically re-repaired to cut out the margins and sew up the old fashond way; or watched carefully for the imperfections which can turn benign and those are cut out.
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Gravity in our universe is an attractive force between bodies with mass [citation needed]. This allows matter to coalesce and form all the large scale structures we observe - planets, stars, galaxies, etc. At small scales, however, electromagnetic and nuclear interactions dominate the formation of matter (chemical bonds, quark-quark bonds etc.)
For the purposes of this question (and simplicity), we will ignore implications for the very early stages of a universe (first few seconds), where even with our friendly, attractive gravity our knowledge is somewhat shaky and repulsive gravity may very well have been a [real thing](https://en.wikipedia.org/wiki/Inflation_(cosmology)).
**Could a universe evolve with repulsive gravity?**
ie. The Gravitational constant has the same magnitude as in our universe, but regions of mass-energy repel each other, rather than attract.
Since 'evolve' is quite broad in this context, I'll narrow the the definition to some particular features. Some specific features of an evolving universe in rough order of necessity:
* **Existence** - It's no use if the universe spontaneously collapses early on and destroys itself in some way.
* **Transparency** - Being able to look around in this universe would be handy, preferably at (human) visible wavelength.
* **Stability** - Could local or global equilibria occur in this universe? Or would it exist in a state of perpetual high-energy chaos?
* **Any small scale structures** - Could atoms, molecules, crystals or rocks form? Could chemical reactions take place? How similar would they be to ours?
* **Any large scale structures** - A transparent universe is no use if there's nothing to look at!
* **Hospitable large scale structures** that some trans-dimensional traveler could visit and survive with reasonable life-support (ship, EVA suit).
* **Possibility to evolve life** - If large scale structure can form, could they harbor anything that we might call life?
On the face of it, it seems as though repulsive gravity would preclude the formation of of large scale structures like planets and inevitably lead to a Big-Rip scenario. However, the gravitational force is relatively [very weak](http://scienceworld.wolfram.com/physics/FundamentalForces.html), which could allow the formation of *something* in the first few million/billion years.
I realise I've asked about quite a few specific points, as I'd like as much insight as possible. However, general answers that look at the big picture are also appreciated!
Since this is a fair way outside the realms of theory and into the backwaters of speculation, I'm not looking for hard-science.
As a side note, presumably a universe could be designed with the other fundamental forces adjusted to allow for repulsive gravity. For the purposes of this question however, I'd like to keep the other forces fixed and change only gravitation.
**EDIT:**
FWIW, I threw together a very crude simulation with repulsive gravity and and short-range attraction to simulate chemical interactions (I said it was crude!). This revealed something quite interesting - If I made the system closed, initially the particles demonstrated something similar to [Brownian motion](https://en.wikipedia.org/wiki/Brownian_motion), but after leaving it running for a few minutes something strange occurred. Filaments of high-energy particles emerged with large spherical regions of relative calmness between them. The filaments almost looked like highways for the high-energy particles to move along.
Now, in all likelihood the simplifications I made for the simulation have rendered it completely unrepresentative of the universe I'm suggesting, especially if the universe expands indefinitely. However, I thought the structures that formed were worth mentioning.
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I guess atoms would still form (hydrogen, some helium, traces of lithium). However there won't be galaxies or stars, as it's exactly the attractive nature of the gravitation that creates that type of structure. And it's exactly because attractive gravitation does *not* lead to an equilibrium that we get stars: The gas collapses under its own weight until the nuclear fusion ignites and generates a pressure which counteracts gravitation and gives a temporary equilibrium (until the fusion fuel is spent). With repulsive gravitation, this doesn't happen; the gas will simply distribute equally in space, as any denser spot will be repulsive, thus reducing its own density.
Note that no stars also means no higher elements, so your universe will have no oxygen, no carbon, no nitrogen, no silicon … so no material to build planets of (not that they would form anyway, given the repulsive nature of your gravitation), and no material to form life from.
In short, your universe would be uniformly filled with hydrogen and helium, and little else.
Note that gravitation is unique in its all-attractive nature; all other forces tend to neutralize thanks to attraction of different charges and repulsion of equal ones. Thus if you remove attractivity of gravitation, all attractivity you are left with is through effective forces, more exactly, van der Waals forces.
Note that while van der Waals forces are attractive, they are not only weak, but also short range. So even if some structures (condensed hydrogen and/or helium) managed to form based on van der Waals forces, those structures cannot grow large, since otherwise the repulsive gravitation will win over. And due to the short-range nature of van der Waals forces, those structures could not develop any relevant pressure; definitely nothing that could cause fusion.
[Answer]
Ohkay. I had to answer this: because I think this will be a lot more fun than you think. I think this is going to get *messy*.
The reason that this is going to get messy is because this proposed universe won't have any stable states. If the big bang occurs the same way (with varying degrees of asymmetry), then particles are going to be flying everywhich way in an attempt to get away from each other. Sadly: They aren't going to be able to. Particles will repel particles. Some particles will be repelled away fast enough (thanks to the same principle that makes dust storms a problem) that they will hit other particles, leading to heavier elements (only up to iron, don't get excited) forming as the gravitational force is overcome by the nuclear forces (lets face it, they're just more buff). The entire universe is going to turn into a hot, messy soup of light elements.
The important thing to note here is that there is no incentive for these atoms to reach uniformity. If you imagine a set of perfectly repelling particles with any form of damping then they quickly hit an equilibrium state where they're all equally distant. Here there is no damping. There is no equilibrium.
Even in smaller clusters they're going to keep oscillating and flowing in chaotic patterns that have *no reason* to stop oscillating (like the hypothetical ball in a vaccuum tube running through the centre of the earth). Periodic structures will emerge as atoms get pushed into clusters, repel, and then get pushed back again. Rogue high energy alpha radiation will batter said periodic structures apart again. Matter near the edge of the universe gets *weird*, no matter what view you take on cosmology.
**EDIT to add a simple example**
Consider our pocket universe. It's tiny, and consists of three particles and one dimension. The particles are arranged along our dimension in the order A, B, C, where asymmetry is introduced by A being further away from B than C is from B.
At the start of the universe A and B are repelled by gravity outwards, where they run into either the edges of the universe (where weirdness happens) or each other's gravitational fields (if the universe wraps around). For now let's just assume they get 'stuck' at either end of the universe and don't move any more. Now particle B is in a situation where it's being repelled by both A and C with a slight asymmetry, and thus it moves back and forth between the two other particles. As it's in a vacuum there isn't anything to slow it down, so it will oscillate back and forth pretty much forever.
Using this model we can see that our three particle system can be modelled as an oscillator. But what if we only have two particles? If the universe is infinite, they just run away from each other. If it's finite, they hit the edges and get 'stuck'. If it wraps around then we can take one of our particles as a reference point, and show that it's the same situation as having the A, B, C arrangement, but A and C are the same particle! (You also have to worry about the gravity of your own particle in this situation, but don't worry, your pull both ways around the universe cancels out). That means that the simplest universe we can have that isn't trivial is an endless oscillator.
If you scale that up to more dimensions you get the universe described above. More than a little crazy.
**End example**
Eventually the universe might settle down (though it will take.. erm.. the age of the universe?) and there will be no more usable energy. An analogous state to the heat death of our own universe, and a somewhat sad end for what would otherwise be a ~~terrifying~~ fun place to exist.
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Even if the weak and strong nuclear and the electromagnetic forces are strong enough to avoid a "quark soup" state of the universe and reach to have atoms, the electrons on the atoms' orbit will repel each atom from each other, so now you have two repulsive forces.
Maybe you can manage to have little molecules due to ionic unions if your universe expands very slow or nothing at all, but forget all about having stellar structures (stars, planets, asteroids, comets...).
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[Question]
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According to google
>
> Although helium is the second most abundant element in the universe,
> most of it in the Earth's atmosphere bleeds off into space. Helium
> used for industrial purposes is a byproduct of natural gas production
>
>
>
and
>
> Helium is cryogenically distilled out of natural gas
>
>
>
I want my world (or at least some areas of it) to have good access to helium. My world has a level of technology roughly on a par with the Victorians, how could they acquire this helium? Can it be mined along with methane?
The gas does not need to be pure, any concentration which will give a good level of lift is acceptable.
[Answer]
[Wikipedia](http://en.wikipedia.org/wiki/Helium#Natural_abundance) suggests that natural gas is the only source that is potentially viable - it can contain up to 7% helium, along with methane and other gases. (The upper atmosphere has parts which are largely helium, but I doubt those are recoverable with Victorian tech...)
Extracting it will require fractional distillation to separate it from the other gases, which means cryogenics of some sort. The boiling point of methane at sea level is 111K/−161°C, which we can use as a rough target.
The Victorians did have access to early refrigeration systems - [the first vapor-compression refrigerator was built in 1834](http://en.wikipedia.org/wiki/Refrigeration#Refrigeration_research), and commercial versions started to show up a couple of decades later. Most of the early gas-liquefaction experiments use high pressures as well as low temperatures, which confuses things a little, but several gases with boiling points at roughly the right temperature had been successfully liquified by the turn of the century.
Assuming access to natural gas wells, then, we can conclude that Victorian tech would certainly have been able to produce helium on a laboratory scale, and it sounds like late-Victorian techniques would probably have been good enough to do so on a commercially-viable scale.
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I have a large capital city that is in the middle of a particularly large lake set in a standard low magic fantasy setting. In this city there is a agreement between three factions of were-creatures who run the criminal operations within the city. Werecats run the high end districts and activities, get involved in politics and bribes, fancy businesses. Werewolves run the brothels, protection rackets, act as fences and fight off the other gangs that try to operate in the area. Wererats pretty much run the smuggling and docks district. The gangs all have a number of non lycanthropes in them, but senior positions are all held by the lycanthropes, as well as a number of them at most levels of the gang.
Given that they want to keep their lycanthropy hidden, even from the rest of their gang (tongues wag and all that) don't know about the condition, what kind of contract and agreement would their leaders have drawn up/verbally agreed upon to keep it under wraps?
[Answer]
It depends on society's view of the creatures, their control over their wereishness, and how much the higher-ups know about each other.
Assuming the most likely situation, that society fears and hates them, that they totally lose it once a month, and they they more-or-less all know they are all werewolves, it become simply a game of self-preservation and MAD.
## Threats:
Losing control over yourself once a month, even if it's by turning in a fearsome beast, is a very vulnerable situation for somebody with lots of enemies, both within your organization and without. Seriously, it just takes ten guys armed with silver weapons.
Gangs, while always hated by everybody, normally operate more-or-less under-the-radar, and rarely are outright despised by the whole of society. If word gets out that the capital city is run by monsters hated by everybody, no matter how strong they are, they are eventually going to fall to the force of an enraged public.
Therefore, you'd have to keep this knowledge as concealed as possible from everybody, probably by threat of personal harm. It's easier if they have something to gain from you on a regular basis, so gang leaders would have to keep both whichever of their members and their 'property' who discover their secret convinced that it's in their best interest not to spill the beans and bring it all down. Of course, if they get too greedy, well, dead men don't talk.
## MAD:
The reason mutual assured destruction would set in is because the leaders of each gang know all the above. While they may try to kill and destroy each other, a stability would develop simply because they have an unstoppable weapon: knowledge that the other gang is full of wereanimals. Move too far or push too hard, and eventually somebody will drop the bomb, even if it destroys them as well.
Given the assumptions made at the top, there's no reason they'd ever want the word out, no matter how much the personal threat could help them. The information is just too dangerous.
[Answer]
Considering that criminal operations are often based on a certain level of violence (or at least a threat of violence) and on top of that lycanthropes are not known for their even tempers I would say it would have to be a very large threat. Letting non-lycanthropes know that they could be the next meal should they step out of line or wag their tongue could be very effective, start growling with glowing eyes when someone disagrees with you would be a strong case in your favor to winning an argument.
So knowledge of their existence has to be a very serious threat. Along the lines that some very serious groups of people would make a serious effort to wipe them out should they learn about them.
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[Question]
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The setting is Earth, millions of years in our future. In this setting a species of tree has made an evolutionary leap, allowing it to bypass the water transport constraints currently thought to be the primary limiting factor for tree height in extant species. This leap occurred roughly in our 'present day', so this new species of tree has had millions of years to refine and perfect this newfound ability, as well as allowing it to spread to new niches where it hadn't previously been able to compete. Spreading to new places will allow it to eventually colonize areas where near-ideal conditions exist (weather, water availability, nutrient availability, etc.), allowing it take full advantage of its new height reaching abilities.
The exact nature of this evolutionary change are a subject for a separate question.
For trees (in many, though not necessarily all, environments), genetically taller individuals are often evolutionarily selected for, since height means more access to light. Given that the previous water transport height limit is no longer a factor, genetically taller individuals in this new species, which already had better reproductive chances than their shorter neighbors, will be able to outcompete their neighbors much more significantly. This will provide evolutionary pressure to drive the new species toward taller and taller individuals. However, the new species is otherwise composed of the same stuff as it's evolutionary ancestor (other than the newfangled water transport imrpovement). For the purposes of this question, the change does not improve, nor detract from, the structural integrity of the rest of the tree's composition, except as new height/weight/leverage and similar considerations are involved, the wood itself is otherwise unchanged in this regard.
With this new freedom to reach new heights, and the time to do it, **how tall can a tree get?**
Obviously, I don't believe that removing that one limiting factor will suddenly allow trees to grow arbitrarily tall. Surely they will encounter some new limitation.
I conceived of this question from a 'square cube law' and 'structural integrity of living wood' perspective. My guess is that the next limiting factor they encounter will be related to structural integrity of the living material of which they are made. This could include things such as compression strength to hold it's own weight, or flexibility vs rigidity issues to flex in the wind without breaking now that much longer leverages are involved, or related issues.
However, I accept the possibility that 'structural integrity' may not be the next limiting factor, and welcome answers that identify and use some other limiting factor I hadn't considered. In that light, please assume that any changes to climate, atmosphere, sunlight intensity, gravity, and other environmental factors that are certain to change over the course of millions of years, have a negligible effect on this species, at least regarding its ability to reach record heights. Let's not get bogged down in "what else might change in that time?", and stick with "this one thing changed, so what's the new result?"
This part of the EDIT is to address concerns regarding lack of focus on the question:
My original wording of the question included this:
"While not strictly required, I suspect best answers will be based on a species that is currently one of the tallest species (redwoods, yellow meranti, mountain ash, coast Douglas-fir, etc). **How tall will this new species of tree be before it encounters that limiting factor, whatever it happens to be?** (bonus points for identifying the next limiting factor)"
This led to concerns about failing to identify a specific species of tree in my question. However, the question is about **what the new height limit would be** for trees in general, which is why I intentionally didn't specify an origin species. The original water transport limitation applies to all current species, and whatever factor produces the new height limit should, in theory, also apply to all species (though, like the current water transport limit, relatively few species would challenge that limit). The list of already very tall species was based on my assumption that these species were already challenging the current limit, and so are among the most likely to push past it, given the opportunity, and challenge the new limit.
Whatever that new limiting factor might be, some species will have a head start, so to speak, in achieving new record heights, since they will already have better form factors or strength characteristics that will be particularly suited to going beyond their current heights. Unfortunately, I don't know which species that might be (included in my list or not). Limiting the question to a single origin species will not necessarily yield the answer to the question **"How tall could 'trees' get?** in this scenario, unless I accidentally (miraculously?) stumbled on to the species that is already best suited to it on my own.
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Timber strength limit is about 100 MPa. Timber density when wet is about 1000 kg/m3. At 1m hight stress will be 0.01 MPa. Thus height limit is 10 000 m. This is assuming either no wind, or cube tree. Elongation 10, that is dia to height ratio, would limit max height to just about 1000 m. Giving half the mass to leaves to live will bring it down to 500 m. leaving some safety factor so that errors are allowed, branching is possible, wind resonance is tolerated, small earthquakes are ok... leaves 250 m or so.
Trees are actually pretty close to a limit of what they can be, as you start to account what they need to endure, and what competition leads to.
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To become structurally stronger than they would be by themselves, trees would likely 'lean' on each other for support, and would gain strength as they get larger and more intertwined. Of course, the lower levels would become compressed, and the ground the trees would be growing on would be themselves. The height of the tree now also depends on the philosophical question of whats tree and whats not, that is: is the tree under the ground part of the height of the tree above the ground, if the tree *is* the ground?.
However, the planet has limited resources, and could only produce so much wood.
The largest limiting factor for the trees now is carbon dioxide, which they would quickly run out of unless some other force were to release some large portions of it from the reservoirs of coal and oil in the ground(makes me think of algae blooms and dead fish...).
So they can only grow until they run out of source material.
But also more oxygen produced by the trees could create a more volatile atmosphere, which would result in more forest fires before they run out of carbon dioxide.
But whether these forest fires damage them depends on how thick the forest growth is, as the fire needs more fuel to spread, but larger trees would also(theoretically) be less likely to be damaged, because of their large size. Al the same time, their large size would mean certain death if the trees around them were to die, and would also mean any damage done to their roots would be that much more deadly.
But if there are larger forest fires in one part of the globe, then that means more CO2 in another, perhaps rain-forests, and therefore taller trees there. Which means the limit of CO2 can not be applied to the entirety of the trees, as some trees would get more CO2 than others, the others being dead, releasing the CO2 for these other trees, in other areas potentially not affected by CO2.
To know exactly how tall the tree can be depends and these factors and more. If you have the time you will be able to make a computer model and get an approximation. That's how a lot of information is gotten for such things anyways.
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<https://en.wikipedia.org/wiki/Sequoioideae>
According to Wikipedia, is a subfamily of coniferous,..
The largest current trees on Terra,
[]
so regarding ideas from comments, to build a very large wood structure/building , you first have to have the further conditions:
1. Genetic modified tree seeds, ex( recent developments of energy trees grow in 4 years at 16 + meters.) ->
<https://en.wikipedia.org/wiki/Energy_crop>
2. human attended growth and tree spacing calculations for the trees growth perspectives/expectations
3. due to recent wood technologies you could build very big wood segments from multiple smaller glued wood segments.
4. so I think that its not feasible to wait 200 years for a tree to grow to a dizzying height ..
5. soo its more feasible to grow a forest with your required technical specifications tree, that in 10 years will grow desired specimens , from which .. :)) go to point 3..
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[Question]
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**Background:**
My SciFi books are set 50-100 years into the future.
My combat ships use fusion for power and direct thrust. (See previous question: "[Performance envelope characteristics for a hard-sci-fi torch-ship](https://worldbuilding.stackexchange.com/questions/181093/performance-envelope-characteristics-for-a-hard-sci-fi-torch-ship)")
As many helpful people pointed out, one of the main issues with high power will be heat.
My ships are able to control, with a high degree of precision, plasma envelopes surrounding them. This is used in-atmosphere for magnetohydrodynamic propulsion. In space, the plasma-envelope is used for stealth by absorbing/reflecting radiation from radar etc.
**My question:**
If the ships have flakes of metal suspended in the plasma (something like: [dusty plasmas](https://www.intechopen.com/books/progress-in-fine-particle-plasmas/dusty-plasmas-in-supercritical-carbon-dioxide)) the flakes will absorb heat from the plasma and radiate it. If the flakes are mirrored on one face and black on the other and if the ship can control the orientation of the flake, is this a valid mechanism for preferentially radiating heat in a desired direction?
Many thanks in advance! I am happy to share more info!
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# It might work, but..
Your concept requires several unknown/unresearched aspects to behave correctly.
IF you can get a way for those mirror/nonmirror flakes to orient correctly, AND have them circulate correctly to collect the heat in the first place without clogging, AND have them carry enough heat AND have them not absorb too much heat from your plasma turning it into gas (which would then just float away), then the concept could work. I have no idea how you would orient the flakes other than along the magnetic lines though. You would be able to select IN or OUT, but not any other direction.
If your primary concern is for the cooling effect, then consider this:
There are similar concepts for space heat rejection that require a lot less hoops be jumped through to work, and would be just as spectacular for storytelling purposes.
Take a look at this link: <http://toughsf.blogspot.com/2017/07/all-radiators.html>
This is a webpage that devotes itself to all thing space coolant, both current, planned and theoretical.
Specifically, look at the Curie Fountain Radiator.
It is very similar to your idea, but requires a lot less finicky tech to be made to work.
[](https://i.stack.imgur.com/l5xnb.jpg)
quote from the page, just incase it gets lost:
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> A Curie point radiator operates around the temperature at which metallic dust particles lose their magnetism. Iron, for example, loses its ferromagnetism at 1043K.
> The Curie point radiator uses metal filings or even liquid droplets. It is heated to above the curie point temperature and ejected into space, away from the spacecraft. A magnetic field is in place, but they are not affected by it. Iron can be released at temperatures of up to 3134K and collected at 1043K, but Cobalt has a Curie temperature as high as 1388K, is naturally black and boilds at 3400K, making it a better coolant. The small size of the particles or liquid droplets allows several megawatts of waste heat to be radiated away per square meters.
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I see some problems with the concept as it stands now:
* Plasma can be depicted as a very hot gas, where atoms are dissociated. One usually needs RF frequency to sustain the plasma. I suspect those metal flakes won't do nice things while interacting with the RF radiation.
* Assuming the RF radiation doesn't mess up with the flakes, they won't be aligned where you want them to point, but where the electromagnetic field configuration decide to align them, and it won't be a stationary configuration (remember, you need a RF frequency to sustain the plasma)
* If the flakes emit more on one side than the other, they might be subjected to a force asymmetry as a consequence they would move, which again is something you don't want, because you want to point them in a specific direction, most likely away from your ship.
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[Question]
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My dragon is not large in size (around the size of a house cat), flightless, and doesn't shoot fire from its mouth, much like in popular culture, but it shoots from its **rear**. I think it's much safer that it shoots from its butt than from its mouth.
Something like this:
[](https://i.stack.imgur.com/x1ZGi.jpg)
This dragon doesn't use gas (which is kind of impossible to store), but uses liquid instead.
It's a mix between a skunk (can shoot at its attackers accurately and is able to squirt 5-6 times) and a bombadier beetle (which uses two compounds). It only uses this when threatened.
It has 2 type of glands: one stores a flammable oil (which every organism has, I would say something like the spiny-tailed gecko shoots) and the other stores a pyrophoric organic fluid (ignites in air on contact). Something like [this video](https://www.youtube.com/watch?v=EmkBH-ncG1Y).
So my question is:
* **Can this be biologically plausible?**
* **If so, what type of pyrophoric organic liquid can my dragon be able to store and synthesize (i.e. it can create this pyrophoric liquid and store it without it reacting with oxygen)?**
* **What about what about Triethylaluminium or Diethylzinc, can it can able to store or synthesize them?**
I'm looking for a simple answer: either "no, it's not possible to store a pyrophoric liquid", or "yes, this is the compound it can store".
[Answer]
The [bombardier beetle](https://en.wikipedia.org/wiki/Bombardier_beetle) is notorious for being able to spray aggressive chemicals on whoever happens to annoy it.
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> The spray is produced from a reaction between two chemical compounds, hydroquinone and hydrogen peroxide, which are stored in two reservoirs in the beetle's abdomen. When the aqueous solution of hydroquinones and hydrogen peroxide reaches the vestibule, catalysts facilitate the decomposition of the hydrogen peroxide and the oxidation of the hydroquinone. Heat from the reaction brings the mixture to near the boiling point of water and produces gas that drives the ejection. The damage caused can be fatal to attacking insects. Some bombardier beetles can direct the spray in a wide range of directions.
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And for setting up a fire, you don't need a pyrophoric liquid. There are organisms which can produce electricity like the electric eel, thus if you can trigger a small spark while you are spraying your liquid, voila, you have your rear firing dragon.
Triggering a spark on short distances is less cumbersome than projecting it at longer distances.
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[Question]
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Our philosophy is based on the concept of energy as a positive, because we generally live on a planet in a low energy state which does work via fuel. As such, we don’t really have articulate language for “absence of energy.”
However, in electronics, we originally conceived of the absence of charged particles as being a positive. Today it is called “hole flow” and we still refer to the part of a battery that is missing charge carriers (electrons) as the “positive terminal” with the “higher potential”, and it is the “cathode” (which is Greek for “the way down”). Even in electronics schematics we draw semiconductors such as diodes and transistors with arrows pointing in the wrong direction - opposite of the direction that electrons physically move. Of course this was done because at the time we hadn’t understood how electricity really worked. But in the end, it’s just words and it all works out the same.
So I am conceiving a world with an over abundance of energy, where the physics is the same, but instead of adding fuel to increase energy, they typically add an anti-fuel which removes energy to do work. Anything which removes energy is valuable here, because it is how they make light, power transportation, run machinery, etc.
Basically, their thermodynamics language is the equivalent of hole flow in electricity.
An example phrase in our philosophy might be “If you have put a hot bottle on your feet, your feet are warming up.” If we look at the contrapositive, it has many negations making it very wordy and cumbersome: “if your feet are not warming up, you have not put a hot bottle on them.” To make this less cumbersome in their daily conversations, I need cold-based language, as cold-energy naturally flows from colder to their ambient hotter environment via what we would call endothermic reactions. To them, “fuel” would be anything which creates cold And causes it to flow out. Yet, fuel is obviously the wrong word for that. In their language, the statement above may be like this: “If your feet remain cold, you did not use a coldless bottle.” Or would it be “uncooled” or “defrigerated”?
See the challenge is that our language treats heat and energy as the positive, like electron flow. Referring to cold and energy deficiency as a positive is unnatural to us.
So the question is to state the fundamental laws of thermodynamics in their contrapositive statements, which are logically equivalent, and then try to prune out all the cumbersome negatives to form an articulate phrase. I will likely be deriving words like “defrigerate” For heating up or “excool” for inflaming (not the greatest analogy). The results do not use the words “heat” or “hot” or anything defined with those concepts such as enthalpy. As a side, thermometer scales are likely inverted as they measure cold content, so temperatures $decrease$ with heat. So their math changes a little - ideal gas law becomes PV=-nRT, for example, and all units of measure would be different (but they would still work).
**EXAMPLE**
Start with the First Law of Thermodynamics as written:
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> Heat is a form of energy, therefore heat energy can’t be created; can not be destroyed; it can be transferred to a new location; and can be converted between different forms.
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**IN CONTRAPOSITION, these logical equivalents are true:**
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> If heat energy can be destroyed, then heat is not a form of energy.
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> If heat can not be transferred to a new location, then heat is not a form of energy.
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> If heat can not be converted between forms, heat is not a form of energy.
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Because adding coldness is simply the removal of heat from a system, adding coldness obeys the exact same laws of thermodynamics. Cooling is simply a name given for the transfer of heat *outward* into the ambient environment. Coldness is the quantity of energy deficiency which occupies the areas of a system in the places where energy has left it. When cold is added to a system, the ambient environment must increase in heat (loose coldness).
So the following laws must also be true:
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> If coldness can not be transferred to a new location, then coldness is not a form of energy.
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> If coldness can not be converted between forms, coldness is not a form of energy.
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This is an example of the framework I am trying to create for a cold-based thermodynamic philosophy.
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As far as I understand, the question asks the community to invent a new vocabulary of physical quantities, which are just our plain old physical quantities with their signs changed.
$$\begin{array}{l|l}\text{Positive quantity}&\text{Negative quantity}\\\hline
\text{Work}&\text{Repose}\\
\text{Energy}&\text{Lethargy}\\
\text{Potential energy}&\text{Static lethargy}\\
\text{Kinetic energy}&\text{Dynamic lethargy}\\
\text{Internal energy}&\text{Intrinsic lethargy}\\
\text{Thermal energy (= Heat)}&\text{Coolness}\\
\text{Power}&\text{Weariness}\\
\text{Temperature}&\text{Coldness}^1\\
\text{Potential barrier}&\text{Lethargic chasm}\\
\end {array}$$
¹) Note that their coldness is minus 1 over our temperature, so that their coldness approaches zero from below when our temperature goes to plus infinity, and it goes to minus infinity when our temperature approaches zero. Not to be confused with *our* [coldness](https://en.wikipedia.org/wiki/Thermodynamic_beta) $\beta = 1\,/\,k\_{\mathrm{B}}T$.
* In their mechanics, repose equals minus force times displacement. Repose divided by time is weariness, the negative of power.
* In their electrotechnics, a current flowing through a resistor produces a coolness equal to minus the square of the current times the resistance.
* In their thermodynamics, coolness flows from low coldness to high coldness.
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I don't see this as a linguistic problem because the words for these states would develop naturally. The nurbdingle on your floop makes it spunge. The problem is in translation so your readers can understand it, and the translation must include an energy positive metaphor to articulate your concept - without a context the reader is going to get lost anyway, so you might as well stick with spunging floops.
Context and communication are the real issues you need to work around, so why not just use words we're familiar with to explain it - dampeners, nullifiers, shields, taps, drains, holes, sinks, capacitors. Batteries would absorb charge until they were full then need to be discharged before they could be used again, but we'd still understand them (and they would still function, in a practical sense, almost exactly) as batteries.
I suggest thinking in terms of practical use of the language instead of trying to explain the details of grammar we have no equivalencies for. These kinds of concepts and thoughts can be communicated without a language barrier.
As a complete aside I think a bigger problem will be the inversion of entropic law, or articulating entropic law in an inverse philosophy.
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[Question]
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So I have an idea for a biome in which avian humanoids are the dominant intelligent lifeform. They live inside of trees that dwarf the redwoods of our world. The trees grow so tall and so thick (akin to a skyscraper) that they petrify from the inside out as they grow, forming a stony core a few meters from the surface. This stony core is obviously structurally weight-bearing, which begs the notion of the viability of boring through it to form cities inside of these gargantuan trees.
I would like to know the feasibility of trees that adapt like this and the way that they would support their own weight. What I would also like to know is what would the process look like for a tree to petrify itself from the inside out, as an adaptation for growing larger to out-compete other species for reaching sunlight.
These trees would, to my mind, be in the realm of 1000-1500 meters in height or larger, with considerably thick cross-sections (a tenth or more of their height at the midsection, a fifth at the base). I know not whether this is an appropriate dimension for these mountainous trees. I'm not sure about deciduous or coniferous yet either.
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**Minerals:**
For a tree to deposit a stone core, all you need is minerals to be present in your environment in such quantity that they can be treated like a waste product. Look to coral, or sea shells, and imagine a plant depositing the same stuff. Fossilization can take very long or almost no time at all, if the appropriate dissolved minerals are present in the water.
I imagine trees eating away at limestone deposits, then depositing the carbonates in structural columns inside the tree. The stuff might be effectively a waste product, but a useful one. The tree is essentially filling the inside space with lime deposits, and protecting the lime deposits with the outside of the tree. The tree could be reclaiming the wood it laid down and replacing the lost structural material with what is essentially limestone.
This is an easy stone to work, very porous, and the tree may even leave natural cavities in the structure. This could aid in ease of tunneling. Limestone is used as a building material and ingredient in cement. As long as the outside of the trunk is alive, the inside is protected. The minerals soaking down would likely cause interesting deposits in caves people made, giving it a very organic feel. I've even seen basements in limestone that were growing crystal-like structures and had opalescent deposits.
The ability to transport materials is often the limiting factor on how high your trees can get. If you can have a natural way to pump the material up, though, the sky is literally the limit. How do geysers sound? These have (admittedly dangerously) hot, mineral-soaked water under pressure that the tree could direct upward in narrow tubes to fill a pool at the top. The water and minerals are soaked downward to make the tree and supply needed water and minerals (as well as the structural minerals for your exotic growth). The trees that grow near geysers become enormous, while the trees simply drawing on water in deep limestone deposits are "merely" huge. There could even be different varieties, and people carry geyser-type plants to geologically active areas and spread the species.
That gives you giant trees, symbiosis between man and tree, and geysers (what story isn't better with hot running water?) There could be a lot of different complications with this design that need to be hammered out, but unless someone has a huge and obvious objection, I think this could be a viable route for you.
[Answer]
The core of the tree self opalizes.
[Wood opal](https://en.m.wikipedia.org/wiki/Wood_opal) is a real thing. It is a type of petrafied wood. Opal is a hydrated amorphous form of silica.
I have read about artificial opals being made with sodium silicate. A soluble compund of silicon.
So for your trees they need the roots to produce Sodium Hydroxide which will dissolve silica in the rocks. Then the tree transports the Sodium Silicate to the heartwood, where the tree then using a Chlorine pump (like how your stomach makes hydrochloric acid) causes silica to precipitate out, opalizing the wood.
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[Question]
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I, Marie Leaveau, am an alternative voodoo occultist entrepreneur from Louisiana and run an underground black market called Grimm Fairy artifacts Inc. Dubbed "The Bitch Queen" by naysayers, I have been operating since the 1800s, offering my services to a wealthy clientele in the application of witchcraft. For all the whiny millennial snowflakes who say that the American Dream is dead, I am a prime example that this is incorrect, as I have made a sizable profit and work to expand my business in the 21st century.
My business offers several services:
1. Harvesting materials from slaves (fat, bones, skin, etc) to create magical artifacts. These items are imbued with the Mana of the individual they are made of to create magical effects. These can include items used to ward off mystical creatures, to creating better weapons, to something mundane like a wallet that can hold unlimited amounts of things.
2. Sacrificing individuals in occultic rituals. They Mana harnessed from these sacrifices are used to power spells. Alternatively, specific organs can be harvested for use as necessary ingredients for other rituals.
3. Voodoo rituals that affect targets have a backlash on the user. These individuals are used as proxies to absorb the negative energies resulting from the backlash, absorbing the negative effects.
My ultimate goal is to become the Walmart of the black market, a one-stop shop for magical items or services for rich clientele. Of course, this will be a massive operation involving many parts, from paying slave-nappers to obtain targets from third-world countries and failed states, to transporting them to various locations around the country, to housing and storing them until an order is placed, to actually performing the ritual when needed. My organization has been hampered by the abolition of slavery, and new technology has made operating more difficult.
I need a way to streamline this operation while ensuring that all it's moving parts operate seamlessly, while also cutting costs to return as much profit as possible. How can I make this work effectively?
[Answer]
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> Walmart of the black market, a one-stop shop for magical items or services for rich clientele
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**Walmart is not known for its rich clientele. It's known for offering extremely cheap goods in a basic, no-frills store staffed by low-wage wage workers, and long check-out lines.**
Being Wal-Mart is theoretically easy. Only deal with large suppliers and in large volumes, don't pay employees much and don't put the store in a high-rent area. Create a private label for goods that haven't passed other's quality inspections, and buy in bulk.
One important concept is WalMart isn't generally known for making anything, they're known for selling it cheap. Most of the things at WalMart are other brands sold at the lowest possible price. **You don't need to worry about how goods are produced, you need to worry about getting as many goods as possible, and marking them up as little as possible.**
**I believe what you want is to facilitate illegal transactions like silk road. Be a broker for these illegal activities and connect buyers with sellers - and get your cut!**
Hexes are illegal to buy and sell. The answer - buy and sell raw materials for illegal hexes in your chain of high-end boutiques! Use your existing legal network of stores to ship small quantities of high-end illegal product. Much like [Gus Fring's](https://breakingbad.fandom.com/wiki/Gustavo_Fring) used a legal storefront to ship meth around, you use your chain of boutiques.
As for high-end illegal hex services, just hire the "right" people. Many drug dealers work at bars and restaurants and use their legit job to launder their drug money. Same for your "hexers" - they launder the money through your organization, and you get a cut! Good thing your prices are sky high!
As for folks to be proxies for bad luck and other spell blow-back, you've got that solved too. The charitable arm of your organization is great at finding folks who will die soon from aggressive disease and arranging large payouts to families. All it takes is a wink, nod, and a lock of hair. Some CEO gets hexed in New York and a Piano falls on someone in L.A. - best of all, it's tax-deductible!
[Answer]
# Marketing research, Venture Capital, and aggressive lobbying
**1. Marketing research**
You're assuming that there's a large market just waiting for you to take control. You need to think carefully about how big the market really is. You want to become the "one-stop shop for magical items or services for rich clientele." How many rich people are looking for these kings of magic services? How many of them are willing to stop using their current provider and start working with you instead? And how much do they spend every year on these services? How much of the business could you get? You use Walmart as your example. Walmart doesn't actually have a majority of the market share in groceries or apparel or a number of other markets in which it competes. But those markets are so big that they can generate massive revenue from non-monopoly market shares. A lot of name brands are in similar positions. Your market might be so small that you'll have to absolutely dominate it in order to achieve the level you're envision.
**2. Venture capital**
Scaling your business is going to require a lot of money. You need to find people and organizations who can bankroll your expansion until you achieve profitability at scale. [Here's](https://www.growwire.com/how-to-get-vc-funding) a quick guide to getting venture capital money and the Small Business Administration has a guide to writing a [business plan](https://www.sba.gov/business-guide/plan-your-business/write-your-business-plan) (a must for getting funding). If you want more background, I recommend [Investment Banking](https://www.goodreads.com/book/show/6455493-investment-banking) by Rosenbaum and Pearl. One advantage of getting outside funding is that the investor might help you run your business more efficiently.
**3. Aggressive lobbying**
It sounds like you're planning to break a lot of laws across several countries. So you're going to need a serious lobbying machine. Put aside a good chunk of your revenue for lobbying in every country where you operate.
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The Nazis during WWII had to find a way to industrialize human extermination to fulfill their sick dream of racial purity via the concentration camps.
Their approach can be the baseline for your streamlined process.
Add maybe something taken from the modern slaughtering industry to reduce the human intervention in the entire process.
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So 1800's... trying to catch up to a 20th century business model.
These days it is time to go with synthetic voodoo products.
Start at the digital an molecular level and instead of dealing with creatures that have feelings and emotions and all that messy stuff, get a few PCR machines some stainless steel vats and couple of un-employed recent bio-mages phds that can't find a job. Set them up with a few bio-reactors and get them cultivating a few strains of e-coli to pump out some designer-hex-molecules. Its purer, more potent, and the authorities policies can't keep up with the tech. No law against it.
Most towns welcome, a "craft" brewery.... no need to tell them what is going on in the back.
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**Import**
Just like Walmart buys from China, bring the product in from overseas.
Plenty of places where you could set up shop that people just go missing and nobody cares. Bring the items into the country as the finished product ready for sale. Customs are looking for drugs and illegal products. Handmade leather wallets would get pass all inspections. Body parts come in as "Dog Treats" in heat treated, vacuum sealed bags. Potions as perfumes etc.
Since it contains nothing illicit and all the proper import paperwork filed, nobody would be any wiser.
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All that worked well enough when slavery was the case. Fortunately, due to your wealth, longevity, and insight, you started acquiring connections worldwide to use prisoners.
Cambodia was pure gold for you. Turkish prisons were a steady standby and provided a consistent stream. Saddam was good for 30 years but, you know, things change and the incoming regime was too religious and too bent on revenge instead of a mutually beneficial relationship.
Now, China is really a good chunk of your business and with the Uighurs and soon Hong Kong, you're really hitting your stride.
] |
[Question]
[
This is a submission for the [Anatomically Correct Series](https://worldbuilding.meta.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798])
Giant seahorses are often portrayed in fiction as being ridden by merfolk or other underwater people.
[](https://i.stack.imgur.com/BsraC.png)
I'm wondering if such a creature would be biologically possible. I"m aware that simply increasing an animal's size isn't that simple (given the square-cube law), but is there any way for giant seahorses to exist?
[Answer]
## Enlarged Marine Animals need a reason to be large
I believe large seahorses are more than possible. Anatomically, seahorses are simply fish, they have no relation to horses let alone any mammal or land animal.
As they are simply fish, we have seen enlarged fish and sharks to enormous scales - the largest currently being the Whale Shark:
[](https://i.stack.imgur.com/HRiLy.jpg)
You seahorse does not need to be this big though, so perhaps just a sunfish size is adequate as follows:
[](https://i.stack.imgur.com/czG3E.png)
So given we have examples, we know it would be possible.
Now for evolutionary pressures: there is likely a reason why Seahorses haven't grown to this size yet. That's because **larger animals need much more food** to sustain themselves, and much more vulnerable to ecological and environmental change. Larger animals tend to have to travel further, to abundant 'small filter food' areas that have a seasonal variation, so the size becomes an advantage as you can support longer endurance-style swims in comparison to smaller fish.
So your seahorse will need to **eat lots, swim far, and likely be a filter feeder**.
Unfortunately, **sea horses are not efficient swimmers** - in fact they are the slowest fish in the world. This is because they are vertical, and use their dorsal fins for propelling, in lieu of their tails. That makes sense though and is ok, as the appeal of being a sea horse is being sexy amongst the safe coral, not in long endurance swimming.
So if it does happen, **to be large your sea horse may actually start looking like a normal fish** instead.
[Answer]
A giant seahorse could exist in a seahorse-like shape if there were something like trees underwater, with the seahorse being like a large chameleon but without legs
] |
[Question]
[
In FTL-free universes, interstellar travel is often done by vessels capable of continuous acceleration (the drives themselves are often magitech), which can use the effects of relativistic time dilation to "shorten" travel times. However, while we often talk about the vacuum of space, space isn't a true vacuum. The [interstellar medium](https://en.m.wikipedia.org/wiki/Interstellar_medium) isn't a perfect vacuum, per $cm^3$ between $10^6$ and $0.0001$ particles can be found. Crashing into anything, even ionised hydrogen gas, at velocities above $0.9c$ is a very bad idea. The kinetic energy of relativistic objects is given by [this formula](https://www.vcalc.com/equation/?uuid=85b315c3-baf3-11e3-9cd9-bc764e2038f2).
$$E\_k=\frac{mc^2}{\sqrt{1-\frac{v^2}{c^2}}}-mc^2$$
This tells me that a spacecraft with a cross-section of $50 m \* 50 m$ moving through dense interstellar medium ($10^6$ particles per $cm^2$) and average interstellar medium ($0.5$ particles per $cm^2$) at $0.9c$ will have to deal with $2.6\*10^{14} J/s$ and $6.5\*10^7 J/s$ respectively. For comparison, this is about the energy of a $100 kt$ nuclear bomb or a $9 kg$ TNT demolition charge each second respectively. To say that this is bad is an understatement.
