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[Question]
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Imagine two races, both of human-level intelligence:
**Hawklings** are raptor-like (as in falcons, hawks, eagles, etc) flying humanoids who have six limbs: legs, arms, and wings. They live on high cliffs situated between open plains and the ocean. They hunt by soaring high in the air across hundreds of miles, "hovering", and swooping down at high speeds to snatch up their prey. They have [raptor-like tails/tail feathers](https://i.pinimg.com/originals/af/9b/e3/af9be3aec525d492547c6c3dfb73cb21.jpg) to aid in maneuverability. Flight is their primary form of locomotion; they can walk but prefer to fly over all but short distances. They can use their wings to glide starting at a few days old, and can fly within a few weeks.
**Groundbirds** are peafowl-like winged humanoids also with six limbs: legs, arms, and wings. They live primarily in dense forest or urban environments. They hunt by sneaking up on their prey from the ground, and pouncing. They have tails with [bones along the length and relatively few feathers](https://www.thoughtco.com/thmb/HiLOWvydJPouKrTerrj1dcnwXVo=/1280x583/filters:no_upscale():max_bytes(150000):strip_icc()/alvarezsaurusWC2-58b9b7113df78c353c2d3c95.jpg), which are used for balance and posturing. Walking is their primary form of locomotion; as adults they can fly several miles at a time, but mostly only use their wings to aid with jumping up/down, and for mating displays. They don't start using their wings in any real capacity until they're several years old.
**If a Hawkling raised a Groundbird child, what kinds of aerial maneuvers would the Groundbird ultimately be capable of?**
Humans are generally quite good at using intelligence to make up for relatively low physical prowess compared to the rest of the animal kingdom - we train, we explore unconventional techniques, we create tools/aids to give us capabilities we otherwise lack. So in other words, **given that both of these races have human-level intelligence, how much could a Hawkling-raised Groundbird adapt their capabilities beyond species norm?**
[Answer]
# No.
Just that, a solid nope. Normally I'd ask for some more information, but not only you said to just assume they can fly, you said it yourself that groundbirds are only capable of flying for relatively short distances and have a lifestyle that relies very little on flight. Much like ducklings raised by chickens alongside chicks don't suddenly become afraid of water, your groundbirds won't become magically capable of doing everything a hawkling can just because they were raised by one. Wings present in soaring predators like eagles and hawks are usually long, large, powerful and adapted to enable them to use wind currents to keep themselves in the air with minimal energy. A creature with small, broad wings, no matter how much encouragement it gets, can't get the same results without the same wings. It's like wanting a kori bustard, heaviest flying bird in the world, to take off with the same ease of a harpy eagle and make tight turns like a bat. It ain't happening unless we add in things like magic or anomalies that break the normal laws of the universe as we know it.
If you're having trouble with their anatomy, I recommend taking a look at larger raptors and juvenile T-Rexes, as they had longer tails, a ground-centered lifestyle and were adapted to function as nimble predators. Birds that rely very little on flight, such as roadrunners, might also be worth a look.
**Edit:** while your groundbirds might have human-level intelligence, that doesn't change much here. Humans have used their intellect and the knowledge we've accumulated over the years to build things that go beyond what common biology is capable of. The largest plane far outweights and oitsizes the largest flying animals to ever live. However, one thing remains the same: our technology has only gone so far in increasing our own limits. We might be able to live longer and know more efficient ways to train our body for certain purposes, but despite all of our knowledge and intellect, we'll still get absolutely bodied in a fight against an angry chimpanzee, and a human raised by a chimpanzee could never hope to get close to it in terms of climbing ability, sheer strength or speed.
In other words, unless they have some crazy advanced science in the fields of bioengineering, your groundbirds' intellect can only do so much to expand their natural capabilities. Meaning that, even when accounting for their intelligence, they'll still only be able to fly for relatively short distances, with little to no hope of soaring high.
What you could see is a groundbird raising a hawkling and teaching it how to move around on the ground and how to hunt properly. They won't be as good as a groundbird due to the fact that such teachings are specific to the groundbird based on their own anatomy, but the hawkling will have the knowledge, being able to try out ways to make use of it based on their own physical abilities and limits, because in here we're not talking about a physical ability that's clearly exclusive to the members of a certain species, but rather about knowledge that can be made useful by any species with enough intelligence to process it.
Basically, can intelligence alone without the use of genetic modification allow your groundbird to overcome natural barriers and soar through the skies along with their hawkling parent? No, just like no human today can even hope to swim with the same skill, speed or agility of a sea-lion or seal even with the best diving skills in the world and while using the greatest scuba gear in the market. Can they potentially learn something useful from what the hawklings know and **adapt said knowledge** so they can use it based on their own physical limitations? Pretty likely.
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*The Transgalactic Guide to Solar System M-17* by Jeff Rovin features, among others, the planet Morana, which is described as having oceans of "mud". Obviously, this cannot be normal mud such as we would find on Earth, for a few reasons:
1. It never settles out, and is described as "viscous", yet has a large enough fluid component to have global currents.
2. It is denser than water, but not denser than humans (or at least, not denser than humans in spacesuits), who will still sink in it despite feeling buoyant.
3. While visibility is low, it is apparently *not* zero--you can at least see through it far enough to make a submersible tour of the ruins of a sunken city worthwhile.
Is there any substance that would fit this (extremely vague) bill, which could potentially be available in ocean-forming quantities on an alien world?
[Answer]
[Slush](https://en.wikipedia.org/wiki/Slush) a mixture of solid and liquid of the same substance - behaves mostly as a non-newtonian fluid. Pick your liquids, you can even get water if you have forces that churn the mixture and prevent it from settling with ice on top and water at the bottom. Other liquids will have less of a density segregation, so you may get that in volume without churning - e.g. [Titan-style cryovolcanism](https://en.wikipedia.org/wiki/Titan_(moon)#Cryovolcanism_and_mountains) maintaining a suspension of heavier frozen hydrocarbons in liquid methane.
[Algal blooms](https://en.wikipedia.org/wiki/Algal_bloom) - will modify the viscosity of the water even on Earth by their sheer numbers - bonus point if they excrete [mucilage](https://en.wikipedia.org/wiki/Mucilage) or decay into one when they die. If you have a planet with many active volcanic vents and a biology tuned accordingly, you don't even need light to explain why the life continues in spite of the water become murky and in spite of a low level penetration of light (as an energy source for life to maintain itself and prosper against increasing entropy).
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The creatures on this world tend to favour arsenic as a replacement for phosphorous in their biology. There's an overabundance of it in the ground soil, and very little phosphorus.
The equivalent of mushrooms on this world pack their spores with arsenic as an essential chemical nutrient for their spawns survival.
[](https://i.stack.imgur.com/JSRiF.gif)
Is it possible that the resultant arsenic spore cloud would be dense enough to cause arsenic poisoning to anyone who breaths it in, over an appreciable amount of time, say a couple of hours? Assume that unlike the above gif, the spores become well mixed in the air (this may or may not impact how much arsenic they can contain), and the cloud rises to at least a few metres. More like the mist [seen here](https://upload.wikimedia.org/wikipedia/commons/9/9d/%D0%97%D0%B0_%D1%81%D0%B5%D0%BB%D0%BE%D0%BC_2.jpg)
Mushroom spores are, from some googling, about 40 micrograms in weight, and the LD50 of 13 mg/kg. Some mushroom spores [contain](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3546300/) phosphorous at levels of 10-20 g/kg, so the arsenic in a single spore was a 1-to-1 replacement, each spore would contain 0.8 micrograms.
At those levels you'd need 16,250 spores **per KG** of person to get an LD50. A human of 80kg would need 1.3 million spores, and "[a single basidiomycete mushroom is capable of releasing over 1 billion spores per day](https://www.pnas.org/content/113/11/2833)". That means in an hour something like 41 million spores per hour if it was released evenly throughout the day. It feels like this is more than enough spores.
However I don't know if my substitution of arsenic for phosphorous makes much sense, nor how dense the cloud of spores (spores per volume of air) would be?
Is this arsenic spore cloud something that could reasonable be lethal?
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## Please note: this question is tagged [reality-check](/questions/tagged/reality-check "show questions tagged 'reality-check'")
This tag should clue in any potential answerers based on it's tag wiki: "*Asks if a given concept is realistic in a given context. Answers should **say yes or no**, with **supporting info**.* " (emphasis mine). As such I am not soliciting discussion or suggestions on ways to improve this concept. The context above should be taken as an inviolable fact, and not something to be iterated on as part of this question.
[Answer]
**Yes**
Firstly, as far as I can tell, the substitution of makes sense. Although [it is unlikely that all the phosphorus would be replaced by arsenic](https://cen.acs.org/articles/90/web/2012/01/Arsenic-Based-Life-Aftermath.html) and your fungus will still much prefer phosphorus to arsenic, given that (it seems like) the idea of arsenic based life on Earth was seriously considered in the scientific community, it is definitely plausible. The only problem with your substitution that I can find is that because arsenic has a higher atomic weight than phosphorus, there would actually be about 2 micrograms per spore, so only around 7,000 spores per kilogram are required to reach the LD50.
Under ideal conditions, say 0.1m/s wind (I have to assume some wind or I cannot find a mechanism for the spores to get off the ground), if your patch is roughly a square with side length 2 meters (as in the gif), the spores will spend around 10 seconds in the patch. If that patch has 1000 mushrooms (this seems reasonable to me given the density of mushrooms in the gif) and each mushroom produces a billion spores a day, at any given instant, there will be around 10 million spores the patch.
If the updrafts are perfect (I am still assuming ideal conditions), the spores might be vertically spread out uniformly over the 2m or so of our theoretical person's height. If the person breaths in [7ml of air per kilogram per breath](https://en.wikipedia.org/wiki/Tidal_volume), they would need to inhale 700 times before they get the LD50. This would take around 45 minutes, but given a larger patch (that takes longer for the person to cross and has a higher density of spores), the arsenic could make it impassable. Given a 1m/s walking speed, and no holding of breath while walking on the patch, the patch would need to be 70 meters wide to give the LD50 to someone walking through it. Of course, the person would encounter a bit of arsenic while approaching the patch, so this width could be even smaller with a favorable wind direction. Also, even if it is not necessarily fatal, breathing while in a smaller patch [could cause a lot of nasty symptoms that could last for months.](https://www.healthline.com/health/arsenic-poisoning#symptoms)
[Answer]
**It would be a rough world for earth humans, spores or no.**
Concentrated arsenic spores would be very bad for humans. edit: Could they be lethal for earth humans: **YES.** Windblown dust from arsenic-laden soil would also be bad for humans over a longer period. The whole world would be poisonous for earth humans. Just inhabiting this world will pretty much guarantee arsenic poisoning eventually.
But probably not for the natives. edit: Could arsenic spores be lethal to creatures adapted to this high arsenic world: **PROBABLY NO**. If the high arsenic soil is how this world is everywhere, life native to this world would probably be adapted to high arsenic levels (even if not to the degree that these fungi are) and so arsenic spores would not be as hazardous as they would be to creatures from our world.
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This might be a good world for earth humans with syphilis. Maybe there could be a spa where syphilitic folks come for a time to soak in warm springs, huff some arsenic spores, participate in drum circles, write inspirational poetry. That sounds good.
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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 have a character that can create compressed air spheres. If you were to create just a normal sphere of compressed air, it would expand in all directions equally at a speed and force that would depend on how compressed you made the air. While that certainly *can* be useful under the right circumstances, its far more useful to be able to focus the air burst in a specific direction. Here are the limitations:
* When it comes to creating air, this means he has the ability to create any molecular structure that's a gas at room temperature and it is created *at* room temperature - though note that the more unnatural the gas is, the harder it is for him to create. Oxygen is fine, sulfur hexalfuoride can only be created in limited amounts.
* The character uses a magic ability to create air within a six-inch sphere of his choosing. The sphere is created at chest level about a foot in front of him. He can choose where any air is added within the sphere - for instance, he can add extra oxygen to the left side and nitrogen to the right if he so chooses.
* He cannot destroy air or move it - his ability is restricted to creating it. He can't have one side of the sphere be a vacuum, for instance, or do anything about the normal atmospheric air that's already in the sphere.
Given these restrictions, I thought it might be possible to create something resembling a 'shaped wind charge' - when crafting the sphere, the character uses a highly-compressed glob of lighter air, surrounded by a not-as-compressed shell of heavier air which serves to dampen the expanding lighter air and focus a blast in one direction.
The three limitations cannot be violated, though if it can only be done with large amounts of rare gasses, it is what it is. Tools (i.e. a gun facsimile) are not allowed, the goal is to do this using created wind only. So, the question is: what's the optimal gasses to use for such a shaped wind charge, and how effective will that end up being?
There is a **hard-science** tag applied to the question because I want very specific gasses.
[Answer]
# There are 5 effects I think have been overlooked here.
First, the obvious uses; Anything a nitrogen canon can do, this can do better, as its maximum pressure seems to he unbounded in the question, and the sphere can easily be placed near or in things to strengthen the directional focus, (we cant use other gasses to build a cone cause they'd mix together). A small hole in the ground is all that's needed to get a launch. Nitrogen canons are used in special effects to flip cars or launch buses over bridges, I'm just going to answer this section by saying "Buy the Mythbusters box set and watch them launch stuff with a nitrogen canon", and move on to what I think is the more interesting use cases:
# The pressure wave can be a sonic weapon
Build the pressure up large enough, release it suddenly, and you've deafend everyone in the blast zone not wearing ear protection. Extremes could result in permanent hearing damage, unconsciousness, or death. Fill it with air, face it at your enemy, fire, their eardrums burst.
# Gases change temperature when expanding
Checkout the <https://en.m.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect>.
The gases are created at room temperature yes, but as soon as the shield is dropped, that's going to change.
Hydrogen heats up when expanded from high pressure at room temperature, oxygen and nitrogen cools down when expanded from high pressure at room temperature. This gives your character the ability to heat or cool anything. Side stepping your rules about temperature.
Hydrogen auto ignites at about 550 degrees C, so I believe (open to correction here) enough hydrogen crammed into that sphere at room temperature would expand and heat further and further until it reaches auto ignition, and turns into a massive fireball when the shield is dropped.
# Perfect stoichiometry is possible.
You can create gas mixes, so 2 parts hydrogen, 1 part oxygen, perfectly mixed, and packed to crazy levels of pressure, is an <https://en.m.wikipedia.org/wiki/Oxyhydrogen> bomb. This auto ignites at about 550 degrees, and self heats when the shield is dropped same as normal hydrogen.
Burns at 2800 degrees C.
You could also combine this with a tiny forward facing hole in a container to use as a flamethrower / blow torch.
# You can mess with the weather.
The ability to create a lot of air at 25 degrees (room temperature) can create or destroy weather features. At the very least warm moist air at sea level suddenly getting pushed upwards by an expanding sphere of air? Instant vertical cloud with moisture travelling upwards through freezing conditions. That's a thunderstorm.
I reckon you could make a hurricane with a few well placed pressure fronts.
# And why not crank the pressure all the way up?
Theres no limit on the pressure apparently - just the more common the gas, the more you can create.
Can we get enough nitrogen or oxygen packed into a six inch sphere to create a black hole?
At first I thought "enough to create liquid - too much", but rereading the question I'm getting the impression this forces the substance to exist as gas at room temperature regardless of density.
[Answer]
**It's not possible.**
At least, not with the restrictions provided. With only the ability to create compressed sources of gases, we have lost the ability of most of science to help us model the effects fully. Any containment mechanism would have allowed this to work as a spontaneously created high pressure zone with containment is just like any other air compressor which we can probably find studies about the decompression.
Additionally, since gases try to fill the container they are in and follow [gas laws](https://www.westfield.ma.edu/PersonalPages/cmasi/gen_chem1/Gases/KMT/kmt.htm#:%7E:text=The%20size%20of%20a%20gas,gases%20can%20be%20easily%20compressed.&text=Gases%20expand%20to%20completely%20fill,were%20attracted%20to%20each%20other.). The important one here is "momentum and energy is transfered not lost during collisions". Heavier gasses will absorb more energy to move and will be affected less when imparting energy but, the expansion will still occur. "Gases expand spontaneously to fill any container" means that without a container to block expansion or absorb directional energy, We can't directionally fire gases.
However, if instead of just creation of gases at a set point, we can add directional momentum to it. This means that overall, the gases will tend to expand in the direction of the momentum due to the transferred energy being kept.
[Answer]
As is pointed out in the comments, the gases would mix. This answer is assuming that all the gases are placed instantaneously upon the release. You wouldn't be able to funnel the air fully, mostly because it wouldn't be possible to fully shape the air inside, leading to an area of fastest and slower air emerging. As far as raw elements go,A quick google search states that Tungsten Hexafluoride, while being a quite complex chemical, is one of the most dense gases currently known. It would work best as your "Shield", but correct me if I'm wrong. I don't major in this subject. Common sense states that you want an incredibly light gas, such as hydrogen or helium, to function as the payload of the wind charge.
Another thing I've found is that it would be possible to make a gaseous "bullet" using Xenon, Fluorine, and hydrogen. You would make a dense-ish outer shell of Xenon, Radon, or some other inert gas, have a Hydrogen secondary shell, a fluorine core, and a dense pocket of nonreactive (or highly reactive, I don't really know as this is just a crazy theory) gas to function as the "Bullet" of the weapon.
Please, don't hesitate to correct me on any of this. I don't have that much experience, and thus shouldn't be trusted as a major authority on the subject of wind charges.
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[Question]
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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.
**This question already has answers here**:
[How to explain something like a universal translator](/questions/29727/how-to-explain-something-like-a-universal-translator)
(6 answers)
Closed 3 years ago.
In *Hitch-Hiker's Guide to the Galaxy* I know you put the Babel Fish in your ear and it telepathically translates any language, and the one from *Star Trek* could translate languages that the Federation had encountered but had limitations.
Basically, what would it take to make a non-organic device that can translate any foreign language it encountered? What would it need to be able to do? Like if an alien from another galaxy arrived in Milky Way space?
[Answer]
The "Babel fish", as described by Douglas Adams, is outside of realm of modern science.
Translating from a previously unknown language, without any references, is an unsolvable task. The original Babel fish worked off "brain waves", not sound waves, which provided a logically conceivable way of translating the meaning of the speech. There was a premise that brain waves are uniform enough for all sentient species that a single organism (or device) is capable of detecting and deciphering them all. So, in effect, underlying brain activity should have been much more common than the language.
If we want to develop an universal translator like that, first we need to prove that brain activity can be read from a distance and translated into information stream that adequately represent individual's speech.
However, if we don't want to develop a telepathic translator, but would be satisfied with acoustic one, the task can be solved with present science, to an extent. The resulting translator, even if powered by a "perfect" AI, would have the following limitations:
1. The device must clearly hear (and see, if necessary) every articulation of the speaker;
2. If the language is known, a "best guess" translation is produced (but even the best guess can be wrong). Upon better understanding of specific context and dialect, device can improve the translation.
3. If the language is unknown, a learning period should follow before any accurate translation can be made.
4. Depending on complexity of the language and willingness of the speaker (or speakers) to "teach" the device, this learning period can take a while.
[Answer]
Excellent question, and one that's challenging to linguists and anthropologists. Adding extraterrestrials makes it even more complicated.
On Earth, human languages spread, evolve, and recombine in ways that can be tracked. Languages evolve much the way organisms do, mutating and expending in complexity or simplifying and streamlining. Languages are modified by the values of the culture speaking them and the major historical events and eras preceding them. Many modern languages can be traced back to common ancestors. Most European languages derive from some combination of Latin, Greek, or various Germanic languages. If you study Latin, it's a lot easier to learn Spanish or Italian, for example. So the big question is if you traced all modern languages back would you find a single common ancestor to all human languages? If you did, could you build a linguistic model from it, extended by the languages that evolved from it, and use this to understand every other human language since?
Assume that you could. It's not unreasonable to assume, since all human languages were created by human minds inside human brains with largely identical human emotions, logic, and values.
But, would this extend also to extraterrestrials? If it did, there's two ways it would:
**We've communicated before.** In the *Star Trek* universe, human languages share roots with Romulan because they'd visited Earth and taught the humans. Many sci-fi universes follow this Ancient Aliens concept where the basis of human culture (including language) was taught to us by extraterrestrials. The *Alien* and *Predator* movies, for example, or *Stargate*. Flipping it around, several franchises have suggested all languages derived from a single ancient civilization (usually Atlantis) and at the height of that civilization humans were going into space and communicating with extraterrestrials on other planets. In such a scenario, it's not unlikely that *we'd* plant the seeds for an alien species' language to be derived from ours.
**Language is connected to intelligence.** Human languages are the product of human minds, but would alien minds be that different? Perhaps there's a linguistic root that most intelligences converge on, much like how many of Earth's animals have converged on similar body shapes. See [Carcinisation](https://en.wikipedia.org/wiki/Carcinisation) for a really weird example of this. This sounds really anthropocentric, just assuming humans are the ideal, but there's an argument to be made for it. It has been observed that dolphins form syntax in their communication, not just making noise but actually forming logical constructs from sequences in their clicks. [More information from the Dolphin Communication Project](https://www.dolphincommunicationproject.org/index.php/2014-10-21-00-13-26/dolphin-language). Granted, dolphins are still of Earth, are even mammals, and would likely have brains more similar to humans than some extraterrestrial species.
[Answer]
**a Universal translator at first glance is impossible**
Lets say I send you a binary string "00010101" translating that to base 10 is simple. 21. But then I tell you that it is in big endian notation, and the actual answer is 168. But I actually mis-translated this because it was supposed to be in unary, so the value is 3, ect, ect.
*If you don't know the standards of a language there is no way to intuit from meaning from any sequence without context*
**You can still have translators**
Lets say you have 100 years of radio chatter from a civilization that you collected while in hyperspace to a civilization. first you can have the computer identify patterns and attempt to locate a language teaching broadcast. This will start with a low set of words and increase in succession. you can then guess words and cross reference with the other radio audio you have.
A computer can also easily identify patterns and determine the grammar and syntax of systems, the computer can then create graphs of related words and based on known statistical patterns to guess the meanings of words. Any words that you have and they don't can be replaced with approximations based on known language.
If no radio transmissions exist, you can just monitor conversations secretly and compile data like that. doing this in secret is very important since if you are making first contact then "what the fuck is that thing in the sky" will have the same statistical frequency and placement in sentences and complex greetings, which might throw off you algorithm a bit.
[Answer]
**Cochlear implants and AI**
Normal hearing is a thing of the past. cochlear implants can catch the sound over many frequencies and be stronger than the normal ears. This can prevent hearing loss from loud noises and if they do break they can be easily replaced. cochlear implants listen to sound and then translate it to electrical stimuli which is sent down the nerves.
All sound is monitored. If a language us detected the person doesn't know, it'll translate it for him before it's added to the sound stream. If an unknown language is discovered, it'll use an AI database with all known languages to infer what the aliens are saying. Inflection and such are also in there. It'll start difficult, but an AI with such a large database will be able to crack alien spoken language. There might still be some problems with vast cultural differences, but nothing is perfect. Possibly camera's can be added to see visual queues to the decoding of the language.
[Answer]
The answer should be Universal Meaning.
Every language (even those that use pictures, splashes or thinking) have to express something meaningful - like I am hungry, Cold in here, or even much more complex thoughts.
So every language should be translated into UM and after that into new language.
Phycicaly, you will have to measure the sounds, body language with camera, and everything possible (body temp,..) that will make you closer to real meaning.
[Answer]
Magic
While it is possible to generate a translator for **known** languages, given a large enough database, grammar rules, some form of AI etc. there are two impossible hurdles to take for a **universal** translator that can also translate **unknown** languages.
## reference
Given an arbitrary word from an unknown language, there is absolutely no way you can figure out what it means. Imagine the alien looks at you and says "Grublxkn". That could mean virtually anything and you have nothing to figure out which of the many options are true. It could be a greeting, a threat, a question, its name, its term for your species, or it could be completely unrelated to you.
In human languages, we could find a near relative and make an educated guess from there. If the word sounded spanish or the speaker looks spanish, and Latin is in my database, I would have at least **some** information to draw on.
Also, when we learn languages, we learn them **with references**. Parents don't simply repeat a word for a child until it understands. They will point at various dogs and say "dog", giving the child a reference to associate the word to.
With unknown languages and alien races, no such luck.
## thought
Language and thought are related. To the point where some (e.g. [Sapir-Whorf](https://en.wikipedia.org/wiki/Linguistic_relativity)) say that you can't think what you can't say. An unknown alien species could have entirely different thought processes and thus entirely different language that does not follow any of our known rules of grammar or structure. The movie "Arrival" explored such a scenario, though in a very simplistic way (in the end, the aliens had words and sentences, anything else would've been too heavy for a movie audience I guess).
If someone **thinks** different from you, and his language has expressions that yours simply lacks, there is a translation problem. We see a bit of that even in human languages, especially in poetry. Sometimes you need two or three sentences to explain a single word (japanese is famous for that). Expand this to grammar - for example some languages allow you to express in a grammatical case whether what you are saying is first-hand knowledge or you only heard about it yourself. And that's **human to human** language translation. It takes experts extensive study to be able to halfway properly translate between those. No amount of tech or AI will let you make a translation from an unknown language with different rules based on a few words, phrases or sentences. There's just not enough information in that to understand the structure and meaning, much less to build a dictionary.
Even building a universal translator that over time **learns** a language the way children do would face this obstacle. What tells you that aliens learn their language the same way?
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*note: apparently, some readers miss the irony of answering a hard-science question with "magic". So to be utterly clear: What that word means is simply a shorthand expression for: No product of science or technology within the imaginable or even slightly hand-waverium, unobtanium based sphere will be able to produce such a device.*
[Answer]
A true universal translator requires omniscience, mostly because "language" is just a societal construct. Say two friends get together (say Jane and Alice) and invent a couple new words so they can communicate in secret without others knowing what they're saying: that's a language (albeit a very primitive one).
For the universal translator to properly translate what Jane and Alice are saying to each other, it would need to know everything that Jane and Alice know. Now, for humans, you could conceivably make this translator some sort of mind-reading device that scans nearby brains for information, but what happens when Jane and Alice start using their language outside of your presence? What if you simply hear an audio recording of them talking, and their brains are nowhere near?
This is why for a truly universal translator to work, **it would need to know everything about the entire history of the universe up until the present** to function properly.
The only "hard science" or "science based" method I can think of to make this work is if you buy into the [simulation hypothesis](https://en.wikipedia.org/wiki/Simulation_hypothesis) where you believe that our entire reality is a simulation. In such an environment, **advanced technology could conceivably interface directly with "God" aka. the system administrator and request knowledge to make the universal translator work.**
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[Question]
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Several questions on related subtopics of vision distance on a flat world have been asked before, but this one remains unaddressed. Specifically:
* The answer from Euclidean geometry would be infinite (no horizon). That's not what I'm looking at here.
* The answer from general relativity would be on the order of a light year (assuming constant 1g, bending light rays down). That's not what I'm looking at here.
* The answer assuming diffraction-limited seeing would depend on the angular size of the object you are looking at. But in practice the limit would be set by the atmosphere, not diffraction, so take a mountain range as the object to eliminate angular size as a consideration.
* Many locations on land have line of sight obstructed by nearby trees, buildings etc. So I'm taking the ocean as a starting point, to eliminate that limit.
* Smoggy city air would be unusually limiting. The Pacific Ocean is a good baseline; the air there isn't perfectly clear, but it's about as clear as air tends to get.
So: on a flat Earth, from a boat out in the Pacific, how far could you see the Andes? That nails down the limiting factor as absorption and scattering by air. (And someone asked how high above the water. Okay let's say ten meters above the water, high enough the waves won't obscure your vision, low enough to be effectively zero compared to the scale height of the atmosphere.)
Apparently there are known equations from which this can be calculated, but they are not particularly accessible to a nonspecialist. I'll start by throwing in some data points.
<https://www.flickr.com/photos/lattaj/6896706847> 'Atlanta Skyline From Brasstown Bald'. That's apparently 90 miles (145 km), and the Atlanta buildings are somewhat faded, contrast-reduced, but still clearly visible. The height of Brasstown Bald is 1458 m, not that high as mountains go. In particular, a horizon calculator says Atlanta is somewhat below the horizon from that height and distance, which explains why we only see the tall buildings. It's worth noting that the curvature of the Earth impairs visibility of even the tall buildings, by bringing the middle part of the line of sight to lower altitude, therefore denser air, which will absorb and scatter light more strongly than would be the case on a flat world.
<https://www.reddit.com/r/MapPorn/comments/5i333o/the_longest_ground_to_ground_line_of_sight_ever/> 'The longest ground to ground line of sight ever photographed is 381 km (237 miles), from Mont Canigou in the French Pyrenees to the French Alps, against the background of the rising sun'. Canigou is 2785 m. Horizon distance for that height is 188.5 km. Of course in this case the other end is at significant elevation also, but still the line of sight distance is not small compared to the horizon distance, so the curvature of the Earth is significantly impairing visibility by bringing the line of sight down into denser air. On the other hand, that same curvature aids visibility by silhouetting the target mountains against the rising sun, which massively boosts contrast.
From the discussion linked above, 'Actually, this record was beaten by the same person who did this sighting, and now stands at 443 km between the Pic de Finestrelles (In the Spanish-French border in the Pyrenees, near Mont Canigou) and the Pic Gaspard (Massif des Écrynes, French Alps).' Pic de Finestrelles 2826 m, Pic Gaspard 3880 m. Horizon distance from the latter altitude is 222.5 km. Again, there is elevation at both ends, but still, the horizon distance is not large compared to the line of sight distance.
For reference, the highest peak in the Andes is Aconcagua, 6962 m, somewhat less than twice the height of Pic Gaspard. It's clear that higher altitude aids visibility. Even on a flat world, with no horizon to worry about, raising the altitude of either end, aids visibility by moving the line of sight into less dense air.
Based on the above data, I would tentatively conclude that on a flat world, objects near sea level would vanish into haze at a few tens of km, but high mountains could be visible on the order of several hundred km away, with the caveat that this would be true only on a clear day, and you might have to wait many days for such excellent seeing conditions. If both ends were high mountains, it's conceivable that visibility might go into thousands of km, though at that sort of distance, the probability of no clouds anywhere in the line of sight becomes small, as does the angular size of even a large object, so that distance might not be practical.
Is there a way to nail this down more precisely? Are there any factors I'm not taking into account?
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You can go by your answer that estimates 100-120 kilometers because of air diffraction.
I was living in south france, Toulouse, for a long time, near the pyrenees. They were about 100 kilometers away; and they were about one and a half thumb above the horizon. But you could nearly never see them because of dust in the air and diffraction.
On a day when the pyrenees themselves were in the sun, and there were clouds on the way so no diffraction would hinder your sight, early in the year so they were still snow covered, they looked as if they were next to me. That happened about ten times per year maybe.
On a day when it didn't rain for weeks, I've seen just blue or even yellow sky. As if they were not there.
In northern germany there is the tower of Laboe. Northern germany is perfectly flat.
The tower has 70 meters height. Theoretically you have the perfect unobstructed view from there. If you want to see something, you have to be early in the day or on a cloudy day. As soon as the sun shines and gets some time to do it's work, the baltic and northern seas fill the air with a haze that just doesn't let you see very far.
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Cicadas are known to produce very loud sounds which [they make by rapidly buckling their tymbals](https://www.sciencemag.org/news/2013/06/secret-cicadas-chirp), some of which are [loud enough to exceed the threshhold that causes discomfort in humans (110 decibels)](http://www.bbc.com/earth/story/20160331-the-worlds-loudest-animal-might-surprise-you), though none are yet known to exceed the threshold where they might cause outright pain or hearing damage (130 db). [Larger cicadas have larger resonating organs and are said to be able to produce louder sounds](http://www.bbc.com/earth/story/20140929-the-loudest-insect-in-the-world).
Given this, **I am wondering how loud a cicada would be if it were scaled up to the size of a human being**, handwaving associated issues like a cicada of that size would not be able to function because of the effects of the square-cube law on its exoskeleton and respiratory system. I know that size of a resonating structure is inversely correlated to pitch (frequency), but I am unaware of any clear-cut relationship between "loudness" (decibels) and size. I am specifically interested in **whether this sound would be loud enough for the human-sized cicada to use as a sonic weapon**.
**EDIT:** As JBH pointed out in their answer, there is a world of difference between what constitutes an "effective" sonic weapon depending on what it is being used for. For the purposes of this question, I am talking about a sonic weapon in terms of how most modern sonic weapons are used, [an anti-personnel device used to incapacitate or cripple opponents](https://en.wikipedia.org/wiki/Sonic_weapon), rather than a device that uses extremely high-power vibrations to blow holes in buildings or something like that.
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**Unfortunately, no.**
Referencing the comments made by both @AlexP and @DWKraus and noting that one of the articles you cite states, "The detailed mechanism of the cicada's song is far from fully understood...." In other words, my answer is a best-guess.
A human-sized cicada would produce sound with a *substantially* lower frequency. Your largest cicada species (*megapomponia imperatoria*) is approximately 2.25 inches (5.5 cm) long with a wingspan of up to about 7.85 inches (20 cm). Since I don't have the ability to analyze with detail the tymbal (see image below, courtesy Vassar College), I can't be at all precise, but let's make some rough (OK, *really rough*) estimates.
[](https://i.stack.imgur.com/2jHmp.png)
[Average human height](https://www.healthline.com/health/average-height-for-men#how-to-measure) isn't all that simple to calculate — so I'm going to use 5' 7" (1.7 meters). That gives us a ratio of 7.85-to-67 or 1:8.54.
Now, a cicada's chirp is non-linear, but let's make another basic assumption. Cicada's [buckle the tymbal 300–400 times a second](https://www.sciencedaily.com/releases/2013/05/130530152846.htm). So, for convenience, we'll use a single average frequency of 350 Hz.
350/8.54 = 41 Hz.
*There's an assumption here that I'm making. I'm assuming the increased size of the cicada impacts just how fast the cicada can do things. Humans can't snap their fingers 350 times a second — and I don't believe that's an unreasonable example of the problem. If we could, we'd be creating the very effect you're looking for. But even if we could... it's the difference between tapping a snare drum 350 times a second vs. tapping a big bass drum 350 times a second. The result is a low frequency hum.*
*However, it is certainly worth pointing out that I've mixed apples with oranges. I've used the cicada's snapping frequency to cover for the fact that I can't find a reference for what frequency the single-snap "chirp" is at. This might be a massive (and most certainly is a massive) weakness in my answer — but I'm not convinced figuring out the specifics would change the conclusion.*
**Question #1: Can a human hear this?**
Yes, the range of human hearing is [20 to 20,000 Hz](https://en.wikipedia.org/wiki/Hearing_range). We'll ignore the fact that pretty much no two people are alike and that a bazillion things can vary those two numbers. But, for the most part, yup, the sound your human-sized cicada makes can be heard by the average human.
**Question #2: What's the volume?**
What a cicada is doing is little different than striking a drum with a stick. Increasing the size of the drum does not increase the volume. It's usually the opposite effect. Have you ever gone to see Blue Man Group and watched them use that [giant drum](https://lh3.googleusercontent.com/proxy/8jrt3ATACzs048tldJHYIlaQQ1lCDqq3Y_LXlwxWTjGti0fQG_bpqpN95Ta3q5ZZ9n4WLLd_95MEXWSeXD8yMT3_d5h5GbSuWaqv_BNPzCCMTFNbljc9Z3wJyB-yRFOmR1FX6YQmajEe9leIE_-DyeaTI3VMcNTc3rVdM3j87h8kdN8mxYcKGfbCdNeU5PiFBVwEvPzMsUybGccxbbw8)? There's a reason that dude's whacking away at that drum with a honking huge mallet ... just as there's a reason why subwoofers usually need their own, separate amplifier.
It takes a *LOT* more power to produce hearable volume at lower frequencies than at higher. This actually makes sense when you superimpose a low-frequency sine wave with a high-frequency sine wave. (Example below courtesy ScienceDirect.com.) Simplifying the way audio works enormously, you're being "hit" by the low frequency wave once during a time period equal to its wave length, but many times during the same period by a high frequency wave. It's like being hit once vs. being hit thousands of times during the same period of time. To feel that single hit with the same "perception" as those thousands of hits, you need to be hit harder.
[](https://i.stack.imgur.com/Qj8La.jpg)
**In other words, it's all about power...**
But once you get the power at low frequencies — you can feel it! Unfortunately, that's where we run into a problem. Unless you make the assumption that the cicada's ability to put *oomph* into buckling the tymbals increases *non-linearly* with size, you'll get the deeper sound, but not a louder sound. In fact, you'll get a quieter sound.
*That was certainly a debatable statement, and DWKraus points out that larger cicadas are louder in nature... but there's a lot of complexity involved here including the extent to which insect structure can be maintained as size increases. If scaling an ant, which can carry a much higher weight-per-body-weight than humans, to human size maintained that ability... then you'd think humans would have that ability... but we don't. I'm not a doctor and have never played one on TV, but I suspect that with dramatically increased size comes increased inefficiency, which is probably why elephants can't topple skyscrapers. That's my guess. But I could be wrong.*
**TL;DR**
Your human sized cicada would make a substantially lower frequency noise at, at best, the same volume (phons/sones as @AlexP points out) as their normal-sized cousins. The sound would therefore be no more uncomfortable than hearing a teenager drive down the street with subwoofers blaring in the trunk of their car.
On the basis of being used by an individual cicada — I can't see this working as a weapon.
Now, if a *whole swarm of human-sized cicadas started chiping....* [Angels and ministers of grace defend us!](https://www.youtube.com/watch?v=u0jQKFCE5J8) *(watch that video all the way to the end. The quote is from [Hamlet](https://www.opensourceshakespeare.org/views/plays/play_view.php?WorkID=hamlet&Act=1&Scene=4&Scope=scene))*
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Ok so my creature will look like this
[](https://i.stack.imgur.com/3hCo4.png)
* They're not big, about 2 feet tall.
* They're technically amphibians but have the scaly hide of a reptile.
* They live near the sea.
* Their life cycle is similar to that of any amphibians.
* They get their bioluminescent ability when they're a larva from fishes or any food source that contains bioluminescent material (eg. flashlight fish, firefly squid, etc.) and they collect this material in a special organ.
* They can produce a light bright enough to temporarily dazzle a creature and can do this during the day or night.
**I want my creature to have the ability detailed above and to be able to use it against attackers (of any size). How big does its light organ must be to produce that much light? and how many times can it do it?**
[Answer]
The sun puts out about 1000 Watts per square meter, or about 0.1 Watts per square centimeter.
The human eye has a blink reflex of about 1/4 of a second.
Maximum permitted exposure related to a light source equivalent to the sun, and when the pupils is constricted to about 2mm in diameters is a little under 2 Watts per square centimeter.
[](https://i.stack.imgur.com/3jyJ1.png)
So you probably want an organ to be able able to produce that much light intensity at some distance lets say about 10 ft or 3 meters, if the diameter of the spot was about 20cm, then pi r squared give the need to illuminate about 300 square centimeters or about 600 watts.
That might be a problem if the creature needed to produce 600 watts continuously. For reference a human at rest is about 100 Watts in just the thermal energy it radiates. A resting human probably needs about 1400 calories for its base metabolism. To compare: 600 joules per second\* 86400 seconds per day divided by 4184 Joules per calorie would mean the creature would need about 12,390 extra calories per day just for its light source. Thats about 30-40 ham sandwiches.
However, to dazzle, if it is pulsed light that needs to be only 1/4, maybe 1/2 a second, each light pulse would only need a fraction of a calorie.
The next problem is the efficiency of getting the light out of the creatures body. The sun's rays are parallel by the time they reach the earth, and that is important since that helps the dazzled creature eye focus the light onto the dazzled creatures retina. If the light is being produced in all directions inside the creatures body, then most of it is going to be absorbed in the emitting creature's body. That might be o.k. but it might need some kind of reflective coating around the organ, and that could be tough compared to a photoreceptor and even be able to take some heat build up per pulse. Since it is a fraction of a calorie, we could say the creature might use up a ham sandwiches worth of calories per pulse and still be o.k. if the creature didn't pulse too often.
Now to answer the question about the size of the organ needed.
The nice thing about bioluminescence is that is is about 96% efficient and little waste heat is produced.
1) If it is the bacteria themselves, I suppose you could try to have them coordinate to all flash at the same time. That could be stimulated by a chemical signal, or perhaps telepathic signal by the creature.
2) If the creature extracts the needed chemicals from the bacteria, it could have a more concentrated biochemical light source, but would need some mechanism of keeping the component chemicals separated. However this might have the advantage of being much more efficient per volume.
With approach 1 there are issues in having good ways to feed them, keep them alive, but also the energy density is probably a factor of 10 or perhaps 100 x less than mixing the component chemicals. If it is approach 2 the chemicals there probably needs to be some kind of storage, and specialized membranes to purify and keep the chemicals from reacting and tissues to mix the chemicals when needed.
From an Encyclopedia Britannica for luminescent materials
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> The energy required for excitation therefore ranges between 40 kilocalories (for red light), about 60 kilocalories (for yellow light), and about 80 kilocalories (for violet light) per mole of substance<
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Assuming a two types of molecules with a total atomic weight of 100, (100 grams each per mole) that would react and excite different molecule to be excited for another 50 to 100 grams that that would release the photons. That might be about 300 grams for the chemicals. The for the system perhaps as much again in for grams for the tissues, that would be about 500-600 grams which is about the size of a large human fist. You might make it a little bigger for optics, or the cavity, and make it longer to have a better telescope or something. This assumes the reacting molecules all react quickly, but there might actually be a longer glow after the chemicals were mixed.
There are probably some bad chemistry assumptions but for a ball park without getting into the details of the molecules and how they react etc. it might give a rough idea.
Since volume goes as the cube. if the chemical method was about 10x10x10 cm, and the energy density of the biocells was 100 times worse, you need a volume of about 46x46x46 cm.
[Answer]
I think you need a late twilight world where bright lights are rare. On such a world, those lifeforms which even use sight as one of their senses, would have large eyes with greater dilation ability than comparable creatures on brighter worlds.
Speaking of that dilation ability, if your world is very consistent in its' light levels, the muscles devoted to changing the aperture of the eye might not evolve great speed and agility. If the difference between noon and midnight was very small and flashes of intense light were very rare, then there would be little survival advantage in having fast eye muscles.
In this kind of environment, your creature's light emitting abilities would have to be novel and revolutionary (new on an evolutionary scale) or its prey would have started evolving faster eye muscles by now.
So finally, we have a platform upon which your question can be answered. In a dark world, the quantity of light needed to stun the eyes would be within the chemical potential of bio-luminescence. The creature's organ should have eyelid like shutters so that it can build up the brilliance inside with lids closed, then snap them open for a blinding flash. If the blink rate of those lids were synchronized to the dilation rate of their favorite prey, they could flash at exactly the right speed to keep their prey's eyes wrongly dilated for the current moment's light level. If their own eyelids were wired up to blink at the exact moment of each flash, they might be able to keep their own vision while disabling that of their prey.
So to finally answer the question, if a eyelid like shutter is employed to keep the continuous light hidden most of the time, then the organ only needs to be big enough to house and symbiotically maintain the necessary quantity of luminous bacteria. That can be relatively small as long as the organ has the strong blood supply necessary to keep the bacteria well fed.
There would probably be no limit to how often it could use the organ because inside the closed shutters, the bacteria are always glowing; but with the exposed location of the organ and the requirement for a heavy blood supply, the organ would probably also be the creature's Achilles heal. The natural reaction of any prey, which was lucky enough to not be immediately blinded, would be to attack the source of the light. If successful, such an attack would not only level the playing field, it would leave your creature with a heavily bleeding wound that might possibly be a fight-ending/life-ending injury.
*Afterthought : It isn't necessary that the entire world be late twilight. If the creature were subterranean or if it lived in a massive forest in which the tree canopies blocked all light from reaching the ground. Such a localized dark environment would either need to be enormous or isolated by un-passable lands on all sides to keep it's inhabitants isolated in the dark. In such conditions, the evolutionary forces which I described above could still apply, despite there being high-light-tolerant, fully sighted creatures elsewhere on the planet. Please note that your creature's dazzling display will not be as effective against those outsider creatures who evolved in brighter conditions and as a result have more experience and biological preparedness for sudden light level changes.*
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The real trick is aiming. As AlexP points out, at night a laser pointer can provide a tremendously powerful disruption. Of course, during the day, the sun is *really* hard to outshine. It will be hard to generate enough light to even show up during the day, much less be dazzling.
Use it to your advantage. Put a reflective membrane on the light source to point it in the direction of the predator. During the day, use the same reflective membrane to reflect the sun in their eyes. As an added bonus, you can apply some musculature to this to shape a lens of the right focal length to target their eyes directly.
When preparing for the last solar eclipse, I did the calculations for just how bright a mere 8" telescope makes the sun appear when it is focused on your eye, and how long it takes to not only dazzle but to cause permanent irreparable damage. The answer was not *freaking* long. Terrifyingly short, actually, as one gets ready to watch an eclipse through said 8" telescope!
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You can simply make it nocturnal and it becomes quite simple. At night, many creatures' pupils widen and enlarge, seeking out any light they can find. Flashing a bright light at these night predators will probably stun them almost as badly as staring at the sun for a brief time, leaving them incapacitated enough for your creature to get away before the creature comes back to its senses.
However, if you're looking for a distraction that will mesmerize predators and prey alike, I have two other great adaptations. Cuttlefish use chromatophores in their skin to stun any prey that look at them, making them unable to move. Meanwhile, the cuttlefish's cousin cephalopod uses ink to disorient predators. Instead of ink, you can use a heavy dark gas. Some octopus ink is toxic enough to leave a bad enough taste in a predator's mouth to lose its appetite.
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As we know, bi-directional faster than light (FTL) travel can cause paradoxical situations. One possible way to resolve this would be a multiverse theory: Whenever a paradox could arise, the universe splits into two (or maybe more) more or less internally consistent universes, and whenever a paradox actually *would* arise this split becomes observable.
Let's take the [Alice and Bob example](https://en.wikipedia.org/wiki/Tachyonic_antitelephone#Numerical_example_with_two-way_communication) from the wikipedia page on the tachyon antitelephone:
Alice and Bob are travelling at 0.8c away from each other from a common starting point. After 300 days subjective time, She eats bad shrimp and sends a message to that effect "I ate some bad shrimp" to Bob. The message travels to Bob at 2.4c. Bob receives the message at *his* subejctive time of 270 days (due to time dilation as seen from Alice's standpoint, math behind the link). He immediatly sends back a warning "Don't eat the shrimp" at 2.4c relative to *his* frame of reference which reaches her at 243 days "Alice-time". Provided Alice doesnt forget the warning in the following two months, she won't eat the shrimp, won't message Bob, won't receive a warning, will eat shrimp, will message Bob ...
(**Edit to add: The preceding paragraph summarizes a thought experiment that was first thought up by Einstein in 1910 and worked on by other physicists. If your answer boils down to "Bidirectional FTL travel cannot create paradoxes, Einstein was wrong on relativity" your answer is bad and you should feel bad**)
How could this play out in a Multiverse as sketched above? From Bob's perspective, he will receive a message from a futre that will never happen. Weird but not non-sensical. The same holds true for the Alice who receives the warning.
The possible paradox happens from the Alice-primes perspective: She sends a message to Bob but has not received the return message. When Bob and Alice communicate via non-FTL means she will learn he sent a warning that she did not receive (it simply vanished). The only way I see to resolve this is that *return* messages or trips that are quick (and close in time) enough to cause a paradox vanish from their senders perspective, and consequently from some receivers. While this requires a serious rethinking of causality (things happen for which the cause is outside *this* universe), within one timeline there are no causality violations.
*Most* times this will only happen when someone wants it to: Say ESA launches a space telescope at .99 c to observe the future history of the universe, or commanders on opposing sites of a space battle use relativistic spysats to adopt their battle plans by looking at one outcome (that is rendered impossible immediately).
The biggest downside from a storytelling perspective I see is this: Anyone capable of accelerating many tons of matter to relativistic speed and have it travel back with an FTL drive can duplicate matter: Instead of eating a shrimp Alice sends it to Bob, who sends it back. Now secondary Alice has two shrimp. Unless we limit FTL to information.
**My question is: Do the preceding paragraphs make sense or is there a serious flaw in my thinking?**
For storytelling purposes this works best with FTL devices where the travelling ship vanishes into a sort of warp bubble and cannot communicate with the rest of the universe until it pops back into sublight space. Maybe it could work with wormhole-like travel.
p.s. Let me explain the *spirit* of this question: FTL is impossible in two distinct ways. There's (IMO) no mechanism in sight that could feasibly allow any signal to travel FTL - that's one impossibility. The other is that unless relativity is grossly wrong (and we'd know by now?) FTL could lead to paradoxes as described above. The latter is IMO the "deeper" problem: you could add a new observation that allows an FTL signal or maybe the exotic matter required for an Alcubierre-style warp drive is suddenly observed. That would still require relativity, specifically the experimentally well established time dilation aspects, to be grossly wrong.
So the idea of this question is to ignore the first impossibility for now and look soleyly at the second one.
There's a reason I ask this here, not on Physics: An SF Author can apply an infinity of handwaves to tell their story. This question hopefully helps those who for whatever reason *don't* want to handwave relativity away.
Or to put it yet another way: If one breaks relativity as we know it in an SF story, the story ceases to be about an unlikely future and starts to be about an alternate universe. There's nothing wrong with that, it's just not what I'm going for.
p.p.s. This, by [Demigan](https://worldbuilding.stackexchange.com/users/48354/demigan), ist too good to reamin hidden in the comments:
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> I never understood why this is a paradox. It is so easy to describe what happens that you do it right here! Bad shrimp->message->return message->doesnt eat shrimp->doesnt send message (somehow creates a problem with her own timeline), recreates the old timeline where she eats bad shrimp. Cause and effect, clear and simple (except for the twist where not sending the message recreates the old timeline. Why would it?).
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[Answer]
First of all your issue isn't FTL travel, your issue is time travel. In theory if you can teleport from one world to another you have FTL but not time travel, you're linking them but that's ok.
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> Whenever a paradox could arise, the universe splits into two (or maybe
> more) more or less internally consistent universes
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A good way to think of this is there's an infinity of multi-verses, the universe is always splitting or merging an infinity of times. What happens in one multi-verse can affect another but doesn't have to.
If you have the technology to send messages to your cross time selves, then getting warnings about things that don't or even never happened won't be a big deal.
This means you can get warnings that are totally irrelevant to your current situation. The spaceship that gets the message warning about Alice eating bad checks and there is no Alice on board. So the timeline that sent the message was serious but was too far from the current one to be relevant.
Or it is relevant. However the characters can't be sure the messages were sent with good intentions (Alice's sister is trying to do something sneaky, or even Alice#2 is trying to steal Alice's boyfriend because her own died).
If it takes a starship to invoke this problem then presumably it will only happen with serious things... but scale these issues up to a society and we'll find out that governments can lie, pull sneaky deals, and so forth.
That matter duplicating thing you're talking about isn't a downside, it's the creation of a villain.
[Answer]
I’m on a mobile device so my answer is brief here.
A multiverse allows for FTL of a sort.
The catch is, you (the FTL traveller) can never return to the previous universe. Nor can anyone or anything else. Not even a photon.
The problem of calling it FTL is that there’s no common framework, so it’s not “Fast”, and it’s therefore not really FTL, even though it may appear to be. It’s merely switching or hopping from one universe (where planet foo-foo is far away from your boat) to another universe (where something that looks like planet foo-foo is close to your boat).
The key is that there’s no return journey. You can go to somewhere that looks like home - maybe down to a fine level of detail - but it’s a different universe.
Of course, even when you come back from the office (in pre-covid commuting), your home is not the home you left - our own experience of an unchanging world is a necessary fiction - but to talk about universe hopping, there’s a continuum break.
There are other issues with multiverse hopping : one of purpose / choice. Since you can choose a universe where planet foo-foo is filled with bananas, or where it is filled with apples - why bother? Just hop to a universe that suits you ( until it doesn’t, of course ) - but then that is Alladin’s genie/ get a wish stuff.... and as everyone says, you may as well switch FTL with MAGIC.....
You will have to find some sort of energy conservation ( and a shedload of other problems) to enable universe hopping - but I leave that to you as an exercise!
[Answer]
Yes!
There are some physicists who have proposed exactly this: closed timelike curves (a more technical name for a specific kind of time travel that might be allowed by general relativity) create alternative universes which exist in quantum superposition.
From [Wikipedia](https://en.wikipedia.org/wiki/Quantum_mechanics_of_time_travel):
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> In 1991, David Deutsch came up with a proposal for the time evolution equations, with special note as to how it resolves the grandfather paradox and nondeterminism. However, his resolution to the grandfather paradox is considered unsatisfactory to some people, because it states the time traveller reenters another parallel universe, and that the actual quantum state is a quantum superposition of states where the time traveller does and does not exist.
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And the idea that the FTL drive vanishes into a sort of warp bubble not only makes the storytelling easier, but also is more consistent with these speculative ideas from physics (although for verisimilitude you might want to call it a *transient wormhole* rather than a *warp bubble*).
[Answer]
Here are some common theories that allow two-way FTL that can solve your antitelephone problem. It is important to note though that nearly every field of theoretical physics has actually ruled out the possibility of time travel, and maintains that IF superluminal travel is possible, that you will not actually be able to go back in time. If you can not go back in time by exceeding the speed of light, then there is no antitelephone effect, and therefore, no paradox to worry about.
## Using Tachyon Particle Theory
According to the Tachyon Particle Theory, speeds of >1C are possible when a particle moving at 1C hits a negative slope in spacetime; so, single-directional FTL is entirely possible according to the rules of relativity. That said, two-directional FTL is not. If you send a tachyon at 2C out to a relay and bounce it back, then the return signal would max out at 0.5C (as perceived from the original reference frame) because it must fight against the spacetime gradient which you used to your advantage on the way there. This means that the return signal of an antitelephone cannot actually arrive back at the sender before he sends it making the antitelephone impossible, and therefore, causality violation is also impossible.
Professor Erasmo Recami's paper titled [The Tolman “Antitelephone” Paradox: Its Solution by
Tachyon Mechanics](https://cds.cern.ch/record/287288/files/9508164.pdf) offers a much more detailed explanation of this.
To achieve 2-way FTL, the multiverse model introduced by Plate Theory might work for you. My understanding is that it allows for a multiverse of universes that may or may not have the same alignment of spacetime. If you assume your universes do not have the same alignment, then you could fall down the curvature of spacetime in this universe, then you punch through to another universe (or maybe to the back of our own universe?) where you are at a high point, and then ride that down to where you can punch back into our own reality. Now you have two-way FTL.
This is all very theoretical, but I believe this may still resolve to not arriving before you left because in the other universe, your relative relationship with space time in our universe is upside down; so, while you are going slower in time in the upside down, you are going faster in time relative to our universe. This way you can in theory break the light barrier in two directions, but still not come back in the past; so, causality is safe.
[](https://i.stack.imgur.com/9tpOL.png)
One caveat here is that it this system of FTL makes arbitrary warp drives (as in Star Trek) impossible by any means I can think of off of the top of my head. Your ships will need to travel along natural "warp-lanes" where the universe already has strong gradients, or they will need to use some kind of crazy future tech that allows them to manipulate the curvature of space on an interplanetary scale.
## Using Wormhole Theory
Wormholes are allowed according to the laws of relativity, but they do not create causality issues because they are not actually FTL travel. They are just shortcuts that allow you to take a quicker path. Wormhole theory is based on the idea that a universe can be folded in such a way that what appears to be a straight line, but is actually not, and that you can move between two point by taking an "actual" straight line which would be the wormhole. Because your speed never exceeds 1C, your time dilation stays positive; so, you can travel distances greater than light moving through normal space while actually going slower.
[](https://i.stack.imgur.com/nj8Pz.png)
Like the tachyon issue, wormholes must rely on a preexisting condition in spacetime since you cannot move the mouth of a wormhole faster than light.
Wormholes do not need a multiverse to exist, but they do rely to a degree on plate theory; so, a reality where wormholes exist generally allow for the existence of some sort of multiverse.
## Using Quantum Entanglement
This is an interesting one in regard to spacetime because it pretty much violates everything spacetime says should probably be possible, but it's completely and repeatedly proven in laboratory experiments. Einstein himself eventually accepted that it really does happen, even though it seems to contradict his theories.
The way Quantum Entanglement works is that when you generate a pair of particles, they will continue to share mirrored images of the same quantum state indefinitely, even when separated by massive distances. This seemingly allows for instant long ranged communication of information since one should be able to manipulate the quantum state in one particle and observe the outcome instantly in the other.
The most common attempt to justify this while preserving the laws of relativity I've seen is the node (or "boiling space time") model which says that as you approach the quantum scale, spacetime stops looking smooth like a cartesian plane, but instead becomes a complex web of connecting nodes of various lengths and vectors that average out to what we perceive at the macroscopic scale. It this model, space time is not a coordinate system at all; so, to say a distance in perceived space is 1-inch is to actually say that there are an average of 1.572E+33 nodes between two points but that there may be a single node that actually spans the whole distance.
What this means in terms of the speed of light is that the speed of light is not so much ~299,792 cartesian kilometers per second, but ~1.855E+43 nodes per second. Like wormhole theory, this allows one to take shortcuts through spacetime if you know how to find the optimal path. In this model, any particle pair is permanently adjacent, but its other nodes change as they move through space. This means that if you put an emitter at a mid-point between two distant locations, you can have people at either end stimulate the passing particles for instantaneous communications.
This, like the wormhole method, does not violate causality because the communication is not actually exceeding 1C. Here, your two distant points are also adjacent; so, as long as you do not exceed a motion of more than ~1.855E+43 nodes per second, your time dilation stays positive regardless of how far you've seemingly gone; so, there is no antitelephone effect.
This method does not require or suggest the existence of a multiverse at all, but if you want to have a multi-verse, it does not really disprove its existence either.
## Using a Unified Field Theory
Now this last method is controversial as hell, I know the OP does not want to hear it because he does not like its implications on what it means for the theory of relativity, but the point of this list is to give solutions, not to tell him which one he needs to use for his story. Most physicists agree that a Unified Field Theory exists, but they can not agree on what it should look like because we can not separate perception from observation when measuring reality; so, they continue to use relativity because it models well in most practical cases.
The general premise of all unified field theories is that relativity can be described in terms of newtonian physics, or vise versa.
The most common approach is to try to resolve relativity in terms of newtonian physics. This usually relies on explaining that time does not dilate, but that doppler effects and rate of atomic activities change as forces are applied to moving objects. Thus, relativity is a perception of reality and not a literal interpretation. Like relativity, Unified Field Theory typically has to resort to non-cartesian space to explain quantum entanglement.
**An example of explaining the antitelephone problem with a Unified Field Theory might look like this:**
The perception of an FTL ship would present itself much like sound does when exceeding the sound barrier. At >1C, you would see it in reverse because the light reaches you slower than the source, but the thing is still moving forward in time. It could also explain atomic processes as slowing down as a thing accelerates because a portion of the rotational energy in an atom is converted to kinetic energy slowing down how fast it can do the things we measure as time. Relativity in a case like this is an illusion or side-effect of how we perceive and measure reality, and not actually a measure of reality itself.
Unified field theory explains the light speed barrier as a soft cap whereas relativity explains it as a hard cap. In Newtonian physics, a thing can not move something faster than it is already going; so, in a universe when light/gravity is the fastest you can exert a force after releasing all potential energy, there is nothing faster than light or gravity to accelerate something with.
According to Newtonian models of Unified Field Theory, to exceed 1C, you need to impart matter with energy that can not possibly be absorbed from interacting with the physical world. But, if you could impart this impossible energy on matter, then you can use it to not just add unaccountable velocity to your atomic nuclei, but you could also use it to add unaccountable velocity of your electrons allowing you to continue experiencing time in the right direction as you travel faster than light, but the antitelephone effect does not work here because the perception phenomenon does not actually allow for negative time dilation. A negative value in this case would represent electrons moving at 1C and atomic nuclei moving at >1C. If such a thing were possible, it would just mean your electrons could no longer keep up with your nuclei so your matter gets ripped apart as you are turned into plasma... at which point causality is the least of your worries.
Using this method, you could use a multiverse as an excuse to find something faster than light (the fastest thing in our universe), to give your ship or messages an FTL push without making time go backwards.
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> My question is: Do the preceding paragraphs make sense or is there a serious flaw in my thinking?
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Yes. There is a flaw in your thinking. You are assuming that traveling FTL means that you are also traveling back in time. In reality, FTL is impossible. You can't travel faster than light. But if you could, given that time dilates and reaches 0 at the point of the speed of light, it starts going backwards once you exceed it, and thus your paradox is born.
But science fiction doesn't need to care about that. Like I said, FTL is impossible anyways, so the best way to resolve your problem is to say that *your* FTL doesn't go back in time. This way no one can go back to the past and no one can send messages to the past. And doing it this way, FTL without time travel, is a sci-fi staple. It's fine if you decide that, in your setting, FTL is not time travel.
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The Apex predator of the Sea of Grass biome from planet Andromeda is mostly bipedal, but capable of facultative quadrupedalism, it has long limbs, powerful claws on its hands and is roughly the size of an utahraptor, but with a neck that can be from twice to thrice as long. It is a pursuit predator, running after its prey (which usually has similar size or is slightly larger) on all fours until it is close enough to it. It will then hold it with its forelimbs while using its Jaws to slice chunks of meat off until it can no longer run away. Its neck is usually very close to the body, like a [green heron's](https://www.google.com/search?q=green+heron&client=ms-android-samsung-gn-rev1&prmd=ivsn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjyxIaV-LboAhVoLLkGHbHhB8oQ_AUoAXoECBYQAQ&biw=412&bih=718&dpr=2.63), extending only once it has a hold of its prey, in order to bite at more strategic places. Its Jaws, on the other hand, are toothless, being composed of bladed, self-sharpening plates much like those of the dunkleosteus, which are meant for cutting pieces of swallowable size.
Now, could such Jaws be used alongside a long neck? I feel like it would need strong muscles to hold the head like terrorbirds did, but I'm not sure if such fearsome Jaws would truly work well with an "extendable" neck. It's cranium has a crest on its back, serving as an anchor point for muscles while making its head similar to a long snouted dunkle.
[](https://i.stack.imgur.com/SoFsC.gif)
[image source](https://tumblr-amnh-org.cdn.ampproject.org/c/s/tumblr.amnh.org/post/140467924529/wow-its-friday-have-a-great-weekend/amp)
NOTES: Its planet has Earth-like conditions, safe for a slightly denser atmosphere, and its main habitat is composed of plains much like the African Savannah, except for larger, yet more separated trees. Prey is composed of creatures very similar to earth's ungulates.
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You can, but it has other bigger problems, but maybe fixable ones.
You can make the neck as long as you want, but be aware the longer you make the neck the weaker it becomes, so if you make it too long they can't use any force from the neck to assist in biting and tearing which makes it pretty poor for attacking large prey. The design itself is really not that different than any beaked predator, most predators that attack with the head swing the skull up and back as part of the bite, vertebrates just have the pivots at the spine. The shape of the "beak" is what determines how effective it is for hunting, and beaks are horrible for taking a "bite "out of prey beaked predators rely on tearing or being much larger than their prey, and that is the type of "beak" dunkleosteus has, those tall pointed blades in the front work the the fangs of toothed predators or the hooked beaks of birds of prey, they pierce and give anchorage for tearing off pieces of flesh, they will not be good at slicing.
You need a sharp serrated surface to cut a chunk of flesh out, although even then it is slow and requires a lot of sawing motion. So modify the shape of the "beak" and don't make the neck too long and you are plausible. The green herons neck is probably too long, I would says restrict yourself to about 2/3rd that length but it is not unbelievable.
Otherwise leave the beak the way it is and put a shorter stronger neck on it to tear with.
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If the head has the full set of bones that a Dunkleosteus had, then there isn't any reason why the jaw system must be attached directly to the torso
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**Practically, not long at all**
Theoretically, the neck could be pretty long, as there's no biological reason why you can extend a neck out far, even with the Dunkleosteus's unique jaw mechanics. Practically, you don't want to extend it at all. Take another look at the way the jaw functions - it *needs* those back set of plates (the thoracic shield) in order for the jaw to function properly which means that the head is going to be set inside of a neck larger than it. Not such a problem for the Dunkleosteus, which is a fish, and thus doesn't really have a neck - the head is sunken into the main body. Given that a neck larger than a head is impractical (read: the neck is a massive vulnerability on any living creature which is why it's usually protected as well as possible) and this means that, from an evolutionary standpoint, your creature really wouldn't have a neck to begin with,
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I been trying to imagine what it would be like to move around a small moon, around the size of Saturn's moon Iapetus, which possess Earth-like gravity on the surface. I recall reading an xkcd article on an asteroid the size of the Little Prince and the effects of it having 1 g gravity and I wonder if this moon is small enough for tidal forces on people to be notable. I also wonder if the escape velocity have been lowered enough for a car to achieve it. This leads to me to wonder what driving on it would be like, would the curvature be noticeable?
The radius of Iapetus is 735 km (see [here](https://en.wikipedia.org/wiki/Iapetus_(moon))).
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The force of gravity on a spherical body like a planet or moon is governed by Newton's laws. If a moon had the same surface gravity as Earth:
\begin{equation}
F\_{gravity} = \frac{G\*M\_{earth}\*m\_{object}}{r\_{earth}^2} = \frac{G\*M\_{moon}\*m\_{object}}{r\_{moon}^2}
\end{equation}
Solving for the relative density of the moon and subbing in the info for Earth and the radius of Iapetus provided by Google:
\begin{equation}
D\_{moon} = \frac{D\_{earth}\*r\_{earth}}{r\_{moon}} = \frac{5.51 g/cm^3 \* 12,742 km}{1,469 km} = 47.8g/cm^3r
\end{equation}
Taking a quick look at a density table [1], this puts it well above Osmium and Iridium and into the realm of exotic matter, probably involving temperatures and pressures that would be fatally unfriendly to humans and conventional life support equipment. Odds are this moon would have a core of transuranic materials which would explode in an uncontrolled fission reaction as soon as the moon accreted. There's no liquid dense enough to comprise a significant portion of the moon's surface (at reasonable human-friendly pressures and temperatures), so no noticeable tides. And escape velocity is tied to surface gravity, so it would be the same as on earth. No driving off the planet.
[1] <https://en.wikipedia.org/wiki/Talk%3AList_of_elements_by_density/Numeric_densities>
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From this [link](https://en.wikipedia.org/wiki/Tidal_force) we know that **Tidal force** is defined like so:
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> In celestial mechanics, the expression tidal force can refer to a situation in which a body or material (for example, tidal water) is mainly under the gravitational influence of a second body (for example, the Earth), but is also perturbed by the gravitational effects of a third body (for example, the Moon). The perturbing force is sometimes in such cases called a tidal force (for example, the perturbing force on the Moon): it is the difference between the force exerted by the third body on the second and the force exerted by the third body on the first.
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So, straight off the bat we see the Earth-Moon example. Keep in mind that the Earth is many times more massive than the Moon, and the Moon is many times more massive than Iapetus.
So let's look at some basic info about Iapetus that is relevant to your question using info from [here](https://en.wikipedia.org/wiki/Iapetus_(moon)). The surface-level gravity on Iapetus is 0.223 m/s2, or roughly 0.2 Earth Gs. Escape velocity is also pretty low - 0.573 km/s, or 573 m/s (Earth's escape velocity is 11.186 km/s). This means that although you can't just jump and fly off into space, it won't take much. In fact, if you're in a car-shaped rocket on a flat, race-track like patch of land (approximately tangent to the overall curvature of Iapetus), you could very likely accelerate right off the moon on the end of the track. The fastest car on Earth is the Hennessey Venom F5, at 301 miles per hour (or 484.413 km/h). But this is on Earth, where air-friction is a thing and let's not forget the mass of the car, which is a large part of why a car travels fast at all (and I'm not even going to talk about downforce). So, if we instead attach a rocket at the end of this vehicle (not even a massive one, just like the kind used in missiles), we'll be off-world in no time.
**TLDR:** Iapetus is too small to affect anything even the size of a car with tidal forces. [Iapetus does, however experience tidal forces relative to Saturn](https://www.eurekalert.org/pub_releases/2010-12/wuis-hig120710.php). If you want to get needlessly technical about definitions, everything has a tidal force on everything because gravity affects objects even at infinity, hence there must be some perturbations - just not any noticeable ones. I know most of my answer didn't even deal with tidal forces, but perhaps the info I gave you will spark other ideas. I hope this helps!
**Edit:** @Hypnosifl pointed out that you were looking for info on a moon LIKE Iapetus, but not actually Iapetus, specifically if it has a greater mass. More specifically, we're talking about a planet like Iapetus that has the gravity of Earth somehow. This is given by the equation:
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> g = GM/r2
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Now *g* here is equal to one of our Gs (9.8 m/s^2), but *r*=735 km. With some quick maths, M must be equal to: 7.9373388306×1022 kg. This is no moon at all, and must be made completely of some unrealistically dense material! This object must be spinning really fast, so fast that it's tearing itself apart, and nothing could possibly last long on its surface, regardless of the 1G it has. That kind of eliminates the question of tidal forces or anything. An Iapetus-sized object that has such a high value of G is pretty unrealistic, even in scifi. Let's assume it's ridiculously dense as described in the comment. At this point I'd like someone who knows better to please chip in as to my knowledge, I know that tidal forces won't be what you need to worry about, but I know what it would be.
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I have a civilization that lives on a planet located inside a nebula (and orbiting a normal, sun-like star).
Would this nebula somehow interfere with/ obscure the sight of a rogue neutron star/ black hole coming their way? I'm hoping the answer is yes, so that by the time they notice it, it's too late.
If not, is there somewhere else I can place the planet that would more convincingly obscure the sight of the intruding black hole/neutron star?
Thank you!
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Cool idea!
I have to think an incoming black hole would be hard to detect. A big one will give off minimal radiation because it is a black hole. A small one might give off Hawking radiation you could detect if you were looking in the right way. We could detect a rogue black hole by new gravitation lensing of stars on the far side of it; as that distant light passed near the incoming hole it would bend in an uncharacteristic way and the stars in that region of the sky would seem to have shifted position relative to one another. If your people live in a nebula, the more distant stars might be already obscured / refracted by the nebula so it would be harder for them to notice the difference.
Nebulae have stars inside them and those close stars will be easier for your people to see. If the black hole interposes itself between the planet and a star that star will seem to disappear. They might start to catch on that something was happening.
An incoming black hole will certainly suck in the gas of the nebula. If this is an emission nebula the concentration of glowing gas whirling down the drain of the black hole will make that area of the sky brighter and give away the presence of the hole. If the nebula is just dust this will be more difficult to notice. Even dust might glow as it heats up during its descent into the hole.
Once the black hole gets close enough to the system to start messing with orbits your people will definitely detect it. Things are going to get bad fast for them.
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The universe described in the [orthogonal series](http://www.gregegan.net/ORTHOGONAL/00/PM.html) is one, in which the minus sign in the space time interval is replaced with a plus sign. So this universe has four fundamentally similar dimensions rather than three space like dimensions and one time like dimension.
In the universe described in the [orthogonal series](http://www.gregegan.net/ORTHOGONAL/04/EMExtra.html) the electric force between two electric charges is attractive at some distances and repulsive at other distances. The electric potential energy between two electric charges in the universe described in the orthogonal series would be $$U\_E=-\frac{cos(\omega\_mr)Q\_1Q\_2}{4{\pi}r\varepsilon\_0}$$ with $Q\_1$ and $Q\_2$ being the electric charge of each body, $r$ being the distances between the two bodies, $\omega\_m$ being a constant that depends on the rest mass of the photon, $\varepsilon\_0$ being the electric constant, and $U\_E$ being the electric potential energy between the two electric charges.
In our universe the Schwarzschild Metric can be described by the equation $${\Delta}s^2=\frac{{\Delta}r^2}{1-\frac{2GM}{c^2r}}-\left(1-\frac{2GM}{c^2r}\right)c^2{\Delta}t^2+r^2(\Delta\theta^2+sin^2\theta\Delta\varphi^2)$$ with $s^2$ being the spacetime interval between two events, $G$ being the Gravitational Constant, $M$ being the rest mass of the massive body, ${\Delta}r$ being the distance in space between two events in spacetime relative to the massive body, $c$ being the speed of light, ${\Delta}t$ being the time passed between two events in spacetime relative to the massive body, $\theta$ being the colatitude, $\varphi$ being the longitude, and $r$ being the distance to the massive body. I noticed that $$\frac{2GM}{c^2r}$$ has the same relationship to distance as the electric potential energy between two electric charges, in our universe, as well as the gravitational potential for a massive body in newtonian physics.
In a universe with the same spacetime metric as the one described in the orthogonal series, but with massive gravitons, would gravity also be attractive at some distances, and repulsive at other distances?
I was thinking of a universe, with the same space time metric as the universe described in the orthogonal series, but with massive gravitons, and with gravity being repulsive at the closest distances.
In this type of universe, would this be the correct schwarzschild metric?
$${\Delta}s^2=\frac{{\Delta}r^2}{1-\frac{cos(\varrho\_mr)2GM}{c^2r}}+\left(1-\frac{cos(\varrho\_mr)2GM}{c^2r}\right)c^2{\Delta}t^2+r^2(\Delta\theta^2+sin^2\theta\Delta\varphi^2)$$
In this case $\varrho\_m$ would be a constant, that would depend on the mass of the Graviton, and while all dimensions would be fundamentally the same, the world line of the massive body would be treated as the time axis.
Would this be correct for the Schwarzschild Metric for this type of universe?
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I would like to address several problems in your question.
* If flat spacetime had a Kronecker delta metric instead of the usual Minkowski metric then the "invariant" spacetime interval wouldn't be invariant ( if you are still thinking of $t$ as time, otherwise it's an invariant space distance). Also while defining a spherically symmetric metric in spacetime one initially writes a general metric:
$$ ds^2 = A(r) dt^2 + B(r)dtdr + C(r)dr^2 + r^2d\Omega^2$$
Then the terms can be rearranged in the form
$$ds^2= A'(r)dt^2 + B'(r)dr^2 +r^2d\Omega^2$$
This can be done by considering (+,+,+,+) signature but time loses its uniqueness. There wouldn't be any difference between $r$ and $t$. In your universe there is not any difference if one changes $t \leftrightarrow r$. Basically by introducing (+,+,+,+) signature you have removed the concept of time from your universe.
* A massive electromagnetic field has many problems. First of all any massive force field will have to be short ranged because of the [Yukawa Potential](https://en.wikipedia.org/wiki/Yukawa_potential) term. This force will be limited to very short distances. Massive electromagnetic field will also break the internal gauge symmetry. Though this can be avoided by coupling it with a massive scalar field. The similar problems will be faced when working with massive gravity (see [this](https://en.wikipedia.org/wiki/Massive_gravity)).
* When you introduce mass to a spin 2 field, it no longer follows the Einstein field equations anymore. It will follow a new set of equations given by the action for the ghost-free de Rham-Gabadadze-Tolley massive gravity. Solving this will give you a completely different answer. So you can't say that the new Schwartchild metric is given by the metric in the question, it will be totally different.
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**What I'm using your information for:**
My planet is small, has a thicker atmosphere than earth and it's orbiting a white dwarf. The main reason I chose it to be a white dwarf is that I read somewhere that these would take much longer to cool than a regular star, because they have a much smaller surface. The reason I need the star for such a long time is, that I want to communicate how unlikely it is that an intelligent alien species similar to ours would evolve. The time between humanity and my alien species should feel like an eternity. At the same time my species is one of many thousand similar ones that lived on that planet one after another. The whole ecosystem stayed roughly the same and just this one species gets replaced every few 100'000 years. -This process should go on for as long as possible.
**What I want to know:**
The main reason I won't do my research without you is, that I'm really really bad at it: The white dwarf I'm "looking for" should burn its energy as slowly as possible. That's why my planet will orbit quite closely to it, still allowing my ecosystem to exist. It should also have the biggest mass possible and look the same over a long time which (I think) means, that its spectral light will rather be white than blue? -Here's where it ends for me.
* Does the light of the white dwarf I need look differently from each angle than that of our sun? How?
**Edit regarding the comments:**
To L.Dutch. Yes, it's tidally locked.
To AlexP. I could imagine that dead ends in evolutionary lines are possible, if the conditions are right. Our way of evolution isn't the only possible anyways. I even wanted to explain parts of it: There's a bacteria-like species that lives in almost every organism. Rumors tell that an intelligent species that lived long ago had developed them to make certain species go extinct for ever. They support the organs of all rather complex species, also their breeding chambers...
To your second comment: I never thought about it this way... Species evolving that have comparable sight to us will see their suns color as white anyways. Everything else would depend on the atmosphere and the weather... Thanks.
To Alexander: Exactly.
To Stephen G: I understand what you mean. Why would someone care about the sun, when the main problems are asteroids, the rotation of a planet, the planet cooling down, etc? - There's another bigger planet orbiting the white dwarf blocking/pulling asteroids away. The planet will be heated by the same other planet whenever it comes by, like Titan, just less often. The species aren't like the ones we have on earth. Most of them are able to live for thousands of earth-years and they don't reproduce how "we" do. (would take long to explain) Everything else can be explained by luck or "not talking about it", I guess. The longer the sun stays the same, the more likely it is that there's a very long window where also everything else is in place for the stagnating environment I want my stories to take place in.
to cmm: thanks. Now there's only the "main question" remaining.
to TheDyingOfLight: "universe sandbox" looks really interesting. Thanks for the link.
to Mike Scott: Thanks! Such info was exactly what I was hoping for. Hopefully I'll find a way/an example to explain this...
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How the sky will look depends on the light of the star, the consistency of the atmosphere, and the weather. You have given clues to each of these in your multi-part question.
The starlight will be "white" to any visual system that has evolved in that illumination. We see white light because our experience of "white" is that "white" is the color of natural light from which nothing has been removed. If the sun were cooler, or hotter, the spectrum would change, but eyes which evolved in that spectrum would see it as white.
Your planet's atmosphere is denser than earth. The atmosphere may need a generous quantity of greenhouse gasses. If the star is to last longer than the earth's sun, it would use fuel more slowly, and the emitted energy would be lower. Up to a point the lower stellar output can be compensated for by being closer to the star, but an atmosphere of greenhouse gases helps a lot. You can't be too close to the star or your planet will be ripped apart, so greenhouse gasses may be a friendlier alternative.
The weather is trickier. You say that nothing changes in the ecology, which must mean that mountains aren't growing, the seas aren't changing, and the climate is consistent. I don't know how to do that. Wind and rain cause erosion, which cause change. I think you might need to give up on you "constant ecology", and make something more like earth, with a dynamic balance between growth and destruction with species evolving in competition with others, and species disappearing as they fail to adapt to changes. It would be more likely that your succession of intelligent species could evolve in such a dynamic relative equilibrium that in a world that is completely static.
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There is a scientific paper titled "TRANSIT SURVEYS FOR EARTHS IN THE HABITABLE ZONES OF WHITE DWARFS" by Eric Agol that focusses on the possibility of habitable planets orbiting white dwarfs, and it has quite a bit of information that you may find useful.
In it he claims, although he does not show his calculations, that the star would appear to be of a very similar apparent color and apparent size in the sky to that of the sun, if the planet was orbiting at the optimal position for the planet to be habitable for the longest possible time, which he concluded to be at an orbital radius of approximately 0.01 AU, which, yes, is tiny, but white dwarfs are very dim.
It is also worth noting that the more massive a white dwarf is, the *smaller* it's radius, up to an optimal mass of approximately 1.44 solar masses, at which point a white dwarf will collapse into a neutron star. However, whatever your atmospheric composition is will likely affect the apparent color of the star, so you may need to take that into account.
One side effect of having a planet orbit a white dwarf star that you may not realize is that, because white dwarfs produce either very little (if the white dwarf is extremely young) or no solar wind, which results in there being no Auroras.
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[Question]
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I was thinking of a life form with a similar surface temperature to Earth, as well as a similar temperature variation to that of Earth.
Could such a life form evolve an organ for generating temperatures a fraction of a degree Kelvin above absolute zero? If so how might such an organ work, and what types of selective pressures might cause such an organ to evolve?
[Answer]
If you follow my answers, I really love to answer with "yes, nature loves to do all sorts of awesome things," and then link to some strange creature that does things you'd never expect possible.
This is not one of those answers.
The temperatures you describe are simply not accessible in the way you seek. They can't be achieved as an organ.
The first issue is the vacuum. One challenge with things that are as cold as 1K is that a single collision from a gas particle can raise its temperature well beyond 1K. When we get atoms down to below 1K, we do so in a vacuum chamber. Now this is not a "suck on the soda straw" type of vacuum. Atmospheric pressure is 760 Torr, where Torr is a unit of pressure. A human sucking on a soda straw can get around 500Torr. That's nothing. Get down to 21 Torr, and water will boil at room temperature.
The kinds of vacuums they use to get below 1K start on the order of 0.000000001 Torr and go down from there. At that point, gases stop acting like gasses, and start acting like little billiard balls bouncing around. When you learn about turbomolecular pumps, they are described as being less like a fan that pumps air out of your chamber and more like a carefully crafted set of baseball bats designed to strike individual atoms and push them towards the high pressure side where you can suck them out.
All sorts of strange things happen at those pressures. Anyone who works with ultra high vacuums like that knows the aphorism: everything outgasses. A single fingerprint can prevent you from reaching your goal pressure for weeks, simply by the oils in the fingerprint turning to gas, forcing you to pump them out.
You run into all sorts of fun issues constructing these things. You can't make them out of normal steel. Hydrogen can actually pour through mild steel, ensuring you never pump down. Modern vacuum aparatus are made of stainless steel. Not just any stainless, but a very particular alloy called 304L, and reasonably thick as well. So your "organ" now has to contain a stainless steel chamber at least 0.1" thick (quarter inch is common), made to the high standards of modern steel. It also needs to be produced in a way that doesn't leave a bunch of cells inside the wall, like how skin is a bunch of dead cells. It then needs to be cleaned with a whole bunch of chemicals: acetone and isopropyl alcohol are common.
We usually then bake vacuum components. Yes, we want to get to low temperatures, but we have to hit high temperatures first to help bake out anything that will outgas later. We might target 120C, well above the boiling point of water. Not enjoyable for an organ!
Once we assemble it, we have to pump it down. For this we tend to start with Turbomolecular pumps that spin at 90,000rpm, and then work our way down to exotic things like ion pumps and cryo pumps. You tend to need to use several pumps in tandem as they each have their own strengths and weaknesses. Even for a small chamber, this will easily use up 500W or more. This tells us something about the size of the creature. Expending 300W continuously is more or less the limit of a human body, so this creature most certainly is bigger (or at least more energetic) than we are. This will call for expending at least 10,000 Calories every day, for many days in a row. If this energy was stored as fat, that's one heck of a weight loss plan, as you'll lose about 3 pounds of fat every day just trying to keep this thing going.
And we haven't even gotten it cool yet.
We tend to rely on gasses to cool things down. Liquid nitrogen is useful to get down to 78K. But getting beyond that requires other gasses. Typically Helium-3 is used when trying to get down to ultra low temperatures. Note I said Helium-3. There's two isotopes for Helium: H3 and H4. Helium 3 is better because it boils at 3.19K instead of 4.214K. So now we need to get some Helium. Helium is *extremely rare* because it's small enough to simply leave the atmosphere once it gets there. Most of our helium comes from Uranium decay, and the helium gets trapped in natural gas, and its mostly H4. Most of our H3 comes from bombarding Lithium-6 with neutrons in a particle accelerator, releasing H4 and tritium, then storing the tritium until it decays to produce H3.
So our creature needs a particle accelerator, as well as a stainless steel chamber and a turbo pump and an appetite of a Michael Phelps!
Even H3 only gets you down to 3.19K the rest is up to you. You could try to go into the vacuum of space and expose the chamber to the void, but even the background radiation of the universe is too hot, at 2.7K. So you need something more exotic. Atoms being driven towards 1K and beyond are typically suspended in carefully managed magnetic traps, and then cooled with lasers. Now cooling with lasers is one of the neater tricks science has figured out. You've dealt with doppler shift, right? The train sounds higher pitched as it comes towards you and then lower pitched as it moves away? Well they abuse that. They have these lasers tuned such that the laser usually does not excite any of the atoms. However, if the atoms move towards the laser, the doppler shift is enough to cause the laser to apply pressure to it, gently pushing it the other way.
So you need a stainless steel chamber, perfect cleanliness a high speed and exotic pumping system consuming 3 pounds of fat a day just to keep it spinning, controlled magnetic traps, and lasers to cool things. Might as well strap the lasers to a shark, just for good measure.
And for what? There's not much to be gained from 1K and below. Almost anything you do with it raises its temperature. Scientists who push below 1K aren't looking to *do* anything with it. They're looking to learn something about the world around us. You only need a handful of these exotic contraptions around the world. An organ would mean each individual has one of these things. Even the scientists admit there just isn't enough of a use for 1K to go anywhere.
So I want to say "anything's possible for nature." But when you look at that laundry list of things, doing it in an organ is just not a likely path. Instead you'd do it exactly the way we did it -- in non-organic chambers crafted intentionally and with great purpose. And we'd only need a few of them.
[Answer]
Simple answer: nope. An organ like that would require a large amount of energy. If an animal has enough spare energy to have an organ like that, it does not need to adapt an organ like that to survive.
[Answer]
### Nitpicks
Kelvins don't have degrees; they're their own unit.
You don't "generate" temperatures of a fraction of a Kelvin. You cool to that temperature. Temperature is a measure of the average heat. Heat can be generated. Cold cannot. Cold is simply the absence of heat.
### Answering
To create a volume with a temperature of a fraction of a Kelvin, you have to shield that volume from the rest of the universe (the average temperature of [empty space](https://sciencing.com/temperatures-outer-space-around-earth-20254.html) is about 3 Kelvins). And then you have to transfer the heat already in that volume from the volume so as to bring its temperature down. That's difficult.
[This answer](https://worldbuilding.stackexchange.com/a/148522/2113) may well be right that it is too difficult to happen through natural evolution. You would likely need some advantage to more moderate cooling that improves as the temperature gets lower. And it would need to improve something like exponentially, as cooling gets harder the greater the temperature differential.
Links:
* [The Coldest Spot in the Known Universe](https://science.nasa.gov/science-news/science-at-nasa/2014/30jan_coldspot). A NASA project to cool a volume to a fraction of a Kelvin.
* [This is the Coldest Place in the Universe](https://www.seeker.com/this-is-the-coldest-place-in-the-universe-1767977507.html). The coldest naturally occurring location found.
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[Question]
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In lots of barren, deserted or otherwise destroyed landscapes, there are bones of long dead animals to be found. Sometimes, it's a skull, sometimes, these are rib-cages, or ribs alone.
And sometimes, these bones are huge.
Is there any sort of common ratio that can be used to calculate the size of the whole body of the animal dead from the size of the bone alone.
(Or more specifically, suppose I have a rib sticking 500 m into the sky, coming from the stereotypical flying flame-breathing dragon, probably western style (though eastern is fine too). Ignore the obvious "dragon of such size could not possibly fly"; I'm making up a game lore, not a documentary. Also, magic.)
[Answer]
The size of rib varies depending on the general physiology of the animal; an animal with big lungs and a heart is going to need a different rib cage from one with smaller organs; a biped's is going to be different from a quadraped's, and so on.
For comparisons, a blue whale has a rib cage that is perhaps a tad 2 meters deep (not individual rib length) in the biggest animals: here's an image of a man standing inside a mounted skeleton.
[](https://i.stack.imgur.com/DoJJ6.jpg)
This is the largest reconstructed (and sizes mostly estimated) dinosaur skeleton in the world, an *Argentinosaurus* at almost 40 meters long and 7.3 meters tall at the shoulder. Based on those measurements, you can see the rib depth looks like it's about 3 meters for the longest ribs.
[](https://i.stack.imgur.com/iExBe.jpg)
If we project similar proportions, for a rib sticking 500 meters into the sky, you'd be looking at an animal 6.7 *kilometers* long.
That's, um, a lot of magic. For another comparison, the largest sandworms on Arrakis, true monsters, were indicated to be 450 meters long. Godzilla Earth, from the 2017 animated film and the largest version of the Big G to ever appear, was 300 meters tall and 600 meters long.
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I'm working on yet another iteration of a world map project.
I'd like to ask for some opinions on the sea temperature map I've done:
[](https://i.stack.imgur.com/uQ5mo.png)
I also have a few specific questions about some areas on the map.
[](https://i.stack.imgur.com/T8NQ6.png)
**A:** Should there be a warm or cold current here? There is no landmass to divert the equatorial currents northwards but it also seems that the westerly winds between 30 and 60 degrees would defy a current flowing south. There's a big hole in my understanding of all this, I have no doubt :P
**B:** I've mapped this area somewhat like the effect the gulf stream has on western europe, does this fit/make sense?
**C:** I have a feeling this isolated polar sea should be a fair bit colder... would it be more or less frozen over? how much should it be cooling the ocean beyond its two outlets?
[](https://i.stack.imgur.com/Yu64h.png)
Here is an additional Spilhaus projection version of the map, nice visualisation of the ocean as whole.
Thanks in advance and looking forward to discussing with you all in the comments!
Update:
After your responses I revisited the map and reworked it along with ocean currents. Here is the result:
[](https://i.stack.imgur.com/mEwGq.png)
[Answer]
**You could build in currents.**
[](https://i.stack.imgur.com/rLuRc.png)
>
> The path of the ocean currents can be seen on maps of sea surface
> temperature (SST) such as one below. You should be able to see warm
> currents flowing away from the equator on on the western side of the
> ocean basins, and cold water flowing towards the equator on the
> eastern side.
>
>
>
You can see how north moving currents pushes cold water up along the west coast of South America and Australia, and south moving currents push cold water down the west coast of North America and Africa. Having the presence of the continents interfere with your horizontal rainbow of temperature would be more realistic. The linked source has some good basic stuff about ocean currents and temperature.
That said, nice map you made!
<https://seos-project.eu/oceancurrents/oceancurrents-c02-p03.html>
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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.
Human physiology is adapted for life at 1G, but planets colonised by future humans will likely have different surface gravities.
What is the range of values for surface gravity that humans can comfortably tolerate long-term?
**Note:** I am not interested in the absolute maximum gravity that a human could live through, but rather the gravity that would be suitable for a permanent colony.
[Answer]
One way to narrow down the range of acceptable and safe surface gravities would be to read *Habitable Planets for Man*, Stephen Dole, 1964, 2007.
As I remember, Stephen Dole suggested a maximum safe surface gravity for a planet to be colonized in the 1964 edition, no doubt based on space medicine experiments and tests previously done. I doubt whether any later scientific experiments, tests, and theories have broadened any of Dole's standards for habitability since then, and it is more likely that present day scientists have more restricted standards for habitability.
So if Dole says that Xgs are the upper limit for habitability, it is possible that Xgs is correct, but it is also possible that a lesser number of gs would be the correct higher limit for surface gravity.
Chapter 2 discusses human requirements for habitability. On page 12 it is staid that:
"On the basis of the available data, one might conclude that few people would choose to live on a planet where the surface gravity was higher than 1.25 or 1.50g."
<https://www.rand.org/content/dam/rand/pubs/commercial_books/2007/RAND_CB179-1.pdf>[1](https://www.rand.org/content/dam/rand/pubs/commercial_books/2007/RAND_CB179-1.pdf)
And see this question at space exploration stack exchange:
<https://space.stackexchange.com/questions/6154/maximum-survivable-long-term-g-forces>[2](https://space.stackexchange.com/questions/6154/maximum-survivable-long-term-g-forces)
And this one:
<https://www.reddit.com/r/TheExpanse/comments/8arlck/how_many_gs_can_the_human_body_sustain_over/>[3](https://www.reddit.com/r/TheExpanse/comments/8arlck/how_many_gs_can_the_human_body_sustain_over/)
It is said that:
>
> Human volunteers have tolerated 1.5g for seven days with no apparent ill effects. However, after just twenty-four hours at 2g, evidence of significant fluid imbalance is detectable. At 3g to 4g fatigue is limiting, and above 4g cardiovascular factors limit g tolerance.
>
>
>
<https://books.google.fr/books?hl=fr&id=Lqz-4XU5m28C&q=Human%20volunteers%20have%20tolerated#v=onepage&q&f=false>[4](https://books.google.fr/books?hl=fr&id=Lqz-4XU5m28C&q=Human%20volunteers%20have%20tolerated#v=onepage&q&f=false)
And here is a link to a NASA study:
<https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930020462.pdf>[5](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930020462.pdf)
It doesn't seem to cover g forces higher than 1 g sustained for months, years, or decades.
At the present time there is no evidence that a mixed human population with different states of health such as in a colony could survive and thrive while experiencing surface gravity higher than the 1.25 to 1.50g suggested by Dole, and there doesn't seem to be any experimental proof that anyone could survive 1.50g for more than 7 days without adverse health effects.
Obviously the majority of people should have no problems living their lives in 1.01g or 1.02g, but it seems reasonable, based on current evidence, for science fiction writers to say that, in a space opera setting with many colonized extra solar planets, experience has shown that the highest safe surface gravity for a colony planet is somewhere in the range of about 1.25g to 1.5g.
If a science fiction writer claims that the higher safe limit for colony planet surface gravity is about 1.25g to 1.50g, and/or limits the surface gravity of fictional colony planets to less than that, no one should accused him of being unrealistic - in that aspect of his story at least.
Added 01-11-2019. As far as I know the only worlds in our solar system with higher surface gravities than Earth are Jupiter, Saturn, and Neptune, and they don't have solid surfaces.
So the three ways in this solar system to test human long term tolerance of higher gravity are:
1) Put people in balloons at various levels in the atmospheres of giant planets for long periods.
2) Test people in centrifuges for long periods.
3) Put humans in rockets that can accelerate and decelerate at higher than 1g for long periods of time.
Only the second method is plausible in the immediate future so it is possible that the answer to the question might not be known with certainty for decades or centuries in the future.
[Answer]
There's plenty of ways to create a sustainable long term colony in high G environment. It would be very inefficient to ignore colonizing otherwise suitable planets with >1.5G just because of their gravity only.
**Spend most of your time in a pool filled with mercury**
Colonists would spend most of their time in giant pools filled with a high buoyancy liquid when not wearing their g-suit (described below) to rest/research/eat etc...
The buoyancy of that liquid would counteract the gravity and help the colonist with the high G. Mercury seems to be a good choice since it is very dense and not easily absorbed or metabolized. Mercury is 13x denser than our bodies.
<https://nerdist.com/float-mercury-video-science/>
A rough calculation would indicate that you would be able to live on a 12G planet but with an apparent specific gravity of 1G.
Of course this will still have limits but we would certainly be able to colonize planets with >1.5G.
**Use G-suits when you want to work outside the pool**
If we have the technology to travel to other solar systems, we would certainly be able to craft some sort of advanced g suit to offset the negative consequences of >1.5G environments for short times (a few hours).
It already exists for current jet fighter pilots.
<https://en.wikipedia.org/wiki/G-suit>
So all you need is some sort of motorized exoskeleton to help you move around in high G environment and some system to put pressure on the bottom of your body to relieve your cardiovascular system.
Or you could just send drones to do all the outside work and stay in your mercury pool forever.
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[Question]
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Let's say humans moved to Mars and have lived there for millions of years. Mars is of now uninhabitable, though in this case some terraforming has happened. The poles have been nuked to release greenhouse gases and a prosthetic magnetic field has been created, and also an ozone layer. The hows are not important. So, Mars is warm enough for humans, actually quite a lot warmer than on Earth today, and a weak and spotty ozone layer protects from UV-radiation. But not as much as Earth. The UV radiation is that of Earth's equator, just amplified quite a bit. This is due to the low resources going into the project, as the move to Mars happened in a drastic time of war on Earth, meaning they couldn't spend much time perfecting the terraforming process and outcome.
Now that all those details are out of the way, this is the product of my research: I know these martians would be a little taller than the average earthling human. Their skin would also be coal black, along with their hair and their eyes, due to the amplified melanin production to protect against the UV-radiation. I also know they'd be just a little weaker, unless for some reason their diet was more protein filled than that of ours today. So, how else would these Martians be different? What more would the conditions on Mars change about the human body?
[Answer]
The obvious modifications would be reduced bone & muscle-mass due to lower gravity stress.
Reduced solar radiation probably drives a lightening of the skin to produce vitamin D, so the people would become paler compared to earthlings.
Blood hemoglobin counts would vary inversely with whatever atmospheric oxygen level is established, just as happens with altitude on earth.
To the extent that cosmic radiation is permitted thru the atmosphere, within a narrow limit, there would be selection pressure for resistance to skin cancers, perhaps with a thickening of the epidermis layer.
Blue/green eyes might also be selected for in a lower light environment.
Another less predictable modification might be those associated with efficient locomotion in a lower-g environment, where a lower cg might be favored. This would only be germane under an 'in the wild' selection environment, though grace/agility has potential for sexual selection.
[Answer]
# Skin color
I doubt the coal black skin color hypothesis for two reasons.
### Radiation sources and magnitude
Damaging radiation on Mars is going to come from [sources other than UV](https://en.wikipedia.org/wiki/Mars_Radiation_Environment_Experiment#How_the_instrument_works). Mars is 1.5 times farther from Sol than Earth; by the inverse square law, UV radiation will be 2.3 times less than on Earth. On the other hand, Mars' high background radiation, and periodic spikes of deadly radiation, comes from [high energy particles](https://en.wikipedia.org/wiki/Cosmic_ray). When these particles interact with the atmosphere or surface or your body, they will emit a wide spectrum of EM radiation as the high energy cosmic ray particles are lose energy through collisions.
[](https://i.stack.imgur.com/nnlku.jpg)
Second, the overall dose on Mars is too high for humans, as they currently exist, to survive. As seen the picture above, pretty much the entire planet sees at least 10 rem/year from cosmic rays. The [legal limit for radiation workers](https://www.nde-ed.org/EducationResources/CommunityCollege/RadiationSafety/safe_use/exposure.htm) in the US is 5 rem/year. Other potential bad news is that While 10 rem/year isn't necessarily deadly, no one has ever been exposed to a chronic dose of that intensity. It is debatable if or how fast this exposure would cause cancer, and also debatable how well/if at all reproduction would work. For comparison, the legal limit for pregnant women is 0.5 rad during a 9 month pregnancy; Mars would exceed that by a factor of over 10.
Conclusion is, people would not be living outside on Mars. They would be living in radiation shelters. And, if they are living in radiation shelters, there is no evolutionary pressure driving towards coal black skin.
### Skin color is not primarily driven by UV radiation
There is evidence that the skin color gradient on Earth is driven by sexual selection. There is evidence in that linked paper, that men prefer to mate with women who have a lighter skin color. The skin color preference is noted within society groups; that is, men prefer women who are lighter skinned than average in their society, not that men universally prefer Finnish women.
The paper concludes that the gradient in skin colors on Earth is caused by a mixture of factors: skin color preference against the biological advantage of dark skin for UV protection. Given the last point showed that UV expose of Martians is likely to be very low, because of living in radiation shielded environments, I would suggest that skin color is likely to be driven to Finnish white by sexual selection, since there will be no UV related advantage to skin color.
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[Question]
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I [recently asked](https://worldbuilding.stackexchange.com/questions/110131/the-practicality-of-corinthian-style-combat-helmets) about the plausibility of a fully-enclosed modern combat helmet, whose design took cues from the [Corinthian helmet](https://itsallgreeklondon.files.wordpress.com/2015/08/3-bronze-corinthian-helmet.jpg?w=900), [a human skull](http://tvtropes.org/pmwiki/pmwiki.php/Main/SkullForAHead)
and [a scowling face](http://tvtropes.org/pmwiki/pmwiki.php/Main/RageHelm). This "Corinthian-Type Helmet" would have incorporated features such as a vacuum seal, polarised lenses, [tubes connected to a re-breather in the wearer's armour](http://tvtropes.org/pmwiki/pmwiki.php/Main/GasMaskMooks), small lights mounted on the cheek-guards and the helmet's back coming down to collar level to protect the wearer's neck. The concept behind such a design was that I wanted to make the wearer look [intimidating](http://tvtropes.org/pmwiki/pmwiki.php/Main/MalevolentMaskedMen) and [prepared for any combat situation that might occur](http://tvtropes.org/pmwiki/pmwiki.php/Main/CrazyPrepared) while [de-humanizing them](http://tvtropes.org/pmwiki/pmwiki.php/Main/Dehumanization) [as much as possible](http://tvtropes.org/pmwiki/pmwiki.php/Main/FacelessGoons).
I didn't take long for me to realise that the whole "Corinthian-Type Helmet" was an idea that looked good on paper but was terrible in practice, as [kingledion](https://worldbuilding.stackexchange.com/users/23519/kingledion)'s response did an excellent job of outlining this helmet's impracticalities, which included:
* Restricting neck movement and being extremely heavy to wear, due to the sheer amount of electronics contained within the helmet
* Impeding breathing and promoting moisture or bacteria growth thanks to no ventilation
* Limiting the wearer's peripheral vision by allowing sweat and moisture to build upon the faceplate in high-temperature environments
* The faceplate's fragility and inability to withstand damage
**FEATURES OF THE CORINTHIAN-TYPE HELMET 2.0**
* The rebreather and breathing tubes have been phased out in favour of vent holes being incorporated into the helmet's front, crown and back, allowing air to pass through the helmet and stop the lenses misting up
* The faceplate has been replaced with a large pair of rhombus-shaped eyeholes tilted at a 45-degree angle, which combined with a downward slanting forehead shield, make the helmet resemble a scowling face
* The cheek-guard lights mounted lights have been removed and replaced with a [feature that allows the wearer to see better in darkness via switching to night or infrared vision](http://tvtropes.org/pmwiki/pmwiki.php/Main/GogglesDoSomethingUnusual), which can be controlled by the wearer using a [wrist-mounted device](http://tvtropes.org/pmwiki/pmwiki.php/Main/SuperWristGadget)
* Polarised lens projecting a HUD displaying the wearer's vital signs, [a motion tracking sensor](http://tvtropes.org/pmwiki/pmwiki.php/Main/EnemyDetectingRadar) and ammo readouts
* The very end of the helmet's back is shaped in a flipped upward fashion, allowing the wear to tilt it back over their head when not in combat as per their namesake
How practical would such a combat helmet be?
[Answer]
According to Wikipedia article on [Ballistic\_face\_mask](https://en.wikipedia.org/wiki/Ballistic_face_mask) modern materials can provide a IIIA defence at most while keeping it on a weight level that can somehow still be worn on your face (and even that will be uncomfortable), this means that it can protect against handguns & shotgun buckshots but not against rifle rounds, and being a combat helmet what your armor will have to protect against will be most likely rifle rounds which kinda defeat the reason of having it.
For ballistic facial armor (mask or full face helmet) to be any use in modern combat new materials that can withstand the power of a 5.56\7.62 (at least) will need to be developed but just by having said materials you stop it from being modern and go to "20 minutes into the future" at best.
[Answer]
The features you listed all seems well enough. Keep in mind most modern combat helmets are designed to defend against scrapnal and concussions, so the dude's wearing your helmets may be prepared to enter a melee fight at a moments notice. This makes me think they are a police unit or some other force that expects to deal with nearly-unarmed combatants.
Considering intimidation seems to be a key feature of this design, maybe they are part of a totalitarian police force or some kind of highly armed bank robbers? The former makes more thematic sense to me, as fascists love greco-roman inspirations.
The only things I think are worth considering is that the eyeholes might obscure some of the wearer's vision (or not. I only mention it because it could be a plot point) and the 2.0 version doesn't include protection against chemical weapons (which might not be a big deal, depending on what role you want these dudes to have).
[Answer]
eye cover of any kind is always an issue in a combat helmet, it is very east to get it dirty and those who cannot see in combat do not live long. Notice on modern combat helmets permanent eye covers are only for very specialized situations. Covering one eye with a hinged/ removable display might not be a bad idea however. You can include your permanent HUD in the cheek plate.
If you look at modern designs the one thing they share in common is you can flip the display out of the way or yank them off easily if you need too, the risk of obscured vision is a big issue.
[](https://i.stack.imgur.com/FmFqz.jpg)
[](https://i.stack.imgur.com/c6TMo.jpg)
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[Question]
[
**QUESTION:** Would this system of government be effective, and if so (why) and if not (why)?
What I'm mostly looking for here is a reality-check or improvements / observations on how my proposed skeleton idea for a system of government would/could function (either as I intend (laid out here) or in an alternative way (as you see it in your own mind's eye)) based on historical data, knowledge of social engineering, and any creative hypothesis you'd like to share.
In my MARS colony, I intend to have the government run on a parliament-like/senate-like/republic-like system where the primary decision makers(insert important sounding title here) are members of the four primary entities/factions of the colony.
1. **Science** (think STEM) focused group in charge of technological advancement, creation, and implementation.
2. **Mining and Agriculture** focused group in charge of procurement and production of natural resources, food, and water.
3. **Military** focused group in charge of defense, offense, planetary security (as it applies to war, NOT THE POLICE (thank you Admiral Adama)). The Military also has multiple branches: R&D (similar to and originally a part of STEM but with a distinctly military focus), Marine Corps, and Space Superiority.
4. **MISC** (Mars Infrastructure and Service to Citizens) this faction encompasses the largest portion of everything and includes all infrastructure (utilities, mundane construction, waste disposal, police force, emergency services, city planning, political offices, judiciary, medical services (I think you get the idea) etc...)
The governance itself (only talking about the highest level here, I'll deal with the nitty-gritty of city governance and lower at another time) would be composed of a council (think senate) of 14 seats. The Science/A&M/Military factions would each have 3 seats (9 total) with the MISC faction making up the other 5 seats. From there it would operate through Majority Rule.
**Seats would be given out differently in each faction.**
The Military would be lead by its three highest ranking officers from the R&D, MC, and SS branches.
Service Term: 2 years with no officer being able to serve consecutive terms or more than 6 years total. The military is the only political faction that does not require its seat holders to give up their positions within the faction in order to serve.
The STEM faction would be lead by those three individuals considered to have most benefitted the colony as a whole through scientific research, development, or implementation.
Service Term: Life or until abdication to another equally/near-equally recognized individual.
The A&M faction would consist of the two industry leaders (the most senior/influential leading individual within the mining industry and the agriculture industry (one form each)) with a service term of 4 years and one seat to be filled through random selection of "blue-collar" miners/farmers with a service term of 2 years. Industry leaders must give up their positions within the mining and agricultural industries in order to serve and may not decline service. There is no restriction on any industry leader serving multiple terms (an individual may leave the industry to serve for four years, then re-join the industry upon being replaced, rise to prominence again and be called on to serve again). Random selection will never select the same individual twice.
The MISC would fill three seats through traditional democratic election and campaigning (similar to that done in America by political party candidates) where an electoral college consisting of the top official of each Martian City (of which there are currently 18) casts an equal vote informed by the majority vote of all MISC faction individuals (the majority of the population) in their respective cities.
Service Term: 2 years, once elected to office an encumbent may never again run for election. (maximum of 1 term).
The final two seats would be filled by ordinary citizens chosen at random from all voting MISC faction members (again, the majority of the population). These would have a service term of 2 years and could never be randomly selected again, however, they would have the option of running for election through the electoral process at any time. (Those having been elected through the electoral process cannot be randomly selected for these two seats).
**Narrowing the Scope:**
For this scenario assume a semi-perfect world in which resources are plentiful, war is scarce, unemployment is non-existent, and the daily needs for food/water/shelter are being met for every productive citizen in a society that values individual improvement, work ethic, and the advancement of the whole as chief ideals (not socialism, but definitely mixed ideologically) where the chief sins are selfishness (benefitting one's self at the expense of the colony), laziness (not benefitting the colony or improving yourself for the sake of leisure, frivolous pursuits, or distaste for work), and uselessness (those unable to work, teach, or continue self improvement due to mental, biological, chronological, or any other reason).
Additionally, not all laws require a vote from all sitting members of this senate-like body. Laws dealing with items internal to the various factions (military training laws (if raised to the highest level of government) are decided on by the three members of the military) are dealt with internally if they rise to this highest level of governance. However, these laws and decisions made at this level (even if they do not require a complete senate vote) are disclosed in full to all seated members of the senate and their staffs. Any decision made by an individual group (such as the military) that any other faction views as impacting them and therefore requiring their say-so can be changed to a full senate or multi-faction vote through a unanimous decision by another or multiple other factions.
**EXAMPLE:**
The military wishes to change the minimum entry age for recruiting from 18 years of age (17 years of age with waiver) to 14 years of age (13 years of age with waiver) with special allowances for a child to be designated a military service member at birth and be raised in specialized military environments/schools etc...
Originally this controversial change was passed up the chain to the highest levels of the military and ultimately passed 3-0 by the three sitting members of the senate-like body. It was then passed to the staffs of the other factions who unanimously voted that it be raised to a whole-senate vote. It did not pass with a total vote of 6-8 and was sent back with proposed revisions to be re-worked later.
**EXAMPLE 2:**
The A&M faction proposed a new regulatory law that would require all water pipes that pass within 1000 meters of known lithium deposits and/or lithium mining operations to be thickened with an additional outer casing and secondary sealant system in place to prevent potential leakage. After passing this regulation 3-0 it was sent to the other factions' staffs for review.
STEM and MISC both opted to raise it to a partial senate vote while the military chose to abstain. The regulation eventually passed 8-3.
**Further Narrowing**:
There are also specific rules in place concerning total/partial senate votes.
* Any Law/Regulation previously passed by a single faction or partial senate vote may at any time by any previously abstaining faction be brought back to the senate for a full (or more full) vote due to new evidence or unintended consequences of this law/regulation coming to light.
* The military may not vote in any laws/regulations directly dealing with law-enforcement or policing (thank you Admiral Adama).
* A deadlock may be resolved by bringing in an additional faction for mediation and/or voting purposes. Additionally a full-senate deadlock may be resolved through a planet/colony wide majority vote with 3000 voters chosen at random from each the STEM, A&M, and Military and 5000 voters chosen at random from MISC for a total of 14000 votes with a 70% majority requirement.
* A sitting member of this senate-like body may not be inpeached, but rather may be accused of laziness (if proved through whatever means (unimportant to the question) results in being removed from the seat and banned from politics for life), selfishness (if proven through whatever means resulting in 10 years hard labor or the death sentence (convict's choice) upon completion of 10 years hard labor may be eligible again for office), or uselessness (the hardest to prove but results are the same as the laziness clause).
**\* (if your critique revolves around the need for additional rules as opposed to the system as a whole please let me know what they are!)**
* Does this system seem to be self-balancing?
* Does this system seem to serve the individuals in power, the individual factions, or the colony as a whole?
* What should/could be changed to re-orient this proposed system more closely around the ideas/sins listed in the above paragraph?
Again, thank you to anyone who takes the time to answer. I can provide additional refinement as needed.
[Answer]
**This isn't a government, it's merely a council**
This organization would only opperate well if an actual government elsewhere was impossing restrictions on their behavior. Most notably, the military obviously has all the physical power, which makes them difficult to stop if they choose to take control. The science branch perhaps has control over security codes, etc., such that the military simply can't take control ... but it's difficult to know how well they can keep that secred with a soldier holding a sig against their temple. The entire [*Divergent* series of books](https://en.wikipedia.org/wiki/Divergent_(novel)) is based on the same basic concept you've proposed, and what happens when the balance of that council is distrupted.
**Who is being governed?**
You call this a colony, so I assume it has lots of "normal citizens." Janitors and teachers and shop owners and street vendors and secretaries and para legals and nurses and dentists and the many thousands of seemingly less important jobs that are actually the glue that holds a society together. We're tempted to suggest that they're being represented by either M&A or MISC, but the reality is they're not represented by either. M&A is fundamentally a business concern and MISC is a welfare concern. Both are most interested in (a) the procedures involved with their operations (e.g., water access) and (b) securing the resources they need for their success (e.g., water access).
Government is about one of two things: power or people. Medieval monarchies were generally about power. Modern governments are generally about people. Your current structure has no representation for the average person, but enormous representation for the services that control or have power over people. *Viva la revolución!* In truth, your government looks most like the organization of a corporation where the various divisions and departments all vie for corporate resources to fulfill their mandates.
**In an ideal world, representatives represent people, industries and organizations counsel via a cabinet**
Organizations have no choice but to see people as a *resource.* A means of continuing the organization's purposes or facilitating its operations. Anyone who has worked in a large corporation (especially a multi-national corporation) knows exactly what I'm talking about. It doesn't matter if that organizatin is Science, M&A, Military, or MISC (for example). They certainly have needs, and those needs must be addressed for the good of the people — but they cannot be allowed to do it on their own or they will inevitably reduce *people* to a line item on a balance sheet.
All representative governments, no matter how they are organized, have some form of a popular vote. This is how the people balance their individual needs against the needs of organizations.