Some sci-fi authors have suggested using ice as a shielding to deal with this, but running the numbers shows that this is a ridiculous proposition. Assuming that:
* the sublimation of ice in a vacuum can be viewed as an isobaric process;
* all of the collision energy is absorbed by the ice at 100% efficiency and used to heat it;
* the ice will, according to phase diagrams, sublimate at $213 K$ or $-60 C$;
* the ice is at $5 K$, to begin with; and
* its heat capacity in this temperature range is roughly $4000 J/kg\*K$
We'd need about $25\*10^9 kg$ of ice for a 10-year voyage at $0.9c$ and for the same voyage at $0.99c$ we'd even need $110\*10^9 kg$ of ice. For anyone who wonders, this would be a 10 and 44 km stack of ice respectively. This wouldn't be a spacecraft anymore. It would be an interstellar comet. The "strap your spacecraft to an icy Kuiper belt object and fly to the next solar system" idea sounds interesting but it isn't what I'm looking for.
**The Solution Are Energy Shields**
While energy shields are pretty much considered to be the antithesis to hard-SciFi, they aren't that fictional. Most of the gas out there is already ionised, and the non-ionised part can be ionised using UV lasers. Rocks and dust grains are vaporised by a point-defense grid before the vapor is ionized as well. The spacecraft itself is covered in superconducting magnets, whose fields deflect the ionised gas away before it hits the spacecraft.
Design-wise I think this would result in kilometre-long spindles, which are thickest at the midpoint. During the acceleration phase, the spindle will plunge through the interstellar medium like an energy dagger. The deceleration phase is slightly more complicated, as the engine would be at the front. I don't think this will be a problem however since an engine capable of continuous multi-gee acceleration will have no problem punching through the interstellar medium. The rest of the vessel is now protected by the magnetic shield and point defense on the lower decks.
**Are my assumptions about the damage the interstellar medium will deal with relativistic spacecraft correct? Did I mess up my calculations? Is my idea for dealing with this any good?**
[Answer]
I think, you are not getting it right. It's better to look at situation as spaceship is staying in place and hydrogen is coming for it at relativistic speed.
From this point of view your ship practicaly under bombardment by proton beams, like from particle accelerator. 0,9c is not that big number - it's only GeVs. We do not need extreamly large accelerator to achive this energy, and we already deflecting such proton beams with magnetic fields in relativly small installations : about tenth of meters and tens to hundres of tons. You don't even need to spend energy for it, if you ar using superconductros (energy goes from spaceship moment reduction - i.e. from your engine)
So yes, magnitic shielding is a good way to reduce corrosion and induced radioactivity of spaceship.
And you shouldn't be vary much about structural integrity: while energy of this proton beams is high, there total impulse is very small. They will not push spaceship with much force. So its more like very bright light (i.e. from nucler explosion), then stream of gas.
[Answer]
I think your math may have seemed overly daunting because you need to consider that you are spreading the force out across your 25 million cm^2 surface area.
**To expand on Failus's answer:**
The most dangerous speed will be about 0.6c. At this speed, your hull is impacting about 18 billion atoms = 3.29e-17 kg of of hydrogen/s **/cm^2**
At 0.6c you are looking at 1.62E+16 J/kg of hydrogen meaning your actual resistance tops out at about 0.1 J/cm^2 in a normal vacuum or 100 J/cm^2 in dense space which is well within the tolerance for many materials. For comparison, a passenger airplane moving at 250m/s in Earth's atmosphere experiences about 0.9 J/cm^2. So, as long as you avoid any thick nebulas, your hull should be just fine as long as you have a basic method for dispersing the heat.
If you ship is adequately long for its front profile, you should be able to be able to use a cooling system to circulate the heat throughout your ship and either find ways to recycle or radiate it off.
] |
[Question]
[
Assume Earth has been wrenched out of the Sun's orbit and has become a rogue planet, with its surface equilibrium temperature falling to ~-240C.
At what depth will temperatures remain "comfortable" for human life (i.e. = current surface temperature of ~15C)?
1. In areas where today the average geothermal gradient is 3.5C/100m [red line].
2. In geothermally active areas, where the geothermal gradient is much flatter [green line].
[](https://i.stack.imgur.com/Gvtw7.jpg)
In other words, how will a radical cooling of the planetary surface affect Earth's current geothermal gradients?
Will the gradient lines just be shifted 255C left? Or will it be a sort of gradual convergence like in the following diagram?
[](https://i.stack.imgur.com/htiaz.jpg)
Thanks in advance for your input!
Optional, closely related question: I assume solid ground reach its equilibrium state much faster than the oceans due to the latter's vast latent heat capacity. But once the oceans do freeze over, after 100,000's of years, would the ice henceforth behave about the same as completely geothermally inert soil, and hence trend towards -240C as well (i.e. in areas of ice far from hydrothermal vents where liquid water may remain indefinitely)?
[Answer]
Initially only the upper most part of the crust would be affected, but as time progressed the new cold boundary would spread downward. This process would be very slow due to the depth of rock and rocks insulating effect.
Making the Earth a rogue planet would in all likelihood also lead to considerable gravitational upheaval which in the short term at least would lead to a lot of volcanism which would delay things further in some locations.
Ultimately the gradients would shift to the left with the surface at -240C (with some volcanic variations) and similar gradients that we see today depending on the underlying geology. However the process might take a very long time indeed to run to completion especially at the deeper levels, possibly billions of years.
Most of the upper parts of the oceans would freeze relatively quickly and spread downwards over time, taking long and longer to freeze as the process continued due to the insulating layer of ice above. There might well be sufficient convection circulation driven by plate tectonics in parts of the oceans to keep significant parts of the lower abyssal plains free from ice. The ice that formed away from ocean vents would eventually be more rock like than soil like at such deep cryogenic temperatures.
I assume the Moon was lost when the Earth escaped the solar system, but in the unlikely event that it was retained possibly with an altered orbit it could be responsible for a degree of energy input by tidal forces.
] |
[Question]
[
So, to quote [pterosaur.net](http://pterosaur.net/flight.php):
>
> Unlike the wings of birds, the wings of pterosaurs would have tended
> to change shape under aerodynamic load - something often referred to
> as 'passive cambering'. Camber refers to the curvature of a wing in
> cross section. Because pterosaurs possessed membrane wings, the wing
> would have been elastic (though we do not know exactly how compliant
> the wing would have been) and this would have allowed the wing to
> stretch slightly when producing fluid forces (i.e. lift and drag).
> This stretching would result in a slight upward "bowing" of the wing
> membrane, thereby increasing camber. At the same time, it is plausible
> that active mechanisms (i.e. muscular actions) in the wing membrane
> could have limited passive cambering or allowed different regions of
> the wing to differ in their response to external forces - thereby
> producing variable camber over the wing. The compliance and shape of
> the pterosaur wing was likely capable of producing very large lift
> coefficients. Work by Colin Palmer and others has demonstrated that a
> pterosaur wing allowed to camber completely passively during flight
> might very well have achieved lift coefficients of nearly 2.0 for
> short periods of time, which is quite high for a large flying animal
> (by way of comparison, large birds usually max out at a CL of about
> 1.6).
>
>
>
Holy S-H-I-T
However, feathered wings have a [neat little mechanism](https://www.youtube.com/watch?v=1kztP_XTEPk) that allows them to reduce the air resistance of the wing in the upstroke and also redirect the air flow under the bird for some extra lift.
>
> Each feather has a major (greater) side and a minor (lesser) side, meaning that the shaft or rachis does not run down the center of the feather. Rather it runs longitudinally of center with the lesser or minor side to the front and the greater or major side to the rear of the feather. This feather anatomy, during flight and flapping of the wings, causes a rotation of the feather in its follicle. The rotation occurs in the up motion of the wing. The greater side points down, letting air slip through the wing. This essentially breaks the integrity of the wing, allowing for a much easier movement in the up direction. The integrity of the wing is reestablished in the down movement, which allows for part of the lift inherent in bird wings. This function is most important in taking off or achieving lift at very low or slow speeds where the bird is reaching up and grabbing air and pulling itself up. At high speeds the air foil function of the wing provides most of the lift needed to stay in flight.
>
>
>
**But would it be theoretically possible for a living creature to have a wing that's capable of both tricks? If yes, how would it work?**
[Answer]
**If the pterosaurs had fenestrations with flaps in the wing, those could simulate what feathers are doing.**
Imagine the pterosaur wing: an unbroken flap of membrane.
Now put holes in it. Under each hole is a fold which occludes the hole. The fold of the flap is forward.
On the down stroke the fold is pushed against the hole. The wing presents a uniform surface pushing against the air.
On gliding the fold is also pushed against the hole by air coming from in front.
But on the upstroke, air can pass downward thru the hole and past the flap, pushing it out of the way to allow passage. The wing thus presents less resistance to the air when moving up. This is analogous to the rotating feather trick - which is a lot less intuitive to me than a hole with a flap!
] |
[Question]
[
I have a (digitigrade) quadrupedal alien creature with one of it's front limbs having a longer metatarsals, I'm trying to visualise how it would walk with this deformity for an animation.
I'm having trouble with how the leg would act as the right, regular leg lifts up and moves forward since the deformed leg now has to carry the front half alone for the right to complete its step, this involves left leg straightening underneath the body so it can then also step forward again.
The basic wireframe looks like this: [](https://i.stack.imgur.com/GHDe3.gif)
A more detailed sketch of the front legs: [](https://i.stack.imgur.com/wM5Dj.png)
This is a painless birth defect called 'Stiltlimb' and not natural to the species; a gmo made for the purpose of a service animal, that being said the species itself is very prone to defects and the like, a struggle for the company trying to sell this new branch of science.
If anyone with can make sense of my scrounged up jargon and the scribbly drawing, I'd love some help!
[Answer]
**Orthotic lift shoe.**
These are not wild animals. They are service animals. They can get help from their owners. Their short leg can wear a lift shoe.
[source](https://rads.stackoverflow.com/amzn/click/com/B07RV65CP6)
[](https://i.stack.imgur.com/NErtl.png)
You can get custom lift shoes. Depicted is the Even Up, a cheap temporary lift shoe. In the picture, the woman has a walking cast which makes her right leg longer. The lift shoe increases the thickness of her sole on the left side, so it is a match and her gait is even. Lift shoes are helpful for polio survivors or other people with a limb length discrepancy, congenital or acquired.
Your animal can wear a prosthetic on the short side. That is nice too because I assume the long side is long for some reason (manipulating things?) and it is unencumbered by any shoe.
[Answer]
You actually have a lot of resources for visualising how odd-limbed creatures move in the 'real world'. A great example is [this cuddly chap](https://www.youtube.com/watch?v=6kCz739-XbA).
[](https://i.stack.imgur.com/Iilyo.gif)
*spoilers*
In Stranger Things Season 3, the Mind Flayer takes on a freaky embodiment of meshed animal and human corpses. Whilst technically not four-legged, it is an excellent example of four-legged lame movement being fast, agile and dangerous (see the video link I posted up-top). Obviously if you have Netflix, go support the show and give it a watch. It's worth it regardless.
I don't know how well versed you are in animation, but you should definitely play around with [skeleton rigs](https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2019/ENU/Maya-CharacterAnimation/files/GUID-5A485049-D0BD-4BBB-BE08-C3D502F17483-htm.html) in Autodesk Maya. You seem pretty good already, but there's nothing like a little experimentation.
Other examples of fully-formed rigs with limp-like movement may also be useful to you. Creatures like [the Ing from Metroid Prime 2](https://i.stack.imgur.com/1YZjn.gif) show that this can be done in an impressively realistic yet subtle way.
In any case, movement should by rhythmatic (not a constant march, more like a dance if that makes sense) and the shoulder of the affected leg shouldn't drop below the opposing shoulder at any point in movement. Hope this helps- your project looks amazing by the way.
[Answer]
As a birth defect, it would have a measured limp and the uneven gait+weight distribution would make it useless as a labor animal, not to mention leading to spinal problems later in life. I lost the cartilage in my right knee in the Marines, and the small difference in weight distribution has led contributed to posture and lower back problems over the 20 years I have had the issue.
For visualizing how it would walk, I suggest using a free 3d modeling program (like Blender) to make a quick mock-up of the creature and try to rig it for walking animation.
[Answer]
It's possible they could have sort of a second knee, allowing that limb to be "folded up" and still useful... how will they be using this limb and is it common for that species?
[Answer]
It would maybe need a brace or a supportive attachment on that limb to help it equalize its movement around the place. It can also just further extend that limb further than the other limbs and learn to move with all of them in sync together even if the movement is uneven. Like if you ever seen the movie called "[The Thing](https://www.imdb.com/title/tt0905372/)", splitface was able to maneuver around the place while having weird limbs that it randomly made.
[](https://i.stack.imgur.com/BIxEj.jpg)
Also, our regular day-to-day animals usually have 4 limbs that they move around with and usually the frontal limbs are shorter than the longer limbs at the back. The longer 2 limbs can be used to help the creature lunge/jump forward. The frontal shorter limbs can be used to grab or attack more accurately in the direction that the creature is facing. If you ever seen the multiple [dog breeds](https://www.emotionalpetsupport.com/2017/03/10-emotional-support-animal-dog-breeds/) that exist, you'll notice that golden retrievers have almost equally long limbs and they tend to gallop around more. Pit bulls and pugs generally have stubbier limbs and they don't do as good of a job at running compared to the dogs with the longer limbs. Even if they all have somewhat different length of limbs.
[Answer]
**Vertical Bobbing**
[](https://i.stack.imgur.com/Z1xO7.gif)
The front half of your creature displays a bobbing motion as it walks. The front shoulders move upwards when weight is on the long leg, and move down when weight is on the short leg.
] |
[Question]
[
An interesting idea that popped up in my previous question on the feasibility of large scale life on a gas giant was a form of energy production similar to photosynthesis, instead absorbing the EM energy from a gas giant's magnetic field to break down chemicals in the methane, ammonia, oxygen and other necessary gasses.
How would these organisms absorb the EM energy and make it useful?
As an added question, would multicellular magnetosynthetic 'plants' be able to survive using magnetosynthesis?
[Answer]
"EM energy" is light. I.e., photosynthesis. You might be able to get useful energy from the radio noise generated by charged particles captured in the plane's magnetosphere, but your plants would have to be pretty big to develop biological radio rectennae. And they would need very highly developed ion-pumping mechanisms to capture and save up teensy bits of energy from each radio photon in order to add it all together to power any single useful reaction.
You cannot extract energy from a magnetic field without destroying that magnetic field. If you want to generate energy *using* the planet's magnetic field, the only way to do that is for the organisms in question to move very quickly across the magnetic field lines, and then harvest their kinetic energy via magnetic induction. In order to get biologically-useful voltages out of that, your magnetosynthetic plants would have to be *very large*, even more so than radio-eating plants, and therefore most likely multicellular. It is perhaps possible that such plants could live in cyclones or high-speed circulation bands such that winds push them across the magnetic field lines, and that's where the energy ultimately comes from, but it seems to me that this would be a rather marginal energy-extraction strategy; you'd do better relying on static electricity in storm clouds, or thermal gradients between different layers of the atmosphere.
] |
[Question]
[
Right from the beginning, the xenarthrans--armadillos, sloths and anteaters--have been at a disadvantage. For the longest time, their home was an island continent, which made them extremely vulnerable to outside environmental changes. Case in point--the American Interchange caused by the bridging of Panama less than three million years ago. As quoted in Wikipedia:
>
> During the Cenozoic, North America was periodically connected to Eurasia via Beringia, allowing repeated migrations back and forth to unite the faunas of the two continents.[n 21] Eurasia was connected in turn to Africa, which contributed further to the species that made their way to North America.[n 22] South America, on the other hand, was connected only to Antarctica and Australia, two much smaller and less hospitable continents, and only in the early Cenozoic. Moreover, this land connection does not seem to have carried much traffic (apparently no mammals other than marsupials and perhaps a few monotremes ever migrated by this route), particularly in the direction of South America. This means that Northern Hemisphere species arose over a land area roughly six times greater than was available to South American species. North American species were thus products of a larger and more competitive arena,[n 23][69][89][90] where evolution would have proceeded more rapidly. They tended to be more efficient and brainier,[n 24][n 25] generally able to outrun and outwit their South American counterparts, who were products of an evolutionary backwater. These advantages can be clearly seen in the cases of ungulates and their predators, where South American forms were replaced wholesale by the invaders.
>
>
>
Unfortunate in the long term, so how could we toughen them up? Why, give them more space to roam at a far earlier date. (Could put them in ecological crossfire with the rodents and eulipotyphlans, but that's not relevant to the question here.) Fortunately, we have an idea on which directions some particular ocean currents took during the Eocene:
[](https://i.stack.imgur.com/f1G1H.jpg)
The current was very close to South America at the time, and if we look really closely, we can see that the Panamanian Land Bridge had just started to emerge. Now the question is: **Could that current ferry the armadillos and sloths outside of South America to colonize other lands long before the Great American Interchange?**
[Answer]
While I wish them no disrespect, there are a few mistakes in Bellerophon's answer. First of all - rafting migration most certainly does happen, and has happened many many times in Earth's history. It brought carnivores and tenrecs to Madagascar, histricomorph rodents, monkeys and amphisbaenians to the Americas, and iguanas to the South Pacific. Oceanic dispersal is a very common method of migration.
[](https://i.stack.imgur.com/NyITm.jpg)
Furthermore, we know that rafting events out of South America have happened before - examples include:
* Iguanas, from South America to the South Pacific
* *Amaurobioides* spiders, from South America to Africa
* Monkeys, caviomorphs and many others, from South America to the Caribbean
* Terror birds (Phorusrhacidae), from South America to Africa
Another error I believe the other answerer has made is the nature of oceanic dispersal. While it can be done by swimming, it seems a more common phenomenon is that organisms are carried aboard large mats of floating vegetation, washed out to sea by rivers - the Amazon commonly belches out such rafts, often of huge sizes. This also solves the food problem - a large raft could easily provide enough vegetation to supply the migrants for a long journey.
If we want to get technical about it, I can do some rough calculations. There's no data on the speed of this Eocene surface current, so I'll just assume that of a typical modern current - nine kilometres per hour, a la the Gulf Stream. Looking at a map of the Eocene world and comparing it to a modern one, I did a rough calculation that the distance from Eocene South America to the easternmost Southeast Asian islands of the time to be about 16,000 kilometres.
It would take 1777 hours, or a bit over 2 months, to traverse 16,000 km at 9 km/h.The field metabolic rate of the three-toed sloth is a measly 38 kilocalories per day, so it'd need 2,812 kilocalories for the whole trip. An average leaf contains roughly 1 kilocalorie for every 5 grams, so there would need to be at least 14 kilograms of leaves on the raft. That is *not* a stretch of the imagination whatsoever - some vegetation mats are multiton giants.
So, in short, the answer is absolutely **yes.**
[Answer]
## Probably not
Firstly as far as I know no land animals have ever colonised somewhere using ocean currents. While this doesn't mean it can't happen it does suggest it would be very unusual.
Another reason to doubt the possibility is that whilee ocean current passes close enough to the top of South America that a passing sloth might wander into the sea and swim into the current the next land it passes near is probably Gibraltar. There is a possibility of the sloth making landfall on some islands in South East Asia but we need the sloths to acess more land than a few islands. This gives a trip of somewhere around 30000 km. The fastest ocean current goes at around 10kmh so its going to take at least a third of a year to make the trip. Sloths have a slow metabolism but I doubt they can go for a third of a year without eating. Armadillos won't fare much better as they can't store much fat they are unlikely to have the reserves to make the journey.
] |
[Question]
[
You have a material that greatly **enhances electric and magnetic sources or electro-magnetism in general**.
In this world, the material, is known to be a naturally occurring liquid found in geological formations beneath the Earth's surface. It would be commonly refined into various types of fuels or blended with other liquids to achieve different proprieties and meet a variety of uses.
When this material gets used, which is purely only possible through human interaction, it generates **heat**, which becomes greater, the longer it is being used.
The ships pictured below, have to be able to transport heavy cargo, stored in containers of the same shape and size.
These ships should be able to *levitate* above the ground, while being active and, fly at speeds of up to 120km/h at a height of approx. 300 meters.
Choosing either of the pictured designs, what would be the most simple, technically possible, **engine/ moving** **apparatus**, to move such a transport, without or minimally affecting its design?
---
**EDIT:** The transports have lengths of up to 70 meters and weigh up to 300 tons, comparable to commercial airliners. I could make them possibly 30% lighter though if necessary.
I also want to clarify that a possible theory should be as close as possible to reality but *doesn't have* to strictly follow every aspect of it. It can also be related to **current theories in quantum mechanics**.
[](https://i.stack.imgur.com/GcosN.jpg)
[Answer]
**I pick 1, because it is plausibly a hot air balloon.**
It is hard to envision leveraging yourself up against the unmodified earth (i.e. no rails or tracks) just using magnetism.
But you have stuff which gets hot as you use it. You can use it to heat gas. The hotter the gas, the less dense it is. Hot enough and it has a density low enough to be buoyant and float. Enough low density gas and you can lift other objects - you have a hot air balloon. Hot air balloons are not fiction.
You can calculate the amount of lift - the maximum would be a "vacuum balloon" and so able to lift a weight equal to the volume of atmosphere of the same size. I am not sure how big your top one is because I am not sure if the lines under it are tiny people - if so, it is big. If that silver stuff is plastic (not metal) it will be able to lift a fair bit. I pick it because the shiny thing in the center I take to be the hot gas reservoir and it is more central than in the more angular brown ships.
As regards your material: you will be using it to produce heat but also to produce propulsion via ducts, propellors or what have you.
---
If you are really going to heat up your air, it is worth noting that flames (hot air) start at 600C. If your air is hot enough it will glow.
[Answer]
The fact the the material (at least from my reading) seems to be violating the conservation of energy opens many doors. The most straightforward application of this would be to apply it to existing e-mobility solutions. (i.e. electric planes, cars, busses).
You mentioned this "enhanced" emf sources. This could be applied to energy storage systems to yield a greater energy/mass ratio. This could also increase the efficiency of the electric motors. As most motors currently are somewhere between 78-92% efficient. (<https://www.engineeringtoolbox.com/electrical-motor-efficiency-d_655.html>)
When Li-Po batteries are cycled they produce large amounts of heat. The bigger the battery and faster the draw, the more heat is produced and I imagine with your enhancer material would only increase this effect, especially because you said its use also creates heat.
In addition, any electrical component produces some amount of heat. Specifically in an electric motor, heat is produced in the windings mainly due to resistance. To get more magnetism (more torque) for the same form factor you need more amperage flowing through more wire loops. More loops in the same form factor mean smaller diameter wire. Smaller wire and more current mean more resistance and more heat. When I read your question I imagined the liquid to have some sort of damping on Ohm's law. I pictured instead of V = IR, V= IR/4.
So while there is less heat from the motor itself, there is more from the batteries, the liquid being used in the batteries, and the liquid in the motor. All in all a net positive amount of heat. This heat could be compensated for by using more active cooling, like the cooling system in your car's engine, (powered by the better batteries) or passively cooled in-flight. Passive in flight cooling, like whats used on jet engines today, (<https://www.sae.org/news/2018/08/parker-aerospace-and-gkn-aerospace-to-develop-passive-cooling-solutions-for-next-generation-aircraft-engines>) uses the lower ambient air temperature and high air flow rate to cool very hot components of airplanes that would otherwise melt.
In regards to the ship, I would recommend the second one as it seems to have the center of gravity most centralized (good for an easily controllable and build able ship). In addition it has a flat-ish area underneath that could conceivably house props.
[Answer]
For achieving flight, you have essentially three options:
### Hydrostatic lift
As mentioned in another answer, superheating gas allows you to produce lift, essentially building an airship. The downside to this is that this requires an enormous volume as a lift body attached to your ship, which significantly alters their shape.
### Hydrodynamic Lift
You could alternatively superheat air inside a compressor, and eject it out the back, making a fuel-free jet engine. This generates thrust, which can be turned into lift using a pair of wings. The downside is your craft now is not only the size of an airplane, but looks exactly like an airplane.
### Pure thrust
If you don't care about efficiency at all, you can point your engines downwards, and lift yourself on pure thrust. Since you are using free energy, you don't care about fuel efficiency, but the thing will be still enormously loud, highly unsafe to any engine failure, and inferior to an airplane design
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**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.
I'm writing a cyberpunk novel where one of the characters has an augmentation that allows them to echolocate.
The idea is that there is a device on the center of his forehead (is there a more optimal location?) that produces extremely low-wavelength wavelets of sound at a very high rate. The wavelets are ultrasonic, so he has to have some kind of ear-implant that transfers the information to his brain. Since human brains aren't adapted to processing sound with such extreme precision, he also has to have a brain implant that assists with the necessary computations.
My question is about how powerful this ability could get, assuming there are no restrictions on how fast the implants work.
According to [wikipedia](https://en.wikipedia.org/wiki/Animal_echolocation#Frequency), bats can echolocate with a frequency >200 kHz. Let's assume a frequency of 200 kHz. $\lambda = \frac{343 \;m/s}{200,000 \;Hz} = 1.7 \;mm$ is the wavelength of the sound, right? Does that mean that anything wider than 1.7 millimeters could hypothetically be detected? Obviously, this can't be true at large enough distances, so I don't think I'm approaching the problem correctly.
What is the upper bound on the frequency that could be used? What is the relationship between resolution and distance? How do both of these things change if the echolocator is moving at high speeds?
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## Resolution
The 1.7 mm wavelength describes your best resolution for identifying details.
In eyesight, the brain is engaging in a pattern of scanning the same object at multiple angles (see [saccade](https://en.wikipedia.org/wiki/Saccade)). The brain merges the data interferometrically (much like a hologram). The result is that you can "see" smaller details than your best angular resolution.
So, some math :
$K$ is the smallest gap size that can be recognized. It's actually a different number than your wavelength, based on the density of receiver cells and overlap between layers of those receiver cells. You'll have to use some imagination to determine what $K$ is. For some additional information, natural rod cells are about 100 microns in size.
Angular size of any object, $ \delta \approx {d \over D} $
Where $d$ is the size of the detail (in any units) and $D$ is the distance from the observer to that detail (in the same set of units).
If you imagine this kind of acoustic sight as a video screen, the number of "pixels" of information $n$ received by the observer watching an object of size $d$, $D$ far away is:
$n = ({\delta \over {2K}})$
Some research has shown that lighting conditions can provide up to a 10x gain in the number of "pixels" of data received.
There have been studies done on the lower bound of information (in bits) that the human brain needs to recognize a detail (<https://people.csail.mit.edu/torralba/publications/howmanypixels.pdf>) :
| #bit (n)= | 4 | 8 | 16 | 32 | 64 | 128 |
| Color | 20% | 40% | 60% | 80% | 90% | 100% |
| Greyscale | 10% | 20% | 50% | 70% | 90% | 100% |
And, speaking of color, if you'd like to have color for ultrasound "vision", the transmitter and and receiver would need to use a few different frequencies spaced some distance apart, but not too far apart.
## Effect of Rayleigh Scattering on Ultrasound "Illumination"
What may be a limiter with ultrasound is Rayleigh scattering, which happens in the acoustic domain just as it does in the optical one.
Much like a flashlight, the "ultrasound" receiver is generating the phonons that are bouncing off the target and back to the receiver.
If you are using omnidirectional illumination, the intensity of those phonons ($I$) drops off with the square of the distance $I = {I\_0 \over D^2}$
For more focused illumination (like a flashlight) $I = {I\_0 \over {D sin \theta}}$, where $\theta$ is the half-angle of the cone the flashlight covers.
Overlooking a number of parameters, Rayleigh scattering adds a $1 \over {D^2 \lambda^4}$ term to this effect, where $\lambda$ is your ultrasound wavelength. Putting that all together, for omnidirectional illumination, the total equation would be :
$I = {I\_0 \over D^2} - {I\_0 \over {D^2 \lambda^4}}$
(it's actually much more complicated than that - especially for acoustics - the above is a very rough estimate. For details, check out : <https://en.wikipedia.org/wiki/Rayleigh_scattering#Cause_of_the_blue_color_of_the_sky> and, for acoustics, <https://asa.scitation.org/doi/full/10.1121/1.4918298>)
## Reflectance and Camouflage
This might be starting to feel ridiculous. If this is a commonly used technology, some people will have studied how to hide from it.
The amount of reflected energy, $R$, is equal to the intensity of the phonons "illuminating" it ($I$) and some material-specific constant describing the material's ability to absorb or reflect the energy ($\epsilon$). Reflectance ($\epsilon$) ranges from 0 to 1.
$R = I \epsilon$
## Summarizing Illumination : Detection in Relative "Light" and "Dark"
For the receiver to be able to detect an object at range, enough reflected intensity needs to be picked up by the receiver to overcome noise ($N$). You'll have to decide for yourself, but in an urban environment where ultrasound is used for many things it may be very noisy.
The equation is :
Signal-to-Noise ratio, $SNR$ must be greater receiver gain/sensitivity. $SNR = {db(R A)\over{db(r^2) db(N)}} = { db(R A) - 2 db(R) - db(N) }$
db() is a function transforming the intensity values to decibel-meters (dbm)
For some ideas of real-world gains, I found a quick ultrasonic receiver online with a gain of 19 dbm.
## Gains from Pattern Recognition
Other studies have shown gains of up to 40 dbm from observing a signal and noticing patterns that are indicative of a signal.
I apologize for not pre-calculating all of that into a final result. I would recommend, for a set of frequencies, pre-figuring how far a X-watt ultrasonic "lamp" will be able to illuminate in urban or quiet conditions.
## Pratical Example
A character in your cyberpunk settings has tracked a target into the woods and is hunting in the dead of a moonless night by echolocation. You've pre-determined that, in this environment, the ultrasound "lamp" the character is using is only effective out to 300 feet.
Actually, the prey is savvy and has on camo gear designed for ultrasound, and the lamp is only good to 150 feet. However, the hunter is actively searching and you've pre-calculated that increases the effectiveness of the lighting to about 225 feet.
Based on the frequencies chosen, the target's size, and the distance, the cyberpunk is only getting 8 "pixels" of information : there is only a 20% chance of the hunter "seeing" it's quarry. Should have paid for the color upgrade - the chance would have been 40%.
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Suppose you had a tower-like mega-structure, rooted all the way into near-infinite geo-thermal energy of the Earth's crust, connected to the ocean such that water is not a limiting factor to the super-structure, and extending fully through the atmosphere into space. Is there a plausible way for this mega-structure to maintain a powerful and permanent cyclonic storm around itself?
Specifically, I am interested in a "cyclonic storm" defined as a sort of super-hurricane, a violent, rotating weather system maintained by a vertical superstructure in it's eye. The storm system could be layered along the same lines as earths atmosphere, or it be organized beyond them.
(Secondary questions: how wide could the eye be? How wide could the storm get?)
Perhaps by raising heat and moisture into the upper atmosphere and distributing it in a controlled way and/or placing a rotating sunshade in space to control the the thermal contribution of the sun? Perhaps by thermally superconductive materials transferring heat to water or cold moist air? How could the weather be made to spin around a super structure?
EDIT: I received notification that this question could be considered a duplicate of the question, "How can I ensure my Evil Tower is always stormy?" The primary differences are the scale and that the storm is a cyclonic storm around the structure, not floating overhead. The tower-like mega structure in my question reaches space, and would be between 100 and 200 km in diameter at it's base. The storm surrounding it would be broad and powerful enough to affect dramatic watershed change in a radius of 100s of km, and make foot traffic to the structure impossible. Study of Cyclonic storms and the answers I've already received indicate the answers to "How can I ensure my Evil Tower is always stormy?" would not produce these effects. This is not scary cloud, it is a meteorological catastrophe.
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Larry Niven's *The Ringworld Engineers* uses the concept that superconducting material has the same temperature everywhere along its length — in his case, a coil of cable (paraphrasing) between the focus of some solar cooking plants and an ocean. The ocean boiled. If the building's exterior were made of superconducting material, the geothermal high heat must try to equalize in the upper atmosphere.
But, this would only work if the region the building was built in was basically a [cold, humid climate](https://en.wikipedia.org/wiki/Humid_continental_climate)— lots of cold water vapor in the atmosphere trying to deal with the super heated building exterior. Hot building, cold moist air, storm.
Why would you want this? Because you want the heat differential to power the building (think [thermoelectric generator](https://en.wikipedia.org/wiki/Thermoelectric_generator)). You don't want the heat on the inside, cooking the occupants. You want it on the outside. The storm is the excess heat boiling off into the moist, cold atmosphere (not unlike a [cooling tower](https://en.wikipedia.org/wiki/Cooling_tower), but on a much more grand scale).
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**Edit**
Just to bring the comment discussion into the answer. Let's assume a cylindrical building with a diameter of 150Km. That's bigger than the eye of many storms, but this building is producing a constant and substantial amount of heat all along its outer shell.
Wikipedia has a reasonable [article about cyclones](https://en.wikipedia.org/wiki/Eye_(cyclone)), and that article includes this lovely infographic:
[](https://upload.wikimedia.org/wikipedia/commons/4/4f/Hurricane-en.svg)
See that lovely red spiral in the middle? That's your building. Heated air spinning with the storm as it rises along the outer wall.
Like all large storms, the spinning comes from the [Corriolis force](https://en.wikipedia.org/wiki/Coriolis_force), and considering how stable this storm is (and, frankly, how large), it will spin.
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So one of the supernatural elements in my urban fantasy story is a system of "aura-syncing" that explains how various supernatural abilities extend to one's clothes and belongings. A full explanation can be found [here.](https://worldbuilding.stackexchange.com/questions/111135/double-checking-my-worlds-rules-for-making-magic-extend-to-clothes)
Tl;dr: Every human projects an invisible aura 3 inches from their body, and any solid object that spends 5 minutes completely encased in this aura becomes "synced" to that aura and is treated as a part of their body for the purpose of various abilities as long as it's at least partially within their aura when that ability is used. The aura an object is synced to will be changed again the next time it spends 5 minutes encased in a new aura.
Now, the main character is one of a few people on Earth who has the ability to *see* these auras. When he uses this ability, the entire world turns pure white with these sort of cell-shaded borders, and the only things that have any color are human auras and any objects that have been synced to an aura. Every person's aura actually has a color assigned to it, which can be absolutely anything except white (or any color too close to white for the average human eye to distinguish), though darker colors are rarer. And the main character will see any synced objects as being the same color as the aura of the person it's synced to.
Now, the fact that this applies even to the tiniest particles or grains of sand is a pretty crucial plot point, and it got me to start imagining what a beach would look like in this "aura vision", with every single grain of sand a human's ever sat near for five minutes being imprinted with that human's unique color.
Right away it sounds like a really striking image, with a technicolor pattern of human bodies imprinted into the sand from all the beachgoers lying down on it, slowly eroded by the sand being kicked around until the colors mix together, only to all be re-imprinted again. But I was wondering if there'd be anything else to the picture.
***Is there anything about how sand moves and scatters on a beach that would cause other patterns to emerge, or anything else that would affect what my protagonist would see?***
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I remember you original question --- very interesting!
As for the sands of the shore, I honestly don't think the effects will be quite as spectacular as you might be hoping.
Some possibilities:
1. **Ideal situation** is where there is a calm sea and no breeze to speak of all on a warm day that is a holiday during beach season. This will give you maximum number of people with a minimum of sand movement. If your aura-sighted person knows what colour, hue and saturation to look for, she will be confronted by thousands of latent impressions. The people that stayed (in one place) the longest and were the last to leave, will naturally leave behind the most pristine impressions. She might be able to see a more saturated area that represents the torso with perhaps smaller patches where the head and arms and feet rested. Other impressions will be less clear: if someone laid on the sand for a couple hours, relatively late in the afternoon, and then left, chances are good his impression will be at least somewhat disturbed. People running might churn up portions of the impression, but she should still be able to make out a blobby outline at least.
2. **Less Than Ideal Situation** is weather conditions as above, but the person in question lay on the beach during the morning and then got up to leave around noon when once the place became too crowded. Chances are very good her colour sand will be churned up and locally scattered. Perhaps built into a sand castle along with other people's sand who were lying nearby. Our aura-sighted girl will find it very difficult to determine what the actual colour scheme is. She might be able to get a general description like "greenish", but it will mixed in a three (or actually four) dimensional cloud of other colours and saturations.
3. **Least Ideal Situation** is where an early morning person lay on a very popular spot that was eventually taken over several times during the day and also got churned up, built into sand castles, which got dashed down and scattered, and then smoothed over again.
Note also that for each of these ideal situations, our aura-sighted girl will have to contend with particles that have been synched on the days and weeks previous.
1. **Very Likely Situation** is where our girl will have to contend with normal seaside weather. Beaches are very labile. They don't stay in one place. The sands are constantly shifting as winds blow them this way and that. Tides cause sand to be heaped up and drawn away again. If she takes a look at the beach on a windy day after the tide goes out again, she'll be confronted not only by the churned up and commingled colours of the day and the days previous, but also the colours of sands that the winds have exposed from higher up and the sands that the waters have deposited on the beach. The longer she delays, the more the beach will evolve and obscure any impression she might have been able to make out.
2. **Worst Case Scenario** is of course that her investigation has been hampered by very bad weather. Hurricane Sandy is about to visit the Big Pomegranate and the beach is inaccessible. By the time our aura-sighted girl can get out there, there is simply no beach. All the synched sand has been washed out to sea. Looking out into the water itself will be no help, as her sight will be blurred by all the water molecules that have become synched to hundreds of millions of people all across the eastern US whose (treated) piss & bath water has made it out to sea...
PS: you can buy coloured sands in most any craft shop. Buy a few different kinds and mix em up in a jar. See for yourself what our girl will see!
PPS: *EDIT* --- I'd imagine that even the very best case scenario impression will look something like a luminol image:
<http://truejustice.org/ee/images/perugia/frontpage113/11355.jpg>
And being a popular beach, image upon image upon image.
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A **three inch radius** and **five minute exposure** time required for aura syncing means that the vast majority of beach sand would **stay sand colored**. Only on popular beaches in places like California, Florida and Hawaii where lots of people go and lay in the sun would you see colored blotches of sand.
The protagonist would see human-sized stripes of sand where people lay. After the people get up and leave, these stripes would eventually get smudged (during the night, during weekdays when there are fewer sun worshipers, etc).
High tides, wind and storms would also mix the surface sand. Over the long term, you'd get a smudgy mixture of white and sand.
Remember, though: due to the **three inch radius** and **five minute exposure** time required for aura syncing, the vast majority of sandy beaches would just stay sand colored, since so many people go to the beach and play (in the surf, on the sand, etc) instead of just laying there.
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A Dyson sphere is a spherical megastructure built around a star with the goal of capturing all of the energy output of the encased star and making that energy available to the controllers of the megastructure. Producing as much usable energy as possible is the idea.
**If the encased star were artificially compressed or expanded, would the controllers of the Dyson sphere be able in increase the net energy output?**
Note that the artificial compression or expansion would require energy, not only to initiate it, but to maintain it. The initial energy requirement may be ignored, but the energy used to maintain this effect would be siphoned off of the energy the Dyson sphere collects, hurting the net energy output.
Ignoring the details of *how*, you may assume the Dyson sphere is capable of absorbing 100% of the star's energy output, and is able to store, transmit, and use the energy it collects with 100% efficiency. The machinery used for the compression or expansion is built into the megastructure.
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Yes, they could somehow increase the star's gravitation. This would accelerate its nuclear processes and the star would find a new equilibrium at a higher brightness. It requires energy to set up, but not necessarily any energy to maintain it; if, for example, you replaced the star's inert iron core with a denser element, that would be enough (provided the new core is stable, that is).
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The star's energy output perfectly equals it's gravitational binding energy because the energy output is what keeps the star from collapsing under it's own gravity, it is why stars eventually stop being stars when they no longer have a exothermic nuclear fusion reaction to fuel them. This is the equilibrium of energy output and size of the star. The star existing in this equilibrium means that altering the size in any way requires more energy than you can gain from the star due to the laws of thermodynamics.
Although the star exists in equilibrium, it does not mean that it doesn't have different energy levels that don't exist in nature. Stars theoretically can have locally stable energy states that are not the natural one that all stars share. Maybe if you were to add enough energy to the star to reach temperatures on Planck scale, you would reach different physics than we currently know and gain energy afterward. This wouldn't really make much sense because Planck temperature is 1.417×10^32 and even siphoning millions of stars will not give you enough energy to get to that point.
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I am working on a solar system for a world where I intend to place my stories. This world should work by the laws of physics as we understand them so that, even though magic is a thing that exists in this world, the world doesn't need magical hand waving.
Here is info on the system that is immutable right now:
The solar system is a binary system made of up a main sequence star with a mass of .5 solar masses and a radius of 556,560 km and a white dwarf star with a mass of .5 solar masses and a radius of 9,500 km. This is orbited by double planet in which each planet is approximately the same mass as the Earth. This causes tidal forces of 3x that of the Moon on the Earth.
This brings me to my two questions:
1. Would slight accretion of matter onto the white dwarf via the corona of the main sequence star cause enough radiation that life would be impossible?
2. And if so, how would placing their orbital separation large enough
that the white dwarf would be outside the corona of the other star
affect the temperature of the planets as one of the stars would
always be significantly closer to the planet than our sun is to us
on Earth?