You are missing this all-important component of modern government: the representation of the people, not as members of organizations, but individually. To quote a famous document:
>
> That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed [[source](http://www.ushistory.org/declaration/document/)]
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>
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**And we're missing a means of redressing wrongs, also known as "checks and balances" ... call it a *judiciary***
Nowhere in your described system does an individual have the ability to bring a complaint against the ruling council. Remember what I said about organizations basically reducing people to line items on a balance sheet? Judiciaries are, in a very generalized way, the means of ensuring that doesn't happen to the detriment of society. Somehow, you need a system that permits people to express the idea, "but that's not fair."1
**I could go on, but writing a book isn't what you need. They've already been written.**
You might be putting the cart ahead of the horse, which is a common behavior for young authors. You might have created your government before you created (or came to understand) your colony. A ruling council works well with a small organization, where the vast majority of people fit neatly into the organizations represented on the council. Those same people are all professionals, predisposed to work together to achieve a clearly stated goal.
But after you've added a bunch of babies to that mix, and those babies have become teens — *bored teens* — suddenly you have a bunch of people who don't fit the mold, and the "clearly stated goal" suddenly doesn't apply anymore becuase it isn't their goal. Nor will it be the goal for the bazillions of jobs that spring up to support a couple of generations of bored teenagers.
So, would your ruling council work? For a small enough colony, yes. For a large colony (frankly, anything bigger than 50,000 guaranteed), you need an actual government. To paraphrase another famous document, "that this [colony] shall have a new birth of freedom—and that government of the people, by the people, for the people, shall not perish." [[source](https://en.wikipedia.org/wiki/Gettysburg_Address)]
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1 *Perhaps the biggest reason judiciaries need to exist is because "fair" is always a wholly subjective word. Nothing is ever "fair." It's the judiciary's duty to find the balance between plaintiff and defendant that best suits individual rights vs. social needs. Remember, Satan's basic argument with Eve is that it wasn't fair she couldn't eat that dang apple... and look where we are now.*
[Answer]
There are a few problems with the setup you propose.
**Leaderless**
Unfortunately the structure you have set up is leaderless.
Not that all groups need leaders - like a working-groups to perform small tasks where everyone gets along, however when it comes to any organisation, or groups of people more than a few, especially complex government, leaders become important.
The function of leadership is multifaceted but essentially no work is done by the populace unless they are coordinated and organised. Governments today are complex systems, sometimes convoluted, yet their core purpose is to organise people - with for instance an arm such as an Executive. Without leadership it is easy to have:
* one part of government doing something contradicting another
* resource allocation problems (even 'fair' allocations may achieve little)
* rudderless, meandering government (no long term vision, no cause for people to work)
Although the above problems still occur in modern governments, image how often they will occur if there is no Executive to push an agenda. What you would probably find in your case is your military will be in defacto command, because that is what type of people they are.
**Overstructured**
Most governmental structures that are in place today (in modern day democratic nations) seem complex, but each element serves a functional role. In your case, the government is organised horizontally, almost like a class or caste system, instead of vertically in a check-and-balance oversight system.
History has shown that societies with large disparities in class don't function well. The artificial divisions in society prevent economic and political growth and end in revolutions, jostling for power or civil war. Instead:
* An Executive branch to give direction
* A Senate to check-and-balance the Executive
* A Judiciary to check-and-balance the Senate and the Executive
ensures the *responsibilities* of each part is established, not just *identifying departments* (as in your case).
**Civilian Command of the Military**
It has taken almost 4 millenia to get this right, but finally human society is dealing with the problem of the relationship between the military and civilians.
*The military must be a subset of civilian command, never equal to it.*
Most countries in the past (and present) have a constant problem with being overthrown or destabilised by its own military. A major tenant of international peace currently in the world is that decisions are political, diplomatic, economic or social, well before they are even on the radar of the military.
Your military should have no seats on your ruling council, they should be just *following your orders*.
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[Question]
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Imagine a world like [Pellucidar](https://en.wikipedia.org/wiki/Pellucidar) or [Skartaris](https://en.wikipedia.org/wiki/Skartaris). This world exists on the inside of a 'hollow Earth'. The laws of physics apply as normal, except as follows
* There is a gravitational force that attracts all objects to the interior surface of the sphere. This force falls off as an inverse square law until in the very center of the hollow sphere there is no gravity. Gravity can be expressed as $g = g\_o\left(r^2/a^2\right)$ where $g$ is gravity at a point, $g\_0$ is gravity at the 'surface' (9.8 m/s), $r$ is distance from the center, and $a$ is radius of the hollow world.
* The interior is entirely filled with breathable air. The air pressure is atmospheric (1 bar = 100 kPa) at the 'ground' level. Pressure may vary with gravity at height.
* In that very center, there is a light and heat creating point source of radiation. Unlike other hollow Earths, this one goes on and off, so there is both night and day.
The question is this: **What is the fastest way to get across the sphere in a balloon?**
The base answer would be just to travel along the surface of the sphere, but there are no internal combustion engines, so you would either have to 'sail' your way there, pedal your way there, or tether your balloon to a donkey and walk there.
Is it possible to take a short cut? Can you use the balloon's buoyancy and the decreasing gravity with height to take some sort of shortcut across the center of the sphere?
### Considerations
* The interior surface has the same surface area as the Earth.
* The light and heat felt from the 'sun' is the same as that felt at the equator on Earth. Feel free to work backwards to see how powerful the 'sun' has to be.
* Across the sphere means a point 180 degrees away (in all directions); all the way across the sphere.
* If you need to fly past or through the center, you can do it at night so as not to get burned.
* There are no breathing apparatus, so make sure you don't suffocate by piloting into a low air pressure zone, if any exist.
[Answer]
Let's consider a few issues.
* There would be no [atmospheric escape](https://en.wikipedia.org/wiki/Atmospheric_escape) into outer space. This isn't much to begin with, but with the atmosphere being completely trapped, you have more to work with.
* Next, The Earth's atmosphere is about 300 miles thick on the outside of a sphere. A sphere's volume is 4/3 pi\*r3 The earth's radius is 6.37x106 meters for a volume of 1.08x1021 cubic meters. Add 300 miles (482,803 meters) and you get 1.35x1021 cubic meters for a atmospheric volume of 270x1018. If we process all that math to get the inner atmospheric thickness we get 359 miles.
* Now, I've ignored the fact that the atmosphere thins as altitude increases, but this actually works in our favor as the thickness would be more then 359 miles due to the compression of density near the surface. Adding the effect of no atmospheric escape, and using an itch on my right elbow as my guide, I'm going to boldy declare that the thickness of your atmosphere is approximately 400 miles.
* Finally, I'm going to note that, simplistically, the difference between having a sun that illuminates the entire world during the day and a sun that only illuminates half the world at any one time is that while on Earth you get winds, on your world you'll get a daily increase of barometric pressure and a nightly decrease. This will also have the effect of increasing the atmosphere thickness, which will reach its peak in the mid-afternoon. (I'm ignoring everything like seasonal conditions such as your sun switching on for longer periods during the "summer" and shorter periods during the "winter." Just one season for my answer, thanks!). How much the barometric pressure will increase (and therefore the atmospheric thickness) depends on how much the atmosphere heats and how much ocean you have to evaporate water into the air. But, I'm being outrageous, so let's claim that gets us to 450 miles of thickness at 3:00pm.
OK, you're trying to get to the diametric opposite of where you began. As Pojo-Guy points out, bouyancy will only get you so much altitude, but rather than worry about what kind of gas you're using and the weight of your dirigible, I'm going to estimate a best-case scenario.
As the crow flies, if a crow didn't need to breathe and its feathers were entirely heat resistant, we're talking about an 8,000 mile trip. But you can't reach an altitude of 4,000 miles.
What you can do is float straight up 450 miles in the afternoon, then proceed in a sinusoidal path (400 miles to 450 miles altitude depending on what time of day it is) until you're over your landing point, then you pull the rope and drop like a rock.
Thus, your fastest time would be the time needed to rise 425 miles (on average), (Tascend)) + the time needed to fall 425 miles (on average), (Tdescend) + the time to traverse the surface of a sphere 425 miles (on average) less than the surface the cows are standing on (and I'm assuming it's flat rather than worrying about whether or not we're starting/ending in a valley or on a mountain) (Tsphere), which is pi\*r miles or 11,231 miles.
So...
* You need to rise 425 miles.
* You need to fall 425 miles.
* You need to cross 11,231 miles.
If we assume the cruising speed of the [Hindenburg](http://www.airships.net/hindenburg/size-speed/), 76mph, and half that to ascend/descend, then it will take 22.37 hours to rise and fall, and 147.8 hours in transit for a hair over 7 days to make the entire trip.
*Unless there's weather... Remember that nightly decrease in barometric pressure? Yup, rain. Lots of rain. Maybe even hail... the weather on your world will be interesting... and you'd hate one of those Far Side moments when your brother shuffles up next to you and touches your skin with a small hydrogen leak nearby....*
And, lest we forget, you can't actually get that high. So the trip is probably a whole lot closer to 2 weeks.
**You'll notice I'm using a dirigible, not a balloon. I'm not convinced you'll have significant winds in your hollow world. There's nothing pushing the air independent of the spin of the world other than the comparatively gentle push of evaporating and condensing water vapor. Methinks a balloon would be a curiosity as it can only ascend and descend, but not travel.**
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[Question]
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This concerns a habitable, earthlike moon orbiting a gas giant, which is not tidal locked, and has an elliptical orbit eccentric enough to avoid frequent deep winter freezes (the freezes do happen, but they are more like once a decade). The tidal range is higher than Earth's; I'm going to ballpark about 30m/100ft for the relevant area. I'm sorry for not showing numbers--I know I will have to fudge them a bit regardless to have this setup, and I'm not sure how useful they will be here (plus astronomy & physics is not my strong suit). I can try to write some up if specific numbers would be helpful. Anyway, on this world there's a non-spacefaring people living on a very difficult-to-reach island, and that island is what this question really is about.
They know of continental land to their north, but in other directions they know nothing of and they're not super into finding out (i.e. it doesn't really matter what's over there, so if you think there should be land formations then there will be). Around 8 centuries ago another cultural group from the mainland was pushed out and made their way across the sea to this island *somehow*. It's surrounded by steep cliffs and is only accessible during high tide in most locations. The native population has been living here for a very long time, at least a couple millenia. It's not a new island. The first question I have is: **is it more likely that it is a volcanic island or a peninsula which was cut off from the mainland to the north by rising sea level/erosion?** Which of these two options would be better if I wanted the island to, you know, not quickly erode into nothing by punishing tides, but also have the "wall" appearance of the cliffs, sort of like [these](https://cdn.tucantravel.com/images/joomgallery/originals/large_385/thailand_159/thailand_beach_20161111_1398795226.jpg) (Thailand) or [these](http://bayoffundytourism.com/wp-content/uploads/2013/05/cape-split.jpg) (Bay of Fundy)? Are these sorts of monolith type rock structures even possible with very high tides? What would be the most likely composition of these cliffs?
Ideally, I'd want very occasional large tides which rise up to the top of the cliffs, but usually never rises more than halfway, making it completely inaccessible by boat most of the time; I think this is possible because of the moon's elliptical orbit, and/or maybe with help from another moon whose orbit coincides with this one's every so often. Is this a plausible setup?
[Answer]
If I understand your question correctly, we're talking about an island quite distant from the shores of the mainland which has been reached by a seafaring civilization. This island is only accessible at high tide because the rest of the time the island is separated by steep cliffs from normal water level.
## This sounds like a volcanic island.
Volcanic islands pop up essentially wherever they want, as long as a mantle plume can form underneath it. This gives you a lot more freedom with the actual distance from mainland to island.
If it's a part of the continent it's just a continental island. This requires the island to be part of the same tectonic plate as the continent and to be physically connected underneath the ocean. Both of these considerations limit how far continental islands are normally found from the continent itself.
Volcanic islands can indeed have steep sides, which is one of the reasons [Mehetia](https://en.wikipedia.org/wiki/Mehetia) remains uninhabited- it's nearly impossible to land on. Continental islands often have steep cliffs due to constant wave action and uplift, but as you point out, that's likely to erode away completely over millenia.
I'd also like to argue that tides themselves are not especially erosive forces. The water in a tide moves very slowly vertically, which makes it bad at removing rock from islands. Wind waves are the biggest erosive forces in the ocean, and I'd recommend focusing more on those to reshape surfaces than the large tides.
## Scenario:
This planet undergoes intense Milankovitch cycles. It has long cold periods where much of the water is locked up in ice, followed by long periods during which much of the water is in the sea. During one of these interglacial periods, a new island forms and breaks through the surface. Corals grow and flourish, forming an barrier reef and lagoon. During this time, exploration is rampant from the seafaring community on the northern continent.
Over time, erosion from winds and waves removes the pointy top, leaving a guyot, and the lagoon is filled with the sediment, leaving the steep sides of the atoll. The island is colonized and settled for its fresh, fertile soils and lack of native fauna. As the Milankovitch cycle turns (rapidly, due to positive feedbacks), ice is locked up in the poles and the sealevel drops ~30 meters. Now, the colony on the island is trapped at the top of their guyot (quite happily, with plenty of food and no native predators) by the steep coral walls that now appear as cliffs. However, when the sun and moon align just right, the water rises just close enough to be accessible. This is when your story happens!
[Answer]
The thing about having it be a cutoff peninsula is that will make it not all that remote from the rest of the uncutoff peninsula. But you can have a mountain range that continues along underwater, with some mountains being high enough to be islands in their own right. The [Andaman Islands](https://en.wikipedia.org/wiki/Andaman_Islands) are like this, and these are considered remote, with the natives having lived there for thousands (tens of thousands?) of years with little or no contact with outsiders. But they are only 879 km from Bangkok.
In contrast Hawaii is 4000 km from San Diego. Probably the same difference if you are in a stone age boat or a lizard floating on a log, but if you want to really be remote, you need a volcano to make land in the middle of deep ocean. Basaltic lava of the Hawaiian type will make you some beautiful steep cliffs. These are on the Big Island.
<https://lovingthebigisland.files.wordpress.com/2009/10/0-pololu-cliffs_edited-14.jpg>
[](https://i.stack.imgur.com/w1sJl.jpg)
Tides are the hardest part of your question. I do not understand why tides are not uniform across the Earth; subsurface features are invoked but I take away that this is not something amenable to 180 seconds of superficial Googling.
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[Question]
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I am trying to figure out how to build a human colony on a moon (75% of Earth size) of a gas giant.
Some details of the planetary system chosen for colonisation:
* K-type main sequence star (about 60% of Sun size; orange; lower radiation emission than Sun);
* large asteroid belt which can be mined for all and any necessary materials;
* a gas giant is in the Goldilocks zone (closer to the star than in our Solar system);
* this gas giant does not have a strong magnetosphere;
* it has 3 moons, the largest of which is being colonised;
* this moon is the only candidate in the entire star system for establishing a colony.
The colonists do not have contact with Earth and cannot receive supplies or technology updates. The majority of them are scientists (not just STEM, social sciences as well) and engineers. The team is very small — under 200 people.
Their genetic engineering technologies are higher level than today, but not at the level of magic. For example:
* Corrective genetic therapies that modify all cells over a relatively short time are available, but their effectiveness is limited to fixing/changing small chunks of DNA. Changes in adult organisms at chromosomal level and massive tissue transformations (like a sex change) are not possible.
* Utilization of techniques like CRISPr allow permanent inheritable genetic changes even when a therapy is administered to adults (not sure about women, but males definitely).
* "Designer-babies" are not only possible but the technology will be widely used to avoid population bottleneck and Founders effect.
* Decoded genomes of various species are readily available in a digital form and can be synthesised in a lab.
* The overall understanding of human genome (what genes and their groups are responsible for) is much higher than today's but is not 100%. Thus it is not possible to create a race of highly intelligent super-human beings with a precise set of characteristics.
The colonists do not have moral or ethical restrictions on experiments. But they would like to avoid creating human chimaeras as much as possible. Their main objective is to ensure the survival of the colony while still keeping it human.
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There are some radiation resistant species on Earth, notably [Deinococcus radiodurans](https://www.wikiwand.com/en/Deinococcus_radiodurans) and [Thermococcus gammatolerans](https://www.wikiwand.com/en/Thermococcus_gammatolerans). Both microorganisms can repair DNA damage even after receiving very high acute radiation doses. Theoretically, we can use their genome to figure out what genes are responsible for radiation resistance and then modify genomes of all other species (humans, flora, fauna, etc.). Perhaps the first generation of colonists will not be able to undergo such a drastic transformation and will be confined to the radiation shelters. But all the following generations and ecosystem will be protected.
I wonder if this is a feasible strategy. Are there any other considerations that I have to keep in mind (for example, the moon's atmosphere deteriorating at a rate higher than robotic asteroid miners can replenish it)?
[Answer]
Here is the thing: Human cells and DNA already have a lot of DNA repair mechanisms. The main reason why those bacteria are so much better at it then our cells is because they're so simple and uncomplicated compared to us. Unfortunately these big differences mean that whatever nifty mechanism the Bacteria uses just won't work in Human cells. You're better off making your scientists design a completely new human-specific defence mechanism and edit that in instead.
[Answer]
If at all available such a DNA-preserving technology would be invaluable for tons of usages, including, but not limited to:
* Cancer prevention.
* Retrovirus containment (AIDS)
* Antiaging.
Main difficulty is such methods are deeply ingrained in cellular metabolism; it is unclear what *other* effect they would have on overall building of complex organism as we are.
Please note we have *much* less genes than phenotypic characteristics (by orders of magnitude), this means a single gene has effects on *many* areas (this is different, e.g. in arthropods); it is **not** possible to change a single trait in a complex vertebrate.
[Answer]
I think engineering from bacteria wouldn't be our first approach.
I think we'd try to enhance or own DNA repair mechanisms before engineering in new mechanisms, from bacteria to boot. I forget if D. radiodurans (etc) is radiation resistant because of DNA repair or because of some novel feature of its cell wall - Being able to sporulate, for example. Look into that. If they are resistant because they make a special cell coat, that would definitely not work in humans.
We humans can repair radiation damage to some extent. Think about people who are more susceptible to UV damage (Xeroderma pigmentosum). They are less good at innate repair mechanisms.
If I lived in your colony I'd suggest to my colleagues that we genetically amplify our innate ability to repair DNA (and other radiation damage) rather than introduce bacterial genes.
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[Question]
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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.
It is estimated that in about five billion years, our sun will enter its red giant stage. During that phase it will expand and completely engulf Mercury, Venus and possible Earth. Earth will either be destroyed or become uninhabitable.
Will there be a phase during this development where the sun's energy at the distance of Jupiter becomes strong enough to turn the surface of Europa into a liquid ocean but not yet strong enough to completely evaporate it? When that happens would Europa be habitable for humans and if yes for how long?
[Answer]
I am assuming that by 'habitable' you mean 'in the Circumstellar Habitable Zone of the star,' (aka Green Zone) since that is what is going to change when the sun turns into a Red Giant.
Sol's current CHZ is estimated to range between 0.5AU and 3.0 AU. This wide band is dependent on a lot of things. Earth-like planets can function in the nearer reaches of this, while greenhouse-planets can potentially sustain life further out. ([ref](https://en.wikipedia.org/wiki/Circumstellar_habitable_zone#Solar_System_estimates))
According to the write up "Can Life develop in the expanded habitable zones around Red Giant Stars?" ([ref](http://arxiv.org/abs/astro-ph/0503520)) They provided a new estimate that says that when Sol enters the Red Giant phase, its new CHZ will range from between 9AU to 22AU. Jupiter is situated an average of 5.2 AU from the sun. This positions it too close to the sun to be within the green band, all the water on Europa would boil off. So no, Europa would not be habitable...too close to the sun.
On the other hand, Saturn orbits the sun at an average distance of 9.6 AU, which plants it firmly in the 'close-range' green band of the new CHZ, which is where Earth-like planets may exist. Titan, one of Saturn's moons, is presently wreathed in an atmosphere of hydrocarbons and has a methane cycle analogous to Earth's water cycle...however, the planet itself is composed of a significant amount of water ice. It would take a lot of work to clean the place up, but once the sun turned into a Red Giant, Titan would be a potential terraforming candidate...if you could get its methane levels under control and stabilize the atmosphere into something humans could breathe.
Do note that this does not mean Titan would be habitable by humans on its own...just that it would be the right temperature for humans to potentially live on. As it is, Titan's atmosphere is not friendly to human lungs, even if it wasn't ludicrously cold. We would have to terraform it first.
The sun would stay in its Red Giant phase for about one Gigayear (a billion years)...so that's how long you'd have to live on Titan.
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It is medieval times, and mythical creatures aren't so mythical. About half of all mountain lions are griffins, which use their wings to glide over rough terrain. Dragons dwell on mountain peaks, or in deep caves. (There are sea serpents,but they are very rare, so they don't really matter). And thunderbirds ride in on oncoming storms.
Dragons feed off of pretty much anything, and they range far and wide. Their body is anywhere from the size of a komodo dragon to a buffalo (not counting their tails and wings).
My previous [question about thunderbirds](https://worldbuilding.stackexchange.com/questions/34980/if-thunderbirds-were-real-how-would-it-affect-shepherds-and-ranchers).
My previous [question about griffins](https://worldbuilding.stackexchange.com/questions/35095/if-mountain-lions-were-griffins-how-would-it-affect-other-animals).
[](https://i.stack.imgur.com/FVp8B.jpg)
Note - The areas that are shaded are not part of any country for a variety of reasons. Travel through the shaded swamp is impossible. The outlined areas are the different countries. The entire map is about the size of North America, and I haven't gotten around to cities yet. (Forgive the messiness of the shading and lines, I did it on my iPad.)
Given that these creatures exist in a medieval setting, how would trade between the countries above be affected?
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Well, if they had tame dragons they could speed up travel so increase trade speed and make much quicker cross ocean travel. Otherwise I can't see how trade would be affected. The human traders would travel in large groups and some would probably be armed in dangerous areas such as mountains anyway in case of bandits or mountain lions. These groups would be large enough to scare off or drive off griffins. The traders wouldn't be stupid enough to travel through storms and if they did go through a storm the weather would be more dangerous than thunderbirds.The dragons would be the only threat and trade routes would go around areas they live/hunt in although if these are mountain peaks people wouldn't cross it anyway but would go around..
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**Trade would be the same as through any wild lands.**
Trade caravans would include a contingent of guards that are trained to deal (or gained experience dealing) with the local fauna. The creatures would likely learn to avoid humans after a few encounters. As the humans advance and build kingdoms then hunting parties would likely be paid to clear out dangerous creatures and open additional trading routes.
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I don't see trade been affected been affected that much. In our world stories of monsters abounded. Locations were monsters are believed to live or hunt were marked on maps ( here be dragons). People Crossing long stretches of territory would avoid these areas. In your world the same thing happens only the monsters are real.
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As people would already be aware of the creatures, they would pretty much be aware and also, would have designed tech or strategies for dealing (and/or) combating with them too.
For example, dragons exist in the Harry Potter world, and they are portrayed as dangerous as they are, in most other classics and mythological works. However, the people there have learnt to tame them, and some, in fact, learnt to use them for regular purposes. For example, the owls and birds for mail, etc.
So, they wouldn't affect trade as much as we would expect. These would be my reasons why:
* As cited in the Harry Potter example, people would know how to tame them. In fact, people might also use them to help with trading. More like security. What's more powerful than having a dragon standing as security for your trade ship (if he's trained enough not to set the ship on fire, of course)
* If they can't be trained, then **people would definitely design trade routes which are less vulnerable to attacks from the wild beasts**
* **Design security/weapons which help them secure the trade routes from the beasts**. More like border security check posts
Having said that, I would still argue that people would be able to tame them, and in fact, train them to make trade easier and faster.
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My moon is the basis for a fantasy setting, but I just can't bring myself to abandon science and say "a wizard did it." I want to make the months and seasons realistic, and I want to find a way to make this, or something like this, work. I'm hopeless in math, so I'd like to enlist some help here.
The gas giant probably needs to be larger than Jupiter because its planet is approximately the size of earth. It orbits twin suns in a binary system (the suns circle a mutual center of gravity). I want my moon's day/night cycle on the habitable moon to be six months, meaning a "day and a night" are the same thing as a "year." It's kind of important for the cultures I'm creating.
I'd prefer a way for both sides of the moon to get some sun. I'm also aware that eclipses are inevitable.
So here are my questions:
* How long should the orbital period of the moon be, how far away, and how much would it dominate the sky?
* Axial tilt?
* What would the sky look like throughout the seasons, and what might the seasons be?
* Can I use atmospheric pressure and high winds to equalize the (obviously extreme) temperature differences?
* How might my habitable moon be affected by the rings and other (much, much smaller) moons of this gas giant?
* Is there any way to limit (though not stop entirely) the vulcanism that would doubtlessly plague a moon like this?
* Can I build a remotely earthlike planet – in terms of climate – in a scenario like this, even taking into account the above mentioned temperature differences?
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I don't think that this setup will allow for a binary day/night cycle, no matter what rotations you use. I'd love for someone to prove me wrong but I think that having two stars just makes the day/night cycle too complex.
Consider the following:
If the gas giant orbits both stars, then at some point it will lie directly between the two stars.
If the moon makes one orbit around the gas giant in this time it's going to have two major states: one where it is illuminated by both stars and only a tiny sliver of the moon is in 'night' and one where one half of the moon is illuminated and the other half is in night, having been occluded by the body of the planet. No matter what rotation you give the moon this leads to there being a distinct difference between the length of the day in one state and the length of the day in the other.
Then you can assume that at some point the planet is going to be on the 'outside' of the two stars, and will only be able to 'see' one star.
At this point the moon has two major states: Total darkness, or half of the moon illuminated. It alters between these states with a period equal to its orbit around the planet, and no matter the rotation of the moon for at least a portion of it's orbit it's going to be night all over.
All of the above assumes that everything is orbiting in the same plane and in a non-eccentric orbit, because it gets even worse if you throw in inclination and eccentricity as you then have to worry about day/night cycles at different latitudes of the moon (and the planet).
All things considered: This is a situation where it's acceptable to not even try justify how your world works, and just say that it happens. Maybe throw in a tactical dust cloud that obscures the stars at a critical point?
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your question maybe would take better place at the astronomy-section of stackexchange... or maybe not.
Anyway, while math is my enemy too, I came across such questions while programming a tool for astronomy purposes.
**The System**
First of... design a stable binary system, before you place your living beeings. There are many out there in space in reality, so its plausible to assume these can hold planets with lifeforms too.
But one point creates headache at my side: you want your moons planet orbit both suns. He would orbit the... uh, what was this name... barycenter (?) of these suns in that case, getting pushed around by one of the two suns on a regular base... hell, I don't want to this planet, when it and his two central bodys form a conjunction. Here the math kicks in, and I have to fall back to speculate, that it might rip apart a big gas giant if he needs to be close enough to be inside the habitable zone of this system.
But! Most binary and trinary systems don't have their suns do a close dance around each other. Prove me wrong, but I think in most cases the second sun acts as a remote planet, that happens to do stellar nucleosynthesis. So the second sun orbits the central sun faaar away - think about the oorthian cloud, or what is name was - and have to use what was left of material when the first sun collected itself. So it might be a red dwarf.
Another thing - two real close dancer suns will eat each others material - the bigger one can steal stuff from the smaller one, if close enough. That might result in a pretty spontaneous combustion of the small one. But to make this work, the big one need to be pretty big (H or O class? Hmmmm... no, any class super or hyper giant may be sufficient). At least the "bright" ones tend to have pretty short lives... short enough, to go supernovae and destroy their small follow star before any life could develop.
Well, I would recommend a decent stable system, where star number two is a far orbiter. Feel free to update my knowledge about this if I recalled this wrong.
**The Planet**
Big gas giant, even bigger than Jupiter? Don't go to far... let me kick my brain... but I think over 1\*10^28kg of mass this thing will fuse some low level nuclearsynthesis. Other words: you might get a brown dwarf. They consume a special element I can't remember (something containing a y?), don't do what real stars do but would be much warmer than a common gas giant.
Even a Jupiter size gas giant will be a bad place to orbit around. Ever heard of jupiters music? Feel free to google this :) But anyway, jupiter size gas giants may be pretty ray bursters. This may encourage evolution, but wouldn't be a pleasureful place to life for human like creatures. Okay, I may overestimate the power of the emitted rays, but that something you might think about.
A planet this big will catch most stuff in its orbit. I think astronomers call this "clean its orbit". Due to many millenias every piece that came across the gas giant will be slung away. It can go away, it can become a new satellite, or it may impact your moon. When life there did grow naturally, most of these planet killing stones should have gone... but maybe not all.
Oh, same count for your moon. It will clean its path, so if its an earth-like stone planet, you probably won't have any rings at this gas giant.
**The moon**
Ehm... well... you know... to get a orbital period of one earth year for a planet (moon) about the same size (and mass!) as our beloved earth, you need a earth-like orbit.
So... about 150.000.000 Kilometers. If you have a sun-like star AND your gas giant inside the habitable zone, this would get... warm in summer. Very warm. Well, you moon-earth would slam inside the central sun or get catched by it in a mercury like orbit.
Hm... one point I'm not sure about right now is... how much closer to its central body a satellite may come when taking the central bodys mass into account. I think you won't need the whole 150.000.000km, but... hm... 15 Million maybe. Argh, I have no access to my program here, but I think someone who can calculate this will pop up in this thread pretty soon :) Or use one of the free calculators in the internet... but to make a bet: to have an orbital period of one year for a planet of a earth like mass in 15 million kilometers semimajor axis, you would need a central body of 1/100 sun masses... that is... a brown dwarf? *sigh* there is a reason I need a program to guess stuff like this. whats 1.9 x 10^30 / 100 ? 1.9 x 10^28? well, that would be pretty brown dwarf, wouldn't it?
But! but, but but... You want a bound rotation of your moon. That means your moon needs to be close to you gas giant. close enough, that the gravity of the gas giant can friction break your moons rotation using waves, air and even continental plates. So... this close, you will receive lovely amounts of hard em rays and get a forced orbital period of... some weeks in best.
But you say "lol its magnet field would neutralize this noob"? But we need to take care of the seismic activity and vulcanism, which requires a moon with death core.
Correction: a earth size planet is likely to have a liquid core very long. Even Mars and Venus should have one, Mercury... don't know. Hell, didn't the biggest of Jupiters moons claim a magnet field?
It looks like all your creatures can do is embrace the natural disasters. But anyway, once rotation got bound, things will calm don I think.
How to neutralize the temperature? Okay, I'm off here. If you don't want to get your moon scorched by the central sun, it should be at the outer range of the habitable zone. But... here a brown dwarf would be useful, because it does emit heat I think. So the side bound to the gas giant / brown dwarf may receive enough energy to allow liquid water, while the other side... you may install a ice princess over there.
To expect what the seasons be like, I would like to wait for what moon - planet - binary sun constellation you vote at the end. Because it will matter a lot.
To answer you last question... maybe. If you can accumulate enough energy from what sources available to get about the same level as we do have on earth, it may work. Get this energy from a sun, or two, a brown dwarf, an active gas giant... but don't get too much, or you get a Venus, and too less will create you a Mars.
Then avoid heavy hard rays, so no blue or white central star and a peaceful gas giant. To avoid heavy changes of temperature and climate, you need to stick in a narrow piece of your habitable zone, so no wide orbits around that gas giant (needed for bound rotation too), which means you have to forfeit the six month day/night I'm afraid of.
But you can give your gas giant a slight elliptical orbit, so it will bring its moon closer to the sun half of its year, which may be... well, I didn't talk about this, but if your gas giant wants to be stable, you may need orbit him in a distance that take many years for a single circuit. That would make a maya-civilization happy, because their calendar would work pretty well telling when the next "summer" will arrive.
So. I'm out of words for now. And interested in your decision about this system at the end.
Have a nice day
Edit: Oh well, that answer in that first comment to your questions is 10^28 times better than my stuff... :( keep with that
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It's well known that Mars has a very weak atmosphere as a result of billions of years of solar wind bombardment. Mars lacks a sufficiently large magnetic core to generate a magnetosphere strong enough to block the solar wind.
My civilization has found ways to generate enormous magnetic fields (without breaking the laws of physics) and they want Mars to have an Earth like atmosphere, eventually. They know they need to solve the magnetosphere problem first or any atmosphere they add will be wasted effort.
*How much energy will it take to generate an Earth equivalent magnetosphere for Mars using technological means?* Altering Mars' crust and core isn't an option for solving this problem.
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Shamelessly taking numbers from [this answer](https://physics.stackexchange.com/a/139762) the Physics SE had such foresight to provide a year ahead of time...
You would need to provide $1.5 \* 10^{22} \text{ W}$ of power with a current of $1.6 \text{ GA}$ to replicate the Earth's magnetic field, given a $1 \text{ cm}$ cross-section of copper wire as the generator.
See the linked answer for the full derivation and extended discussion.
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There are well-known procedures for tricking human brains into assigning 3-dimensional perspective to 2D images. Some, like 3D glasses in a theater, work without effort, while others, like the stereogram of a galloping horse below, require some training and many people cannot do it at all:
[](https://i.stack.imgur.com/U6GUx.jpg)
We have a good mathematical understanding of 4D, and we routinely use computers to handle calculations in n-dimensional spaces. The problem is that our brain is adapted to create a 3D pseudo-emulation. If you think about it, it's created by neurons spiking: nothing intrinsically 3D about it, rather us Earth-mammals adapted to use 3D because it's useful in a 3D environment.
Now I want to be in a place where a human girl, aged about 12, is able to "see" in 4D. More specifically, I want her to achieve 4D perspective on a 3D object. Assume that a device exists to grant that information to her if she can understand it. It may require effort, like the stereogram, work for a limited 'volume', and she may only be able to sustain it for a brief time (or it may come as natural as breathing).
I know of no human who claims to be able to do this, so this poses a bit of a problem. While it may come down to the wiring of our brain, I'm trying to think of a training program (for the child or even for the infant she once was if we want to take advantage of extra [neuroplasticity](https://en.wikipedia.org/wiki/Neuroplasticity) of newborns) that would engender and boost this ability. I'm thinking computer simulations, minor brain surgery, etc.
**How could we train/modify people to see in 4D?**
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It is fairly easy to depict 4D objects. A variety of possibilities exist, but probably the most intuitive is to use colours. For instance, map the 4th dimensional position of the object to frequencies of light. A purely 3d object is then monochromatic in this view, every element of it occupies exactly one frequency of the spectrum.
A 4-flat object that is shifted along the 4th dimension would be simply a different colour, and so free to coincide with the other object in the same 3d location. Meanwhile an object with depth in the 4th dimension would occupy a range of frequencies and so be a mixture of colours.
What this does not do is make 4D intuitive, which you didn't mention but I suspect is your real objective. Even stereograms do not do this for 3d. All you are doing there is sending visual input that duplicates, to some extent, the visual input the eyes give on a 3d object, fooling the sophisticated built in spatial recognition parts of the brain. 4D spatial recognition parts of the brain simply do not exist. (Try and mentally rotate an arbitrary 3d object and it's easy in arbitrary rotations. Try it for a 4D object and uhhhh) To make them exist, I imagine you probably have to intervene drastically in the early development of the brain, or have some way of doing some serious rewiring....
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If you want to develop a 4D optical sense, you surely need some kind of advanced optical input, that is, an interface to your visual nerve, and a way to train it. Kids usually do that training by cross correlating the optical input with that from the nerves on their hands, I assume. ;)
I guess you are right that a 4D brain is not necessary, although a 3D brain surely will hit its limits with, say, a fifth or sixth spatial dimension.
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I was looking a bit at the evolution of Stars and one thing I sometimes see floated is this idea that in the far flung future, when the sun has ballooned into a red giant and the earth burned to a crisp, the solar system's habitable zone has moved far out enough that Saturn's moon Titan has become a pretty nice place to live.
There are some books that work with this idea, having some sort of weird alien species develop on titan long after all life has been extinguished from Earth. [Stephen Baxter's](http://en.wikipedia.org/wiki/Titan_(Baxter_novel)) book on Titan is a good example.
What I want to know is whether or not a Red giant could be counted upon to provide a suitable habitable zone. Now I understand that Red giants are not long lived, so we'd probably only be looking at around 1 billion-1.5 billion years max that it would maintain itself before giving up the ghost. Can it sustain a stable Habitable zone over that time? I understand that there are stages where it will inflate and deflate in size and ones where it will blast off huge amounts of matter which I assume would send things screwy and would probably sterilize a world before anything interesting happened, but could there be a sweet spot of about a billion years of relative stability when looking at a Red giant formed from a star about sun size or smaller?
I'm imagining some sort of world in the outer solar system that may develop life up to maybe a Eukaryotic stage (being generous here) in a subsurface Ocean before its star puffs out and a habitable zone expands to where it is, allowing liquid water and atmosphere to exist on the surface. At this point might it be conceivable for photosynthesis to emerge, oxygenation of the atmosphere, Multicellular life of increasing complexity, maybe culminating in an intelligent race before the clock runs out? Is this conceivable with a red Giant, would life emerging billions of years before mean that they would be ahead of the curve of some the developments on earth, and would a red Giant possibly be able to offer stable enough conditions over a long enough period for complex life to evolve?
Thanks!
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It's not a common statement, but **a billion years isn't long enough.**
If Earth is any example --actually it's our *only* example-- getting from habitable to single celled takes about half of a billion years on its own. Getting from single cells to multicellular took another three billion years.
We've spent three and a half billion years, way over your sun-keeps-ghost-budget, and all we have to show are sponges and fungus.
For the case of Titan, it would be better to start with some microbial contamination on [Huygens](https://en.wikipedia.org/wiki/Huygens_(spacecraft)), or future Titan lander, and go from there. Then we get to skip all that tedium of the first few billion years straight to the far more interesting last billion years. Things could get interesting right after the moon becomes habitable and feasibly, though unlikely, they might get to the point where they decide *not* to let the Star Wars prequels be made.
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***YES***
To elaborate on @Samuel 's very fine answer, stars of all but the smallest constant luminosities will have inhabitable zones.
**What will the Sun's Luminosity be?**
Our Sun's luminosity is expected to increase up to around [5000x current levels](http://en.wikipedia.org/wiki/Sun#After_core_hydrogen_exhaustion).
**Where will the new inhabitable zone be?**
Since solar irradiation depends linearly upon luminosity and by the $ \frac {1}{r^2} $ of the orbit, that means the inhabitable zone of Red Giant Sun will be:
$$ r = \sqrt {5000} = 70 AU $$
and if you assume the inhabitable zone is +/- 20% of the median distance, this gives you a range of 56 - 84 AU for habitable bodies.
**What sort of bodies orbit are out there?**
This is beyond the orbital radius of any planet and is in fact beyond the [50 AU limit of the Kuiper Belt](http://en.wikipedia.org/wiki/Kuiper_belt).
There are probably some stray planetoids out there and perhaps there is something as large as Earth but we've not detected anything like that yet.
**Other issues:**
As @Samuel pointed out, a billion years simply isn't enough time for evolution to develop anything interesting from scratch.
But if we looked at this as a colony world of Earth settled by post-Earth humans, we could definitely have transplanted a biosphere there. If we did that, there would be enough time for interesting things to happen from our starter culture.
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The big problem (or advantage) is that red giant light spectrum is shifted to infra-red and micro-waves. It would be way less ultra-violet light. So considering the habitable zone the one that will receive around the same power/surface area, it would be more heating light than ionizing light. I would guess the life forms would have to adapt to this condition. For example current live beings wouldn't be able to produce vitamin D. But the production of ozone would also be reduced and since the ozone filter the UV light things could balance out a bit.
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It seems that most of the technological development of humanity is dependent on our ability to form a society. The sharing of ideas and building on the discoveries of others is how we have advanced. If an intelligent creature on another world tended not to associate with others of the same species, could that species have technological advancement beyond fairly simple tools?
I would think that a solitary creature, that only interacts with others for mating purposes, would not. I think that there would need to be some amount of communication for such a thing to be possible. However, there are many different degrees of sociality. How much socialization is necessary? Is caring for young until maturity enough? Or dwelling exclusively in family groups?
How would technology develop in less-social populations, and is there a limit to how much advancement is possible for them?
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I'll go from an evolutionary standpoint...short answer is quite a bit of a social nature is required for intelligence to arise in a species let alone technology.
Our intelligence felt a few selective pressures to increase...not simply on an individual level, but on the species level. Quite simply put, my survival is more-so dependent on others intelligence than it is on my own. If you are watching my back and I'm watching yours, then 'your back' and it's preservation per-se is dependent on my intelligence and ability to recognize danger...your only influence on this was choosing me to watch your back in the first place
Non-social intelligence doesn't have this pressure on it. Yes, the individual creature becoming more intelligent helps it, but the species gaining intelligence actually comes at the individuals detriment. If you and I are competing for food, living space, mates, etc...the less intelligent you are, the better off I am (possibly). As such, the selective pressure on intelligence for the entire species just isn't there.
So there's my tipping point...when the socialness of the species reaches a point where each individual is dependent on each other for survival more than an individual relies on itself for survival, then you will see a population that can begin on the technological development path.
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The challenge of building up any technology is that scientific knowledge is a cumulative thing. Today's scientists stand on the shoulders of yesterday's scientists, relying on earlier discoveries to provide the building blocks for new experiments which in turn lead to new discoveries.
In the absence of society, another method of information preservation and transferal will be required to facilitate the accumulation of knowledge.
A racial memory could serve this purpose, allowing the child of two scientists to be born with complete understanding of their parents' disciplines. This child could then work in isolation on advancing his parents' discoveries until rather late in her career, she meets and mates with an equally qualified child of two other scientists. The grandchildren which they create would be born masters of four disciplines and their great-great-great-grandchild might just know everything :^).
But if that g-g-g-grandchild died before bearing a child of their own, all that knowledge would be lost until some other child with an amazing pedigree came along and rediscovered it.
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It is said that dogs might be able to smell in color. Imagine taking these ability to the next level, where you're scents can tell entire rich story, and entire book in a chemical message.
Now take that and apply it to territorial animal, like a quasi-society of wise bears. While they don't love each others company, they'll leave these complexe messages on their borders, for their neighbors to read.
This philosophical bears could learn a lot about each other and the world by "reading" these books. Eventually, you're bears will have to learn to work together, to build stuff that no one bear alone can build. Perhaps they can specialize, with smith bears and weaver bears and potter bear and beekeeper bear (lots of those around), fisher bear and so on.
Some tasks will geniunely require many bears in the same place, but perhaps they can learn to tolerate each other for short periods, no?
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To eliminate the requirement of communication, you can eliminate the need for communication. [My favorite planet](https://worldbuilding.stackexchange.com/questions/2655/living-planet-possible/2803#2803) - living ocean which inhabits the whole planet as single organism.
I am afraid that other than that, better society will result in better knowledge production and sharing, and faster technological progress.
It is entirely plausible that **language (and community) is what enabled civilization, and was crucially important even before technology**: such a weak animal (with weak teeth, little claws, no strong armor) was able to survive only in teams/tribes, and even hunt big animals to extinction - except in Africa, where such animals co-evolved.
So even maybe community might not be crucial when you have technology (all these mad scientists), but is IS crucial to get to the stage when you can start developing technology.
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According to [this](http://www.reddit.com/r/askscience/comments/2d54bn/why_do_the_rings_around_a_planet_only_form_on_one/) Reddit conversation, the detritus around a planet tends to form into a single plane located around the equator given enough time. How long does this process take? Suppose a planet had a multitude of moons at varying orbital heights not on a singular plane. Could these moons retain their non-equatorial orbits and, if so, could they influence planetary detritus in such a way to form rings in more than one planar space?
For extra credit, provide a look at how the multi-planar rings would look from the planet's surface and how that view might impact human society.
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> How long does this process take?
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We don't know. As I discussed [here](https://astronomy.stackexchange.com/questions/8616/recent-origin-of-saturns-rings/8617#8617)1, Saturn's rings could have formed billions of years ago or only a few hundred million years ago. [Wikipedia](http://en.wikipedia.org/wiki/Rings_of_Saturn#Formation_of_main_rings) and [NASA](http://science.nasa.gov/science-news/science-at-nasa/2002/12feb_rings/) each explain the two different sides; the other links in my answer are also informative2. I like the 4-billion-years theory because there would have been a lot of extra (i.e. non-planet/comet/asteroid/whatever-forming) material in the original protoplanetary disk that needed to go somewhere. But I'm by no means an expert. Same goes for the other ringed planets (Jupiter, Uranus and Neptune), by the way.
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> Could these moons retain their non-equatorial orbits and, if so, could they influence planetary detritus in such a way to form rings in more than one planar space?
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[There's a reason why the planets (and, by extension, their moons) are all in the same plane.](https://astronomy.stackexchange.com/questions/130/why-do-the-planets-in-our-solar-system-orbit-in-the-same-plane)3 There are, however, [some reasons for an orbit to not be in the same plane](https://astronomy.stackexchange.com/questions/768/what-might-cause-a-planet-to-have-a-significant-tilt-in-their-orbit/795#795).4 The idea of a captured moon is the most probable here.
I don't trust reddit (no offense to all who use it) when it comes to science, but a few comments later down were rather interesting (emphasis mine):
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> Das\_Mime: Planets bulge at the equator and thus will exert a tidal force that preferentially pulls objects into orbit around the equator by disrupting non-equatorial orbits.
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> NW: Will our moon eventually get pulled into an orbit around the equator?
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> Das\_Mime: Its orbit is thought to be gradually moving closer to the equator over long time periods, but the closer it gets to the equator the weaker the effect is. **When a body has multiple moons, they have a mutual gravitational interaction which can force the moons to orbit in the same plane or else be ejected, since that's the only stable configuration**. Earth's Moon is a lone satellite and orbits at a somewhat large radius from the Earth (though not even close to as large an orbit as the outermost satellites of Saturn or Jupiter), and moreover the Earth's equatorial bulge is quite modest, and so the effect is rather weak.
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> Since Earth is not an especially oblate spheroid (a difference of about 0.3% between the polar radius and equatorial radius), its equatorial bulge doesn't have a terribly strong effect on the Moon's orbit. However, the tidal interaction between the Moon and the Earth's bulge (as well as between the Sun & the Earth's bulge) does cause the precession of the equinoxes, a change in the orientation of Earth's polar axis.
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> **Saturn, on the other hand, has a fairly extreme oblateness, about a 10% difference between the polar radius and equatorial radius (it's even noticeable to the eye in images of the planet and so it has a much more pronounced effect on the orbital orientation of objects near it.** Additionally, if we're talking specifically about Saturn's rings, they extend no more than ~150,000 km from Saturn's center (~60,000 km of which is taken up by Saturn), whereas Earth's Moon orbits at about 380,000 km from Earth's center (Earth is only ~6300 km in radius).
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Another possibility is to have rings of Hot Jupiters warped by tidal forces from their parent star (see implications for detection in [Tusnski & Valio (2011)](http://arxiv.org/abs/1111.5599)). This was also mentioned in [an answer by JRover](https://worldbuilding.stackexchange.com/a/30055/627), citing [Wikipedia](https://en.wikipedia.org/wiki/Exoplanet#Rings) and [Schlichting & Chan (2011)](http://arxiv.org/abs/1104.3863).
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1Shameless self-promotion.
2More shameless self-promotion.
3Man, I'm adding lots of plugs for Astronomy.
4I'll stop eventually.
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I am designing a genus of eusocial, high-temperature, extraterrestrials from the planet [61 Virginis b](https://en.wikipedia.org/wiki/61_Virginis_b). They are based on [tungsten chloride](https://en.wikipedia.org/wiki/Tungsten_chloride) and use [sodium chloride](https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Other_solvents_or_cosolvents) as a solvent. This species has sessile queens that can grow up to 1,000 feet. This is facilitated by the fact that upon maturity to stage, they mostly consist of their shells and all fleshy bits have been reduced to branching tendrils that creep along the inside of the shell making the internal cavity.
The problem is this planet has a very high temperature, around 800 Kelvin, which is perfect as the triple point of sodium chloride, but bad for tall structures, even ones made from tungsten. To add insult to injury the gravity of the planet is five times that of Earth, making tall structures even more unfavorable. [The shell needs to be hollow because the harams of male workers retreat into the shell and it's the only way the males get access to reproduction](https://en.wikipedia.org/wiki/Osedax#:%7E:text=Male%20Osedax%20are%20microscopic%20dwarfs%20that%20live%20as%20%22harems%22%20inside%20the%20lumen%20of%20the%20gelatinous%20tube%20that%20surrounds%20each%20female.%20An%20individual%20female%20can%20house%20hundreds%20of%20these%20males%20in%20her%20tube.%5B11%5D%5B12%5D). The hollowed cavity is also the only way the queens can have their harems regulate their body temperature, through the closing and opening of [pores for ventilation](https://www.imperial.ac.uk/news/190633/x-rays-reveal-secrets-termites-self-cooling-self-draining/#:%7E:text=The%20pores%2C%20which%20lie%20in,helps%20keep%20the%20heat%20inside.).
So bearing all this in mind what shape should this shell be so that it can grow up to 1,000 feet without it collapsing due to gravity or the heat making the tungsten compounds it consists structurally unsound?
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We're going to have to assume that the queen can't roll over. I can't imagine any structure that tall that could be laid on its side.
With that restriction, your shell would be a fractal agglomeration of [catenary curves](https://en.wikipedia.org/wiki/Catenary).
[](https://i.stack.imgur.com/ijEtGm.jpg)
This shape is the shape that best resists gravity. A [flying buttress](https://en.wikipedia.org/wiki/Flying_buttress) is usually designed as half of one of these. An organic process could readily adjust the shape in order to keep internal supports at the right angle to fight whatever pressure is applied, but this is the shape that they would wind up using, at numerous scales.
[](https://i.stack.imgur.com/G6aj4m.jpg)
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I think your sessile Queens shell should be cone-shaped. A cone is stable in high gravity because the wide base spreads out the weight and the narrow top has less weight to support.
Because the cone should be hollow in your plot, the shell can be supported by vertical ridges on the outside, to give it extra strength. Additionally, it should be thicker at the bottom than at the top to be able to handle gravity (i.e., the cross-section of the shell is thicker at the bottom).
For the material, [tungsten carbide](https://en.wikipedia.org/wiki/Tungsten_carbide#:%7E:text=In%20its%20most%20basic%20form,armor%2Dpiercing%20shells%20and%20jewelry.) might be a good choice. It melts at 2,785–2,830 Celcius, it has a high [Young Modulus](https://en.wikipedia.org/wiki/Young%27s_modulus) (higher than steel), and hell it is even used to make armor-piercing ammunition when depleted Uranium is not available.
So my vote goes to a cone-shaped shell made out of tungsten carbide!
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I have searched for engineering documents on the effect of temperature to strength of Tungsten. All the charts I found starts from over 1000K. However around 800K Tungsten becomes ductile, unsuitable for large constructions. However, I found the following chart showing there are alloys of Tungsten that holds their strength at much higher temperatures.
[](https://i.stack.imgur.com/bS7D6.png)
I am certain in a Darvinean hellscape like yours, life will find similar alloys that will allow them to construct incredibly intricate shells that create a suitable environment like you have described.
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**This question already has answers here**:
[How many people can you feed per square-kilometer of farmland?](/questions/9582/how-many-people-can-you-feed-per-square-kilometer-of-farmland)
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Closed 1 year ago.
This post was edited and submitted for review 1 year ago and failed to reopen the post:
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Updated to add more clarification.
**Given the following data, how large a territory would be needed to sustain a village of 500 people that has no outside contact?**
**Population:** 500 humans (approx. 400 adults in workforce). They do not eat meat but do use goats for milk/cheese/butter.
**Climate:** Moderate temps ranging from 15-85 degrees Fahrenheit with a distinct Summer(3.5mo)/Fall(3mo)/Winter(2.5mo)/Spring(3mo). Spring is the rainy season with average rain fall enough to fill holding ponds for gravity fed irrigation. Assume they collect as much water as they need to supplement during the short dry season in late summer.
**Landscape:** rolling hills with mountains not too far away. Natural wooded areas contain some plants for gathering and lumber needs. Need to determine how large of a wooded area would be needed to be sustainable based on how much lumber they use.
**Technology:** Horse and ox driven plows. no electricity. Similar to medieval era in terms of harvesting and preservation techniques. large scale use of cold cellars dug into sides of hills. They also have water bath canning techniques that are quite effective. The people use the most effective growing techniques of the era and are skilled at avoiding crop loss from diseases or insect/animal damage.
**Plant types:** Grains, legumes/beans, soy, potatoes, peas, leafy greens(spinach, lettuce greens), broccoli, various fruit trees, various berries, squashes, onions, ect. Mushrooms are gathered from nearby wooded areas. Cotton for clothing/textiles
**Products from Animals:** goats milk, sheep wool
**Animals for work:** ox and horses. more ox than horses.
**Criteria for Self Sustainability:** By self sustainable I mean a village with zero outside trade and unable to travel beyond the immediate area. They would not only need to produce their own food but also craft anything else they may need to survive. Building materials for houses/barns/businesses, storage areas to hold raw materials as well as preserved foods and crafted items. Area for work animals to graze. Raw materials needed to make storage and cooking pots. Surrounding resources must be included in the total area needed to support the village. For example the size of forest needed to supply an ongoing supply of wood and a mountain area for a quarry.
If anyone asks for more information I will add it to the post.
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## Approximately 6 km2
A reddit post quotes the US Farm Bureau saying it takes 2.67 acres to feed one person. You've got 500 people, so that's 1,335 acres.
You also have farm animals that must be fed. Reddit also says it takes 0.46 acres to feed a dairy goat, and twice that for one steer. How many goats and oxen do you have?
Goats is up to you, but I assume the desire for oxen will be driven by the size of the farms. The internet says a two-horse team can plow 7 acres per day, so using the total from above, you'd need 190 horses. But I guess you'd only need that many if you have to plow all the farmland on a single day. If it's reasonable to spread out the plowing over three days, you only need 64 horses.
The internet says it takes two acres for the first horse and an additional acre for each additional horse, so now the total acreage is 1,400. Now we need to add a few more horses, with more acreage, so let's say 70 horses & 1420 acres.
For every 2 goats you want, add 1 acre and 1/14th of a horse.
For every steer you want, add 1 acre and 1/14th of a horse.
Let's assume you end up with 1500 acres. How much farmland is that?
It turns out that the acre is a really small unit of area. Google says that to convert acres to square miles, you divide by 640. That's 2.34375 mi2 (or 6.070285 km2).
Of course, that's 6 km2 of crops. It makes no allowances for farm *houses*, barns, grain silos, stables, roads, rivers, mills, bakeries, dairies, slaughterhouses, blacksmiths, tanneries, tailors, carpenters, or the town doctor. So, even if every single resident lives and works on a farm (which they really can't), the village will have a bigger footprint because it needs arteries, storage, and work space.
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Centrifugal force effectively counteracts surface gravity making spinning worlds bulge and making gravity at the equator slightly less than at the poles. Hal Clement notably took this to an extreme with the planet Mesklin from *Mission of Gravity*, with 3g at the equator and around 700g at the poles... but what if we take it to an even greater extreme?
A neutron star spinning Sufficiently Fast should eventually end up with an equatorial bulge that has weak enough gravity for degenerate matter to start "re-inflating". Spin it even faster, and eventually you'll get a normal-matter rim that a human could stand on (while the sky is a series of fully-blurred circular streaks of stars).
But... what might that actually look like? What's the final shape? Would there actually be room to stand on that equator, or would it be too thin to inhabit? It would be *relatively* simple to work out the shape of an oblate spheroid of uniform density, or the equipotential surface around a point mass, but this thing is not really close to either ideal.
I realize a fully accurate answer would rely on information about degenerate nuclear matter physics that we just don't have yet, but I'd like to make this as accurate as possible for sci-fi. And if a precise answer is impractical to give, I would still appreciate references that might help me figure it out.
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While I still think it can't exist I realize my original analysis had a big problem.
The problem is an object that can't support itself (neutronium isn't a solid, it has no strength) will form an object with equal gravitational potential across it's surface. If it's 1g at the equator it's 1g at the poles, also. The star flattens out into a thin disk that I do not think has the pressure to remain a neutron star.
While I still think tides will be a big problem it's not so certain they are lethal.
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**A disk, or a toroid, or a binary. Or possibly a disk within a disk.**
[](https://i.stack.imgur.com/rDT82.jpg)
[Equilibrium configurations of fluids and their stability in higher dimensions](https://iopscience.iop.org/article/10.1088/0264-9381/23/24/001/meta?casa_token=ae4_YQkysf0AAAAA:glgRVhlot69tzEwUuPTR8Tush-pJGyrbA7kTN83A_9wtHek8VcYBJiUrSknhvSRoDY4m9Kcr21kKYyPTJsnG)
As it spins it will flatten. Like a pizza crust. If it spins more it will thin out on the middle and eventually become a ring or toroid. Spinning more will yield a binary body.
I am irritated because I once found sweet 3d model images of all these shapes and now this is the best I can find.
But in the searching I also found a scholarly paper that predicted a torus with a central core, and also a torus within a torus as possible outcomes. Torus in a torus not depicted here - click thru to the original if you are digging it. No paywall!
[ Uniformly rotating axisymmetric fluid configurations
bifurcating from highly flattened Maclaurin spheroids(https://arxiv.org/pdf/astro-ph/0208267.pdf)
[](https://i.stack.imgur.com/kwW1u.jpg)
The math governing which of these shapes is the outcomes has to do (as far as I can tell) with the nature of the "fluid" and the forces holding it together. This math is heady stuff.
So Spinny the Star has got a number of fairly unstarlike conformations it can take on. The limit of course is spin so fast that it starts shedding mass. You want to not spin quite that fast.
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I have an idea is for an FTL drive based on the theory that our universe is both Non-[Euclidean](https://en.wikipedia.org/wiki/Euclidean_geometry) and [Discrete](https://themathpage.com/Arith/cont-discrete.htm) at the [Planck Scale](https://en.wikipedia.org/wiki/Planck_length), but is instead better represented as a series of interconnected nodes. According to this theory, the speed of light is not determined by how far you must travel along a vector to get from point A to point B, but by how many nodes (each representing a planck unit separated by what takes planck time to traverse) you must cross. In a universe where space is both Non-Euclidean & Discrete, it means that one entity might need to cross 14 nodes to get from A to B whereas another might find a more efficient path jumping only 8 nodes. At the SUPER microscopic scale, this would make the effective speed of light unpredictable, but because of the law of averages, the speed of light just appears as a constant to us. I've seen this theory used before as a possible explanation for the unpredictable nature of how things can appear to jump to places they do not belong (like quantum tunneling) when observed at the quantum scale while C appears as a constant at the macroscopic scale.
This is where my idea for a Path Optimization Drive comes in. Non-Euclidean/Discrete space theorizes that C appears constant and space appears Euclidean based on averaged out probabilities, and that space appears continuous because we cannot measure what happens at the planck scale. But, if you were able to manipulate your path through space to only take the most efficient routes possible (basically determining the best possible outcome for each quantum action), it seems like you should be able to effectively exceed the speed of light.
**Here is a visual representation of what I am talking about:**
[](https://i.stack.imgur.com/wyX5P.png)
While I've often read that quantum physicists often observe things in places they do not belong, I do not know by how much. I'm sure scientists have written off many such things as measurement errors, but for purposes of my setting, I would consider such events as evidence of a really efficient random path being taken. **So, what I am trying to do is figure out what the most extreme examples of "how did that get there so fast" observations ever made in quantum physics are and how to use that as a baseline for figuring out how fast a ship could go if it could reproduce that phenomenon with every action taken by every particle that makes it up.**
As for comments about computational limitations: I know that it would take the computational power of a computer larger than the observable universe to actually do this; so, my thought for the setting is that someone who discovers that the quantum scale is not actually as random as it appears so that he is able to apply a heuristics algorithm to improve his chances of going fast instead of actually calculating the exact best route. This algorithm allows very subtle, finely tuned magnetic fields to gently guide matter in a pattern that typically follows an optimal path.
My thought is that this would not just allow a ship to go faster than light, but do so without needing a world-endly-powerful source of energy since you are basically just applying microscopic vibrations to go faster.
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# Don't compute!
This is not a complete answer, but I think it might solve one of the problems, and it won't fit in a comment.
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This is only a problem if the drive works by comprehending a substantial portion of the "planck graph" and then solving the TSP problem over that graph. So don't do it that way.
How else?
Lighting strikes along the path that offers the least resistance between the sky and the ground. It's my understanding that this happens in a million tiny steps, each taking a fraction of a second. Multiple paths are explored in parallel, and ones with unfavorable resistance gradients are abandoned quickly; the path ultimately taken is the one that held up at every step along the way.
Also, if you're lost in a dark cave, one way to find the exit (at least in stories -- I'm a city cat) is to head towards the feeling of wind.
So let's suppose that this drive works on the assumption that the physical system of the universe is already solving for the TSP in continuous time, and that we can piggyback on that solution. The drive operates in tandem with some kind of sensing equipment that examines subatomic particles or EM radiation which is traveling along the graph. Whatever that population is, let's call it "travelers" for now. The sensor tries to gauge which travelers have had a shorter journey, and the engine then heads down that path.
So, what can serve as travelers? It's got to be something that's everywhere, and it has to have properties that are theoretically measurable.
My first thought would be cosmic background radiation. It's everywhere, and I imagine we can make predictions about its current temperature based on its age, and we know what speed it's supposed to be traveling at. So, maybe it's not a reach to say that if a particular packet of CMB is a little warmer than normal, it has traveled along a shorter route, which means we should go in the direction it came from. (Or maybe I have that backwards.)
Or maybe you're comfortable handwaving how the sensor works.
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In my world-building project, a decades long orbital conflict has resulted in the trashing of Earth's orbit with massive amounts of debris, shipwrecks, and space junk. However, after an anomalous terraforming event, all this space junk magically consolidated into one large ring that circled the earth around the equator.
Is it possible to create a ring out of space debris that is visible from the surface? I am aware that the mass required to create a ring with the likes of Saturn would be practically unfeasible, and that the ring would likely prevent space exploration and result in space debris showers, but would such a ring be able to last for longer than, say, 100 years? Is there a way to calculate/derive how long such a ring may last until it is eventually destroyed by gravitational forces of both the moon and sun?
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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.
**Very Likely to Be Highly Unstable**
The length of time that the ring stays in orbit would depend on a large amount of factors, for instance, the general type of space debris and the distance between the rings and the Earth, not to mention that the amount of space junk makes Kessler Syndrome very likely so the ring will be self destructive.
But beyond that, [this](https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1951.0013) paper on Saturn's seems to indicate that there's a threshold that the ratio of *m*/*M* needs to be under that is required for ring stabilization, where *m* is the average mass of the objects within the ring and *M* is the mass of the planet its orbiting. Saturn has a mass close to 2 magnitudes higher than Earth and the particles of its ring are mostly small crystals, which have a mass several magnitudes smaller than your average piece of space junk. Saturn's *m*/*M* ratio would be far, far smaller than Earth's in this scenario, so while Saturn can have it's rings, this space junk ring would be highly unstable and unlikely to last for any significant period of time. Admittedly, the paper does not indicate an upper limit of the ratio, but given the difference, it's a fair guess to say that the ring is unstable.
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I have an idea for a space habitat [**edit**: as in, a habitat on another planet or moon, not in open space, apologies for any confusion!] which consists of two concentric domes made of tough, transparent material, with about 1 metre gap between filled with water. This serves as the habitat's reservoir of drinkable and usable water, and doubles up to help shield the colony from radiation.
My question is how this set-up would fare against a micro-meteorite strike, the kind that might pierce the domes with holes between 1-5cm in diameter. My intuition is that the atmospheric pressure within the interior dome will be more or less maintained following the impact, as while the water starts to sublimate out of the outer dome and leak through the inner dome, the air from the interior is kept from rushing out by the leaking water acting as a plug.
Would this work, or am I misunderstanding how water would behave in this situation? Would this work significantly differently on an environment like the moon with almost no atmosphere whatsoever versus an environment like Mars with a present but very thin atmosphere? For the sake of this query, we can assume that the materials used are sturdy enough and constructed in such a way as to not shatter or buckle when struck with minor projectiles (though I'd accept there'd be an upper limit where if this was struck by a more macro meteorite the thing would just break apart).
If water is a no-go for this concept, are there alternative fluids that would work? Another idea I had was if the water was treated with a gelatin-like concentrate that greatly increased its viscosity.
**EDIT:** Adding a diagram for clarity:
[](https://i.stack.imgur.com/3Mm8p.png)
1. The planetary surface, with the habitat potentially built within a natural impact crater.
2. The habitable environment within the domes.
3. The inner dome (this may include an integrated heating element to keep the water from freezing over).
4. The water (or other appropriate fluid).
5. The outer dome.
6. The exterior environment (think Moon- or Mars-like).
7. Pump/water treatment mechanism. This takes water that is mined from the surface and water that has been recycled from previous use, adds any substances that may need to be mixed into the water, then pumps up into the inter-dome layer. Water is removed from the base of the dome as and when it is needed.
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Here is how I understand the question - there is a dome (or sphere, or cylinder) filled with water enclosing a smaller dome / sphere / cylinder filled with air where human or equivalent lifeforms live. Struts or equivalent structures keep the inner chamber in a fixed position with respect to the outer chamber (ie the air-filled chamber is not free-floating in the water-filled chamber). A micrometeorite has punctured both the outer hull and retained enough energy after penetrating through outer hull and the water (more on that later) to penetrate the inner hull. Note that the water-filled chamber should not be *entirely* filled with water - in order to allow for inwards flow, outwards flow and expansion/contraction when ice forms or melts there will be some gas in the chamber.
[](https://i.stack.imgur.com/cY4YS.png)
The outer hull interaction is obvious - water will start leaking through the outer breach to vacuum. If the water is cold enough to form a layer of ice inside the outer hull then this leak may be quite slow - the micrometeorite will have punched a hole in the ice, but the hole is likely to be plugged by ice fragments or swiftly freezing water. In this situation the only mechanism for leakage is sublimation of the ice, which is likely to be slow enough that there is plenty of time to conduct an EVA and plug the hole from the outside. However, if the water near the outer hull is existing at a relatively high temperature and/or if the structure is spinning to provide artificial gravity then the leakage rate will be considerably greater.
The inner hull interaction depends on a few factors.
* If the "air" chamber is maintained at a lower pressure than the pressure in the "water" chamber, then water and/or gas from the water chamber will flow through the breach into the air chamber. (This would also present an ongoing maintenance risk, as any leaks in plumbing fittings would result in water flowing inwards.)
* If the two chambers are normally maintained at the same pressure then air would slowly leak from the air chamber into the water chamber as the pressure in the water chamber reduces due to the leak.
* If the air chamber is normally maintained at a higher pressure than the water chamber (bad idea) then air will force its way into the water chamber and (slowly) increase the pressure in the water chamber, resulting it a more rapid loss of water.
There are unlikely to be any weird effects at the inner hull interface unless the air temperature is below the freezing point of water, which appears counter-intuitive for a habitat.
However, this design has some considerable benefits, if there is the lifting capacity to put the massive required quantities of water onto the space station / spacecraft.
1. Unless the water shielding is dealing with truly massive amounts of incoming radiation, it will still be safe to drink. As noted in [this](https://physics.stackexchange.com/questions/101433/why-doesnt-a-nuclear-fuel-pool-become-irradiated) Physics SE question, irradiating water will turn some of it into deuterium, which is stable and only slightly toxic. The likelihood of the deuterium turning into tritium in a nuclear fuel pond even is low enough to be trivial. "Radioactive water" generally means "water that has been contaminated with other elements / compounds that are radioactive", the water itself is generally pretty safe.
2. [This](https://space.stackexchange.com/questions/1336/what-thickness-depth-of-water-would-be-required-to-provide-radiation-shielding-i) Space Exploration SE question has answers that suggest that a 3m thick layer of water will provide protection equivalent to living on Earth's surface against radiation dangers in space. Three metres is nice if you think about [this](https://mythresults.com/episode34) Mythbusters episode examining the penetration of different bullets into water. While micrometeors may have relative velocities much greater than even a 0.50 round, there are good odds that a good, thick layer of water will slow a micrometeor enough that it will not penetrate the inner hull.
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I don't think this is going to work too well for mechanical reasons. I have seen a related idea that should work better, though:
Put your habitat into the ground (say, a crater) and cover it with a **flat** layer of water. You want more water, though--the weight of the water and structure should match your atmospheric pressure--now you don't have a huge span that you need to support somehow, you just need enough strength to keep it flat (it would prefer to fill any dip.)
Pressure hull and radiation shield in one and it would fare pretty well against the small debris.
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I'm no space expert, but my limited knowledge says that this should work, but don't quote me on that. i also think that maybe a non-Newtonian fluid would work well here(again, I'm no space expert. Don't trust only me, find other more reliable sources as well) as when the meteorite hits, it (should) tense up, and although the vacuum of space is sucking everything out, I think it would last a bit longer than water. You should also use the liquid of this 'space buffer' not from the drinking water, but from the water that's been used and is going back for reprocessing(unless you have unlimited water, then it doesn't really matter) so that it's not as big of a deal if it's all sucked into space.
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*Assumption #1: when you say "space habitat" you're talking about something in the vacuum of space.*
*Assumption #2: the water is heated to keep it from freezing in the first place and is not kept at a super-high pressure, which would force it to become a solid. Which wouldn't actually matter that much, read on.*
**Problem: Drinking water sublimates in the vacuum of space.**
DISCLAIMER: I readily admit that this is not my area of expertise. If someone points out a correction in comments (hopefully with a pointer to a source), they're right. If I'm dead wrong (which I may very well be), let me know and I'll delete the answer.
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I don't have the background to tell you how small the hole must be, but there's a size above which you lose all of your water to space very quickly (if not explosively) because it sublimates too quickly to freeze inside your construct.
Below that hole size, the water may have time to freeze *inside the sphere* before it sublimates entirely. After that you start losing water from the frozen state through sublimation into space. Eventually, you lose all the water. (In other words, you lose all the water either way, it just takes longer as the hole gets smaller.)
The problem isn't temperature — it's pressure. You'd need a fluid that can exist in a solid state when exposed to a vacuum that can also act as a radiation shield (and could potentially, with some chemical transformation, provide drinking water for the trip — a bit of a tall order, that one). I know of no such fluid. If I recall, [heavy water](https://en.wikipedia.org/wiki/Heavy_water) would act as a much better radiation shield than normal H2O, but I think it would also sublimate.
Conclusion: meteors of all sizes are not your friend. Armor, on the other hand, is. So are deflectors, but they're [Clarkean magic](https://tvtropes.org/pmwiki/pmwiki.php/Main/ClarkesThirdLaw), and I suspect you're trying to avoid that.
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In an alien world, due to changes in the ecosystem animals that were once mostly arboreal started having to spend more time in open plains, adapting to fill a new niche of grasslands/bush eaters and predators. The predator in question evolved from a creature with long, four-
fingered limbs, employing knuckle walking on the ground to conserve its claws, which it used for climbing and taking down prey.
In this scenario, could a previously arboreal predator maintain its knuckle walking while becoming a predominantly cursorial predator? What changes would their front limbs suffer to allow this?
*Additional information*: The creature is roughly the size of a small spotted hyena and was originally a quadrupedal digitigrade, with limbs ending in structures similar to zygodactyl birds (2 opposable digits, slightly smaller than the two middle digits, with the middle ones being used for knuckle walking). Its prey was also originally adapted for arboreal life, and there were no other predators of prey already filling the new niches. In the new environment there are still trees, which it will climb for resting, like some modern day big cats. Its neck has 15 vertebrae and is flexible like an owl's, previously used to search for prey along with its sharp vision. The mandibles aren't used in active prey takedown. Its overall skeletal structure is similar to our world's due to coming from an similarly structured ancestor (yes, I know how unlikely that would be).
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In order to become cursorial, the knuckles would have to become more hoof-like, and the bones above the knuckles would thicken and extend to support the animal's weight
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It is possible, but the creature's "hands" would need to evolve towards hoofs or something similar. The middle two "fingers" would evolve to become strong enough to support the animal's weight for faster walking. The joints of the middle two "fingers" would have limited mobility and would only be able to hook onto trees for climbing.
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For context, I was reading about various research groups installing implants and cameras onto insects to use them as reconnaissance drones in high risk areas.
I’m wondering how feasible it would be, to upscale this idea, to genetically engineer insects to appropriate sizes and enhance them with the required bionics for control via software, and manipulation of their physical environment. Essentially piggybacking on a couple billion years of evolution to produce a versatile cyborg workforce that might be of use in the construction industry or maintenance.
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Well, the main issue here lies in how arthropods work: their growth is directly related to the amount of oxygen in the air. You see, arthropods have respiratory systems that basically takes oxygen directly to their tissues. That means their muscles virtually don't tire out, but it comes at the cost of being dependent on how much oxigen there is. In the case of insects, as their tracheas work through the diffusion of gasses, once they start to grow, it starts to become a problem, as less oxygen gets through, until they reach the size limit, which for land arthropods is that of a crustacean, the [coconut crab](https://www.britannica.com/animal/robber-crab), and, despite being strong enough to snap a bird's wing, they're rather slow. During the carboniferous earth, as oxygen was available in much higher concentrations, we could have animals like the 2 meter long arthropleura or the giant dragonfly Meganeura, but nowadays, not so much.
So basically to make insects grow without slowing down you'd need to either 1- bioengineer them to have entirely different respiratory and circulatory systems to match more those of vertebrates, allowing for bigger growth, or 2- alter them to allow for indefinite molting, raising them in oxygen rich environments and sticking oxygen tanks to their breathing apparatuses once they had to leave to the outside. Neither sound that effective for mass production. I'd recommend instead doing what scientists already are doing: researching insects and other arthropods to integrate their special abilities into robots, such as drones that employ the dragonfly flying abilities or rescue robots capable of compressing themselves as roaches. Those are easier to produce, take less time to be ready and don't need oxygen tanks stuck to them
Note: to use normal sized insects, it's already being considered in the form of [cyborg beetles](https://www.smithsonianmag.com/smart-news/researchers-make-cyborg-beetles-reality-180958631/) and roaches, maybe with more technological, smaller implants. However this can be considered unethical, as you're basically forcing the animals to do what you want by essentially hijacking their bodies, and the concept of being a passenger aboard your own meatsuit is quite the theme for a Sci fi horror story in itself.
Edit- sorry, it is true that tracheas are exclusive to insects and other arthropods have other different types of respiratory system, and my answer seemed to say so otherwise, however I decided to focus on insects in this question simply due to their wide distribution, the already existing research being conducted on them for your purposes and the fact they're the only arthropod group capable of flight.
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This question on space stack begins to tackle how a bird could fly inside an O'Neill cylinder, <https://space.stackexchange.com/questions/27665/can-birds-fly-inside-an-oneill-cylinder>.
Here is the video mentioned in the question of birds attempting to fly in zero G <https://www.youtube.com/watch?v=w4sZ3qe6PiI&feature=youtu.be>
The video shows that they can fly in zero gravity, although they seem quite disorientated.
As the above answer points out the birds should fly as normal from take off from the ground where artificial gravity from the spin of the cylinder will take affect like gravity on earth, flying with or against the spin will have interesting effects causing the bird to either dive or hover, but it is the bird flying directly through the zero gravity central axis or along the axis that I am interested in for this question.
How would their flight change as they enter the central zero gravity axis area? and assuming they had lived inside the habitat for some time and had gotten used to the environment. Would they have trouble in this area and avoid it, would they dive through it with their momentum from earlier, could they even take advantage of the area somehow?
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> How would their flight change as they enter the central zero gravity axis area?
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Once they're *accustomed* to it, I expect they'd flap their wings less often, since they don't need the lift to stay in the air.
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Assuming there is air up there, I expect they'd be fine. Most likely "flight" in the region (again, once they figure out what they're doing) would be more like penguins swimming. Like in the video, they probably won't maintain a particular orientation. (Again, I believe this is already the case for penguins.)
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Would they need to? I don't see any reason why, unless the air is really thin. (If it is, they would probably avoid the center, treating it as 'too high to fly'.)
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Yes! In fact (again, *if there is air*), I can't imagine that they *wouldn't* take advantage of a space where they don't need to exert themselves much to stay aloft. Terrestrial birds already do this with updrafts ("thermals").
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In my fantasy setting, slimes are a species of giant (about eight cubic feet), single-celled amoeba. They have the ability to freely change their state and viscocity, being able to "melt" into a slurpy fluid close to water, harden into a dense putty, or anything inbetween.
What organic mechanism might allow the slime to change state like this?
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## Strong Cytoskeleton
If your slimes are single cells, you're going to run into some huge problems. Cells are filled with a fluid called cytoplasm, which is contained within the cellular membrane. In essence, cells are like little water-filled bags. If your slime is only one cell, it can't be very slimy, because you don't want that bag to burst and leak the slime's guts everywhere. Your slime's ability to move, and its ability to "flow" or "leak" will be constrained by its outer "skin" as long as it's a true cell. I'm going to answer your question as best I can while maintaining the "one cell" constraint.
If you really want to have just one cell, I suggest evolving a very strong [cytoskeleton](https://www.nature.com/scitable/topicpage/microtubules-and-filaments-14052932/). This is the organelle that gives cells structure, and helps them expand, contract, divide, and move. A microscopically-thin cytoskeleton might not work on the scale of a massive slime, but you can always make it thicker. This is a really simplified explanation of a complex structure, but it's a start.
By adjusting its cytoskeleton, a slime can achieve locomotion. It can conceivably change its shape - and by relaxing or tensing this organelle, it may be able to act more fluid or more rigid. Various cytoskeletal components are shown below in red and green.
[](https://i.stack.imgur.com/kS73Z.jpg)
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## Many Vacuoles
Sticking with the "giant cell needs need giant organelles" theme, another direction to move in is vacuoles - the large, storage organelles that plant cells use to hold water. In plants, full vacuoles provide structural support, while empty vacuoles leave plants sagging.
You could give your slimes thousands of small vacuoles that similarly allow for different degrees of cellular rigidity. Slimes could move water in and out of their vacuoles to go from rigid to soft. Keep in mind that moving water into or out of the cytoplasm wouldn't cause a net change in viscosity. Your slimes would need to soak up ambient moisture or leak some water to become more or less fluid.
[](https://i.stack.imgur.com/hUExQ.jpg)
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## Thick Cytoplasm and No Cellular Membrane
If you want your slimes to be "cells" in that they aren't composed of smaller cells, you might be able to get away with stripping away the outer membrane that keeps the cytoplasm contained. You would need to thicken the cytoplasm (inner fluid) a LOT so that the cell doesn't just turn into a puddle. No cell ever seen on Earth has done this, but if your slimes are large enough and thick enough, they might be able to pull it off. Getting your cell to move with no membrane to push or pull on would be really difficult, unless you developed "muscle" organelles. But it would be runnier - and thus a lot more "slimey" - than a single-celled organism.
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Starting with this definition of viscosity — a quantity expressing the magnitude of internal friction, as measured by the force per unit area resisting a flow in which parallel layers unit distance apart have unit speed relative to one another.
I think that physics of friction — causation not results — is not well understood. But one theory of a cause of friction is coulombic attraction. This also is used to explain ideas like wet-ability and why teflon works.
If your slimes molecules could vary their charge by generating a dangling hydrogen bond, then your slimes molecules would repel each other and reduce the Van der Waals forces (attractive force between molecules). This could explain how they become less viscous.
To become more viscous, they either selectively absorb or generate dangling hydrogen bonds causing the molecules to attract each other, strengthening the attractive forces.
To reach maximum viscosity, they might make every other molecule postive and the others negative, maximizing the coulombic force which would pull them together and maximize the van der waal force.
They might also twist their molecules to make them ‘smoother’ or ‘kinkier’ so that the molecules interlock tighter when closer or slide easier when far away.
I doubt any of this is actually true, but it has the virtue of sounding plausible. Hopefully, that is enough for your need.
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We all know the tale of Jack and the Beanstalk--a farmboy sells his cow for some "magic beans", which in turn grow into a mountainously tall stalk that led him to the land of a giant. Now, scientifically speaking, the only way for Jack to meet the giant is if the beanstalk led him to a habitable world with lower gravity.
Which was the sort of thing that "Jack", a member of the mad scientist illegal terraforming community, wanted to take advantage of when the real scientific community discovered that one of the alternate Earths has an iron-rich core the exact same size as ours is, but hidden beneath a smaller crust, which compresses the mantle. This combination of smaller crust and same-size core means that the planet would be warm enough to support liquid water, therefore life. For him, it is the perfect place to turn the story of "Jack and the Beanstalk" into an actual ecosystem, complete with smuggled stores of fabacean seeds, or "beans", just to see if the lower gravity would be enough to turn these small herbs into giant plants that anyone named "Jack" could actually climb up.
But here is the thing--if the crustal diameter is too small, therefore compressing the mantle too tightly, then the crust would liquefy, turning the surface into a volcanic hellscape. So in an alternate Earth where the core is the same size, how much smaller would the crustal diameter be for this world to be livable instead of hell?
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I'm going to be honest, I think this sounds a little too far outside of science for this to work.
Base requirement is that the Earth and moon would have to be completely different because they would need to be closer and tidally locked so that the moon doesn't immediately rip the beanstock out of the ground. Pluto and Charon are a great candidate for that, but they are frozen because of the distance from the sun, and are too small to hold an atmosphere. Of course, if you increase the size and bring them closer to the sun, they end moving too far away to be feasible.
The tidal locking would also cause the Earth to be dramatically colder on the moon side because it would experience much colder nights, while the other side would be warmer and drier because the moon produces the tides, so oceans may be likely to accumulate more on the moon side. When I say warmer and colder I don't mean like greater difference than the Sahara and Antarctica.
I guess it might be feasible with those parameters, but that's a hell of a lot of handwavium. There's a reason fantasy and scifi don't usually overlap well unless you just kind of drop real science.
I know you were primarily asking about the crustal diameter, but I think you have a few more bigger issues before that really comes up. Is the mantle size different in anyway? That would definitely have a greater affect, because the crust is so thin around the edges of the Earth, that changing that alone would essentially have next to no affect except make the surface molten as suggested. A much smaller mantle, which would likely be necessary for this scenario would however have drastic affects on the Earths internal heating. I guess this is just more of a few things to consider.
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I think a good reference would be the inner earth [temperature by depth](https://upload.wikimedia.org/wikipedia/commons/9/9e/Upper_mantle_temperature_profile.png) which clearly shows that you can't shave off more than a few kilometers (and that is negligible in the big picture) of crust before you cross the uncomfortable 100°C region where life would be severely unlikely.
If you want to take away the largest amount of mass with minimal effect to temperature and all the other crap I would suggest shaving off large amounts off the mantle and maybe the liquid outer core. The temperature does not increase that much after a few hundred or thousand kilometers and what really brings the temperature down is the solid crust anyways.
There is a good chance that a smaller earth would turn completely solid though, since the volume/surface ratio would change drastically in the favor of cooling off.
(Yes, homogenization is also bad for keeping temperature, but you still need to consider that a 10 fold decrease in diameter for example would decrease gravity a thousand fold and increase the cooling rate by 10 times)
Last thing you have to consider is that gravity is not the only limiting factor for animal growth on a planet!
A very important measure is the volume to surface ratio of an animal as defined by rubners surface law or square cube law in general.
It basically means that a larger animal will have to slow down its metabolism in turn in order to avoid overheating which is also why we see large animals with artificially raised (unnecessary) surface (look at elephant ears for example).
So your giants would, depending on their size, be either very dead after a few seconds or have an incredibly slow metabolism as in, they pretty much don't move at all.
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## Intro
There are a lot of physical issues with this planet being connected by the end of a bean-stock that is also connected to Earth, but if its magical anything is possible.
I'm going to first examine the composition of our new planet and how we might approach the minimization of its radius.
## Earth-Like Gravity
The most obvious issue for minimizing the radius of this planet is mass, since I'm assuming you want the gravity to be at least somewhat similar to Earth's. For the smallest dimensions of a Earth like planet that are physically possible the density will be the most important parameter, which of course constrains composition.
Now there are a few issues that really constrain the possible solutions to the problem. First if the core has to have the same diameter as that of Earth and has to have the same iron based composition, then we'll start there. The core is composed of an inner and outer component, so I'll assume the core in it's entirety.
From my handwavey calculations I guestimated the mass to be about $8x10^{23}$ kg, from researching it a bit I found the core is estimated to be about $1.9 x 10^{24}$ kg which is about a third of the Earth's total mass. [O.G. Sorokhtin et. al, Dev. in E&ES, 2011] I'll use this later figure.
The total radius so far is about 3500 km. We need to account for a remaining $4x10^{24}$ kg of mass. We want a dense material, but it must not be denser than the core. If we add another 1850-2000 km for the mantel we can get an average density between 7.7-8.7 $g/cm^{3}$. This is not unreasonable for a metallic composition. However, this is another issue altogether; metal is way too thermally conductive to work if the core is to be the same as Earth's. A particularly cold core wouldn't actually affect the surface temperature (after all this is determined atmospherically and not from the internal temperature). However, a cold core would result in a weak or lack of internal dynamo effect and no magnetic field, which of course make life impossible. To resolve this, you could force it to work, of course the solution is completely contrived and result in some rather bizarre things happening; a mix of heavy metalloids and oxygen might do the trick.
So now we have a reasonably dense planet with the same gravity as Earth. Coming out with a planet about 5500 km including the crust, our planet will still have near Earth gravity while being a bit smallar. However, our planet is still much larger than Mars. The circumference of this planet would just be a few thousand km smaller than Earth. While this is quite a bit, it probably wouldn't feel too much different when on the surface. The curvature of this planet would be noticeable at lower altitudes, but a few thousand kilometers isn't as much as it sounds when we consider that the the Earth's circumference is 40,000 km! If someone is in the US for example, any place within the continental US is no more than 5000 km away.
## Other options
Now, you mentioned a lower gravity. But the question is how much lower do you want to go. The lower the gravity, the more bizarre the inhabitants of this planet. I'm not much of a biologist, but I'm aware of the basic effects of lower gravity might have upon organisms. If the sort of animals and plants on this planet were similar to the ones on Earth, they would probably tend to be taller. They probably would be more massive as well since the limit to being crushed under ones' own weight would increase. But the animals wouldn't be the only problem here.
Lowering the gravity allows for less extra planetary mass as well and possibly less gravitational acceleration. But we'll still need a sizable mantle for a variety of reasons.
If we just isolate the Core, we actually get more gravitational acceleration than on the surface of the Earth: about 11 $m/s^{2}$ compared to our 9.81 $m/s^{2}$. A fairly thick mantle will still be necessary or else the mantle will be crushed under the gravitational attraction as well as being melted due to the heat transfer. There's also the problem of the core losing all the heat and another problem of no magnetic field as described above. Furthermore the outer core is fluid (the inner core is solid) and the Earth's dynamo is primarily driven by the outer core, with convection cycles running up into the lower mantel.
It is often tempting to cobble together basic calculations using hand-wavy equations for heat transfer, perhaps using the density of a candidate composition to estimate how thick our mantel might be, maybe we might go from there to solve the gravitational acceleration. This unfortunately would result in patent nonsense no better than just making something up which sounded nice. To properly get a sense of the interactions which go into these calculations we would need to create an equation of state for this planet using the interplay among pressure, heat and temperature. From this we can get a sense of how the pressure and density interact and how heat would transfer for various materials which are allowed under the density/pressure constrains. To properly do these calculations would require an entire thesis unto itself.
If you are interested in seeing an example of the sort of calculations required, see
[<http://articles.adsabs.harvard.edu//full/1980LPSC...11.1999A/0001999.000.html]>
which contains the article "Equations of State in Planet interiors" by Orson Anderson and John Baumgardner.
All in all, insisting that the core of the bean-stock linked planet must be the same as Earth's core, in both composition and heat, seriously restricts the possibiities for how realistic the size can be. For the resulting planet to be realistically suitable to an Earth surface, it will end up having a size not to far from Earth's current size. As we've explored, keeping the Earth like gravity will result in a very Earth sized planet. Allowing the gravity to be less than Earth's will decrease circumference a bit, but I would not suspect the results to be too extreme.
The interesting thing about systems such as these, is that the interplay found in the EoS really restricts the possibilities. I'd estimate that at the smallest, you'd end up with a planet not too differently sized that the one described above with Earth like gravity.
## Small Earth-like planet with low gravity
A possibility for envisioning an Earth-like planet with low gravity would be to have a much smaller core. The pressure of Earth's core is still too low for iron/nickel to be created from pressure alone. As regarding the dynamo effect, many materials can produce dynamo effects in theory, Iron is not special at core temperatures as it loses its ferromagnetic properties above the Curie temperature which is well below the temperature in Earth's core. So there are lots of choices for materials. Mars is a great example, as it is about half of Earths radius, but about a tenth of Earth's mass. If the radius were even smaller given it's mass, the gravity, which is a little over a third of Earth's, would increase.
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I'm trying to not delve too into the sciences so as to keep things fairly suitable for a space opera setting, but I'm trying to figure a few things to a reasonable degree of detail.
My question here is; Say you had a large spaceship (anywhere from a capital ship the size of the Galactica, or smaller ships like the Millenium Falcon) Given the large power requirements of both, it's necessary for them to use some large, advanced reactors, possibly multiple. Fusion seems to be a good catch-all for this. However, how would one go about attaining the inital amount of power needed to kick-start the reactor? This is obviously a bigger issue on larger vessels, where the power requirements will be higher.
The ship would have seperate systems to produce power (Main reactor(s)), and to create thrust, which would be seperate engine powerplants, using most likely a different type of fuel. So far my best idea has been to use the engines to kick-start the reactor, assuming the engines don't have a high initial energy investment needed, which most ships most likely would.
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Various fusion reactor designs are not intended to be run in a steady state, but rather are pulsed (there are a bunch of reasons for this that I won't go into here, but suffice to say that fusion is hard, and fusion of stuff that requires substantially higher temperatures than D-T is much harder still). For each pulse, you pump a bunch of energy in alongside your fuel, and get a load of energy out, some of which you keep back for the next pulse in some suitable storage medium like an exceedingly fancy capacitor bank.
In order to kickstart one of these things, you need to charge the capacitor bank. Given enough patience, you could probably do this with a hand-crank, but realistically you might use a big solar array or simpler-to-start nuclear reactor like a good old-fashion fission pile if you're too far from the sun to use the easy option.
If your ship has a pulsed fusion rocket (which seems plausible if you want something with a high-efficiency engine with a lot of thrust, which of course you do) it'll work in practically the same way.. charge up the coils of the magnetic nozzle, throw in a fuel pellet and zap it with something suitably energetic, boom, skim off some of the energy from the expanding nuclear fireball to power both the next pulse *and* the rest of your ship as a combination rocket and reactor. After all, the engines probably require vastly more power than anything else on the ship, and if you're in combat you don't want to have your engines turned off because you'll be a sitting duck. Secondary reactors are just that.
That "zapping" phase of the engine pulse process is where all your up-front energy cost comes from... once you've got the first zap, you get a self-sustaining cycle because the fireball will charge up the capacitors to power the next zap. What you need then is a much, much smaller power source to operate the magnetic nozzle (because if it isn't charged up to full power you're going to blow yourself up), and then you just kick a thermonuclear warhead out of the back of your ship and have it go off in the focus of your magnetic nozzle. Boom, engine kicked to life, gigawatts of power instantly available.
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If a space ship has been inactive and un powered for a long time, maybe days, weeks, months, or years, there might be a complicated procedure to start it up.
I once read that large solid fuel rocket motors were tested in stands by igniting a smaller rocket inside them. The exhaust from the smaller rocket ignited the solid fuel and solid oxidizer and started the larger rocket burning. So how did the smaller rocket get started?
If someone lit a match to light a solid fuel rocket dangling inside the nozzle of a giant solid fuel rocket, he wold be inside the giant rocket's nozzle and would be burned to death if the giant solid fuel rocket ignited before he could get out and far enough away in time.
So possibly a another, even tinier rocket would be used to ignite the second rocket which would be used to ignite the giant solid fuel rocket being tested. But eventually there would be a first rocket, which might be ignited by lighting a long fuse from someplace far enough away to be safe, or by remotely activating a device that made a spark, or by remotely opening a valve causing two substances to mix and spontaneously ignite, or remotely activating a liquid fuel pump, etc.
And starting a space ship's main power generator might involve a similar sequence of less energetic actions causing more energetic actions which cause even more energetic actions and so on.
Presumably a fusion generator would need a lot of electricity to operate.
Maybe some chemical fuel might be burned in oxygen to run a little generator that provides energy to run a fission reactor. Electrically powered machines would move the fission fuel and the control rods, etc. into place and pump the coolant, and presumably steam produced by the reactor would turn a generator which generated many times the electricity that the chemical powered generator did, which could now be turned off as some of the fission produced electricity would be used to run the fission reactor.
so most of the electricity from the fission reactor and generator would be used to start and run a small fusion power plant what would generate a lot more electricity. Some of that electricity would be used to run the small fusion power plant, so the fission reactor and generator could be slowly closed down until needed again.
Most of the electricity from the small fusion power plant would be used to start and run a much larger fusion power plant. Some of the larger fusion power plant's electricity could be used to run itself, so the smaller fusion reactor could be shut down until needed again.
And repeat in as many step as as are necessary until the ship's main fusion power plants are up and running and providing all the tremendous amounts of energy needed to run the life support systems, and the weapons systems, and the anti gravity, and the slower than light space drive, and the faster than light space drive, etc., etc..
Note that fission fuel would gradually decay to non fissionable elements with time, so a fission reactor would become useless for a step in this start up process after a period of time which depends on various factors that atomic energy experts could discuss.
At a spaceport, the energy for the first step in the start up procedure might be provided by the spaceport's power generators. An exploration or war ship would not expect that service to always be available when needed and so would be equipped to start up entirely on its own.
Of course if some adventurer lands at a space port and suspects that he might possibly have to run for his life back to the space ship and take off just a few minutes after landing if things go wrong, the space ship wouldn't be turned off and un powered but left with the engines idling, more or less, so that it might be able to take off and escape almost instantly.
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**Pilot light.**
[](https://i.stack.imgur.com/JX27X.jpg)
In this future cold fusion reactor, the reaction will continue as long as it is provided fuel. If you need energy, you provide more fuel, and you can ramp it up. If you don't need energy, it powers down. But not to zero.
The analogous situation is a pilot light. A little bit of gas continues to flow and keeps the flame ready. When you need heat from your car appliance, the pilot light is available to light the main burners and ramp up in a hurry.
The "pilot light" equivalent for the reactor is lit at the factory and the reactor is provided already running. The tiny bit of energy it necessarily generates is dispersed as heat. If your ship is unattended for long enough that the fuel for your fission reaction runs out (which would be a long time) it will be a trick getting it started again.
Your fusion reactor would provide all the energy needs of your ship. It would turn a generator to produce electricity for the sound system and (laser) lights. It would superheat water and shoot it out the back for propulsion. Less superheated water would fill the Captains Hot Tub.
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Fusion reactors are nice. You could use batteries like superconductor/insulator material (<https://www.popularmechanics.com/science/a29813740/new-state-of-matter-cooper-pair-metal/>) to start up a small auxiliary reactor that turns on the big stuff. Alternatively you could store some anti-matter in some futuristic passive magnetic container and use that for the first burst of energy.
But why stop there? Storing anti-matter probably takes a lot of energy and the point of your battery is that it doesnt empty itself. The option for a full-scale anti-matter reactor presents itself. But having to run your anti-matter reactor for a decade on low-power just to preserve the rest of the anti-matter isnt the best option. So that leaves one of the more awesome solutions.
A black hole. Never miss a chance to use a black hole. Starting off with a kugelblitz created in a lab (probably at a Dysonswarm) and then fed matter until it's sufficient in size will generate a steady predictable amount of energy on par or higher than fusion reactors for quite literal millennia. Black Holes generate less energy per second the bigger they are (but become easier to feed), so if in dire need of more energy you could have several small Black Holes powering your ships. Fuel is easy to come by as anything that can be accelerated into the Black Hole, even light, can make it grow. When you dont need the energy you can feed it back to the Black Hole in the form of efficient lasers, masers and other forms of radiation or by using a fairly accurate particle accelerator that fires matter into the Black Hole. It needs to be accurate due to how the Black Hole's event horizon is probably smaller than the atoms you are trying to fire into it. The Black Hole also provides its own constant power to keep the Black Hole in place in your reactor. Dont worry about it swallowing your ship, at these sizes it hasn't got the mass to pull much in (its like expecting Mount Everest to have enough gravitational pull that people can feel it). Ofcourse it does mean that if he Black Hole leaves the reactor the power of a nuclear reactor is now blasting through your ship.
Just know that if the Black Hole reaches the end of its lifespan it'll rapidly release enough energy to simulate an atomic bomb explosion. Either feed it or eject it beforehand.
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No space magic answer: Antimatter is probably the best place to start, considering it doesn't have a high activation energy. All you need is a magnetic containment system, then meter out enough of it to start a self-sufficient fusion reaction.
Soft sci-fi answer: If you had something that can produce an energy field on the cheap that greatly decreases the activation energy for fusion to occur, you could have cold fusion with no massive energy input to start with. Theoretically, that energy field would disrupt the forces that hold atoms together, so you could easily repurpose a matter disruptor for that.
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Originally I was going to ask for help in the process of designing moons in general, but this is such a vast topic that I decided to narrow it down.
I'm trying to create rocky moons or planets. I have great ideas, but I am struggling with the realism of creating the features of the surface.
Consider the below pictures of Pluto's moon Charon, Jupiter's moon Ganymede, and Mercury, respectively:
[](https://i.stack.imgur.com/Cb3bo.jpg)
What I want is any tips or strategies on how to create the surface features (like creating craters in GIMP or Photoshop, creating striations, mountains, or valleys).
**I am *not* asking for help in designing the colors or features themselves, I'm only asking for help in *creating them* when I've already decided what to put there.**
Include a small paragraph or a link to:
1. How to draw craters
2. How to draw mountains
3. How to draw surface features in general
**Specifically, any help in creating the illusion of elevation or roughness of the surface would be appreciated.**
The problems I'm facing have to do with my planets or moons not feeling "involved" enough. They seem too simple, without enough layers of detail.
Here is an example of a lava planet I created:
[](https://i.stack.imgur.com/H764B.png)
And here is the moon, with the equatorial gash as mentioned [in one of my previous questions](https://worldbuilding.stackexchange.com/q/156117/21222):
[](https://i.stack.imgur.com/tOFgp.jpg)
**Any help I can get on how to improve these and make them more realistic would be highly appreciated.**
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Most of these you probably already know, and have already done to some extent, but if someone else comes across this post who wants the very basics, here we go:
## The structure of the surface.
On all the images of real planets, there are large features: jagged gashes across the surface, white spots with huge lighter and darker areas, changes between shades of grey and brown.
In your images, you have one noise applied uniformly. On the lava planet it looks like some sort of stepped multifractal, and the color of "red" is "red" across the whole planet. There are no distinguishing features such as craters, plumes, or other strange bits, and as a result, the "noise" looks rather artificial: it's noise, but it's too regular. Surprisingly, planet surfaces are /not/ purely noise functions. Processes like erosion can't be modeled by layers of noise.
Similarly for the moon with the equatorial gash: all the craters are the same size. Tiny/detailed, but the gash is ruler-straight (which is probably intentional), and none of the craters are larger than a fingernail. It's also the same grey across the entire planetary surface - there are no areas where there's a higher concentration of Fe2 oxide making it brown, or Fe3 oxide making it red etc. etc.
In particular, most planets have poles. These may have vastly different materials as at the poles, liquids freeze into solids creating very different surface properties.
The three reference images you have there are fantastic. Copy from them! Add streaks, notches, random white dots, dark areas etc. etc. Yup, you'll probably have to do this by hand.
## Height != Color
It's very tempting to throw a color gradient on your heightmap. But then you end up with something like this:
[](https://i.stack.imgur.com/bVb3G.png)
Pretty terrible, right? This is becase in the real world, things are pretty much never purely a function of height. On a temparate world, you'd expect there to be rivers, areas of desert etc. etc. Not a uniform "blue = low, green = middle, white = high"
The same applies to rocky and lava planets. Just because there's a crater doesn't mean the bottom of that crater will be a particular color. Maybe the meteor that made the crater was composed of one particular material, and it left a darker smudge. Maybe there was a landslide, and it exposed a strata of greenish rock.
## Lighting
For example, here are three moons I threw together all using the same heightmap:
[](https://i.stack.imgur.com/0broX.png)
Aside from all sucking at being realistic, they illustrate that the properties of the rendered surface make a large difference. The "Most real" is the one on the left, because most lunar regolith is very diffuse with no specular. In your picture of the moon I do see a very slight specular highlight:
[](https://i.stack.imgur.com/MWLfP.png)
It's not wrong, but I'd say get rid of it altogether. If you're using a renderer that uses PBR: set the roughness to 1 and the metallic to zero.
If you've got a planet with an atmosphere or water, this will obviously be different, but for rocky moons, I think it's fairly good advise.
The sun is BRIGHT. Here's another comparison shot (ignore the green stripe, it's an orbit indicator, and ignore the horrible texture seam at the poles - this moon is normally viewed from further away)
[](https://i.stack.imgur.com/U0CEA.png)
The one on the right has a sun that is ten times more powerful than the one on the left. Yup you don't see nearly as much surface detail, but sometimes that's a good thing.
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the other answers are so comprehensive .. I can only offer a link to [Terraray](https://download.cnet.com/TerraRay/3000-6677_4-75844935.html), a nice app (I use it on Mac OS X) for creating a 3D terrain model that can be used in most of the 3D modelling apps.
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Okay, we know the type-IIb FG muscle fibers are the strongest stuff we can use. So, the only thing we can do is attach more, but how?
Dragons are 180 cm tall at the shoulders with a total neck+head length of 180 cm, a body 180 cm, and a tail 280 cm. Many of the body's bones are fused together, resulting in decreased/non-existent flexibility there. The neck is long, 2/3 of the total neck+head length. The tail and neck both use a bit of [Arambourgiania](http://markwitton-com.blogspot.com/2016/06/why-giant-azhdarchid-arambourgiania.html) magic.
Dragon bones have a structure similar to [limpet teeth](https://www.researchgate.net/publication/272516448_Extreme_strength_observed_in_limpet_teeth), so basically, goethite fibers in a chitin matrix, kinda like an organic [short-fiber composite](https://en.wikipedia.org/wiki/Short_fiber_thermoplastics). Tensile and compressive strengths are 4.5 GPa on average, with the right fiber orientation, of course. There are some bones, I haven't tampered with, that store calcium and phosphorus.
Tendons received an "upgrade" as well, in the form of [CNFs](https://www.kth.se/en/forskning/artiklar/method-assembles-cellulose-nanofibres-into-a-material-stronger-than-spider-silk-1.819122), tensile strength is 1.6 GPa.
Dragon wings are broad, soaring wings, similar to that of an eagle, [reinforced with actinofibrils](http://aeroevo.blogspot.com/2012/06/feathers-vs-membranes.html).
Dragons dissipate heat through their wings and during exhalation. They use their flight muscles sparingly, and never longer than 90 seconds at a time. They eat fish, meat, fruits, and algae. The primary mode of flight is soaring.
They have six limbs in total: 4 legs and a pair of wings, sandwiched between, just far enough not to interfere with one another.
**So, I guess I'll have to pack additional muscle on the keel (mainly because of the extra pair of legs), but I want to pack it in a way that power output increases linearly with muscle weight, how can I do that?**
I do know that the force, muscles can exert, is the function of cross-sectional area, if that helps.
## Update
Figure time: I originally gave dragons a wingspan of 11 meters and a width of 2 meters. So, the dragon could be 11x2x20=440 kg and have the wing loading of the Quetzalcoatlus northropi. I'm not sure if this is correct or helpful, but here ya go.
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Addding more muscle is like the rocketequation. More muscle means more weight means more muslce required to lift it which in turn needs more bone to hold it and more fat, bloodvessles and blood to power it...
I'd go for making it lighter, and what I recommend everyone until it's promise starts to fail is Graphene based objects. Carbon Nanotubes (CNT's) or 3D Graphene (<https://newatlas.com/3d-graphene/47304/>) could both be used. CNT's would mostly fulfill a role in strenghening the material it's embedded in meaning you need less, while 3D Graphene is much lighter than steel but 10X stronger. With the sponge-like structure shown it would also allow for lots of biological stuff to run through it or simply be filled with pockets of air or other gasses. This could lighten your Dragon a lot without losing strength, meaning its muscle power can get him airborne and also be used for wrecking stuff.
Since this is all made from Carbon, one of the most abundant materials our bodies are made from, it gives you an opening for some plausibility of a Dragon, insofar a Dragon is plausible.
Additional advantages: less weight means less energy and muscles required, so less heat generation and less oxygen to burn through.
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[Is this concept for an LTA-gas' associated element lifecycle feasible?](https://worldbuilding.stackexchange.com/questions/19630/is-this-concept-for-an-lta-gas-associated-element-lifecycle-feasible)
there has been some discussion of Using other means to provide lift. Some birds are able to fly better due to air pockets in their bones. or you could use something similar to the idea given in the link i just shared. A gas so light that it provides incredible lift. A gas like this could reside inside the dragon, it could live out its whole life cycle in pockets in the bone. maybe the dragon could have control of it. the gas starts as a solid, providing no change in density. but the dragon has the ability to consciously turn this solid into the gas and expelling normally dense air, filling the space with this almost negatively dense gas when it wishes to fly. just food for thought. for a little more information about this LAL-gas contact the Inquirer of the shared question or refer to another question asked by them later on.
[What ways are there to keep a steady altitude with large fluctuations regarding load?](https://worldbuilding.stackexchange.com/questions/41582/what-ways-are-there-to-keep-a-steady-altitude-with-large-fluctuations-regarding)
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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 ran a quick calculation, and the mass of iron required to form a black hole is on the order of 10^40kg. So, suppose that in my story there is this almost much iron available to somehow be brought together in one place, but the builders don't want to create a black hole, but instead want to fuse iron into heavier elements. In the beginning a large sphere would be created, and then more iron would be added with low temperature and kinetic energy. For the purpose of the story ignore any practical issues with doing this or the usefulness thereof.
Such a large mass should, under its own gravity, be under tremendous pressure (and possibly temperature) at the core. Normally, iron doesn't fuse because such a reaction would be endothermic, but because we aren't starting with a star is it possible for such fusion to occur in such an artificially constructed setting? For comparison, the mass of the Milky Way galaxy is estimated to be only about two and a half orders of magnitude more than the amount of iron we are talking about, so this is a LOT of iron.
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# You cannot make heavier elements from Iron only
First, you seem to be familiar with the binding energy curve for elements.
[](https://i.stack.imgur.com/r7Dw4.png)
As you can see, iron is at the top of the binding energy curve, so it has the most energy per nucleon. If you wanted to 'fuse' iron into something heavier, then you need to add energy.
This is not impossible to imagine happening. The conditions inside a supernova allow [nucleosynthesis](https://en.wikipedia.org/wiki/Supernova_nucleosynthesis) of elements heavier than iron, so [incredible though supernovas may be](https://what-if.xkcd.com/73/), perhaps some super-advanced alien race could accomplish it by adding enough energy to a giant iron core.
# You need more neutrons
The problem here comes from the number of neutrons present in Iron. Iron does not have enough neutrons to form Uranium or some other heavier elements that you suggested. Having iron and only iron in your core gives you a limited number of things that you can make. You can only add nuclei together that have 26 protons in them, so the first order fusion products will all have 52 protons, and somewhere between 56 and 64 neutrons.
From a [chart of nuclides](https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html), we can see that none of these configurations is stable. 52 protons is tellurium which requires at least 68 neutrons to be stable. Thus, these short term fusion products will decay, via $\beta+$ decay, into mostly tin, with some cadmium, indium and silver and the like mixed in, depending on the initial isotopes. This decay takes elements 'down' the periodic table; tellurium has a higher atomic number than any of its products, so $\beta+$ decaying isotopes will end up with a lower number of protons once the decay chain stops at a stable isotope.
This process could potentially continue, with the tin fusing with another iron atom to make osmium, which would decay into ytterbium or hafnium; that could then pick up another iron, etc. The problem is that eventually your fusion products are going to be elements large enough that they need massive amounts of neutrons to maintain stability. While iron can be stable at 14:13 neutrons:protons, lead is only stable at 62:41; and uranium's most long lived isotope is 73:46.
Ultimately, large atoms that are sufficiently neutron deficient will start to undergo $\alpha$ decay, where they lose an $\alpha$ particle which is 2 neutrons and 2 protons. In this decay, they will rapidly drop atomic number until you are back close to where you started.
# To 'fuse' heavier elements, you need neutrons
Heavier elements obviously got created, but how? By the [r-process](https://en.wikipedia.org/wiki/R-process), where nuclei of atoms with atomic numbers above iron accumulate extra neutrons. These extra neutrons cause isotopes to $\beta-$ decay. The result of this decay is that an element moves 'up' the periodic table, gaining atomic number as unstable neutrons turn into protons. This is the only way that mostly stable elements high up in the period table (like uranium and thorium) can be formed.
The r-process occurs in two situations (that we know about). The first is a [neutron star collision](https://en.wikipedia.org/wiki/Neutron_star_merger), where there are obviously plenty of extra neutrons to spare. The second is in the core of a Type IIb supernova, the most violent kind. Much is unclear about how this works; there has only been one observed, nearby [Type IIb](https://en.wikipedia.org/wiki/SN_1987A) supernova, and the first neutrons star merger was [observed in 2017](https://en.wikipedia.org/wiki/GW170817).
Here is a chart of the source of nucleosynthesis for elements.
[](https://i.stack.imgur.com/HX23v.png)
You can see that the neutrons star merger (which is also possibly occurring in Type IIb supernovas) is how you get the vast majority of your heavy elements.
# How can you get enough neutrons?
In a supernova, and in stars in general, neutrons form from the p-p fusion chain. Two protons fuse together, a highly unstable configuration. This immediately (as in, no measured half-life immediately) $\beta+$ decays into [deuterium](https://en.wikipedia.org/wiki/Deuterium), which has a neutron. Deuterium can then fuse with other assorted combinations of hydrogen and helium to form free neutrons. In a core collapse supernova, the neutron flux is theorized to be such that extra neutrons can accumulate to the heavier elements, thereby making even heavier elements.
From your alien's perspective though, the best way to add neutrons has got to be a neutron star. If they can get their hands on a galaxy's worth of iron, they can probably find a neutron star lying around too.
# How to fuse an iron ball into heavier elements
Take a giant iron ball, add an immense amount of energy, and then throw in a neutron star. Metal!
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Short answer **You would need to add a lot of energy or extra neutrons**
As you pointed out, iron is normally the element where typical solar fusion ends. However, if enough alpha particles are present, [nickel and zinc](https://en.wikipedia.org/wiki/Nuclear_fusion), could result.
Also, [neutron capture](https://physics.stackexchange.com/questions/7131/origin-of-elements-heavier-than-iron-fe?rq=1) would require less energetic means to generate elements higher than iron. This is the contribution supernovae make towards forming these elements.
And you also mention bringing all of that iron together, which would be a very bad idea if you are trying not to create a huge lump of molten lead. Maybe bring it all together in controlled bursts, to match the amount of alpha particles or neutrons you can toss at it, then remove your newly formed elements to a safer distance.
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I have been wanting to make a carnivorous reptilian creature with the ability to speak fluently using its speech muscles and its vocal tract, it can also perform facial expressions just like how humans do, but there is a problem, humans have complex facial muscles to allow them to speak properly and therefore a complex skull structure, and being a rather layperson in science I do not know how to make a reptile have the scientifically accurate skull and facial muscle structure to allow it to speak and perform facial expressions, so as a result I cannot picture what a reptile with speech and facial expression muscles would look like.
I thought that the answerer get an idea of how facial muscles and speech muscles would be applied to a reptile and the skull alterations that are required for it, I applied some images from the internet comparing the human skull with the human skull with speech and facial muscles, a dog skull with a dog skull with facial muscles and below, a lace monitor skull with a living lace monitor lizard:
[](https://i.stack.imgur.com/QKw6e.jpg) [](https://i.stack.imgur.com/AQzAb.jpg)
[](https://i.stack.imgur.com/f3obN.jpg) [](https://i.stack.imgur.com/67rND.jpg)
[](https://i.stack.imgur.com/cYrgT.jpg)
[](https://i.stack.imgur.com/OoARv.jpg)
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Reptiles might not be suited for facial expressions at all; I imagine they would be limited in range. Primates, especially humans, are social animals - we've developed a very complex form of expressions because we've evolved to interact with others. By contrast, most repetiles don't rely on the same dynamics.
A reptile, even an advanced, intelligent one, doesn't have that ancestry that makes facial expressions important to it, and it doesn't have the same muscles to display them. Human faces are flat like a billboard to exchange emotion, which lizards lack.
The interaction between primate and reptile would be interesting, actually; by human standards, all lizardmen appear stoic and cold, but by lizardmen standards humans are just weird. They're alien creatures to each other, they operate on different social dynamics.
Instead, reptiles might develop a different means of interacting rather than with facial or verbal movements. Some gestures, like bearing teeth are universal for aggression, but otherwise reptiles use more body gestures to transmit feeling. Coiling their tail, scraping their claws would have their own meaning; they've evolved to interpret body language instead of facial movements.