In reference to the second question to be outside of the corona, the stars would have to have a constant separation of at least 8,046,720 km with an orbit eccentricity of 0 meaning that one of the stars will always be between 0 km to 4,023,360 km closer which would mean at the higher scale about 2.7% closer to the planet than the Sun is. With that orbital separation they would have an orbital period of 4.8 days. Also that question assumes that having a total luminosity equal to the sun for the binary stars. So individually they would have about 2.6e26 for the main sequence star and 1.1e26 for the white dwarf.
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This largely answers your questions: [Habitability of binary star systems](https://en.wikipedia.org/wiki/Habitability_of_binary_star_systems)
As for radiation, the size, composition, and activeness of the planet's core can determine the strength of its magnetosphere. Which is the invisible shield exerted by the planet that can deflect cosmic radiation.
As for life itself, some life is better than others at resisting the effects of radiation. Extraterrestrial life itself could be structured differently to be more impervious to radiation. Human advancement alone may be able to solve this problem some day as well.
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If your planet has a P-type orbit any accretions between the 2 stars should be largely harmless to your planet. If your planet has an S-type orbit the distance between the stars necessary to maintain that orbit would be great enough that accretions shouldn't be to much of an issue.......
however, as with all cosmic disasters, if it's large enough and hits just the right spot it's all over.
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If each planet is approximately the same size as Earth, but tidal forces are only three times those caused by the Moon, then they are separated by a distance of approximately 1,154,527 kilometers, or about 3 times the distance between the Earth and the Moon, with an angular size of about 0.287 degrees- for comparison, the Moon has an angular size in the sky of about half a degree. They will have an orbital period about each other (or "month") of about 101 days.
From all that, we can conclude that the double planets will have no significant effect on the amount of light or radiation they each receive, and we can treat them as separate, individual planets as far as habitability in relation to the stars is concerned. That's kind of too bad, because if it was a close binary planet, then we could rely on the shadowing effect to reduce the problematic effects of the white dwarf.
A main sequence star of 0.5 solar masses will have a luminosity of around 6-7% that of the Sun (the luminosity of a compact white dwarf should be negligible), so to get the same insolation as Earth the double planet system will have to orbit much closer- about 37,400,000 kilometers. That's a little over 9 times the separation between the two stars, so the orbit should be stable. The year would then be 45.65 days- less than half the length of a month!
It seems likely that such planets would be tidally locked to each other, though certainly not *necessary*. If they are, the month is equal to the sidereal day, and each one will be fixed in position in the other's sky. That would make the solar day equal to
$\frac{L\_{Year} L\_{Month}}{L\_{Year} - L\_{Month}} = ~-83.27 Earth days$
assuming prograde rotation of the double planet (where the negative sign indicates the sun crosses the sky in the opposite direction from what you normally expect), or $~31.44 Earth days$ for retrograde rotation. Ignoring the effects of the sun wobbling back and forth due to its own orbit around its binary partner, anyway.
If you magically assume that the luminosity and year length are the same as they are for our Earth & Sun, then the solar days assuming the double planets are tidally locked to each other become $~139.68$ and $~79.15$ Earth days, respectively.
The distance from the Earth to the Sun varies between 147,500,000 and 152,600,000 km over the course of a year, a variation of about 1.7% on either side of the mean. Assuming perfectly circular orbits, the change in distance between either lobe of the binary planet and the main sequence star would vary between a minimum of $0.25AU - 4,023,360 km - 577263.5 km = ~0.219AU, ~32,798,844 km$ and a maximum of $0.25AU - 4,023,360 km - 577263.5 km = ~0.281AU, ~42,000,091 km$ for the low-luminosity, close in orbit, giving a variation of 12.3% about the mean; or between $1AU - 4,023,360 km - 577263.5 km = ~0.969AU, ~144,997,247 km$ and $1AU + 4,023,360 km + 577263.5 km = ~1.03AU, ~154,198,494 km$, for a variation of about 3.1% about the mean.
Insolation in the temperate latitudes varies by much more than 12% between summer and winter solstices, so I'd say even the most extreme option here should still be survivable, although there would be notable planet-wide seasons with not-very-straightforward sum-of-sinusoids patterns induced by these variations, on top of whatever you might get from inclination of the double planet with respect to its orbit around the suns. Expanding the orbit a bit might be a good idea as well, since these sum-of-sinusoids variations in distance will result in more equal time in the hot vs. cold regimes, and thus more time in the hot regime, than the Earth experiences due to orbital eccentricity.
So, the only thing you really need to worry about is radiation from the white dwarf, and the effects of eclipses of each star by the other. Most of the time, the white dwarf will just be a bright speck in the sky that contributes little to the warmth of the double planet, but slightly increases the UV and X-ray load. That should be quite survivable with a sufficiently thick atmosphere. Occasionally, you'll get a break from the excess UV due to eclipse by the main sequence star. The low luminosity of a white dwarf means we can pretty much ignore the small reduction in insolation due to its eclipse. And, since white dwarfs are tiny, transits of the main sequence star by the white dwarf should also have negligible impact on the insolation the planets receive.
This is, however, a cataclysmic binary. It's on the outer edge of being such, but it's likely to have recurrent nova events with a frequency on the order of decades- maybe centuries. If a nova event occurs while the white dwarf is in view of one of the planets, it's going to be sterilized. And not just the side of the world facing the star- thousands of times solar luminosity is going to mess up the entire planet. So, we need to figure out what the probability is that the white dwarf will be eclipsed from the point of view of the binary planet at any given time. That's rather complicated to do precisely, but we really just need an order of magnitude, so we'll consider just one lobe of the binary planet at a time.
For the 1AU orbit, the average angular size of the main sequence star is about 0.4272 degrees, and the total angular deflection of the white dwarf is about 3.08 degrees. In reality, it will spend more time at the edges of its travel, out of eclipse, than it will in alignment with the main sequence star, but we'll be generous for order-of-magnitude estimation purposes and assume it spend equal time in all angular positions. Half of the time it overlaps with the main sequence star, it will be in eclipse, which works out to about 7% of the time. That means that, for any given nova event, there is more than a 93% chance that one half of the binary planet will be sterilized, and much more (because the events are not uncorrelated) than an 87% chance that both will be sterilized. If novas occur on a timescale of approximately once per century, that means there is an expectation value of about 115 years before all life in this system is destroyed.
Bummer.
For the closer, low-luminosity orbit, the angular size of the main sequence star is about 1.7 degrees, while the angular deflection of the white dwarf will be about 12.28 degrees. That gives a rough 13% chance of being in eclipse, which still leads to a *generous* expectation value of 132 years before all life is wiped out.
In summary: Most of the time, accretion and variations in orbital distance should be within ranges that are conducive to life, assuming that the planets otherwise have good conditions. But the occasional outbursts of nova radiation from the white dwarf due to long-term accretion would indeed make life impossible.
To fix this, you will want to give the binary stars an orbital period of *much* longer than just a few days, to ensure the white dwarf remains quiescent, and as a result you will want a larger and more luminous main sequence star so that you can put the binary planet at a large enough distance that the orbit remains stable and it still gets enough light.
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In my (fantasy) world, a civilization sets off a superweapon that releases so much heat that it glasses an entire desert a little smaller than our Sahara. Is this feasible without killing an entire earth-sized planet's population or worse? What would the side effects be?
Edit: To clarify - The weapon backfires by accident. I'm imagining a massive (purely-thermal) explosion in the middle of said desert as the source.
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# How much sand are we dealing with?
The Sahara Desert is about 9,200,000 km$^2$. Lets say we want to glass everything down 10 meters. That is 92,000 km $^3$ of sand, or $9.2\times10^{13} \text{m}^3$. Lets just assume for the sake of argument that the whole thing is covered in sand (its not).
The density of sand is around 1500 kg/m$^3$ for a total of $1.4\times10^{17} \text{kg}$
# How hard is it to melt sand?
[This paper](http://rruff.info/doclib/am/vol72/AM72_273.pdf) on the properties of silicon dioxide gives molar heat capacity varying from 44 J/K at 300K up to 81 J/K at the 1700 K melting point, and a molar enthalpy of fusion as 9395 J.
One mole of SiO$\_2$ is about 60 g. Integrating from 300K (which is about desert temperatures) to 1700K and adding the enthalpy of fusion gives 108 kJ per mole, or 1800 kJ per kg.
Multiply required energy by mass and we get $2.4\times10^{23} \text{J}$
That is 240,000 Exajoules, or 59,369 Gigatons of TNT, if you prefer. Since not all energy would be directed into the ground/sand, you would expect to at least double the blast energy.
# How big of a blast is that?
EDIT!!! Major math errors! My original edit forgot that I was using kJ and was low by a factor of 1000. Your blast delivers about 20% of a dino-killing asteroid just to the sand! If you assume that at least as much energy is delivered to the atmosphere in heat and shock waves, then you pretty much have an extinction level event on your hands. Good luck!
About the same energy as an [asteroid impact](https://en.wikipedia.org/wiki/Impact_event#Frequency_and_risk) of 1 km diameter (which happens every half million years or so). The last mega asteroid hit was Chicxulub which was probably around 240,000 Gigatons of energy released.
An 8 on the [VEI index](https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index). La Garita Caldera was the most powerful volcano of the Cenezoic (and the biggest explosion of any sort since the Chicxulub impact) with an estimated energy release of 250 gigatons. This produced enough magma to fill Lake Michigan.
So your weapons is going to be around the scale of Garita Caldera. It was probably an order of magnitude more powerful than the [Tambora eruption](https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora), which caused pitch black skies for over two days within 600km, and the 'year without summer'. So your explosion will be a worldwide event; though fortunately not as worldwide as a dino-killing asteroid.
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As Kingledion pointed out in his answer, an explosion that can do that kind of thing is going to be pretty hard. Explosions are pretty inefficient at this kind of thing because they waste a lot of energy in the wrong direction on things that aren't purely thermal.
Luckily for you (but not for your desert) you are working with backfiring magic, and not a chemical or nuclear explosion.
You are going to need temperatures of around 1,760 degrees Celsius (3,200 degrees Fahrenheit) to melt sand and rock.
So say you have your evil mage. He decides to glass his enemies kingdom so he writes a very localized magma spell that will start and spread along the ground to cover all the borders of the kingdom. He calls forth all the dark energies, starts to spell, but gets confused and uses his own coordinates instead of his enemies as the starting point. And since he was exiled his "kingdom" is the desert waste. So the spell starts as a field that magically magnifies the ambient temperature ten fold, and it spreads out toward the borders of the desert, melting sand and stone and igniting brush as it goes.
The spell is designed to be purely thermal, and directed toward and through the ground.
Thankfully it's a pretty dry desert, and so there isn't much to burn, meaning no fire storm, but there is a huge thermal plume that goes up from the cooling sand which causes some big storms around the planet for the next weeks.
But since it wasn't an explosion there was no crater, no debries thrown up into the atmosphere, no shock wave or other things like that.
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I think kingledion's answer shows what would happen if this were an explosion with the glassing of the desert as a side effect. But you still may be able to make it work with less disastrous consequences by tweaking the weapon itself - so that the glassing is the primary consequence, not a side effect of an explosion or other destructive effect. Sort of having your weapon go off with a great pouf, instead of a big boom.
The idea I had was to focus in on a chemical-type magical weapon, instead of an explosive type one, where the "going off accidentally" spread a great, low lying cloud of particles (hence the great pouf instead of big boom) which slowly settled down and converted the sand into glass - basically, an area-effect weapon to begin with, designed to spread its effects far and wide with few extra effects outside that area. It could work chemically with "add compound x" to turn sand into glass, or thermally if it produces *a lot*, a lot of heat to melt the sand but doesn't "waste" effort with anything else, or magically with some sort of transmutation (turn-it-to-glass) or petrification spell (turn-it-to-stone) which for some reason works out as glass when starting from sand. You would get a great area with a thin layer (few inches?) of glass over the desert, centered on the weapon's location. It would either be spreading out equally from the center, or slanted with prevailing winds, with irregularities from geography and the eddies from local breezes.
Alternatively, you could have some kind of catalyst-reaction spell, designed to turn one thing into another (again, specifically to glass, or else to stone, or to something else which just ends up as glass when added to sand). It could be designed to convert an area, or better yet a complete conversion of a "single object" only nobody thought of what might happen if it touched the *ground*, or else natural variances should have formed boundaries (just what was actually hit, *this* rock or *that* stump or *the other* pocket of soil) but for some reason the sand was similar enough in composition to act like a "single thing" for the spell, and so the spell just kept going, pulling (too much) energy from its caster, or feeding itself by the energy it took to make the change, until it ran out of steam after having eaten the whole area. In this case, I would expect the glass layer to be much deeper at the center where the reaction was spreading downwards as well as outwards.
I would expect the minimum aftereffects to be storms, local and global *and* short and long term shifts in weather and winds from the alteration of the landscape, extreme flooding when it rains, things like that... because the air currents, heat absorption, and living ecosystem will all be altered by the substitution of the desert to the glass plain.
Additionally, I would expect some aftereffects specific to the *method* of the change - like using just heat to glass over the dessert would cause violent winds (difference in air temp and pressure), warming the local area (sahara-size means "local" is probably the whole continent and some nearby ocean) a *lot* and potentially leading to fires in nearby areas, more storms from the abrupt shifts in the winds, in evaporation and condensation, from heat retention, and a host of other things. If the change is chemical-analogous instead of just thermal, then I would expect the prevailing winds to play a huge role in side effects - lesser amounts might travel very far beyond what areas get heavily doused for the glass desert effect, and what a light dusting would do to different areas (ecosystems, foliage, animals) will have its own aftereffects (not to mention any actual aftereffects the weapon would have had if used correctly). If the change was catalytic, then I would guess there were aftereffects with tetonic motion (since it would be spreading downwards as well), and the way the ground shifts and flexes will change from a area made of loose sandy soil to a stiff brittle glass disk.
But despite these side effects, using a method more targeted to your glassing than an explosion should let you avoid some of the earthquakes and tsunamis caused by shockwaves, or cooling from where suspended soot and dust in the atmosphere shade the sun's light and warmth out, or any number of other consequences that might make this a planet-destroying incident. It would still be plenty serious, with violent winds and storms, and slowly altering weather patterns for decades (which is kinda the point of such a big disaster), but it should be survivable.
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What would happen if two spaceships with Alcubierre warp bubbles were colliding? Would the space bubble collapse? Would they reject or push each other? Would they survive it without problems?
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This question is well above my metaphorical pay grade, but I would assume they would throw each other MASSIVELY off course if they were approaching each other at a sharp angle.
If they were traveling perpendicular to one another and passed close enough, I assume whichever one hit the expanded space behind the other first would break the speed of light barrier, meaning it would either grow infinitely dense or it would instantly and infinitely break down into pure energy.
If they were traveling parallel to one another, no idea.
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I imagine if a 'faster' alcubierre enabled craft (as in their bubble of real-space was being flung across the universe at a faster relative speed) ran into the back of another ships alcubierre 'wake' then the compressed section of time-space from the first craft would collide into the distended section of time-space of the second craft.
As the space is compressed and distended at the same time it would end up a sort of zero-sum equation. Once the rear of your alcubierre bubble is collapsed then the forefront would also be unable to hold as far as I understand it. (as a double effect of compressed and distended space-time around a bubble of normal space-time is how you are propelled at FTL speeds)
If however they were to crash on a perpendicular course then the compressed 'front' of your craft may not stay as the most compressed section. If the side of your alcubierre bubble is the most compressed section briefly then your path may be altered, possibly to disastrous effect.
but hey, what does a cat know about theoretical FTL devices?
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Which direction is the best way to go if you were to have to leave Sol and travel 500 ly away to find habitable planets to set up long term colonies?
Core-ward?
Rim-ward?
Towards the core through the Orion-Cygnus Arm?
Towards the Carina-Sagitarius Arm?
Is there any difference in the direction?
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This takes place in roughly 2300 CE.
We have FTL drive capable of 10c, but it's not used for exploration much. Originally several ships were sent off to check out worlds for habitability near by when FTL became available, but that program ceased/went ignored when we found the first habitable world... which we promptly colonized. All or most ships with FTL mainly do work in the Sol system with some sending colonist to this 2nd world and returning with goods (I think this actually stopped by this time due to other things, but not important here. I forget the exact timeline off the top of my head.)
The FTL Space telescope I asked about in another question would be about 2000 Lightyears out at this point maximum with non-stop flight, so they're probably a little closer in than that.
The colony ship is actually 5 colony ships that want to settle on separate but relatively close by planets ^.^
The trip takes 50 years. They are going the max speed things can go for them. They may have sent "probes" out 5 to 10 years prior.
This isn't an "urgency" thing, but more of a political, get away from the morons thing, They could theoretically last forever out there without landing on a planet, but we like planets so want to colonize new worlds and set up to build a new civilization.
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There are supposed danger zones and a "galactic habitable zone". I'm just not sure where they are. They know there are habitable planets out there, but not where they are. Suppose they know what we know more or less, but want to randomly come across these worlds which way would they go? Or is 500 ly not significant enough of a distance to enter a danger zone/exit the habitable zone?
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**We don't know yet.**
They're going to want to head towards the nearest cluster of five habitable-looking planets. Unfortunately, we can't really say where that cluster is at, given our current technology level. Scanning planets with a telescope will be a MUCH better idea than sending ships off in a hopeful-looking direction, so you'd want to initiate a major star survey to find a cluster of hopeful-looking planets, and then go towards them. There's likely to be habitable (or at least terraformable) planets in all directions, so it will be a matter of which direction has the closest cluster.
Unfortunately, we don't know the answer to that yet. Our ability to analyze exoplanets is still in its infancy, but I suspect that by the time we have FTL drives, we'll have a much better idea of what kind of planets are around us.
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You should not consider core and rim-ward in this scenario.
The Milky Way is around 150 000 light years in diameter. The proposed 500 light year travel is just 1/300th of that. It's like the difference between crossing the US from coast to coast and crossing from the Statue of Liberty in New York over to Central Park.
To boost their chances, the ships could instead aim at dense clusters of stars. The Hyades cluster being the closest at 153 light years. That hopefully let the ships investigate many star systems and even settle in relative vicinity of each other.
*Edit: Oops, turn around, turn around!* *(See Durakken's comment :-)*
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They would start with a *survey*. Look at the much ado about Mars landing sites for an idea of how involved the process is. They won’t be going off into the unknown, picking a direction! They will have targets in mind with *some* preliminary information about them. They will easily know all about the planetary systems involved, including what can be seen from afar about conditions in the target worlds.
They will list out all the candidates that can be reached, and argue at length over which features are important, which risks are unacceptable. These will be **specific worlds** and even colony locations within them, not a rough guess of which direction to set off in!
Most stories written prior to the 1990s missed the fact that we can **see them from here** before going anywhere. Even if that’s more of a stretch with the 500 ly distance, [see this question](https://worldbuilding.stackexchange.com/questions/45756/how-big-can-we-make-a-telescope) and [an article it references](https://en.wikipedia.org/wiki/Astronomical_interferometer#Labeyrie.27s_hypertelescope) where it shows that multiple telescopes placed in the same orbit as the moon (synthetic aperture the half a million miles in radius) can see details 10s of kilometers across on planets **4× farther** than what you are interested in.
Even lacking the ability to take a look first, it would be irresponsible not to send probes before the colony ship.
So, the beginning of your novel won’t be concerning which direction to head off with into the unknown, but will be debate on which sites to target based on knowns and unknowns. They will be scattered around in all directions, and if you want to note that they are not uniformly distributed, take a look at a map on that scale to see of the spiral arm or disk thickness is significant.
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I am writing a story set in a fantasy world, with an atmosphere similar to Earth's. Would it be possibly to have a forest situated near wetlands which create radiation fog at night, which drifts into the forest and doesn't evaporate because of tree cover? This fog could be added to by ground fog from the forest.
EDIT - I should clarify that I would also appreciate a basic explanation as to why it works, meaning that one line answers aren't what I am looking for.
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I think there are a few ways this could be handled.
As suggested by Molot, one easy (probably the easiest) way is to have the forest itself exist at cloud level, as forests on mountains might. The forest area would need to have the right climate balance - not too cold (clouds turn to rain) and not too hot (clouds would lift up higher) - and the geography would have to support it with a large, warm body of water nearby... but I'm sure there are many places on Earth that fit that bill, so it's no stretch for it to be possible.
The more interesting challenge is creating an area that does not use clouds, but instead creates its own fog.
One idea along those lines would perhaps be to have a large reservoir of underground water, and trees which have evolved to "sweat" that water out (for some reason). Effectively, this could create a situation where there is nearly perpetual "dew" everywhere to create fog with - at least during the day. The temperature in that situation could, I think, be pretty bearable. With all that moisture there would also either be a lot of rain in the area, or somewhere pretty nearby (as defined by wind speed). The closer the rain is in the area, the more likely it may be for clouds to be in the area to descend on the forest at night to create fog then as well.
Another idea is perhaps an area where trees have grown relatively tall and with quite dense canopy cover. In that area there are also a number of natural springs and areas of hot ground (very hot natural hot springs may be the easier/more likely solution). If the tree cover is sufficiently dense it could do a decent job of trapping the resulting steam, though admittedly it would also be quite hot.
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It would have to be constantly cool and constantly humid.
a setting example would be a valley that never sees direct sun light and gets a constant feed of moist air blowing off an ocean.
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## Setting
Humans have spent centuries investigating human consciousness, brain physiology, AI, and other technologies. We've finally figured out how to "upload" a "consciousness" (these are quoted because I don't really know what this means at this point).
Personality upload is non-destructive so the original biological entity lives on after the upload.
## The Question
How do we protect the rights of both uploaded and non-uploaded personalities?
Some abuses these entities might face:
* Copying them against their will and using them in roles they do not
want (e.g. as guidance AI in warheads).
* Not permitting them representation in government.
* Them copying themselves to get too much representation in government.
* What legal and moral obligations do the two entities have towards
each other?
Considering that the "you" walking into the personality upload facility is fully aware that it stands a 50% chance of being the biological entity or the uploaded entity when its done, does the law require a 50% split of assets or allow the one walking in to dictate the terms for the two walking out? Perhaps it requires a minimum level of support for each entity.
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**The digital copy would have no rights.**
Certainly not at first. Humanity has not had a good history of [recognizing rights](https://en.wikipedia.org/wiki/Suffrage), even (or [especially](https://en.wikipedia.org/wiki/Corporate_personhood)) of [other humans](https://en.wikipedia.org/wiki/Slavery).
It would take quite a long time before digital-people would be considered people. Even then they would almost certainly be seen as offspring of the flesh-person, not as the same person twice. This would allow them personhood rights, but not entitlement to the possessions/assets of the original (though they may be considered the de facto heir).
The original person might even be legally required to support their copy until it can support itself. For humans in the US that period is defined as 18 years, time would tell what the period of time would be required for spawning a fully developed person.
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Whatever bad thing is in their nature, they must be closely guarded on that front.
The real question is, why in the heck would someone 'upload' a personality with bad traits at all? On the 2nd front, the 'new guy' shouldn't have any of the stuff of the former, unless it has the former's memories, too. This would be so awkward in general as to get the whole thing banned before it could start.
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I've been reading a few articles about Earth-like planets that are both larger AND smaller than Earth itself. But size poses its own problems, thus giving the Earth-like planets their own characteristics.
Two of Earth's crucial features recommended for the possibilities of life are plate tectonics, which move continents and recycle rock; and an ozone layer, which shields the atmosphere from harmful ultraviolet radiation.
Based on what we know at the moment, what are the minimum and maximum size requirements for an Earth-like planet to have both an ozone layer and plate tectonics?
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**It only needs to be big enough to hold on to oxygen.**
The ozone on Earth is generated through the [ozone-oxygen cycle](https://en.wikipedia.org/wiki/Ozone%E2%80%93oxygen_cycle). Any planet with oxygen in its atmosphere and bombardment from ultraviolet radiation will also have ozone. Mercury (0.055 mass of Earth) is large enough to have some oxygen in its atmosphere, though it's tenuous at best. Venus (0.815 mass of Earth) on the other hand has a nice hold on a lot of oxygen and [it also has an ozone layer](http://www.esa.int/Our_Activities/Space_Science/Venus_Express/ESA_finds_that_Venus_has_an_ozone_layer_too).
Tectonic activity is less of a matter of size and more of a matter of how recently the planet formed or if it's experiencing sufficient tidal forces. The Earth will [eventually not have continental drift](https://en.wikipedia.org/wiki/Future_of_the_Earth#Continental_drift). Larger planets will maintain plate tectonics for longer than smaller ones all else being equal, but otherwise size doesn't determine whether a planet will have plate tectonics.
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In some circumstances, the size need not matter.
It is possible for a planet to have plates without having an atmosphere. Have your planet like this, then let oxygen slowly seep onto the planet's surface. Eventually, the planet will develop an ozone layer, and life would become possible, no size requirement needed.
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This is inspired by [a comment by JDługosz](https://worldbuilding.stackexchange.com/questions/21508/equatorial-icecaps-and-polar-jungles-a-fantasy-or-reality#comment55038_21508).
Planets change their angular velocity when they orbit stars because they follow Keplerian orbits with (typically) non-zero eccentricity. The bottom line is that they are not always revolving at the same speed.
Note: The planet should be habitable.
I'd like to apply this to the rotation of a planet. Can I create an arrangement such that it rotates at different speeds at different periods of time? This would mean that some parts would have, say, a 12-hour day, while others would have an 8-hour day or a 14-hour day.
This is not [hard-science](/questions/tagged/hard-science "show questions tagged 'hard-science'"), because I want people to have a bit of fun with this one. But stay realistic!
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In general: the conservation of angular momentum in *orbital* motion leads to Kepler's second law. The velocity and angular motion changes over the course of the orbit. Energy is transferred between kenetic and potential energy, their sum being constant. The body is not stressed except by secondary tidal effects.
The concervation of angular momentum of the body's *rotation* will be a gyroscope: the axis and the rate of spinning around it will remain constant no matter where the body is moved to during its orbit.
Application of a force will cause the axis to precess. This moves the axis in a different direction to the applied force, and the acceleration is felt throughout the body. To apply a torque, pushing one part of the planet differently than another, cannot affect everything equally like free-fall, so stresses will be felt throughout as the acceleration is trasmitted from the place of its application to the rigid body.
Changing the rate of rotation without changing the axis will also necessarily cause stresses and accelleration to be felt. Energy will be lost, so such a process can't simply flow back and forth, but must be powered.
Besides that friction in any real extended body, you need to transfer angular momentum between degrees of freedom in various bodies. The moon is receeding because the tide friction slows the earth and the angular momentum must go somewhere.
How can angular momentum be transferred to/from a body? Only through a force acting non-uniformly on the body. That's hard to do with gravity since the only non-uniformity is secondary differential due to the distance across the body. So, it won't act quickly.
Actually, the Earth *does* change its rotation cyclicly over a year!
[](https://i.stack.imgur.com/QLFMX.png)
If you zoom in, you'll see that the time goes up and down by about 2ms each year, with the real change being a longer slower shift of the average.
This is due to transfer of angular momentum with the atmosphere, which is seasonal and differs in the northern and southern hemispheres. The overall trend is slowing, due to friction.
Some icy moons may have a solid crust over liquid mantle, and undergo *superrotation* as it slips. The tidal stress on Europa for example doesn't match the rotation observed, so it appears to have slipped during the past. Again, this has great friction and isn't something that can continue indefinitely.
If you had part of the body rotating (or holding angular momentum in a more chaotic manner) and transferring that back and forth with the crust, it would be very small or very temporary. You would need a way to add energy in a controlled manner to replace the friction.
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You could do this if you had **two tidally-locked planets that orbited eccentrically around each other**. The entire system would also be rotating in orbit around the star. This would probably need to be an artificial creation, and I am dubious that it would last long in astronomical terms - I suspect the orbits will not be stable.
Obviously not to scale, but consider this horrific MS Paint drawing to get the idea:
[](https://i.stack.imgur.com/FIp4n.png)
The planets would "rotate" faster as they got closest to each other, and slower at the farthest point away. Basically this takes advantage of changing that revolving speed and kind of warps that into subjective rotation.
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In order to understand the physics of this consider something we can actually see - an attractive figure skater. I am sure we have all seen what is effectively dancing on ice. When the young lady starts a spin you will often see her with arms (and leg) stretched out but she will then tuck in tightly and speed right up only to stretch out again to slow down enough to move on to another action.
Likewise on much harder to imagine scales of whole planets and systems energy and matter can change state resulting in different speeds of rotation, amounts of friction, heat and so forth without any actual loss or gain of said energy and matter from or to an outside source.
For example Earth has this odd but life sustaining body of gas arround it against which Earth's movement causes friction. Friction transfers orbital speed into heat although (and this is where my understanding starts to hit my limits) the change is really very small indeed.
It has also been explained to me in the answer to one of my own questions that the moon is very slowly moving away from the earth as the two bodies very slowly approach tidal locking with each other.
So generally there can be change and it can and does happen all the time.
Going back to your non hard science needs we could imagine some super flora that from time to time uncurls massive limbs clean out of the atmosphere. The result would be that the planet would slow down without loss of energy. I can only imagine what effect that would have on weather systems. Probably a reduction in air movement.
Later when it has collected whatever radiation it needed (at the end of the season) or when the winds have flattened the massive fronds back down to the ground the planet would increase in speed again.
Of course at those sorts of scales you would have to hand wave some structural integrity factors like how anything that big could exist without falling apart, etc.
But after the hand wave for the physics of the flora you would have the same result as the attractive lady in the ice skates spinning faster or slower just based on limbs in or out.
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"The bottom line is that they are not always revolving at the same speed." No, not really.
Planets do change their rotation speed, normally as a result of tidal locking. But this is a very, very slow process - millions to billions of years. Keplerian orbits/eccentricity simply has no gross observable effect.
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In my fantasy world everyone has several (three?) magic powers that they're born with, and one of them could be control over plants. About 1/4 to 1/5 of the population will have this. They make the plants grow mostly however they like, though bigger projects will be harder.
**Specific examples:**
Giant trees could be made to grow into houses (think the elven houses in the Inheritance Cycle)
Living boats (self repair!)
Food grown quicker, and out of season
Throwing the seeds on the ground, and making them sprout (perhaps they are vines that can suddenly wrap around the enemy!)
**Limits:**
Plants keep certain characteristics; if a plant has yellow flowers, it keeps having yellow flowers.
Growing a plant too much might kill it
things can't be undone (you can't make a tree absorb a branch you just had it grow)
Significant knowledge of how plants work required
**What are more practical applications of this power? What other limits? What sort of plants would be particularly suited for this? What kinds of rules of biology will I be breaking? Any cool new plant species that could be magically created?**
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Naturally it would depend on how magic itself works within your setting. My own ideas on similar magic have rely on an ability to manipulate something very much like the Force in Star Wars. It is tied to all living things, and while affecting matter, it would be particularly useful when manipulating living things. It could both be used forcefully and more through gentle coercion of natural processes.
One possibility is that the magic user manipulates the water inside the plant such as in the Avatar series. But in order to cause plants to grow and to control that growth, you would have to manipulate the plant on a cellular level and have control over its genetic expression. I would consider looking at some books on cellular biology and particularly at how cells grow and interact with their environment. For example, how when a cell multiples it does so according to cues it gets from nearby cells. It is hard to explain simply but cells react according to chemical cues they get from their neighbours. Obviously you wouldn't have to include all this stuff in your writing but having an understanding of how it works might help you to set limits and create a more convincing magic system.
If the magic user has to understand plants intimately, then maybe you can go into biology (in which case you will need to have a deep understanding). Perhaps the magic user sees/feels/senses the cells and can control their function by overriding the chemical cues. Alternatively, magic itself could have a certain level of awareness and manipulates the plant's cells according to the magic user's will (but still within physical limits).
In terms of breaking biological rules resources would be a major issue. One of the reasons trees don't grow over night is because they spend much of their energy gathering resources. They must collect energy from the sun and carbon from the air to produce sugars. They must gather nitrogen and a wide variety minerals from the soil to produce cells. Without these resources the plant can not grow. Perhaps the magician could stimulate rapid growth briefly, but the plant would very quickly run out of reserves and ultimately die (that could be a risk). As such, the magic user would need a way of providing the extra resources needed (perhaps created magically through some process that can manipulate atoms into new from but then you would likely have issues with energy and radiation but if you were that powerful why would you bother manipulating plants). One possibility is that the magic user has limited power to increase the speed of the plants growth but that the magician's main power is to control genetic expression and cellular functions. For example: you could magically cause a tree to grow into a bridge, but it would still take decades perhaps even centuries. This slow magic approach would work well from a long lived species like Elves but would have limited practical applications for shorter lived species like Humans.
I hope this helps
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An interesting idea might be that, since plants vary in how fragile they are and their uses, people with this ability carry certain types of plants with them in unique ways.
For example, perhaps one such 'plant-controller' or however you want to term them, may find that the flexibility and relative strength of a tough jungle vine mimics rope well and has a variety of uses from the mundane to the combative, as well as defensive. They know they'll be journeying into an area that lacks much plant growth beyond scrub brush and stunted trees in the mountainous crags, so they seek to find a way to bring such a useful plant with them. In the end they decide to bring a moderate belt-pouch or, perhaps more reasonably, a backpack filled with the rich soil of their jungle home in which they transplant such a vine. They then encourage it to grow, wrapping it around them in coils much as one might do with a length of rope, offering some light-weight protection, while also keeping it at hand should it come in handy.
Various iterations of such a practice could come into place with other useful or rare plants, and could also be used for a sort of fashion or status display as well.
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Consider a Banks Orbital, a space station three million kilometers in diameter, rotating once per day for 1g artificial gravity, intermediate in size between a Bishop Ring and a Niven Ring: <https://www.orionsarm.com/eg-article/4845ef5c4ca7c>
I'm trying to figure out what conditions would be like if you were living on such a structure. That is, what the conditions would tend to be like, generated by the physics of the system, in absence of further deliberate modification.
The main factors driving weather on a planet are uneven solar heating by latitude, and Coriolis force. On an orbital, these factors are absent and much weaker respectively.
The accepted answer to this question points out that there will be uneven solar heating between a flat floor and steeply climbing sides: [Prevailing winds on a rotating space habitat](https://worldbuilding.stackexchange.com/questions/119918/prevailing-winds-on-a-rotating-space-habitat)
And the answer to this question discusses the effect of solar tides: [Weather on a mini-ringworld/Banks Orbital](https://worldbuilding.stackexchange.com/questions/8508/weather-on-a-mini-ringworld-banks-orbital)
In summary, apparently the solar tide would drive a high-altitude wind to match the apparent motion of the sun.
I'm now wondering about the tidal effect on the ocean. Suppose there is a single connected ocean running the full circumference of the Orbital. My first guess would be by analogy with a planet, a tidal bulge would be created in the directions toward and away from the sun, producing two high tides per day, just like on a planet.
But is that correct? This object is much larger than a planet. Would six hours be enough time for water to slosh a significant fraction of the circumference?
Conversely, if solar tide produces a steady wind following the apparent motion of the Sun – I don't know what mechanism produces that – but if so, would the same mechanism apply to the ocean, and produce a steady current? If not, why not?
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>
> Would six hours be enough time for water to slosh a significant fraction of the circumference?
>
>
>
Waves travel faster than the individual particles in the medium which the wave is travelling through. This is why you can hear people when they talk to you, but don't get blasted by a jet of air moving at the speed of sound.
Here's a nice visualization of water particle movement in a deep ocean wave:
[](https://i.stack.imgur.com/GtiT8.gif)
Cropped from a larger animation in [this article](https://en.wikipedia.org/wiki/Wind_wave). Though the article is about wind waves, they're just a specific kind of [gravity wave](https://en.wikipedia.org/wiki/Gravity_wave), and tides are another kind.
In deep water, the motion of the particles is fairly negligible. It is only when you reach shallower water and coastlines and the wave is disrupted that you get interesting effects... wind-driven waves get surf, tides generate strong currents, whirlpools, bores, all the rest.
So: 6 hours is fine. The *tide* will roll around the world in that time, but the water does not have to.
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> by analogy with a planet, a tidal bulge would be created in the directions toward and away from the sun, producing two high tides per day, just like on a planet.
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With an orbital, the water is on the *inside* of the curve. This means you don't get tidal bulges where you would on a planet: instead you get tidal "dimples" because gravity and centrifugal effects are pushing water away from the hub of the orbital. I think this will have an effect on the "shape" of the tide (the rates and change of rates of rise and fall) it'll be basically the same as a planetary tide.
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> would the same mechanism apply to the ocean, and produce a steady current? If not, why not?
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[Coriolis effects](https://en.wikipedia.org/wiki/Coriolis_force) can be neglected at the scale of humans in an orbital, but the plates themselves and the structure as a whole is big. Movement of the sea in the direction of rotation of the orbital will tend to push particles outward, towards the sea-bed. Movement against the direction will tend to push particles upwards, towards the hub.
Large currents in a circumferential direction therefore seem likely to break up into horizontal vortices... not necessarily like vast, [deadly whirlpools of doom](https://en.wikipedia.org/wiki/Whirlpool), but present nonetheless, like the horizontal cousin of an [oceanic gyre](https://en.wikipedia.org/wiki/Ocean_gyre) on a planet. This will inhibit large scale current forming.
There's a larger and more complex question here, related to the problem of whether big rotating habitats inevitably form giant rotary winds which destroy everything, or whether you get steady-state smaller scale winds, etc. The exact nature of the coriolis effects can be simulated if you were familiar with computational fluid dynamics, but they're not entirely intuitive. My guess probably isn't much better than yours, and CFD is hard (and the tools are expensive). One day someone might answer these questions properly, but probably not today!
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[Question]
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Some context, right off the bat: I am a mad scientist. This means that evolution has been [defenestrated](https://en.wikipedia.org/wiki/Defenestration); as such, I am not interested in determining what evolutionary pressures might lead to the adoption of such a material as a supportive structure, and nor am I interested in where this thing might find aluminum to keep its bones intact; we're talking mad science and the limits of what's possible within the laws of physics and mortal biology here, not boring old evolution.
I, being a mad scientist, just so happen to be planning on making a creature with aluminum bones; specifically, bones whose primary material is [aluminum oxide](https://en.wikipedia.org/wiki/Aluminium_oxide), rather than carbonated [hydroxyapatite](https://en.wikipedia.org/wiki/Hydroxyapatite).
Now, before we get any further, the question: **What are some structural or biological weaknesses of using aluminum oxide monocrystaline whiskers suspended in a collagen matrix as a material for bones - i.e., why shouldn't I?**
Please note that the core of these bones is plain 'ol [bone marrow](https://en.wikipedia.org/wiki/Bone_marrow). You gotta have that to live if you're Earthly life; I might be a mad scientist, but I'm not a *mad* scientist, y'know?
However, the other parts of these bones - i.e. where there would normally be carbonated hydroxyapatite - are made of aluminum oxide. Here's why that's great:
## [Aluminum oxide has several properties that make it superior to bone as a supportive structure.](https://www.azom.com/properties.aspx?ArticleID=52)
* A [bulk modulus](https://en.wikipedia.org/wiki/Bulk_modulus) - how hard it is to deform - of 137 to 324 gigapascals, as opposed to [bone's average of 18.6 gigapascals](https://pubmed.ncbi.nlm.nih.gov/8429054/).
* A [compressive strength](https://en.wikipedia.org/wiki/Compressive_strength) - how much stress it can withstand before it deforms - of 690 megapascals to 5.5 gigapascals, as opposed to [bone's 170 megapascals](https://en.wikipedia.org/wiki/Bone#:%7E:text=Because%20of%20the%20way%20that,stress%20strength%20(51.6%20MPa).).
* An [endurance limit](https://en.wikipedia.org/wiki/Fatigue_limit) - the maximum strength of a [loading cycle](https://encyclopedia2.thefreedictionary.com/loading+cycles) (a repetitive stress) it can withstand indefinitely - of 59 to 488 megapascals, as opposed to bone's [23 to 30 megapascals](https://www.proquest.com/docview/235100769?pq-origsite=gscholar&fromopenview=true).
* A [hardness](https://en.wikipedia.org/wiki/Hardness) - how difficult it is to be dented or abraded - of [2600-2720 kg/mm/mm](https://www.memsnet.org/material/aluminumoxideal2o3bulk/), as opposed to [bone's low tens range](https://pubmed.ncbi.nlm.nih.gov/31037844/.).
* A [modulus of rupture](https://www.instron.com/en-us/our-company/library/glossary/m/modulus-of-rupture?region=North%20America&lang=en-US) - that is, the maximum amount of stress each fiber of it can withstand right before it fails - of 152 to 800 megapascals. I cannot find a source for bone's modulus of rupture. However, [it is likely to be within the range of 104 to 121 megapascals](https://en.wikipedia.org/wiki/Mechanical_properties_of_biomaterials#Fatigue) - around its [tensile strength](https://en.wikipedia.org/wiki/Ultimate_tensile_strength) - since it is a relatively homogeneous material, and, [according to Wikipedia](https://en.wikipedia.org/wiki/Flexural_strength#Flexural_versus_tensile_strength), this means that its tensile strength is likely comparable to, if potentially less than, its flexural strength. I would [handwave](https://en.wikipedia.org/wiki/Hand-waving#In_literary_criticism) this, since I might be inaccurate here for lack of a source, but I actually have a solution to it below, and, at the very least, bone and aluminum oxide are likely *comparable* in terms of their modului of rupture; aluminum oxide is *probably* stronger.
* A [shear modulus](https://en.wikipedia.org/wiki/Shear_modulus) - i.e. how resistant it is to being deformed sideways - of 88 to 165 gigapascals, as opposed to [bone's stupidly low 51.6 megapascals](https://en.wikipedia.org/wiki/Bone#:%7E:text=Because%20of%20the%20way%20that,stress%20strength%20(51.6%20MPa).).