Basically humans would have difficulty interacting with lizardmen, and lizardmen wouldn't easily understand humans. The individuals could learn how to decipher the others traits, but it wouldn't be as natural for them as it is between those of same species.
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One thing that just about all interstellar civilizations need if they want to be anything more than long-distance friends is a way to get from their starships down to the surface of planets and back up again. In other words, they need some flavor of shuttlecraft that can survive re-entry into a planetary atmosphere and then reach orbit again without the need for extensive ground support, as they may have to land on Earth today and Mars in a few days.
This craft must be able to:
* Re-enter and land on the surface of rocky, not-too-hot planets (Earth works, Mars works, Venus or Mercury can be excluded though. Bonus points if you can get onto larger versions of Earth or Mars.)
* Take back off again without the need for dedicated launch support facilities (a clearing, road, or ordinary runway should suffice -- can't have a strongback/TEU or ground refurb facility in this application)
* Reach orbit without shedding large parts (leaving trash in other people's planetary space is rude, don't you think?)
* Maneuver on-orbit in an agile fashion (i.e. not limited to preset orbital parameters or automatic guidance)
* Operate without replenishment of consumables or refurbishment of the craft for 1 Earth week, minimum, including fuel/oxidizer/reaction mass and life-support consumables
* Provide for an operating crew as well as roughly a dozen passengers and their supplies or two tons of cargo, at a minimum (more is better)
The builders have:
* Ample supplies of materials that can withstand re-entry temperatures on Earthlike planets multiple times without refurbishment (or the worst case target planet if other than Earthlike)
* The ability to develop engines capable of equal or greater specific impulse and delta-V to the state of the art in current rocketry (nuclear-thermal and fusion-thermal are both explicitly on the table, but if they can do better, they will)
* A knowledge of structures, aerodynamics, and chemistry at least equal to ours, but still bounded by physical limits
* The ability to use the main engines to generate ample electric power (not hard)
The builders are also land-dwellers with the ability to dexterously manipulate fine controls and are on a human-scale (provided the life-support is compatible, a human could ride in, or even be trained to operate, this craft).
What design of craft would pop out of this?
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What is wrong with using a smaller version of whatever allows the main ship to maneuver? It likely has a propulsion system that allows it to roam around a solar system easily. It should be able to land and lift a vehicle.
If for some reason that sub-light drive cannot be used to land on a planet, try keeping a hot pile of some fissionable. Pour water on it and throw the steam out the thrusters. The steam would not be radioactive unless your system was very poorly designed.
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I'll address the propulsion in general terms.
Your requirement specifies high thrust. It also implies high specific impulse.(must be capable of SSTO, must presumably be able to do more things too than just barely make orbit) These factors together mean you need high power.
Chemical energy is too feeble, and since the craft needs to operate independently, beamed power is off the table. You're left with nuclear - fission, fusion or even antimatter. Now, there are concerns other than your ability to generate the required power and couple it to the ship without vaporizing it - past a certain point, your lander will be about as friendly to the region it lands on as a nuclear strike. I'm assuming your civilization is able to produce pretty much any sort of engine we've conceived of, but even then they need to make a compromise between performance and power just so they can land somewhere without utterly destroying the surroundings.
In particular I would suggest a [nuclear lightbulb](https://en.wikipedia.org/wiki/Nuclear_lightbulb). It's an advanced type of nuclear thermal rocket that's relatively "friendly" in that it doesn't contaminate the atmosphere with radiation and its wattage is modest enough that it won't turn everything into a glowing crater. Depending on just how optimistic you want to be about its thrust and isp, it should still be very capable of SSTO with propellant to spare. It may be designed to 'shift gears' such that it has a high thrust mode for landing and ascent and a low thrust, high efficiency mode for in space use. The craft will still be quite a dangerous thing - it doesn't leak radioactive material, but you don't want to be anywhere near it on the ground. Don't land right next to people people or they will be convulsing in radiation poisoning in short order. You'll need careful procedures for shutdown and getting on and off the ship, but these are solvable problems.
If you want the performance to just sort of effortlessly lift off from Earth, take a joyride to Mars, perhaps land there and just sort of cruise around all over the place without a refuel, the energy your craft must put out will start looking like a minor nuclear exchange. In principle, there is no reason something like [Project Orion](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)) couldn't be used for this. Perhaps your civilization wouldn't use something as crude as nuclear bombs, but some sort of nuclear pulse drive, perhaps ignited with magnetic fields or antimatter, seems likely. Any way you slice it, you need similarly huge amounts of energy anyway, so if you land on a road there won't be a road anymore afterwards. You'll have to be careful not to fry half the satellites on Earth orbit and to take care where you land, because you'll kill anything nearby and the engine's shine will burn everyone's retinas from tens of kilometers out. You'll contaminate the atmosphere enough that people might be irate. Not likely enough to actually kill or injure anyone though, as long as they're nowhere near when you come in.
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**Material shuttlecraft have repeatedly proven to be problematic{1}, so moving, projected force fields are now more typical for ground-to-orbit trips.**
After repeated close calls with transporter beams, most advanced galactic races now use force-field bubbles, powered and controlled from orbiting ships. Although the energy cost is enormous, it is short-lived, and eliminating the shuttlecraft, bay, hatches and maintenance gear leaves more in-hull space for replacement DiLithium crystals.
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{1} Federation and even Klingon case studies (at least those declassified to date) and historical analysis show a shockingly high rate of (matter-based) shuttle-craft accidents and total losses -- *almost* as if they were written as plot devices in cheesy SF series....
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Rocket propulsion, even funky [beamed-cored antimatter](https://en.wikipedia.org/wiki/Antimatter_rocket#Pure_antimatter_rocket:_direct_use_of_reaction_products) engines, are *so* last ice-age. They all use an *insane* power source, dangerous and unstable, to push a small mass really really fast and let conservation of momentum take care of the rest.
Instead, all the cool species have switched to using force-fields. The early models were simple electromagnetic devices that pushed against a planetary magnetic field, but that doesn't work on places like Mars. The new models are still electromagnetic in nature, but take advantage of *quantum shenanigans* to create a field which pushes against *every atom of the planet*. Instead of a small mass being pushed really hard, it is a large mass which is being pushed very gently. The result is the shuttle craft only needs to supply its own final kinetic energy, not lift its own reaction mass as a conventional rocket must, and even then it only needs energy as fast as it rises through the gravity well: with this drive, you could take off with only the solar panels covering the hull, provided you didn't mind it taking a week to reach orbit (something a conventional rocket could *never* do because of [gravity losses](https://en.wikipedia.org/wiki/Gravity_drag)). Neither do you need to worry about re-entry, because the drive can easily work in reverse and slow you down before the shuttle's hull touches the thicker layers of atmosphere at the high speed that causes all the problems.
But what if you want to do take-off and landing in a hurry, instead of a week? Perhaps a storm is coming your way? That's alright, just as electric cars use [regenerative braking](https://en.wikipedia.org/wiki/Regenerative_brake) to recharge their batteries while slowing down, so to does your shuttle. The energy levels are far too large for a conventional battery, so instead the shuttle pumps the excess energy into a tiny lump — 47g per tonne of shuttle mass — of [178m2Hf](https://en.wikipedia.org/wiki/Induced_gamma_emission): a relatively safe half-way-house between a nuclear laser and a nuclear battery. (Safe enough to keep around, so why not use it as a nuclear rocket? Because when it discharges it only emits gamma radiation, and while you can shield against that without difficulty, gamma radiation is *the worst* exhaust to use for a rocket if you care about saving energy).
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Not to go all steampunk on you, but the best interface vehicle for visiting disparate worlds with variant weather and negligible ground support is...
a tethered bathysphere.
Have your ship enter a low geosynchronous orbit then detach the bell and lower it down to the surface. The electrical and life support needs of the crew can be piped down through tubes in the tether, with on-board reserves of both to handle short term disconnects. Descent and return ascent are handled by winches on the orbiting vessel, saving most of the bathysphere's excess carrying capacity for shielding.
The vehicle could also be equipped with orbit-capable rockets which in case of a tether disconnect can carry one end of a strong thin cable up to the orbiting vessel. That cable can then be used to drag a new tether down into the planet's gravity well and guide it to the otherwise stranded bathysphere.
It is a low tech solution to a deceptively difficult engineering challenge.
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Look at the good old ships exploring the ocean in the past centuries for a reference.
They used the mother ship to explore the seas surrounding a new found land, but to explore the land they used smaller boats.
Reasons:
1. you don't risk your only ship by venturing in unexplored waters
2. you are more agile if you need to escape sudden dangers
3. you don't risk your entire crew on unexplored lands
If you put it into space, you also add the need for having to escape the gravity well with a flabbergasting huge and massive ship, which will cost a hell of fuel. Plus, designing your ship to withstand gravity will add additional weight to it, which is unwanted in space navigation.
Therefore they can use a reusable rocket (no nuclear engine, if you are concernced about leaving back a empty module I assume you don't want to leave back radioactive garbage, too) to land and take off from the planet, and the rocket thrust will put a limit on the maximum gravity they can afford to escape and the maximum load they can carry on returning exploration (*"that cow is a nice souvenir, honey, but it weight more than the 50 kg allowance we have"*).
Once on the planet they can choose to use lightweight
* wheeled rovers (for solid surfaces exploration)
* jet propelled ships (for liquid surfaces exploration)
* manned drones (for air exploration)
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I would suggest a hybrid antimatter driven system:
The shuttlecraft takes a form of a simple, not too high tubular rocket with retractable landing legs. Depending on the atmospheric properties, it either lands with parachutes, or powers up it's engines before touchdown.
It's liftoff engines are antimatter solid core units:
<http://www.projectrho.com/public_html/rocket/enginelist.php#amsolid>
These are lightweight, high-thrust engines, being simple and clean, and not putting out anything but hydrogen, and only a small amount of promt radiation. They require minuscule amounts of antimatter fuel. Their specific impulse is moderate, which means, that, in order to make LEO with a 10 ton spacecraft, they would need 15 tons of liquid hydrogen. But the shuttle only carries 6 ton propellant. This (4700 m/s of dV) is enough to secure powered touchdown, and shot the shuttlecraft again on a sub-orbital spacejump. After they are in space, they rechannel their antimatter into a small gas/plasma/beam core antimatter engine. (The exact solution depends on, how good they are with superconducting magnets and lightweight gamma shields. If not too good, they chose gas core, and carry more hydrogen, if very advanced, they invest into shield, and use a beam core with astronomical Isp. ) It's thrust is low, but they have time to make orbit and manouver to rendezvous.
Of course, generating and storing antimatter is a hard task, but since they have achieved manned interstellar spaceflight, they need to have at least fusion energy source, which means, that they are experts in magnetic containment, and have enormous energies at hand on the mothership. To survive interstellar trip, they would need lightweight radiation shields too, which are handy, if you are using AM rocket.
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How do you cut through an unbreakable armor? With an all-powerful sword, of course. No really, if we had seemingly unbreakable matter (lets give it the original name of Unobtadamentium, or Uium for short), could we process it with, say, tiny black holes as cutters and tiny white holes as hammers/anvils?
I'm writing a shorty on a typical long-time-ago-galaxy-far-away war, where good-guy and his nemesis must join together to find a way to process Unobtadamentivaibranium - the nigh-indestructible material from which apparently invincible armor and shields - as well as all those wbuilding.stack questions about them - are made.
There are ancient alien structures around the galaxy that were (even longer-time-ago, possibly in a galaxy-farther-away) made from this mysterious Unobtadamentireallystrongium, but no man made tool can shape the material, no man made weapon can even damage it. The powers that be figure that they can make near-invincible space ships, if they can reshape the stuff into such.
I looked at [Micro black holes](http://www.sciencealert.com/countless-tiny-black-holes-may-be-hurtling-through-space-like-bullets), and [White holes](https://en.wikipedia.org/wiki/White_hole) and I wonder if they're good candidates for the apparatus to create Uium in the first place, by placing a set of holes on various sides of some material, and using the gravitational push and pull to cram as much density as possible into one point in space. If so, they can be used to reshape Uium, in a similair way.
Assuming white holes exist, and that the apparatus doesn't slip from softish science into fantasy (I know, I know), I'm thinking:
* Micro black holes, each with the mass of our earth's moon, [smaller than the size of the dot at the end of this sentence](http://www.sciencealert.com/countless-tiny-black-holes-may-be-hurtling-through-space-like-bullets).
* Micro white holes, each with an anti-mass (and resulting grav push) of the moon.
* Uium must be dense enough to withstand a hundred consecutive modern nuclear strikes. It's what comes up in my mind as a good measure for "nigh-indestructible" and "no man made weapon can even damage it". If you have better ideas I'd love to hear them, but bear in mind that sending the stuff into the sun, or striking it with a bazillion gazillion nukes, is not practical. Uium must have some breaking point for it to be processed, but not a crazy overkill (just some general relativity tweaking..)
**My question is: What would be a viable black or white hole density to Uium density ratio (or in other words, what density can I set for Uium)?**
**Edit:** The guys aren't able to create black holes, I'll decide later on how much they're capable of getting their hands on such and manipulate them. Might decide that they only find the documentation on the ancient aliens' methods of dealing with Uium but sigh in despair upon realizing that these methods are beyond current human tech.
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Density isn't the main thing to consider here. Take gold, for example. It's pretty stable atomically speaking, it hugely dense, but you can bend it with your fingers and burn through it with a blowtorch. Even Tungsten, which is dense, tough and incredibly heat resistant, can be cut with acid.
Your unobtanium had properties that go beyond being dense. If it's 'indestructibility' is a plot point of yours then the methods for manipulating it are also plot points of yours. Science won't really help you here.
The material that you're suggesting sounds a lot like a super-stable form of degenerate matter, in which case manipulation of gravitational fields sounds like a good way to go and the densities that you're looking for are in the same range as [Neutron stars](https://en.wikipedia.org/wiki/Neutron_star) (3.7×1017 to 5.9×1017 kg/m3), but the exact configuration of the matter is exotic and somehow prevents [neutron degeneracy pressure](https://en.wikipedia.org/wiki/Degenerate_matter#Neutron_degeneracy) from blowing it apart again, as well as giving it other 'indestructible' properties that you can decide on later (reducing it's gravitational pull might be good unless you want people being torn apart by tidal effects whenever they get close to it).
I will say though that you've already set the bar for 'crazy overkill' pretty high when you posited that these people are capable of creating and manipulating lunar mass black holes. These guys seemingly have control over the laws of space and time, materials engineering really isn't going to be too much of an issue for them. If they want to create a gravitational field capable of battering matter into an exotic degenerate state I'd say they can just do that rather than first creating a gravitational field capable of battering matter into not one but two different types of singularity, then somehow manipulating that to batter matter into an exotic degenerate state.
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My main question is, how plausible is this on Greece's side?
The alternate-history world is set in present day. But during Greece's bankruptcy, they decided to sell of relatively uninhabited pieces of the country to outside powers. They would give water rights and land to the buyers and have no government control except of the borders. I don't know what it would take politically to make this happen, a vote? a treaty? But I'm going to say they peacefully accomplished this and did a good job at accommodating locals who lost land and water. They got a super duper deal.
Interested buyers organize micro-states with their own governments (or lack of governments). Putting this into an alternate history would have its problems, but I that's on purpose, that's what my project is all about. My project will be to gather people's imagined lives as pioneers and immigrants to the micro-states.
So on the Greek side (and any party who might feel like they have a say ahead of Greece, like European Union or UN) what holes are there?
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This is possible, but probably not with the consequences you imagine.
Being able to buy a foothold in Europe would make various governments salivate. Russia and China would be intensely interested, and for all I know North Korea, ISIS/Daesh, and Al Quaeda would jump on the bandwagon.
Your concept of "no government control except of the borders" just doesn't work. Either a nation controls its territory or it doesn't. For example, if a tenant smuggles a nuke onto his plot, or starts working on bioweapons, will Greece sit idly by? Not hardly. In fact, if the territory remains Greek, Greek laws are going to apply, and any prospective tenant must understand that the policy of "hands off the micro-state" is only guaranteed to be good until the next election, or a public outcry about the uses to which the land is being put - whichever comes first. If the tenant is allowed to develop a micro-state, and the status is not a sham, then the micro-state must have sovreignity. While this may seem pretty innocuous, since any private group won't have the military muscle to butt heads with the Greek army, there is nothing to prevent the micro-state from making an alliance with a big brother (such as Russia), and then the situation gets murky and uncomfortable real fast. Of course, various groups would bankroll straw buyers who would immediately declare for their sugar daddies, although this would have the immediate benefit of driving the bidding up to stratospheric levels in short order.
As for the question of local inhabitants, I don't know Greek law well enough to declare this with certainty, but certainly in the US the doctrine of eminent domain would allow the locals to be moved off the land with a "fair market value" payment and no legal recourse. See particularly [Kelo v. City of New London](https://en.wikipedia.org/wiki/Kelo_v._City_of_New_London). I suspect Greece has something similar.
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# Could not happen because most of Greece is inhabited
Greece is part of the European Union, and the European Union is democratic. One of the principles of democracy is self-determination.
There are not a lot of parts of Greece that are not inhabited or utilized by some Greeks. For example, [all of these islands](https://en.wikipedia.org/wiki/List_of_islands_of_Greece) on the list of Greece's largest islands are inhabited. That goes down to about 90 km$^2$.
Uninhabited islands look like [this](https://en.wikipedia.org/wiki/Agios_Georgios_(island)) or [this](https://en.wikipedia.org/wiki/Psathoura). Even tiny islands like [this](https://en.wikipedia.org/wiki/Piperi_(Greece)) or [this](https://en.wikipedia.org/wiki/Marathos_Island), down to as small as 1 km$^2$ have people, even if it is only 5 or 6 of them. For the uninhabited islands, their marine waters are surely someone's fishing grounds.
Greece can't give away those lands without consulting the people living in them, or the people who fish them (or move their goats and sheep there for grazing, another way that some empty islands are moved). If they did give these lands away they would be condemned by the EU, and more importantly, condemned by their own citizens.
It would not happen.
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One of the issues with real estate investing (since this is essentially what the Greek government is trying to do) is the mantra of "location, location, location!
The Greeks want to get top dollar for their land so they can pay off billions of Euros of crippling debt, but as a buyer, I'm going to want a reason to *pay* top dollar, and vacant farmland in Thessaly isn't going to cut it. I would be willing to put in a bid for the Acropolis, some great beachfront property on the island of Mykonos (oh hell, the entire island) and maybe Arcadia, so I can grow grapes to take on my picnics at the Acropolis. Most other buyers are going to be thinking along the same lines, so the Greeks could be paying off their debt by selling Mount Olympus and other high value properties, much like Monopoly players can mortgage properties to stay in the game.
[](https://i.stack.imgur.com/F3E55.jpg)
*What do you mean, the Reading Railroad. I distinctly said Mount Olympus!*
Ownership comes with privileges, like being able to do things to increase the value of your possessions, transfer ownership to others (I sell the island of Mykonos to you so I can afford some more classical Greek temples on the mainland) and so on.
The other issue for the Greeks (besides their new landlords jacking up the rent or simply kicking them off the land) is the Greek Government is going to find the property owners are not just going to sit still to be milked by the Greek tax system. Anyone who goes into a land auction under these circumstances know they have the Greek government over a barrel, and can insist on clauses like having a 99 year tax holiday, only be subject to the laws and customs of the owner's home territory (this could be hilarious in the case of the Brexit, as British land owners impose British rules on their property rather than Greek or EU ones) and so on. The Greek government will also be either subtly or forcefully reminded that these people are rich and powerful in their own right, and certainly going to be more than willing to defend their own interests. Londoners who have encountered the retinues of wealthy Arabs from the Gulf States will certainly understand the sorts of behaviours I am talking about.
This could be played out as a comedy, but since the Greek government is essentially selling its Sovereignty it is really more of a tragedy. Simply defaulting on their bonds and being cut out of the international credit market will probably be equally painful, but have fewer deleterious effects on the average Greek citizen.
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I'm currently working on a story treatment for a monster story. The story is sort of a love letter to many different genres and classic tropes employed and made famous by, John Carpenter, Ridley Scott, David Cronenberg, and George Romero. With a heavy dose of Ishiro Honda's early work with Tokusatsu films, such as the original Godzilla.
I'll try to do a quick rundown that will hopefully shed light on the main antagonist of the story, The Magdalene. The creature is a large amphibious monster that can best be described as a 150 foot long Salamander who's body seems to be composed entirely of horrific cancerous tumors, and suffering from a full body bruise, as its skin is sickly and black looking.
The creature started out as a collection of micro organisms made from cancer cells, and originally conceived by a multinational research project in hopes of creating a cure for cancer. How this works is simple...sort of.
1. First the Magdalene are injected directly into the patients body.
2. The Magdalene will then congregate on the cancerous region and began to devour the cancerous cells, and then die shortly after.
The problem is Magdalene batch #001 is ineffective in long term treatment, as they tend to die too quickly to successfully kill the cancer, batch #002 was developed to be longer living and more aggressive and was created using the rare mutated cancer cells of the main researchers deceased former colleague, and wife. Her last wish was for her body be used for scientific research that may one day make the world a better place.
This new Magdalene variant was hyper aggressive and was designed with a genetic kill switch that would activate in case the organisms ate more than what was intended. However over time batch #002 evolved and mutated, figuring out a way around the kill switch, leading to them going out of control, multiplying and absorbing bio matter at a ravenous rate.
Now that we know exactly what they are, lets break down their life cycle and how this colony eventually evolves into the larger forms.
1. The Magdalene begin to multiply and spread the already existing cancer throughout the victims body, causing them to grow large horrific tumors all over their bodies, which the Magdalene will then feed on and grow. Overtime they completely replace the victims cells with the aberration Magdalene cells.
2. The infected hosts are taken control by a specially evolved Magdalene type that acts in a similar way the Ophiocordyceps unilateralis fungus does with carpenter ants, manipulating the victims bodily functions to use as a platform to which they can use to consume more bio-matter.
3. After a suitable amount of bio-matter has been consumed and integrated into the hosts, they will eventually converge on each other and merge together on the cellular level, creating a gargantuan gestalt organism that has a Deadpool-esque healing factor based on the fact it's a waking cancer beast.
Several of these gestalt forms are birthed, three to be exact. One that develops in the sea and becomes a 70 foot sea monster, the original locked deep within the original research facility that gave birth to the Magdalene, and one created by infecting the town adjacent the facility. These eventually merge together into the final beast; a 150 foot long salamander-esque monstrosity.
The story and processes behind all this still need s few kinks worked out, and the science is more than likely unsound, but when I originally envisioned the story I wanted to create a type realistic and hard science take on Kaiju and giant monsters, which leads to the main questions.
1. How sound (or unsound) is the science behind what I'm purposing here?
2. What exactly can I do add some verisimilitude to the story and concept?
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There are limits to what speculative biology can deliver. Looking at steps 1 to 3 in your proposed colony development and how it turns into a gigantic form, there are frankly too many things that have to come together and work to create a viable giant monster and do it successfully.
While this is the kind of pseudoscientific nonsense that passes for science in many science fiction movies it doesn't stand scrutiny. It would be better if you went back to first principles and designed a better giant monster. Your approach to create a Kaiju giant monster that was based on realistic science is to be applauded.
Instead of starting with a cancer cure gone wrong, let's use a gimmick from one of the creators you are saluting with this love letter. I refer to John Carpenter. Let's assume that a fragment of an unknown alien organism has been discovered. A research facility is doing work on this sample and when its cells become integrated with other tissues the alien genome activates and creates a range of different horrifying monstrosities. Think the *Thing*, think Cronenberg's fleshy horrors *various films*, Romero-like zombies can be spawned when alien cells infuse the bodies of victims killed by other stages of this multi-metamorphic monster, and Ridley Scott's *Alien*. Finally the alien organism merges with a lizard and this hypertrophies into a Godzilla-type Kaiju monster.
Essentially assume there is an alien metamorphic super-organism capable of taking over the genomes and biology of other organisms which can be everything from tissue cultures, lab animals, research staff, domestic animals and plants, passing lizards or marine creatures, and let's not forget birds (there's no reason why you can't add an Alfred Hitchcock tribute too -- unless you're not a fan of Hitchcock). The original alien organism would be a super-effective shape-changer that is capable of hi-jacking other creatures and transforming them completely into effectively whatever it wants, which usually means some kind of a monster.
You can choose your monsters from the suite of horrors that John Carpenter, Ridley Scott, David Cronenberg, and George Romero have given us. These are only suggestions. best if you use them as a starting point and go from there. Have fun!
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Randall Munroe humorously proclaims that he'd want to live in an example map in a geography book;
[](https://i.stack.imgur.com/aazts.png)
That means that the geography varies *wildly* in a small area.
Assuming the following:
* This is on Earth or an Earth-like planet.
* For the sake of this question, use the exact map above, including the location of the house.
* The map is to scale (i.e. even though there's no explicit scale, the implicit one is consistent).
**My question is threefold;**
* How could an area with this geography come to exist?
+ Preferably naturally, but artificially is OK.
* Can this area be stable? For example, will a flood irreparably change the landscape?
* Would the area marked "my house" be livable, assuming it's self-sufficient or able to access a nearby town?
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I see a problem having a mesa that close to a volcano. Dropping a volcano requirement, take a look at [Santa Marta, Columbia](https://en.wikipedia.org/wiki/Santa_Marta#/media/File:Sierra_Nevada_de_Santa_Marta_desde_el_espacio.jpg). It is not clear at the satellite view, but the area right East (and in the rain shadow of) Santa Marta mountain is a Guajira desert.
Totally natural, and AFAIK perfectly stable for at least few millennia.
And yes, I'd love to have my house there.
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I'm not so sure about how such an area could come into existence. But I can offer my thoughts regarding its stability.
Being on a flat plain among rivers and deltas, with hills on one side and mountains on the other side, I can see what would be worrying me. Water!
I'm going to assume since there is a desert to the west and a forest to the south that the whole area is low on rainfall, it's rare to see rainfall change so drastically in a small area so the existence of the forest must be explained by water, either from a strong tide or the melting of the glacier. In either case, the water has only two places to go, the forest, and the plains where your house is.
I strongly recommend gathering some wood and either building a tree house or a boat, and best make it quick! I don't like the ominous stare of that nearby volcano, it's obviously not erupted in a while, otherwise the forest would have been badly damaged, and it looks pretty active, so is probably due a big one soon!
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Now I know that steampunk is generally done in around/past the industrial revolution (and that what I'm lookong to do may not technically even be steampunk), and for good reason. However I'm looking to build a world where a great calamity has struck an advanced civilization, throwing its people back into an era more akin to the medieval times. That being said, traces if this civilization still exist, and people have both learned from it and used the parts to build their own technology. The question is what would that technology look like? I'm thinking still early in the dark era, so they still wouldn't understand most of it and would not have the tools to create any of the finer pieces. But how would the presence of this ancient technology affect the tech growth of the current people?
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You are right that this isn't steampunk, it's certainly an interesting world-building possibility though.
This is something that has been looked at numerous times throughout fiction and RPGs so you can certainly find elements for inspiration in all sorts of places. For example Numenera, Babylon 5, Against a Dark Background, even Fallout.
At least initially the famous Arthur C. Clarke quote would apply *"Any sufficiently advanced technology is indistinguishable from magic"*.
The wizards of the time would use the scraps of technology without understand. The mystic incantation "ok google" that activates the demon in the box. Some technology would reveal itself more easily, anything mechanical in particular can at least be understood if not duplicated.
The existence of scientific records, or scraps of them, would allow faster progress in many areas - but so much of what is described would be meaningless without the context to back it up.
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I think Asimov's *Foundation* "trilogy" might give a rough idea of this:
In that series, as humanity declines back to the dark ages on hundreds of worlds, the operation of advanced technology becomes like a religion-- people know how to *use* technology, not how the technology *works*.
For example, they might know that they can light up all the buildings in a city by performing a certain ritual before the "Djinn Erraytor"...but they don't know that pressing a certain button primes a pump, or adjusting a dial until a needle falls within a certain threshold will set control-rod depth and to prevent a meltdown.
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We have a real-life analogy for this: The fall of Rome. People lost the ability to build things like the Romans had built, but they could see the decaying artifacts all around them. Monks preserved the old knowledge until people were able to rebuild the economic base to use it again.
The result was that people had great respect for the abilities of the ancient Romans for centuries afterward. Even after they surpassed the Romans they still seemed to have an exagerrated respect for them. But no one seems to have thought their technology was magic or incomprehensible. There was a very sensible attitude of, "We need to study these ancient books and learn to reproduce what they did, and figure out how they were able to do things that we can't."
Enclaves could maintain some technology. Like, I think a small group could build a hydroelectric generator to produce electricity, make light bulbs and other simple electrical devices, and maintain a 19th century technology. But some things require a huge technological base. I have a hard time imagining a few dozen or a few hundred people getting together, reading old books, and building a nuclear power plant or a microchip manufacturing plant. Some things just require too many specialists with diverse knowledge, and too many components that are presently made by different people all over the world.
Clearly something like "building a cell phone network" requires the involvement of very large numbers of people over a large area. Even if you they are able to build the phones and towers themselves, who's going to build and maintain all these towers, and all the lines to connect them?
Some technology could be kept running but would not be replaceable when it broke down. Like if someone did make a small electric generator, he could plug in a computer and use it, but once that computer broke, he'd be unlikely to be able to repair it. Like the old Roman roads and bridges, they could be used until they wore out or collapsed. Or like the Colliseum ended up being used as a zoo and finally a garbage dump.
As people rebuilt, progress from medieval technology to modern technology would be much faster than it was the first time, because they don't have to reinvent everything. They have the old records to give them a shortcut.
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You might want to read "1632" and" "1633", the first books in a time travel series, as your question is very thoroughly explored by the authors, and ditto with the associated "Grantville Gazette", at least the first volume if not others.
Basically, there are two variables here:
1. How long is the period between the fall, and when a stable enough society (even a small one) emerges from the chaos, with the ability and the will to rebuild?
2. Is the interregnum long enough for all books to have vanished, or are they still around?
It's been pointed out that all you need is a set of the Encyclopedia Britannica circa 1880, and you can reconstruct steam-era tech. That should be self-sustaining even with a relatively small group... say, a small city or several cooperating villages in close proximity, with a total population of 2000 or more.
Electricity, as Jay suggested? Well, if you can make wire -- and heck, you can do that even with medieval tech -- and have the instructions for making an electric motor or generator, then certainly they can generate electricity. But what are they gonna do with it? Making light bulbs is much, much more difficult, and mass producing them is a very specialized industry that isn't likely to arise very soon. Both mass producing light bulbs, and building an electrical distribution system to send power to factories and homes, both imply a highly organized, large society... which isn't going to emerge for some time, given your scenario.
If it was me, I'd go with Watt (reciprocating beam) steam engines (not later, more efficient and more advanced steam engines) used as stationary power generators for industry, and gaslights. Since you used the term "steampunk" in your question, hopefully that will fit right into what you're looking for. And keep in mind that there were steam engines around a long time before railroads, which evolved from tramways using wooden rails; and it was a long time before steam engines could propel ships across the ocean. Think early steam age, not late. Think canals and tramways with horses or mules as the motive power, not railroads. That tech would be a lot easier to build and maintain without a large population base, and without thousands of mechanically skilled, trained workers.
The biggest obstacle to rapidly advancing tech is going to be lack of machine tools. When Watt made his first steam engine, the state of the art of boring out a metal cylinder was so poor that he could fit a shilling between the piston and cylinder! You need the tools to make the tools to make the tools... and they just don't have the tools to make precision metal-working tools. Most or all of those will rust away long before the books turn to dust. Even with instructions for making advanced, more efficient steam engines -- or even more advanced machines -- they won't be able to make them. Significant advancement towards a higher tech level would require an industrial base formed from a sizable, and at least semi-educated, population base. Something on the order of at least hundreds of thousands, and more likely millions, all working under the same government.
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I think a lot of different factors are to be taken into account here.
# Do they speak a similar language ?
There are printed versions of Wikipedia. Books, encyclopedias, anything.
If there is leftover tech, there is leftover books, and those would be huge.
Note that there is no need for a lot of books: the first group of men to control a university's library will just rule the surroundings, able to get back to a perfectly normal level in less than a century (total guess from me though)
So, next, I will imagine that all libraries were lost and/or that no one knows how to read. Eventually though, that knowledge will be back.
# The technological difference
A caveman, seeing a car, will not think "I could drive that". At best, it would use it as a house. Depending on the technological regression, that kind of thing could happen for most objects.
If the difference is small, they will be able to retro-engineer stuff and science will get a big boost. If not, technological objects will be seen as "mostly the materials they contain". Metal is always valuable, and if salvaging stuff on the ground costs less than digging down for it, salvaging will happen.
Of course, a minority will say that those objects should be studied or that "it belongs in a museum", but most people will be busy making their immediate life sustainable in a post-apocalyptic mayhem.
# The maintenance problem
Most technological devices require maintenance and/or an energy source. Technology doesn't work just because it's here. It works because we're here to make it work and we know how. Producing batteries, operating powerplants, repairing broken stuff, that's impossible to do without knowledge.
This would probably add to the fact that they would not understand anything about the technology they're handling: imagine you don't know what a car is, you don't have a the car key, or gas, or a new battery and the car's computer system is down. From the wheels, you can understand that it's a vehicle, and where the driver should sit, but there is no way you can start the car, or understand the engine. Most likely, you would look for a way to put a harness on it.
# So would it have an impact at all?
My guess is, most people would fight for the buildings and materials, without trying to understand the tech itself.
People in power though, would keep stuff intact and pretend to understand it for fame. And a man influential enough would pay for research until they manage to find books and read it.
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Well, the internet was supposed to survive that sort of calamity. Let's just say that somehow the transmission lines for the net remained intact, and that at this advanced stage of civilization the power for the internet had somehow been taken off any notion of a grid, and ran on like a source of perpetual energy, or something mooched from the environment -- in that case, even damage to most of the nervous system of the net would still leave operating circuits. Most probably, at such an advanced stage civilization, devices something like iPhones were widespread, and the notion of IoT and interoperability of component parts also so, so there could be a diverse array of "found" devices, which can still plug into the remnants of the great global web. Of course...hackers, bitcoin, BBS, other things can still exist because of this information backbone that remains. If you consider that, in essence, life is an "information technology" and it is something capable of persisting by being self-sustaining with respect to resources in the environment, I think a slightly more developed iteration of our internet, which can somehow become self-sustaining off the resources of our environment, is the most likely type of technology to survive myriad calamities across the greatest number of possible worlds.
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For the first while (perhaps several centuries past the apocalypse world), you would not have a "steampunk" universe, but rather a "scavengerpunk" universe.
In previous "dark ages", people may have thought of the structures and temples of the past as mysterious relics (the Ancient Greeks evidently thought the Palace structure of the Mycenaean civilization as being built by the Cyclops), but generally "free game" to be repurposed as building materials for walls, rubble for road building or metal parts melted down for more immediate uses.
In your more enlightened age, people will be scavenging cities for abundant metals, and dismantling machinery for usable parts. There could be a whole "hillbilly" tech of repurposing parts to keep old cars and trucks going, pulling apart devices for pipes to make stills (for alcohol fuel and "medicinal" purposes), presses for reloading firearms ammunition and so on. Electronics will be much more difficult without the infrastructure for testing and manufacturing, and many electronic devices will be "killed" because there is no "clean" source of electrical energy (a voltage spike from a defective windmill or bicycle generator will do in a computer, for example). The movies "Mad Max" and "The Road Warrior" show a society degenerating to these levels as oil becomes scarce to non-existent, so this is a good place to guide your thinking.
Several answers have suggested that books will be important, which is true to a certain extent, but unless you have salvaged detailed technical manuals, it will be difficult to keep things in running order. Don't forget that the infrastructure to make all the parts and tools is gone, so until you either scavenge the part, repurpose something different to work or make the tools to make the tools to build the part, you could be stuck with dead pieces of machinery, engines etc.
In the end, people will be heavily influenced by the mechanical artefacts from the past age, simply because they are understandable and can be passed down through the years with maintenance and close observation. Electronics, especially solid state electronics, will become a lost art, simply because there will be no way to repair, maintain or make new examples, and electronics will have to be rediscovered at a later date.
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Stars and constellations have been for many civilizations,sources of wonder and mystery. We look at the stars so much, that we found patterns and shapes in the stars, and used them as guidance during sea exploration. Even today, universal laws and theoretical physics still stem from the stars. However, what if we never had the stars?
How would a civilization similar to earth develop, if at night, no stars were visible to the naked eye? You could still find stars if you had a powerful enough telescope, but for pre-telescopic history, the only visible thing in the night sky would be the moon.
What about our culture could be different, and how would our physics and math develop differently?
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Questions like these are tricky. If you say how things could work, you imply how they could not. Cultures evolve in myriad ways, I hate to limit them with a few quick strokes of the brush (or, in this case, the keyboard). However, there are a few things that may come of it. The most prominent is that the stars are a natural source for the concept of infinity, or at least "farther than anyone can reach." Another facet is that they are a remarkable symbol of stability. Everything else may rotate freely, but it does not take long to realize that all of the stars move as one across the night sky. Lacking this, a culture might evolve a more fluid understanding of physics and math which is less focused on how to pin everything down.
Beyond that, the sky is the limit, really.
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I'm analysing this as in the technological aspects. You could of course say there'd be no astronomy, leading to no exact calendar, which would mean living day by day. Sailing wouldn't evolve. No ships, no transcontinental trips (or at least very few successful), no military fleet, no earth coordinates, we would maybe still think the earth is flat and we're alone in the universe, leading to no possible invention of satellites, advanced maps, coordinates, no man in space nor on the moon, no understanding of gravity force at long distances and its difference compared to other elementary distance forces; I believe we'd live in a primitive egocentric wild society, living day for day with the sole thoughts of eat survive reproduce and kill or be killed. Think about how much seeing the stars helped us...
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This question is a subsidiary of: [Shapeshifters - Shared language between human and animal forms](https://worldbuilding.stackexchange.com/questions/35560/shapeshifters-shared-language-between-human-and-animal-forms)
There is some of background information in that question, but none of it is critical for this question.
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Human languages with as few as 10 phonemes [exist](https://linguistics.stackexchange.com/questions/4561/languages-with-the-fewest-phonemes).
With this in mind, is there sufficient overlap between the vocal range between wolves and humans to construct a shared language with at least 10 phonemes?
For the purposes of this question, assume the wolves have human-level intelligence.
(*Note: I am also interested in the same question with respect to humans and other mid-size mammals, but am sticking to wolves for now for simplicity. If you happen to have relevant information for other species feel free to share it in the comments or as a footnote to your answer*)
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I had to think about this one because I wanted to find a way to make it work, but I don't think there is a way to accomplish what you are looking for, at least, *not in the way you are thinking*.
**Having two different species that are that different converse in what we consider a language just isn't possible, though it would admittedly be cool if you could.**
I think I have a suggestion if you are willing to adjust your view just a little bit though.
You are approaching this question from two separate perspectives. A wolf perspective and a human perspective.
In the case of your story though these polymorphs would naturally blend their two forms. If they move in and out of their forms regularly from an early age they would be just as comfortable in either skin, so to speak. The point here is that **they are not** *humans that turn into wolves* **nor are they** *wolves that can turn into humans*. If they are true hybrids and live in both worlds communication between members of the tribe would, by necessity, have to be developed naturally. It would be both wolf and word and probably significantly weighted toward communication methods both can use, mainly sight, touch, gestures.
So I guess I am saying that a hunting or war party from your wolf tribe, not to mention those going about their daily life in the camp/village, would naturally develop a way to communicate with either form and the combination of all those verbal and non-verbal methods could be your *language*.
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I don't think this can happen. For one thing a wolf has a higher range than a human so the speech would be uncomfortably high for humans and low for wolves. This would over the long term damage the vocal cords. Also the wolves communicate through sign language/body language as much as any sounds. Humans would struggle to mimic this. The best you can get would be a hard to speak, primitive language. If however the wolves are intelligent you could consider a simple writing form based in straight lines. Humans could use writing to tell the wolves things and they could reply by drawing simple straight line characters, it would be slow and primitive but better than trying to talk.
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I was thinking of a sci-fi story where a large population of human beings (let's say anywhere between hundreds and millions) live on a planet with robot guardians. But after a certain amount of time living in isolation from the rest of humanity, their genetic code changes enough that their DNA is no longer marked as *homo sapiens* by the computers. The machines turn on them, having been programmed to protect their human wards from potential "alien species."
How many years would the human colony have to be on the planet for that twist to be plausible?
Side question: If I made the planet more radioactive, could I plausibly speed up the evolutionary process in a way that wouldn't horribly scar the actual people? If not, is there another way to speed up the process while keeping the community as close to human as possible?
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This depends on the population of the planet. There are several different views about how origin of new species occurs.
# Origin Of New Species: Method 1
Some scientists believe that:
* The process of evolution begins with a need for adaptation. There must either be some big incentive (a new food source which is not utilized by any other species etc) or a big threat (adapt to the new conditions ... or go extinct).
* The species goes through a general evolutionary phase. As in, several individuals go through different types of genetic changes, which continue to be mixed and matched as the individuals breed, forming more genetic variation in the next generation.
* Soon (in a few hundred thousand years), the environmental conditions decide which type of individuals are best suited in the changing world around them. These individuals proliferate while the others wean out and go extinct. In all of this process, a **group** of creatures evolve into another species.
Under this scheme of evolution, your humans would take at least several hundred thousand years to have a 0.1% DNA change that *could* mark them as a different species (depending on how the robots determine it). You would also need to provide the reason for change. Is the atmosphere slightly different than earth's and the respiratory system has to change a bit to adapt? Is the gravity of the planet slightly more or less than earth's and the bones of the people undergo a slight change? Are there new food sources (plants/animals) on the planet that require modified teeth/stomachs/intestines/kidneys?
# Origin Of New Species: Method 2
As much as I like the above mentioned theory of origin of new species, most scientists believe that origin of new species follows these steps instead:
* One individual in the population undergoes a random mutation. This mutation helps its offspring to be slightly superior to its competitors. It runs faster/its hearing is keener/its jaws are stronger etc.
* Due to more success than the other individuals of its kind, this individual has more chances of procreating, so with time the individuals of this type increase.
* With time, more random mutations occur and the same process goes on rinse-and-repeat lines.
In this scenario, you would have more trouble explaining why *all* of the population underwent the evolutionary change, as reproduction in humans is no longer a game of physical characteristics anymore.
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# My Recommendation
If I were the writer of this fiction, my story would follow these lines:
* The atmosphere of this planet has *slightly* lesser oxygen (~19.5% as compared to 21% on earth).
* People have slight difficulty in breathing, but it is mostly subconscious, they do not consciously notice that they are breathing slightly faster than humans on earth.
* Scientists invent a respiratory aid for people. People undergo a minor surgery which dilates their trachea and helps them inhale more air with each breath.
* A group of genetic scientists figure out a means to improve the tracheal and lung structure of the next generation so that they would not require any surgery at all. This would involve changing a set of 8 genes in the human DNA.
* The genetic change is applied at some test mice (imported from earth) and the results are satisfactory. A 3-day schedule is announced for this genetic change to be applied to all the people on the planet.
* The gene-changing machinery is very large and runs on a lot of power. Since the population of the planet is high (several billions) and the robot guards take a lot of energy to keep running, the defense mechanism is shut down for these 3 days so that there is no electric overload.
* All the people in the population (you might save some, the lazy ones like me who missed the schedule due to one reason or the other) go and get this change of genes.
* After the process is finished, the robotic defense mechanism is turned on, and voila ...!
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**Much faster than you might think. One generation!**
For this story, you'll have to dump those silly robots. Instead, imagine this. Some years in the future, doctors become aware that a rapidly increasing number of young couples are attending fertility clinics. Plenty of young couples are still giving birth to healthy babies, but far more than in previous generations, can't.
The penny drops. It is discovered that these couples are infertile because one of them has an odd number of chromosomes. He, or she, is sterile for the same reason that a mule is sterile. And of course, this means that part of humanity has evolved, un-noticed, very suddenly, into a new species with two more, or two less, chromosomes. You can't tell them apart, other than using a microscope to count chromosomes. Or more likely, you can *hardly* tell them apart. Once you know what you are looking for, you can tell, though with rather less than 100% reliability absent scientific confirmation.
Over to you, the author. I've no doubt that the new homo species will have inherited the same amount of bigotry and boneheaded stupidity as the original. It might be interesting to make the narrator or hero one of those sterile hybrid children.
OK, to the hard science. Consider the horse and the donkey. Two separate species sharing a common ancestor. Yet a donkey has 62 chromosomes, and a horse, 64. How can they share a common ancestor? How can any creature have a different number of chromosome pairs to its parent, and yet manage to breed non-sterile offspring?
If a single proto-donkey had once given birth to a single mutated foal with an extra chromosome pair, that would be a genetic dead end. The only way that foal could reproduce is if, in the same generation, a significant fraction of other proto-donkeys were also giving birth to proto-horses. To repeat: unless something triggers the same genetic repackaging in a significant percentage of a species *within the same generation*, a new species with one more or one fewer chromosome pairs cannot arise.
It is believed that a widespread virus or retrovirus infection is the probable triggering mechanism.
I've talked of horses and donkeys because mules are well-known. In many ways they are superior to both their parents. But they are sterile. Something similar must have happened in the very recent evolutionary history of *homo sapiens*. We have a different number of chromosome pairs to our nearest extant related species, the chimpanzee. The causative virus may still be out there. Or if it's a retrovirus, it may still be latent within us.
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Big initial population means low genetic drift. Go a lot smaller to start, or bottleneck the population at some point (massive planetary disaster, or biological problem).
Selection effects or environmental pressures could conceivably move things along (ie: omega-3 fatty acids in Inuit populations, lactose-tolerance in Europeans, etc).
And I'd suggest that robot guardians are the way forward. Have them select against the violent, the criminal and the insane... And all of a sudden pleasing robot guardians is a selective effect/environmental pressure on the population.... Irony express, here we come.
Radioactivity will increase cancers to start, and will probably just make more broken people. If the overlords didn't cull the humans when the first million were brought, then we've already got a ton of broken genes - a few more won't register with their filters (as they're already loose enough that all of those people qualified as 'human' to start).
Might be better if the robot's programming / reference sample were corrupted, hit by cosmic rays after the shielding got destroyed in the disaster (strike by extinction-level sized meteor - backups already lost due to criminally insane taking out a couple facilities)
The protection from alien species would probably result in the elimination of any mutants who didn't fit whatever the profile is, instead of the robots turning on the population as a whole - if you want to have the humans attempt to speciate, you're going to have to let mutants run rampant in the population, and out-breed the ones who do fit the human profile. Which means the robots have to do a pretty bad job for quite a long time before getting back to work.
400 is pretty much as low as you can go, and be viable, and will definitely have potential drift. However, that population needs to be kept small (think Darwinian small islands with open niches vs. continents). If you have explosive growth (16+ kids per family, say) because there are no natural limits; ie: it's a paradise, and everyone is living on the beach and fish are jumping into your hands.... then the drift doesn't happen, except if there's a 1/400 rare gene and that guy dies initially. It's when the population gets crunched that lines die out, and drift occurs.
Differences in these variables result in very different time-frames (if anything happens at all). We're also tool and culture using, which almost completely eliminates most selection from happening. How many people do you know who died in childhood, or were unable to breed?
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What is the definition of "homo sapiens"?
Would a chimp at a local zoo be targeted for elimination by the guardians? Any alien is going to be far more different than a chimp (or a cow, or a pig, or a chicken).
Babylon 5 had an episode that investigated a similar set up for a destroyed civilization. Soldiers had been created (using biotech on suitable individuals) and were programed to purge the impure from the population.
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**Retrovirus!**
A retro-virus inserts its DNA into the DNA of the host cell. Usually that is a regular somatic cell. However, it is theorized that retro-viruses can also insert their DNA into a gamete (sperm/egg) cell, and when that gamete creates an offspring, the virus' DNA is permanently incorporated into the somatic cells of the offspring. Then that offspring will create gametes with the virus' DNA and pass it on to the next generation!
Let's say a retro-virus infects a single sperm. That lucky sperm joins an egg and contributes its half of the DNA+virus DNA to the new baby. That half could have genetic dominant traits that cause enough changes to mark the baby as a new species. Now multiply that out:
For the population at large: you could have a highly contagious and infectious but harmless to the host retro-virus that attacks gametes both sperm and egg, thus making every baby diploid with the new DNA. (You might have to explain what effect the retro-virus has on such babies.) The new DNA should not be fatal, obviously, since you want the babies to be killed by the robots. How cruel you are!
But you're storyline has to wait a while. "Species" is often defined by being un/able to produce viable offspring. You'd probably have to wait till these babies reached sexual maturity to find out that they cannot reproduce with non-infected but can reproduce with other infected. (Unless you have a way to determine fertility or reproductive compatibility strictly through blood or DNA or other tests. I mean obviously after you discover the incompatibility issue then you can just screen for the new DNA. I'm just talking about the initial realization that the infected constitute a new species.)
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This question asks about traditional artificial wombs viability ([Is an artificial womb feasible?](https://worldbuilding.stackexchange.com/questions/24007/is-an-artificial-womb-feasible)). I was wondering if we could take an alternative route by using a biological womb instead.
Is it possible that we could utilize animals as surrogate wombs for humans? I know that currently we have found some species can act as surrogates for closely related species children, but the majority of the time a mother's body will reject most other embryos. However, in the future we will develop new techniques and tricks, and thus could theoretically work around existing problems.
Thus we get to my question. Is it possible in the somewhat near future to develop a technique to allow us to implant a human embryo within another species and have that creature carry the embryo to term. For now you can assume surrogate situations where the mother is not available to carry, an animal does not need to be a better surrogate then a human, just as viable (or even almost as viable) as a human surrogate for situations when no human is available to be a surrogate.
If it is viable I have a few follow up questions. First, is it possible to pick from a number of animals to be a surrogate? Will we be limited to only primates, or perhaps we would have to genetically manipulate (using *near* future technology, so genetic engineering is still limited and must be a comparatively easy change) the creature to accept human embryos?
Second, is it reasonable to believe that this approach could be an option prior to mechanical artificial wombs being developed, since there is no reason to go this route if we have viable artificial wombs to use.
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In theory there is no reason why this is not possible, in the same way that in theory there is nothing stopping a completely artificial womb being constructed.
There are definitely complications to this method and we are only just starting to learn ways to mitigate these complications:
From <https://en.wikipedia.org/wiki/Interspecific_pregnancy>:
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> For example, embryos of the species Spanish Ibex are aborted when inserted alone into the womb of a goat, but when introduced together with a goat embryo, they may develop to term.
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<http://media.longnow.org/files/2/REVIVE/THER1999%20Interspec.%20embr.%20transfer%20S.Ibex%20Dom.goat.pdf>
The fetus needs a specific mix of nutrients, environment and stimulation. There is also a feedback cycle where the fetus sends signals back to the womb and that entire communication process is currently very little understood. Clearly the more closely related the species the lower the risks, but still it's not simple.
It's hard to know when someone will make the big breakthrough that's needed but quite simply - for the next ten to twenty years this will be used for saving endangered species and studied in animals.
Depending on how many complications that does or does not find human trials would be technically possible but would run into a legal and ethical minefield that could hold them up indefinitely.
So really 20 years from now is the soonest likely to be possible (if everything turns out to be fairly straightforwards) but never (except for people acting outside the law) is just as likely.
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**[Canonical Definition:](https://worldbuilding.stackexchange.com/questions/22417/how-could-a-time-traveller-communicate-with-neanderthals)**
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> A Ssiws Army Man-portable Omnitool (more often referred to as a Ssiws Army Knife) can easily dispatch cave bears and moderately large dinosaurs, carve through granite, print circuitboards onto sand. But most people outside of Draconis Prime use it for opening beer bottles.
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**Context:**
The ***Ssiws*** are a group of hardcore outdoors enthusiasts on Draconis Prime. Aside from one automated spaceport on a deserted island 40 km off the shore of the main continent, no residential stock, industrial plants or transportation infrastructure exists on the planet surface. The vast robotic industrial plants are located the system's asteroid belt, while most of the permanent habitats, hospitals, cloning vats and nurseries are in geostationary orbit above the planet.
The entire planet is covered in eco-engineered✤ forests and jungles (designed by the famous ecopoetess [Deirdre Skye](https://worldbuilding.stackexchange.com/questions/11637/intelligent-cats-with-a-serious-attitude-problem)) that support an astonishing amount and density of plant and animal life, ranging from titanium-stinger insects, razorbeak birds, to giant tungsten-carbide-toothed dinosauriade, virtually all of it either poisonous or highly aggressive towards human-like beings.
The Ssiws ***love it***, and spend most of their lives roughing it out in the jungle.
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**Question:**
**Given the description of the planet and the Ssiws, and the extant definition already in place, I would love feedback on the existing features, mostly with explaining how they can work in such a small device. If you would sooner replace them with other more useful ones, that is acceptable too, as long as you can justify it. The SAK is easily carried in a pocket and is (over)powered by a miniaturized zero-point drive, capable of providing up to a Megawatt of power.**
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✤ A series of orbital mirrors provide 10x normal irradiation on daytime side, a level optimized for the amped-up plant life. Deep sea organisms are designed to speed up and magnify the carbon cycle and sea Leviathans spew processed ore dusts into the air. The ores are taken up by the plants and animals on the surface and used in their body plans. Planet surface has been amply modified for maximizing rainfall such that there are no deserts or plains, just vast jungles and forests
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Outside of what has already been mentioned, there is the idea of ["hacking matter"](https://en.m.wikipedia.org/wiki/Hacking_Matter)(see *free* eBook), where an array of quantum wells is manipulated so the electrons trapped within are stimulated to different orbital states to create "artificial atoms".
Since most of the observed properties of matter are based on the interactions of the electron shells and valence levels of the electrons in the elements, the fact that there is no nucleus to the artificial atoms simply means that properties like mass and inertia default to the mass of the material housing the quantum wells. Theoretically you can have a "tablet" of material which is "charged" so the electrons mimic steel. Now the tablet has most of the properties of a tablet the same size made out of steel. Looking for other patterns in the USB flash drive attached to the tablet, we find gold. When gold is selected through the input, the electrons move to new configurations and suddenly the tab takes on the electrical, thermal and reflective/optical properties of gold.
This is not quite the same as the ability of the Omni-tool to manipulate matter external to itself, but with a lot of tweaking, this idea could be the basis for a similar or related device. Alternatively, if parts of the internal mechanism can be modified to use artificial matter chips, then varying the property of the chips could result in different outputs being possible for the tool itself.
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**Just use a megawatt laser projector.**
A megawatt laser with computer controlled mirror(s) can be used as a weapon and for pattern [sintering](https://en.wikipedia.org/wiki/Sintering). This can also be used for pointing.
The megawatt laser use as a weapon is fairly obvious, cave bears and dinosaurs are vulnerable to megawatt laser burns. Actually not many things can dissipate that much power easily. Especially at that density.
By having mirror(s) able to rapidly change position (like a DLP), the laser can be directed to draw out shapes or patterns. Patterns like the traces on a PCB. When directed at a material like sand (of a conductive material), it can be sintered into a conductive network. You'll need a non-conductive substrate to hold the traces.
It's probably safest to just add a regular bottle opener to the back.
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My first thought would be gallium. Gallium is a metal that is a liquid at [just above room temperature](https://en.wikipedia.org/wiki/Gallium). Gallium is also used in various types of semiconductors, including [microwaves. infrared devices, and high-speed switches](https://en.wikipedia.org/wiki/Gallium), even items that are already versatile like LEDs and transistors (which can be tweaked to be used as a power source/receptable/converter). It also used as a [dopant](https://en.wikipedia.org/wiki/Dopant) to create low-melting metal alloys. Another really cool feature of gallium is that it will [produce lasers when conducting electricity](http://education.jlab.org/itselemental/ele031.html), and can also form neutrinos, tiny uncharged particles commonly found in the sun.
Now, given that this tool will be used in an area with tropical temperatures, you're going to need a better solution, or at least a work-around. A simple option would be a gallium alloy that is (just) above the temperature of the habitat (and you could have different models of this tool, a cool economical factor), or you could use an insulator like silicone, which is also known for its myriad of uses including [lubricants, sealants, adhesives, resin and the vulcanization agent for rubber](https://en.wikipedia.org/wiki/Silicone).
However, gallium is brittle when solid and would either deform or easily break and shatter if used as a blade. Since you want to cut granite with it, you could [seed](https://en.wikipedia.org/wiki/Seed_crystal) it with diamond. This would create a diamond-gallium crystal, taking advantage of the hardness of diamond but making up for diamond's brittleness. But this removes the flexibility of gallium.
If you want to play with quantum physics, you could use a device that controls the quantum state of gallium forcing it to take a certain state for a certain function. Liquid metals can also be controlled to an extent with [direct current pumps](http://demec.ufpr.br/reterm/ed_ant/17/artigos/science01.pdf), but this wouldn't necessarily allow you to control a solid metal.
Yet another option is gold. However, gold is naturally much rarer and much more expensive to produce and use (on our planet, it can be efficient on another planet, especially with superior technnology - Mystra007), and while gallium is brittle but can be strengthened, gold is always soft, even though its melting point is much higher. I suppose you could make it like playdoh, and the users would have to manually mold the gold, but then there's no way it can be a blade.
It seems your only options for the device you described are in the realm of theoretical science, using a [copper-cadmuim alloy](http://www.cadmium.org/pg_n.php?id_menu=10) or something similar, or a gold-gallium alloy with modified characteristics. Using the latter option seems like your best best in my opinion, and using a [quantum device](https://en.wikipedia.org/wiki/Quantum_technology), or using an integrated circuit that can control its shape. I don't know of any real-world examples, but [Van in GunxSword](https://en.wikipedia.org/wiki/List_of_Gun_Sword_characters#Van) uses a shape-changing "memory cloth", so I suppose you could make a shape-changing gold-gallium memory crystal, combining all the bits of science together.
The simplest option yet could be a living weapon. Since your animal species listed all have inorganic metal body parts, you could have a bacteria-based tool, or biological pseudoscience and that gives you all the theoretical flexibility you could possibly need.
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Last month Mobius asked [a question](https://worldbuilding.stackexchange.com/questions/18894/physics-issues-for-a-city-where-time-flows-in-two-directions/19240#19240) about a world where time can flow both forward and backward. I suggested a particular solution to the problem he was looking at, and I would like to open up a follow up question as part of the fortnightly challenge.
**The world of two streams**
In the world I am looking at, time flows in two counterflowing "streams" with eddies connecting them. In the "live" stream, we see physics like usual. Quantum mechanics, general relativity, take your pick from modern science, we see these behaviors in this stream. The other stream is the "dead" stream, and it is where we go when we die. The physics of this stream will be constrained shortly, but the most important trait of this stream is that entities within this stream travel in the opposite direction of time. Any entity can enter this reversed stream simply by dying. Any entity within the dead stream may re-enter the "live" stream at any point [in the past] that they please, simply by wishing it so when they get there.
The physics of the dead stream are open for interpretation, but they are constrained in a way that guarantees consistency. The dead stream is ruled by knowledge and information. As you travel back in time along the dead stream, you are *obliged* by the natural laws to forget enough information such that, if you return to the world of the living, you have forgotten too much information to allow you to force a paradox to occur. For example, if you traveled back in time to kill your grandfather, you may be forced to forget your own last name. Or you might be forced to forget that you wanted to kill them. Or you might simply forget a key detail of your grandfather's personality that allows him to dodge the murder attempt at the last moment.
Feel free to set the rules for this forgetfulness in any way that supports your answer, with one caveat. The forgetting occurs inside the dead realm, not in the transition from dead to alive. The dead must constantly be forgetting enough to ensure that they have no opportunity to create a paradox. If they avoid a "cusp" where a paradox could have occurred, but they elected not to cross back over to the living at that point, they still have forgotten the information that *could* have been used to cause a paradox. The universe is overcautious in that respect.
This also means that the path one takes in the dead stream matters. If one chooses to observe cusp after cusp before arriving at a location, they may have had to forget more than if one chooses to sidestep cusps entirely, arriving at the same location. A dead entity which wishes to avoid forgetting would be wise to avoid sensitive areas of spacetime on its trip backwards through time.
**Religion of two streams**
For this question, I am looking for what traits we would see in religions which are not seen in our simpler unidirectional "arrow of time" approach used in the modern world today. Consider that a dying individual could travel back in time so far as to get "lost," forgetting all that made that entity an individual (but a Buddha, which theoretically knows only eternally true facts, could travel backwards forever without change). **Self interaction is allowed in this world**, so a religious individual could go back in time to teach his or her younger self, as long as that teaching did not invoke a causality paradox (if it would invoke such a paradox, the older version would simply find that they forgot too many details to cause the paradox). Obviously, in this world, life after death is a known thing, but there might be whispers of a "true death" that goes beyond simply entering the dead stream.
## What traits would be found in religions of this world?
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**Judging rules:**
* I am interested in traits of religion which do not tend to appear in our world. I am looking for traits which are specialized to this particular universal structure. At the very least, if the trait exists in our world's religions too, the structure of this universe should dramatically amplify its importance.
+ The best answers are those which demonstrate a religious trait so profound that its mere presence will shape the world we build around a character. I'm looking for something that changes the world, not something which can be kept isolated inside a monastery.
* The physics of the dead stream are open for interpretation. However, the universe should support a dualist viewpoint: in the live stream, body and mind/soul are attached. Moving to the dead stream separates the body and mind/soul, allowing the mind/soul to move backwards. (You are free to define a physical version of the dead stream, if you so prefer, but I should be able to treat the answer as though there was a separation between body and mind/soul, and you'll have to ensure information theory proves that your world prevents paradoxes)
+ The effect of a mind/soul trying to enter the living world in a location where there is no body for it to inhabit are up to you. It could be a "true death," or it could turn you into a ghost to haunt for all time. You might possess someone nearby, or you might simply enqueue to be given the "next available body nearby." Feel free to use imagination if it helps build your story for the religious traits offered as your answer.
* Small and profound is better. It is best if a single trait explains multiple facets of people's world-view within a world. To use the example I already gave, one can define Nirvana within Buddhism within this particular universe. That definition also starts to define "ghosts," in that they are souls that forgot who they are along the way.
+ I expect the religious traits to be very dependent on *how* the universe goes about choosing what information the dead forget. Do not be afraid to specify details about this process. Just make sure that those details do not leave loopholes which would allow paradoxes to occur.
* Answers should leverage the atypical nature of the dead stream. Obviously any solution along the lines of [Novikov's self-consistency principle](https://en.wikipedia.org/wiki/Novikov_self-consistency_principle) can trivially be proven to meet these rules, but they are well explored answers and lead to less interesting outcomes. Novikov started from the assumption that the physics of spacetime which contains spacetime loops is identical to that of physics of normal spacetime (that which has no loops). I am explicitly starting from the assumption that there are regions where the physics differs in some portions of the loops.
**EDIT**: There was a question about what form dead mind/souls return to the world of the living in. The answer is up to you. The intent is to allow one of these souls to "recycle" into a newborn baby body (at the moment of ensourcelement), thus providing the mind/soul with a new body to use. However, to avoid over-specifying the system, I allow the dead to return at any time and place. This may turn them in to ghosts or shadows, or it may simply scatter their mind across all space time. It could also lead to superstitions like saying "bless you" after the sneeze. The origin of that ritual is that it was believed a demon could sneak in up your nose after you sneeze. Perhaps that myth is not as far from the truth as we think today. Perhaps you drop your guard when you sneeze, giving a dead mind/soul an opportunity to partially hijack a fully grown body.
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## Certainty
Ok, yes, some of today's religions claim certainty too -- certainty about what God wants, about what happens to you after you die, and other matters. But none of it can be proven; it's a matter of faith. On the other hand, the dead stream gives us the possibility of **evidence**.
In our world some believe in reincarnation and that they can identify their past lives. You might find a past-life idea that resonates with you and that might bring you some peace. That's nothing compared to meeting *your future self*, who can provide identifying information. (On that: we should expect that there will be certain categories of information that people now guard carefully, things that only you and future-you would know, so that these checks can be performed.)
Meeting your future self provides some reassurance about your future. Your future self can't tell you tomorrow's lottery number or anything like that, and probably can't even tell you when you're going to die, but you know that you *have* a future, at least a little. Bed-time prayers ("now I lay me down to sleep" etc) will probably change.
Back to certainty. Enough people meeting their future forms and learning about the dead stream will validate some religious ideas and challenge others. There will still be differences of interpretation, but I would expect this common, shared body of knowledge to push people toward a common body of baseline beliefs. For one thing, we're pretty sure now that there *is* an afterlife; you don't just die and get stuck in the ground and that's it. Instead of trying to make the best life for yourself here and that's it, you now have a whole afterlife to contemplate too.
## And uncertainty
So, what does it mean that you've never been visited by your future self? Did something bad happen? Did your future self die horribly and wants to avoid you lest you find out? Did your future self mess up and "overshoot", and he's now back in your grandparents' time? (Presumably not proceeding to be his own grandpa, because we're avoiding paradoxes here.) Or did he become one of those phantoms that people sometimes talk about?
There will be people who never knowingly have an encounter with someone coming back through the dead stream, and this will lead some of them to conclude that people *don't* always come back. So if they don't come back, something else must happen to them, right? So the idea mentioned in the question of ghosts and phantoms will be a real belief, even if it's not actually true. It's part of human nature, I think, to let our imaginations fill in what we can't verify -- both good and bad.
Since people, it appears, enter the dead stream with the memories they had in life, the deaths of the very young will be seen as especially tragic. Before one is old enough to think and reason and have a basic body of knowledge, one won't know enough to be able to come out again. When babies die they're *gone*, or so many will believe, because how would they know enough to "steer" in the dead stream? At the other end, people who die with dementia are probably *gone* too. It is possible that the latter will lead to a higher suicide rate among the elderly -- better to go now while the brain still works than take your chances, some might say. We should expect some religious views that say this is not only ok but divine will, and others that say that it's terrible and that you're not supposed to "live" forever through the dead stream.
Some will wonder what happens if you decide not to come out of the dead stream. Can you go back to the neolithic age? To the formation of the earth? To the big bang? There will be much philosophy about this but no one will be able to find out. Possibly a focus on the "before-life" (so to speak) will replace the focus some have today on the afterlife.
So there'll still be plenty of uncertainty, but the key difference is that people will know that you have some control over your future path, and therefore people will see meaning in all contacts -- and non-contacts -- from the future.
[Answer]
I've just discovered this, so apologies for such a long delay!
So, some thoughts:
1) information has to be encoded in something (e.g. spirit matter, energy patterns etc.) and its degradation would be, almost by definition, *entropy*.
2) Hence, would people try to limit the entropy as much as possible, once they worked out that the universe worked in this way? perhaps by encoding a specific memory in multiple ways (so at least one way would survive the trip back). Think, for example, of Thomas Edison's experiments to contact the dead, and Spiritualism as a whole, and some of the Buddhist meditation practices which are about surviving aspects of the afterlife , and so forth. In essence, people will attempt to 'hack' the system and seek a way around the problem. If at any point in time, the physics of 'energy patterns/spirit matter/whatever mechanism' are deduced, then a technology may be derived to minimise entropy, or force some edge-case in the physics which would allow a breaking of the rule... Perhaps.
3) Maybe I missed it in what you said, but if people can come back at any time, can they not come back at a time prior to their forgetting too much? Can they come back as their own re-incarnation, thereby immortalising themselves within a time loop? Could the go back to their living self, and retrieve what they have lost from their living former self? And then keep replenishing their memories?
As for effects on religion:
1) prophecy would be big - and done right, more reliable; here's how my religion would do it: A) Supply a message you want to send to the past to a lot of people. B) Kill them all. C) They report to your former selves, but although entropy means they've lost information, they've probably not all lost the same information in the same manner, so each will have a small piece of the message. D) Apply statistical methods to put the fragments together and get some idea of the future.
2) Deceit via prophecy can be done in the same way - just get you're murdered population of death-travellers to tell lies (or lie to them all)...
3) What about temporal edge cases? Can you die/come back at the very edges of Time itself? The start or end of the universe? If you could retrieve *any* information from such times, you'd have clear stories about how the universe starts and ends.
4) There'll be stories in the myths of people from the 'future' meeting the heroes of the stories. Perhaps advising them etc.
5) Mostly, however, I'm not sure religion will be that different, because it already claims all these things. The only difference may be if there was a scientific means of demonstrating, verifiably, that the universe works this way... And given that we already live in a world where there are consistencies in the stories of people who have Near Death Experiences, where stories (cases) of supposed re-incarnation exists, prophecies etc.. I suspect it'll have the same scepticism we have now, which is kinda interesting, I think...
6) I think it all hinges on getting accurate, concrete factual information out of the dead/re-incarnated by some means. If that can be done, and repeatedly, then there's the scientifically verifiable proof one needs to turn religion into science and fact. Deceit aside, no more doubts about the afterlife, or the origins and end of the universe. Scientists will look for ways to exploit this for time travel, space travel etc. Governments and anyone with resources will try to gain prophecy as a means of power. Religion will die, and be replaced by the Science of the Hereafter.
So my answer would be this: If no reliable information can be garnered, it'll be identical to what we have now. Otherwise... *huge* differences, but religion will be dead,replaced by a fascinating new science. Science if what you get when you put religion and magic under the microscope - Consider Newton - he spent more time searching for secret messages in the bible than formulating physics as we now know it. He studied alchemy. All this was because in his time, there wasn't a distinction between magic and science - science was born of magic once you worked out what the rules of the universe really were, and Newton etc. were merely trying to understand how the universe worked (by seeking underlying rules to phenomenon, such as reactions in alchemy, or 'magical' processes, and finding them wanting or verifying an effect which could be studied).
Hope that helps!
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[Question]
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Setting: A version Medieval Europe where magic has always existed, but has evolved in a similar way to how technology changes, getting better with time. Eventually, someone figures out how to give a "sentience" to objects, given that the object meets some requirements.
* Somewhere inside of the object there must be a magic core, which can be created by concentrating a moderate amount of magic into a rock (6 hours of channeling by a basic mage, less by more powerful ones for a rock equal to or less than a 1 foot by 1 foot by 1 foot cube. The spell does not work on bigger rocks).
* The object must be able to move like a human, so it must have a body, 2 arms, 2 legs, and a head. These do not have to be detailed, but must still be connected. An easy way to do this is via short chains. If the chains are too long, or a part is too disproportional to the caster's body (magic uses this for reference), the spell will not work.
* The golem's body can not exceed an 8 foot tall by 5 foot wide by 5 foot long box (if set up like a mannequin). It can exceed it via movement. It the body exceeds the box, the golem shuts off until it has been changed to fit the box. NOTE: More powerful mages can exceed the size I said, but I am trying to set this up around common people and not master grade mages.
* Up-keeping a golem is not a task that has to be always done. But, while a golem is active under a person, that persons magic reserve maximum is dropped until the golem is either deactivated, or the core is destroyed. If the user does not have enough magic to upkeep the golem, but still tries, the person will go unconscious, and the core will be destroyed.
The golems (base ones) can carry as much as the material they are made of can handle. Any more, and they begin to crumble. Their speed is also dependent of
the material, with heavier ones moving slower.
With the exception of combat, their AI has little to no intelligence (a more powerful mage can give one with more intelligence)(in combat, ordering it to attack will cause it to try and punch/bash whatever you order it to attack). The core though, links the minds of the creator and the golem. This allows for some level of control over the golem, besides voice commands. When not taking orders, they stand still like a statue. They are easy to notice while active though, seeing that the core, along with any links linking body parts together, and a dot on the face will all be glowing a random hue (stronger mages can set this hue).
Extra Info:
* The basic person has the energy to have 0-2 golems active at a time.
* A golem can not be created of organic matter (the body parts), but can be garnished with it, like wood details or a flower laurel.
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So, how would Medieval Europe change with the discovery of the ability to make golems?
[Answer]
So these golem, having very little intelligence/autonomy are basically machines.
They would have an effect similar to the invention of the engine, without the need for fuel, but still need near constant supervision.
You hook one to your plow instead of oxen and work the field. Teams of golem pulling long trains of wagons along the roads, or on specially built tracks. Golem carrying deliveries through crowded streets to shops. Strong mages with extra large golem running construction projects. Golem in factories turning gears to run assembly lines. Armored golem with huge swords or mounted siege weapons. Knights mounted on special fast golem ridding into battle, crashing into enemy golem holding up a giant shield wall. The king oversees the battle upon his war palanquin, supported on the shoulders of 20 golem, mounted ballistas and trebuchets raining hell upon the enemy...
You could probably set them and forget them for some tasks, like say pumping water to irrigate a field, as long as you made sure it didn't flood the field by pumping to long.
The poor that worked the land would have 1 or 2 simple golem made of clay, able to pull a plow and carry some loads, decorated by the children with designs painted with berry juices and other simple dyes. The rich would have golem made of stronger stuff, stone and iron, inlaid with other metals, and imbued with enough intelligence that they wouldn't have to be supervises as much, as well as having golem wranglers on staff to supervise the ones that do the low level tasks.
Edit:
Why I think the poor would have one: oxen for plowing. A golem would be cheaper than an ox simply because it wouldn't need food or rest. And a golem might be cheaper than an ox if you were willing to do a little DIY.
So you go out to the clay pits and get a big load. Bring it back to the farm and form it into shape. Then buy the core and put it into the body. As the golem wore out you'd patch it with more clay, or make a new body to put the core into.
[Answer]
Remembering from [Seventy-Two Letters](http://web.archive.org/web/20010802144026/http://www.tor.com/72ltrs.html), it brought industry before/instead of steam. A large iron golem worked the forge, for example.
Ted's story was not out-of-nowhere, but the possibility of golems in real life affected the physics and science of his universe.
Look at the issues of taking away jobs from guild members (organized unions), and doing jobs taken by unskilled children like dragging coal out of mines.
If magic can power motion, would they *need* coal for industry? The animating mana (like Nivin's consumable resource) might be needed instead.
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[Question]
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With news about the Faroe island solar eclipse, I wondered if a constant solar eclipse would be possible.
Is it theoretically possible to move the moon or some large object into the L1 earth-sun Lagrange point or would it be too large?
How else could a constant solar eclipse be achieved?
What would be the maximum size of such an object or could some other shape like a disk more effectively achieve this?
[Answer]
Math Time!
What do you need in order to block out the sun at the L1 point?
Well, the Earth/Sun L1 point is located roughly 1,500,000 km away from Earth. in order for a 'solar eclipse' to occur, we need an Umbra (total shadow) to reach Earth from the object. This means that the angular diameter of the object (apparent size) must be greater than the sun. Wikipedia says that at perihelion, the sun has an angular diameter of 0.5450 degrees So, we need something that is apparently that big or bigger.
The equation to find Angular Diameter is:
$$\delta = 2\arctan(\frac{d}{2D}) $$
where d is the actual diameter of the object and D is the distance to the object. Rearranging, we get this.
$$ d = 2D \cdot \tan(\frac{\delta}{2}) $$
plug in values
$$ d = 2\cdot 1{,}500{,}000\cdot\tan(\frac{.5450}{2} ) $$
and solve...
$$ d = 14{,}268.174\,\rm km $$
For reference, the Earth's diameter is 12,742 kilometers, so we are going to need something bigger than our planet.
As others have mentioned, the L1 Lagrange point is unstable...if you drift off of it, you fall towards one body or the other. So, you are going to need a monstrously powerful system to stabilize it. If you are willing to put in serious effort in keeping it from sliding around, you could potentially make it out of something light (like several layers of graphene) but you have to contend with the Solar Wind at that point.
On the other hand, if you make it too massive, something that big is going to have a gravity well, in which case we have just jumped down the rabbit hole of chaos theory.
And, to be clear, this is not to eclipse the entire planet...this is just to have a moon-sized solar eclipse at all times.
Something this big also has to contend with getting hit by space debris (and it doesn't have an atmosphere to protect it from meteorites). Graphene is really tough, and might be able to survive the impact, but that is yet another thing trying to knock you off station.
Assuming you use graphene, with is about the strongest thing we currently have...a single sheet of graphene would block out roughly 2.3% of available light. To block out all light, you need 44 layers. Graphene has an approximate mass of 0.8mg per square meter. So a square meter of light blocking graphene would weigh 35.2mg.
Our eclipse creating disc has an area of
$$1.6\cdot 10^{14}\,\rm m $$
Multiply that all out....
$$ 56{,}320{,}000{,}000\,\rm kg $$
That is a lot of weight, but not as much as any of the larger asteroids in our system. But bear in mind that this is only for the sheet of graphene...which at that size would be tremendously flexible and need to be braced, reinforced, and then still add the stabilization system. All of which would increase the mass dramatically. And the bracing would need to be extremely robust...stabilizing something that massive would be...insane.
In short, I don't think this is feasible without some *serious* future tech, and maybe a bit of applied phlebotinum.
For other alternatives, try using a ring around the planet, or something else that doesn't have to be nearly so enormous.
[Answer]
For stability, the best way to permanently eclipse the sun would be with a ring.
If the Earth had a ring like Saturn, it could filter the sun from one hemisphere for the whole winter.
Maximum size, a dyson ring inside earth's orbit could be set up so that some of it would always be blocking some(or all) of the sun.
[Answer]
Since creating an object 8 times the size of the moon is impressively hard, there might be another way that is still impressively hard, but more practical.
Why isn't there a solar eclipse every new moon? It is because the moon's orbit is inclined relative to the Earth's orbital plane. On average, the moon is a bit smaller than the sun, so the moon needs to be nearer perigee to have a total eclipse.
So the obvious solution is to adjust the inclination and distance of the moon so that you have a total eclipse every month!
Since this only happens over a small region (and if you make the orbit inclinaton exactly 0 only at the equator) I can't see there being any real effect on a monthly eclipse except make it boring and mundane.
[Answer]
It is possible.
1. Put boosters with power enough to make the Earth and moon stay in same place in Solar System (1 pointing the direction opposite to where our Earth is going now and 1 pointing to the sun so that our Earth won't go straight to the sun) and put them on the moon too, later (when the speed of Earth and moon is zero), stop the booster that is not pointing to the sun
Edit:yeah, it will be unstable and by the fact that Earth is always spinning around, we need to make it a booster train that can go across the Earth.
and let's just put in on the moon so it will be a lot easier.
2.Make a Satellite that is big enough (with size that have the same size of sun on the distance it is from Earth looking from the ground) to cover the sky that is always in the Lagrange point to use it as artificial moon.
(these require much resource, fuel and energy more than we know now)
[Answer]
The only way would be to have it artificially induced. Moons orbit a planet, so putting a moon in one spot between the planet and the sun (or any other large enough object) it would need stabilizers to keep it in that position. If you are thinking about some other object orbiting the sun that stays in between, well, the speed of the orbiting body is dependent on the distance from the sun, so a body closer to the sun would travel faster. Granted if is was large enough and close enough to our orbit, every couple thousand years we could have a month or 2 long eclipse as the planet passes us by.
One thing to think of in that case is Janus and Epimetheus, they are two body's that are so close in orbit that they switch orbits when they get close, they never pass each other, they are more like relay racers, one 'hands' off to the other then slows down to the outside lane and the first speeds up into the inside lane. Planets would likely cause tectonic activity when they approach each other that close too.
[Answer]
A soletta/solar mirror could work.
In [Green Mars](http://en.wikipedia.org/wiki/Mars_trilogy#Green_Mars_.E2.80.94_Terraforming) a giant solar mirror is put in Mars L1 point, and magnifies the sunlight to make Mars brighter and warmer. It's held in place by stabilizers and also through a solar sail type effect. Another is put in Venus L1 point to block all sunlight and freeze the atmosphere, so it could be replaced with something less lethal.
>
> “Well, and now with this soletta pouring sunlight onto the surface!” Jessica exclaimed. She shook her head, as if disapproving. “Natural insolation averaged forty-five percent of Earth’s, and with the soletta it’s supposed to be up to fifty-four.”
>
>
> “Tell me more about this soletta,” Sax said carefully. They told him in a kind of round. A group of transnationals, led by Subarashii, had built a circular slatted array of solar sail mirrors, placed between the sun and Mars and aligned to focus inward sunlight that would have just missed the planet. An annular support mirror, rotating in a polar orbit, reflected light back to the soletta to counterbalance the pressure of the sunlight, and that light was bounced back onto Mars as well. Both these mirror systems were truly huge compared to the early freighter sails Sax had enlisted to reflect light onto the surface, and the reflected light they were adding to the system was really significant.
>
>
> “It must have cost a fortune to build them,” Sax murmured.
>
>
>
If a soletta was put into the L1 point, but then sabotaged or just glitched, it could direct the light away from earth and cause a permanate eclipse of the sun.
Now for a reason why they might put a soletta in Earth's L1: Global warming. Earth getting a little to hot, so direct 5% of the light away, and cool things down a bit, like a giant thermostat... but something goes wrong.
**Addressing comments**
You wouldn't need it all the way out in the L1 point. It could even be inside the moons orbit, using the pressure of the solar wind to keep it in place, along with thrusters and stabilizers. This would reduce the size needed.
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Another theory could be that some mass just large enough could smash into the solar system. If conditions were just right, and it got caught by the sun's gravity, it could match the Earth's orbit and block the sun. It's just my own idea lol, not saying its totally possible.
[Answer]
A personal drone hovers above each person, blocking the sun for glare reduction purposes. They either recharge at night, or take turns seamlessly from a fleet.
Might be cheaper than any astronomical solutions. It's surely more sustainable for the environment.
If costs are still too high, it may be scaled down, e.g. for the rich only.
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[Question]
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In my fantasy world, Mainspring, the top of the oceans' food chain is the maculatum, a species of giant eel which originated on another plane/dimension. Maculatum reproduce asexually and wthout any intention: they constantly excrete an oily fluid slightly heavier than water which, upon pooling on the seafloor in sufficient quantity, congeals into something like an egg. When the egg hatches, several three-inch-long maculatum emerge and immediately begins hunting smaller creatures (and each other). The primary drive of a maculatum is its constant hunger, as it gets 10% longer and thicker every week, compounding indefinitely until the square-cube-law or its own caloric needs crush it into ineffectiveness and, eventually, death.
My question is what the general upper limit for size would be on one of these oily eels given that constant growth, and whether it would typically be starvation or collapse that killed them first.
Other information that may be relevant:
* Despite their biology being alien to Mainspring, maculatum get energy from their prey at the same rate a mundane eel would.
* Aside from some exceptions notable enough to have personal names instead of species names, the largest creatures in the oceans are whales and giant squid (and possibly maculatum).
* The materials of the maculatum's body have the same relative strength as that of a moray eel, and they employ the same hunting methods.
* When a maculatum dies its body denatures into the same oily fluid it is always excreting (edit: @datacube mentioned that having it nutrientless would lead to total ecosystem collapse).
* The oily fluid tastes bad but is highly nutritious, and is therefore favored by scavengers, who will occasionally hunt young or adolescent maculatum.
* The only humanoids who tend to mess with maculatum are merfolk who harvest the oily fluid for its use as a memory-enhancing drug.
[Answer]
# 8 Metres. But Eel is a Bad Body Plan.
Like your Big Flat Eel, both crocodiles and sharks are suspected to continue growing throughout their lifetime. Though the growth slows down as they age. Wikipedia says the largest specimens are about 20 feet long. Of the two, the shark is heavier, with one great white shark named Deep Blue being estimated at 20 feet long and 2 tonnes.
The presumption here is that modern seas don't contain enough food to support and animal much larger than Deep Blue.
[](https://i.stack.imgur.com/RfGA5.png)
Let's take a Conger eel and scale it up to 2 tonnes. [This paper](https://www.researchgate.net/publication/263453158_The_age_growth_and_feeding_habits_of_the_European_conger_eel_Conger_conger_L_in_the_Adriatic_Sea/figures?lo=1) suggests a 1 metre (3 feet) conger weighs about 4 kilos
[](https://i.stack.imgur.com/ZZDUB.png)
Scale that up to two tonnes by multiplying by 500. To multiply the mass by 500 you multiply each dimension by $\sqrt[3]{500} \simeq 8$. So 8 metres of eel weighs about 2 tonnes.
(That's not much more than the shark and the eel is also thinner than the shark. Hmm. . . I wonder how reliable the shark estimate is.)
8 metres is only a touch longer than [this oarfish](https://en.wikipedia.org/wiki/Oarfish#/media/File:Giant_Oarfish.jpg) found washed up on the shore near San Diego, California, in September 1996.
[](https://i.stack.imgur.com/bvNNv.jpg)
The issue is now that oarfish is a relatively slow filter feeder. It is not an apex predator. The apex predator Deep Blue eats whales and sealions. Sealions are fast and nimble.
[](https://i.stack.imgur.com/m24Jl.gif)
The 8m eel can maybe hit a high top speed. But it is not nimble. It cannot keep up.
I suggest your eel has either sonar or electroreceptors. It is an ambush predator, like real eels, and hunts in murky seas by lunging at them before they have time to react.
The numbers aren't all that impressive, are they? For me the issue is not the size but can a long lanky creature move rapidly enough to be an apex predator?
Oarfish cannot lunge, by the way. [They swim by undulating the crest of fins on the back.](https://www.youtube.com/watch?v=b1I-4-oL4WU)
[](https://i.stack.imgur.com/hzn3y.gif)
[](https://i.stack.imgur.com/KdQkM.png)
<https://www.youtube.com/watch?v=b1I-4-oL4WU>
If this was my world, I'd say my ocean contains something big an relativel slow for the eel to eat. Like some Dunkleosteus:
[](https://i.stack.imgur.com/wscda.jpg)
and the eel is the length of the mighty Megalodon:
[](https://i.stack.imgur.com/UuF88.jpg)
These bad boys are about 60 feet long.
Since the eel eats armored fish, it is also well-adapted to eat ships, which are a little bit like armored fish, and their crews.
[Answer]
**Apex Predators aren't 'Apex' until they're fully grown.**
Using an example I gave for another question consider the Salt Water Crocodile (salties). It's the apex predator of it's ecosystem and no other creature in that ecosystem comes even close to be able to challenge it's dominance. Yet 99% of salties never make it to adulthood.
Just like your creature young salties are preyed on by multiple species since they're only a few inches long at birth. Birds, fish, mammals, lots of other animals prey on young salties.
And it would be even worse in your world for a young 'Maculatum'. As you note they are only 3 inches long at birth and the ocean is a 'fish eat fish' world. An oceanic environment is hyper competitive, Basically (in broad terms) anything smaller than you is potential prey, anything bigger than you is a potential threat.
Add in other adult Maculatum who regard juveniles as potential competitors for territory and/or a free meal and you start to see why so many fail to make it to maturity. Beyond that if, as you say the 'oily fluid' from which all Maculatum arise is highly nutritious even if it tastes 'bad' there will be some smaller ocean floor species (bacteria, molluscs worms) etc that will soon adapt to eat it.
EDIT: An upper size on the organism is also imposed by the amount of protein available for it to consume per cubic volume of water given a specific feeding style. *Unless stated otherwise* if Maculatum were for instance apex hunters like killer whales there's a bottom limit on how small their pray species can be once they are fully grown (minnows are not on the menu). If they are filter feeders there's an upper limit on the prey size (salmon etc are off the menu).
Over time an equilibrium has to be reached between the number and average size of apex predators and the amount of food available to sustain them. Initially when a new predator is introduced into an ecosystem there would be severe oscillations in predator/prey populations (cycles of boom/bust) that would slowly decline over thousands of years until an equilibrium was reached between predator and prey. That or the system collapses and the predator goes extinct due to a lack of food.
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[Question]
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An early warning scout ship sits in deep space, making various kinds of observations and doing deep space science experiments, when suddenly a 2-kilometre-wide asteroid zooms past at about 0.9c on its way to ruin someone’s day. It takes all the observations it can as it passes and forwards them to home base to take action.
The scout has a comprehensive suite of instruments that allow it to observe the asteroid via all currently-known (as of ~2022) active and passive methods\*. It lacks any science-fictional/magical sensors applicable to the task.
The asteroid can be assumed to pass the scout at a distance of approximately 1,000km, or the minimum distance that the scout would not affect the asteroid in the course of its observations. Assume that the scout can survive the experience. (If simpler, it can be treated as an abstract point directly intersected by the asteroid.)
What would the scout be able to observe and report back about the asteroid?
Actually stopping or deflecting the asteroid is not in scope here - assume appropriate countermeasures are implemented with scifi tech.
\*Literature review suggests that at minimum the asteroid should be pingable with a radar (or other -dar), and at the requisite velocities might be able to be picked up on infrared and possibly visual from the impact of space dust creating heat.
[Answer]
**At 0.9c, the asteroid would be glowing brightly from impacts with hydrogen atoms in the interstellar medium, and be visible for minutes as it approaches.**
The interstellar medium has a varying density, somewhere around 1 hydrogen atom per cubic centimeter. We'll take the density to be 1.674 \* 10^-22 kg/m^3. We want to calculate how much kinetic energy is being deposited onto the asteroid from impacts with these hydrogen atoms. This is (density of interstellar medium) \* (speed of asteroid relative to the medium) \* (relativistic kinetic energy per unit mass of the medium). Relativistic kinetic energy is (Lorentz factor - 1) \* m \* c^2. The Lorentz factor is 1/sqrt(1 - 0.9^2) = 2.3. [Some dimensional analysis](https://www.wolframalpha.com/input?i=%28+%281.674+*+10%5E-22+kg%2Fm%5E3%29+*+1m%5E2+*+0.9+*+%28speed+of+light%29+%29+*+%282.3+-+1%29+*+%280.9+*+%28speed+of+light%29%29%5E2) says the asteroid at 0.9c would be receiving about 4.3 kW of power per square meter in kinetic energy from impacts with the interstellar medium. If the asteroid is in thermal equilibrium because it has been traveling for a long time, it will be radiating away the same amount of power that is hitting it.
At 0.9c, the [Stefan-Boltzmann law](https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law) says that 4274 W of radiation per square meter means the front of the asteroid is at about [250C, or 524K](https://www.wolframalpha.com/input?i=%28%284274+W%2Fm%5E2%29+%2F+%28stefan-boltzmann+constant%29%29%5E0.25). This is hot but not red hot, so the asteroid would be completely dark to the naked eye if you were standing on it. [Wien's displacement law](https://en.wikipedia.org/wiki/Black-body_radiation#Wien%27s_displacement_law) says it would have a peak wavelength of about 5.5 micrometers, which is deep infrared.
However, any light from the glowing asteroid would be [Doppler-shifted](https://en.wikipedia.org/wiki/Relativistic_Doppler_effect). It would look blue on approach and red as it receded. The relativistic longitudinal Doppler factor, sqrt((1 + 0.9)/(1 - 0.9)), is 4.36. According to [this](https://en.wikipedia.org/wiki/Relativistic_Doppler_effect#Doppler_effect_on_intensity), this means can just multiply the temperature in Kelvin by 4.36 to get the apparent blackbody temperature on approach. This would be about 2013C. Based on [this chart](https://en.wikipedia.org/wiki/Red_heat), that means from the perspective of the scout ship it would be white hot, and visible to the human eye.
The Doppler effect also means we multiply the radiant intensity by the fourth power of the Doppler factor (which, again, is 4.36). So on approach, the asteroid would appear as if it was radiating 4.36^4 = 361 times as much energy. (And as it recedes it would appear as if it was radiating 361 times less energy).
If the asteroid has 2 km^2 of surface area facing the probe and is radiating 4274 W/m^2, this is 8.5 GW of thermal radiation. Multiply this by 361 and we get 3.07 TW.
How far away could a blackbody source radiating 3.07 TW be seen? For comparison, Alpha Centauri A is one of the brightest stars visible from Earth, and telescopes on Earth receive around [2.7 x 10^-8](https://homework.study.com/explanation/alpha-centauri-a-lies-at-a-distance-of-4-4-light-years-and-has-an-apparent-brightness-in-our-night-sky-of-2-7-x-10-8-watts-m-2-recall-that-1-light-year-9-46-x-10-15-m-a-use-the-inverse-square-law-for-light-to-calculate-the-luminosity-of-alpha-cent.html) W/m^2 from Alpha Centauri A.
We can model the radiation as spreading out in a half-sphere from the front of the asteroid, with area 2 pi r^2. To find the r for which the asteroid would have the same visibility as Alpha Centauri A, we set 2.7 x 10^-8 W/m^2 = 3.07 TW / (2 pi r^2). Solving for r gives r = 4.2 \* 10^9 m, or 14.2 light-seconds. That means, for about 15 seconds on approach, the asteroid would be brighter than Alpha Centauri A. It would be very noticeable to the naked eye.
Of course, the probe certainly has telescopes capable of seeing objects 100 times dimmer than Alpha Centauri A. The human eye can see stars that dim. That means the probe would be able to watch the asteroid approach for at least a couple of minutes. It really depends on how good the telescope is. If it's 100 times more sensitive than the human eye it might have 30 minutes of warning.
Pinpointing the trajectory of the asteroid would be fairly simple, given that much time to watch it approach.
Almost as soon as the asteroid passes the probe it would go dark for two reasons. First, you'd be looking at the back of it instead of the front, and the back would be a lot cooler and glowing less, as it's the front that is impacting the interstellar medium. (Assuming it is not rotating, that is! If the asteroid is tumbling then all sides would be getting hit by the interstellar medium in turn, which means they'd all be glowing evenly. That means it would be a couple times dimmer on approach, and wouldn't dim as fast as it retreats. This would be a way to tell whether it's tumbling!). Second, the Doppler effect would be working against you on retreat, dimming the intensity by 361 instead of increasing it by 361, so it would immediately be 130321 times dimmer from that alone.
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I believe it'd be foolish to assume that magic wouldn't affect astronomical phenomena like stellar evolution, But since I'm not smart enough to create the equations for a new fundamental force, I have instead decided on one major effect (for now) existing on stars, and I wish to know how this would effect stellar evolution
* Stars are much more convective in this universe than in our reality, while remaining just as hot and bright. Stars up to 0.6 solar masses are still fully convective like the smaller red dwarfs present in real life; but still burn just as hot and luminous.
The type of star I'm mostly curious of are fully convective stars capable of helium fusion; which don't exist in real life. I have an idea based on intuition, and I'd like to ask if there's any science backing it up.
Here's the intuition based answer:
They evolve like a red dwarf into a blue dwarf stage (Albeit a lot faster) until helium fusion begins at which point it would turn into a red giant; which would evolve like any other red giant (though slower) until it loses so much mass that helium fusion can't be sustained anymore, at which point it contracts down into a white dwarf.
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Of course, the answer depends on the laws of physics you consider to solve the problem. I’m giving an answer based on really basic laws, but it’s obviously possible to give other answers by taking other theories into account (relativity, nuclear physics, and so on).
My answer uses these simple physics models:
* basic thermodynamic: energy conservation and entropy.
* classical mecanichs: energy can be "stored" as movements (linear or rotations), and you have centrifugal forces.
* basic chemistry: nuclear reactions in stars are chemical reactions that produces or consume heat (no radiations are taken into account, this no real nuclear reactions as in modern nuclear models, although I confess this is a shame…).
* since in your model you have a weight loss due to radiation, we will use this complementary hypothesis: energy can turn into mass, mass into radiations, radiations into energy, or any combination of these (basically more or less "e=mc^2")
These models are valid, even if they are not the most up-to-date ones ^^ Or it’s up-to-date in a late 1920’s world.
In this context, the answer is probably yes, with slight differences, due to these mechanisms:
* since you have convection, the atoms are getting hotter while getting closer to the heart of the star. The convection movement can also locally increase the pressure, so the temperature (energy exchange between movement and heat).
* more heat and pressure means more possibilities of nuclear reactions, which brings more light (convection -> energy(heat) -> radiations).
* more radiations, and more heat, so a higher frenquency of radiation -> red light turns to blue (nuclear physics would be useful here, but I said I would do without it) **AND** more pressure so more density, so more gravity, so smaller star -> **this is your first step (blue dwarf)**.
* more accumulated heat but less materials to react, so the energy can just transfer to movement -> the spinning movement increases while nuclear reactions are slower **BUT** also in convection movement (due to your first hypothesis) -> centrifugal force make the star bigger and at a lower temperature (density decreases), but the nuclear reactions last longer -> this is your second step (red giant), with a little difference: the convection lets more nuclear reactions happen… **So it would rather be an "orange giant", not red**.
* at the end of any nuclear reaction (but it will happen sooner than in reality, since the convection lets more reactions happen, so matter reacts faster, so sooner), you have a classic white dwarf. A slight difference will be that convection will not be possible anymore, so the movement will turn into two possible things: rotation speed (you have a **spinning white dwarf**) or heat (you have a "more-than-white" dwarf, which will looks like a white dwarf in visible range, so no difference).
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# Convection Prevents Helium Fusion
[Red Dwarf Information](https://astronomy.swin.edu.au/cosmos/r/red+dwarf)
Red dwarf stars are fascinating, being both common and low energy. Part of their low energy is the inability to fuse helium produced in the core into other elements. This is because convective forces move the helium outside of the stars center before it is able to fuse. These stars thus collapse into white dwarf stars eventually rather than following the stellar evolution of larger stars.
## Magic Would *Alter* This Process
Certainly magical forces could overcome this limitation, allowing the fusion of helium in the core by providing some forces that keep the helium bound into the core until fusion results. Magic is *odd* in that it appears to be more "intelligent" than other forces. That is, in most works of fiction containing magic, the magic force tends to *anticipate* what the magic user intends. Perhaps the stars themselves are intelligent in a similar manner, and simply are building a certain amount of energy while not changing the larger part of their nature, thus remaining convective overall while altering the properties of the convection.
## The Stellar Evolution, A Breakdown of What Happens Next
Looking at what this magical change implies we see a few things:
1. There is more energy generated in the core
2. Stellar evolution would be altered along with the star's energy level
3. Size is typically a function of overall energy and the course of stellar evolution
Thus these stars might not be dwarf stars unless affected by other magical processes
The energy level affects the color, as you have stated. The normal range would be, going from low to high:
* Red
* Orange
* Yellow
* Green
* White
* Blue
A star with helium fusion would be similar to our own sun, and would likely be yellow in the earliest phases of it's stellar evolution. It would also follow a main-line stellar evolution, but would be slightly smaller than our sun. This implies that a similar level of energy could come from much smaller stars and that life could be in some of the most distant planetary orbits of these small solar systems.
I'm fascinated to learn more about how your interstellar magical fiction evolves. There are certainly people here who can help you in your journey to write interesting and compelling worlds.
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I'm trying to design an artificial microbe that could survive in the crust of icy moons and dwarf planets in the outer solar system, such as Pluto and Triton. I'm thinking of making them hydrogen-consuming methanogens, and basing them off azotosomes, artifical cells created out of nitrogen, hydrogen and carbon, with a liquid methane solvent. Technically speaking, all the necessary ingredients are there, locked within nitrogen ice, water ice and carbon dioxide ice, but of course the difficulty is in accessing them. They're frozen solid for one thing, but even then, separating hydrogen from H20 is notoriously energy intensive, and you'd probably end up with a net energy loss. How can I get around this?
The only thing that's come to mind is the possibility of radiolysis, but other than eking trace radioactive elements out of the ice from ancient meteor impacts, I can't figure out how to generate that kind of radioactivity, and that's probably far too inefficient. This is intended to be an artificial species seeded by advanced precursors, btw, so it doesn't matter if any solutions are unlikely to have evolved naturally.
Can anyone help me with this?
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An example species may be [Endolithic](https://en.wikipedia.org/wiki/Endolith) Lichen. Endolithic Lichen actually live inside solid rock, existing in the pores or mineral grains (not cracks mind you but microscopic grains in the rock). They can also get all their energy from rock and not require sunlight (look at the Survival section of the wikipedia link). In [this article](https://www.mdpi.com/2079-7737/2/2/693/htm) Endolithic Lichen is investigated at the McMurdo station in Antarctica. The article also includes a scanning electron microscope image of the cells living in sandstone pores. The authors mention:
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They would be robust enough to survive extreme temperatures, and capable of living in solid rock (and solid ice I imagine as well).
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This is a submission towards the [Anatomically Correct Series](https://worldbuilding.meta.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798%5D)
[](https://i.stack.imgur.com/7mkxm.png)
The leviathan, (in biblical terms), is describes as being a colossal serpentine like creature, it’s back is covered in scales that are compared to the strength of shields. It is also capable of breathing fire and is capable of creating wave that are massive, but isn't capable of destroying a whole city.
The question I want to know is, what environmental pressures would cause for such a creature to exist?
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The late Cretaceous was a prehistorical period (right before that whole asteroid thing) that experienced a high level of oxygen saturation (35% to our 23%), high sea level, and warm temperatures. The warm temperatures are good for cold-blooded creatures (like serpents), the high sea level is good for aquatic creatures, and the high oxygen saturation resulted in some creatures which had poor respiration methods (like insects) being able to grow much larger than they can today. The world would have to be very lush, to facilitate lots of well-fed prey for this Leviathan to feast on. A barren world won't do.
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Some animals, like sharks and reptiles, keep growing until they die. The hypothetical leviathan, if were thousands of years old, would become massive.
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Leviathan could have evolved from a small group of feral goats that had 6 legs due to polymelia. These cows might become arboreal, and shrink down. Due to their small size, they may evolve to glide using wings derived from their middle limbs. They male become more sexually dimorphic, with the males becoming far larger. These larger males would be unsafe in the trees, and would venture down to the ground. These goats might end up in a more coastal region, and the females may sometimes end up in the water from gliding. This will make a pressure causing the females to become more aquatic. To avoid ground predators, the females may spend longer underwater. They might evolve to become predators. This would require them to get extra armoured scales to protect against fighting prey. They may become nocturnal, and evolve to use light to attract curious prey. The males might become larger, and start caring for young males when they leave the water. In order to protect the young males, they may use a loud roar to scare away predators. The females may evolve to huge sizes, in order to feed on larger whales and other large prey, as well as to store larger amounts of milk for their young. The young females may face predation from birds, and so might evolve to spray out reactive spit, that may evolve to become firey breathe.
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The continent of Enyvea is home to a diverse population of slimes. These amorphous creatures are blobs of viscous goo of mostly homogenous composition. In order to move, they draw magic from the background magical field and convert it directly into kinetic energy, propelling their whole body or parts of it in the chosen direction.
General info about slimes:
* The slimes are uniform in color, and their color is characteristic to the species.
* The weight of an average slime is 50-200 kg (assuming slime has the density of water), though there exist species as small as a tennis ball and as large as several tonnes.
* Different species of slimes can have different levels of intelligence, ranging from simple "eat anything" to as complex as humanlike.
* The slime can change its shape at will and assume any form it wants, though morphing into more detailed forms requires more attention and takes proportionally more time. Once the morphing is complete, sustaining the current form is significantly easier.
* Each species of slime produces a different set of digestive enzymes to digest its preferred prey.
* The slime converts magic to energy at a finite rate, and not fast enough to sustain levitation or movement at unnatural speeds.
* There are very few slime species which feed on magic, and for good reason: Most of the places able to sustain this niche are already overgrown by manaweed, a strange leafless bushy plant that does this better than slimes.
* Individual slimes can merge and split back at will. While merged, the merged individuals think like a hive mind.
How do the slimes move:
* oozing
* leaping
* crawling with pseudopods
* morphing into animal or pseudo-animal form (even as simple as blob on four legs) and walking or running
* morphing into a humanoid form and moving in a human way or similar
* any combination of the above
The senses of a slime:
* aura vision: The slime can sense the magical energies present in its surroundings. Magical objects and creatures look as if they were glowing, non-magical ones look dark, and the background magic is seen as a tinted fog.
* taste: The slime can taste objects with its whole body.
* smell: The slime smells its surroundings by absorbing chemicals present in the air
* touch: The slime knows where it is touching something, and whether it sticks to the thing it is touching.
* hearing: By sensing the vibrations travelling through its body the slime is able to hear its surroundings.
Species info:
The common green slime is an opportunistic omnivore. It is about the average size for a slime. Its translucent green color helps it camouflage in the vegetation. It cannot digest plant matter, with the exception of the fruits. It is fairly intelligent in terms of a slime, but not as intelligent as a human. It lives a solitary life, but can cooperate with others of its kind when the situation requires it.
Region info:
The forests of Én'vyen are the domain of elves and other nature spirits. No human ever dares to come here in fear of angering the fae. The dense vegetation makes this place difficult to move through. The center of the forest is so overgrown that the light barely reaches the ground. A diverse population of animals and magical creatures inhabits this place.
Fauna of the forest:
* The green dragon is the apex predator of the forest. It has an elongated body of length 25-40 m (from the tip of the snout to the tip of the tail), with four short legs and a pair of large wings. It has animal-like intelligence and poisonous gas breath. Females nest ontop the gigantic trees in center of the forest, laying one or two eggs at a time. While incubating the eggs, the dragon coils around them like a snake.
* The forest drake is much smaller than a dragon, measuring 2-3 m in length. It is green or brown in coloration and has a muscular, stocky build and a pair of short horns pointed backward. It nests in burrows at the outskirts of the forest.
* The yellow-eyed gremlin is an arboreal creature filling the same ecological niche as primates do in our world. It has rough hairless green skin and eats fruits, bugs, and other small animals. It has a flat face with upturned nose, large ears, and wide mouth full of numerous pointy teeth. It is very curious and often investigates unknown things without much thinking. It is known for its distinctive cackling and its glowing yellow eyes were the source of many ghost stories amongst the local folk.
* The batbirds are birdlike animals with many chiropteran features. They live in groups and different species have different coloration and body size. They have intelligence comparable to corvids. Their call consists of raspy 'car' and 'car-car' noises.
* The lizardmen are troglodytic humanoidal reptilians measuring 1.4-1.6 m in height. They live in tribes and are capable of coordinated hunting and making simple tools such as a spear. Their language consists of various short and long hisses. Some live a nomadic lifestyle, while the others dwell in caves. The females carry their egg with themselves, if they have one.
* The analogues of deer, foxes, boars, rodents, lizards, snakes and frogs also live here, as well as countless species of insects and other invertebrates.
Flora of the forest:
* The elvenwood tree is the largest tree of the forest, its branches are so thick that they can support a dragon nest. These trees are towering over anything else in the forest, especially in its center where they've grown much larger. The tree is pollinated by wind and its seeds resemble walnuts.
* The glowshade tree is a medium-sized tree known for its characteristic coloration. Its leaves are green to teal with dark blue veins and its branches have similar dark blue tint. It has very aromatic flowers and its small blue fruits are rich in mana.
* The manaweed plant is a dense-growing leafless bush that gains energy from magic insead of sunlight. It grows in large amount in the center of the forest, where light is so scarce that other plants have problems growing. It has small purple flowers glowing with magical energies and its dry seeds are in pods that crack open after they mature.
* The sylvan berry bush is a small thorny bush growing at the outskirts of the forest. Its juicy red fruits are a delicacy amongst animals of the forest.
* Several other mundane trees, which are of little interest to a slime.
* Miscellaneous grasses, ferns, mushrooms, and flowering plants.
Where and how would the slimes forage for food in such a biome?
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Since the slimes cannot digest plant matter, other than fruits, there are a few real world niches that could be taken advantage of in this biome.
You said the slimes have the same density as water which would allow them to control their movement through water very effectively. While there may not be many lakes or swamps in Én'vyen, many of the slimes might find it advantageous to sit and wait in bodies of water and "pounce" on animals which have strayed too close to the water's edge. This would fill a similar role to alligators in the real world.
Alternatively, a slime might find a fruit-bearing tree and simply wait under it while it's in season. Stretching itself out to cover as much ground as possible, the slime would slowly circle the base of the tree picking up any fruits it passes over or that fall directly into it.
Forest slimes are fairly intelligent, so they would probably not have a difficult time locating the burrows of a small animal, perhaps those of the forest drake. By splitting apart into several smaller slimes, the slime could cover each of the burrow entrances and simply wait for the animal to get hungry and emerge. Once one of the smaller slimes has caught a meal, it would track down the rest of itself and remerge.
A similar strategy to the one above would be for each of the smaller slimes to enter the burrow from all entrances and advance on the animals inside. The slime would rejoin itself at the center of the burrow and it will hopefully have found something.
A strategy animals could employ to avoid this attack would be to build a pseudo room in their burrow and after detecting the presence of a slime they would enter the pseudo room and fill the door with dirt, waiting until the slime disperses.
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Where: probably everywhere
How: any way you can imagine, and a lot more you can't.
For instance, I would expect at least one species to target dragon eggs. I would expect lizardmen females carry there eggs to prevent them being eaten. At the other end of the spectrum, I would expect some slimes eat other slimes.
Most slimes would probably target a small number of food types. One to three species of animals, or one to three plant parts. (I would not expect something to eat foliage, branches/trunks, and roots of one plant.)
Slimes might also be able to non-nutritiously eat some other things. For instance, a slime targeting dragon eggs might be able to eat/bore a hole up the trunk of a tree to surreptitiously reach its prey, despite not being able to benefit from eating the tree.
I would expect few slime species to be total omnivores, and those that are are probably very slow moving. A fast-moving creature that eats everything will quickly destroy its environment. (Earth has some starfish that are comparable.)
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From 2.4 to either 2.1 or two billion years ago, Earth underwent a surge in a waste product that we know as "oxygen". Before that, life thrived in an ocean rich with iron under an atmosphere loaded with carbon dioxide. This Great Oxidation Event has also been referred to as the "Oxygen Catastrophe" because for the majority of the extremophilic lifeforms of the Paleoproterozoic, this excess in oxygen proved to be a death sentence.
In the foreseeable future, the scientific community responsible for the study of alternate Earths had discovered that the ninth alternate universe identified doesn't have one Earth. Instead, it has **nine**--planets and moons that have a lot of the features that we'd find on Earth, like active plate tectonics, the exact size of the inner and outer cores, a strong magnetic field, to name a few. The sun they orbit is a red giant. Judging from its size and luminosity, we can confer that as of 2019, this sun has been a red giant for 542 million years and the Nine Earths orbit this star from seven to fifteen AUs away and may originally have been objects clashing between frozen water and molten rock while standing far into the frost line.
The first of the Nine Earths, orbiting the red sun from seven AUs away, is an Earth-sized planet that bears some resemblance to Tharn, one of the many worlds conjured up by Chris Wayans.
[](https://i.stack.imgur.com/bMo2D.jpg)
But looks can be deceiving. Its only similarity to Tharn is the amount of surface water--only 6% of the planet, averaging only anywhere between 30 and 100 meters deep. All of this alternate Earth's surface water is undrinkable, up to a dozen times more salty than our oceans. 79% of all its land is salt, indicating that when the sun turned red giant, it bore the full brunt of the transition and had the majority of its ice evaporated before proper melting could begin. In fact, atmospheric water vapor makes up 45% of this alternate Earth's water supply, which makes the overall planet so hot that it can't condense to form clouds.
Whether or not these next bits of detail would be relevant to the question, but the atmosphere also has high concentrations of salt and sulfur particles, reflecting sunlight off the atmosphere. If this were our Venus, it'd look as bright as the full moon on our night sky. A day on this alternate Earth lasts 48 hours and a whole year lasts 6,890 rotations. It spins on a vertical axis, so you won't find any seasons there, and the rotation itself is retrograde, meaning that the sun rises in the west and sets on the east.
Of course, the mad scientist community is not at all pleased with the discovery of the Nine Earths because the only life they all have are merely microbial, and they are simply not interested in boring old germs. Perhaps the maddest of them all is one Jonathon Pfeiffer, a known eco-extremist from Alice Springs. It was he who suggested that all of the Nine Earths should be terraformed so that he could dump in them all of "Earth's undesirables"--in his mind, all of the imprisoned and homeless people and the nonnative species of the world. To do that, he's going back in time, back to when the sun had been a red giant for only five million years (the length it'd usually take for a star to grow to that size.)
But terraforming this particular alternate Earth requires a particular improvisation. Since the surface water is hypersaline, his first plan is to colonize all of the isolated bodies with all the species of algae and cyanobacteria indigenous to Earth's own hypersaline body, the Dead Sea of the Middle East. His next plan is to revisit the planet 400 million years later to see how his photosynthesizers are doing. **Is this long enough for the algae and cyanobacteria to absorb enough greenhouse gas to cool down the planet to the extent of condensing the hypercharged water vapor into fully loaded rainclouds?**
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Cripes! Your mad scientist comes from Alice Springs. He'd know about saltbush. It's native to the Australian Outback. If he can do time travel, then breeding salt-resistant plants will be easy.
Why bother with 6% of the planet's surface. Seed the 94% of the planet's surfave with haline-tolerant plants. After 400 million years of a well vegetated world & you will have your Artificial Oxidation Event.
This answer assumes eco-extremists will know something about plants and salt resistance. Particularly, an Australian eco-extremist as salt contamination is a common problem in the Australian environment.
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I usually like to leave some wiggle room for myself when fleshing a concept out.
Dragons make that sort of impossible, same's true for nanomachines but ripped senators are a question for another day.