* A tensile strength (as mentioned above) of 69 to 665 megapascals, as opposed to bone's [101-124 megapascals](https://en.wikipedia.org/wiki/Bone#:%7E:text=Because%20of%20the%20way%20that,stress%20strength%20(51.6%20MPa)). While this could potentially be less than that of bone, [let's assume it isn't](https://en.wikipedia.org/wiki/Hand-waving#In_literary_criticism), since the higher end of aluminum oxide's tensile strength is significantly higher than the high end of bone's.
* A [Young's modulus](https://en.wikipedia.org/wiki/Young%27s_modulus) - how stiff it is against lengthwise force - of 215 to 413 gigapascals, as opposed to bone's ~1 gigapascal; while I do not have a *direct* source for that figure, [the ratio of Young's modulus to the shear modulus of bone is 20:1](https://pubmed.ncbi.nlm.nih.gov/8920251/), and 20 \* [51.6](https://en.wikipedia.org/wiki/Bone#:%7E:text=Because%20of%20the%20way%20that,stress%20strength%20(51.6%20MPa).) = 1,032.
* An [elastic modulus](https://en.wikipedia.org/wiki/Elastic_modulus) - how much force it can take before it non-permanently deforms - of [275 gigapascals (even at a relatively low concentration of 90%, i.e. 10% of it isn't aluminum oxide)](https://www.sonelastic.com/en/fundamentals/tables-of-materials-properties/ceramics.html) as opposed to bone's [34.11 gigapascals](http://shorturl.at/gyK03). Note that the elastic *modulus* is different from the elastic *limit* I mention below; the elastic *modulus* is related to *non-permanent* deformation, whereas the elastic *limit* is related to *permanent* deformation.
Now, as I mentioned further up this post, it might seem that aluminum oxide has a few glaring weaknesses in comparison to bone; it likely has a lesser ductility and elastic limit, and I had to handwave its fracture toughness and Poisson's ratio.
While I cannot find figures on the [elastic limit](https://www.britannica.com/science/elastic-limit) - how much force per unit of area it can withstand without *being permanently deformed* - and [ductility](https://en.wikipedia.org/wiki/Ductility) - how much it can be [elastically deformed](https://www.corrosionpedia.com/definition/2104/elastic-deformation) without *fracturing* - I'm willing to bet that bone's elastic limit is greater than aluminum oxide's elastic limit of 69 to 665 megapascals, and that bone's ductility is greater than aluminum oxide's ductility of of 0.00018.
The only relevant areas in which I know for a fact that it's possible for bone to beat aluminum oxide are [fracture toughness](https://en.wikipedia.org/wiki/Fracture_toughness) - how hard it is for an already-established crack in the substance to grow further - and [Poisson's ratio](https://en.wikipedia.org/wiki/Poisson%27s_ratio) - how much a substance squishes out to the sides when compressed.
* [Cortical bone](https://en.wikipedia.org/wiki/Bone#Cortex) has a fracture toughness of [2 to 12 MPa.m^(-1/2)](https://en.wikipedia.org/wiki/Mechanical_properties_of_biomaterials#Fatigue), whereas aluminum oxide has a fracture toughness of 3.3 to 5 MPa.m^(-1/2). This is enough for a handwave.
* Cortical bone also has a [Poisson's ratio](https://asa.scitation.org/doi/10.1121/1.2935440) of [0.12 to 0.63](https://www.sciencedirect.com/science/article/pii/S002192900600039X#:%7E:text=Few%20studies%20describe%20experimental%20determination,ranged%20between%200.29%20and%200.63.) (if you want to find that particular bit, use control-F to find it, since it's a long source), as opposed to aluminum oxide's 0.21 to 0.33, meaning that aluminum oxide might be squishier. Again, a handwave is completely possible here, but these things will become irrelevant once I implement my solution to aluminum oxide's flexibility and brittleness problems below.
I have a solution to these things, you see; you structure the aluminum oxide bones like [limpet teeth](https://www.bbc.com/news/science-environment-31500883). Limpet teeth contain [monocrystalline whiskers](https://en.wikipedia.org/wiki/Monocrystalline_whisker) of [goethite](https://en.wikipedia.org/wiki/Goethite) - that is, crystals of goethite that are so small that they're flaw-insensitive, meaning that they do not have structural impurities that make larger crystals more susceptible to structural failures. Moreover - and this is the important point - these goethite crystals are embedded in a matrix of [collagen](https://en.wikipedia.org/wiki/Collagen), which allows the teeth of a limpet to be flexible, non-brittle, etc.
In addition to that, these goethite crystals have a low critical fiber length relative to their total, meaning that they're very good at transferring loads to the collagen matrix - in other words, they don't need to be very long to act as good shock absorbers.
My solution to this, therefore, is to suspend crystals/fibers of aluminum oxide within a collagen matrix - much like a limpet's teeth are crystals/fibers of [iron(III) oxide-hydroxide](https://en.wikipedia.org/wiki/Iron(III)_oxide-hydroxide) (goethite) within a collagen matrix - to bring the flexibility of these bones up to a level more comparable to more conventional Earthly life.
All in all, *I'd* say that aluminum oxide monocrystalline whiskers suspended within a collagen matrix are - mechanically speaking, at least - a much better bone than the ones that actually exist in real life, but of course I'd say that, because I came up with 'em. It remains to be seen whether there are *actually* problems with them, which is where you come in:
**What are some structural or biological weaknesses of using aluminum oxide monocrystaline whiskers suspended in a collagen matrix as a material for bones - i.e., why shouldn't I?**
Assume that this creature with aluminum oxide bones is designed to operate under "normal" Earth-standard conditions, on land, at sea level, etc, and that, other than its unique supportive structures, it is essentially a tiger in all other aspects of its biology.
**Good answers will point out a problem with these types of bones, and have a sense of biology, physics, and chemistry at least as strong as my rudimentary ones.**
**Here are three answers that I already have solutions for, *and that I would not like people to answer with*:**
1. Weight. Aluminum oxide is 3.95 grams/cm^3, whereas bone is ~0.92-1.4 grams/cm^3. These bones will be ~2.75-4 times heavier per unit of mass. I know this, and have found a way around it.
2. Availability. Aluminum has to be extracted from substances like [bauxite](https://en.wikipedia.org/wiki/Bauxite), and new metabolic pathways need to be developed to process and handle it. I know this, and have found a way around it.
3. Toxicity. [Aluminum oxide fibers are apparently bad for you](https://wayback.archive-it.org/all/20080522232533/http://www.epa.gov/tri/chemical/chemical%20lists/RY2006ChemicalList.pdf); I personally imagine that they're an inhalant risk, but have no hard sources on that. I don't consider this a problem, for various reasons outside of the scope of this question; i.e. toxic bones are ***awesome***.
I was inspired by [Logan R. Kearsley's answer](https://worldbuilding.stackexchange.com/a/218813/87100) to [a previous question of mine](https://worldbuilding.stackexchange.com/q/218772/87100).
[Answer]
In hydrated environs, aluminium will form preferably [its hydroxide](https://en.wikipedia.org/wiki/Aluminium_hydroxide)
To get it to form aluminium oxide, one needs to calcine it as high as [1100C](https://en.wikipedia.org/wiki/Aluminium_oxide#Production). This is why one will find the crystalline form of [aluminium oxide](https://en.wikipedia.org/wiki/Corundum) mainly in geologies which had some way or another to do with heating and pressure (metamorphic or ultramafic). If you get to volcanic rocks, it will be mainly associated with various forms of silicates (together with other metals).
In the context of the question - I doubt you'll find a biochemistry path able to convince aluminium hydroxides to part with their beloved water and be happy with the oxygen only - you simply need too much energy.
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Probably every reader/viewer of sci-fi/fantasy has at one point encountered the classic bit of trickery: *"The poison wasn't in the drink - it was in the cup!"* - I am imagining a hypothetical reverse situation.
Suppose I am involved in an official ceremony with a visiting dignitary - one whom I would like to assassinate. The ceremony has me provide a drink (not necessarily wine) of which he will partake - making poison an obvious method of assassination. However, due to hard lessons learned from past misfortunes, the form of the ceremony has been changed in the following ways:
* I provide the drink, but both the dignitary and I must partake of it.
* Each of us will provide our own ceremonial cup, so neither of us can tamper with the other's.
This should, it is thought, defeat any attempt of mine to poison the dignitary without also poisoning myself. However, a devious alternative has suggested itself to my mind, and I'm off to see the chemist\*.
I ask the chemist to provide me with:
1. **A poison that I can add to the drink**, which, in lethal dose, is sufficiently undetectable to smell and taste.
2. **An antidote that I can have in my cup**, which is:
* Preferably something I can smear around inside the cup (or added to something I can smear), as opposed to a liquid or powder which could fall out;
* Small enough in quantity that the cup appears empty to a cursory glance, yet of sufficient quantity/potency to neutralize the lethal dose of poison I will drink;
* Guaranteed to dissolve/mix with the drink without too much agitation (no more than 5 seconds of swirling it under my nose and enjoying the bouquet).
**What does my chemist** (\*who is familiar with all the compounds generally known by the early-to-mid 1800s, but knows nothing of modern synthetic chemistry) **suggest to me?**
Some final freedoms/constraints:
* The drink need not be alcoholic; I may choose from a selection that includes anything from 0% to 40% alcohol per volume.
* My cup can be made of metal, wood, glass, pottery, or some artful combination; however, it is only a cup and cannot contain hidden compartments/mechanisms etc.
* *DKNguyen* makes the excellent point that if a poison is sufficiently slow-acting, an antidote could be taken after the ceremony. (Or, for a fast-acting poison, perhaps before.) However, my interest is primarily in the combination of chemicals that could be hidden in the drink/cup in this way.
[Answer]
One of the most famous poisons of all time seems to fit the bill here: **Cyanide**.
Cyanide is neutralised by B12 vitamins, in particular [Hydroxocobalamin](https://en.wikipedia.org/wiki/Hydroxocobalamin), but all are somewhat effective. B12s are found naturally in liver, as well as fermented plant foods like tempeh and in seaweed. The first usage of vitamin B12 (take by eating liver) as a treatment in our world is 1920, but its deficiency had been described in ~1850 as a disease. These are a bit of a stretch for your conditions, but another remedy exists.
Ferric ions are commonly found in rust. They are what's called a competitor for cyanide, meaning that cyanide will try to bind to the iron and to the enzymes, but it won't be able to bind both, so a sufficient concentration of ferric ions will effectively neutralise the cyanide.
The chemist could therefore recommend poisoning the wine with cyanide and use a copper cup to drink. Prior to the ceremony, fill your cup with water containing a high concentration of rust and let it evaporate naturally. The rust in the water will form a reddish coat on the inside of the cup, hidden by the brown copper. This will dissolve into the wine with a few slushes, and neutralize the poison. It will ruin the taste of the wine however
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A few generations back Her Glorious Majesty decreed the creation of the Imperial Rail Ways.
Now, you might immediately think of steam trains and steel rails. Stop that.
See, Her Majesty ruled over a large, mostly flat forest with very few rivers (but excellent groundwater thanks to a system of subsurface caves and aquifers). Moving freight from her more remote dominions to the Capital was tricky (even by road). Other kingdoms move such loads via river or canal barge, but sadly the geography in the heart of the Empire does not support doing this.
The relative abundance of wood and able carpenters meant that laying wooden rails and pulling dedicated trains of wagons with specific gauges (width between the wheels) and flanges or grooves (that keep it on the rail) across some regions was a reasonable solution (plus having a nice flat road with an easy way to pull wagons of supplies doesn't hurt troop movement).
These wooden rails have since become more and more convoluted and complex and entire shunting yards made of nothing but hardwood and polish exist in some cities. Nowadays the rails are maintained and kept clear of debris by the wagon teams and dedicated Imperial carpenters. Power for the trains used to be provided by animals walking in front of the wagon trains but (since they still needed to stop for food and rest) is now provided by Locomotive Galleys.
A Locomotive Galley is, in its simplest form, a [handcar](https://en.wikipedia.org/wiki/Handcar). Handcars are simple contraptions with a reciprocating arm fastened to a wheel and a lever. When the lever is pushed down/pulled up at the right time it pushes the wheel around. Needless to say Locomotive Galleys are more complex. Selectable gearing, a roof and a dedicated crew tender wagon means that an Imperial Locomotive can keep rolling day or night and deliver goods across vast swathes of the empire. They are almost entirely wood, as although metal may be used for certain key components it is hand-crafted and generally hard to replace (no industrial metalworking yet).
The question is just how large these Locomotive Galleys can be built and how long the trains they pull can be before the wood, rope, or men that comprise the train give out.
The technology for bogeys onto which the wheels can be put exists and allows for long locomotives (although I think the driving wheels must be fixed, given the constraints of carpentry). Wooden gearing exists that can be used to down or upshift the torque, though the more force is needed the heavier the wheels will become. If needed a canvas 'bike chain' can be used between two gears. A carpenter will always be present on the train to effect minor repairs and maintain the woodwork if needed, and there is a gratuitous supply of lard available to use as lubricant. No meaningful gradient is expected on the rails.
The engine can be given a starting push by any number of crew at a station but must be capable of continuing to move using only the power of the men inside, and minimal metalwork is preferable (for example an answer using only wooden axles will be preferred over one with metal ones, as long as the friction between axle and locomotive won't cause the whole thing to burst into flame). The technology level is roughly High Middle Ages (1000-1400 AD) and Western European though I'm happy to have some small innovations here and there (for example the Empire uses standardised intermodal shipping crates, a highly unusual concept for medieval times)
Added details: I’m aiming for 100 miles per day, or a sustained 5mph with some station stops. Obviously if I can’t make my trains big enough to carry their own
food/replacement crews this number will have to come down, but I’m more worried about mechanical stresses under constant load than I am high accelerations. You can also assume the rails are made of a harder wood than the locomotive itself, so any failure points will be in the train rather than the rails.
Basically: How big can a train made primarily of wood, rope and sheer bloody mindedness get?
[Answer]
You would not use Rails, but rather flat Tracks. Some people call them Roads.
Metal rails make sense, because the compressive strength of iron/steel is very high, making a rail track with a head width of 3 inches easily capable of supporting 20 tonnes.
Wood, in any form, simply will not be as strong.
So, make your wooden railway a wooden *road*.
If you wish, with a wooden guiderail(s) to keep the train centered.
And yes, wooden wheels are fine, as long as you have something stronger than wood for the axles and bearings. And make your wooden wheels *wide*. Cylinders, not cookies.
Think Fred Flintstone's car, just make a better axle.
Wooden roads are nothing new, there is even a bit of one left out in California.
[](https://i.stack.imgur.com/dsT3k.jpg)
How heavy can your trains get?
Just keep the wheel contact area and loading such that you do not exceed the crush resistance of your rail. For oak, something under 4000PSI is ok.
It would help, *a lot* if your wheel or the road surface could be covered in something resilient. Like vulcanized dried tree sap. Whatchamacallit..... ah, yes, Rubber. :)
To allow a heavier load, just add more axles, or widen your train car's stance. You *are* making the wheel so it contacts the entire surface under axle, after all.
[Answer]
There is really no limit if you design the train in a manner that avoids the two problems associated with wood: the bearing strength of wooden rails & wheels, and the tension strength of the couplings between cars.
The first problem is easily addressed by limiting the weight of any single car. For the second, you do what modern railroads do, and use distributed power units.
You probably think of a conventional train as a locomotive up front pulling a string of cars, but this limits the number of cars to the strength of the coupling between the first car and the locomotive. The solution - which is used in freight trains in the western US (and perhaps elsewhere) - is to distribute several locomotives along the train, at the head, tail, and in the middle: <https://gorail.org/infrastructure/nuts-bolts-why-is-there-an-engine-in-the-middle-of-that-train>
That just leaves you with the problem of frequently replacing rails & wheels as they wear, but that's just a cost & manpower issue.
PS: The wooden gear problem mentioned in a comment to the question could probably be solved by using belt drives. Metal gears aren't all that great for rail use, either, which is why most modern locomotives (if not pure electric) use diesel engines to drive electric motors.
[Answer]
Start with “Power for my people’s trains comes from handcars…”
On Builtworld, anything half-way sensible should go, unless you spend too much time on detail… though of course, “mostly flat” matters more than much of the rest…
On Builtworld, anything more than a few dozen workers should be able to get the job done because so long as the description seems half-way realistic, most readers/viewers will never consider the details. Reality is not needed in Worldbuilding.
In reality, though, Stanford University tells us an average human produces perhaps 100 watts of energy at rest - about the same as a standard light-bulb - can comfortably sustain 3-400 watts while working and while pushing it, perhaps 2,000 watts… most of which goes into running the body, not useful output.
Why not start at 2,000 watts per worker and modify that to suit your scenario, remembering that here in the UK 1,000 watts is the standard power rating of a single element in a domestic electric heater?
Google tells us that 1 kilowatt equates to 1.341 horsepower. For contrast, the average domestic car offers about 120 horsepower, and a diesel-electric locomotive might use around 3,000 hp, or 2,200 kW, and up.
Quora suggests mostly flat track might require 0.5 horsepower per ton, so a 3,000 HP unit could haul 6,000 tons but humps might double the power needed, so halving the load capacity. (I don’t mind whether those are UK, US or Euro tons)
If each worker puts out about 2,000 watts, your Queen Empress's3,000 hp, or 2,200 kW, might need 1,100 workers pumping the handcarts, before you get into reducing the output according to the weight of workers and their handcarts…
Average human body mass, globally, is 136lbs or 62kg. For the wagon weight, why not ask Google or any freight company? Now consider Hollywood’s images of workers pumping handcarts and why so very rarely those handcarts pull trains…
Whoever heard of a any train carrying its own food or replacement crews, let alone a hand-cart train? Why would food and crew not be available at scheduled stations?
How could your hand-carters ever produce “high accelerations”?
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[Question]
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What we call "God" is actually a catch all term for the human consciousness, which we are all apart of. This super consciousness is connected to all human souls, and binds us together on a lower level that we are subconsciously aware of, hence some concept of God existing in all cultures. When we die, our souls fade into this god and become one with it. Everything that has happened or will happen exists all at once in this "God", as it serves as a database for human existence.
There are 5 parts that make up a soul, which are condensed into a stable form and held together by various spiritual components:
1. Raw mana- the life energy of the soul.
2. Ka- seat of a person's Emotions (love, fear, anger, etc)
3. Ba- seat of a person's memories
4. Sed- a person's spiritual I.D. (how the universe identifies and keeps track of them.
5. Un- the connector that binds their soul to their physical body and the physical realm.
By separating the soul into its parts and breaking them down into their originial elements, one can reconstruct their own soul. Through magical means, a person can reincarnate themselves using the soul remains of another. The method is used by less scrupulous mage as a way to cheat death. This glitch in the system essentially wipes a person from the super consciousness, which means that they never could have existed in the first place. This is akin to re-imaging a hard drive, installing a new operating system while completely erasing the old one.
The problem with this is that people are tied with those individuals. Friends, family, loved ones, etc., are all part of a person's memories. Everyone you meet becomes part of your history. Beyond this, certain events happen around or even because of individuals. People become significant to events in some way. The larger those events are, the more people they affect, the more etched they are into our conscious minds.
How can I get around this contradiction?
[Answer]
## It's a super-conscious crisis
The super consciousness will be able to detect erasure in some way, regardless of how you go about it. The only way to "deep erase" would be to steal other people's memories and erase them too. However that still leaves contradictions (erasing a man's wife makes it weird when he magically has a baby one day; the memories of the child are odd without the mother, etc). Furthermore, there is the physical side of things: photographs, clothes, descendants, etc. No matter which way you play it, this is probably better framed as a crisis of some kind for the super-consciousness.
In other words, the super-consciousness figures out that something is wrong, but doesn't necessarily know how to go about solving the problem.
Without access to the Ba or the Mana, the super-consciousness can't re-implement the person's private moments or memories. Maybe it can piece together a rough estimation of the Ka or Sed from other people's memories, but the private ones can't.
This crisis might manifest itself in a number of ways:
* A deep sense of being unwell beginning to emerge in certain populations. This might be an explanation for higher suicide rates, sicknesses, crimes, etc.
* Interacting with the reincarnation causes the memories of that person to haunt the dreams of their loved ones.
* Errors: people have the memories of their loved ones, but when they interact with the reincarnations no one who is still a part of the super-consciousness can see their face or hear their voice (or it's muddled). This might be interpreted by some as the reincarnations being "demons" because of their disfigured appearance and interaction.
* When the super-conscious interacts with the spiritual energy of the reincarnations, it tries to re-incorporate the energy. That could mean anything from sucking the soul out of the person to uncontrollable rage / murderous intent by some people to kill the body so the soul can be re-uinited with the consciousness. Perhaps this even leads to a war between the super-conscious and the reincarnated souls.
* The reincarnated souls end up forming a *second* super-conscious, and although the people of each are unaware, the two consciousnesses can talk and interact as we talk and interact with each other. This might lead to them falling in love, spawning more, fighting, or so on.
[Answer]
If we see the "god" as a database and the individual soul as tables from that database, one can extract the information from the table that is needed (for example the raw mana).
Unless one take all the parts that makes the soul (i suppose) the soul is not erase from the super consciousness.
In common sense, if a mage wants to extend his/her lifespan using the glitch, he/she just have to take the raw mana instead of the other parts (that of course given the case that the mage wants to impersonate other one).
If taking a part of the soul from this "database" stars a domino effect that eliminates the soul, then the consciousness can transport the rest of the data to another database (another dimension or a blocked "noosphere") that can be interacted with if enough powers are exerted.
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[Question]
[
I've begun the laborious (but fun!) process of putting another world together.
Known constraints include:
* Habitable, (super-)Earth-sized, tidally-locked moon to a gas giant; the giant, where visible, is reasonably large in the sky to be rather spectacular a sight;
* All land forms a single supercontinent, exact size to be determined;
* The "day length" on the moon (i.e. its orbital period w.r.t. the gas giant) is about 40 hours long; year length currently undefined;
* We may assume a moderate axial tilt for the gas giant (20-something degrees), and the moon may orbit around the giant's equatorial plane, or any similar plane that would generate "some tilt" with respect to the sun. The moon's own axial tilt is undefined at this point, but likely small; at any rate, the point is that some semblance of seasons should be in place;
* The moon's climate and precise geography is still up in the air, as I'd like to get the astronomy out of the way first;
* Low volcanic activity on the moon. After all, it needs to be a good place to live (and we can also ignore any radiation from the gas giant, save for spectacular auroras);
* Other "fixed", but presumably less relevant details: ~~The star is a "blue straggler" by virtue of me wanting it to be blue~~ (NB: This is likely completely nonsensical, ignore it); the giant may have other moons so that they may occasionally be seen by the inhabitants of our main moon.
I've not figured out how much illumination the moon will get from the sun yet, because I've got a more pressing question: **What would the temperature "under" the gas giant side** (the place where the giant would be seen 90° up in the sky) **be, where the tidal bulge is, ignoring the moon's own climate? Will it tend towards being hot, or will it tend towards being cold?** One can find contradictory information about this, as [this answer](https://worldbuilding.stackexchange.com/a/127448/61202) suggests a large, freezing (or frozen) ocean at that spot; [this answer](https://worldbuilding.stackexchange.com/a/85004/61202), ignoring poles, suggests that the "under-giant" region may be hot instead, as the giant might be "hot". **Does it depend on the giant? Does it even matter at all, or can one go with whatever he wants?** I'd certainly appreciate some concrete information on *this* particular question, as I was unable to find a solid, logical line of reasoning to follow about this one.
I'm personally rather in favour of the side "towards" the giant (or "under", if you're on the moon) being hot rather than cold, but it'd bug me to simply assume this without clear understanding of how and why that would be (and whether it's even possible or likely).
Being "science-based" is important to me (no wizards allowed), but I'd always put the super-hard minutiae away in favour of a "plausible" solution that fits with the concept at hand. In other words, don't worry about maths, solar size and distance, or the time needed for the moon to form in comparison to the sun's lifespan.
**NB:** It's also highly likely that some of the assumptions I've made earlier in this post are wrong; after all, I've only been reading up on tidal locking since yesterday. If that is the case, corrections will be greatly appreciated.
[Answer]
I think that AtmosphericPrisonEscape's answer may be a bit misleading in some respects, as my comments say. For example, there are many tidally locked moons of gas giants in our solar system but only Io is a volcanic hell.
There have been many other questions about possible Earth sized habitable moons of gas giant planets.
I have answered a number of those questions.
Here is a link to a previous question and my answer to that question includes a link to a question and answer which has links to previous questions and answers.
[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)
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/>[2](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3549631/)
[Answer]
Well, if you want to get the astronomy out of the way first, there are more severe problems than if it's hot or cold on your moon, or which colour the gas giant is:
>
> Habitable, (super-)Earth-sized, tidally-locked moon to a gas giant; the giant, where visible, is reasonably large in the sky to be rather spectacular a sight;
>
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>
That's possible.
>
> All land forms a single supercontinent, exact size to be determined;
>
>
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Your planet is going to have increased volcanic activity, and if there is liquid water, plate tectonics should be possible.
>
> The "day length" on the moon (i.e. its orbital period w.r.t. the gas giant) is about 40 hours long; year length currently undefined;
>
>
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There is no year. A tidally locked planet must have its orbital spin vector parallel to its orbital spin vector. Thus, only days exist on your planet. Of course the insolation it recieves would vary together with the gas giant parameters.
>
> We may assume a moderate axial tilt for the gas giant (20-something degrees), and the moon may orbit around the giant's equatorial plane, or any similar plane that would generate "some tilt" with respect to the sun. The moon's own axial tilt is undefined at this point, but likely small; at any rate, the point is that some semblance of seasons should be in place;
>
>
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Well, the tidal bulge from the gas giant's rotation will force the moons orbital spin to be parallel to the gas giant spin (or said differently, it will reduce its orbital inclination to 0 w.r.t. the gas giants equatorial plane). So in the end you must have all three vectors parallel to each other, moon spin, moon orbit angular momentum and gas giant spin.
>
> Low volcanic activity on the moon. After all, it needs to be a good place to live (and we can also ignore any radiation from the gas giant, save for spectacular auroras);
>
>
>
I guess that's alright after all. If you check the [moons of Saturn](https://en.wikipedia.org/wiki/Moons_of_Saturn), you will see that the moons out to 20 planetary radii are easily tidally locked (our moon is even 60 planetary radii away from its host).
The story with Io is in fact that the Laplace-resonance with the other Galilean Moons [pumps eccentricity into its orbit](http://adsabs.harvard.edu/abs/1979Sci...203..892P), which keeps its internal heat dissipation at a strong rate.
>
> Other "fixed", but presumably less relevant details: The star is a "blue straggler" by virtue of me wanting it to be blue; the giant may have other moons so that they may occasionally be seen by the inhabitants of our main moon.
>
>
>
Blue straggler? Did you look that up? The most compelling mechanism for making Blue Stragglers is presently the Roche-Lobe-Overflow in a close-encounter binary system as a result of high star density in globular clusters. No good environment to keep stable planetary orbits. Not to mention that the lifetime of the blue straggler is drastically reduced after it became blue, so there's probably not enough time to evolve complex life.
And whether it is going to be hot or cold is a parameter depending on the distance of the gas giant to the star, the star's luminosity, inclination of the moons orbit around the gas giant and the moons atmosphere.
But you can probably work out a simple [equilibrium temperature](https://en.wikipedia.org/wiki/Planetary_equilibrium_temperature) for your gas giant. The equilibrium temperature of the moon will then be that of the gas giant plusminus some daily variation given by the atmosphere, where the variation will be zero for a very dense atmosphere. In this way you could construct something halfway believable.
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[Question]
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I once show a picture depicticting the idea of an ultimate solar system:
[](https://i.stack.imgur.com/OViCq.jpg)
*[Image Copyright Sean Raymond](https://planetplanet.net/author/snraymond/)*
In this solar system there are 8 planetary orbits, each containing 52 equal-mass, evenly-spaced planets all in the habitable zone.
Now, imagine that in the far far future, humanity has the energy and resources to engineer such a solar system. If we succeded, (assuming that this solar system really is stable and there won't be any catastrophic collisions between the earth and any other planet) how would the sky be different. What I mean is, would the planets that are at the same orbit as Earth or beyond the earth's orbit be visible during the night or the day? And what about the planets that are in front of the Earths orbit, would they be visible during the day? Could they cause minor eclipses when passing in front of the Earth or they wouldn't be visible at all to our eyes.
Also another question about this solar system is, would the Earth be capable of holding it's moon? Would the neighboring planets be too close to the moon when it rotates around the earth, or would there be enough space for the moon's orbit around the earth be unaffected?
Edit:If the planets beyond Earth were visible by night how would they look like to the human eye? Assuming that the Earth was located at the fifth orbit (I'm not exactly sure which of these orbits represents the Earth's orbit, please correct me if it is) how visible would the planets be? Would they seem, like stars like venus or mars, or would they look like smaller versions of the moon?
[Answer]
## Edit
According to AlexP Venus is visible during the day so This changes my answer about day visibility to yes. Sorry for the mistake.
**Visible by Night?**
According to [Wikipedia](https://en.wikipedia.org/wiki/Circumstellar_habitable_zone) the most common estimate for the habitable zone is from 0.95 to 1.37 AU (**A**stronomical **U**nits: average distance between Earth and sun) so we have $6.283 \cdot 10^{10}m$ of room to fit 8 Earths into. This means in most cases the planets will be way closer than even Venus (which is the third most bright object after sun and moon)
So the answer is easily **YES** (every Planet that is in line of sight).
**Visible by Day?**
For this we assume the moon is about 1 cm big for the naked human eye. (If you haven't noticed the moon is visible during the day)
So the moon has a diameter of 3 476 000 m and is 384 400 000 m apart from our earth so the size reduction per meter is about 9 times smaller.
To get the distance to Planets are apart from each other (at least) we simply divide our habitable zone length by 8 for each orbit circle. Which we get 7 853 888 175meters for. Multiplied by our shrinking factor we get a size reduction to the eye of $7.068 \cdot 10^{10}$ which for a planet the size of the earth means it would be around the size of a dust particle. **YES**
**What about planets in the same orbit?**
First we will take a look at the smallest orbit (0.95 AU).
The orbit length can be calculated by this Formula: $Ol = 2\pi \cdot r$ Ol = Orbit length. With this we get a length of $8.9295 \cdot 10^{11}m$ when we divide this by 52 we get the distance between two planets in the same orbit with: $1.717 \cdot 10^{10}m$ which is far grater than the distance between two planets in different orbits but still closer than Venus most of the time so **YES**
**Eclipses?**
Due to their small size there wouldn't be any noticeable effect. So **NO**
**Could earth keep its moon?**
Due to the Planets on other orbits constantly the moons orbit wouldn't be as predictable as it is in our solar system and its orbit would resemble more that of [Hyperion](https://en.wikipedia.org/wiki/Hyperion_(moon)) than that of our current moon. Basically it would wiggle in its orbit.
So the answer is
**YES**
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[Question]
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We have an Earth-like planet except the tropics around the entire planet are covered with small island chains and archipelagos. No landmasses larger than Cuba appear between 35$^\circ$ N and 35$^\circ$ S. Otherwise, island density on this planet matches the size and spacing of the islands in the Caribbean.
On Earth, we observe that hurricanes can pass over large islands like Puerto Rico and Cuba while maintaining strength. On a planet with no large continents near the equator to change the trajectory of the hurricanes, would the paths of the hurricanes stay in the tropics? **If they do stay in the tropics, is there anything to stop them from traveling around the entire planet, picking up energy sufficient to strip vegetation from islands?**
[Answer]
The [Coriolis Effect](https://en.wikipedia.org/wiki/Coriolis_force#Meteorology) will still push any weather system that isn't running dead along the rotational equator, which is every weather system because the rotational equator is a line of no width which nothing can actually be on, further north or south as it gets north or south of said line. Storms will still start in the tropics but their lines will still also run into the higher latitudes just like they do in our world.
With more open water near the equator the tropical oceans will probably be hotter, as will the world on average, (open water has a much lower albedo than land) so a lot *more* storms will form meaning that the tropical archipelago is not going to be a fun place to live, nor are the tropic facing coasts of any southern/northern continents that may exist at higher latitudes. Hypercanes will be a threat at all times of year.
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[Question]
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The article [Why Can't All Animals Be Domesticated?](https://www.livescience.com/33870-domesticated-animals-criteria.html) on Live Science sets out a list of criteria that a species needs to meet in order to be successfully domesticated by humans. In short, that list states that to be successfully domesticated, they...
* cannot be picky eaters
* must reach maturity quickly relative to the human life span
* must be willing to breed in captivity
* must be docile by nature
* cannot have a strong tendency to panic and flee when startled
* must conform to a social hierarchy dominated by strong leadership
Well, it seems to me that [kangaroos](https://en.wikipedia.org/wiki/Kangaroo) meet, or can meet, at least [several](https://en.wikipedia.org/wiki/Kangaroo#Social_and_sexual_behaviour) of those criteria.
**Would it be plausible for [indigenous Australians](https://en.wikipedia.org/wiki/History_of_Indigenous_Australians) to, [circa 1600 A.D.](https://en.wikipedia.org/wiki/History_of_Indigenous_Australians#Before_British_arrival), domesticate, or at least tame and train, kangaroos? What difficulties would they encounter in attempting to do so?**
I imagine keeping the animals for the [meat](https://en.wikipedia.org/wiki/Kangaroo#Meat) is one use. Another, possibly cooler, use would be to use them as beasts of burden, perhaps as messengers, if they can be trained well enough. If you have other ideas, feel free to explore those as well; just make sure you actually answer the question!
[Answer]
While kangaroos meet a lot of the criteria they are failing on a couple of key points.
While kangaroos do congregate in mobs the socials structure is too loose and flexible to a human establish them self as top roo and get the entire mob to follow them. Furthermore this would open the human to regular challenges to his authority from other males. Since these dominance challenges involve face clawing and powerful stomach kicks I don't think humans would be successful at this in the first place.
If the animals were going to be kept for meat they would need to be kept in a fenced enclosure. Kangaroos are talented jumpers and the fences that are normally used to fence in other livestock wouldn't be effective.
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[Question]
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Inspired by the answers to [What can I add to an oxygen/nitrogen atmosphere to make it unpalatable or poisonous to humans, yet stable and breathable to local creatures?](https://worldbuilding.stackexchange.com/q/78786/29), I am building a planet that currently...
* Has an iron core, for the magnetic field to help retain the atmosphere
* Has a surface gravitational acceleration of about 12.2 m/s2, some 25% greater than that of Earth (by virtue of being slightly more massive than Earth as well as somewhat smaller)
* Is covered by 73.9% land and 26.1% oceans (basically the opposite of Earth)
* Has an atmosphere consisting of 67.2% [N2](https://en.wikipedia.org/wiki/Dinitrogen), 27.4% [O2](https://en.wikipedia.org/wiki/Allotropes_of_oxygen#Dioxygen), 4.8% [CO2](https://en.wikipedia.org/wiki/Carbon_dioxide), 0.4% [Ar](https://en.wikipedia.org/wiki/Argon), and 0.2% miscellaneous (which I haven't decided on a complete breakdown as of yet, but which does include 2.4 ppm [As](https://en.wikipedia.org/wiki/Arsenic))
* Has a surface atmospheric pressure of 1930 mbar
* Is highly geologically active, with lots of active volcanoes both on land and under water, as well as active plate tectonics
The planet will have lifeforms not entirely unlike those found on present-day Earth, but obviously not humans as we know them.
Now for the, IMO very much related, questions:
* Will this atmosphere be *stable?* If not, then why not?
+ I don't mind the occasional (or even not so occasional; that's a lot of oxygen) wildfire, but I do mind if half the world goes up in flames the first time there's a meteor strike or volcanic eruption.
* Is the mixture and pressure *reasonable* given the planet? If not, then why not?
* Is there anything about the atmosphere that would pose particular problems to *indigneous* lifeforms? Anything that you can think of which I should keep in mind while designing lifeforms adapted to this atmosphere?
[Answer]
Started as comment and became an answer.
First bit is the volcanic activity may impact your atmosphere. Depending planetary composition, there's a good chance these volcanic events will add a sulfur component to your atmosphere. Minor change at most. Though do remember if your planet lacks plate tectonics and retain this high volcanic activity trait, these volcanoes will start to grow to the size proportions of Olympic Mons on Mars, potentially longer as it grows for billions of years.
Mixture seems reasonable and the components you have chosen can be sequestered away by the planet or released back into the atmosphere. Fluctuations in make-up can be explained by these processes...I'd say you are good.
Last note as a comment to your indigenous creatures. Remember that respiration depends on oxygen partial pressures, not just the ratio of it in the air. At this pressure and concentration, I believe this atmosphere would cause oxygen toxicity issues in humans and most other creatures found on earth. Using past examples, it would appear Gigantism is the natural path to overcome oxygen toxicity. In short, your creatures are going to be over-sized and have a development cycle that includes massive growth early on in it's development to overcome oxygen toxicity issues.
[Answer]
# Partial Pressure
Note that I don't know the $\text{gr/mol}$ of $\text{Others}$ so I tryied to make an average with your actual gases.
$$ \left|
\begin{array}{cc|ccc|c|c}
\text{Gas}&\text{%}&\text{gr/mol}&\text{Mols}&\text{Fractal Mol}&\text{Partial Pressure (kPa)}\\
\text{N}\_{2}&\text{67.20%}&28.01&18.83&\text{62.88%}&121.37\\
\text{O}\_{2}&\text{27.40%}&32.00&8.77&\text{29.29%}&56.53\\
\text{CO}\_{2}&\text{4.80%}&44.01&2.11&\text{0.53%}&13.62\\
\text{Ar}&\text{0.40%}&39.95&0.16&\text{0.06%}&1.03\\
\text{As}&\text{0.024%}&74.92&0.02&\text{0.02%}&0.12\\
\text{Others}&\text{0.18%}&29.94&0.05&\text{0.18%}&0.34\\
\text{Total}&\text{100%}&248.83&29.94&\text{100%}&193
\end{array}
\right| $$
* **Nitrogen (N2): 121.37 kPa**
+ **Nitrogen Narcopsia:** No, don't worry, you don't have nitrogen narcopsia because it's developed under pressures above **240 kPa** and **354 kPa**, and you only have **121.37 kPa of N2**.
* **Oxygen (O2): 56.53 kPa:**
+ **[Oxygen toxicity](https://en.wikipedia.org/wiki/Oxygen_toxicity):** When O2 partial pressure is **above 50 kPa** oxygen become **toxic**. Also you would suffer [hyperoxia](https://en.wikipedia.org/wiki/Hyperoxia).
**Symptoms:**
- Disorientation, breathing problems, vision changes such as myopia.
- Prologed exposures of higher O2 PP or shorter exposure but very higher, can cause oxidative damage to cell membranes, collapse of the alveoli in the lungs, retinal detachment, and seizures.
- A lot more, click in the [link](https://en.wikipedia.org/wiki/Oxygen_toxicity) for more info.
- In [this question](https://worldbuilding.stackexchange.com/a/84125/35041) you can get more information, also you can see symptoms diagram.
* **Carbon dioxide (CO2): 13.62 kPa**
+ **[Hypercapnia](https://en.wikipedia.org/wiki/Hypercapnia) (Carbon dioxide poisoning):** Severe hypercapnia is cause by an increment of **10 kPa CO2** and you have **13.62 kPa**. You will die in hours.
- If you want to see all the symptoms of high CO2 values or a table about CO2% and lethality you can see [the same question of above](https://worldbuilding.stackexchange.com/a/84125/35041).
* **Argon (Ar): 1.03 kPa**
+ Good!, there is a really slow value to be dangerous, but if you want to know more you can see [the same question of above, again](https://worldbuilding.stackexchange.com/a/84125/35041).
* **Arsenic (As): 0.12 kPa:**
+ In [this question](https://worldbuilding.stackexchange.com/a/84458/35041) I said that it's poison but he has 0.93% of As, I your case As is too low. Arsenic toxicity is above **10 μg/m³** and you don't have that, don't worry.
* **Others: 0.34 kPa**
+ It's others, I don't know what it's...
Your animals have to be capable of:
* Support the [respiratory acidosis](https://en.wikipedia.org/wiki/Respiratory_acidosis), they have to be capable of
support high pH levels in blood or have an inner system to reduce the pH.
* Support the [oxygent toxicity](https://en.wikipedia.org/wiki/Oxygen_toxicity), they will have some ability to support the cell membrane damage (e.g: lungs and eyes) and the free radical of oxygen: [ROS](https://en.wikipedia.org/wiki/Reactive_oxygen_species) that destroy the DNA or organels of cells.
Also, take in mind that you wold make the nightmare of all the people, the most fear of ever... ... ... **BIGGER INSECTS!**. Do you think that we already have big spiders, like [this](https://es.wikipedia.org/wiki/Theraphosa_blondi)? Well, I don't want to visit your planet.... In [this answer](https://worldbuilding.stackexchange.com/a/82850/35041) I explain it, insect haven't respiratory system\*, they breath throught their skin so if you make them bigger they won't have enought cm2 of surface per gramme of `insect`, they will suffocate. In your planet there is the double of oxygen in air so insect could be a lot bigger without suffocate.
\* Insect have respyratory system but they don't have lungs or gills, they use other [things](https://en.wikipedia.org/wiki/Insect#Respiratory_system).
# Stability
Sorry, I don't know much of this but I know that **CO2** and **O2** aren't stables.
What this means?
This means that you need a constant flow of them.
* **Oxygen (O2):** Oxygen has the passive ability of [make oxides](https://en.wikipedia.org/wiki/Oxide), this means that if you don't have a source of oxygen, is some millions of years (or less...) all the metals of the surface would be oxides and the oxygen would dissapear of the atmosphere.