I was trying to expand my wiggle room by asking these questions:
[Would stronger tendons and bones allow for stronger muscles for the same weight?](https://worldbuilding.stackexchange.com/q/158303/32097)
[Would linear increase of a muscle's dimension increase the power as well?](https://worldbuilding.stackexchange.com/q/157610/32097)
The basic idea was that I had some wiggle room for material strength, thanks to graphene.
**The core idea was to reinforce the bones and the attachment sites to be able to handle more muscles. The range of motion depends on the length of the muscle, while its strength on the area.**
Staying aloft shouldn't be a problem for large fliers, thanks to thermals. Taking off, however, is a b...
Obviously, there would still be little room for the other stuff, like the third pair of limbs, but more managable than ~200 kg for this:
[](https://i.stack.imgur.com/A0NFp.jpg)
**Would it be possible for, say, a ~500 kg dragon to take off?**
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# Definitely possible.
The [Quetzalcoatlus](https://en.wikipedia.org/wiki/Quetzalcoatlus) has been estimated being 200-250 kg.
Also from Wikipedia:
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It doesn't seem too far of a stretch to say that evolution could have created something twice as heavy as the above examples, does it?
If the question is whether it is possible aerodynamically, the answer is a definite **yes.** Just look at how heavy airplanes are.
If the answer is whether that much weight could be supported in the air by muscles, the answer is still a definite **yes.** Just look at the [T-Rex](https://en.wikipedia.org/wiki/Tyrannosaurus)'s huge legs, and you'll see that the size of muscles seem to have little to no evolutionary limitations.
So, if large animals like these are possible, I can propose the following solutions to your question:
* Similar to an airplane, why can't you have a large animal that needs to run in order to take off? This animal could have evolved to search for mostly airborne prey, only landing in large open areas that allow them to watch for predators. Or they could be soaring animals such as the [Andean condor](https://en.wikipedia.org/wiki/Andean_condor).
* Having larger wings will allow them to have more lift, similar to the effects of a bigger sail on ships. (although a larger flying animal will also need other forces)
* Consider a dragon that has 2 sets of wings. These wings would work like a [dragonfly](https://en.wikipedia.org/wiki/Dragonfly), and could potentially alternate during initial takeoff and ease the burden of each set of wings.
Interestingly, to further the point about having a running start, [the following paper](https://jeb.biologists.org/content/215/23/4115) goes into how the wings actually have a "relatively small contribution" to the initial takeoff of birds such as finches and doves.
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@overlord has well established that it's reasonably possible for a 500 kg flying animal to exist. If nothing else, your 500 kg dragon could be a long-term soaring creature like an albatross, land only on prominences (cliffs and peaks) by preference, and avoid the need for a level ground takeoff almost all the time.
He needs to be *able* to take off from flat ground, though, because landing on the prairie or beach being a death sentence makes it hard to support a species that pretty well have to be carnivores (or at least carrion eaters).
There are sequence drawings, [perhaps even video](https://www.youtube.com/watch?v=CRk_OV2cDkk), of an ergonomically possible way *Queztlcoatlus* might have been able to launch from flat ground -- in general, it involves a sort of "pole vault" move, striding forward on the wing knuckles, then using the momentum with a stiff-legged "hop" to get enough height to unfold the wings and begin to laboriously flap to a soaring altitude. Obviously, the underlying requirement is that your flier needs to have the strength to climb by flapping, at least at a limited rate (it needn't have the performance of a Cessna, but that of a self-launch sailplane -- 40-50 meters a minute -- is about a minimum).
This climb performance is achieved with as little as 10 kW in sailplanes of similar mass, so let's say our (somewhat less efficient) super-Quetzl will need 15 kw. That only .03 kW/kg, which is pathetic for any living animal. Seems likely to work, given evolutionary pressure for such an animal to grow even larger than the known specimens...
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So, let's say there's a white dwarf star that has recently been born (by recently, let's say about 3 million years ago) Now around that time, a rogue planet, about the same size and mass as earth, came into the solar system and was pulled by the star's gravity, forcing it to orbit the star in it's habitable zone. Now, this rogue planet had frozen water all across its surface when it first came, but after it entered the habitable zone of the star its ice started to melt and eventually oceans were formed. Now, let's say after billions of years, life starts to develop and eventually it finds it's way towards the land. Now, if plants evolved on that planet, what colour would they be?
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**Interestingly enough, probably green.**
Plants don't need a whole lot of energy to function. If we ignore factors like the refraction of light in your planet's atmosphere, the radiation hitting your planet's surface will be far shorter in wavelength than that hitting Earth's. However, as found [here](https://en.wikibooks.org/wiki/Biology,_Answering_the_Big_Questions_of_Life/Photosynthesis), photosynthesis is all about capturing those higher-frequency electrons that are in the sweet spot of high energy, not destructive. **It's about finding photon wavelengths that are energetic enough to trigger photosynthesis and not cellular disintegration.**
You could say 'hey, my plants are extra-radiation resistant', but realistically your plants are only going to want those same red and blue photons. They may reflect some black body (which isn't in the visible spectrum)- outside of that, plants on Earth have no use for the more powerful UV rays that penetrate our atmosphere. Why would plants on another planet?
I'm totally open, however, to the notion of deep blue or black plants that use very high-energy photons in smaller amounts. Plants here need a balance of lower energy red and higher energy blue, meaning they reflect the super-average green. If your white dwarf is mostly emitting in <500nm wavelengths, then it makes total sense for your plants to move up the spectrum and try to get those UV and yellow photons, thus meaning they reflect the (now) super-average blue spectrum.
Hope it helps!
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On Earth, our atmosphere contains 78.09% nitrogen, 20.95% oxygen, on average around 1% water vapor at sea level, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Looking through this list not everything seems necessary for a habitable atmosphere.
* Nitrogen is needed by plants, but not in its gaseous form so supplying this rare resource which needs to be mined on Venus, Earth, Titan, from the depths of the giant planets or the sun vis water bound fertilizers seems more appropriate. **Nitrogen can go**
* Oxygen is obviously required for respiration on al level between 0.16 and 0.5 atm. In order to keep respiration easy and activity comfortable, I will keep it slightly below the Earth standard. **Oxygen is required**
* Water vapor is unavoidable in an inhabited section due to evaporation. **There will be water vapor**
* Argon is a product of radioactive decay. **Argon be-gone**
* Carbon dioxide is produced by animals and needed for plants. The Carbon dioxide needs to be taken care of either by scrubbers or plants.**There will be Carbon Dioxide**
Since any spacecraft is subject to the rocket equation reducing mass is always a good thing. While using a bare minimum atmosphere will only save minuscule amounts of mass any gram counts on a space vessel. Furthermore, lower pressure will reduce the amount of gas escaping into space.
**Thus my first idea is a pure 0.2 atm oxygen atmosphere for most spacecraft.**
I this plausible? NASA used a pure Oxygen atmosphere for the Apollo missions and it worked fine. Sure there was the [Apollo fire](https://www.encyclopedia.com/science/news-wires-white-papers-and-books/oxygen-atmosphere-spacecraft) but that happened in a 1.14 atm pure oxygen atmosphere so this is a different environment. NASA used 0.35 atm on the actual flights, but I don´t understand why they used so much pressure. Shouldn´t the chance of getting the required oxygen out of an Earth-like atmosphere with 0.2 atm be the same as getting the oxygen in a pure 0.2 atm oxygen atmosphere? Or should I increase my pressure to the NASA approved value of 0.35 atm?
**On space stations I would like to use an Oxygen/Helium atmosphere.** Helium instead of Nitrogen because it is dirt cheap since it is a waste product of the extensive Metallic Hydrogen, Helium3, and Deuterium mining operations. Nitrogen is expansive because it is harder to get and used for agriculture. The other advantages of Helium are that is light, seems to have no adverse effects of the human body and transmits heat very well (six times better than regular air) allowing me to achieve thermal properties similar to regular air with a lot less Helium. Of cause, there is the "Helium Voice" due to the much higher speed of sound in Helium, but that´s something one can get used to over time. The station air mix would be 0.2 atm Oxygen and 0.15 atm Helium.
Of cause, not all station and vessels in my setting these mixtures but they are the most economical and thus the most common. Nitrogen/Oxygen does exist yet is only used on planets and near planet stations.
**Are these atmospheres plausible? Did I mess up somewhere? Can this be improved?**
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First of all, your methodology is sound. Atmospheres are about partial pressure and setting up an in-ship atmosphere of around 0.2 to 0.3 ATM of pure oxygen is reasonable and actually practical; It means that your ship doesn't have as much differential pressure to deal with against the vacuum outside, meaning it an be lighter as the walls can be a little thinner. Of course, you still have to deal with debris strike or combat situations potentially, but if you're in an environment where that's likely you'd actually have the ship go vacuo instead and have everyone in space suits; That way, a hull breach doesn't kill everyone and send the ship off in strange vectors as a result of the gas venting.
Helium is an inert gas, so would work to 'thin' your oxygen on stations. Yes, everyone would have 'Alvin' voices but there are ways to remodulate spoken words for people in such an environment. But, what I'm not sure about (and have never researched) is if you even need the atmosphere to be that thick on a station. The Nepalese and Tibetan people seem to live in much thinner atmospheric pressure than we do for their entire lives with little difficulty, so I'm not sure if there are any long term effects to living in 0.3 ATMs of pure O2 for your entire life but it might be worth looking up. If not, then running your stations on the same mix as your ships would solve a lot of problems in terms of docking and the like when it comes to equalising pressure and extracting the helium for ship supplies.
Also, I know helium is used by the medical fraternity in MRI scanners, so I can imagine in an environment where there could be a lot of medical issues coming through the doors, doctors would love to get their hands on the kind of helium you can generate as a waste product and therefore would rather you bottle it than release it into the air as a thinner.
In short, your thinking is sound but the only improvement that I can see is that I'd be researching the idea of keeping your stations on a low pressure environment as well for simplicity and ease of docking, if it doesn't cause long term complications.
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You don't want pure oxygen atmospheres. For the ability to breathe, partial oxygen and carbon dioxide pressure is what matters. For fire, the worst danger in any enclosed system, the stoichiometric ratio of gasses is what matters, so a filler gas will prevent fatal accidents.
0.2 atm of oxygen may burn, while adding 0.8 atm of filler may inhibit a fire. The filler is not used up, so nitrogen can be used, Argon can also be considered. The filler gas can be considered part of the dry mass of the ship.
With helium as a filler gas could work, however you should consider that it may separate from oxygen in centrifugal gravity in any space where you don't have enough flow. Helium is also pretty good at diffusing through otherwise gas tight walls, and the squeaky voices will need to get used to.
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You absolutely need some form of buffer gas mixed with the oxygen.
In your case you propose Helium.
This will work, mostly.
However:
Helium penetrates everything. It enters your body's cells. It enters electonics. It enters pure chemical samples. It dissolves in even steel. And then un-dissolves itself on the other side, escaping your pressure vessel.
*Usually* the helium causes no problem when it ends up in the wrong place, it is a **very** inert chemical. But sometimes, it is an issue. Some electronics, some biological systems, etc. do not appreciate high concentrations of Helium.
There's a lot of discussion of this on the related question at [What would be the consequences of an Earthlike Planet retaining helium in its atmosphere](https://worldbuilding.stackexchange.com/questions/190251/what-would-be-the-consequences-of-an-earthlike-planet-retaining-helium-in-its-at/)
Plus, of course, everyone will SOUND LIKE CARTOON CHIPMUNKS!
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A planet recently discovered was explored and proved unworthy of terraforming: It is mostly made of carbonaceous minerals, classifying it as a **carbon planet**. However, one of the explorers does not see that as a hurdle. He seizes the opportunity to mine the abundant carbon and build space elevators using carbon nanotubes fibers. The space elevators will serve to hold-on a sheet made-out of carbon fibers as well. This sheet is the foundation for the "flat earth". The setup looks like this:
[](https://i.stack.imgur.com/N1Sa2.jpg)
The image is not to scale, and the number of "ropes" holding the basket to the surface of the planet is not final. The idea is that the basket spins along with the planet. The content comprising the atmosphere, water, soil and biomass is held-down to the surface using the centrifugal force. The flat Earth has rims which serve as the walls holding the volatiles on the surface. **edit: This is a side-view. The basket is a disk with rims holding the atmosphere.** The anchorage points to the basket may serve as anchorage as well as mountain tops, therefore simplifying engineering issues. Each anchorage point is connected to several distant points on the planet's surface. This setup should prevent the basket from "folding" and spilling volatiles into outer space.
At its final state, the planet will serve as a "moon" to the dwellers of the flat Earth. It will, however, remain at the Zenith and will only change phases along the day/night cycle.
So, is my setup stable enough? Will the surface remain flat, or will it bend and fold? Assume there are enough "ropes", and planetary "anchors" are sufficiently massive to avoid being lifted away.
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**This is a clever idea**
*There may be enough science to prove this wouldn't work, but I don't think that should matter. It's a clever idea, and clever ideas make for good stories.*
One of the reasons why space elevators are thought to be stable is that the terminus of the elevator is far enough away from the Earth for the centrifugal force caused by the rotation of the Earth to overcome the Earth's force of gravity.
* An argument could be made that this works for space elevators because we're basically dealing with a single connection point on Earth. The moment we introduce two or more we introduce instabilities due to a thousand variables including the natural stretch of the material due to stress, temperature, local gravity, etc. I counter with the use of substantially beyond industrial grade computer-controlled winches, designed to tighten or slacken individual cables to (a) keep the platform stable and (b) keep it at an average distance from the Earth. Besides, their existence introduces interesting sub-plots to the story. (Like an anti-flat-earth religious movement that sees the platform as an ecumenical threat and decides the winches are the weak spot!)
* Centrifugal force would cause the center of the disk to bulge away from the planet. Gravity would cause it to bulge toward the planet. That would likely cause a lovely standing waveform oscillation that would make everyone seasick and eventually destroy the platform. However, I could imagine designing the platform perhaps like an optical lens, thicker in the middle, to minimize this behavior. (Or the inhabitants get used to being seasick because, like very tall buildings built to withstand the sway caused by wind, the platform is simply built to withstand the flex. Might be an interesting source of power, like ocean currents....)
* Your biggest problem (and perhaps the biggest argument against this being scientifically practical), is that your cables keep the platform from winging off into space, but they don't keep it from tipping. Generally, you're relying on centrifugal force to stop that from happening, but what if a meteor (or a new teen driver) hits the platform, space-side, on the edge? How much force this would take would depend on how far away from the planet the platform is (increasing centrifugal force). Living on the underside of the platform (looking at the planet, which makes the day/night cycle really complex as you'd only actually see the sun during — from the planet's perspective — the twilight periods of morning and evening. You'd have reflected light during planetary day and no light during planetary night. That would be so weird....) However, no matter how far out the platform is, there will always be an impact force causing it to tip. You could use rockets to recover, or possibly those winches, but you would need something. (The problem with the winches is that the only way they could recover would be to pull the other side of the platform closer to the planet in an effort to right the tip... pulling the platform closer to the planet isn't necessarily the *safest* thing to do. If they succeeded in righting the platform before the critical "fall to the planet's surface is inevitable" point, then they'd need to gently reel out the cables.)
* Finally, your cables would not be capable of stopping the platform from *twisting.* I think this is the least likely issue, but it's worth bringing up because once it started twisting (rotating around a center perpendicular to the planet below) the cables would act like springs and you'd have the devil of a time getting it to stop. Once again, rockets, but that seems inelegant. The winches might help. It's worth thinking about. A geologist or climatologist would need to confirm my next statement, but I think the Coriolis effect1 of the planet would naturally induce the twist, making it something you'd need to plan for (bear in mind I'm expecting you to cable the platform in 3D).
*BTW, you'll want to use a circle, not a square. The corners of a square make the math needed to correct for the things I just discussed a blooming mess.*
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1 *John Dvorak points out that I'm misusing the Coriolis Effect in this instance. I haven't had a chance to go read up on it more, so bear in mind that this application is likely in error.*
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**Proposals.**
1. Your basis is not a carbonaceous planet. It is a large alien spacecraft of some sort that was found adrift. It is badly damaged and has lots of weird stuff inside that no-longer works. Human engineers managed to hack two engines. With those engines they can spin the spacecraft, really fast and now that is all this spacecraft does. No-one wants to be on this spacecraft when it is spun up to the speed necessary to generate gravity-like centrifugal force on the flat world. A robot is in charge of the spinning engine.
2. Your flat world is tethered to the spacecraft as you propose. It is much larger than the spacecraft. The combination is asymmetric and does not spin well. There is a solution.
3. A second flat world is tethered opposite to the first. With two flat worlds and the alien spin engine between, it becomes symmetric, like a centrifuge, and a doable deal.
4. The blue flat world and the green flat world have sports teams that play each other. People get very passionate.
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This is basically an engineering problem.
But a very extensive engineering problem. With a lot of equations and variables. An entire TEAM of engineers engineering problem.
To work, the station has to be geostationary. That pretty much determines how far above the planet it would have to be. The rotation speed of the planet determines the speed of the station, and thus the centrifugal/centripetal gravitational forces, and thus how effective they would be in creating some form of artificial gravity. For instance, geostationary satellites around the earth are not known for their artificial gravity, given the rotational speed of the earth.
The stiffness of the platform is completely engineering. I posit that it would be made with a concave (convex?) shape, so it would 'stress' back into a flat shape.
I am not sure if there is any need for cables to 'hold' the platform, if the planet was large enough *edit and if the platform had its own propulsion system*. Gravity is the 'cable' that holds satellites to the earth. To spin the platform fast enough to require cables, (i.e., that it needs to spin faster than the calculated speed to hold it in orbit to balance the centripetal/centrifugal forces and the gravitational force), the platform would have to be spinning at a substantial speed, much beyond the escape velocity. If it were *edit* *active* geosynchronous, the planet would have to be spinning at the same speed. A cable to hold it would then become a materials science problem. It could be that the required thickness of the cable becomes greater than the diameter of the platform, if the goal is to spin the platform with enough speed to create anywhere near earth-normal gravity.
**TL:DR**
But the really big problem would be, that the planet would be spinning at such a high rate that anything on the planet would be spun off the surface. After all, we have already established that the spin of the planet imparts a velocity that is greater than the escape velocity of the planet itself. That is the only reason the tethers to hold it would be required in the first place.
And the space elevators would have to provide the power to bring things DOWN to the planet, not to lift them off the planet.
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How do you go about building a working Earth-like ocean ecosystem from scratch in Europa's subsurface ocean?
On Earth, abyssopelagic species have evolved to live more than 6km below the surface. Although Europa's ocean is estimated to be up to around 200km deep, hydrostatic pressure at the seafloor would be 130-260 MPa, corresponding to 13-26 km depth of a theoretical Earth's ocean. The water beneath the ice shell is stirred by vigorous thermal convection, with heat flow at base of ocean about 8 mW/m2.
Assume that we can engineer abyssopelagic Earth life to handle these depths and Europan temperatures as a result of a culture employing advanced, but limited, genetic engineering and biotech.
Assume that oxygen levels are abundant, and that Europa's ocean is absent complex life beyond a microecology of archaea-type organisms clustered around thermal vents. These organisms may offer some adaptive advantages that can be spliced into Earth life introduced to Europa.
Salinity is handwaved with nanotech. Acidity can be regulated by adapted Earth organisms such as Haloquadratum walsbyi, Noctiluca scintillans and Rimicaris hybisae which prey on (Noctiluca scintillans) or coexist with (Rimicaris hybisae) Europan archaea-analogues.
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The Earth has some excellent examples of ecosystems that thrive on the underside of sea-ice in the polar regions. Convection in the Europan ocean could conceivably bring nutrients up to the base of the glacial crust, which could be exploited by modified organisms that cling to the underside.
<https://www.awi.de/en/focus/sea-ice/life-in-and-underneath-sea-ice.html>
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If you are looking at advanced life yes you could look to animals and plants close to undersea ice.
However more simply you could start a bit closer to abiogenesis - ie. simple bacteria and other early lifeforms. These are everywhere, every nook and cranny of the Earth, even deep in ice sheets in thousand-year old glaciers.
To furnish Europa with an ecosystem, all you likely need do is to not sterilise a rocket, and crash-land it on Europa. The bacteria and other micro-organisms on the spaceship will eventually float, spread and colonise the undersea ocean. It may take a long time, however eventually more advanced species may evolve once the initial bacterial spread reaches all undersea niches.
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In many countries, stipulated term criminal sentences (i.e., not indeterminate or "life") can be extremely long, well over a hundred years. The US is one well-known example.
Assuming all other things equal, I'm trying to base an idea around the realistic impact/fallout/events would be, flowing from a notorious US prisoner guilty of some hideous crime, simply failing to die after a reasonable number of decades, and with his/her prison term coming close to completion.
But this is a situation that's never arisen - such prisoners are implicitly assumed to always die in prison, unless pardoned, so I'm having issues figuring which way(s) the public fallout would go, once any posturing and untenable claims of what some politician will do, fall away, and public bodies and individuals have to start treating it seriously.
To give some flesh to the context:
* The prisoner was unambiguously guilty of some heinous crime(s). Could be murder, kidnap, arson, probably notorious or multiple. Think about cases like Manson (US), the Moors killers (UK), someone who pleaded guilty and took 150 years without parole, in return for not seeking death, and where the public sentiment is "never freed, over my dead body" even decades later.
* They've now served 138 years of it, and by the calendar are about 170 years old, but show no sign of age related loss of faculties or condition. An informal interview with their lawyer elicits the statement that they are looking forward to enjoying life again and making up for lost time - whatever that ambiguous statement means.
* Some people are intrigued. Others scared and demanding "something be done!"
Nobody really understands, and the prisoner either doesn't understand the reason themselves, or in any case refuses to discuss or give any consent to investigate while locked up. Its not even clear what their lifespan might be, and none of their deceased or distant living relatives seem to share this anomaly.
I'm a bit stuck figuring what realistic reactions might be, from today's executive and justice departments might be, or the prison service, if this happened. I imagine they would make statements about ensuring public safety and also note they can't do much - but as pressure grows and the situation gets a higher political profile, and senior political/departmental careers start to be on the line, we can expect more serious thought on it - but what would that be likely to comprise?
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So I'm sure this sort of thing would make the news long before the convict's sentence was up, since people living to 170 years old is unprecedented. What's worse, is that as the decades go on, and the convict refused to age, people would get more and more apprehensive about it. Probably as the prison sentence was coming to a close people would start to get up in arms about it, calling for the sentence to be changed to indefinite and so on and so forth.
Assuming that these outcries for a sentence change went unanswered, and the convict was let free, he would probably be assassinated shortly thereafter. Think of JFK's assassinator Lee Harvey Oswald. He was shot and killed by Jack Ruby before ever making it to trial. I wouldn't be surprised if someone took "justice" into their own hands after the convict was released.
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**Just let an inmate kill him**
Have inmates kill the criminal for you. Just hire a lifer to do it, no fuss no worries just clean up after them (theirs even been cases where this has happened) hell it won’t even cost you much. Pay could include, less time on their own prison sentence, give them cool items like a TV or exotic foods (for prison anyway), or let in some contraband for them to enjoy. When you are a lifer you will do all most anything to change your circumstance even kill for it.
Unless his immortal but then you will have bigger problems
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I work in a prison, I think I can give some insight.
**Specific Wording Of the Sentence Matters**
So a life sentence carrying the phrase "without parole or the rest of his natural life" is pretty binding. It means that as long as his heart is beating and he is breathing that his sentence is in effect. Thing is...
**Lawyers Exist**
Short of a very solid life without parole that cannot possibly be appealed he is probably going to appeal. Also his lawyer can argue for various suspensions, reductions and what not. The crimes lose their sensational effect with the public, the victims die and the families move on. Given enough time the people harmed and society as a whole forget, and lawyers are able to appeal for reduced sentencing and for assorted other things like the possibility of parole and whatnot.
**Legal Precedent Does Not Exist**
A guy turning out to have a lifespan of well over human norm has never been given a life sentence. A lawyer could very successfully argue for a guy to be released or at-least extended the option of parole by pointing out that locking a man up for 2 centuries or more constitutes cruel and unusual punishment. What's more, he could argue that the proof his client even committed a crime no longer exists. If somehow successfully granted are-trial or in an extensive appeal process it would become increasingly difficult for a prosecutor or a parole board to push for harsh sentencing. For a parole board to deny parole they need to be able to demonstrate that releasing the inmate would cause harm to the community, and distress for the victims and survivors. If there are no victims or survivors to come in and argue that he needs to stay locked up that route is gone. Plus 138 years is a long long time, the society and community that he harmed no longer exist. 138 years ago cowboys were still shooting it out with Indians on horseback, the probability that evidence survived all that time is pretty low. This means nobody can even prove that a crime occurred in the first place. Lawyers **live** for this stuff, it couldn't get more easy for them to get him off or at-least get him parole.
**Summary**
He's probably going to end up being released, if not for a sentence served then most assuredly with a successful parole hearing. I cant exactly explain what happens to him once he's out since he's a medical mystery that possibly represents billions in medical research, but the idea he would remain locked up indefinitely is probably not very likely.
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If we look at this from a pure legal point of view, they'd have to be released when their term in jail is up. But most politicians wouldn't need to worry, protecting personal rights is a very hot button issue no matter the time period, so ensuring the criminal was released at the appointed time would probably be favorable to a solid 50% of voters, landing him a net equal effect in his vote.
But on a individual level, vigilante's who think the prisoner deserves death may attack as soon as he's released, or even before hand. I can imagine a riot in which people invade a prison to get him.
Or even before that, a guard or group of gaurds may decide to be executioners for the day. If I was in a position of power and this scenario was happening, I might even encourage the warden to put guards who might go "to far" near the prisoner, if not straight up appoint guards to kill him before his term ends. Of course I'd do it a couple years before the end of his sentence as opposed to just before the sentence ended, so it looks at least slightly less like government subterfuge.
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I'm building a very small homeworld (0.602 M$\_e$) with a very large moon (0.0711 M$\_e$) that orbit each other at a barycenter about 7.12 planetary radii (1 R = 0.870 R$\_e$) from the primary's center; 52.08 R from the moon's center. I'm trying to get a realistic model of geological activity on both worlds, and I was wondering how much tidal flexing would play into the vulcanism, seismic activity and average temperature of the primary in particular. There is [one other article](https://worldbuilding.stackexchange.com/q/61059/47857) on here that I've found that might help, but I can't make heads or tails of it!
Is there anybody who might be willing to walk me, a lowly music student, through it? Cheers and thanks :)
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# Model tidal heating by comparison
### What the equation actually means
I don't think that attempting to solve the equations to calculate tidal heating is going to get you anywhere useful. Instead, I think you should estimate tidal heating by comparison with known objects.
To boil down the first equation in the linked answer to just the variables:
$$E = R^5n^5e^2\cdot constants$$
where $R$ is the radius of the secondary, $n$ is the mean orbital motion (average velocity of its orbit) and $e$ is the eccentricity of the orbit (of the secondary).
The tidal heating in the secondary depends on the change in gravitational force from the primary over the course of an orbit. If the secondary orbits faster ($n$) or has greater motion to and away from the primary ($e$), then the tidal forces do more work pulling on the planet, increasing the tidal heating.
Ultimately, the force that matters is the force of gravity of the primary on the secondary. [Mean orbital motion](https://en.wikipedia.org/wiki/Mean_motion) is given as
$$n = \sqrt{\frac{G(M+m)}{a^3}},$$ where $G$ is the gravitational constant, $M$ is the mass of the primary, $m$ is the mass of the secondary, and $a$ is the semi-major axis of the orbit. In most cases , $M >> m$, so we can drop $m$. Then we can look at the comparison between mean orbital motion and the [equation for gravity](https://en.wikipedia.org/wiki/Gravity#Newton%27s_theory_of_gravitation). With this comparison we can see that $n^5$ from the tidal heating equation is roughly equal to
$$n^5 = \left(\frac{F\_g}{m\cdot a}\right)^{5/2}.$$
The takeaway here is that, ignoring orbital eccentricity, the energy of tidal heating is proportional to
$$E \propto \frac{R^5F\_g^{2.5}}{a^{2.5}m^{2.5}} $$
### Comparisons for your system
To get an idea of the magnitude of these forces, the force of gravity of the Earth on Luna (i.e. our Moon) is $1.98\times10^{20}$ N, and the mass of Luna is $7.35\times10^{22}$ kg; the radius of Luna is 1734 km, the semi-major axis is 384,400 km. Combining these according to the proportionality equation above gives a 'score.' To make the number more tractable, we'll take the log base 10 of that score, this will show us how many orders of magnitude apart various tidal heatings should be. The log score for Luna in the Earth-Luna system is 50.8.
For an example of high tidal heating take Jupiter's force on Io; the force is $6.36\times10^{22}$ N and the mass of Io is $8.93\times10^{22}$ kg; radius is 1822 km, and semi-major axis is 421700 km. The log score for Io in Jupiter-Io is 56.9. This is six orders of magnitude more heating that Luna gets! No wonder Io is so volcanic.
For your listed problem statement, the force of gravity from the moon on the planet is $9.46\times10^{20}$ N, while the mass of the planet is $3.60\times10^{24}$ kg. The primary's radius is 5542 km; while the semi-major axis around the barycenter is 39464 km. The log score for your primary is 50.3, just a bit below what Luna is getting from Earth.
Note that Luna does not have a molten core, volcanoes, or anything else exciting that might come from tidal heating. Therefore, I conclude that the planet in your system will not be appreciably tidally heated.
### The effects of oceans
The [Love number](https://en.wikipedia.org/wiki/Love_number) is a parameter that measures the rigidity of the body, and thus the amount of energy that is transformed into heat by friction when the satellite is flexed by tidal forces. For the Earth, the Love number is relatively low, because of the oceans. You see, much of the energy of the moon's tides is used to move the oceans. The oceans do not generate very much heat when they are worked, because they are a liquid and the molecules easily slide past each other. On the other hand, rocky solids or even highly viscous liquid magma generates much more friction when it is acted on by a force.
# Conclusion
Tidal heating of planet by its smaller satellite is insignificant. Even with the maximized conditions in your problem statement, tidal heating won't even reach what the Earth's (geologically dead) moon is getting. Consider that this heating is spread out within a planet two orders of magnitude more massive than the moon is, as well.
Also, having a liquid ocean on your primary won't help matters either.
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## Background:
I am working on a super soldier transhuman/posthuman concept for my fictional world. It takes the base human genome then uses genetic engineering to augment, delete, enhance, add, and otherwise modify the resultant creature. I am aware that genetic engineering is mostly speculative at this point but would like some imput on various ideas in my head.
Specifically I am working with the idea of a super soldier who is designed to look a certain way (either as a standard model "clone" or a specific design choice by their designers).
Because humans who are athletic, fit, and active tend to build muscle, grow, put on weight or otherwise change shape and deviate from their pre-athletic selves (assuming they are well-fed) I was wondering if there was a way to limit physical changes that accrue from physical activity to keep them looking like their intended original design despite the physical activity they engage in.
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## Question:
**Could genetic engineering alter a human body's myostatin production to inhibit excess muscle growth beyond a certain pre-set point?**
Specifically could someone's body be designed in such a way that they cannot build excess muscle. They could train and perform athetic feats, their muscles would tear and reform, but because of the presence of [Myostatin](https://en.wikipedia.org/wiki/Myostatin "Myostatin") they would reform "exactly" the same size/density of muscle as before and thus so long as they eat enough to maintain their peak form, they would not go over that genetically programmed limit.
In essence I am pretty sure there is a limit to how large muscles can grow in humans, and was wondering if genetic engineering could artificially set a specific limit to give a human a certain desired look despire how much physical activity they do.
I would like to stick to hard-science, but given that genetic engineering is in its infancy, I understand some things are speculative.
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## Additional Info:
The following are additional thoughts and ideas that come to mind related to the topic. They are possible future questions, but not the main question of this post.
I have read in several places, about the opposite effect being present in nature. Two examples that come to mind are the [Belgium Blue Cow](https://en.wikipedia.org/wiki/Belgian_Blue "Belgian Blue Cow") and the [Bully Whippet](https://en.wikipedia.org/wiki/Whippet#Health "Bully Whippet Health") dogs are prime examples of repressed or lack of myostatin.
They are discussed in this question another user asked:
[Humanoid Race with Surpressed Myostatin Gene - Appearance?](https://worldbuilding.stackexchange.com/q/79688/47490)
Another reason for my question is to see if it could be genetically engineered such that two identical twins, one who is very athletic and sporty, and the other who works out often but only lightly, could still end up with the exact same build, because both were at the peak of this artificially imposed muscular cap.
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## Previous Related Questions:
[Celebrity Super Soldier - How Strong Could a "Realistic" Humanoid Be Designed to Be?](https://worldbuilding.stackexchange.com/q/104167/47490)
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One of the closest real world analogies I can think of is the breeding of dwarf plants by Norman Bourlag in the green revolution. Yield was increased by effectively genetically capping the height of plants so they didn't fall over when they had x amount of grain. The obvious trade off though is that energy had to go somewhere, so instead of energy going to plant height it went to grain production. So it is possible (in plants at least) to genetically effect where energy gets utilized in growth. Plants also have a mass of undifferentiated cells at growing points, meaning that until signals are sent, they don't know what kind of cell they will be (stem, leaf, chloroplast, etc.) which are effectively stem cells. If it were possible to control which signals these cells recieved, you could control exactly how much leaf material was produced, then shut it off and turn it to say stem production.
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I'm designing a story where I'm taking current situations and trends such as market and cultural globalization, massive state debt and constant corporate mergers to a semi-dystopian extreme in order to build a fictional world where:
* Newly created private companies almost automatically become part of one of four conglomerates. These four complement one another in different ways, and there is a fragile equilibrium where this status quo benefits all of them financially. Each of these multinational corporations have various enterprises related to basically every target audience (young, old, rebellious, conservative, etc.) in basically all areas (consumer goods, industry, media, etc.). If the newly created company has been created with the intention of being independent and tries to avoid being merged into one of the bigger fishes, for instance, all competition can band together (or maybe just one of them will need to act) to lower prices even into a loss, which they can allow temporarily as they're part of something bigger, so that the new actor's market share and its profits are negligible or at a loss, and the debt will require them to accept being bought off (this also will bring all of the infrastructure into the hands of the buying conglomerate).
* Government is libertarian, so there are not anti-trust regulations to avoid these dirty tricks. In fact, many of the government members have work experience and close contacts in the higher ups in one or various conglomerates (and they will presumably go back to one of them after their "public service" office terms are over), so the "state" has become a market tool progressively, without need of anything as overt, suspicious or obvious as a coup. Political options such as the traditional left or the far-right have dissipated, given that there's not enough media traction for them and, when they do appear on the news and talk shows, it is to be demonized and ridiculed.
* Society elects these representatives because rampant consumerism has ended up ended up replacing ideology and nationalism as a point of pride; as in, people don't feel pride for a country, they feel closer to cultural products and notable people of the four corporations. The lynchpin of conservative traditional family values has, say, become a certain TV show focused on Aesop's and pat morality, while a center of post-modern cynicism is a satirical TV show... maybe aired in two different channels but part of the same conglomerate. Whatever citizen outrage exists is fed back into the capitalist machine. Of course, there exist some small grassroots movements, but they don't get much traction outside of performances, and even some of its members (the ones whose antics get the most attention) end up being bought off by the media in order to participate on it (see the ending of Black Mirror's 15 Million Merits for reference).
So, apart from asking you to find holes in my worldbuilding (please do), here is my main question:
**Is there any relatively plausible way to "end up" like this? I want to explore the progression from the present to that situation somehow in the story... Which are some possible, crucial events that could have shape the society I explained?**
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How does this differ from the current world? The critical differences seem to be
1. No antitrust enforcement.
2. Weak geographical loyalties like nationalism and belief-based loyalties like religion.
The latter is already becoming true. People are moving between countries at higher and higher rates. Religious affiliations of none or unaffiliated are increasing. So you can just extend current trends.
The former is different per country. Some of the larger economies, like China and Japan have weak antitrust already. The US varies between periods of strong and weak enforcement. Also note that companies can evade restrictions through organic growth. Google, Amazon, and Facebook are quite dominant in their areas. Network effects are already reinforcing the advantages of large companies.
All you really need is to come up with a reason why China wins. For example, China could be become the new US. Using a mix of corporate, development, and military aid to bind other countries closer to it. Chinese corporations expand from China to Africa, South America, and Southern Asia. I don't know that that is what will happen, but it is at least a plausible story line. It's what some people in China are trying to make happen. Maybe they're right that they can.
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Short answer: Lobbying
Long answer:
It would take a long string of lobbying to find/build loopholes into anti-trust laws. The only reason for an oligopoly to develop is if they are prevented from forming a monopoly. So, I envision a long string of small events where they use the oligopoly to "prove" that they aren't a monopoly. Once the system is set up and the 4 power bases are stabilized, they can begin the process of getting the public to forget about monopolies (or keep it, dealer's choice).
The would always need to have something to point to that is worse than the current system so they can harp about "how good we are compared to...".
Note I would study Japan for the way conglomerates can work. Honda and Toyota make a whole lot more than cars. We just don't see it in the US. They also have non-confrontational unions.
So, a system that you are describing can work. It will just take a long road to get it to work in the US. I would say 2-3 generations of concerted effort.
Here are the ways that a small business would be "absorbed" by one of the four:
* Small business cannot get product manufactured or marketed for a
decent price so the license it to one of the four for an upfront and
a percentage. That is done today.
* Small business needs a loan from one of the four, gets deal if uses
that conglomerate's parts to build their widget and a deal to use
that conglomerate's marketing form to advertise and that
conglomerate's retail outlets to sell it. Now, how independent is
that small business? If the deals are good, the conglomerate gets a
bunch of products that they do not have to innovate and do not need
to manage but leave only enough profit from the entrepreneur to make
it worth the effort. If the deal isn't as good, then it just pushes
the licensing. That happens a lot today just not through a single
conglomerate.
* The public is sold on the idea that they can only trust the safety or
quality of a product if it is made by one of the four.
* The four make sure the business fails and then just make the product
themselves. This is the least efficient, I think.
I really don't see the four buying small businesses much unless there is good management in the business.
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**What medical problems might a resurrected person have that would be annoying but not completely debilitating, focusing on the joints and bones specifically?** Yes, this is a magic world, but I want to do things that do make sense, in some way and track logically if at all possible.
There are lots of sci-fi & fantasy genres which feature resurrection of a dead character, whether through science or through magic, but often (and especially in video games) there are no side-effects to being res'd.
So, as part of my world, I want to have dead people be alive again (not necromancy, actually alive, with all the things that normally come with that) but I want to make sure that there are consequences for being res'd--and not just losing all your stuff or it being expensive--but actual medical problems as result of the process. There are lots of different flavors of medical problems they can have, but I thought I would focus on a particular area (joints & bone) and see what y'all might come up with, considering that:
* Bones fall apart pretty quickly. Does this mean that there are more joint issues the older the corpse is?
* Bones might lose something that they can't regain quickly after the process, which may explain why there are problems
**How it works:**
Several people have asked how this works in my world, so here's a little background, in case you need it.
You have to have all the skeleton or the dust representing the skeleton for all the parts to come back. If an arm is cut off prior to death, as long as you have the arm bone, along with the rest of the body, then body is knit back together with the arm. *Flesh, blood and organs can be missing, but will be restored completely. Bones or the components for the original bones (like bone dust) have to be present in order for them to be rebuilt.*
The bones in this particular magical world are the framework/structure. They are more important than all the other stuff and can't be replicated--they are needed as the component for a complete rez (you'll see this in other magical worlds, where you just need the heart or whatever). Also, **there are lots of other problems that could come from organs, but I am focusing on the skeletal system, to narrow this question & because it is so important to the ritual.**
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Starting with the OP's proposition that resurrection requires the whole skeleton of the person to be resurrected, it seems reasonable, that irrespective of age, that the body can be restored to a viable form. In this case, a viable form means a living, breathing human being. The sort if you ran a sword through their gizzards they'd die all over again. And need to be resurrected again. Or is more than once cheating?
This suggests that if your resurrection persons performed their dark arts on, for example, a thousand year old skeleton that flesh, organs and other tissues will be brought back into existence around the bones of the skeleton.
This in itself, suggests one possible problem. Namely, that the bones will need to be carefully arranged in their proper positions for the newly resurrected body be correctly constituted. No-one wants their fingers or toes on backwards, But considering the OP said resurrection was possible even if only bone dust remained, this suggests the bony fragments will rearrange themselves in their correct anatomical locations and positions during resurrection. If not, the results might be an anatomical mess. Perhaps the resurrection reconfiguration might be a normal part of the process, but the right results aren't always guaranteed. This could be problem number one: bits not in their right places and the attendant problems to go that those issues.
The OP has specified that not all the organs need to be there. This would lead to no end of medical issues for any resurrected person. They could easily range from the merely inconvenient, through the absurdly embarrassing, to the down right life threatening. Heart or liver missing! Oops!
Details of the resurrection process made no mention of how effective this is on resurrecting the bones and skeletal structure itself. If bone dust can be used for resurrection, hopefully the resurrectee won't end up with a pulverized skeleton. Dust instead of sold bones to keep everything held together. Also, the strength of the skeleton might not be restored to what it was in its previous life. Osteoporosis might be the bane of resurrectees.
Falls that easily break bones might be a constant problem. That also means staying out of sword swinging fights or bar room brawls.
This answer assumes any problems with joints and connective tissues adhering to bones and skeleton will be of the same order as missing organs, tissues and other fleshy bits. Although what may be of more concern is whether bone marrow can be resurrected to its full, proper function. This is the source of blood cells and immune factors. There could be ongoing problems with infections and a variety of blood conditions. Immunodeficient resurrectees could have lots of health issues to cope with, this means they effectively would suffering from leukemia. Not necessarily, it's most severe forms, but there are milder forms of the condition that present major health risks. As the author of this answer knows, having lost a good friend to such a condition.
Because this osteoregenesis process of resurrection is magic-based, it is difficult to determine its full limits, except in a speculative manner, for example, a powerful enough magic could overcome all possible defects and deficiencies. The OP would be advised to construct a set of rules governing this resurrection process. This will make it more tractable, orderly and conceptually well behaved. For example, the limits related to the age of the skeleton (from time of death). The probability of resurrection succeeding based on the percentage of bones available. The effects of bone dust as this could be more efficacious than whole bones. Pulverizing bones might be an additional magic art with its own guild of practitioners. Whether having available sufficient flesh will aid or hinder of a successful resurrection. Indeed, make up your own rules to make resurrection lawful and well behaved. Also, you can build in the rules you need to lead to unwanted medical side-effects and other possible conditions.
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Well, as far as decomposition goes, it depends on how "alive" you want your zombies to look. If you look at a forensics decomposition chart, you can decide how long the body can sit before it is impossible to revive. Does it have to be within the first minutes after their heart stops beating (fresh stage), or when the body starts bloating? Say you decide their body has to be revived within the first 48 hours. Will their body continue to decompose? If so, then they have a time limit. In a hot climate, it can take only 2 weeks for a body to be reduced to skin, cartilage, or bones. In a cold climate, the process can take over 2 years. Anyway, if you decide that the resuscitated don't decompose as they continue to "live", I think a time limit would still be beneficial, because then your character gets faced with a tough moral question: Is it worth it? Living another 2 months, years, etc. Or are they alive forever? Watching loved ones die? What if only certain people could be revived, so revived people don't necessarily get to live with loved ones. Where are the skeletons on the social ladder? Are they above normal people, or below? Do they need any basic necessities? Are they forced to get jobs? Does what the skeletons died of- does that effect their health after they are revived? Are normal people afraid of them? (Religiously, do people still believe in reincarnation?) Do the skeletons get shunned and form their own towns/society? How would this function, especially if they don't need food?
I could go on and on, but hopefully this helps you form your story :o)
Good luck!
Madeline
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Need ideas for the evolution of the kumiho, the Korean nine tailed fox that is native in the Korean peninsula.
First of all, this species is sexual dimorphic so both sexes would look different from each other both in appearance and maybe their mode of early life before forming a pack.
While the vixen resembles a red fox, the dog fox resembles the north American coyote in shape and size (except retaining having some cat-like features like other foxes) with stronger jaws to grip on struggling prey.
Here it fills the same ecological niche as the coyote.
Like the gray wolf, this species form packs to bring down larger prey such as deer and wild boars.
As lionesses do the hunting for the pride, the male kumihos (not the vixens) do most of the deer hunting (due to their size and shape not to mention being stronger than the vixens) as well as patrolling their territories and keep rival packs and predators at bay .
I haven't thought up of some roles for the vixens yet.
And finally, the alpha pair have longer tails (the extras being massive dreads of matted fur that function like a bird's tail feathers) than other individuals in the pack which is used as a form of hierarchy in the group.
While the relatives of the kumiho use their tails use their tails which are marked with iridescent markings to both attract mates and to intimidate predators. Since the kumiho is a pack hunter therefore mate for life instead and display would be a one time thing so might need ideas on the concept of the tails of this certain species.
By the way, don't worry about the tails as I've already thought of ideas for the growth and development of the tails as well the use and how they function.
Anyways, need ideas for the possible reasons on why it evolve this way and why this species became isolated in the peninsula from their relatives.
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One correction to your question and that is that among lions the females, not the males do most of the hunting. The males tend to patrol the pride lands and keep other threats at bay. (Probably just a typo from reading your post)
To answer you questions though.
There are two primary reasons why you would have a fox with nine tails.
1. Sexual selection. It could be that mates are chosen based on the size and luster of said tails.
2. Defense mechanism. Many animals use hair and patterns to appear larger than they really are, this can make a predator see them as more of a threat than they really are.
Examples:
1. Among birds in particular plumage is a primary sources of mate selection. Peacocks, Flamingos, and [many others](https://en.wikipedia.org/wiki/Bird-of-paradise).
For a good look at the mating dances [check this out.](https://www.youtube.com/watch?v=W7QZnwKqopo)
If this is the reasoning you choose a couple things to keep in mind. Many of these birds also develop intricate dances for courting and some collect and create a nest...or stage so to speak. Including these facets could make for a really interesting creature.
How would it evolve: Well...that's tougher. A single tail has obvious advantages for mobility and balance...more would be less useful and overly biologically complicated. Random mutation and selection is the only plausible if not overly realistic scenario.
2. Both modern felines and canines have hair on their necks and backs that stand up to make them appear larger. Not to mention porcupines with their specialized hairs. Some skunks also stand up on their front paws to appear larger (and aim their stink...). I should also mention the blowfish...The same could be done with tails.
How would it evolve: Well similarly its probably going to have to be random mutation. If you combine these two ideas it is plausibly enough to make the random mutation (or more likely a series of random mutations) stick and be selected for.
As an added unrequested idea you could make the tails have a pattern and move in such a ways as to sort of pacify both predators and prey.
Oh and one additional note. It is not crazy that the male and female look different. That actually happens in a bunch of different species (though no mammals that I can think of off the top of my head).
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Birds provide many examples of sexual display and your description reminds me of peacocks, displaying their tails to win the hearts of girls (peahens?). One difference is that birds do not form hunting packs, but are alone, or form pair bonds.
So I'd suggest that your pack be made up of pair bonded couples where each couple has courted with displays of big tails.
Consider too, why is a nine tail display evolutionarily superior? Does it give nine times the magic power? Do you have to be stronger to display nine tails? Is the favorite prey easier to kill while staring at nine tails? Is the worst predator of these animals fooled by nine tails? Or does a big tail provide protection for cubs from terrible winter conditions?
Severe winters may provide a compelling reason for isolation from regular foxes.
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[Sexual dimorphism](https://en.wikipedia.org/wiki/Monogamy_in_animals), especially where males are larger than females, is associated with non-monogamous mating patterns, in which males compete for female sexual partners. Size gives an advantage in this competition, so is passed down to the next generation by the successful males.
Also associated with female sexual choice is displays, such as the peacock's tail. When mating pairs form long-term monogamous bonds, the males and females tend to be similarly sized, and the non-productive types of mating display tend to be smaller and simpler.
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**Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers.
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It always bugs me, if third party candidates have no chance because they have significantly less money for their campaigns or just because they are simply weird:
The date is 1st May of 2016. Everything you know till this moment is exactly as you knew it. But we will change one thing:
It is becoming more and more apparent, that candidates of main political parties will most probably be Donald Trump and Hillary Clinton.
One [super rich billionaire](https://worldbuilding.stackexchange.com/questions/57056/how-much-could-a-time-traveler-earn-by-selling-a-smartphone-from-2016-in-2000) realizes he does not want either of them to be president.
It is bit too late to run for president himself, so he decides to give 2 billion dollars to fund the campaign of a third party candidate.
Because I am personally fan of Green Party, he decides to give all this funds to [Jill Stein](https://en.wikipedia.org/wiki/Jill_Stein)
Yes, I am aware of fact that one person cannot give that huge amount of money himself. But I am also aware of fact that there are way of how to do it (create dummy non-profit organizations, and so on).
So, please keep out of scope the fact that it is really hard to donate that amount of money as single person. Also assume, that Jill Stein is going to accept that money without asking and use all of it for her campaign.
So, say that from middle of May of 2016, Jill Stein is *everywhere* - she has lots of ad space to rent, she has lots of celebrities to endorse her...
Will this be enough to get her elected as president in the modern United States?
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No. There are far too many people who will just always vote for a specific party and always have voted for it.
There are "swing voters" but generally the result of an election (in places where voting is not mandatory) is more about whether a party can mobilize their "core support" than which way the swing voters swing.
Because those core supporters are only really deciding "vote or not" not who to vote for the two main parties have a lock in unless something happens to radically disrupt that voting base.
Note that Trump got where has has by being one among many and having the other votes split between his opponents. If he was standing as an independent presidential candidate he would get no-where.
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>
> Can money buy you position of President of United States of America?
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## Of course
It would be probably too late with *this* election, so I'll speak about case when there's more time to prepare. With infinite money it is definitely possible, without money - not so, hence money can definitely byu it. The trick will be to figure out reliable way to do it that is also cheap enough to bother.
First of all, citizens do not elect the president, electoral college does. Bribing ~300 of ~500 actual voters is way easier than bribing significant part of the population. This is what brings victory. Sure, these people usually reflect how people in their state had voted, but they are under no obligation to do so and sometimes they *do* vote differently.
Their votes are public so simply bribing people responsible for counting would not fly.
However, making a lot of actual voters to vote for some unpopular candidate would be expensive. Thus, you'll have to make your candidate popular enough.
Uprooting two-party system would be expensive. Sure, if there's a third-party who's quite similar to a candidate of mainstream party and that causes something like 25-35-40 citizen voice split (mainstream-3rd party-mainstream), strategic voting for 3rd party candidate by actual voters may look feasible with explanation like "It's obvious that people want either of those, so we made sure they get either of those". That's an option.
However, there's another option to *use* two-party system and make sure that your candidate is one of mainstream ones. This nets you lots of voters and makes electing your candidate believable. If either of candidates is controversial enough, nobody can have good estimates on how citizens will vote. This will allow you to get creative with counting citizen votes and ensure good results for your candidate.
## Fool's gold
Having control over POTUS is nice but why would you need all that power? Usually if you have lots of money you already work fine with existing system. Major changes are more likely to disrupt your money flow. If you need some legislation or whatnot it would be orders of magnitude cheaper to buy it and don't bother with control over President.
It would *maybe* make sense if lots of players pooled their money to promote their common corporate shill, but other than that you're better off with buying small favours from big people or their underlings rather than creating big people for exclusive use.
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## yes, wait, maybe?
Let's state a few political truths
1. People vote, likely for candidates they agree with.
2. You need money to run a campaign.
3. There is a maximum campaign coverage.
4. There winds up being only two *real* choices by the end
Because of the fact that people vote, mixed with truth 4, means that just because you guaranteed she makes it there, does not mean people will vote for her. She needs to win over the people. Because of truth 3, there is a maximum that money can buy and that leads to your answer;
To guarantee presidency, you need to buy it and because of how presidency works, you need to buy votes in order to do that. That is illegal, so the answer is no, but then again, depending on your wealth, you could;
* Go back and offer a 0% tax, pay for the nation out of your pocket, this will likely end in bankruptcy and a terrible fate for the nation.
* Suppress the courts, buy the judges, pay off the jury, etc.
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### Campaign finance
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> Yes, I am aware of fact that one person cannot give that huge amount of money himself. But I am also aware of fact that there are way of how to do it (create dummy non-profit organizations, and so on).
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Non-profit organizations cannot give candidate campaigns money. They can only fund things like advertising that cannot be coordinated with the candidate campaigns. But of course rich people can do that directly. All the non-profit gives is pooling (more than one person contributing), which you don't have here; and anonymity, which you don't mention as a goal.
The easiest way for a rich person to magnify donations is to give to each and every campaign committee in all fifty states plus the national committee. They have much higher donation limits, and there are a lot of them. This works bests for major party candidates though, as the third parties don't necessarily have matching organizations.
Another trick is to have a business that gives out discretionary bonuses each year. Let it be known to your employees that you favor Jill Stein. Then increase their discretionary bonuses by the amount of any contributions that they or their spouses make. So long as you don't announce that you are doing this such that people can testify about it, this is difficult to prosecute.
But let's ignore the difficulty. Maybe you marry Stein. Then your money is her money via community property. So she can spend it all.
### Limited effectiveness
Hillary Clinton is outspending all the other candidates put together by a lot. It's ridiculous how little money Donald Trump is spending. Yet Trump is not losing by a landslide. In fact, he's winning as many states as Romney even though he's not nearly as competitive in spending. This gives a sort of upper limit to the benefits of spending.
Stein also has the problem that her ideology is most attractive to a minority of US voters. Basically left-leaning independents. Unless she would moderate her stances, she would have a great deal of difficulty beating Clinton among center-left voters. Stein also has no state or federal government experience. And no executive experience of any kind.
With enough resources, Stein might be able to increase her share of the vote from 3% to, say, 20% or 30%. However, this would almost entirely come from Hillary Clinton's share. The likely result would be better relative results for Trump. If Clinton and Stein each have 30% of the vote, Trump could win with 40%.
Another possibility would be an electoral college split. If no candidate gets 270 electoral votes (a majority of 538), the vote goes to the House. Republicans do and almost certainly will have majorities in a majority of the state delegations (the vote for President is state by state with each state getting one vote). Stein has no appeal to Never Trump Republicans, so she has no chance of forming a coalition that will win in the House.
### Gary Johnson
Johnson is a more likely candidate. Johnson is a former two-term governor, so he has actual executive experience in government. If the election goes to the House, Johnson does have appeal to Never Trump Republicans. Also if Democrats are left with a decision between Trump and Johnson, their demonization of Trump would make it difficult for them to vote in a way that resulted in President Trump. This gives Johnson a narrow path to victory.
### Infrastructure
A lot of the problem is less about spending and more about infrastructure. Democrats and Republicans have an infrastructure of volunteers who can help with get-out-the-vote operations. Money is only a partial substitute for this.
Democrats and Republicans also have institutional inertia. There are people who've voted for whichever party for fifty years. Even if another candidate better represents their beliefs, they may not notice.
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So I understand how gas giants and their many, many moons operate, and I can make educated guesses about how Earth-sized satellites could orbit a large gas giant, as well as how gas giants can be in the habitable zone. What I'm curious about is developing a civilization.
Suppose an intelligent species *(let's say humans, to make things simple)* originates on the moon of a gas giant planet. The moon has slightly more land than sea *(about 40/60, compared to Earth's 70/30)*, and has an orbit which keeps it within the habitable zone, albeit with some pretty extreme seasons.
Some of the key aspects I'm trying to figure out are time-keeping (calendars) and cosmology. Could a civilization recognize that their world goes around another world which goes around the sun? How would the night sky behave in general; could it lead to cosmology or astronomy discoveries similar to ours?
If I can understand how our calendars arose, it may give insight as to what to expect on a system with a more complicated sky.
I'm willing to provide more details on the world I'm developing, if it helps. Just let me know. Any ideas you all' ready willing to provide are appreciated.
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**Way of Life**
A civilization's way of life is dependent mainly on the area surrounding them. The face of the moon would also affect their way of life. Does the surface have many continents? Or is it mainly archipelago? How does the continents looks like? Vast plains? Or mountainous? What is the surfaces temperature? Does it have many tundra? Or desert? See, many factor would affect a civilization's way of life.
Based on our Earth, mountainous region would have many farms due to its fertile lands. Archipelago would depend on the sea as their main source of food. Vast plains means it is susceptible to typhoon and tornado, like America. Since the moon has more land than water, then it would have more desert since the rainfall should be lower than Earth.
**Time and Cosmology**
The gas giant is the most visible thing they can see on the sky. If they are tidal locking (the moon and the gas giant) then your people would be aware that the land they are on are rotating.