My only idea to get a source of oxygen is the [photosyntesis](https://en.wikipedia.org/wiki/Photosynthesis) who make oxygen from carbon dioxide.
* **Carbon dioxide (CO2):** But now we have another problem.
+ Carbon dioxide has the passive ability of combine slowly with the water to make it more acid, well, this is really slow so you don't have problem, but...
+ Photosystesis uses carbon dioxide so you will lose it very quicly, luckly you can us volcanos to get a constant source of CO2.
* **Arsenic (As):** I didn't know about it but from the [Kingledion answer](https://worldbuilding.stackexchange.com/a/80111/35041) I learn it. (You have my upvote).
# Mixture
Mmm, yes, I think it's reasonably, this is almost a personal opinion but I see that possible, **obviously it's only possible if you have a photosystesis (plants) and volcanoes** from me personal opinion.
[Answer]
# The atmosphere should be stable
**Carbon Dioxide**
This Carbon Dioxide/Oxygen ratio should be stable, so long as that ratio is maintained by the carbon cycle on your planet. Having volcanoes to keep re-adding carbon to the atmosphere is definitely good. You will *need* photosynthetic life (or some other oxygen producing surrogate) to keep that free oxygen in the air; otherwise it will quickly end up in the rocks and what have you.
**Arsenic**
[Arsenic](https://en.wikipedia.org/wiki/Arsenic#Compounds) will not hang around in the air. From Wikipedia,
>
> It oxidises readily in air to form arsenic trioxide and water...
>
>
>
[As$\_2$O$\_3$](https://en.wikipedia.org/wiki/Arsenic_trioxide) is in turn hygroscopic and will end up in solution eventually. You would end up with your oceans being a weakly acidic with ionic [arsenites](https://en.wikipedia.org/wiki/Arsenite) in solution.
**Oxygen at high pressure**
Regarding the oxygen level, it was probably [at least 27%](https://en.wikipedia.org/wiki/Atmosphere_of_Earth#/media/File:Sauerstoffgehalt-1000mj2.png) for two periods (of tens of millions of years) in Earth's history, including during much of the Mesozoic.
However, the high pressure does give me some pause. If the pressure is 1.9 times that of Earth, *and* the oxygen concentration is 27%, then the oxygen partial pressure is $$1.9\*\frac{27}{20} = 2.6$$ times that of our Earth, a partial pressure of about 510 mbar. There are claims that air pressure was higher in the Mesozoic, which would render this problem moot by showing that oxygen partial pressure in addition to concentration had been higher in the past. But those claims do not seem legitimate to me, and I'm going to have to [find some hard evidence](https://earthscience.stackexchange.com/questions/10307/is-there-any-evidence-for-higher-air-pressures-in-the-geological-past?noredirect=1#comment20245_10307) before accepting them.
[Equilibrium constants](https://en.wikipedia.org/wiki/Partial_pressure#Equilibrium_constants_of_reactions_involving_gas_mixtures) for gaseous reactions depend on the partial pressure of that gas, so it is partial pressure, not percentage composition that determines if things will spontaneously combust, at least at higher pressures. Figure 5 on page 10 of this [NASA report](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680015284.pdf) shows that flammability decreases for constant oxygen partial pressure as inert gas (N$\_2$) pressure increases, but that this effect stops around 800 mbar. Since the difference between our atmosphere and yours is above that limit, we can expect that flammability will increase as a function of oxygen partial pressure.
Getting exact numbers on what will combust in what oxygen pressures is pretty tough. The linked NASA paper shows that for gaseous fuel air mixtures, 21% oxygen (~230 mbar) is sufficient for flammability and that increasing oxygen partial pressure has almost no effect (page 7).
However, a more reasonable approach to the atmosphere would be to consider that as oxygen concentration increases, oxidation reactions with the various materials of the lithosphere will increase. I think these would be more important than spontaneous combustion reactions. Without any other evidence, I propose that it is logical that there is some 'upper limit' for oxygen partial pressure, at which point the oxidation of atmospheric oxygen with surface minerals outstrips the ability of the biosphere to create that oxygen.
For our planet, that upper limit was probably around 30%, or 300 mbar oxygen. Applying the same to your planet at 1900 mbar would give you an oxygen concentration of about 16%. I suggest that 27% is too high an oxygen partial pressure to develop naturally, and that because of chemical weathering of the lithosphere the oxygen concentration on your planet should not go above 20% at the highest.
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[Question]
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The inhabitants of my Earth-like planet live high up in the atmosphere at ~1500 meters. When they look down, I don't want them to be able to see the ground. I figure the best way to accomplish this is to have cloud cover below them. However, the cloud cover needs to *always* be there. No break, no patches of clear sky. The clouds are always there, and they always cover the *entire* surface of the planet (they can disperse over an ocean if necessary - no one lives above the oceans).
**How can I achieve complete and permanent cloud cover over the ground?**
*Notes:*
* The surface is uninhabited, so you can have whatever you want there, as long as it is natural (aka, no pollution).
* This is a fantasy/medieval setting, so modern gases/pollutants from above are not an option.
* Because my people live *above* the clouds, the lower the clouds the better.
[Answer]
What you want to achieve fits pretty well with the situation on [Venus](https://en.wikipedia.org/wiki/Venus):
>
> Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. [...] Venus's surface is a dry desertscape interspersed with slab-like rocks and is periodically resurfaced by volcanism.
>
>
>
Moreover on Venus (terrestrial standard) life is thought to be possible in the layer above the clouds, where temperatures are lower.
You can obtain the effect you want via what is believed has happened on Venus:
>
> billions of years ago Venus's atmosphere was much more like Earth's than it is now, and that there may have been substantial quantities of liquid water on the surface, but after a period of 600 million to several billion years, a runaway greenhouse effect was caused by the evaporation of that original water, which generated a critical level of greenhouse gases in its atmosphere.
>
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[Question]
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**This question already has answers here**:
[I'm stranded on an alien planet. How can I tell what's good to eat?](/questions/26426/im-stranded-on-an-alien-planet-how-can-i-tell-whats-good-to-eat)
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Closed 7 years ago.
Imagine that humanity made a mining colony at some planet. This planet has its own biosphere.
One of the retired workers decides not to go back to Earth, but instead wants to open up a bistro, so that miners don't need to eat the same stuff every day.
Question is: how does he tell what local delicacies are safe to eat?
* biosphere is protein-oriented, and at least some of it is edible for earthlings - local plant is used to feed chickens, which are than fed to workers, and also as fertilizer for some crops.
* our hero is *not* in a survival situation (so answers from [here](https://worldbuilding.stackexchange.com/questions/26426/im-stranded-on-an-alien-planet-how-can-i-tell-whats-good-to-eat) don't really work). If he needs to take a year or two and use some reasonable money to confirm edibility - he will do so. This also means he is interested in long-term health effects of space food.
* if such research requires some fancy scientific equipment, he probably can get access to it - after all, someone already figured out how to feed chickens with local flora. But what would such equipment need to be?
First obvious answer would be to feed chickens with whatever he finds, and see how they do, but chickens aren't even mammals, so what's safe form them isn't necessarily safe for us.
Edit:
I read the question that mine is supposed to be duplicate of before posting, and in fact I even pointed to it myself. I do not agree that answers there are useful for me. Universal Edibility Test, thorough cooking and sticking to parts of plant that are *likely* to be edible are all methods you are going to use in a survival situation - that is, when you are very likely to die of hunger if you don't. All of them are still very risky.
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## The answers to [this](https://worldbuilding.stackexchange.com/questions/26426/im-stranded-on-an-alien-planet-how-can-i-tell-whats-good-to-eat?noredirect=1&lq=1) question explain the process to test for edibility.
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## *Alternatively*, try an easier approach: Pocket Spectrometers
We already have the technology to scan any object and see its contents without needing a lab (see [here](http://tellspec.com/), [here](https://www.consumerphysics.com/), [here](https://www.indiegogo.com/projects/tellspec-what-s-in-your-food-health--2#/)). No need for future development - we can actually assess, down to the percentages of invidivual molecules, what a potential food item contains.
All this worker has to do is obtain one of these devices (Which aren't super expensive or hard to manufacture), scan everything he wishes to prepare for toxins, and keep what works.
Note that [microbial toxins](https://en.wikipedia.org/wiki/Microbial_toxin) may be a problem if the food is not cooked first; if the worker does not wish to cook then he can use known antibiotics that have been proven to work in the mines (if people get alien infections) or he can simply wait and see what causes problems.
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# Animal testing
Just do what we do on Earth when we want to find out if some new food additive is harmful. Import some animals from Earth and feed it to them. Just as on Earth, the first choice will likely be rats and mice. They don't take much space and mass on the supply transport and they breed very fast. They are mammals so their metabolism isn't too different from ours.
**Warning**: should it turn out that the test animals *can* stomach the local flora, you need to be very, very careful that they don't escape into the wild. Introducing some of our most annoying pests to this planet's ecosystem might cause far more irreparable damage to it than the mining.
# Alternatives to animal testing
There are also [purely lab-based toxicology tests](http://www.the-scientist.com/?articles.view/articleNo/45173/title/Animal-Free-Toxicity-Testing/) which do not require animals. They work on human cell cultures, making them more ethical and in some cases more reliable. It might also be logistically easier for you to import the necessary lab hardware than importing live animals.
But this test method requires skills which the average miner might not possess. Breeding rodents isn't difficult, but preparing human cell cultures under lab conditions is something different. Your miner will either require some background in biochemistry or teach himself that knowledge somehow in order to perform such tests. Also, these tests only tell you if it a substance is *harmful*, not much about if it is *nutritious*. You can't find out if a substance can be digested without a complete digestive system. So you won't get around doing some testing on living subjects eventually. Whether to skip animal testing or not is a matter of how brave you (or your customers) are.
By the way, it might not be too hard to get funding for this project. Whoever pays for the food supply to the colony will be more than eager to throw money at you hoping to reduce the amount of food which needs to be imported. Scientific organizations might also support you because you will collect very valuable data about the planet's ecosystem in the course of your testing.
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This will be a companion question for [How plausible is my monster?](https://worldbuilding.stackexchange.com/questions/51619/how-plausible-is-my-monster). My previous question dealt with a story treatment for a hard science and realistic take on Kaiju/ giant monsters. While that story does feature Kaiju genre elements, it's really more of a western take on a monster with heavy implementation of classic horror tropes. On the flip side of this is a story idea I had along side the above mentioned story around the same time- a full fledged traditional Kaiju story.
Unlike western monsters, Japanese Kaiju are often times god-like in nature and behave more like forces of nature rather than animals. Often times possessing some sort of breath weapon or at least some form of natural (or rather unnatural) directed energy weapons. They more often than not possess hide extremely resilient to conventional weaponry and overall are seemingly impossible abominations whose tamest spit in the face of all known laws of science and physics. As such in this universe we'll likely never have to worry about a Godzilla like organism rising out of the sea and ravaging our cities...but what if one did?
What if an impossibly huge beast crawls out of the ocean and doesn't crumble into a pile of organs and broken bones the moment it takes a step on land? Not only is it walking around just fine but it apparently isn't even fazed by bombs or missiles.
How are its bones not shattering with every step? How is it able to withstand its own internal pressures? How is it able to properly regulate its body temperature?
Any answer to my previous question had to rely on at least speculative science and up to very convincing pseudoscience to work, as giant monsters past a certain size or power level are going to inevitably be implausible. And that's fine, good stories don't need to be realistic as long as they follow their own internal logic.
To make this a little easier I'll give a brief description of the creatures.
1. **The Kaiju range from 100 to 600 feet tall**
2. **They have no set morphology and come in varying shapes and sizes, as a group appearing to be comprised of creatures that vaguely resemble monstrous fish, reptiles, and even mammals and birds**
3. **The Kaiju's skeletons are light weight but are stronger than any metal known to man**
4. **Each Kaiju is powered by an integral organic nuclear engine**
5. **Most Kaiju can fire a particle beam from their mouths**
6. **The Kaiju hide is super tough and resilient**
So my question is this: Without resorting to magic or making them alien constructs, what sort of [Applied Phlebotinum](http://tvtropes.org/pmwiki/pmwiki.php/Main/AppliedPhlebotinum) can I add to my story to convincingly explain away the above attributes and the common problems a Kaiju would realistically face in real life?
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This pushes the limits of plausible. Eliminating magic in the strictest sense for starters. That leaves alien constructs or super-science (often called 'magic' in this neck of the woods). The OP did try to remove alien constructs, but that doesn't seem possible.
The Kaiju could be teramorphic cyborgs (that's monstrous or monster-shaped cyborgs in quasi-medical jargon), but that leaves as an open question who or what made them.
The Kaiju could be giant robots shaped like monsters. This would take care of the issues of their material strength and powered systems as well as their wide range of morphology. Same problem about who made the Kaiju robots. I will leave this as an exercise for the readers and the OP.
The Kaiju could be lifeforms from an alternative universe where the physical laws are different and environmental conditions more than verge on the nuclear-energetic and permitting the evolution of nuclear-powered, particle-beam zapping mouth parts. Gravity is higher there. The Kaiju are composed of exotic, ultrastrong biological materials.They have nuclear metabolisms. Evolution there favours megafauna. For ecological and geographical reasons, their home territory will be most likely a super-continent.
Presumably somebody carelessly left a wormhole open with one mouth under a nearby ocean. The Kaiju sensing pastures greener have ambled through to wreak urban renewal havoc on our world. Basically it's ecological expansion into new territory.
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Well, with my own kaijuverse, my kaiju (which I am calling behemoths) are giant biologically engineered creations of a prehistoric extraterrestrial civilization, which made them by modifying local lifeforms, strengthening their bones and muscles until they are able to support their own weight. Several of my creatures are genetic chimeras as well, as they combined features from several organisms into one being.
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**Glitch in the matrix.**
These things are impossible in our reality. They become possible only when reality breaks down. Such stable glitches can manifest in a number of different ways, but a particular interaction between glitch and reality self repair / damage control mechanism can create a phenomenon that our sensory apparatus interprets as a giant creature. The reality repair mechanisms shore things up around the glitch and make it somewhat consistent, even though the rules of physics are inconsistent and don't apply.
If the repair mechanisms intrinsic to our reality are unable to resolve the glitch, only contain it, then there might only be one way to dispel the problem permanently. Merge it with another glitch.
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# Lamarckian evolution of spiritual beings
So, [this guy](https://author.today/u/sergeyplotnikov) used a setting where ayakashi (Japanese ghosts) exist. Now, and that is completely his idea, not mine, he got them the [Lamarckian evolution](https://en.wikipedia.org/wiki/Jean-Baptiste_Lamarck), not the Darwin's one. Basically, an individual species can evolve. It's a *personal* evolution where ayakashi get more powerful, grow themselves human-like intellect, learn few tricks up their sleave, get again more powerful, etc. For boosting, add inter-species cannibalism, ayakashi eat other ayakashi.
Now, for certain factors (such as presence of ghost/demon slayers) limit the *mass* evolution to the cap on the surface. But not in the ocean. There is enough food in form of lower-level ayakashi. So, nothing hinders them to grow to excess power levels and (as they are not really limited by physics) excess sizes. You got you your kajus!
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Now, let's check your criteria.
1. *The Kaiju range from 100 to 600 feet tall.* -- check, they can grow as large as the f... they want and/or can sustain;
2. *They have no set morphology and come in varying shapes and sizes, as a group appearing to be comprised of creatures that vaguely resemble monstrous fish, reptiles, and even mammals and birds.* -- yep, ghosts with some kind of initial prototype, but easily changed to fit the purpose;
3. *The Kaiju's skeletons are light weight but are stronger than any metal known to man.* -- somewhat, nobody knows what's inside, as they are not fully physical;
4. *Each Kaiju is powered by an integral organic nuclear engine.* -- just plain no, unless you count magic as nuclear engine; but hey! It's possible to rationally explain magic... somewhat;
5. *Most Kaiju can fire a particle beam from their mouths.* -- some kind of a distant attack seems reasonable for the eternal fight of ayakashi for survival, so why not?
6. *The Kaiju hide is super tough and resilient.* -- they are not fully physical, so might well be.
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A nice bonus (again, not mine) is a "Kaiju link": if someone/something strong enough gets close enough to the ocean to lure something *large* from inside, that very being might lure up something even bigger, and so on -- the "bigger fish" [style](https://imgflip.com/memetemplate/306969297/Bigger-Fish) -- up to a Kaiju. *That's* why they surface up!
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What I recommend is that you search information about the largest creatures that have inhabited the earth, especially the sauropods.
Use that knowledge and adapt it to your kaijus
Hope it helps.
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Back in highschool I had a teacher who was adamant that rocks were alive; stating things like "They reproduce when you break them". They might have been a bit on the "outthere" side, but I was thinking recently: How could a rock be considered alive?
In my story, there is a particular organism called a gemite bloom. It is a crystalline flower-like life-form. As I have it planned, it works very much like a plant with a few differences. At the start of it's life cycle it looks like a crystal seed, with a small organic core at the center. You can plant the seed and it will absorb nutrients through the soil, through microscopic pores in the crystal. The organic core will begin to grow overtime, growing tendrils that stretch and start to drill through the crystal. As it reaches the outside of the crystal the tendrils start to secrete a substance that hardens and becomes an extension of the crystal.
This process repeats until the tendrils reach up through the soil and reach sunlight. The center organ will then begin to shift upwards, dissolving the crystal and replacing it as it moves to reach the sunlight. It undertakes a photosynthesis procedure (lots of light can easily pass through the crystal exterior) and begins to develop a stem to reach higher, a core support tendril and eventually a bud. The bud then grows larger and the central organ takes hold in the center, creating hundreds of tiny very efficient photosynthesis filaments that extend through the bud. When ready it blooms, opening it's petals and gathering even more sunlight. Eventually the core organ begins to subdivide and new "seeds" are formed which then, after growing to a self sustaining side, drop out of the bloom and become their own organism. Thus what is left is a flower-like organism that is composed of a very beautiful, but brittle crystal and living core.
EDIT: I should add that if you stripped the crystal from the organism, it will not survive, it needs it for protection and in the case of the filiments, they are so closely linked that it's nearly impossible to seperate them. In case that helps.
So, with that process somewhat explained (I wish I could draw well, I feel pictures might help a bit), I have a few questions.
A) Is this feasible as a life-cycle?
B) Would this be considered a "plant-like rock", or "rock-like plant"?
If "rock-like plant" to B: C) Is it possible, by definition, to have a "living rock"?
D) Is it possible to extend this type life creation to a crystal Golem that develops a consciousness and is self-sustaining by photosynthesis. (Cause I don't think it could really live by eating "non-living" rocks, but maybe I'm wrong.)
EDIT:
I'm looking for a mostly scientifically backed answer, but since this takes place in a world with magic I've included the magic tag. Magic can be used to bridge the gaps that science doesn't have plausible stance for, but refrain from hand-waving if possible. (Not that I have, haha.)
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To start with: We've already got several species of [rock like plant](https://en.wikipedia.org/wiki/Lithops), somewhat handily called 'living rock plants'.
But your species seems to be somewhat more like a [caddisfly larvae](https://en.wikipedia.org/wiki/Caddisfly), encasing itself in a hard, rocklike material in order to protect it's squishy innards. Anyhow, onto your questions:
A: The biggest issue here is resources and logistics. The environment in which these 'plants' grow is going to have to be very high in silicates that are compatible with being turned to crystal, much like how our plants can only grow when given a decent supply of carbon. This is complicated by the fact that they also need a source of food for their innards. If they're a carbon based lifeform wrapped in a silicate shell then they're going to need two distinct resource sets, and two methods for managing the different resources. If they're a silicate lifeform then they pretty much fulfil the criteria of 'living rock' all on their own. :D
B: Rock like (or covered) plant. Unless it's silicon based biology, in which case: plant based rock.
C: By definition? If we discover a species that uses anything other than carbon as the fundamental building block of it's existence then we're going to have to look at redefining a few things, so I'm sure we can work 'living rock' in there somewhere!
D: No. Not really. Unless this golem lives in a crazy hot world it's not going to be able to garner enough energy through photosynthesis alone to be able to cart around a load of rock. It could evolve into the equivalent of a herbivore, however, and feed on the 'plantlife' around it, using both the resources from the tasty innards for energy and the minerals from the outsides to repair it's own hide (which would be constantly wearing and cracking at the joints). If you're going down the path of silicate only lifeforms then eating 'non-living' rocks would be somewhat akin to a human eating a lump of coal. Technically it's got the right materials, but they're not in any kind of a useful structure that their bodies can metabolise. They've got to wait for the next gemtato harvest.
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I have got a big rotating space station (radius is 5 km and length is 30 km) which provides its occupants the luxury of full terran gravity and atmosphere. The biggest part of the cylinder's inner surface is covered by forest (which provides us with oxygen), small lakes, fields and farmland. Now, I have decided to get into the wool and mutton business. A transport ship with 50 [Rhön sheep](http://www.ansi.okstate.edu/breeds/sheep/rhoenschaf/), each originating from a different herd, 45 of them being female and 5 being male, all 2 to 3 years old, has just arrived. The sheep were separated into 5 herds of 9 female sheep and 1 male and marked using colors to control breeding.
My questions are:
* Since there are no seasons on a space station, can my sheep breed all year round? I would like to do it herd-wise, meaning that one herd will be lambing in January and February, one in march and April and so on.
* Do my sheep need to adapt to the Coriolis effect? Will they behave strangely and stop giving milk/breeding when they notice that they actually are in a rotating cylinder?
* What is actually the minimum size of a sheep herd for genetic sustainability? Do I have to let the 5 herds interbreed?
* What adaptions to the environment of a space station will the sheep produce after thousands of years?
* I have chosen Rhön sheep because they are adapted to bad weather and cold environments; they also are able of using the sparse vegetation that will probably be available in my space station before a full biological system is worked out. Is any other type of sheep better? Should I use multiple different sheep breeds?
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* With same season year round and no predators, the sheep are expected to breed all times non-stop. You would have to separate the males from females at times when you don't want them to breed.
* Sheep aren't space scientists and they won't find or figure that out. You can stop worrying about it.
* No idea on that. You should read about cheetahs for that context as they have the least genetic diversity of all mammalian animals.
* Too speculative. Too broad, too. You might want to import a fresh stock from home planet if the later generations of sheep start showing adverse effects. Or ... you might want to save some tissues of the original sheep for cloning in case no further shipments are available.
* The best idea is to first import several types of sheep and test them for compatibility. Then select one breed that looks most suitable AND is large enough to provide enough quantities of meat and wool to cope for the herding effort.
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Assuming high lift costs I must object to your plan.
You should bring 50 female sheep from 50 separate sources. There's no good reason to boost a ram, for the same lift cost you can boost semen from thousands of different sheep--and there's the solution to your genetic diversity issue also.
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I have my own theories, but I'ld like to hear other oppinions about how this kind of scenario could turn out. This is one part of a story I'm developing.
Setting: We are talking about a medieval / fantasy setting around the year 1300-1600.
At some point in the history of this world, it’s inhabitants start to experience something strange: They dream about their own future - all at the same time. This is a global effect and affects all people who were sleeping (and able to dream) during that exact moment where this strange event was triggered. Everyone dreams about the exact same period of time and the dream feels real and detailed. If someone would die during that period of time, they’ld suddenly wake up like after a horrible nightmare - if not, they’ll continue to sleep normally but still have quite a good memory about the dream when they wake up later.
Some will quickly realize that the dream wasn’t just a dream, but instead an accurate depiction of what would happen if they didn’t have that dream. In other words: The dream depicted the future exactly, but since many people now know their own future they can act accordingly and basically change it instantly. Since this causes most dreams to not match reality after a few weeks, some might forget about it. Who knows.
But then, a few months later - it happens again. This time, it’s at 13:11, and they only dream 3 years of their future. But these global precognitive dreams keep happening in irregular (and sometimes quite short) intervals. In fact, in some rare occasions, they even dream about having such a precognitive dream! People start to notice and talk about it. Some will probably panic - others will make use of those informations.
I’m not sure if I explained it well enough, so a few pointers:
* Every global trigger of this event has an apparently random interval (there is a reason for the triggering, but that’s out of topic). Let’s assume that it can happen at any time of the day (0:00 until 23:59) and that the intervals range between a few days to a few years.
* Every person asleep and able to dream during a triggering, will have such a precognitive dream. This basically means that during such an event, one side of the world is affected more than the other.
* People who are awake during that event are completly unaffected.
* Every person’s dream has the same ‘length’. They all dream 20 years of their lives, or 15 years - or maybe just 2 days. Each trigger has a random duration (with tendency to multiple decades), but that duration then is the same for everyone dreaming - even if suddenly woken up inbetween.
* People who dream about their own death will wake up right afterwards, as if they had a horrible nightmare. They'll remember everything up to the point where they pass out, basically. Otherwise, people who don't die will continue to sleep normally. Dying doesn't have any real influence besides the way those people tend to wake up (it's probably quite a bit more traumatizing)
* The precognitions are absolutely accurate. But just the fact that some people dreamt about it already changes the future by itself. If no one would’ve had those dreams, everything would happen exactly as predicted.
* Those dreams happen instantly, as soon as the event was triggered. Interrupting a person that is just having that dream is basically impossible.
* The dreams are a reflection of "what would have happened". It's not a dream in the common sense, where it might can be influenced from outside or things like that. It's basically just a taped version of the future displayed as dream.
* **Edit:** The dream feels realistic, but the person will not inherit any mental illness caused by future events. The dream itself can still be horrible / shocking enough to scar the person though, if someone is that unlucky. Here it works pretty much like our own dreams: The worst you can have is a horrible, realistic nightmare. I'm not sure how this kind of thing can affect a person's mind.
* They can have precognitive dreams about precognitive dreaming. But this would remain quite rare and can be ignored for this question.
**Theese dreams continue to happen and don’t have any apparent end. The intervals are not predictable. How could the people in such a world react and develop?**
As sidenotes, my own thoughts about this kind of scenario:
Mass hysteria/panic? Depending on religious aspects?
I think technological advancements would be much, much faster, since an inventor (or a customer) knows the tool already and can re-invent it ahead of time.
Ethics/Morale would be affected. Now a murderer in the future, is known in the past. A man/woman who is unfaithful would have to pay the price before even doing it. A conflict between two friends/family members/parties would alredy affect things in the past, etc.
Ambitions might change. Someone who realizes that they don't want to meet the same end try to find other means of living.
All the newborn children in those dreams basically will never exist (?), since the exact sitations/details change.
**Edit:** Added another point about mental scars / effects.
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I did what I could to answer some of your questions, but I don't think I addressed every aspect of the issue. Let me know if there's anything in particular I missed or should elaborate on, or feel free to write your own answer.
**Personal Effects** -
This question reminds me a lot of [this one](https://worldbuilding.stackexchange.com/questions/18051/tomorrow-is-groundhog-day-for-everyone-how-does-society-respond) about a worldwide Groundhog Day phenomenon, in that a lot of what people do every day could turn out to be useless. For instance, if you work for twenty years at a job you hate before finally going mad with boredom, you can rest easy knowing that at least you provided for your family-- until you wake up and realize it was all a dream. Just like in the answers to the aforementioned question, this society would start valuing knowledge far more than physical objects. If you read a book in a dream, you should still remember what you read when you wake up, even if you don't have the physical copy. Thus, there should be a greater demand for teachers and storytellers, and various forms of short-lived entertainment, rather than things like decorations that only pay off if you get to keep them around.
**Time Travel** - Like you've mentioned, the people who've had these dreams have seen the future, and thus once they wake up they have effectively traveled into the past. On a personal level, these people will try to avoid mistakes they made and take advantage of opportunities they missed. On a larger-scale level, these people will be paid to accurately predict things. The accuracy of these predictions will vary: things like the weather are going to be the same no matter what anyone does differently, while the actions of people will change based on two factors: **1)** - how long the dream lasted, and **2)** - how many people were asleep. If only one guy had the dream, everything should happen as he remembered it, but if half the world had it, things will change almost immediately. However, if the dream lasted a sufficiently long time, there will be a greater length of time where things happen the same, since no one will be able to accurately remember what happened back then. Bottom line is that in most cases, the things you remember are going to stop being useful to you at some point; this could lead to some very sad scenarios, such as a guy who knows he died in the dream, but doesn't know if the world has changed enough this time to avoid it, or someone who found their soul mate in the dream, but cannot find them in the real world because things have changed too much. These problems are compounded by the next point:
**Countermeasures** - People like to know what everyone else is going to do, but no one likes when other people know what they will do. Thus, when a dream event occurs, it will be the top priority of many people to do the exact opposite of what they would have done. Armies would throw out all of their plans and start fresh, merchants will take a different route through the forest to avoid bandits, passwords and locks across the world will be changed. This is going to severely limit the abilities of your precogs, *but only if someone finds out about the dream event.* People who can afford it will have a series of 'sleepers' whose only job is to be asleep around the clock (in shifts) and inform whoever's paying them whenever there is a dream event. During their waking hours, these sleepers may actually be sleeper agents, working for the enemy, gathering data to be used when a dream event occurs. When a dream event *does* occur, it will be a race to take advantage of it before the enemy does.
**Religion** - There are a few religious problems here, but I don't think they'll matter much. There is the issue of 'why?' but religions have always been able to avoid those questions by making up answers or attributing it to some sort of 'divine mystery'. People may think these dream events are meant to help the faithful, or push humanity in the right direction, or something like that.
The bigger problem is that someone has recorded the future; this has enormous repercussions on the notions of free will, destiny, and such. But again, religions usually have answers to these sorts of things. Either there is no free will (as I recall, this is what some sects of Protestantism argued), or God is just powerful enough to create 'what if' scenarios, but the fact that people change the future after dreaming it means that we *do* have free will.
**Ethics** - As you said, people may learn about future crimes, and wish to apply punishment early. But I think we sort of do this already, just with incomplete information. If someone has committed crimes, people suspect they will do them again. If you commit a crime in the future, people suspect you will do it again. But since the future *can* be altered, these precognitive crimes are just like past ones: the people guilty of them can change, can be saved, can see the error of their ways, etc. Plus, see the 'Countermeasures' section for why most of the things these people did probably won't happen now.
In summary, I think the overall effect of this is that people would live more in the moment, and be much more willing to change. You can't really make long-term plans if there's a good possibility you're in a dream. Knowledge will take precedence over physical possessions, and flexibility will take precedence over following a set plan. As a result of this, like you said, science and technology should improve at a greater rate. However, larger, more long-term things like architecture and government might suffer. And, for the most part, people will adjust, so these changes shouldn't end up making too much of a difference.
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Your justice system may have to cope with dream-only violence if and when the harm is psychological. Someone may pre-commit to abducting and torturing the heir to the throne but then after the next dreaming cycle in which they remember carrying out their plans they cancel them.
The heir wakes up having just experienced horrible endless torture and ends up a wreck. You meanwhile cancel all plans to do it. You never actually carry out the act but the heir is now out of the way.
If your justice system doesn't punish pre-crime then you throw up your hands and say that you've seen the error of your ways and of course would never do that in this timeline.
There's going to be a lot of trauma in your world. Everyone who burns to death in an accident is going to have memories like someone who survived horrible burns in an accident.
And since everyone keeps trying out alternative futures a huge portion of the population is going to get to randomly experience horrible trauma.
Indeed some people are going to try to cut down on hours asleep for fear of more such events.
To build on DaaaahWhoosh's answer, people are going to intentionally seed false information in the expectation of more dreams.
Loss of dream children is going to be particularly hard. Imagine living through 20 years of raising a child, seeing grandchildren but then you wake up. They're effectively dead and you lost them more thoroughly than mere death. People are going to be grieving for lost children a lot. I can imagine parents waking up together, realizing they were in a dream and bursting into tears because Bobby is gone just as truly as if he was hit by a bus. I can imagine people fearing close connections for fear that they'll wake up at any moment like the last few times.
On the bright side you're going to have people waking up able to play the flute like someone who's spent 20 years practicing. People with terrible regrets are going to hope that they'll get to wake up to try again like the other times.
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I'm currently world building for a novel of mine that I am currently writing.
It is [steampunk](http://en.wikipedia.org/wiki/Steampunk)-themed so the technology I am going to use is steam based.
Let's start this at the beginning so you might understand.
At the beginning we have a mineral called Beatrice. When refined and ground into fine dust and mixed with water then heated to the boiling point, it creates an [anti-gravity](http://en.wikipedia.org/wiki/Anti-gravity) effect which I call the *Beatrice Effect*.
I want to be able to explain how this works to my readers in a very easy-to-understand way. One way to do that is to understand how anti-gravity works apart from making a 1,323,000 ton super carrier/assault carrier float mid air. How does it affect the ship and how can it have various applications in a magic-steampunk driven world?
How can an anti-gravity effect also be applied for carrier/land-borne aircrafts and as a weapon of (controlled) mass destruction?
For reference:
1 kilo of 90% pure Beatrice is able to make a 1,200 ton frigate afloat for a year.
[Answer]
Antigravitic MacGuffins are some of my favorites. And yours is the mother of all overpowered Antigravitic drives. We'll ignore the most obvious issues (if it cuts off gravity, it cuts off solar and galactic gravity as well and quickly diverges from the planet and the solar system) because airborne super-heavy battleships are just so much **fun**.
Now, the idea of a 1.3 million ton superfloating plaform is impressive, since over in 1945, after 6 years of ramping up war materiel production, the entire US economy had the capacity to produce about 80 million tons of steel per year, only a fraction of which would be of the thickness required for ship plating. But with a 1.2 million : 1 lift ratio, new miracles become possible. However (assuming for sanity's sake that the effect is limited for the most part to Earth's gravity or that engineering corrections are put in place to account for any deviations) that still leaves the issue of **moving 1.3 million tons of stuff horizontally**. By comparison, the superheavy battleship Yamato (74,000 tons) or US Supercarriers (100,000 tons) get to push against much denser water.
The lift is being provided by firing up (or cooling down) different numbers of these heated MacGuffin-Beatrice tanks, which can be placed behind thick, thick plating, making what we think of as anti-aircraft ground fire about as dangerous to them as fireflies. Since we're steampunk, there are no guided or nuclear rockets, so these are the ultimate 'tanks', in the sense that they don't care about terrain, can take a lot of heat, and can generally be taken out mostly by other 'tanks'
Horizontal movement, as alluded earlier, is slightly more problematic. I'm assuming you have no jet engines, so exposed propellers would make an obvious choice if trying to disable such behemoths. This will quickly persuade military aircraft builders to place the propellers at the top of the structure, relatively safe from direct ground fire, or, if possible, down well-protected (sealable?) shafts.
Now with the ultra-thick plating on all sides, it's starting to sound less and less like an aircraft carrier (since what can piddly little fighters do to 2 meters of armor plating), and more like a Yamato-style superbattleship. To get through thick armor and pierce through to those propellers and MacGuffin steamtanks, you need **big guns**. Really, really big guns. And **range**, so that *their* big guns don't get to hurt you. Guess what helps with range (also with hitting those exposed top-propellers)? Altitude. This will quickly become a game of who can go (and stay) highest for longest. Imagine a ship with a battery of a dozen Doras or [Heavy Gustavs](https://en.wikipedia.org/wiki/Schwerer_Gustav) guns trading 7 ton shells at a range of 50km from 10km up in the sky with an enemy ship.
[](https://i.stack.imgur.com/JjG4A.jpg)
Your airmen will need to wear oxygen tanks during battle, pressure suits and very warm clothes or die instantly from asphyxiation. Obviously you can't maintain a 10 km unpressurized altitude for too long with a human crew, (and steampunk has no radars, right?) so sneaking up on a low-hanging (mere 2000m) ship through stormclouds or from sunblind spots will be a favored tactic. The ceiling on propeller craft seems to be around 17 km. Perhaps the first combatant to successfully pressurize their superheavy ships and develop jet or rocket engines could manage horizontal movement at altitudes of 20 km and wreak havoc on the fools below.
See: The American Steel Industry, 1850-1970: A Geographical Interpretation, by Kenneth Warren
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[Question]
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Are there any reasonably plausible alternatives to the process used by our plants on earth (Carbon Dioxide, Chlorophyll, Oxygen) around which an ecosystem could be built in a planet with a completely different atmosphere? Would every planet with life on it need to have a carbon+oxygen based life-cycle or are there any viable alternatives?
To be clear, I'm talking about a Sunlight-powered ecosystem but one where the plants do not use or produce CO2, O2, or both.
If there are any alternatives then are we able to make any guesses as to the appearance or other properties of the plants that might live in that atmosphere?
[Answer]
Yes, there's an alternative.
Plants using chlorophyll must, to the best of my knowledge, take in CO2 and put out oxygen. So chlorophyll is a no-no. Fortunately, not all [photoautotrophs](https://en.wikipedia.org/wiki/Phototroph#Photoautotroph) use chlorophyll. A select few use a substance called [bacteriochlorophyll](https://en.wikipedia.org/wiki/Bacteriochlorophyll) (see also [here](https://web.archive.org/web/20150101034555/http://www.bio.ku.dk:80/nuf/research/bchlc.htm)). Here's its structure:
[](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Bacteriochlorophyll_a.mol.svg/600px-Bacteriochlorophyll_a.mol.svg.png)
Atoms (vertices) not labeled are carbon atoms.
Bacteriochlorophyll is found in, not surprisingly, bacteria! Certain "green bacteria" contain organelles called [chlorosomes](https://web.archive.org/web/20150515060317/http://www.bio.ku.dk:80/nuf/research/chlorosome.htm). The process looks like this:
[](https://upload.wikimedia.org/wikipedia/en/1/1e/Chlorosome.PNG)
Some of that can be understood from the image; [more detail](https://en.wikipedia.org/wiki/Chlorosome) sheds some light on it (pun very much intended).
Much better information can be found [here](https://phototroph.blogspot.com/2006/12/chlorosomes.html). The photosynthetic process involving bacteriochloropyll can be summarized as:
$$\text{carotenoid} \to \text{Bchl c}\_{\text{chlorosome}} \to \text{Bchl a}\_{\text{baseplate}} \to \text{Bchl a}\_{\text{antenna}} \to \text{Bchl}\_{\text{reaction center}}$$
What does this mean? Check out this image:
[](https://photos1.blogger.com/blogger/4566/894/1600/chlorosome-gr-bact.jpg)
Energy travels first to "cylindrical aggregates of Bchl c and carotenoids" (1), from the carotenoid to the Bchl chlorosome. Then it goes to the baseplate (2) of Bchl. From there, it goes to the antenna proteins (5) and finally the reaction center (6). There is Bchl in both the antenna proteins and the reaction center. Does this make the second image from the top a bit clearer?
Processes using bacteriochlorophyll does not use carbon dioxide, as normal photosynthesis does.
Processes using bacteriochlorophyll are actually a subset of processes of [anoxygenic photosynthesis](https://en.wikipedia.org/wiki/Anoxygenic_photosynthesis) (see also [here](https://web.archive.org/web/20190928002202/https://courses.cit.cornell.edu/biomi290/z.OldWebSite/ANOXY.HTML)). Anoyxgenic phoyosynthesis does not produce oxygen (hence "anoxygenic"). Water is not used as an electron donor (an alternative is H2S). [This](https://web.archive.org/web/20191030150524/https://msu.edu/course/mmg/301/Lec21.pdf) pdf has some very informative diagrams of the process (pages 6 and 7). Here's one (with someone else's notes on it!):
[](https://i.stack.imgur.com/pTk6H.png)
The big issue with using bacteriochlorophyll is that, to the best of scientists' knowledge, only some bacteria use it, not plants. You can probably circumvent this somehow by creating conditions in which normal photosynthesis (i.e. using chlorophyll) is not feasible. Perhaps H2O isn't too plentiful, while H2S is.
[Answer]
All life in the universe is probably carbon-based, so every planet capable of supporting life would need sufficient carbon in the atmosphere and/or soil to form organic molecules. I wrote a short work on this a few years ago: <https://www.dropbox.com/s/aai21mjdlyyw9fv/SiBiochem.pdf?dl=0>
To summarize:
>
> You need to base your biochemistry on an element with chemical properties similar to those of C (tetravalency, sp3 orbital hybridisation, etc). The only elements with the same properties as C are those in the C group, of which Si is the next lightest. The problem with this is that silanes (Si-O compounds) are all solid, inflexible and less stable than their equivalent organic molecules, which makes them difficult to use as building blocks (proteins, lipids, DNA, etc) and difficult to metabolise. Heavier elements in the C group suffer even more from this problem (and others)
>
>
>
As far as oxygen goes, I don't know whether another element could replace it; it's worth having a look on the internet or studying the properties of other elements in the oxygen group (or perhaps in the boron and nitrogen groups?).
If you stick to oxygen, there are plenty of molecules which could replace chlorophyll. Haemoglobin has esentially the same molecular structure (the differences are that its core is an iron atom instead of a magnesium atom and that some of the nitrogens are located in different places), so I believe haemoglobin could be usable for photosynthesis (and chlorophyll for oxygen transport in some sort of modified bloodstream) under certain conditions (I wanted to study this problem scientifically some time ago but never got around to it). You can also probably replace the magnesium with some other metallic atom and have something similar.
It's unlikely that you'll be able to get rid of nitrogen dependence if you stick to something chlorophyll-like, though.
The optical properties of chlorophyll-like molecules can be wildly different from those of chlorophyll itself (for example, haemoglobin scatters red light and absorbs green light, whereas chlorophyll scatters green light and absorbs blue and red light). Aside from any possible structural changes your non-chlorophyll-based plants might have, they would probably be primarily some colour other than green.
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A lot of more realistic depictions of dragons have their fire breath coming from some sort of flammable substance like a gas or liquid that their body produces and stores before they spew it that they then light to create the illusion or at least an approximation of 'breathing fire'... somehow.
My question is this. Could/Is-it-possible-for a creature evolve to grow steel teeth, or at least steel somewhere in their mouth, and have their tongue be tipped with some sort of flint-like stone or object that they could scrape against the steel in their mouth to create the spark that would light the flammable substance?
[Answer]
**The Flint**
Flint is a mineral; it is a sedimentary cryptocrystalline form of the mineral quartz.
Biomineralization is a naturally occurring trait of living organisms, and this is process is how seashells get formed, for example.
So, yes, your dragon is some biological manner have a “tongue of flint.” Maybe its tongue has surface that scales flint and regenerates dead tongue skin cells. Maybe your dragon’s mouth is a nice environment for the bacteria similar to the sea floor and it’s that bacteria which produces the mineralization process, which catalyzes on your dragon’s tongue.
**The Steel**
Biological production of steel is a bit tougher nut to crack. It doesn’t occur.
But it doesn’t need to occur. I get that you’re going after a literal “flint and steel” fire starting mechanism. But the purpose of the steel in a flint and steel kit is merely to serve as a (relatively softer) material for striking the harder flint against. It is but one, relatively later, materials used to manufacture a class of tools generally called a fire striker within the class of fire starting generally termed “percussion fire making.”
Percussion fire making involve the striking of one material against the other to cleave a small, hot, oxidizing metal particle that can ignite tinder. This contrasts other fire making methods such as volcanic ignition, meteorite strike, lightening, or friction (hand bow, etc.)
Early fire strikers, and fire making, predate the Iron Age and therefore steel. Early fire strikers were manufactured from a variety of iron pyrite. Also marcasite was used with flint and other stones to produce a high-temperature spark that could be used to create fire. For example, anthropologists believe that the "Iceman" called Ötzi may have used iron pyrite to make fire.
Marcasite, sometimes called “white iron pyrite”, is iron sulfide with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure.
It is a mineral, and that gets us back to mineralization. Or perhaps naturally produced teeth.
However, I would be apt to swap the two: the teeth should be the harder of the flint-and-steel mechanism, perhaps wearing somewhat over time. The tongue should be the sacrificial element, flaking off dead skin cells in the form of sparks that simply get regenerated over night.
Well, that’s how I see it anyway.
[Answer]
# Use Ferrocerium Instead
Ferrocerium is an alloy that is used to start fires, like a flint-and-steel. However, ferroceriums are far better. Namely, their sparks burn far hotter (making it easier to light the fire), and can be sparked on many types of edge
There is one problem: Cerium (a major part of ferrocerium) is not biologically active, at least not in animals. However, there is a solution: There are a few methanotrophic bacteria that do use cerium, and it's not completely implausible that bacteria like these could help pass these metals into the dragon's bloodstream. There is also the problem of getting the cerium, but if these dragons are the subterranean type, then they could easily get it from eating the right minerals
On the specific placement of the ferrocerium, it'd be best to have regular teeth, with the metal at the sides of the tongue, like the 'teeth' of a goose. This should allow the dragon to eat and move its mouth without causing sparks and wearing down its metal-parts. The teeth should also have a rough edge on the inner face, for quick and consisent sparking
The secretion of metallic parts seems quite plausible, as many species (including every basis for a dragon) already deposit minerals into their tissues. While metals are a little different, the principle should be the same
[Answer]
# fork(Prehensile)-tongued dragons:
It isn't impossible for a dragon to make a metal like iron [(but implausible and impractical)](https://worldbuilding.stackexchange.com/questions/214123/can-my-large-creatures-have-metal-scales?noredirect=1&lq=1), and it's not impossible for a dragon to have seeking behaviors to locate flint. But Why? Prior to the advent of steel, iron pyrite would and did work for a [fire striker](https://en.wikipedia.org/wiki/Fire_striker). Dragons could have seeking behaviors for iron and flint that would obtain the materials they need.
Dragons are portrayed as clever, even if they aren't fully intelligent. So let's say your dragon has a long, forked prehensile tongue. Before humans came along, dragons could have discovered flint and iron pyrite. Even if they can't think of flint and steel on their own, they can watch a human do it, and "steal steel" by simply taking flint and steel from a human.
With a tongue that can manipulate tools (and possibly direct the streams of flammable gasses), it's a simple enough task for a dragon to use it's tongue to strike flint and steel like humans do. The dragon can keep these items in it's cheek, or loll it's tongue out of it's mouth the keep them dry before use. If the iron needed to be associated with the teeth, you could simply wedge a piece of steel (or pyrite) between a couple of teeth to hold it in place.
[](https://i.stack.imgur.com/gvq5E.png)
[](https://i.stack.imgur.com/QbYKO.png)
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My creature is an alien roughly 3 meters tall while standing (roughly 2,5 meters at the shoulders, with arms that can touch the ground while standing upright) and weights roughly 220 kg (roughly 485 pounds). It's overall metabolism and organs involve a potent respiratory system like that of birds and pterosaurs an it's bones are also similarly structured, being pneumatic bones. My main concern is their wing design: at fist I planned for them to be bat-like, but I'm not the most knowledgeable in how active flapping flight works in its more complex details. I do understand that the mammalian respiratory system and bone structure are 2 important points in restraining the size of bats, but not whether their wing structure is a problem.
My question: can a large, 220 kg (485 pound) creature with a respiratory system and bone structure more similar to a bird's or pterosaur's make use of a bat wing structure efficiently to fly or would a wing closer in overall structure to a pterosaur's (like seen in the [azhdarchid](https://www.mindat.org/taxon-3238848.html) family) be the only alternative at its size?
*Clarification edit*: what I'm trying to know is whether the bat wing design (a wing membrane or patagium supported by at least 3 long digits) can still be effective in a larger flying creature such as the one I mentioned or if my only option is to rely on a wing more similar in structure to that of a pterosaur (in which the patagium is supported by a single elongated digit). I'm well aware that it's extremely unrealistic for such a large animal to beat its wings over 4 times a second like you'd see in some bat species.
As for type of flight and wing loading: ideally the creature should be able to take off vertically with its wings, so a low wing loading, preferably around 20-22 kg/m^2 would be ideal. For now since I'm more interested in whether it'd still be possible to employ the bat wing design, the creature needs to simply be able to fly in an open field devoid of obstacles, preferably without being too dependent on soaring flight based on air currents like you see in albatrosses, whose wings are I'll suited for powered flight.
Assume the planet is identical to earth with an atmosphere and similar to that of the late cretaceous period, because it essentially is (parallel dimensions, related to the plot, not to the question).
[Answer]
## You're fine
First bat wings are more [efficient wings](https://journals.biologists.com/jeb/article/218/5/653/14631/Bat-flight-aerodynamics-kinematics-and-flight) than birds, so switching to bat like wings just makes your creature more likely not less.
Second switching to a **bird cardiovascular system** increases its cardiovascular efficiency but may have little impact on the wings. Most of the bones in a birds wing are not pneumatic. making all the bones in a bat like wing pneumatic will have more impact than a birds wing, but how much is not clear. the limit on wings generally it not weight but loading, which is an effect of the total body weight of animal. It will make them better fliers because their *breathing* is more efficient and it can make wing bones stiffer, but the effect may not be large. whether they are powered fliers vs soarers really depends on how far you want them to travel, a powerful stroke means they will fly less often, soaring is just more efficent.
**Vertical take off**, again you are fine the largest animals to ever fly *Quetzalcoatlus* used vertical take off, pterosaurs cannot run, running take off is unique to birds due to their strange evolutionary history, having evolved from runners not climbers, and a giraffe sized animal is not climbing a tree.
220 kg is big but within the bounds of the [largest known animals to fly](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2981443/) (200–250 kg), which again we know used vertical take off.
[Answer]
**Probably not with the specific trio of ‘modern-day earth-like atmosphere’, ‘vertical takeoff’, and ‘bird/pterosaur respiratory/bone structure’.**
However, if you were willing to relax one or two of those, maybe.
There’s already [a lot of variety in bat wing morphology](http://a%20lot%20of%20variety%20in%20bat%20wing%20morphology), and some of the larger diurnal bat species already [use thermal or slope soaring](https://pubmed.ncbi.nlm.nih.gov/10637193/) during foraging flights to save energy, you'd need to apply strong evolutionary pressure to select for size and geography to promote soaring.
[This site](https://sites.google.com/site/anthonysgurps/dragon-physics) discusses some similar problems and potentially plausible solutions about the physics of ‘dragon flight’, based on a set [aspect ratio](https://en.wikipedia.org/wiki/Aspect_ratio_(aeronautics)) and [lift-to-drag](https://en.wikipedia.org/wiki/Lift-to-drag_ratio) ratio of the wings; the conclusion being highly improbable, biologically speaking, but not impossible (an enormous energy requirement powered by a small internal combustion engine and muscles inspired by dielectric elastomers).
Also, [this paper](https://www.researchgate.net/publication/26553081_Atmospheric_pressure_at_the_time_of_dinosaurs?fbclid=IwAR3vJI7axZOxZt0MJZZ-TE4y4elAIBKzLfvpaIV6BahkvhgfGOmyc8JKRPo) discusses the aeronautical differences of Quetzalcoatlus vs today’s birds, insects, and aircraft, and how an atmospheric pressure increase when Quetzalcoatlus existed may explain that. As this may have occurred at one point in Earth’s history, you could lean into the ‘parallel dimension’ aspect to handwave this.
Some ideas include:
* Higher atmospheric pressure than modern-day earth, if possible.
* **The right climate conditions for strong thermal currents and high winds.**
* Geography containing lots of verticality interspersed with plains.
* Convergent evolution from a gliding ancestor organism with patagia with evolutionary pressure for stronger, inflexible finger joints, and an abundance of airborne food.
* Novel power generation using a more alien respiratory/circulatory system.
[Answer]
## Square-qube law says... It's possible up to a certain point
There's a very good reason why larger creatures are the thing of legend and distant past, especially ones capable of flight. The larger the creature is the exponentially heavier it becomes and, after a certain point, any excess growth actually becomes a handicap rather than a benefit. If you want larger creatures in your world, you have to define where that line is and that becomes even harder if you want those creatures to fly.
Could you have a large creature weighing in slightly over 200kg that's capable of sustained flight? It could be done, but it's a stretch realistically speaking, since the creature would have to have pretty large wings and insanely powerful wing muscles in order to achieve sustained flight, which would force it to have at least half of its total body weight in its wings alone. The further you scale up the size of the creature, the more of its weight and power has to be diverted into the wings.
This is the main reason why western dragons are considered to be the most realistically depicted dragons. Their strength and their body-weight is concentrated in their wings and, the larger the dragon becomes, the smaller its actually body is and the more wingspan it requires.
[Answer]
If you want to retain your Earth like world (in other words not drop gravity or raise atmospheric pressure) then your creature can only get as big as Quetzalcoatlus Northropi. Look it up for details, but I think the graph gives a great idea of the scale.
[](https://i.stack.imgur.com/8Jkq6.png)
The answers of a previous question of mine might also be helpful:
[How CAN we scale up living creatures to be giant sized?](https://worldbuilding.stackexchange.com/questions/109716/how-can-we-scale-up-living-creatures-to-be-giant-sized)
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I have been bandying about some exotic mathematics ideas as the basis for a hard scifi setting, and I wonder what technology/alien life would "make sense," here, given the physics arising from the mathematics...
The core premise is that the universe has an [infinitary logic](https://plato.stanford.edu/entries/logic-infinitary/) assigned to it, where infinite sequences in the logic ground laws of physics (as something akin to, if not identical with, exceptionless regularities). Following [Smolin's lead](https://en.wikipedia.org/wiki/Time_Reborn), the idea is that at *t* = 0, κ & λ for the logic ℒ(κ,λ) are 0,0, with the initial expansion over the *t*-interval 0:1 being a consequence of ℒ(κ,λ) shifting to ℒ(ω,ω), such that a further shift in time (in the future) to ℒ(ω1,ω) results in accelerated expansion, so that the next shift has another cosmological effect that changes the laws of physics again, etc. The equation I assigned to these shifts technically has κ & λ go to ω4 & something else next, at the start of the story.
Things I need to avoid: (a) an immediate [Big Rip](https://en.wikipedia.org/wiki/Big_Rip); (b) **photon-induced overheating (the speed of light changes during shifts, becoming intrinsically faster, so more photons hit things in shorter periods of time)**. Things I need to have: (a) some means for aliens to use a shift to travel between parallel universes; (b) **interstellar travel made possible by the increased speed of light**.
I also want aliens who engage in mathematics primarily involving exotic [hyperoperations](https://en.wikipedia.org/wiki/Hyperoperation), e.g. via hyperoperators with negative indexes. For technical reasons, these would not be the inverses of the positive-index operators. My "assumption" is that these aliens (also "escapees" from another world destroyed by a Big Rip) would come from a universe where the very function that shifts the values of ℒ(κ,λ) there uses negative hyperoperations to compute κ & λ.
So another problem: how to describe the transformation of aliens from one sphere with different laws of physics, into beings compatible with the laws of physics of the world they've escaped into? I could have it that you can only shift into a world whose ℒ(κ,λ)-signature "lines up with" the signature of the world you're leaving.
I've considered trying to make most of the physics involved in these processes depend on [inflatons](https://en.wikipedia.org/wiki/Inflaton), such that either (a) these particles reemerge during shifts (embody them, even) or (b) some of these particles did not decay after the initial expansion but can be somehow "mined" from within black holes, and so the occurrent shift is part of what allows "black hole mining" (the specific idea I have is that [cosmic strings](https://en.wikipedia.org/wiki/Cosmic_string) exist and can be "plugged into" black holes to form the "mining" conduit; see e.g. [this article](https://www.newscientist.com/article/dn24713-to-kill-a-black-hole-recruit-a-cosmic-string-army/)).
More higher-level mathematics stuff: have Œ∫ be the number of time dimensions and Œª the number of space dimensions. Then spacetime being perceived as continuous is an elaborate consequence of the value of ùî† according with the Continuum Hypothesis. I was thinking that the ability to directly resolve the CH by intuition might even be one of the results of the shift for cognitive agents...
**Is the universe I am trying to describe, too unstable to survive?**
EDIT: here's the start of the shift equation:
{{{{0 ↑0 ℵ0} + ℵ1} × ℵ2}ℵ3} ↑↑ ℵ4}
So ℵ2ℵ3 = ℵ4, assuming the [GCH](https://www.britannica.com/science/generalized-continuum-hypothesis) here. Then the tetration goes to ℵω4, which is supposed to be the next shift. So technically κ goes to ω4 at the start of the story, which is "how" it is easier to "just see" the truth of 2ℵ0, here.
[Answer]
I think the problem here is a frame challenge one. You're in essence asking us to.design your universe, even though the question you ask is about stability.
The mathematics are a framework. Within that framework and the bounds of SciFi (even hard grounded SciFi), there is so much flexibility, that the only answer I can think of to "Is it stable" is "depends on your design". If you then ask what design to pick, you're asking us to choose your universe.
Its so open, that in effect you are asking which fundamental structures to choose. maybe update the question to focus on the problems you are trying to work round by doing so? Right now it reads more like "I just arbitrarily want my universe to be a mathematical universe with infinities, which one shall I choose so it can be that?" *(and I appreciate that's probably not how it is, but its how the question comes over)*
[Answer]
/ I was thinking that the ability to directly resolve the CH by intuition might even be one of the results of the shift for cognitive agents.../
I answer your problem of space, time and physical law with Milton and the stuff of stories.
<https://www.poetryfoundation.org/poems/45718/paradise-lost-book-1-1674-version>
>
> Is this the Region, this the Soil, the Clime,
>
>
> Said then the lost Arch-Angel, this the seat
>
>
> That we must change for Heav'n, this mournful gloom
>
>
> For that celestial light? Be it so, since he
>
>
> Who now is Sovran can dispose and bid
>
>
> What shall be right: farthest from him his best
>
>
> Whom reason hath equald, force hath made supream
>
>
> Above his equals. Farewel happy Fields
>
>
> Where Joy for ever dwells: Hail horrours, hail
>
>
> Infernal world, and thou profoundest Hell
>
>
> Receive thy new Possessor: One who brings
>
>
> A mind not to be chang'd by Place or Time.
>
>
>
Your agents have moved either by design, or compulsion or both, and find themselves different in different place. But their minds are "not to be chang'd by Place or Time" and Satan here demonstrates his /ability to directly resolve the CH by intuition/. Perhaps cognition operates by its own rules? A matter for their scientists who can wrap heads around matters of κ and λ. There is a place for those scientists and their musings and speculation. You will need a Satan character, who recognizes what has happened, and recognizes himself as himself, and moves on with his agenda.
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I want to make an assassins competition which would involve players being presented with a number of poisons and having to identify them. I have thought of using Hellebore, Hemlock, Foxglove, Nightshade(Belladonna), and Monkshood (Wolfsbaine).
The test would comprise of the five plants being present to them and five goblet to which the equivalent poison has been added to a drink, and they would be asked to match them correctly.
My problem is that I can't find any info on what the poison for these plants once prepared would look/smell like, and other info that players could use to identify the poisons. Anyone know where I would find this kind of info? How would medieval people detect/identify poisons?
Any help on gamefying my poison competition welcome :)
[Answer]
**Culpepper can help!**
[Culpepper's Complete Herbal](https://www.gutenberg.org/files/49513/49513-h/49513-h.htm)
>
> Hemlock: …The whole plant, and every part, **has a strong, heady, and
> ill favored scent**. Hemlock is exceedingly cold, and very dangerous,
> especially to be taken inwardly.
>
>
> Hellebore (Black): …It is an herb of Saturn, and therefore no marvel
> if it has some sullen conditions with it, and would be far safer,
> being purified by the alchemist than given raw… ;also being beaten to
> powder and strewed upon foul ulcers, it eats away the dead flesh, and
> instantly heals them: nay, it helps gangrenes in the beginning.
>
>
> Hellebore (White). The roots are thick at the head, white on the
> inside and very full of fibers all round, of a **hot nauseous taste.**
> Like the former it is it cold Saturnine plant, and possesses but to an
> inferior degree the virtues of black hellebore.
>
>
> Foxglove: the flowers have no scent, but **the leaves have a bitter hot
> taste…** the urban is familiarly and frequently used by the Italians to
> heal any fresh or green wound, the leaves being but bruised and bound
> thereon… I am confident that an ointment thereof is one of the best
> remedies for a scabby head.
>
>
> Nightshade (common): the whole plant is of **a watery and insipid taste**,
> but the juice of the berries is somewhat viscous, and of a cooling
> and binding quantity. Be sure you do not mistake the Deadly
> Nightshade for this.
>
>
> Nightshade (deadly): … berries of the size of cherries, black and
> shining **when ripe, of a sweetish and mawkish tast**e. Only a part of
> this plant has its uses. This Nightshade bears a very bad character as
> being of a poisonous nature. It is not good at all for inward uses…
>
>
> Aconite – we have many poisonous aconites growing in the fields, of
> which we ought to be cautious: but there is a medicinal one kept in
> the shop; this is called the wholesome aconite; anthora, and wholesome
> wolfsbane… a decoction of the root is good lotion to wash the parts
> bitten by venomous creatures but it is not much regarded at this time,
> and should be cautiously kept out of children’s way, for there is a
> farina in the flower, which is very dangerous is blown in the eyes;
> the leaves also, if rubbed on the skin, irritate and cause soreness.
>
>
>
Culpepper's herbal was written in the mid 1600s. He goes on at some length about each plant in his very lengthy (I would estimate 1000+ entries) reference work and for the majority he includes a sentence on flavor and odor. I have pasted these here. They are not thorough but I feel confident they are correct.
His work includes only herbs he considers to have medical application - oleander, for example, was certainly known to him but does not appear. Some seem unjust; dill for example is said (in comparison to fennel) to have a "stronger and unpleasant scent". !!
It is worth noting that an assassin might not only use potions, but also blown powders, poison daggers etc. Also a contest would include other herbs as well to keep people guessing.
] |
[Question]
[
So, back to werewolves for a bit. Given that they're as intelligent as humans and have several enemies, they'd most likely try to become more adept in combat, one part of that is martial arts.
Now, moves that don't aim to kill will most likely not, but the ones that do will definitely want to include jaws into their repertoire.
Werewolves are digitigrade and upright humanoid creatures that usually stand at around 190 cm. Other than the legs, most of their difference in anatomy are their thicker necks and head that resembles that of the *canis lupus lupus* but obviously scaled to fit the proportions.
Werewolves possess strong core muscles. Their muscle fibers are uniformly made up of type 2a and type 1 across the body, giving them better endurance and more options for moves, but making them weaker per unit mass than vampires, who only have type 2a in their legs and only type 2b in the arms and core muscles.
The vampire bit is just extra info, it won't come up in this question.
**So, now with that info dumped on your head, how exactly would werewolves use their jaws in combat? My main interests are grappling, killing blows and what limitation/weakness would the jaws have. These aren't separate questions, more like bullet points in an outline that affect one another quite a bit.**
The opponents are going to be humans who might or might not have plate armor.
[Answer]
**Killing blows**
The thing about jaws is that they are a very high-risk, high-reward weapon for a biped with longer forearms than neck. Jaws can inflict more damage in a single blow than fists or claws can (source: just about everything in nature), *but* they require getting your eyes and throat very close to your enemy. This means they can easily retaliate with more damage to your vital areas than you are dealing to them, even if they are just struggling in a panic. Having talked with people who work with mentally handicapped children, where biting is sometimes an issue, it's actually really easy to get out of a bite hold if that's all someone's doing and you keep cool. Just push backwards against the bite while pushing back on their face, which forces the jaws open enough for you to get free.
Given this, the best thing to do is to save biting for a final blow, *after* you've made it impossible for your opponent to retaliate and possibly after they're tired out and can't struggle very effectively, in order to finish them off.
Real wolves don't rely on their bites doing damage that much. They use shallow, slashing bites to wound the prey as they are chasing it as a pack, driving it to exhaustion before piling on and tearing it apart like stereotypical depictions of piranhas. Exhaustion of the prey is a bigger factor than any physical damage. If a bison or moose doesn't fall for the wolves' tricks and run, the wolves can't really do much to it. This is one reason why "lone wolves" don't work like they do in media, lone wolves are screwed because they can't hunt large prey by themselves and are forced to subsist on carrion or small game (rabbits, marmots, young deer etc.). The "threat factor" from wolves comes from their numbers, and individually they are much less impressive in combat than cats, bears, and even hyenas.
] |
[Question]
[
So, I've heard that above around 35% O2 concentration in Earth-like atmospheres leads to wildfires that just never go out.
I'm thinking of using this like California, with its regularly occuring fires that help clear the land for new growth, but on a global scale.
Every couple of years, the O2 conc. is high enough for fires to never go out, so they spread and burn the world down but also use up a lot of that oxygen to the point that they may die again. Plants then regrow raising the O2 back up to the threshold starting the cycle anew.
If I set the oxygen concentration to or just below that threshold, will this be sustainable?
If not, how could I get this to work?
[Answer]
**Boom bust cycles.**
1. Oceanic and land based plants compete for CO2 and are limited by CO2 availability.
2. Oceanic has an edge in that they cannot burn.
3. When O2 gets high enough the land burns.
4. Free from competition with land plants, and with all that land carbon now available as CO2, the ocean plants have a burst of growth.
5. Ocean plants overgrow the availability of their noncarbon nutrients (iron, nitrogen, phosphorus) and their populations crash.
6. Oxygen levels fall because land and water are now depleted of photosynthesizers.
7. Land and water life begins to regrow. Land has an edge because there are more nutrients available in the soil than in open ocean. Land regrows first. Ocean starts later.
8. Oceanic and land based plants compete for CO2 and are limited by CO2 availability.
[Answer]
What would restrain fires from burning in the "low" periods? Any lightning could start one, and compost heaps that get too dry have been known to burst into flame, however rarely -- naturally accumulating dry organic matter might to do the same.
Such fires would use up the fuel and oxygen for the world-wide bursts, and create natural fire-breaks that would limit spread. Other natural firebreaks such as bodies of water, prevailing winds, desert, rainstorms, and bare rock would also prevent the necessary sparks from flying all over the world. Any condition, such as high winds, that would spread the fire far and wide during the high-oxygen period would also spread fire in the low-oxygen periods, if not so widely.
The variation in fire between the high and low oxygen periods would be continuous, not a step function. You would need some reason other than "low oxygen" to explain why fires were not a regional factor as the oxygen built up, and a major regional factor as it approached the high period.
[Answer]
fire needs three things fuel, oxygen and temperature ... so there would also be a temperature / humidity component to the excellent cycle willk describes.
unless you want to use the planet's orbital eccentricity to regulate temperatures ....
coinciding with stage 3 would be a drop in temperature and humidity but first the ash fertilisation kickstarts stage 4
stage 5 would see a second longer drop in temperature especially along the high latitude coast as albedo changes, further encouraging step 6
stage 7 would be spotty because glacial melt would be encouraged by land growth changing the albedo but the new river deltas would be the kickstart for ocean growth
] |
[Question]
[
I'm presently in the process of developing my plans for a flintlock fantasy series. It's high magic, but one form of magic in the setting, Arcane Magic, is heavily based in science. The energy that powers it, Aethyr, can bend the laws of physics but not outright break them. (You can't turn someone into a frog with Arcane Magic, in other words.) My protagonist, Perdita, is an Arcane Engineer. She's someone who makes magical devices of an Arcane nature. Among her creations is a belt that can perform a Spell called the *Sphere of Meteoric Conversion.* Here's the basic idea of how it works:
When Perdita falls beyond a certain distance, the belt activates, using Aethyr to create a magical bubble around her. When she hits the ground (or any solid object larger than the average bird,) the *Sphere of Meteoric Conversion* converts all her kinetic energy *and* the kinetic energy of the surface pushing back against her (that is, the equal and opposite reaction) into another kind of energy or simply redirect the kinetic energy away from her.
By this I mean *that the bubble* absorbs all the energy of the impact and transfers it away from Perdita so she takes no damage, either by directing it at something other than her or by converting it into a different kind of energy which is then directed away from her.
So, the bubble may just cause all the absorbed kinetic energy to go outward from it in all directions, like a bomb going off. Or it may convert all the kinetic energy into thermal or radiant energy and release it outward in all directions. I suppose converting it into sound is also something it can do.
The *Sphere of Meteoric Conversion* can also direct the absorbed and converted kinetic energy in a ring or a beam. For example, when she hits, the bubble discharges a disk of light, heat, or sound along its proverbial equator. Or it may discharge a heat beam or laser beam directly up into the air. The point is that it takes the energy of the impact and turns it into something else to be used in a different way while Perdita remains safe inside the bubble.
And, before you ask, yes, the amount of Aethyr needed to create the *Sphere of Meteoric Conversion* is considerable, especially if she's moving at terminal velocity. The belt is going to need some time to "cool down" (not literally) before it can generate the Spell again.
Also, the Spell doesn't have to convert all the kinetic energy into just one other type of energy. It can convert some of it into radiant energy, some of it into thermal energy, some of it into sound, and just redirect any left over kinetic energy away from Perdita.
What I need help with is determining the math for the *Sphere of Meteoric Conversion.* I want to make sure the math holds up in the books. Also, is there anything I'm overlooking or missing with this idea? I know it's magic, but, like I said, Arcane Magic is intended to be as science based as possible.
It's going to be interesting seeing the feedback I get on this. I hope that it presents some of you with a fun puzzle, at the very least.
**Edit and Update**
Okay, it seems I need to clarify another point here: The purpose of the *Sphere of Meteoric Conversion* is to weaponize the kinetic energy of the impact *in addition* to preventing Perdita from taking any damage. Alternatively, it will convert the kinetic energy into something harmless so she doesn't hurt herself, her allies on the ground, or do any significant property damage. I think it will be easier to explain this with a few examples. Some things that will be applicable in all the examples are the following:
Perdita is a *Half-Orc*, not a Human. She's 6'7" tall and weighs about 220 lbs. The gear she usually has on her probably comes to a total of 30 lbs., minimum. (That's her leather garments, melee weapons, flintlock guns, ammunition, etc.) So, total weight is around 250 lbs.
**Example 1:** Perdita is up on the tower of a castle. In the courtyard below is a horde of Ghouls (basically zombies) trying to break into the front entrance of the main keep. Perdita has the Mage with her use a Spell to launch her high into the air so she then comes down in the center of the mob of Ghouls. The *Sphere of Meteoric Conversion* changes the kinetic energy of the impact into thermal radiation and releases it as a disk from the "equator" of the bubble. Ghouls are weak against extreme heat. Or she may have the thermal radiation released as a beam that targets one really big Ghoul that's the size of the Incredible Hulk. The point is that she uses the kinetic energy of her impact to burn some Undead.
**Example 2:** Perdita is on a floating island over the ocean. She gets blown off it, either by a powerful burst of wind or a Mage using a Spell. As she falls towards the water below, she see a Sea Monster rising up, its jaws open to catch her. She activates the *Sphere of Meteoric Conversion* and adjust it to its "Zappy" setting. When she lands in the Sea Monster's mouth, the kinetic energy is converted into a pulse of electricity.
**Example 3:** Perdita is on an airship and, for one reason or another, gets thrown off of it. As she falls to the ground, she sees that she is headed toward a park where an aristocratic girl is having her Quinceañera. And the birthday girl has just received a puppy as her gift from her parents. Not wanting to become a party crashing in the most literal sense of the term, Perdita activates the *Sphere of Meteoric Conversion* and adjusts it to its "Harmless" setting. On impact, all the kinetic energy is converted into a beam of light (perhaps visible light, perhaps radio waves or something that won't hurt anyone.) The only damage done to the festivities is in the form of extreme awkwardness.
These examples are hopefully sufficient to explain the the *why* of the *Sphere of Meteoric Conversion.* Perdita isn't just trying to protect herself from injury and death. She also wants *to harness* the kinetic energy of the impact in some way or just direct away so nobody is hurt and no property damage is caused. If she just wants to slow her fall so she lands safely, she'll use a different kind of Spell, but there are situations where a slow descent would be a problem, like if that would make her an easy target to shoot from the ground or if that would give someone she's chasing time to escape and hide.
Hopefully this clarifies what I'm trying to figure out with this post. Also, having some examples of how to use the equations provided would be helpful, since I'm not a physicist and don't know what all the symbols in some of the equations mean without being told first. Once I do know, then I can use the equations myself, however, so I'm not asking other people to do all the calculations for me. I hope this clears things up.
[Answer]
```
When Perdita falls beyond a certain distance, the belt activates,
using Aethyr to create a magical bubble around her. When she hits
the ground (or any solid object larger than the average bird,) the
Sphere of Meteoric Conversion converts all her kinetic energy and
the kinetic energy of the surface pushing back against her (that
is, the equal and opposite reaction) into another kind of energy
or simply redirect the kinetic energy away from her.
```
There are two problems with this:
1. The ground doesn't have kinetic energy separate from or opposite to Perdita. And exactly how much kinetic energy there is depends on what frame you are doing the calculation in. The relevant frame for energy dissipation in a collision is the center-of-mass, zero-momentum frame of the colliding objects; when one of those object is *the ground*, the center-of-mass frame is for all practical purposes indistinguishable from the ground frame, and all of the kinetic energy is Perdita's.
2. The ground *does* exert an equal-and-opposite *force* on Perdita, thus transferring momentum to her and accelerating her to match velocities with the ground. It is that process which is responsible for injury and death from falls. Energy isn't irrelevant, but it's not the major player here; dissipating energy is easy. Limiting *acceleration* is key to safety. Perdita could absorb all of the kinetic energy of a terminal-velocity freefall into her own body as heat and be no worse for it, but that's no good if differential acceleration turns the physical structure of her body into jello.
So, the bubble needs to do some combination of three things:
1. Slow her descent, spreading the acceleration over a longer distance to keep the g forces survivable. This is what, e.g., crumple zones in cars do--they crush so that the body of the car, containing squishy passengers, can continue moving for a few more feet after a crash, over which distance it can slow more gradually. This is also what airbags are for--they ensure that the passenger's body begins accelerating *before* hitting the steering wheel / dashboard / windshield, rather than doing at all at once on impact with something hard and unforgiving.
2. Magically stiffen the materials of her body so that all parts of her experience near-identical accelerations, and thus are not torn apart by differentials in momentum transfer. This kind of what g-suits do--by applying compressive forces to certain parts of the body, they ensure the g-load is distributed more evenly over the whole body, thus helping to prevent blackouts. This is where intentional energy dissipation becomes relevant; if the bubble and everything in it is super-stiff, it will just *bounce*. Perhaps the bubble could have multiple layers; an inner layer that briefly freezes Perdita's body, and an outer layer that slows the inner layer down over some finite distance and dumps the kinetic energy into heat. Like dropping a frozen egg inside a balloon full of jello.
3. Automatically re-orient Perdita's body into the most g-tolerant position. People can survive much higher accelerations on their backs than from any other direction, which is why infant car seats are rear-facing; not only does it help spread the load of a crash over a wider surface area compared to straining against relatively thin straps, but even controlling for equal support, the human body is simply more resistance to injury in that orientation.
The relevant math is as follows:
$KE = \frac{1}{2}mv^2$
Suppose Perdita weighs around 75kg (a reasonable number for a healthy adult human woman). Terminal velocity for people is somewhere around 55m/s. That means she has to dissipate $\frac{1}{2}(75kg)(55m/s)^2 = 113,437.5 J$ of energy, or around 27.1 food Calories. I.e., enough energy to raise 27kg of water by 1 degree celsius. Or all of Perdita's body by considerably less.
Meanwhile, people can easily be seriously injured (or, if old or just really unlucky, outright killed) by low-velocity falls just from tripping on the sidewalk--it's not how much energy is involved, it is *how* that energy is applied in conjunction with momentum.
$p = mv$
Perdita's momentum is $4125 \frac{m\ kg}{s}$
$a = \frac{v^2}{2d}$
Above an acceleration of 3g, Perdita will be uncomfortable. Above about 50g, she will sustain injury regardless of orientation. Above around 10g, you need to start employing those other measures like automatic reorientation and magically redistributing forces to avoid serious injury or death from falling the Wrong Way. So, if we want to simply dissipate energy into heat by slowing Perdita's descent, the bubble needs to have area of effect large enough to start slowing her descent at least $d = \frac{v^2}{2a} = \frac{(55m/s)^2}{6g} \approx 51.5m$ So, well above rooftop height if she's already at terminal velocity. At 10g with automatic reorientation, you're looking at a 15-meter bubble.
If the bubble itself supplies additional air resistance, that terminal velocity will come down a bit, which helps. But if you want Perdita to land comfortably, on her feet so she can walk away (and maybe to an awesome superhero power-pose), and without the bubble interfering with the landscape in a 100-foot wide circle all around, I think you're pretty much gonna have to look at the "magically freeze her solid" / "Star Trek inertial dampeners" option.
EDIT, to account for the question edit:
```
Perdita is a Half-Orc, not a Human. She's 6'7" tall [...].
So, total weight is around 250 lbs.
```
250lbs is about 113kg. So, applying the kinetic energy equation again, and assuming she's still falling at a typical terminal velocity for a skydiver, she's got a total kinetic energy of $\frac{1}{2}(113kg)(55m/s)^2 = 170,912.5J$ To convert joules to kilocalories (of "food calories", where 1 kilocalorie is enough energy to heat a kilogram of water by 1 degree--a decent approximation for how much you will heat a squishy meatbag), just divide by 4184. Ergo, Perdita has access to about 41 (rounding up) kilocalories, enough kinetic energy from her fall to heat 41 kilos of ghoul by 1 degree. That's not much. She will not be incinerating any undead with that.
However, once again we have to note that what matters is not really how much energy is available, but precisely how it is applied. Bullets have far less energy than that, but they're still lethal. If all that energy is released as an instantaneous flash of isotropic radiation, you won't incinerate or even set fire to any ghouls, but you might give them some nasty sunburns as most of the radiation is absorbed in the first few millimeters of skin / rotting flesh. That may or may not slow them down, depending on precisely how your flavor of undead happen to work.
And if you concentrate that energy into a coherent beam, well... you can heat 1 gram of water by 40,000 degrees (not really, 'cause there's a phase change to worry about after a mere 100 degrees max, but that hardly matters at this scale). In other words, you can flash-vaporize a tiny chunk of ghoul flesh, causing it to violently explode as if it had been hit by a bullet. Or several small chunks, from several different ghouls, if Perdita has enough control to direct multiple beams like that.
Enough energy to make the ghouls uncomfortable from extreme heat? No way. Enough energy to seriously mess up their day through other means? Absolutely.
```
She activates the Sphere of Meteoric Conversion and adjust it to its
"Zappy" setting. When she lands in the Sea Monster's mouth, the kinetic
energy is converted into a pulse of electricity.
```
What matters here is amperage, and current path. Trivially, we have the same total amount of energy at our disposal, and it could just be turned into heat by unconstrained electrical discharge through the creature; depending on the precise incidental current path, maybe that ends up mildly warming the creature (no help at all), or maybe it ends up seriously burning a small chunk, causing it great pain, and maybe actual disability or maybe not depending on exactly which small chunk gets burned.
However, again, *how the energy is applied matters*. If she can direct an electrical discharge to just the right part of the animal (say, through its brain, or heart), very tiny currents can cause death--you only need about 100 to 200 milliamps for less than a second to irreversibly screw up the creature's nervous system, if it's applied in just the right place.
The relevant formula in this case is $W = RI^2$, where W is power, R is resistance, and I is current. If we know how long we need the shock to last, we can replace power with total energy (which we know, from Perdita's kinetic energy), to get $E = TRI^2$. The electrical resistance of wet flesh is around 300Ω, and we want a current of around 150mA, so if we generously assume that we need the shock to last for at least 1 second to definitely incapacitate the creature, we get $E = (1s)(300Ω)(0.15A)^2 = 6.75J$. *Way* less than Perdita's total kinetic energy budget. So, yeah, she can electrocute the sea monster easily.
```
As she falls to the ground, she sees that she is headed toward a park [...]
Not wanting to become a party crashing in the most literal sense of
the term, Perdita activates the Sphere of Meteoric Conversion and
adjusts it to its "Harmless" setting. On impact, all the kinetic energy
is converted into a beam of light[....] The only damage done to the
festivities is in the form of extreme awkwardness.
```
Not even necessary. All of the kinetic energy can simply be dissipated as heat--into Perdita's body, the air, the ground, some thermal radiation--and if it's not specifically focused somewhere, it would hardly be noticed.
[Answer]
Well, I'm not sure if what you describe is bending the laws of physics less than transforming someone into a frog. It's a very very fancy energy converter :)
In that case, being close to physics would probably mean to assure the [conservation of energy](https://en.wikipedia.org/wiki/First_law_of_thermodynamics). Some examples:
* Kinetic energy: $W=\frac12mv^2$
* Electrical energy: $W=Q\cdot U=U\cdot I\cdot t$
* [Heating](https://en.wikipedia.org/wiki/Heat_capacity) (with heat capacity $C$): $W=C \cdot \Delta T$
* [Black-body radiation](https://en.wikipedia.org/wiki/Black-body_radiation#Stefan%E2%80%93Boltzmann_law) : $W=P \cdot t= \sigma A T^4 \cdot t$
* LASER radiation: Found some examples for different [power](https://en.wikipedia.org/wiki/Laser#Examples_by_power). Like black body radiation the power would depend on the duration of the pulse.
* [Sound](https://en.wikipedia.org/wiki/Sound_energy): $W = W\_\mathrm{potential} + W\_\mathrm{kinetic} = \int\_V \frac{p^2}{2 \rho\_0 c^2}\, \mathrm{d}V + \int\_V \frac{\rho v^2}{2}\, \mathrm{d}V$, and with the sound pressure $p$ you get the [sound pressure level](https://en.wikipedia.org/wiki/Sound_pressure#Sound_pressure_level) in decibel.
Actually you would also need to consider entropy. It's always increasing of course, but does the conversion of energy require *the same* entropy increase than your original (kinetic) event? But then your magic probably wouldn't be possible at all. So you should accept to mess with entropy, but conserve the energy.
] |
[Question]
[
Just an idea that had me doing a lot of navel gazing. Both planets are habitable to carbon based life forms, but intelligent life on each planet evolves very differently.
Eventually, the two life forms become aware of each other. It would be more of a sociological space opera than hard science. Perhaps each race will have the wisdom to leave the other alone and observe from afar. Providing that gravitational and orbital rules would allow this.
[Answer]
Yes, and there already exists one in our solar system.
Pluto and Charon are of two very similar sizes and orbit each other somewhat stably. Although the both of them are considered dwarf planets/moons, they should be big enough to support some kind of life, even if it is dissimilar to that on earth. If they were located closer to the sun and had a source of liquid water, then it is possible for life to form on either -- or both -- planets.
[Answer]
It is very much possible for two planets to orbit each other in the same habitable zone. These binary planet systems can occur in nature and we even have one here in our solar system with Pluto and its moon Charon. Granted Charon is only half the size of Pluto and considered a moon it is massive enough to effect Pluto's center of gravity. So yes two planets can orbit each other in the same habitable zone of a star. Actually some scientists say that a stars habitable can hold as much as 5 planets if the conditions are right and some say as much as 7 but the conditions for 7 planets in the same habitable zone are very rare. So in short, yes two planets can orbit each other in a stars habitable zone.
] |
[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.
For the purpose of this post, full spectrum means a non-trivial number of frequencies within a non-trivial band. So human eyes aren't full spectrum within the visual range (each cone is wide band, they overlap and there are only three) but ten or twenty relatively narrow non-overlapping channels covering the full width would. I'm defining it up-front so that it's clear what I'm discussing.
I know that you can link radio telescopes over thousands of miles with a collecting area of a square kilometre. It's called SKA and it's currently being built.
Likewise, I know that you can build optical interferometers, but currently, none are capable of resolving a visual image.
Max Tegmark built a huge interferometer (either microwave or infrared, I'm unsure), the Omniscope, for looking at the cosmic background radiation.
But here you run into the first problem. The average distance to the asteroid belt from the sun is 3.2 AU, so we can treat our disk of radio telescopes as having a diameter of 6.4 AU and a circumference of 32.2 AU. Even if you processed the data on Earth, half that disk isn't visible, so you've got to transmit the data over unreliable, non-deterministic, low-bandwidth, high-latency links for 34.2 AU (distance to a common transmitter since there's only one deep space network plus distance to Earth). The non-determinism is the potential killer as you have no means of determining how to overlay the data.
The second problem is that even optical interferometry is limited. For full-spectrum, you've got to get it through UV and into X-Ray, and telescopes have to look over much narrower bands. I don't know if such telescopes are possible.
Given that a greater range of telescopes complicates data delivery (you've got more complicated paths to get the data from A to B because telescopes want to transmit their own data, bandwidth is constrained because you're using radio telescopes and interferometry still has to patch the data together), it's reasonable to theorize that you have a minimum number of relay stations elsewhere in the belt for the number of telescopes.
But you've now added the number of places that can collide with other objects, that can fail due to hard radiation in space, and that move unpredictably (N-body problem) relative to the telescopes they're relaying.
So we can say that there should be an upper limit, a bound beyond which either the telescopes can't be linked as an interferometer due to communications problems, where there's just no added value (an interferometer of half the size and twice the time base will see more), or where the probability of failure from any cause exceeds the value of the data obtained in the mean time between failures. The exact cause of the limit is irrelevant, although if there is published science on this, it would be good to see.
We can also say that there is an upper frequency beyond which interferometry is impossible with any known science. The reason doesn't matter, just the bound, although, again, the science would be good to see if published.
Because the asteroids move relative to each other, the change in the relative position of each obviously impacts the timebase (unless you create yet another mechanism for tracking position, with the unreliability that creates). The tools used in synthetic aperture receivers might be useful since you can in principle treat the motion as simply receiving on different spots on your fixed virtual dish.
If there is a function tying maximum size to maximum frequency, that would be wonderful, as then you can plot the full range of possibilities.
Otherwise, how large of a telescope over how large of a range of frequencies over how many bands could you have? Would you need to create an original ringworld (disconnected platforms in a ring) to build this, or can you utilize the asteroid belt with minimal impact?
(To clarify, this last bit is the question of interest.)
[Answer]
>
> For the purpose of this post, full spectrum means a non-trivial number of frequencies within a non-trivial band. So human eyes aren't full spectrum within the visual range (each cone is wide band, they overlap and there are only three) but ten or twenty relatively narrow non-overlapping channels covering the full width would. I'm defining it up-front so that it's clear what I'm discussing.
>
>
>
Not a big deal. Multi spectral charge-coupled device (CCD) cameras are out there.
>
> Likewise, I know that you can build optical interferometers, but currently, none are capable of resolving a visual image.
>
>
>
I am not an expert on the subject, but as far as I can tell [here](https://en.wikipedia.org/wiki/Astronomical_optical_interferometry), optical interferometers that resolve visual images either exist or are in prototyping.
>
> But here you run into the first problem. The average distance to the asteroid belt from the sun is 3.2 AU, so we can treat our disk of radio telescopes as having a diameter of 6.4 AU and a circumference of 32.2 AU. Even if you processed the data on Earth, half that disk isn't visible, so you've got to transmit the data over unreliable, non-deterministic, low-bandwidth, high-latency links for 34.2 AU (distance to a common transmitter since there's only one deep space network plus distance to Earth). The non-determinism is the potential killer as you have no means of determining how to overlay the data.
>
>
>
From what I've read, the solution used in other large setups is to take time stamped snapshots of the data. The trick would be keeping the clocks in sync, which is not an unreasonable problem. The imagery wouldn't be live. Would that be a problem?
>
> Given that a greater range of telescopes complicates data delivery (you've got more complicated paths to get the data from A to B because telescopes want to transmit their own data, bandwidth is constrained because you're using radio telescopes and interferometry still has to patch the data together), it's reasonable to theorize that you have a minimum number of relay stations elsewhere in the belt for the number of telescopes.
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You could use a mesh network. The most radial nodes passing their information inward. It would require less power and be more fault tolerant.
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> But you've now added the number of places that can collide with other objects, that can fail due to hard radiation in space, and that move unpredictably (N-body problem) relative to the telescopes they're relaying.
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The nodes could determine their own positions by Kalman filtering inputs of :
* on-board accelerometer reading, plus last known velocity and position
* latency to nearest mesh network node (or multiple nodes) (this technique is used by your cell phone to determine location as a supplement to GPS)
* range and bearing (determined by luminance) to the sun
* latency of timestamped pulses from Earth or other emitters on your system (GPS), which can also be used to measure clock drift
>
> So we can say that there should be an upper limit, a bound beyond which either the telescopes can't be linked as an interferometer due to communications problems, where there's just no added value (an interferometer of half the size and twice the time base will see more), or where the probability of failure from any cause exceeds the value of the data obtained in the mean time between failures. The exact cause of the limit is irrelevant, although if there is published science on this, it would be good to see.
>
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> We can also say that there is an upper frequency beyond which interferometry is impossible with any known science. The reason doesn't matter, just the bound, although, again, the science would be good to see if published.
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I'm not certain that either of these is true.
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> If there is a function tying maximum size to maximum frequency, that would be wonderful, as then you can plot the full range of possibilities.
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I haven't seen one, but I'll take a stab.
* Assuming your communication channel (with some factor of safety) can reliably communicate 'n' bits per second.
* Assuming your CCD has a fixed number of 'p' cells/pixels which will be exposed to 'f' filters at different frequencies, and that the total size in bits of any frame is 'P' = f p
* Assuming that each observer node can take 'i' time-stamped observations per second (in synch with the other nodes), the total transmission size (in bits per second) of each observer node 'I' = P i = f p i
* Given 'N' is the maximum number of nodes
* Assuming processing time is not a consideration, and that the communication pipeline is the primary limitation
For the thing to work, it must be true that n >= I N. You can set n = I N, and solve for the variables you like.
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> Otherwise, how large of a telescope over how large of a range of frequencies over how many bands could you have? Would you need to create an original ringworld (disconnected platforms in a ring) to build this, or can you utilize the asteroid belt with minimal impact?
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The asteroid belt seems like an unsafe place (to me) to place observation stations. I would think you could just place your nodes in orbits in what we tend to think of as empty space. Your choice, of course.
[Answer]
Now, forgive me if I am missing some things, but what you are looking for in this post does not seem to be that challenging. I'll propose a solution with near-future technology.
# Summary
* Use two large-ish asteroids in the belt in locations that make them unlikely to be hit by space debris.
* You can't use a space station due to vibration problems, you need to build into an asteroid with some serious mass.
* Do not use the interferometer for objects in the plane of the solar system, instead use it for objects closer to the axis of rotation of the solar system.
* Use multiple telescopes/apertures to get the spectrum you desire
* Coordinate image taking with a constellation of navigation satellites
* Aggregate and post-process information later
# Sources
* On the asteroid belt's orbital and size distribution. [Gladman, B., et al., 2009.](http://orbit.psi.edu/%7Etricaric/pdf/skads.pdf)
* The application of interferometry to optical astronomy imaging. [Baldwin, J. and Haniff, C., 2002](http://scholar.google.com/scholar_url?url=http://www.mrao.cam.ac.uk/projects/OAS/publications/fulltext/tyoung.ps&hl=en&sa=X&scisig=AAGBfm36WAy9F4ovtnRzdKSeuG2aHWJrig&nossl=1&oi=scholarr)
* Integrated optics for astronomical intereferometry, Part I. [Malbert, F. et al., 1999](https://aas.aanda.org/articles/aas/pdf/1999/13/ds1695.pdf?access=ok)
* Integrated optics for astronomical intereferometry, Part II. [Berger, J. et al., 1999](https://aas.aanda.org/articles/aas/pdf/1999/16/ds1697.pdf)
* Integrated optics for astronomical intereferometry, Part IV. [Berger, J. et al., 2001](https://www.aanda.org/articles/aa/full/2001/36/aade161/aade161.right.html)
* Integrated optics for astronomical intereferometry, Part VI. [LeBouquin, J. et al., 2005](https://www.aanda.org/articles/aa/full/2006/18/aa4258-05/aa4258-05.right.html?display=full)
* Astronomical Interferometry on the Moon. [Burke, B., 1985](http://adsabs.harvard.edu/full/1985lbsa.conf..281B)
# Method
### Site selection
The asteroid belt is relatively sparse. Estimates of the number of asteroids over 1 km range from [1 to 2 million](https://solarsystem.nasa.gov/planets/asteroids/indepth). Gladman, 2009, finds the power law scaling of asteroids with size at in this range to be -2.5; so the number of asteroids is $N \propto r^{-2.5}$; this would put our 100 m asteroid estimate at 300-600 million.
The inner part of the asteroid belt is [distributed](https://en.wikipedia.org/wiki/Asteroid_belt#/media/File:Main_belt_i_vs_a.png) between approximately 2.2 and 3.3 AU from the sun, at an inclination up to 20 degrees. This corresponds with a torus with major radius 2.75 AU and minor radius 0.55 AU. This gives a volume of about 16 cubic AU, or $5.5\times10^{25}$ km$^3$.
For an assumed 500 million asteroids of 100m or more, this gives a density of $9.1\times10^-18$ km$^{-3}$; or, assuming a random distribution, an average distance between objects of 500,000 km; more than the distance from the Earth to the moon.
For objects over 100 m diameter, the density is as low as the density of moon-sized objects near the Earth. Since the Earth is in no great danger of being hit by the moon, our interferometer is not in particular danger of being hit or otherwise affected by another asteroid. For objects smaller than 100 m diameter, these are approaching the size of objects that we do move in space. If we are able to bring a large telescope installation to the asteroid belt, we should be able to deflect an asteroid of this size.
### Vibration management
A space station will not have the optical resolution required due to vibration. I share some vibration information from ISS in this [post](https://worldbuilding.stackexchange.com/a/67707/23519). The sort of vibrational stability needed to resolve a milliarcsecond with a 100m baseline receiver is aobut 0.5 $\mu$m; the ISS vibrates with an amplitude of about 4 mm.
How can we get a stable enough platform? Well, the Earth is obviously stable enough for giant interferometers like LIGO. The asteroids we need to pick will be intermediate in stability, since they are between the size of the Earth and the ISS. I could not find reasonable information or calculations to perform regarding the stability of a platform built on or into an asteroid, but we will assume that an asteroid must be selected with the proper characteristics of a stable platform. I would imagine we would chose an asteroid of 1km or greater diameter, if possible. The larger, the more stable.
### Directing the interferometer
If you have two points on opposite sides of the asteroid belt, then it makes sense that you will not be able to resolve the objects which lie in the plane of the solar system. There will be too much interference from other asteroids, or the sun or what have you.
The solution is simply to restrict your observations to one or the other hemisphere. For example, you can build your telescopes on one side of the asteroids so that nearly the entire celestial northern hemisphere (roughly the same northern hemisphere we would see from Earth) is visible to both telescopes at all times. Since most of the mass of the solar system is in the plane (ok, most is in the sun, but the rest is in the plane), there should be little in your way. There are many asteroids in the main belt with high orbital inclinations, so you would have to account for this in the site selection phase, and perhaps make some efforts to move a few of them out of the way.
Now, a key to stabilization will be to rotate the asteroid. This will take some time and a lot of fuel, but by slowly rotating both asteroids at exactly the same speed, you will both improve stability of your optical platform, and provide a constant motion for each telescope relative to the other one. Again, this serves to restrict your field of view somewhat to one or other hemisphere.
Lastly, if you have enough money, you could mount separate telescopes on both sides of the asteroids, so that you can look at the northern and southern hemispheres at the same time with separate instruments. There are two ends of the axis of rotation, so you can be looking at both sides at once.
### Multiple telescopes
If you want non-trivial frequencies with a non-trivial band, why not use a non-trivial number of telescopes? Since we're setting up shop on an asteroid of at least 1 km radius, and preferably more, there should be room for a variety of instruments.
The Hubble telescope has multiple instruments but only one mirror. Without going into specifics of what frequencies you are interested in, I think it is plausible to have two sets of instruments, one in the visual and near-infrared range, and another in the UV and/or X-ray range, each with their own optical mirror to focus on a variety of specialized instruments.
### Position and timekeeping
The solution to your issues with combining the pictures from so far apart is to use high precision stationkeeping and timekeeping devices. For this purpose, a fleet of satellites similar to Earth's GPS system will do.
For example, a satellites could be set up in two orbits, one inside and one outside the Asteroid Belt. You will need enough satellites that at least two in each orbit are visible to each telescope observatory at all times. I believe that you will only need three in each orbit, but possibly four.
Using these satellites like GPS, if you are getting four signals at the same time, you can calculate your position accurately in fourspace (x, y, z, t). The principles of operation are the same as [GPS satellites](http://www.physics.org/article-questions.asp?id=55). These satellites already use atomic clocks and relativity adjustments for accuracy, so they will provide the location, direction, and timekeeping metadata to accompany each picture taken by your telescopes.
### Post processing
With accurate enough 4-d orientation in spacetime, it becomes a relatively trivial matter to combine the pictures at a later time. The pictures and their metadata can all be beamed back to Earth for post-processing (the way that our deep space probes like New Horizons do now).
# Conclusions
The only part of this which is not within our current technological capabilities is the heavy lift of dragging 100 m optical, IR, or X-ray mirrors 3 AU away to a suitable asteroid.
The 'image' combination technology is not much different from what [LIGO](https://en.wikipedia.org/wiki/LIGO) is using for its disparately spaced detectors (Washington state and Louisiana); the only difference our orientation satellites need from GPS satellites is more power to push their signals over AU distances. And the telescopes in whatever bands you are interested in don't have to be any more powerful than the best we have on Earth (although, they do need to work in a vacuum, I suppose).
] |
[Question]
[
Welcome to this fun little series, that will explore all the classic sci-fi tropes and attempts to turn them into reality with the **ALMIGHTY POWER OF SCIENCE!**
Today's topic is:
## The Force Field
[](https://i.stack.imgur.com/JDgIX.jpg)
---
## What do we know?
Force fields are a common trope in sci-fi, from Star Trek to Star Wars, just around everywhere. We ging to have a hard time, finding out their exact properties as they vary by franchises, however, what seems to be general in their attributes are:
* ***They are capable of deflecting or dampening at least one attack-type***
* ***If the power of an attack breaks it, it can be regenerated relatively
quickly, assuming, that the user isn't dead yet.***
* ***It can deflect attacks, even if the user doesn't perceive where they
are coming from.***
I think it's enough, now let's work out things from here.
[](https://i.stack.imgur.com/nEr9r.jpg)
An ~~angle~~ ~~gundam~~ angel using it's A*u*T*ism* Field. (source: Rebuild of Evangelion 1.0: You are (not) Alone)
---
## Our proposal
This solution is the combination of various answers from all across Worldbuilding StackExchange.
**What's our greatest problem?**
Kinetic energy. It's f@@cking hard to protect against it, but why?
[](https://i.stack.imgur.com/X5KdS.png)
*If that thing breaks loose, we're boned.* ([source](http://stardestroyer.net/Empire/Tech/Shields/Impact.html))
**A physical law**, delivered to you by Newton himself:
>
> When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
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>
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Ouch. That means, that no matter what, without deceleration nor distribution of force, you gonna feel that rock hitting you. But there is a way to dampen it.
>
> F=ma
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and what's more important:
>
> p=F/A
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So, we need to:
* ***Decelerate the projectile.***
* ***Distribute the force over a larger surface.***
In more extreme cases:
* ***Make the projectile explode, then decelerate the fragments.***
* ***Or [redirect](http://tvtropes.org/pmwiki/pmwiki.php/Main/BulletDodgesYou) the projectile ([or the user](http://tvtropes.org/pmwiki/pmwiki.php/Main/DodgeTheBullet)).***
---
## With that being said, what's our plan?
The plan is to overkill (over decelerate) the projectile. We can earn this by using the [answer](https://worldbuilding.stackexchange.com/a/12527/32097) JDlugosz, and using out the flux pinning to pin these layers to the user's suit:
[](https://i.stack.imgur.com/pXkii.png)
[](https://i.stack.imgur.com/LdaVH.png)
As you can see, the proposed shield:
* Decelerates the projectile a bit with the spongy material.
* Decelerates the projectile, when the magnetic fields and the
conductors are moving.
* Spreads ou the impact force over the largest possible surface...
* ...Which is also has a few layers of the spongy material.
* Then the superconductor returns the parts of the layer to their
original position, the framework repairs itself, ready to take the
next wave.
The shield also could just simply use laser and thermal shock to break apart it's target to manageable pieces, then decelerate those.
**What about the other damage types?**
* **chemical:** There are many inert materials, I can easily incorporate
them into the shield.
* **heat:** Still a problem (especially with continuous plasma beams).
* **ionizing radiation:** [yay](https://youtu.be/CLY-FMxsb2U?t=855) (though the suit might need a container and an in-built toilet for the stuff.)
* **non-ionizing radiation:** Reflective layers or if microwave, then
heatsinks.
---
## **Now, I want to ask you few things:**
***Could this work, if not then why?***
***If you want you can make improvements for this shield concept.***
---
*And remember: I want this series to be used by pretty much anyone, like a base full of working and fledged out shield concepts.*
---
## Addendum: #01
*(can be discussed in the comment section)*
Deactivating the shield seems a bit tricky, but here is a possible solution:
If we would cover the conductors with something that insulates it from magnetic fields and can be retracted, when switching to defense mode, then we could ensure, that the user wouldn't be slowed down when changing the position of the conductors and magnets.
The other thing would be making the framework loose and flexible and what's more important, movable to other points (with having "joints", that can break when overstressed without shattering and can be detached, and moved to a location, where it's not in the way) so then we can squeeze our shield when doing things, also it would be possible to lower our defenses in order to pull a lever, attack etc...
[Answer]
**Plausible Force Shields.**
Force fields can be achieved through a combination of multiple systems targeting a specific type of threat. As none of the following layers are connected directly to host/ship they do not necessarily experience any ill effects Newtons 2nd Law. Even in the most harsh situations they just have to move with shields.
The outer layer consists of a supercharged plasma window, shaped into a dome or sphere by electromagnetic fields. This is hot enough to vaporize most incoming metals. A static supercharged plasma window for general purpose usage, and a manually controlled short range plasma window for directional threats, to be used as shields.
A secondary layer underneath contains millions of curved laser beams, producing a high-energy web that captures projectiles fast or powerful enough to bypass the plasma window.
A third layer consists of a "lattice" made from trillions of carbon nano tubes. These microscopic structures are woven together in an instant, forming a diamond-hard shell repelling objects missed by the other two layers. If necessary, this can be extended to cover a larger perimeter, at the cost of decreased strength. Conversely, it can be reduced in size to provide an even denser and more durable barrier. You can propagate the force around the host if necessary, without any disturbance to them.
The layers described above can protect against the majority of bullets, bombs and projectiles. However, they are almost useless against lasers. A fourth and final layer takes care of this problem. This uses photochromatic particles, which change their properties when exposed to laser light, effectively neutralizing most directed-energy weapons. Similar to sunglasses that changed color when exposed to sunlight.
[Answer]
Couple possibilities:
**[Photonic Matter](https://en.wikipedia.org/wiki/Photonic_molecule)** - It is possible to take photons (light), which are massless, and bind them together so they behave as if they have mass.
It may even be possible to arrange the photonic molecules in such a way within the medium that they form larger three-dimensional structures (similar to crystals).
If science was able to produce this at high enough densities, it may be possible to use it to slow/deflect other forms of matter.
**[Dark Matter](https://en.wikipedia.org/wiki/Dark_matter)** - The name refers to the fact that it does not emit or interact with electromagnetic radiation, such as light, and is thus invisible to the entire electromagnetic spectrum. Although dark matter has not been directly observed, its existence and properties are inferred from its gravitational effects such as the motions of visible matter, gravitational lensing, as well as its influence on the universe's large-scale structure.
One theoretical source of dark matter are [Strongly Interacting Massive Particles (SIMPs)](https://en.wikipedia.org/wiki/Strongly_interacting_massive_particle). If they actually exist, and if they could be produced artificially through super advanced science, then making a shield that can absorb kinetic energy could be possible.
As Dark matter does not interact with EM radiation in any way, this would be somewhat useless against lasers, unless the gravitational effects were enough to cause diffusion through lensing.
**[Utility Fog](https://en.wikipedia.org/wiki/Utility_fog)** - Microscopic nano manufactured machines with arms that can extend out and link with each other in order to form structures. When needed they can lock together to form a solid barrier and absorb kinetic energy.
] |
[Question]
[
The year is 1970, and the hooded man sits in the very back of an abandoned building with a mysterious object in his hands.
A month ago, he had a name, a life, wishes, dreams, and aspirations. Then everything changed when he stumbled across a struggle between four-dimensional creatures during a hiatus in the mountains, and one of them dropped an artifact and left it there.
It contained a set of instructions that changed its language based on the reader as it was woven of handwavium and the ink was processed from a liquid form of [lalalaicanthearyouium](https://worldbuilding.stackexchange.com/questions/34279/building-a-bridge-to-the-stars).
*`Think of an entity's given name while holding the artifact and looking at an image of any form of the entity or the entity itself and that entity will perish. Use the dials on the artifact to control how the entity will die and that person will die immediately.`*
He looks at a photo. We see a flicker of... someone. A terrorist? Or is it a Prime Minister?
---
**With this artifact, a real life [Death Note](https://en.m.wikipedia.org/wiki/Death_Note), how can this man maximise his influence over society and how could he keep getting away with it without being identified?**
Some things we know:
* He acts based off what he believes is best for humanity. He'll kill a serial killer or terrorist on the loose but he'll also remove a person from power if he thinks it's best.
* He's a middle-aged American.
* The instructions are true to the letter. Without a person's name **and** image, it doesn't work, and the effect is immediate without possibility of delay.
* He is not wealthy at all. Yet.
* No one has caught on to a pattern, but if he's not careful and doesn't take the necessary steps, they're able to with some Sherlock Holmes finesse.
**Extra specifications for less broadness:**
* He wants to build up control over the world and help push it along to a better state of technology, peace, and all around good enough to [impress aliens](https://worldbuilding.stackexchange.com/questions/34599/benevolent-aliens-will-help-us-all-on-one-condition-can-we-end-all-wars).
* For the sake of this question, many people would not be happy with his decisions. Say a pattern emerges and people of perfectly good health are dropping dead. People start realising that it's only when a person's name is publicly released or available and that person's face has shown up in newspaper clippings or on television. Who knows who's next on the chopping block? And if they do detect him, his methods still take life away. It's not by the book.
* Good answers require that he a) maximise his chance of remaining undetected or not captured (remember, it starts from 1970) but also maximise his influence over the world.
[Answer]
In classic detective fashion, let's look at means, motive and opportunity for any patterns that could be used to track down the hooded man and how he could prevent or delay discovery.
## Means
This one is fairly obvious. People are going to notice a string of people dying to "sudden cranial explosion syndrome". On the other hand, stating "Person X will die of natural causes" will delay the discovery of any pattern for a very long time. A long list of diseases (heart failure and cancer being the most common in the 70s) may work equally well.
Note: It's hard to even say it, but the hooded man should experiment a bit on random unimportant people. If "X gets hit by a train" causes that to immediately happen *inside* X's corner office on the 42nd floor, that's going to complicate things. Also, can bystanders be affected?
## Motive
"Who stands to gain from person X's death?" is the second way to discovery. If the hooded man's competitors for a promotion all drop dead inside a week, even the densest investigators are going to question him. They might also drop dead, but this just escalates the situation until a SWAT team of masked and nameless people busts down the door and kills the hooded man.
If the hooded man is motivated by personal gain, he has to be *very* careful to only use the artifact a minimal number of times (and this already assumes he is immoral enough to use it at all) and preferably in an indirect way. Rather than killing of a competitor, he might have the competitor's boss's corporate sponsor over in the head office meet with a traffic accident.
If the hooded man wants to affect the world at large, the risk is very low as long as he targets well-known (bad) people in far away places that have no personal link back to him. Unfortunately, any successor may be worse and if a string of people dies, smart investigators may start to establish a pattern. If they all die during CNN breaking news broadcasts, including a few only shown in the US, the authorities might start laying a trap.
## Opportunity
In this rather unique situation, the opportunity merely consists of having a picture or a name of the target person.
Actually, a picture is pretty much required, because many people may share a name. If our hooded man tries to "fix" North Korea by killing Kim Il Sung, another few hundred people of the same name will drop dead if he doesn't use a picture. That is so unexpected that intelligence agencies all over the world will be on the lookout for any more occurrences. Each accidental multi-kill will draw the net closer.
On the other hand, getting pictures of the intended targets would not be nearly as easy in the 70s as we've come to expect in the age of Facebook and Instagram. Newspapers would be the primary source, as back then even borrowing the wrong book from a library would arouse suspicions. Having a picture of Kim Il Sung would be enough to be branded a communist spy, let alone collecting a whole bunch.
Discovery could be delayed by handling and possessing the pictures for as short a time as possible. Don't cut them out of newspapers, keep all newspapers if you have to, not only the issues/pages with persons of interest. Burn any separate pictures asap and above all, don't keep a diary of all the evil things visited on the victims.
Spoiler alert:
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> The hooded man dies by the artifact while trying to kill an investigator whose picture (and name) turns out to be an edited photo of the hooded man himself.
>
>
>
[Answer]
First, getting away with it is not an issue. The mechanism (supernatural assassination) is simply not recognized by modern society as possible, so there is no recognition of what's going on. As long as the hooded man resists the temptation to use his device up close and personal, he should have no problem.
The hooded man will therefore have to restrict his activities to public figures, eliminating leaders whose policies he doesn't agree with. In the long term, he may have some success in weeding out the worst (from his point of view) or at least the most effective individuals.
Making money with this device is certainly possible, by renting out as an assassin for hire, but this is a very risky proposition. Convincing a potential client of your effectiveness has the possibility that you're talking to an FBI agent or some such, and gaining entrée to a criminal organization is likewise iffy. The idea of working as an anonymous killer is pretty much a matter for bad movies - criminal organizations like to see who they're working for, and sooner or later they leak.
] |
[Question]
[
I am doing some work within the setting of the *Exalted* tabletop role-playing game. In broad brush strokes, the defining feature of the world is the five elemental poles: Water (west), Wood (east), Air (north), Fire (south), and Earth (center) – the setting is on a plane rather than a globe, hence the "center" pole.
The Pole of Earth sits on an island roughly the size of Russia, and is expressed by Mount Meru (alternately called the Imperial Mountain). Similar to the Mount Meru in Hindu/Buddhist mythology, the Imperial Mountain has absurd dimensions: the setting information notes that the ancient city of Meru being located halfway up the mountain, 300 miles above the ground.
This is the only dimension for the mountain explicitly given. However, assuming the mountain's icon on the world map is to-scale, it would have an approximately 470,000 square mile base (larger than Greenland).
This startling geography naturally causes some problems. When the sun "rises," the entire world would enter "day" at (roughly) the same time. The Imperial Mountain should, then, cast massive shadows across the western ocean in the morning and across the eastern lowlands and forests in the afternoon. Winds around the mountain would cause all kind of havoc with temperatures and precipitation. I'm sure there are other major effects that would be caused by the giant spire of rock in the middle of the world, but I don't have the experience in the many varied fields that would be required to detail all of the problems with a 600-mile-tall-mountain.
The standard answer to a conundrum like this in the *Exalted* setting would be that the gods or the elementals handle it. Natural phenomena like storms and earthquakes require a bureaucratic paper trail, and the sun itself is basically "the Death Star, decorated like the Taj Mahal" (to quote a post by one of the freelance writers of the setting); why not just have the celestial bureaucracy stick their collective fingers in the problem and fix it with magic?
My main problem with leaning on the gods is that it's boring to simply say "a ~~wizard~~ god ~~did~~ fixed it." The secondary problem is that in the "modern" times of the setting, *the celestial bureaucracy is broken:* gods take bribes, slack off on their jobs, etc. – Heaven even suffers from unemployment, these days.
**How could normal humans deal with the issue of a giant mountain causing world-ranging problems, without resorting to prayer or summoning supernatural entities?**
Only gods, elementals, the titular Exalted, demons, faeries, and certain powerful undead are directly capable of using magical powers. The best that a normal human may be capable of is some ritual-type magic, such as reading the future in the stars (and even that is going to be about as specific as a Magic 8-Ball).
Technology level is generally medieval (with the exception of rare magical artifacts and [ancient technology](http://tvtropes.org/pmwiki/pmwiki.php/Main/OlderIsBetter)).
[Answer]
I had to go look up what each region is roughly expected to be like. Noting that the plane is supposed to be [finite](http://en.wikipedia.org/wiki/Exalted#Setting), you homed in towards the problem with that hunk of rock, as far as I know it's impossible for there to be a cold icy North like there's supposed to be and a forest in the East. I can come up with complex scenarios to physically get either/or but not both. You are thus required to invoke pole-based magic.
As we are now invoking magic for weather you can get whatever you want from the system. As we have magic weather we might as well choose between uniform gravity and gravity-as-usual where you would feel more of a pull towards the center of the plane as you ventured towards the edges. With arbitrary magic atmosphere I see no reason not to magically mix breathable air up to any height. In fact I can't see any real reason for "space" to actually ever start. Certainly at some point the atmosphere wouldn't be bound by gravity but that's no reason for the "beyond" to be anything other that air.
---
Actually I just revised one of my scenarios and there is *The One* where you could achieve the necessary conditions realistically. You need a practically solid mountain range around the South and one separating the East and West on the topside of the plane (your center mountain) to set up [Orographic rain](http://en.wikipedia.org/wiki/Precipitation_types#Orographic) for the East's forests.
You would need a sun that orbits extremely low over the Southern end so that it causes the central mountain to cast a shadow over the North nearly all the time. You would also need the bottom side to be entirely flat ocean so the rain shadow effects have time to be canceled out and evaporation to occur for for the North.
Wind would continuously blow West and weather pattern would be unchanging from day to day.
Due to the low Southern sun and the constant Western wind it would become impossible to get lost pretty much everywhere. Your crazier weather all but disappears except in the north where ice crystals and crazy mixing from the dual rain shadows (your finite edge of the plain acting like mountains) cause intense storms.
So **"How could normal humans deal with the issue of a giant mountain causing world-ranging problems, without resorting to prayer or summoning supernatural entities?"**
* In crazy pole-based magic land they observe any pattern in the magic if they're there and exploit them, or stay as far away from each pole as possible if their particular effects are dangerous.
* In The One land you have guaranteed constant weather so you find a place you like and stay there.
---
**It was asked at what angle the sun should be over the South so I figured I'd flesh it out:**
It's worth noting you won't have seasons with this setup as calculated. You could have a "wobbly coin" for your plane relative to the sun to pull them off but you'd have to tune everything carefully to get season while still keeping the ice in the North and the desert in the South.
*Note that ALL references to distance are in regards to the Northern Edge.*
Alright, so the major cause for temperature changes is [insolation](http://en.wikipedia.org/wiki/Insolation). Ice has natural reflectance, so our target is enough shadow cover to get to `0 °C` and we'll assume a feedback loop takes over from there and drags it lower and stabilizes it.
$$\text{Temperature} = \sin (\text{SunAngle}) \times \text{SolarConstant} \times \text{PercentDaylight}$$
I'm not going to use the typical definition of solar constant here, mostly because we don't care, it's a raw solar heating number that gives a target base temperature.
Now the mountain is `600 miles` tall and based on looking on some *Exalted* maps I'm going to guess `~30,000 miles` average diameter for the plane.
Using trig you need that shadow to cast from `600` on one edge of the triangle to `15,000` on the other so we can cover the widest part of the north
$$\tan ^{-1} \left( \frac{600}{15,000} \right) = 2.3°$$
*(thats maximum sun height in the sky from the far edge of the North)*
This should also maintain the amount of shadow by sweeping equally across the North. Assuming `24 hr` days we have `12 hrs` of shadow time roughly equally distributed across the north. So subtracting, the North receives `11/24 daylight percent`.
In order to have the shadow sweep across the entire North our sun's orbit radius must be equal to the radius of the plane. This is because as we head towards infinity the shadow from the mountain will actually spread across the entire top half of the map. And as we head towards a radius of zero it will tend toward a straight shadow behind the mountain...
Using our plane radius of `15,000 miles`:
$$\text{Distance} = \frac{15,000}{\tan(\theta\_1)}$$
The middle needs to be `25 °C` and the north `0 °C`.
Using kelvin to avoid `0 °C` in math:
$$273 = \sin(\theta\_1) \times C \times \left( \frac{11}{24} \right)$$
$$298 = \sin(\theta\_2) \times C \times \left( \frac{12}{24} \right)$$
Solving for $C$ since its constant:
$$C = 273 / \sin(\theta\_1) / 0.416$$
$$C = 298 / \sin(\theta\_2) / 0.5$$
Note that using similar triangles:
$$\tan^{-1} \left( \frac{\text{Radius}}{\text{Distance}} \right) = \theta$$
So:
$$\theta\_2 = \tan^{-1} ( 15,000 / ( (15,000 / \tan(\theta\_1)) -15,000 ) )$$
Where $\theta\_1$ is the angle from the North edge and $\theta\_2$ is the angle at the Center.
To achieve room temp at the middle of the plane we need:
$$298 = \sin(\theta\_2) \times C \times 0.5$$
To ensure a proper temperature in the North the value of $C$ must be:
$$C = 273 / \sin(\theta\_1) / 0.416$$
Combining with the proper temperature for the center:
$$298 = \sin(tan^{-1}( 15,000 / ( (15,000/tan(\theta))-15,000) ) ) \times 273 / \sin(\theta) / 0.416 \times 0.5$$
Solving for $\theta$$:
$$\theta = 0.785398°$$
Solving for Sun distance using similar triangles:
$$\text{Distance} = 15,000 / \tan(0.785398) = 1,094,200.5\text{ miles}$$
Using similar triangles again to get the angles for the North, Center and South:
$$\tan^{-1} \left( \frac{\text{Radius}}{\text{Distance}} \right) = \theta$$
$$\tan^{-1} \left( \frac{15,000}{1,094,200.5} \right) = \text{North} = 0.785397979°$$
$$\tan^{-1} \left( \frac{15,000}{1,094,200.5 - 15,000} \right) = \text{Center} = 0.79631297°$$
$$\tan^{-1} \left( \frac{15,000}{1,094,200.5 - 30,000} \right) = \text{South} = 0.807535595°$$
Solving for the appropriate $\text{Solar Constant}$ to get a `25 °C` Center:
$$C = 298 / \sin(0.79631297) / 0.5 = 42,884$$
Testing out our temperatures for the $\text{North}$, $\text{Center}$, and $\text{South}$:
$$\sin(0.785397979) \times 42,884 \times 0.416 = 244 K$$
$$\sin(0.79631297) \times 42,884 \times 0.5 = 298 K$$
$$\sin(0.807535595) \times 42,884 \times 0.5 = 302 K$$
**So the *extremely low* angle is less than `1°` high in the sky.**
Note that the South will have increased heat due to the rain shadow and the North is freaking cold and actually colder than that because the ice will reflect more.
[Answer]
I'm going to assume 'earth' for the point of atmosphere and what this mountain would generally be.
About 80% of the mass of the atmosphere is within the first 9-17 km (thicker at equator) of altitude. At 50km you enter the mesosphere which is the top end for clouds (and these are rare and a special type). Keep going up...low orbit satellites are found around 180 miles (300km) in the middle of the Thermosphere (thermosphere will hit temps of 1500 celcius, but it'll feel cold because it's near vacuum here)...which I guess means an advanced society should leave communication satellite wreckage less than 1/3 of the way up this mountain.
At 300 miles above earth where we find the ancient city (by your post, I went with the 300 miles is where the city is and not the top of the mountain), the pressure is low enough that the pressure within a human hand will start to expand the hand to several times it's natural size (there's a brutal online video for evidence of it...some poor guy jumping out of a balloon had his glove come off). The air will not support life at all (oxygen thins out and you're mostly in hydrogen and nitrogen at this point). And you should be relatively close to weightless at this point.
Several times during the day, an inhabitant of the ancient city of Meru should be able to look out the window downwards about 50 miles to see the international space station float by (ya, the ISS is around 250 miles up). Standing at the top of this 600 mile mountain should mean you've successfully broken out of the earth gravitational pull and you should be able to throw rocks into the sun. Weather would be fun as you're starting to hit the Van Allen radiation belt...would be nothing but electrical storms.
This of course means the mountain cannot really be explained without some form of magic...with the rotation of the planet, there's a good chance the top of this mountain should break off into space and start floating around as it's own stellar body. A volcanic eruption should be shooting lava into space.
In more practical terms...I think this is a mountain of myth and lore. Standard people would barely be able to survive (atmosphere limitations) even at the lowest base points of this mountain. It'd be a 'dark' area where no life is really capable of inhabitting and as such would likely be the source of much lore (creatures of the mountain?). Creatures that can live on this mountain have to do so nearly void of oxygen...might get some interesting near alien species of monsters cropping up. It would be a giant impassible black hole on most human maps.
] |
[Question]
[
I am designing a world in which the biological solvent is an ammonia-water mixture and need help finding out which blood pigments (Hemoglobin, Hemocyanin etc.) would be immune to the negative effects of ammonia. I couldn't find anything about this specifically on google, so I've decided to ask.
[Answer]
I've come to the conclusion that none of the blood pigments we have on earth have immunity to ammonia poisoning. In fact, an ammonia-water solvent with any significant amount of ammonia isn't something that is possible in an organism unless they have completely different biochemistry from us (though our bodies do produce very small amounts of ammonia, it is processed into urea in the liver). Ammonia, when mixed with water, becomes ammonium hydroxide. Ammonium hydroxide is a caustic. Caustics destroy proteins, as shown [in this link](https://www.sciencedirect.com/topics/medicine-and-dentistry/caustic-agent#:%7E:text=Caustic%20agents%20are%20chemical%20and,resulting%20in%20deep%20tissue%20penetration).
Basically, in order for an ammonia-water solvent to be possible, your lifeforms would need to have completely different biology from anything we have on earth.
However, that is from a purely scientific standpoint. I don't know the ins and outs of your world, or how scientifically accurate you want it to be, but you could create some component of a lifeform that counteracts the toxicity of ammonium hydroxide. Ammonium hydroxide is a fairly alkaline chemical, which is in large part the reason it's a caustic, so having another acidic chemical could help to counteract this. Or you could have a chemical that prevents ammonia and water from creating ammonium hydroxide.
These are just suggestions, however, and you *can* choose to ignore the chemistry if you want. This is worldbuilding, after all, not a science convention.
] |
[Question]
[
It is known that when a planet orbits very close around its star, the tidal effects will soon (on an astronomical scale) force the day and the year of the planet to have the same length, making the planet show the same face to the star (let's ignore the possibility of orbital resonance). So the body will be tidally locked to its star.
So, if the planet was born from the same gas cloud as the star, it will rotate along an axis that has (almost) no tilt with respect to the orbit.
But what if, for instance, a star captures a rogue planet in a close orbit or an impact with a massive body reorients the rotation axis of a close planet? This planet now has an axis of rotation that is almost 90° tilted with respect to the orbit plane (in other words, the axis is not perpendicular, but parallel to the orbit plane).
So, my question is: what will likely happen in a situation where a planet is tilted of 90 degrees with respect to the plane of its orbit, and is very close (like Mercury, or less) to its star?
* Nothing? (the planet in spite of the proximity won't experience any change in its rotational dynamics, experiencing particularly extreme seasonal variations, as Uranus)
* the tidal effects will slowly force the rotational axis to align to the perpendicular of the orbit plane (and eventually tidal-locking it to the star)?
* the tidal effects will slowly reduce the rotation of the planet, gradually stopping its rotation?
* something else?
[Answer]
**the tidal effects will slowly force the rotational axis to align to the perpendicular of the orbit plane (and eventually tidal-locking it to the star)**
This will, however, take a very long time--hundreds of millions of years, up to possibly billions, depending on precise details of the planets composition, initial spin rate, and exactly how large its orbit is.
The most obvious short-term effect will be slow precession of the planet's axis as tidal effects apply off-axis torques. Depending on which way it spins, this will result in each pole pointing towards the sun either slightly less or slightly more than once per sidereal year.
Over the very long term, the planet will end up tidally locked, with some sort of spin-orbit synchronization and a spin axis close to its orbital axis--but, its initial spin angular momentum can't just disappear. Rather, it will have been transferred into orbital momentum along the way (just as, for example, the Earth's spin angular momentum is slowly being dumped into the Moon's orbital angular momentum by tidal interaction), resulting in a final orbit that is inclined with respect to its initial orbit.
] |
[Question]
[
A creature in my story was largely inspired by the xenomorphs of the Alien franchise. In wondering how long it would take one of these creatures to grow from conception to maturity, I decided to look at my original inspiration which only posed more problems. Xenomorphs develop insanely fast! Growing from an egg to a nymph in a matter of hours and from a nymph to an adult drone in maybe days. So my question is as stated: How fast could a large creature feasibly grow and how much would it need to eat?
[Answer]
* **How fast could a large creature feasibly grow?**
[Growth](https://www.britannica.com/science/growth-biology) & more specifically [Cell growth](https://en.wikipedia.org/wiki/Cell_growth) is what your asking about here.
>
> Growing from an egg to a nymph in a matter of hours
>
>
>
That given the size of the [alien](https://www.youtube.com/watch?v=BHSf7MXTlKM) you reference that pops out of the egg is perhaps the most implausible part of the the thing as growth of embryos in animals is not pounds or ounces per minute or hour but rather cell divisions per "x" period of time, & you start with a single cell.
>
> and from a nymph to an adult drone in maybe days
>
>
>
While this given the [starting size](https://www.youtube.com/watch?v=y-sBROXalU4) of stage in it's life cycle when it bursts from someones stomach is perhaps more plausible, if we assume a level of cell division comparable to the early stages of cell division in a fetus rather than in juvenile animals after birth.
>
> [Duration of the Cell Cycle](https://www.sparknotes.com/biology/cellreproduction/cellcycle/section2/) "Certain fly embryos sport cell cycles that last only 8 minutes per cycle!"
>
>
>
If we assume this is about as fast as it gets you could perhaps be looking at exponential growth (a doubling in size) every eight minutes.
* **and how much would it need to eat?**
A bit more than it's own body weight every eight minutes.
Which may be a problem for a large complex multi cell organism as
you'll need
1. An extremely efficient stomach & gut to absorb all those nutrients & calories fast enough.
2. An extremely efficient cardiovascular system to get it all to cells
that need it quickly enough.
3. Extremely efficient lungs for oxygen absorption to power the cell processes you're feeding.
Which may all need to be implausible efficient to sustain anything like that speed of cell division in large organisms, there's always hand waving though & you've not included a reality check tag.
---
The organism is going to need a certain number of calories just to sustain itself, I've had difficulty finding details on this so I'm going to have to extrapolate from Google searches on human statistics.
The [average calories needed by an adult male](https://www.google.com/search?rlz=1C1NHXL_enGB711GB711&ei=nilXXNiKBqWj1fAPktSyiAI&q=how%20many%20calories%20does%20an%20organism%20need%20to%20survive&oq=how%20many%20calories%20does%20an%20organism%20need%20to%20survive&gs_l=psy-ab.12..35i39.108449.108449..110809...0.0..0.74.74.1......0....1..gws-wiz.......0i71.kwUHVw9z_DI) is 1,800 calories a day.
The [average adult male weight](https://www.google.com/search?q=What%20is%20the%20normal%20weight%20of%20a%20man%3F&rlz=1C1NHXL_enGB711GB711&oq=What%20is%20the%20normal%20weight%20of%20a%20man%3F&aqs=chrome..69i57j0l5.1495j0j8&sourceid=chrome&ie=UTF-8) is 197.6 pounds
Extrapolating from those search results (which is of course wildly unsafe for all sorts of reasons, but all I have) gives a daily figure 9.1 calories per pound of body weight just to sustain itself.
---
*You should consider the above more along the lines of my showing my workings for a math question rather than my answer, gotta go for now so that will follow later, possibly a lot later, sorry about that :)*
] |
[Question]
[
I like to hear the sound of birds when I travel amongst my orbital and planetary habitats scattered around the outer system.
Most of these settlements are very densely populated - what you might call arcologies in your time - and this generates heat which renders most of them tropical and subtropical climes for the sake of energy efficiency.
The pleasant melodies of creatures like [scarlet-backed flowerpeckers](https://www.youtube.com/watch?v=lUekaC86jtU) and [bulbul](https://www.youtube.com/watch?v=Ez4DntI_cEs&t=98s) birds, you know the kind of thing, would be perfect for such an environment. [But you may have seen the feeds](https://www.youtube.com/watch?v=w4sZ3qe6PiI), birds - like most animals - don't enjoy microgravity too much.
What kind of changes might we expect to see bird species undergo in order to live comfortably in the low- and microgravity conditions of my habitats? More importantly, are any of these changes significant enough that we would see drastic overall changes in bird behaviour (e.g. hopping on surfaces rather than flying)?
Asking for my biotech folks.
[Answer]
I am going to assume that these environments have atmosphere since flight let alone sound would otherwise be impossible.
**As for flight in zero G**
As long as pressure remains the same it might be possible that a bird could mentally adapt to zero g and learn how to fly (would be an awesome experiment for NASA). In order to achieve flight, simply put, you need to create a pressure differential between the top and bottom of the wing. Gravity doesn't necessarily control this interaction, though it does influence it heavily terrestrially. One major way gravity plays a role in birds flight is it defines an up and more importantly a down. The downward pull of the birds mass is energy that is fed into its flight. The wings convert that energy into a pressure difference (gliding).
I'm not sure the loss of that energy totally forbids flight in pressurized zero-g (if it is even called flight at this point, more like swimming). If they can figure out a way to gain directional motion they could then theoretically re-learn how to "fly". In terrestrial flight, gravity ultimately is a negative energy that depletes the system.
Physiologically they wouldn't need wings as large as they have since gravity is no longer pulling them to the ground. If anything they'd probably be better off with highly dexterous fish like fins.
[Answer]
As long as their is a dense enough atmosphere, there is nothing preventing birds from flying, even in micro gravity.
Technically they would not really be flying, it would be more like "swimming"
They would be subject to the usual problems associated with micro gravity (bone density problems, blood circulation problems etc...).
[Answer]
There are a series of genetic modifications that need to be tested somewhere before they are applied to permanent human residents of any place outside of the Earth. Humming birds will face the most problems, and they will refuse to mate while songbirds will probably become duller as there may be a lower light environment, they may have to rely on song for courtship and communication. The 700 nm range of lights for the plants will often leave the habitats cast in a red glare. This light too will keep it warm. Some of the birds such as the Scarlet may become brighter and show more contrast in color with larger feathers for visual displays... I agree with fish finned sparrows. Perhaps more hopping or jumping from branches and the most of the wing beating will be reserved for instinctual dipping and diving. Pigeons roll a certain way in flight, determined by their genetics, and two birds will consistently display different behavior..... Many species will find independent methods of coping, adaptation or loss... Water in the air I imagine will counter many of the lift issues, swimming, especially when moving down or in-system, depending on gravity source. Consider Larry Niven's SmokeRing for effect.
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[Question]
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I am working on the realism of a fictional planet which has an average temperature lower than that of the Last Glacial Maximum (LGM), and possesses a single large supercontinent rather than distributed landmasses.
My research has indicated that Hadley Cells retreated equator-ward during the LGM, which would place the Subtropical Ridges closer to the Equator. I am curious what is likely to occur on a planet that is even colder than that? Would the Hadley Cells disappear entirely? What happens to the Subtropical Ridges and their accompanying deserts in such a case?
For reference: Hadley Cell Retreat - <https://journals.ametsoc.org/doi/10.1175/JCLI3766.1>
[Answer]
I'm not a climate scientist and this may not be much of an answer, but I'm hoping some of the sources I've found from quick searches online might prove useful:
* The Abstract of the 1987 paper "[Components of the ice age circulation](https://pubs.giss.nasa.gov/abs/ri03900p.html)" seems to indicate weakening of the Hadley cells due to "altered sea surface temperature patterns", and "the poleward extent of the Hadley cell and the zonally averaged jet stream show little difference from current climate values" which I take to mean that the size of the cell is the same.
* The book "[The Hadley Circulation: Present, Past and Future (Advances in Global Change Research)](https://www.barnesandnoble.com/w/hadley-circulation-henry-f-diaz/1101676679)" might be the best starting point for understanding Hadley Cells during glacial periods. Based on its summary, it seems to cover models of past climate conditions using known paleoclimatic records and is presented as a "fundamental reference work" for this area of research.
* I'd like to mention that most modern research is geared towards understanding man-made climate change and the effects of general warming trends. Quite the opposite of research that covers glacial periods. Most likely very little computer simulation time is allocated to historical, glacial research. As such, very little material will be available that covers your specific scenario.
* You may want to look at data concerning even older ice ages. It's likely there were even colder ice ages that mimic the conditions you are looking for. If that is the case, there should be literature out there describing the climate conditions of Earth at that time.
I hope you find this small bit of information helpful!
[Answer]
**Heat** is just a word for *random particle movement*.
A normal atom moves somewhere, until it hits another atom and moves in another direction. Most atom do. When your heating up this atom gets faster and hits the next atom with more speed and gets bounced back with more speed.
Heat means the particles are getting so fast that chemical bindings could get disrupted and particles run crazily fast.
**Cold** is just a word for lesser speed of the particles.
At 0°K or -273.15°C the [absolute zero](https://en.wikipedia.org/wiki/Absolute_zero) stands, meaning no more particle speed.
TL;DR
At the absolute zero no particle moves, meaning no more wind and no more Hadley Cells at all
Hope it helps :)
] |
[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.
By Colonies 'in' the outer solar system I mean the various moons and space stations past the asteroid belt.
Currently the Hegemony has established bio domes, mining stations, and a few large scale space colonies either on the moons of the outer planets or in close proximity (as well as some Centaurs like 2060 Chiron), but heating these worlds through mechanical means (space heaters) is expensive. If they could find a way to use natural systems already in place it would save them trillions of tax payer dollars.
Now my question is: How would you heat these colonies (the moons themselves) by using or manipulating natural systems? Is there a way, for example, to somehow channel or amplify solar energy, make use of Jupiter's radiation belt, or anything else I haven't thought of?
Note: This is in the context of later terraforming the colonies (in some cases. If its impossible to terraform a certain moon you can just skip over it when answering this question) so the temperature should be at least survivable with limited equipment (arctic temperatures would be the minimum temperature).
[Answer]
**Geothermal heat.**
Any large body will encounter frictional heating - the descent of mass towards the core liberates kinetic energy as heat, and this heat is trapped within the body to a greater or lesser degree. This is true for any sizeable celestial body. Consider Luna:
<https://www.space.com/18175-moon-temperature.html>
>
> The moon has an iron-rich core with a radius of about 205 miles (330
> km). The temperature in the core is probably about 2,420 to 2,600 F
> (1,327 to 1,427 C). The core heats an inner layer of molten mantle,
> but it's not hot enough to warm the surface of the moon. Because it is
> smaller than the Earth, the moon's interior temperatures don't climb
> as high.
>
>
> "It's not as hot [as Earth's interior] because the moon is smaller —
> hence its internal pressure is also smaller," NASA planetary scientist
> Renee Webber said during an online chat hosted by NASA. "The
> temperatures are probably lower than those of Earth
>
>
>
If you were on a dry and inert body like Luna you would need to install a deep reservoir with heat exchangers and then use water or some other fluid (ammonia? what is handy?) to move heat from the hot depths to the cold surface. Hot fluid comes up from the reservoir, drops off its heat in the living spaces, then circulates back down with its load of coolth.
If you were on a body like Saturn's moon Enceladus you might be able to use hot fluids naturally emerging from the depths, as we use natural hot water geothermal power on earth.
[Frictional Heating Explains Plumes on Enceladus](https://www.nasa.gov/mission_pages/cassini/media/cassini20070516.html)
>
> Tidal forces acting on fault lines in the moon's icy shell cause the
> sides of the faults to rub back and forth against each other,
> producing enough heat to transform some of the ice into plumes of
> water vapor and ice crystals, according to a new study published in
> the May 17 issue of the journal Nature.
>
>
>
The place where this might not work is very small metallic bodies like asteroids - they are not very big and so frictional forces are small, and they conduct heat because they are metal. They might stay cold thru and thru. You would need nuclear power on these.
[Answer]
**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.
Nuclear Fusion!
Has be done on earth, and is realistic! We couldn't *yet* achieve a effeciency of > 1, but we get closer, and once 1 is surpased the reaction will have been kickstarted and produce more energy than it consumes. Is it possible? Yass. Every sun does it every second of every day since suns existed and until there will be no more suns. It gives us kinda a lil bit of heat. It works like dis
H2 + H2 -> 2He + a lot of energy
14 MeV or 2,2x10^-12J
Sounds like not a lot but thats the result of fusion of 2 very H2 molecules
1l of H2 has 2.7×10^22 molekules.
this 1l gives us about 30 000 000 000J
30 GJ or about 8 MWh or about 1t of Coal worth of energy
Sauces:
<https://www.forbes.com/sites/quora/2017/04/12/contained-nuclear-fusion-on-earth-isnt-just-possible-its-been-done-repeatedly/#c5c0d414cfd5>
<https://en.wikipedia.org/wiki/Nuclear_fusion>
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[Question]
[
There is a lot of information on drying up a Mediterranean sized depression. However, there is not a lot of information on drowning such a large area or **what sort of habitats could exist before the flood**. eg before the [Zanclean flood](https://en.wikipedia.org/wiki/Zanclean_flood) drowned the previously dry Mediterranean region and ended the [Messianian Salinity Crisis.](https://en.wikipedia.org/wiki/Messinian_salinity_crisis)
In most scenarios the region would have to originally be mostly below sea level before the flood.
Most of my research around the Zanclean flood and other similar flood events have mentioned that it is typically in semi-arid and arid regions (ie previously dry) that these below sea-level depressions naturally dry up in. ie little rainfall or incoming river water. Which does make sense, as the water has to have gone somewhere...else.
I'm not focussed on how the depression would have become separated or rejoined to the larger ocean body. Just what sort of habitats are feasible before the flood, other than arid deserts?
Currently I am heavily contemplating drowning a large Mediterranean sized grassland and forest region, between 0 and 30 degrees north of the equator (equatorial region, lots of rainfall but also lots of evaporation). With a large dry desert above that.
**Is it possible to have any other habitat aside from arid desert in such a large-area depression?**
Affirmative answers should also address if and how this would be possible near the equator. ie Discounting a very large area of land subsidence, what natural features or processes would allow for an environment other than an expected lake or inland sea (BEFORE the flooding event)?
This is based off world but the planet has mostly earthlike processes and weather conditions.
Just incase, my planet does have a fair number of medium sized meteorites crashing down on it in the past, it can be very cratery in places. Back in prehistory, these impacts did do some substantial geological reorganising. I can increase/decrease this as necessary.
[Answer]
Yes, and the answer is nearby glaciation.
I checked the links you provided to refresh myself on the difficulties. Therefore, pardon me for doing more answering than explaining -- tell me if you think this works.
Non-arid means it has water and presumably plants to hold topsoil etc. Lower and presumably hotter than its environs means evaporation plays a key role. Salt does not evaporate with water and means that plants won't grow and soil won't stay. The only way to avoid salt without plants, water, and soil is going to be ridiculous (and skilled) winds, leaving only rocks, which is not what you are looking for. Water must be replenished and there must be a source which does not increase salinity.
Surrounding, or bordering on one side, and at higher altitude, a glacier can provide a fairly consistent source of fresh water -- consistent in decades or hundreds of years. That's long enough to build a civilization. You could even have the glacier irrigate *most* of your basin, and let the runoff with its accumulated continental salts collect in a deeper and hotter segment of the basin. Let "Death Valley" have its own salinity crisis -- now we have a locally complete water cycle.
Interestingly and poignantly (if unfairly) for SF terms, the salinity crisis could be a growing problem which must be confronted by the locals, only for them to be wiped out by a saltwater flood as the dam is breached.
When it rains, it pours. When it doesn't rain, it's worse.
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[Question]
[
I'm continuing to hash out the map of my world, using tutorials found on this site and elsewhere.
In [some tutorials](https://worldbuilding.stackexchange.com/a/989/37212) the starting elevation levels of a planet are treated pretty randomly, implying that while tectonic, volcanic, or eroding activity may be required for distinct features like mountains or gorges, larger scale elevation features (highlands, valleys, large plateaus) may be more up to the whim of the author, if rooted and justified by in the earliest shape of the planet.
Is this correct, or are there other constraining factors that I'm not aware of. As example, does this elevation map (with tectonic plates below it) included currently look realistic?
[](https://i.stack.imgur.com/w2B5o.jpg)
[](https://i.stack.imgur.com/QzszS.jpg)
Finally, and in general, is there anything else I should consider when making an elevation map?
[Answer]
Do you have an ocean? sea level as a starting point for elevation? If it seems pretty random, who would be checking to see whether your map is accurate or not? It's your world, afterall.
Try referring to contour/topographical maps. They do show elevation, but more detail than the 1st map you provided (which seems fine for a generalized/simplified world view. But assuming you will have more detailed maps of certain key locations, I would suggest using topographical maps showing contour lines (not necessarily only a contour map).
Examples (with links to images provided, also helpful information pertaining to reading maps, in any interest):
[](https://i.stack.imgur.com/Xgg9d.jpg)
*Shown to illustrate elevation with contour lines.*
[image source](https://www.rei.com/learn/expert-advice/topo-maps-how-to-use.html)
[](https://i.stack.imgur.com/nf6hV.png)
*Another example.*
[image source](https://archive.cnx.org/contents/7b8a84e5-0b3c-4e52-ab90-004506ecfec0@1/reading-contour-patterns-on-a-topographic-map)
[](https://i.stack.imgur.com/xnolA.jpg)
*More detail is provided. Note that elevation is marked along some lines.*
[image source](http://earthscience4reveryone.blogspot.com/2013/03/how-to-read-contour-map.html)
[](https://i.stack.imgur.com/7CgWK.jpg)
*Even more detail and information is provided, but still simplified*
[image source](http://www.wanderingvirginia.com/2012/05/virginia-topographic-maps.html)
[](https://i.stack.imgur.com/HaC1b.gif)
*A more aesthetically pleasing map, still provided with elevation markings, and much easier to read*
[image source](http://www.lib.berkeley.edu/EART/tour/topo.html)
] |
[Question]
[
In attempting to come up with a semi-reasonable method of intergalactic travel, I ended up conceiving a general method of FTL travel relying on [brane cosmology](https://en.wikipedia.org/wiki/Brane_cosmology) and the "bulk" being transversable in some way. More specifically, traveling from the brane through the bulk to another point on the brane acts like a highly non-linear map (in terms of distance traveled in the bulk's relationship to distance on the brane). The complexity involved in figuring out what path has to be transversed through the bulk to get to a specific point on the brane would make all but specifically mapped out routes too dangerous to attempt (sort of approximating a warp-gate network without actually having warp-gates).
My first question is whether or not this is at all compatible with actual theories of brane cosmology (this is really far from my area of expertise)? My second question is, assuming such travel is even theoretically possible, how much energy (order of magnitude) would be necessary to "breach" the bulk?
EDIT:
Having done additional research on the subject, it appears that the standard explanation for why additional dimensions are not apparent in brane cosmology is that material objects are the result of open strings and are "bound" to the brane on which our universe sits. As such, they cannot move orthogonally to the brane with which they are bound, which prevents them from interacting with the bulk (this also provides an explanation for the "weakness" of gravity; gravity is the result of *closed* string vibrations which are not bound to the brane and can leak out into the bulk). So, it seems that shifting from an open to closed string is necessary to interact with the bulk, which shifts the question to whether or not it is possible to have a string shift between open and closed states and if so how much energy does that require?
[Answer]
Yes your model for intergalactic FTL travel is sufficiently compatible with [brane cosmology](https://en.wikipedia.org/wiki/Brane_cosmology). The bulk is effectively a higher dimensional space with large, non-compacted dimensions. Effectively, this is something like the conventional science-fictional concept of a "hyperspace". A longstanding trope for attaining FTL travel in science-fiction.
For ease in traversing the bulk it may be best to assume its dimensions are simply a set of dimensions rotated away from the dimensions in our brane. Once a vehicle has accessed the bulk it would travel as if it was in "normal" space. You have assumed correctly that the distances traversed via the bulk will be complex and non-linear.
As for accessing the bulk, it may be easiest to assume this can be done by means similar to the creation of a [wormhole](https://en.wikipedia.org/wiki/Wormhole). The problem of accessing the bulk is now no more than that of making a wormhole.
Please note: Not all theoretical models of wormholes indicate they will collapse without using exotic matter to keep them open. This make intergalactic FTL travel so much easier.
Also, spacecraft need only arrive at a suitable point in our universe where they can create their wormhole to follow a "safe" path through the bulk to the galaxy that is their destination.
This answer has attempted to follow a similar set of worldbuilding rules implied in the question. Namely, selecting suitable plausible and genuine scientific concepts and using only sufficient hand-waving to make them fit for purpose in a science-fictional context.
] |
[Question]
[
**Closed**. This question needs to be more [focused](/help/closed-questions). It is not currently accepting answers.
---
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I'm writing (planning really) a fantasy novel based on the fae. My "scientific" explanation for them is that the fae realm is another planet accessed via wormhole. Since I wanted them to age normally compared to humans but *seem* like ageless beings, my dad proposed that the fae planet be on the far edge of a spiral galaxy with a black hole at the centre. The centrifugal force and velocity of the system moving would mean time was slower there yes?
So we have Earth connected via wormhole to Fae, and Fae with much much stronger gravity. So I have three primary questions.
1. What adaptions would a creature born on a planet with a lot of gravity have?
2. What would the effect be for a human on Fae/a creature born on a planet with high gravity on Earth?
3. Would there be any way for a human to survive on Fae short of magic?
EDIT: Apologies for multi-question post, my bad. Since this has been answered, is it okay to just close the post?
[Answer]
There is a computer game called *Mass Effect*. In the game there are alien species and one of them is called *Elcor*.
Elcor come from a high gravity planet like you explained and they evolved that way. They have rough skin, they move very slowly , they are very strong etc.
One of the things I find interesting about Elcor is: They have under developed facial muscles because most of the energy has to be spend against gravity , so they can’t do mimics and when they talk to humans , they verbally state their emotion by saying things like *laughing, angry,sad* after finishing a sentence.
[Here is the link to Elcor Wiki](http://masseffect.wikia.com/wiki/Elcor)
[Answer]
To answer your questions:
1. These creatures will be considerably shorter and stockier than humans. They will need thick, powerful bones and a strong heart and circulatory system. This will prevent gravity from simply pooling blood in the feet. Something else to note is that is will be highly unlikely for animals with exoskeletons to exist, as they'd be crushed under their own weight.
2.1. Without a pressure suit (similar to what pilots wear), humans might be crushed, die due to the aforementioned gravity issues and would generally have a hard time, due to the fundamentally different circumstances.
2.2 Astronauts suffer some serious ill effects due to micro gravity in space. Your Fae might have a similar response to the new environment
3. As I mentioned, they would need dedicated pressure suits and (if the gravity makes movement sluggish) some kind of exoskeleton.
Just to add to your scientific principles, the center of the galaxy is incredibly violent. Black holes give off more power through radiation in seconds, than our sun will in its lifetime. Also, You'd need specialized ships to travel worm holes, since they tend to be fairly violent to whatever tries to travel through
] |
[Question]
[
*Fullmetal Alchemist (2003)* features a giant (and I mean stupidly big) cave under a large and busy metropolis. Nobody is aware of its existence, which means that at least since the city's founding (let's say 150 years) there must have been **no subsidence of any kind.**
What little I know of cave-ins tells me this is rather unlikely, but for story-reasons I need to know how shallow I can make it before shit starts falling down.
* The cave is unsupported by any columns, and there is a very large space from the floor to the roof (perhaps 80-100m). The floor diameter is about 2-3km. [[pic]](http://fancaps.net/movies/Image.php?name=Fullmetal_Alchemist_the_Movie_Conqueror_of_Shamballa_Screenshot_1877&imageid=1834779)
* The cave was formed by wild magic, so the erosion/seepage found in karst caves need not be an issue.
* The time period is equivalent to **early 20th century**, and there is some light automobile traffic. My admittedly superficial research suggests that foundations in early 20th-century London were pretty shallow, so foundation depth is unlikely to have any impact.
* A river runs around the outskirts but not through it. Earthquakes are unlikely.
* The cave should run deeper than 4m (depth of [sewers](https://londonist.com/2015/10/how-deep-does-london-go))
In this admittedly improbable scenario, my question is: **What would be the minimum thickness for the cave ceiling so that, assuming ideal geological conditions, there is no risk of collapse under the weight of the city above?**
---
RESEARCH
>
> Sarawak chamber (Malaysia) is the largest known cave room (700x400m) with an unsupported roof span of 300m. No word on roof thickness.
>
>
> Son Doong Cave (Vietnam) has the largest known passage. According to Wikipedia, it is 4.6 km long, 80m high and wide over most of its length, but over 140m high and wide for part of its length.
>
>
> [A very interesting paper](https://www.researchgate.net/publication/222298871_Bearing_capacity_of_rock_over_mined_cavities_in_Nottingham) on the small (<11m) man-made caves in the sandstone under Nottingham recommends a depth of >50% of the cave width, which is pretty damn deep. This is for flat roofs in karstic limestone (stronger than sandstone).
>
>
>
[Answer]
The weight of a city is insignificant next to the forces that the cave has continually exerted on itself. Any safety factor that would definitely keep the cave from randomly collapsing in on itself, would make that little bit of extra weight negligible.
I'm having a pretty hard time [trying to interpret](http://www.stressline.net/lintel-load-span-tables-a-beginners-guide/) **stone lintel [load charts](http://www.kingstonelintels.co.uk/wp-content/media/King-Stone-Lintel-Load-Tables-May-2014-All.pdf)**, but given the type of stone and the length, you should be able to extrapolate a rough estimate. You'd better put a pretty large safety factor into it though, as any good load chart will be based off of independently tested samples.
Meaning, there's no way to be sure, and that's why things with a sufficient [safety factor](https://en.wikipedia.org/wiki/Factor_of_safety) "are purposefully built much stronger than needed for normal usage to allow for emergency situations, unexpected loads, misuse, or degradation (reliability)."
If this cave were under Chicago, it'd need to be [about 3000 feet](https://books.google.com/books?id=zuxZAAAAYAAJ&pg=PA53&lpg=PA53&dq=chicago+deepest+hole+drilled&source=bl&ots=j8CDB3lbYE&sig=tWgP9rvaYdF0kLezWve55o2oBOU&hl=en&sa=X&ved=0ahUKEwikudyW9ZjVAhVqzoMKHTGoCJYQ6AEIbjAM#v=onepage&q=chicago%20deepest%20hole%20drilled&f=false) down, or we'd have found it when we drilled wells. I'm guessing that if it weren't for modern seismologic surveys, there could be one down there right now...
I've stuck to your title and ignored most of your criteria, because *built on bedrock* and *there's no earthquakes* sounds like Chicago to me. Build your city basically right on top of the bedrock, and next to a nearly inexhaustible source of fresh water. Nobody likes drilling through bedrock, and if you don't need to for water, you won't.
---
>
> The SWL values in our load span tables are often subject to load ratios. These ratios represent the ratio of load that the lintel can bear as inner leaf to outer leaf. The ratios are different for the different applications.
>
>
> * 1:1 – Lintels supporting masonry only
> * 3:1 – Lintels supporting masonry and timber floors
> * 5:1 – Lintels supporting concrete floors
> * 19:1 – Lintels for eaves applications
>
>
> – [stressline.net](http://www.stressline.net/lintel-load-span-tables-a-beginners-guide/)
>
>
>
I can't make heads or tails of that (I think you'd need to convert the weight to either kNm or kN/m anyway, to make use of those charts). I'd say somewhere over [**5:1**, which is NASA's ratio](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140011147.pdf). But I believe the construction industry rather's a factor of seven, especially for lifting equipment.
---
*For story-reasons I need to know how shallow I can make it.*
I dunno; do the math. **The question is, what safety factor can you get away with.** Again, I dunno. A SF of 1 wouldn't, if you put *anything* on it.
Do more than 1 and less than 20; it's a cave not a cove (supported at each end; not an eave).
[Answer]
How about forgetting architecture and putting your city on a [lava dome](https://en.wikipedia.org/wiki/Lava_dome)? You could pick a dome like [this one](http://volcano.oregonstate.edu/shape-and-size-lava-domes) in Andes, and excavate by magic (or just very advanced mining) below it to form your cave. It should hold, because you have hundreds of meters of volcanic rock above your cave.
There are huge cave chambers such as [Sarawak Chamber](https://en.wikipedia.org/wiki/Sarawak_Chamber) which is 600x435 meters. If the cave ceiling is arched, there is a good chance it could be bigger.
[Answer]
I'm not an architect, but I think it is not the thickness, thickness adds weight but at the same time adds stability.
Consider brick ceilings, I don't see why this cave is not possible.
] |
[Question]
[
If the British, under the command of John Whitelocke, had been able to capture Buenos Aires in July 1807 (after a much smaller British force was defeated the year before, following an initial victory in a private, unauthorized expedition), how would the British have proceeded with the River Plate region and elsewhere in southern South America?
I was thinking, until recently, that all or most of Argentina and Uruguay (as a single country) would have evolved to become like Canada or Australia in terms of being anglophone and highly developed. However, from what I understand, that is not quite realistic, given that the Buenos Aires inhabitants were much more interested in independence than in rule by either the Spanish or British Empires, and the British government was becoming more interested in economic than political influence in Latin America in general. Besides, Buenos Aires had a much larger population than Montevideo; the latter's population size was more comparable to that of Cape Town (captured by the British in 1795 and again in 1806) or that of Quebec City (captured by the British in 1759).
What I have come up with lately, therefore, are two main possibilities:
1) Buenos Aires and the rest of Argentina proper (excluding Patagonia) becomes an independent state under British suzerainty ca. 1810 (since the British are likely to have trouble dealing with Buenos Aires directly - due to insurgencies in the surrounding area, relatively big population size, not-so-strategic value, etc.), Uruguay remains a British colony (because Montevideo, its capital, is more strategic to British interests than Buenos Aires), and Patagonia evolves to be a British colony. The upshot is that Argentina is an independent country while Uruguay and Patagonia are British colonies, then dominions, and finally highly developed independent countries under the British Commonwealth.
2) Both Buenos Aires/Argentina and Uruguay become independent British client states (in the event that the British find Montevideo as well as Buenos Aires too much to deal with, owing to insurgencies around Montevideo also), and only Patagonia becomes a British colony (then dominion and finally a highly developed British Commonwealth country).
Which of these two possibilities sounds better or more realistic?
[Answer]
The only reason the British were in South America is because they lost the American colonies. I don't think the British were ever really serious about taking big chunks of South America. The British had huge, valuable holdings and trade routes in the East, but not so much in the West.
So they would have if they could have, but the fact that they lost the Buenos Aires battle and basically left for good indicates that it wasn't very interesting for them, and it wasn't worth the effort. After that, everything was done by proxy.
If they had won the battle, it's likely that Buenos Aires would have been an important port, but only for maybe another 50 years or so. The end of the era of sailing ships made a lot of ports around the world a lot less important. And once you build the Panama Canal, there isn't any compelling reason to be down in the South Atlantic.
So Argentina doesn't get dominion status. It's not that important now, and it wasn't that important then. Compare it to Africa, where there were plenty of British colonies, but only one was a dominion.
[Answer]
I am not sure its right to assume that the south american would have fought for independence so quickly (although at some point would arguably have been inevitable). One key differentiation between the Spanish colonial rule and the British system was land ownership. The ability of the people to share in the wealth generation could have placated the populous enough to make it a major hub.
I think they would have expanded into Chile to make the colony cross-continental. In terms of trade, Chile/Argentina/South Africa/Australia would have almost guaranteed Britain trade and naval dominance of the southern ocean and the south pacific.
[Answer]
Let's not forget that prior to WWII and the presidency of Juan Peron, Argentina was in the the top ten wealthiest countries in the world. They still have huge resources there. They loaned money to to Great Britain. Great Britain not only had citizens living and doing business throughout the country but was instrumental in setting up railways, industry, and communities. There are still English and Welsh speakers there and an English language newspaper. It was Juan and Eva Peron who kicked out the British and removed Argentina from being competitive on the world stage. What Singapore is doing, they did exactly the opposite.
I do often think of the Welsh communities in the Patagonia who had their start in the 1890s tried to set up a little Wales outside of Wales. What would it have been like for them had they faced a favorable harvest and a little more luck?
[Answer]
Also very worth a gander:
<https://en.wikipedia.org/wiki/British_investment_in_Argentina>
"The question of informal empire and British hegemony in Argentina through investment
Towards the 1870s, it was clear that the British were extremely influential in the economics of Argentina. This set up a unique power dynamic between the two sovereign states of Great Britain and Argentina. Some scholars have even argued that Argentina was a product of British imperialism. A. G. Hopkins explains that for imperialism to occur, the sovereignty of one state is being diminished by another state with more structural power.[5] Susan Strange, an English political scientist, identified four main forms of structural power in her study States and Markets. One of these is "control over credit."[5] For a developing nation it is clear that a free line of credit is essential to nation-building. Capital is needed to build industries, and the Argentinians lost their line of credit when they declared independence from Bourbon Spain. Argentina as well as most of Latin America lacked the domestic capital to rebuild after the destruction of infrastructure during the revolutions.[6] Therefore, the City of London stepped in and funded the capital where Argentina could not.[5] In return for this foreign capital, the Argentinians were motivated to ensure political stability and keep the interests of the investors in mind.[5]"
] |
[Question]
[
**Background**
Several hundred years from now, humans have successfully terraformed the Moon. It has become a fad for the rich and powerful to have exotic residences built in exotic locations. The richest person in the Solar System decides to have his built on the newly terraformed moon. You are the architect. What does his home look like?
**Some constraints & assumptions:**
* We realize the Moon will eventually lose its atmosphere. Either they
have a method of replenishing the Moons volatiles or the humans are
shortsighted enough to not care - so do not worry about doing a reality
check on this.
* Atmospheric pressure is standard Earth atmospheric pressure at sea
level.
* The hydrosphere is at the reference "Datum".
* Colonization of the Moon is just starting so there's no restrictions
on which location you pick
**Other stuff** (some neat factoids that might be useful in your design).
* To create Earth atmospheric pressure on the Moon requires a great
deal more mass of air (6x more) - meaning radiation levels on the
Moon are much lower than on Earth
* Under these conditions a fit person can, with their arms, generate
1.3 - 1.5x the amount of force required to fly.
* Under these conditions a fit person should be able to run fast enough
to cross a body of water without falling in.
* A person should be able to survive falls 6x higher than the ones they
could survive on Earth.
* Running would be awkward. The decreased gravity gives the runner much less
traction (friction).
* It'd take a while to relearn how to catch falling objects.
* The Moon would still experience Solar Tides with a high tide
occurring every 15 days and I'd expect it to be about 3x as high as
terrestrial tides.
* Earthlight would be about 40x brighter than Moonlight is.
**Scoring:**
* Based upon utilization of the environment for the "wow" factor.
* The owner wants to show off his new house, so it needs to be
accessible to his friends.
* This location needs to be reachable for resupply too.
* Use of architectural features (probably but not necessarily to tie
into location) to wow his guests
* Use of the environment differences of the Lunar Colony from Earth to
wow his guests.
**Bonus:**
* Any unique situation experience which is especially pleasing or
pleasurable that can't be done on Earth (e.g. how would it feel to
float on an air hockey table as a bed?)
[Answer]
**Swimming Pools and Perches**
The house would essentially be designed like a giant bird cage. Platforms that must be flown to and the best pool in the solar system.
The [relevant xkcd](https://what-if.xkcd.com/124/) wasn't mentioned yet, which is surprising. Many of the same facts listed in the question can be found there, except one of the more exciting ones, humans could swim fast enough to leap from a pool.
[](https://i.stack.imgur.com/yFKfG.png)
Additional features would be building on the equator for installation of a space elevator to ferry guests and supplies. As well as having a large telescope room for "live Google Earth" images.
[Answer]
I immediately pictured a golden foil dome, so something like a yurt. But the gold foil would have many uses, plus it's gold, which shouts "rich!". It'll shield from radiation and help fend off too much heat. You'd probably need something harder to cover the top dome in case of meteors or something. You'd also want an interior pod to act as a house so one could take off their space suit.
Doesn't have to be a yurt. Just something I pictured. Gold foil definitely, though.
Here's a little article about the foil: <http://www.geek.com/science/geek-answers-why-does-nasa-use-so-much-gold-foil-1568610/>
] |
[Question]
[
Most "realistic dragon" questions start with the premise, "given what we know about bones, muscles, and the square cube law, how close can we get to a fantasy dragon". This is a great question that has been answered numerous times before by many different authors and biologists and whatnot for fun.
This is not that question.
This question can be thought of as the inverse. "Given what has been said about the capability of fantasy dragons, and accounting for the square cube law, what does that say about what it must be made of?"
Non-realistic exotic materials such as unobtanium are perfectly acceptable for answers to this question. I just want to know what the properties of that unobtanium must be.
---
## Physical Requirements
Let's take a Red Dragon from Dungeons and Dragons (3rd Edition) as our prototypical example, simply because there's a lot of specific geometry and measurements given for them in the book "Draconomicon".
According to the book, a "Great Wyrm" Red Dragon has a wingspan of 150 ft (~46m) and a body length (nose to tail) of 120 ft (~37m) which is comprised of a main body that is 35 ft (~11m) long with a diameter of 15 ft (~5m). (If relevant, it also has a 35 ft (~11m) long neck (and head) and a 50 ft (~15m) long tail)
It weighs 1,280,000 lbs (~581,000 kgs), slightly more than a 747.
I don't know whether a dragon with wings this size would be capable of flight no matter the super strength given, but let's handwave that by adding an arbitrarily strong updraft from the ground (even absurdly strong), and just calculate the required material strength of the wings based on that.
The materials should be able to withstand an acceleration of at least 40 m/s, in flight. (It can move 800 ft in 6 seconds from a standstill start)
---
## The Question
Given these measurements and flight requirements, what can we derive about what the exotic materials of its bones, tendons, and skin must be made of? How strong must they be for it to support its own weight and then some?
(Out of scope of the question: How does it biologically form these materials? How does it breathe? How does it power itself? How do its nerves work? In scope: How strong must the **structural parts** of the dragon be... skin, tendons, bones, and such.)
[Answer]
First we need to find a baseline. Dragons in fantasy behaves as a much smaller creature. It can change pose on demand, it can jump or even leap great distance, many times it body length. It is much more agile than an elephant thst is much smaller. So as a first step I offer to find a creature that has a similar agility. In my opinion it is bigger than a mouse - mouse is more agile, can jump tens of its body sizes, that would look extreme for a dragon. And it is smaller than a dog - a dog still has some limits to pose changing, it can jump but after a speed up phase, not so much from a spot, like a dragon can. I would say a cat is close in agility to dragons - maximum body size that can change pose without preparation, can leap a few body sizes, still can control its body orientation in flight.
So, why is it that important what animal dragon is similar to? Because we can use it to calculate everything, knowing body mass of a cat, 5kg, and a dragon, 500 tons. Mass difference is 100 000 times. In order to have similar biomechanics we can find a factor to scale all the mechanical properties.
Cubic root is 45 times - this shows linear size difference. Sanity check on creature size: cat is about 0.3m, dragon would be 14m. Close enough.
To solve the 'square-cube law', we need to take our biomechanical properties and multiply them by the third power of size to account for volume change, and then divide by second power to account for cross section of bones and muscles. Result is the same factor, first power, 45.
Bone strength is about 100 MPa. after scaling it properties up we would get 4500 MPa. We dont have practical materials in this range. Carbon fiber might suffice, but mandatory matrix for it will reduce it by a lot. Some single crystal materials might come close to this value. Or use some futuristic material like graphene in plastic matrix, will be about right. Barely possible, but within known physics.
Skin strength is about 20 MPa. Scaled up it would be 900 MPa. Which is achievable with kevlar in a matrix, except that kevlar doesnt stand water. Good but nothing exceptional here.
Muscles can create 0.4 Mpa of pressure. Scaled up it would be 18 Mpa, or 180 atm if hydraulics is used, which is similar to what we use in high end devices. Gears arent so good because pressure doesnt allow much force advantage. Electric motors directly can create only about the same 0.4 MPa and are not good as is. So hydraulics it is.
That was the fun part. Now lets talk problems. Cat's metabolic rate is 2 w/kg or so. Or about 10w for the whole cat. Dragon would have metabolic rate higher even per kg - becase its muscles are so much stronger. So I would expect dragon metabolic rate to be about 90 w/kg. It is extreme, but colibri is not that far off. But for the whole dragon that would mean 45 MW. Or about 20 tanks. Or 250 tons of meat to eat per day. That is a true unobtanium - to imagine a world where this creature can feed.
<https://www.nytimes.com/2021/04/15/science/tyrannosaurus-rex-population.html>
Assuming your dragon would be as effective as Trex, only a hundred can live on Earth at once. After this point the sheer hunger of these creatures will disturb the ecosystems balance too much to be stable.
And now the ugly part. Thermodynamics. To cool down and keep its temperature under 40\*C assuming outside temperature is 20 C, dragon would need about 2000 m3 of air per second to cool down. Thats not good. If internal temperature is increased to 1000 C, making it non-orgsnic for sure, air requirement drops to 64 m3 per second. Or assuming a large mouth of 1 m2 exchaust speed of 64 m/s. Similar to a sneeze. With such a metabolic rate dragon can resist heat exchange only a few hours. Then it must either breath heat out, or fly to cool down in the wind. Or reduce metabolic rate with a sleep or hibernation. Breathing requirement as oxidizer for fuel is about 15 m3/s. Or assuming a large mouth of 1m2 similar to a strong blowing when people do it.
In short it has to be a machine. Or magic. No biological system can allow such a heat exchange rate, unless it is in water probably. But not in air. No unobtanium can change the thermodynamics.
P.S. one possible option is 1600 tons of water per day to evaporate. Or it has to drink many times per day. Then air exchange need is reduced to about 200 m/s for a big 1 m2 mouth. Somewhat possible. Hibernating or flying most of the time could bring this requirement down by ten times, and then it is back to having a chance of being biological. No fur, no feathers, scaly skin could increace heat exchange area and turbulence, to cool better while in flight.
P.S.2 cooling is at best 1 MW, even with birds top speed. To use a flight to cool down the dragon will have to have 'meat fur'. Some sort of tissue that exposes blood vessels to the air and has a surface area that is many tens of times larger than dragons skin area. Bird feathers actually have blood vessel in their stem. Using this structure but without the fluffy part might do the trick - so the dragon will look like a hedgehog. But the spikes will be much smaller in comparison, so overall impresssion will make it look more like ordinary fur. And only when are close you could be able to see the spikes. Birds' feather stem is soft, not as dangerous as hedgehog's spike.
] |
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