One of the key aspect that caused people in the olden times believe that the Earth was the center and that the sun and other sky objects revolves around the Earth was because they all seems smaller than the Earth. Due to the size of the gas giant, your people would be aware that they are revolves around it. They would believe that the center of the universe is the gas giant, that all things revolves around it.
Thus a year would be the time needed for the moon to finish revolving around the gas giant. Day would be the time where there is sunlight, night would be where there is no sunlight. Also, depending on the composition of the gas in the gas giant, it might be very bright at night due to the gas giant reflecting the sun's light.
**Religion**
Since the moon orbit a gas giant and thus would sometimes have no access to direct sunlight due to the gas giant blocking it, they might develop belief on dark deity that caused the world to be engulfed in darkness for some days/months/years, depending on its revolution angle relative to the gas giant. Since the gas giant is also the biggest thing on the sky, they would also worship it.
As science progress, they would develop more awareness of their home world. Some of the scientist might get persecuted for their discovery.
You might also want to read [this](https://worldbuilding.stackexchange.com/questions/49349/earth-as-moon-of-jupiter?rq=1).
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Assumptions - atmospheric pressure is 3 atm, but partial pressure of oxygen is comparable to earth, the rest is mostly nitrogen. Planet is tidally locked and insignificantly heavier. (for simplicity reasons, I assume that humans are able to adjust to that pressure, it is generally below the amount that causes nitrogen narcosis)
OK, so what would be consequences for any story happening in such setting?
1) changes in the air transport, airships would become much more practical than on Earth, piston aircrafts would need much shorter runaway (low quality airstrips would become much more acceptable), but anything fast (jets) would have troubles in getting enough oxygen without getting clearly too much friction.
2) Vehicles would really have to be aerodynamic and better slow because of heavy drag (unless there is some good reason to burn fuel more generously). Do I get correctly that a car designed for Earth would for the same speed use 3 times more fuel, while the same fuel efficiency would get while driving $\frac{Earth speed}{\sqrt{3}}$
3) If anyone uses bike on such planet, it would be a recumbent bike.
4) Maximum range of guns - divide by 3 (?) effective presumably not so much reduced because that part of effective gun range is defined by aiming problems, which would not be affected.
5) Reduced effective range of any grenade, bomb etc in to 1/3 of that on Earth (?)
6) More native, airborne creatures. Earth chicken would turn in to a formidable flier. ;) (any design including insect-like, flying fish-like)
7) Milder climate than otherwise because of heat retention and better distribution.
8) Winds with greater force (so boost for any sail ships or wind turbines). But shouldn't the speed actually go down?
9) Water boils in something like 126C degrees.
10) Higher boiling point means less evaporation, less evaporation means less rainfall (how to get any real numbers?)
11) Harder to set fire to anything, as huge quantity of denser air would take this heat away
12) Breathing in cold air would be much more harder, as there would more heat lost with each breath
Anything to correct/add? Any idea how instead of "more"/"less" get some science based numbers?
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Oxygen toxicity could be a problem. This isn't a straightforward issue. It depends on the length of exposure and the organs of the body affected. For some preliminary research, try the Wikipedia entry on [oxygen toxicity](https://en.wikipedia.org/wiki/Oxygen_toxicity) and [*Oxygen Toxicity*: a brief history of oxygen in diving](http://archive.rubicon-foundation.org/xmlui/handle/123456789/6014).
A number of the research studies involved pure oxygen at short duration. There is the possibility of harm at prolonged exposure, for example, people living and working in a dense atmosphere.
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> There is no clear understanding on the exact biochemical processes involved with CNS oxygen toxicity, nor is there a clear consensus on what the "safe" upper PO2 limit should be. Convulsions have occurred in divers breathing an inspired PO2 as low as 1.2 ATA, but such cases usually involve extenuating circumstances (such as medical conditions in the divers which pre-dispose them to convulsions).
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The above quote comes from [Diving Physics and "Fizzology"](http://www.bishopmuseum.org/research/treks/palautz97/phys.html) which discusses partial pressure adverse effects for various breathing gases including oxygen.
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> When immersed underwater, most divers regard a PO2 of 1.4 ATA as a safe upper limit during periods of physical exertion, and 1.6 ATA during periods of rest.
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Where 1 ATA equals surface atmospheric pressure.
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For number eight, an increased density atmosphere would decrease the thermal contrast between the poles of a tidally locked planet. This in turn would mean less forcing and lower wind speed. This would be a bit of a bummer for wind-carts, but on the bright side, the habitable belt of your planet would extend further out on either side!
If you wanted to lower the thermal contrasts even more you could have the planet rotating slowly on a synchronous orbit with the sun or primary. If a tidally locked planet rotates fast it has a strong Coriolis effect which means the creation of an equatorial jet. This jet lowers the heat redistribution efficiency of the atmosphere, meaning higher thermal contrasts among the hemispheres. A planet that rotates more slowly has a negligible Coriolis effect and thus no equatorial jet. The air circulation would be a simpler anti-stellar to stellar flow.
Just wondering, what is your planet tidally locked to? Is it a sun or another planet? If by any chance it is tidally locked to a red dwarf, just remember that even old red dwarves flare occasionally and creatures that spend more time in the air are more vulnerable to solar flares.
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The planet's tidal locking means that the day side would be too hot, and the night side would be too cold, forcing humans to live within the twilight strip. However, the atmosphere's density will help decrease the temperature range, expanding the habitable zone out. Megafauna will be more capable of surviving, due to oxygen more easily absorbing into lungs, and thus, the organisms will be a good amount larger than their Earthly counterparts. If they were to survive unaided, humans would need to live at higher altitudes, and due to the atmosphere being approximately 6.7% oxygen, 92.3% nitrogen, and 1% other, we can assume that its molar mass is 28.41 g/mol. The scale height would be about 7.5 km, assuming a mean temperature of 250 K, and we could use that to find where human life would be possible.
At that altitude, atmospheric pressure would drop to 1.10 atm, and that's not enough oxygen for human survival. Humans would need special equipment to be able to safely explore the surface, at least until evolution adapts their bodies to the increased pressure.
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Suppose the worldbuilding itself is an artistic creative effort, rather than just a means to write a good novel. People have asked about [software for organizing information](https://worldbuilding.stackexchange.com/questions/499/what-software-is-available-for-keeping-and-organising-notes-about-your-world) before. But I'm raising the question where the method in question is the publication mechanism as well.
There are indeed wiki sites for various popular franchises including Star Trek and Harry Potter. I'm thinking what I want would be classified as a "wiki", but with specific features.
It starts off with the author making the content. Others would not edit that, but I want people to be able to attach comments to specific points, not just to the bottom of the page as a whole. Think about reviewing tools in documents.
Eventually, when it (or some area) is finished, it can be released under a *creative commons* type licence and open those pages to editing by anyone. I expect it to have version history.
It should allow for formatting the content with bold and italic etc. but not limited to only that: a created style might need a custom font or color for example.
Any wiki allows for embedding pictures in some way, but what about navigating map content with pan and zoom? How do you post and edit such maps? Vector content in general, so CAD drawings can be exported to a vector format for posting, not huge or low-res bitmaps.
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# [Fractal Federation](http://www.fractalfederation.com/)
While this website might not offer all of your mentioned features, it is at least a website that is designed to create worlds. It offers mainly Wiki-style pages that are categorized by universes, but can also be tagged with metadata.
Maybe ask the site maintainer whether they want to include any mechanism for display of maps and models?
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**World Pages**
Each world could have its own wiki-like page, which would be under control of the world author. This page would have a display view and an edits/history view. In the display view, there would be no comments or history shown, while the edits view could contain suggested edits/comments to the page.
There would be no automatic inclusion mechanism for edits. Instead, the author of the world would be responsible for choosing whether or not to incorporate these edits. This would give the author the final word over their own world. Alternately, for a collaborative project, a main author could choose to give editing privileges to other worldbuilders, after which they could include edits into the page or make their own additions to the content.
Not all worlds would be in a 'published' state, however. In order to maintain a high level of quality in terms of world visible to the general public, a curation process would exist in which members would vote on whether a proposed world was sufficiently detailed to warrant its publishing. A 'no' vote could be required to have an explanation as to what would need to be added to a world for its publication. In order to facilitate the publication of worlds from more prolific authors, a reputation system, similar to what exists on stack exchange, could be implemented, for which a user with sufficiently high reputation could more easily publish worlds, either of their own design or submitted by someone else.
**Mapping**
For web-based mapping, it would probably be best if the site included not only a way to import worlds created externally, but also to author new maps. A basic svg-based map making system could be used for authoring, the final version of which would be converted to SVG. The map making system could include layering and alternate views. This would allow an author, for instance, to create both physical and political maps of their world, and would allow a user the ability to toggle features like roads and environments on and off.
Further extending the mapping functionality, a mapping toolbox of web applications assisting in generating worlds (such as a fractal-based map generator) could be incorporated. These tools would allow a user to more easily generate maps for their worlds.
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This is a **calendar** question, for the Fortnightly Topic.
# Background
On planet Polarworld, a future alternate Earth, the ambient temperatures are so intense that the only habitable areas are at the poles.
Now for reasons that almost certainly aren’t relevant to this question, this situation was not always thus. In other words, Once Upon A Time in the Time Of Legends, the poles were frigid, inhospitable wastes, and people lived in the areas in between. Over the many millennia since The Time Of Legends, people have migrated to the two poles.
Technologically, these two civilizations are about as far forward as early modern Europe, say somewhere from 1450-1700—except that their abilities in navigation are minimal, because the oceans are so horrible that there isn’t a lot of deep-sea exploration undertaken. One interesting result is that these two civilizations have effectively no knowledge of each others’ existence. So far as each knows, their people were the only ones to survive by migrating far to the pole.
Well, eventually these folks independently discover the principles of radio (not at precisely the same time, of course), and soon enough discover each other. Once basic language problems and such are resolved, they start trying to share knowledge about their mutual history—and discover a major problem in the form of the calendars.
# Calendar Problems
Northpole society and Southpole society have quite distinct calendars, naturally. The real problem, once they start talking to one another, is that these calendars don’t readily align with one another. Some factors in this:
1. Each society has its own night sky.
2. Seasons are exactly reversed.
3. There are long periods (the high summers) when celestial observations are very difficult because the sun is always up.
You will of course recognize many others.
# The Systems
**The Southpole calendar** centers around precise observation of glacial calving. As the seasons drift toward summer, a bit after the vernal equinox, a few major glaciers will calve. This is watched and measured with intense care and precision. When the experts judge the time to be correct (when a certain exact amount of calving has been completed), then at that precise instant the Calvendar [har har] is held to have begun for the year. The Calvendar ends at midnight on the vernal equinox. Between the equinox and the calving is an intercalary time during which everyone hides in their cities and parties hard to drive off the spirits of darkness.
**The Northpole calendar** does everything on the basis of celestial observations, with a strong preference for observations of Venus (since she can often be seen even when the sun is up). They have become extremely precise about their celestial observations, and can predict the arrival of long-range recurrent phenomena (Halley’s comet, for instance) with enormous accuracy. They consider that the year always begins at the moment of summer solstice, which they calculate and observe very precisely. But they also know that the Earth year is 365.24 days (8765 hours), and they hold that earthly observations are inevitably false. Therefore, their calendar doesn’t put day and night in the same place all the time. They divide everything into 5 Great Months of 1753 hours each. For convenience’s sake, these are cut into 56 Days of 31 hours each. Between the first and the second Little Months of 28 Days each comes a Starday of 17 hours, during which great festivals are held in honor of the various Star Spirits (this is especially exciting when Venus can be seen during a Starday). Of course, it is true that one cannot look at one’s watch, see that it’s “noon,” and on this basis assume anything whatever about whether the sun is up or not, but that’s sort of true anyway if you’re living at the pole.
# The Question
How might the Northpole and Southpole calendars be reconciled to one another with minimal transformation?
Note: A mere *translation* is a matter of doing the math and spending a lot of time with the Southpolers’ calving charts. But now that they’ve realized that they’re All One Human Society Together and so forth, they’d like to have a single calendrical system that respects both traditions. So how could that work?
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One way to solve this would be to look at the way we have reconciled calendars in the Western Europe. We have on one hand the Gregorian calendar and on the other the catholic feasts calendar. The difference is especially visible for the date of Easter which is a date calculated and not based on astronomical observations.
Similarly they could have the astronomical calendar the one being used for daily activities and work and keep the `calvendar` one to determine the dates of celebrations.
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That's an interesting question.
I think the best way to combine them would be to recognize that the astronomical one is more stable in that years are always the same length and it is more regular in use.
However to respect the traditions of the Calvendar the dates and holidays from that calendar are incorporated into the first one.
In other words the actual telling of time is done using the astronomical calendar, however the timing of holidays, feasts, etc. The "new years party" is done based on the Calvendar.
This lets both cultures feel like they have had input into the combined calendar.
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I have a scenario that I have, and I *feel* like I have it fairly well developed, but I can't shake the feeling that there's *something* more to it than I expect. So here's the scenario:
The Draconi are a race, effectively, of dragons in human form. Think lizard-men, but able to breathe fire. They exist in a medieval, D&D, World of Warcraft, Lord of the Rings kind of world. They are the kind of nobility who enact the typical "luxurious royal life contrasted to miserable peasant life" in their kingdom. Recently, the Draconi King and Queen have gone off on a continental voyage, leaving their son, the Prince, to rule.
However, in their absence, the Prince has taken an iron fist to the kingdom; never truly taught to learn restraint, he now takes a slightly bratty, "take what I want because I can" attitude, very similar to the real-world Roman emperor Caligula. He spread his rule outward into neighboring, unruled villages and towns, and violently conquested them.
He's become legendary and infamous. There's rumors he kidnaps women for his own pleasure, and they might not be untrue. However, a few factors prevent other kingdoms from going into war with him: Number one, the Draconi Kingdom is one of the most powerful kingdoms, ever. They have an enormous military, and on top of that, they have tamed dragons - there have already been discussions about the overwhelming power of dragons as a military device. Number two, the Kingdom is powerful economically as well; it is set on top of a very mineral-rich region, and has a high number of valuable exports. And three, it is currently surrounded by a large ring of uncolonized wilderness, which takes about a month to cross. The Prince has refrained from waging war on any other kingdoms for strategic reasons.
I've already considered assassinations, attempts to overthrow, rebellion, the considerations of war and the like. But I still can't shake the feeling that there's something that's slipping my thoughts. So my question is: Does the political status of this kingdom seem realistic? Are there factors I've failed to consider?
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As others have mentioned, there are wheels within wheels to this problem. Luckily you, as the author, can simply assert things happen a specific way - regardless of likelihood.
## A little background
Typically Feudal governments balanced power between the monarchs and the nobility. Various members of the nobility pledge to support the monarch when summoned. The Monarch only directly manages the forces associated with his own land holdings. All the other forces in the kingdom belong to the nobility.
If you are a fan of the book & TV series, Game of Thrones, you can see how messy this sort of arrangement can get when some of the nobility figures it can do better on its own or has a chance to replace the Monarch.
Similarly these sorts of kingdoms tended to grow to the limit of their ability to manage, rule, control, and protect. Which means your relatively powerful Draconia will be surrounded by lesser powers who in aggregate are more powerful than Draconia.
Meaning to survive politics (both internal and external), the monarch need to be clever or have clever people working for them constantly balancing these various threats to the throne. Frequently, the monarch will set various threats against each other to keep them from eyeing the throne.
## The Prince
Leaving a bratty and presumably annoying prince in power means that prince will begin to draw the ire of both the kingdoms own nobility and also the ire of surrounding countries.
In fact, the prince might do unnecessary taunting, make unreasonable demands, issue bad proclamations simply because he thinks he can.
Over time this will tend to make the nobility switch from internal squabbling and focus most of their attention on the source of their biggest irritations. The same will happen with the surrounding countries.
Some of the clever & powerful nobility might begin to think the kingdom would do better under their leadership and make plans accordingly. The most clever of the nobility will begin seeking alliances with others both inside and outside of the kingdom. Some as true allies, some as temporary allies, and some as patsies or fall guys if/when the king & queen return or things turn out poorly.
With a composite force of both Draconian nobility and outside countries, the outside country wouldn't have to worry as much about the Draconian qualitative advantage.
Basically if the prince becomes annoying enough, he'll focus everyone's wrath upon him and his kingdom and eventually be overthrown.
## The problem
The longer the pre-prince political situation was relatively stable, the longer it'll like take for the prince's opponents to mobilize and coordinate themselves. For example, if the current king & queen have kept the kingdom in a relatively stable state of peace for the last 20 years, the prince's opponents might take years to be able to get everything moving.
If things haven't been stable for very long, then the prince's opponents might be able to organize a strike much faster. But to my thinking, it makes much less sense for the king & queen to leave the kingdom under these circumstances.
Perhaps a more likely scenario would be if the prince had already reached maturity and had a hand in the rule of the country. If he had, he would already have developed enemies. Those enemies may have already plotted the overthrow of the prince after the king dies or abdicates. In a situation like this, the prince's enemies would have to vastly accelerate their plans to dethrone the prince before the king & queen return.
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One giant question comes to mind. **Why is there a month's worth of distance between this kingdom of kingdoms and everyone else?**
If this kingdom is truly the most powerful and most wealthy, it stands to reason that the surrounding regions would be populated. This is particularly true if they protect their kingdom well (patrols on roads and in villages).
I say this because you imply that A. The leadership of the kingdom has been good (if not entirely benevolent) and B. They are economically and militarily strong.
People are going to want to trade with them, and trade is a whole lot easier if you are not camping out in the wilderness for a month. If enough traders are travelling to this kingdom to make it economically powerful then inns, small towns and such would naturally pop up along the most common trade routes.
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The fact this kingdom lives in a bubble of wilderness, as has been mentioned, seems at odds with it being wealthy. Wealth is generated through trade. You can have a monopoly on the world's gold mines, but unless you can sell it to someone else it's not going to do very well. Now, according to [Google Maps](https://www.google.co.uk/maps/dir/Moscow,+Russia/Paris,+France/@52.2935202,11.0297687,5z/data=!3m1!4b1!4m14!4m13!1m5!1m1!1s0x46b54afc73d4b0c9:0x3d44d6cc5757cf4c!2m2!1d37.6173!2d55.755826!1m5!1m1!1s0x47e66e1f06e2b70f:0x40b82c3688c9460!2m2!1d2.3522219!2d48.856614!3e2), a walk from Moscow to Paris will take about 560 hours over about 2800km. Which translates into 23 days of walking, so it's going to be over a month to do it. So you're telling me your kingdom is ~2500km away from everyone in a bubble of nothing?!
As has been stated, seems more likely that in order to become wealthy they will have many smaller neighbours, and be the dominant continental power. The neighbours may be sparsely populated. If you still want them in a bubble of nothing, perhaps one way of getting around it is having the kingdom surrounded by mountains on three sides, and sea on the other. Or sea on three sides and mountains on one... or whatever. That way at least they can make use of their material wealth to create a powerful navy to empower their own trade dominance, multiplying their income.
The political question seems more obvious to me. Yes your prince can be as ruthless as he wants and get away with it. It depends on exactly how you create the culture and politics of your realm. Consider that quite often historically kings were regarded as living Gods. Literally. Egypt's Pharaohs, Russia's Tsars, Japan's Emperors, even North Korea's Kim Dynasty. If your monarchs are actually dragon people and the people are not it'll make the claim all the more real. But monarchy manifests differently between nations. England and Sweden for example are unusual historical examples as their monarchs were not absolute; legally bound by constitution or tradition to defer power to other estates.
There will be at the least a noble estate, and they typically were the most powerful of the estates. In the feudal system kings granted land and title to lesser nobles who helped them; in times of war or otherwise. The nobility were effectively the nation's administrators, and without their support the crown will be in trouble.
But there are other groups who held power, defacto or dejure. The church was extremely powerful in medieval Europe, and could often make or break political dynasties, as well as demanding large portions of land from kings to dedicate to monasteries (which were then as often centres of learning as industry) and the like. Back then people were swimming in religion, and there was no division between religious and state; conceptually or otherwise. Royal power was stabilised by church approval. However, the church may not be that independent. For example, the Orthodox Church in Russia has almost always been subservient to the state. Then there are less powerful estates, like the merchants, or the middle class. Who may be more powerful in your realm. Or maybe they don't exist.
To conclude, it's very possible that your royals are bloodthirsty and ruthless and get away with it, especially if they have historically been absolute in their power. Perhaps they were always absolute and not constitutional monarchs. Perhaps the church is their servant and not their equal. Perhaps the middle class doesn't exist and most people are rural peasants who wouldn't know any better. Perhaps the nobility is happy with the monarchy for any number of reasons, and so is tolerant of abuses of power - up until a point.
[Vlad the Impaler](https://en.wikipedia.org/wiki/Vlad_the_Impaler#Defeat) may be a good case study here. He was ruthless, quite literally bloodthirsty, and instrumental in pushing back the Ottoman army. But he was imprisoned in the end by his own nobles because he had undermined their authority.
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I would say it is regrettably realistic. Things to consider:
* In most medieval states, there was a balance of power between the king, the nobility, and perhaps even the most wealthy commoners. The prince will have to regard the will of the nobles, or there will be a *palace coup* which swaps the figurehead without questioning the system. Your description sounds too centralized for a medieval state.
* Smart kings and nobles will try to exploit the peasants without killing them. They don't tax away the seed corn or the food to get over the winter, they only tax *most* of the surplus.
* Heavily oppressed peasants might try to evade by going into the wilderness/forests. That would make them outlaws, poachers, and tax dodgers, and the king would see it as only right and proper to extend governance and protection to these lawless areas. Compare some of the historical roots of the Robin Hood legend.
* The other evasion was to go to the cities, where things might be run by an oligarchy of guilds rather than the heavy hand of the nobility.
* You mentioned that the prince occupied towns. Was any property in those towns owned by wealthy foreign merchants, or religious orders?
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Are there any other noble houses? I presume the prince will seek a princess/queen in due course.
Could the nobles be conspiring for their "house" to become prominent?
Also, what about the political allies of the parents? I guess they aren't in favour of this new direction for the kingdom. Have they been allowed to form a rebellious faction or were they mercilessly put down to consolidate his power?
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Here on earth, the moon is this big white thing that lights the world and hangs in the sky. Every culture on the Earth has incorporated the moon into some of their legends. Sometimes as a woman, sometimes as a man, sometimes as a major god, sometimes as a lesser god. However, on an forested moon of Earth-like description, circling a blue and green super Earth of 3x the size, the stories would be different for no other reason than because they have no big white ball in the sky.
Clearly the stories they tell their children will be radically different than the ones we tell our children. Specifically, how might their creation myths be different from Earth's with their giant blue-green super Earth as their "moon"?
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Endor is a gas giant, so it's not likely that it would have inhabitants on it, at least not ones anything like us.
However, the question can be addressed by imagining a forest moon where our moon is. Imagine a moon up there with an atmosphere and trees and other living things. From earth, it would probably look like a mini-earth floating up there. It might cause cultures to assume that earth is not the center of the universe (as almost all cultures understandably did in ancient times), but rather one of many worlds. It may also have led to a much faster development of spacefaring, as the development of telescopes would have revealed the existence of fauna on the planet with a high degree of culture and sophistication (i.e., Ewoks, who have built homes among the trees and developed a lot of human characteristics).
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The ultra-moon would be Heaven. At the beginning of time, humanity lived on Ultramoon. A giant name (let's say Wally) cast out humanity when they entered his forbidden garden three times (cast out on third entry).
If a person is a good person (by Wally the giant's standards) they will go to Ultramoon when they die. All dogs go to Ultramoon.
Just imagine if there is an industrial-age civilization on Ultramoon. The city lights at night will enhance the belief in the Ultramoon after life.
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## Background
In my magical version of Earth's history, at around the time that humans became anatomically modern 200,000 years ago, a variant of the human female gender arose with batlike wings around 6m wide when extended and feet that are more like birds' talons, who could fly thanks to the presence of magic. These females came to be referred to as Lilim, in reference to the best-known member of their gender, Lilith. Lilim and women each bred true, producing offspring that are either male or females of their own type. In a relatively short time (10-25 thousand years), despite lilim's birth rate half that of women (more on that later), the winged lilim form superseded the wingless woman form as the body form of all female humans, due in the most part to the lilim-form's greater survivability and ability to protect offspring in the hostile wild environment of the time.
To summarise, Lilim can fly quite well as long as there is background magic for them to draw upon. Individual lilim can also carry aloft loads roughly equivalent to at least their own mass, and each extra lilim co-operating can double that, up to a point that can nevertheless be almost preposterously high - on the order of millions of tons with the right team. Lilim are more like men in their psychology, including desire for social dominance and selection of sexual partners, tending more to select on the basis of appearance than for their ability to provide for offspring long-term as tends to be the case with women. They tend to prefer dominant sexual positions to those that leave them supine with their wings trapped against the ground (which would become a significant point of contention with men on earth)
Lilim differentiate from women at six to eight years of age (though sometimes the change may not begin until the early twenties, well post-puberty) as they grow wings and their feet change into talons over the following three to four years. Before this, it would take complex magic or chromosomal screening to tell if a girl-child of a lilim will become a woman or a lilim.
Lilim differ from women in that instead of having 2 X-chromosomes, they have 1 X and one L (which is larger than the X). XX offspring did not implant into the uterus due to fetal-maternal incompatibilities, and LY is also a lethal combination due to the lack of certain genes found only on the X-chromosome. A very rare individual can be born LXY - they are anatomically male with wings, but are sterile.
Anyway, when humans began to practise agriculture around 25,000 years ago, a disagreement arose between men and lilim. Men were the primary labourers while lilim continued to flitter around frivolously, and dormant genetic imperatives attracting men to women arose.
A male magician named Adam performed a spell that effectively modified the X-chromosome in one of his followers so that lilim could successfully carry XX woman offspring to term, as long as one of the X-chromosomes was the modified version, and as a result, the first of the new women, Eve, was born, eventually becoming Adam's 'wife'. The altered (genetically modern) X-chromosome spread both genetically and magically, and within a few thousand years, became the only extant version of that chromosome.
This means that modern lilim have a birth rate 3/4 that of women, perhaps a little more, and of the offspring who are born, approximately equal numbers will be male, women or lilim. With women continuing to breed true, producing only males and women, the mathematics of the situation was that - social selection aside - lilim were doomed to become extinct or a minority curiosity.
The most famous lilim, Lilith, discovered an airborne phenomenon that allowed flying beings to travel between worlds via air-filled tunnels (with lengths measured in the tens of thousands of kilometres rather than light-years) between stars which have orbiting oxygen-bearing worlds, known as the Gyre. Faced with the demise of her gender, Lilith conceived of an exodus of lilim to other worlds within the gyre where the dominant men of the time could not follow, and she and a large number of followers and a similarly large number of slave or captured men departed into the Gyre with literal mountains of supplies for a number of new worlds where they could forge new lives on the lilim's terms.
On earth, as magic declined after a major magical war, the remaining lilim lost their wings and talons and after a brief stint in legend and history as Amazons, became indistinguishable from women.
**Edit**
Multiple Lilim can lift around 70kg for around an hour, each doubling in mass or duration requiring an additional lilim, each of whom spends the minimal amount of their total magical power. The limiting factor is the magical power of the weakest member and the number of lilim that can touch at elast some part of the object (which may be a parcel of smaller objects).
A single lilim may linearly increase the mass or duration of a personal load by increasing the cost. This limits a typical lilim to 70kg for 15 hours or 70kg x15 =1050kg for 1 hour, at which point they would be magically exhausted, and would need to recover over the next 24 hours to be at full power again.
Should a lilim drop an object, the magical cost must be spent again to pick up another heavy object.
Lilim also have power over the winds for as long as they concentrate, at twice the cost of Lifting their base mass. They can create, still and direct winds up to 100 kph with one lilim, 180 kph with two, 240 kph with 3, 280kph with four, 300 kph with five and 320kph with six or more lilim. If two groups of lilim oppose one-another, each acting/opposing pair cancels each-other out, and only the unopposed lilim count for purposes of the wind their group can control.
## The Question:
Given that Lilim are entirely comfortable with heights and can, when co-operating, raise truly stupendous amounts of material into the air - and with a little magic, can pin a structure in the air relative to another nearby object (such as a point on the ground several kilometres below, or a nearby airborne structure) effectively permanently, allowing airborne towns, how might these lilim live? How would they treat men and women who would naturally be ill-at-ease living in an airborne lilim town? What would be the fate of their female offspring who proved to be women, not lilim?
I'm aware that there could be a lot of answers to this, but I'm looking for answers that leave Lilim as a significant part of human society in their new worlds, either as equals or dominant to the other genders.
Is it inevitable that lilim would need to live as mistresses over the men and sterilised outcast women (those that weren't killed for not being lilim) toiling below their lofty airborne cities in order to remain a viable part of *their* part of the human race, could some semblance of equality exist, or would there be worlds where the lilim have allowed themselves to dwindle and perhaps even vanish rather than become cruel mistresses over the rest of humanity?
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There is no real point to airborne cities unless you have vehicles for transporting cargo in the air. With magic airships might be practical, but they'd probably be too expensive to compete with water transport. So cities and most of the population would be on the ground and along rivers and coasts.
Airborne structures would be defensive or ceremonial in nature. Since such structures would have obvious value over ground based competition and would be accessible only to lilim or people assited by lilim, lilim would reasonably end up as the military and religious caste. This would give the lilim a superior social status compared to the rest of the population. Powerful kshatriya and brahmin families would live in their airborne palaces, guard their airborne keeps and towers, worship in their airborne temples. And men and women would toil below to support their better in form of taxes and tithes. (Protection and spiritual guidance would presumably be provided in return.)
As for reproduction. It would mostly be between men and women to supply the population of lower classes to do the work. The lilim would presumably have some suitable men in their palaces as servants, advisors in managing the administration, and for breeding. I'd presume that lilim would only have sex with men when they actually want children and that being chosen as a father would be a great honor given in return for years of faithful service. Men and women born would presumably be given to the father, while lilim would be raised by the mother.
This would create an administrative caste of men and women with significant lilim blood that would act as an intermediary between lilim and others. There would be little reason for lilim to interact directly with the lower castes outside war or rebellion. And some religious rituals where a choir of singing lilim priestesses blesses the people from above.
Reasonably the relationship between lilim and others would then be defined by this administrative caste. Since they'd be blood related to the lilim they serve, the relationship between lilim and the "mandarins" would probably be fairly good. The big question is the relationship to the lower castes.
The good news is that I do not see anything that would predetermine it. The mandarins could be strictly separate from people without lilim blood and combine the insanity of apartheid with the strict caste society of ancient India. Or they could be like the gentry of the British Empire and have good social mobility and intermarriages with wealthy merchants. Who'd in turn be fairly open downwards as well. As above, so below. In a society like that the "low born" (not born in an airborne building) might have extensive legal rights and great deal of autonomy. There could be family relations or patron-client relation from the top to bottom, so abuses and issues of the low born would **eventually** be addressed.
The question is really too speculative IMHO for a proper answer, but I hope this helps.
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Referring back to <https://worldbuilding.stackexchange.com/questions/2781/magic-came-back-catastrophes>
In the interest of narrowing questions down, I am splitting these out into particular elements and element combinations.
So, in summary, Ley Lines have just become active again on Modern Earth, and are wreaking natural and unnatural havoc on the world.
This question will focus on the Wood ley lines, and their interactions with the world around them, as well as interaction between Wood and the other 2 elements not yet covered: Air and Earth. Ley lines are not restricted to a particular area, but exist across the entire world. Some places have denser concentrations than others. (Interactions with Fire are covered [here](https://worldbuilding.stackexchange.com/questions/2782/magic-came-back-catastrophes-fire-based-disasters) and Water is covered [here](https://worldbuilding.stackexchange.com/questions/2783/magic-came-back-catastrophes-water-based-disasters)).
What are catastrophes that could be caused by very high volumes of Wood magic going rampant, and clashing with other elemental magics also going rampant? Again, this can be of any scope, as long as it does not result in a mass extinction event. And I'm quite okay with every combo not always producing the same results.
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Even if a surge in Wood magic leads to a relatively fast eruption of forest or jungle where before there was no dense vegetation, this could have some disastrous effects for the species and people who had adapted to its previous situation. When a large contiguous area of land changes its biome type, it will tend to be a different kind of habitat loss for whatever lived there before, even as expanding tree cover can deny needed light for underbrush, etc.
For example, if there are large migratory herd animals adapted to a certain path that gets overgrown with forest, the herd may not follow its old path, which might be a huge problem for them, or if not for them, for whatever was used to them appearing where they used to appear. Displaced predators and prey may roam to new areas, disrupting farms and other species, or grazing away plants needed to prevent erosion elsewhere.
Plants also have large effects on landscape erosion and possibly river water, possibly causing diversion of rivers away from cities which depended on them, and leading to flooding elsewhere, or subtler effects such as reduced erosion leading to less minerals in water leading to affected adapted plants downstream, and so possible mysterious crop failures as conditions change.
Bird migrations may also be greatly affected.
Those are all just relatively subtle effects of biome changes. If the Wood magic can cause mutations or even the appearance new or old species somehow, depending on what the nature of this magic is, you might have the appearance of great beasts or "monsters". There might also be great witherings of existing plants, or a great eruption of mold and fungus spores making practically all food impossible to preserve. There might also be high levels of effective toxins, hallucinogens, or magic in all the plants (or even all living matter) in the area, disrupting, changing, or wiping out pre-existing life in the area, as well as creating a lot of potential spell and potion ingredients.
Perhaps there could be a perverse interaction between berserk Wood and Fire ley lines, where fast eruptions of flammable plants were followed by sudden fires, leading to an awful series of large-scale landscape fires. Perhaps an Air ley line might do something awful with all the resulting smoke, as well. There could also be an awful mixture somewhere of crazy swamp life producing lots of methane, directed by Air magic to wash over and choke out air-breathers somewhere, and/or be suddenly ignited by fire, leading to huge methane explosions far away from the magic swamp that generated the methane.
Greatly increased fertility in any species can have awful effects - locusts, mosquitoes, giant wasps... even on Earth there are some terrifying giant wasps - if boosted to great numbers and aggression by magic - yikes! Water creatures might also suddenly be a great danger if hit by life magic - perhaps plagues of piranha, aggressive sharks, giant kraken, or super-fast-growing giant barnacles eating through ship hulls.
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# Effect of rampant wood magic
Since according to your linked question, wood magic is connected to life and growth, I would expect that rampant wood magic would cause things getting alive and/or grow larger than normal.
For example, wood (furniture, roof frameworks) could suddenly come alive again, growing fresh sprouts (and possibly destabilizing any wood construction). Als, dead animals/human corpses could come back to life, but without their mind coming back, making them a sort of zombie (but without the usual behaviour/infection traits of classic zombies).
The growth aspect would make all sorts of plants to grow faster and larger. This will especially be the case for weeds, which may cause problems not only for agriculture (where the weed overwhelms the crop), but also in construction (weeds growing through asphalt and destroying it, or plants growing in wall slits, ultimately destroying the walls with their roots.
Another thing whose growth may be amplified is moulds. Wood structures could be weakened and fail due to that.
# Interaction with other magic
## Earth
Since you wrote earth is for durability, this means that the plants that grow are very durable; for example, there would not be weeds, but trees growing in the walls of houses, and destroying them. Also, it would cause weeds that are extraordinarily resistant to herbicides, and zombies that are especially hard to kill.
## Air
Since you associated air magic with rapid change, it would add to the rapid growth due to wood magic.
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With wood or growth or 'life' things could be very interesting. As it goes wild because it is not where it belongs and is 'searching' it will likely be trying at the same time to force it's location to at least partially meet it needs.
So lumber in buildings and structures might sprout and grow. Urban areas with sparser life might have huge changes. Since there is 'less' to absorb the power. Rats might grow to huge size or propagate at incredible levels overrunning sections of the city. Fungus would go wild, might even 'evolve' to 'eat' steel or glass, making it possible for a sky-scrapper to rot away. As people are going to be one of the largest groups of living organisms they could be affected as well maybe turned into trolls, elves etc... though I am assuming humans are mostly going to be ignored.
Wood would be very much be enhanced with water allowing for huge growth potential for plants, maybe even causing tropical jungles to spring up overnight, even in the middle of a desert.
Wood with Fire would be a volatile mix where fire would try and consume wood.
wood and air, this is a little harder, unless tornadoes gain a 'life of their own'
wood and earth, if they meet in a city, wood could be strengthened enough to do terrible damage to sidewalks, buildings and roads.
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Remember Journey to the Center of the Earth? The premise is that there's some kind of cave in the center of the Earth, which has an ecosystem inside it. Well, of course you can't do such a silly cartoonish thing with a planet like Earth. Firstly, it couldn't form naturally, and you couldn't create it artificially. Long before you would get to the center of the Earth, your drilling equipment would melt, and your tunnels would collapse.
But what about other smaller worlds? The concept of hollowing out asteroids to make a habitat is already a thing. How far can you take this? What is the largest object that can theoretically support a cave or void in the center? My basic assumption would be that dwarf-planets are a reasonable cut-off point, since they are compressed into spherical objects by their own gravity. This should squash any voids out of the center, and these can no longer be supported by using the material of the asteroid. Then again, dwarf-planets probably take some time to do this, and it's possible that you could create a void that would slowly slump under self-gravity, giving you time to reinforce it by bringing in stronger materials than the natural rock.
I checked up on what the pressure at the core of Ceres is calculated to be, [and based off this paper](https://www.researchgate.net/figure/Pressure-in-the-center-part-of-Ceres-The-pressure-is-calculated-with-Eq-A2-in_fig2_258295603), it seems to be between 140-200MPa. The paper suggests that Ceres is quite porous. [Still the compressive strength of concrete might be 70MPa at the very most](https://www.bigdreadymix.com/what-is-the-standard-strength-of-concrete/), so as I would have thought, digging into Ceres' core to create a cave would not work. I'm not sure how to calculate the core pressure of an object, but if it varies linearly then perhaps an object half the mass of Ceres is about on the limit where you could create a small void in its very center.
I'm not sure about temperature. [Buried within this paper](https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2004JE002244), I find that the core temperature of Ceres is thought to be ~350K/76 degrees Celsius, a bit too hot but not immensely so. Half that temperature is a very hot summer day but manageable with cooling systems, but I don't think temperature varies linearly in this way, so an object with half the mass and similar other parameters might not be expected to be twice as cool inside. Given we are dealing with volume, there's probably a cube root in whatever formula would apply.
My guess based on my own limited research is that creating and holding up a void within a body like Vesta might be possible, as it is 27% the mass of Ceres, and probably substantially cooler in its core. It isn't even spherical, but is still a fairly massive object as objects go (equatorial escape velocity is 360m/s). Any actual calculations are welcome.
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It's not easy to calculate the core pressure because heavy elements tend to sink to the core, the density we can estimate is just an average. It will happen even in objects smaller than Ceres, and here is the big problem, the outer layers are rubble piles, pieces of rock held together more by the gravity at the centre than by sticking to the neighbouring rocks. Beyond taking into account the risk of a collapse you have also to take into account the risk of big chunks of rock falling off and eventually the whole thing falling apart. It is not worth the pain, and entirely artificial object would require only a small amount of extra work and would be a lot more stable.
You could try to dig a big cave in the outer layer that does not touch the core, but even in this case you risk to have pieces falling inside because they did not stick to the other rocks and pieces falling off at the lightest touch like the gas jet from a piece of ice sublimating after being heated by Sun ray, or like a vibration from an asteroid impact on the other side.
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The following creatures, in order, are a sandgroper, a mole cricket and a mole, all creatures that are well adapted for life underground:
[](https://i.stack.imgur.com/rLkCB.jpg)
[](https://i.stack.imgur.com/tqBOr.jpg)
[](https://i.stack.imgur.com/8Obn2.jpg)
All of them converged into a similar bodyplan, with powerful, broad and shovel-like forelimbs for shoving dirt, and with claws or claw-like structures for better penetration into rock and dirt.
And here is the giant ground sloth, thought to have carved out tunnels into solid rock in South America, something nearly unheard of outside of creatures just melting rock to make their tunnels:
[](https://i.stack.imgur.com/XzsLS.jpg)
The reason I'm showing these is because I was designing an arthropod-like creature which I intended to spend most of its time digging below the earth, feeding on plants and other creatures it ambushes by springing from below. The creature is meant to be pseudo-realistic, in that while it's muscles and claws are stronger and more durable than what would be expected for a normal animal, they're meant to be otherwise ordinary creatures following the natural laws.
As for my problem: I'd like for them to be at least as large as grizzly bears, and for them to be ideally able to dig through loose soil at speeds close to 20 kilometers per hour, while also being able to make tunnels through Rock at speeds at least greater than a couple meters per generation (like the sloths likely did).
The problem with this is that I'm not sure what they body should look like in order to accommodate something even remotely close to this type of movement without straight up hadwaving all away. By basic principles, it must have short, powerful forelimbs and a rounded body shape,but as for its forelimbs I'm at a loss. Searching into machines for inspiration was also mostly fruitless, as drills rely on mechanisms troublesome for an animal to have, and the current most used piece of technology for tunneling is similar in its nigh impossible design to adapt to a fleshy creature.
[](https://i.stack.imgur.com/xNRKK.jpg)
The only seemingly good example in a machine that I can see as translatable would be the bucketwheel excavator, a behemoth that can scoop out earth almost constantly because of its bucket wheel, causing there to be constant clawing at the rock and soil. Based on this, the first solution I considered was something with 8 limbs and a bodyplan and proportions similar to those of a mole cricket's, but with 4 digging forelimbs instead of 2, in an attempt to mimic a bucketwheel excavator's ability to dig relatively fast by adding in more limbs into the work. I'm however struggling to understand whether such a bodyplan could actually allow it to dig better or faster, especially since no animals as big as a bear are live digging under the earth, and those that do, even creatures that had more than 4 limbs, seemed to only dedicate one paid for digging, looking roughly like the following sketch to better clarify what I mean.
[](https://i.stack.imgur.com/DAnju.jpg)
With that said and after this apologetically large amount of images, **would such a creature actually reap meaningful benefits from an extra pair of burrowing limbs to move faster through dirt and rock?** As of now, I can't quite tell if simply adding extra limbs could benefit its digging speed, or whether it would even be worth it, as I lack good natural examples.
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**No digging limbs. Only teeth.**
[](https://i.stack.imgur.com/lxdLH.jpg)
Your bear-sized creature is a scaled up gopher. It digs almost exclusively with its teeth. Like the gopher these protrude from the mouth and grow very fast as they are worn down. If your creature is seen face on, all that is evident is the teeth.
Short, strong limbs as well as wombatoid body inflation are used to anchor the creature in tunnel walls and push forward as it digs as well as push soil back. Limbs are also used to push the body forward in an antlion like lunging attack from the tunnel mouth. In this respect also if your creature is seen face on, all that is evident is the teeth.
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I'm designing planets of varying atmospheric pressures. How would increasing (or decreasing) global atmospheric pressure affect the amount/frequency of precipitation over a planet?
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On Earth, low atmospheric pressure is tied to rain and storms. Lighter air is moving upward vertically, carrying moisture to higher altitudes where it can condense into clouds and rain. High pressure is linked to calmer weather. Increasing air pressure means that it will take more energy to move the greater mass of air. A thicker atmosphere can hold more moisture. Twice as much air can hold twice as much water vapor. The overall relative humidity is the same, but the volume of air is increased, which increases the amount of total humidity which can condense and fall as rain.
So, if higher pressure tends to mean calmer weather, increasing atmospheric pressure would create a planet with more stable weather patterns. However, when it does rain, snow, or storm, the amount of precipitation will be increased. This will also cause larger, albeit less frequent, thunderstorms. Some of this also depends upon factors such as planetary rotation and the intensity of sunlight. Faster rotation means higher wind speeds. More intense sunlight means more evaporation and stormier weather. Thus, a planet with more atmospheric pressure, but a slower rotation and less intense sunlight, would have fairly calm weather. Fast rotation with intense sunlight will make extreme weather events fairly common.
Another aspect of increased atmospheric density is that wind will have more force behind it. There is more air mass pushing against objects. Trees and plants would need to adapt to resist being uprooted by increased air pressure. In the movie, The Martian, you see the astronauts fighting against the high-speed Martian winds. In reality, there is so little atmosphere on Mars that even at such high speeds there is barely any effect. That lack of atmosphere is what allows the winds to get up to such high speeds. There is a lack of atmospheric resistance.
I mainly focused on explaining the effects of increased pressure, but you can apply the opposite effects on planets with decreased pressure. Planetary rotation and solar intensity effects would be the same, however.
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The atmospheric pressure does not significantly affect relative humidity, see [here](https://www.thoughtco.com/does-atmospheric-pressure-affect-humidity-3976028), therefore the dew point is also not affected (also see [PST humidity calculator](https://www.processsensing.com/en-us/humidity-calculator/)).
BUT: the light absorption of gases increases with the pressure (e.g. greenhouse gases, like CO2, CH4, etc. but also water vapor absorbs), thus the air temperature increases. This way the water evaporates faster, which might increase relative humidity and this way also precipitation. (Note: it's probably not this simple, because air temperature also increases, making cloud formation harder?/less likely?/on a higher altitude?).
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Higher atmospheric pressure is going to increase the amount of precipitation a planet would experience. Liquids would have less opportunity to gather in whatever cloud formations the planet gets. Lower air pressure would reduce the amount of precipitation the planet would get by increasing the opportunity for liquids to condense in clouds and just hang about in the air.
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One of the problems with [scaling up creatures](https://worldbuilding.stackexchange.com/questions/109716/how-can-we-scale-up-living-creatures-to-be-giant-sized) without increasing their proportions is that their muscles won't be strong enough to support their weight due to [the square-cube law](https://en.wikipedia.org/wiki/Square%E2%80%93cube_law), which I'm sure you're all familiar with. Muscles produce [20-135](http://downloads.lww.com/wolterskluwer_vitalstream_com/sample-content/9780781774222_Oatis/samples/Oatis_CH04_045-068.pdf) (see page 8) or [30-40](https://www.sciencelearn.org.nz/resources/1916-muscle-performance) newtons per square centimeter, or [4-8 kilograms force per square centimeter](https://www.hoddereducation.co.uk/media/Documents/magazine-extras/PE%20Review/PE%20Rev%20Vol%209%20No%201/PERev9_1_Strength-revision.pdf?ext=.pdf) (see page 2); this is (unfortunately for worldbuilding purposes) a limit.
One solution is to add more muscles in proportion to body mass. However, I don't like that solution; if I'm making a giant cat, I'd rather have a cat-shaped giant cat and not an elephant-shaped giant cat.
Another solution is to make the creature less dense. However, I don't like that solution either; it doesn't work particularly well when you're working with *really* giant creatures who'd still be incredibly massive even if filled with helium and structural voids.
I believe *my* solution is better than those two (of course; it's mine, after all). *My* solution is to make *the muscles themselves* stronger, and then to put said super-muscles into super-large-but-still-proportionate creatures in worldbuilding settings so they can exert enough force to function. To explain how I wish to implement this, a brief crash course in how muscles work is necessary.
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## Image 1
[](https://i.stack.imgur.com/SIYOE.png)
This is a not-to-scale cross-section of the smallest functional unit of a [muscle cell](https://en.wikipedia.org/wiki/Muscle_cell) - i.e. the point at which smaller structures are no longer identifiable as being part of a muscle, simply as being proteins.
Relevant things here are:
* The [thin filament](https://www.sciencedirect.com/topics/medicine-and-dentistry/thin-filament): the [helical](https://en.wikipedia.org/wiki/Helix) thing on the top. It's made of all the things below that aren't the thick filament or myosin.
* The [thick filament](https://www.sciencedirect.com/topics/engineering/thick-filament): the pile-shaped thing on the bottom. All it's made of, functionally speaking, is myosin.
* [Tropomyosin](https://en.wikipedia.org/wiki/Tropomyosin) (green wavy lines): bonded to the actin, these are to troponin as a zip line is to a person riding it. As far as I know, it doesn't really serve a purpose other than being structural material, although there are [some theories that tropomyosin is what's responsible for myosin attaching to actin](https://en.wikipedia.org/wiki/Tropomyosin#Function_in_skeletal_muscle_contraction).
* [Myosin](https://en.wikipedia.org/wiki/Myosin) (specifically, [myosin II/conventional myosin](https://en.wikipedia.org/wiki/Myosin#Myosin_classes); shaped like an orange boxing glove): tries to stick to the actin above it if given a chance to do so.
* [Actin](https://en.wikipedia.org/wiki/Actin) (unlabeled blue circles): what the myosin sticks to when given a chance. Bonded to the tropomyosin.
* [Troponin](https://en.wikipedia.org/wiki/Troponin) (red circles): stops the myosin from sticking to the actin unless bribed with calcium (more on that later). While it's labeled "troponin" here, as if it were one protein, it's actually a [protein complex](https://en.wikipedia.org/wiki/Protein_complex) made of [troponin C](https://en.wikipedia.org/wiki/Troponin_C), [troponin I](https://en.wikipedia.org/wiki/Troponin_I), and [troponin T](https://en.wikipedia.org/wiki/Troponin_T) (more on that later too).
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I would go over the entirety of the process by which a muscle contracts, but much of that'd be irrelevant for the purposes of this question. All you need to know is that:
1. I'm not going over *why* all the Ca2+ gets pumped into the cytoplasm; that's more related to the nervous system, and not relevant to this question.
2. When a muscle contracts, lots of [Ca2+](https://en.wikipedia.org/wiki/Calcium_in_biology) (1 Ca2+ is a single [calcium](https://en.wikipedia.org/wiki/Calcium) atom with a positive charge of 2 extra electrons) [ions](https://en.wikipedia.org/wiki/Ion) get [pumped](https://en.wikipedia.org/wiki/Voltage-gated_calcium_channel) into the [cytoplasm](https://en.wikipedia.org/wiki/Cytoplasm) of that muscle's muscle cells.
3. Those Ca2+ ions stick to the [troponin C](https://en.wikipedia.org/wiki/Troponin_C) in the muscles - remember that bit about troponin being "bribed" with calcium? This is that bit. Troponin C - again, remember that bit about troponin being made out of separate sub-parts? - is connected to [troponin I](https://en.wikipedia.org/wiki/Troponin_I). Troponin I covers the slot where myosin can attach to actin, and, when Ca2+ ions stick to troponin C, the *entire* piece of troponin gets twisted - C, I, T, and all. That twisting pulls the tropinin I away from the slot where myosin can attach to actin (troponin T is just there to connect itself and the other 2 troponins to the tropomyosin, and serves a minimal part in this process).
4. Once the troponin I has been pulled away from the actin, the myosin takes advantage of the troponin I's absence and attaches to the actin, producing force and moving the muscle.
5. I'm not going through *how* the muscle un-contracts; what's relevant to this question is that all force exerted by muscles is caused by myosin attaching to actin.
This process is visualized in a semi-comprehensible and again not-to-scale fashion below:
## Image 2
[](https://i.stack.imgur.com/COP8P.png)
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What I wish to do is to attach more [myosin heads](https://en.wikipedia.org/wiki/Myosin_head) (the club-shaped or boxing glove-shaped things) to the end of the first myosin head, as well as to add more myosin-to-actin attachment points to the thin filament so that those extra myosin heads have something to stick to. This is visualized in a semi-comprehensible, yet-again not to scale, poorly-Photoshopped fashion below:
## Image 3
[](https://i.stack.imgur.com/Z9Y7A.png)
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Why would I do this? Well, it stands to reason that, since myosin heads attaching to attachment points on actin are what makes a muscle exert force, *more* myosin heads attaching to *more* attachment points on actin will make the muscle exert *more* force.
Now, of course, the extra force this generates will necessitate mechanically stronger muscles, but I believe spider silk or a similarly strong [protein](https://en.wikipedia.org/wiki/Protein)-based material can cover for that, and I've [already worked around any heat-generation problems](https://worldbuilding.stackexchange.com/questions/230976/my-creatures-cells-mix-water-and-some-of-the-stuff-in-pee-to-cool-themselves-h) this might cause. I haven't troubleshot the metabolism-related issues (energy, [ATP](https://en.wikipedia.org/wiki/Adenosine_triphosphate), and oxygen supply to these super-muscles) yet, and those will likely be insurmountable. I also have to deal with the bones of a super-large creature, which is also not quite done yet.
However, I'm not really here to get a solution to *those* problems; **I'm here to ask whether or not something like Image 3 is possible via any means - for instance, and I'm just spitballing here:**
* grafting more myosin heads onto pre-existing ones to increase the number of myosin/actin pairings
* having the body fabricate a new myosin-esque protein with multiple heads to increase the number of whatever-this-new-protein-is/actin pairings
* modifying myosin II so it grows multiple myosin heads, thereby increasing the number of myosin/actin pairings
* altering the structure of actin so it has more places for myosin to attach
* altering the structure of troponin T, so it can attach to *two* troponin C/troponin I pairs, as opposed to one, letting it cover two myosin/actin attachment spots at once, rather than one
* simply adding more troponin - again, so that more myosin/actin attachment spots can be covered while inactive
**The things on this list are just ideas, not questions I'm asking about - I'm aware of the single-question policy - but I'd really like to get more attachment points on these muscles, these might be ways to do that, and throwing my brainstorming at other people might help them come up with a solution.**
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You can't get there from here.
You can always make muscles stronger by adding more muscles. When muscles fail, it's the actual fibers that break, not the connection point, so adding more connection points would just make the muscle fibers break earlier. If you replace the myosin with spider silk, then you're discarding its regenerative capabilities. If you come up with a stronger form of myosin (in which case you're making up your own rules, and the answer becomes completely subjective) then you tear ligaments instead. This is the known limitation for bodybuilders who abuse steroids. If you magically strengthen the ligaments, then the bones break.
What you're describing is a quick patch to a complicated system that has been balanced by millennia of natural selection. If you're going to do that, you need to put in a LOT more research into the prior art. You can't just add more X like you're putting more cylinders into an internal combustion engine. That wouldn't work on an internal combustion engine, either. The drive train would get shredded.
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[Apparently the earth had a methane haze in its early history](https://phys.org/news/2017-03-early-earth-hazy-methane-filled-atmosphere.html), but of course this would not have been habitable to us as the atmosphere would have been toxic. You would need enough of something to create a hazy layer but not so much that it made conditions unliveable, and it can't create too much of a greenhouse effect either. The haze would have a slight cooling effect. I don't think the haze would be so great a problem for photosynthesis that no plants could grow at all. The plants would simply be adapted for low light conditions and would favor absorption in the infra-red end of the spectrum. I imagine the world would be low bio-diversity due to the lower amount of energy absorbed into the ecosystem. I think that part is doable.
I don't know what the haze could be that doesn't create bigger problems for livability though, or how it could be produced. Is there anything that might fit the bill?
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**This is a tall order, but not impossible**
Our reference is this description of Titan's atmosphere:
>
> Like Earth's atmosphere, Titan's atmosphere is largely composed of molecular nitrogen, but it has only small amounts of oxygen and water. Instead, the moon's clouds, lakes and rain are made up of hydrocarbons — molecules composed of hydrogen and carbon, such as methane and ethane. [Latest Saturn Photos From NASA's Cassini Orbiter]
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> The huge amount of methane makes the haze on Titan "like L.A. smog on steroids," explained Scott Edgington, Cassini deputy project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
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> Titan's nitrogen and methane molecules are broken up in the moon's upper atmosphere, about 600 miles (1,000 kilometers) above the surface, by sunlight and particles from Saturn's magnetic bubble. The positive ions and electrons that are left over trigger a chain of chemical reactions, resulting in hydrocarbons — including PAHs, which are large carbon-based molecules that form from the accumulation of smaller hydrocarbons, researchers say.
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> PAHs can keep building up, aggregating to form bigger, heavier molecules that sink lower into Titan's atmosphere, eventually leading to the aerosols embedded in the dirty haze that cloaks Titan, closer to its surface, below 300 miles (500 kilometers) altitude. ([Source](https://www.space.com/21470-saturn-moon-titan-haze-cassini.html))
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It's important that you understand that third paragraph. It isn't just the methane that's the issue, it's the **sunlight** that's the issue. We can simplify this with an analogy. The methane is "gasoline" and the sunlight is the "automobile." Without the sunlight, you have a foul-smelling atmosphere, but if we ignore just how small the oxygen component is (and this simplification is so outrageous it's making angels weep!), its presence isn't intrinsically lethal (you should be thinking, "yeah, like sucking helium from a balloon, you don't just die from it..."). Hopefully you get my point.
Anyway. You're basically asking for a way to have the *aesthetic* of Titan's atmosphere without having, well, a trillion humans putting around in mobile combustion engines.
You're problem is that the methane-sunlight reaction (aka, the "automobiles") happens at the top of the atmosphere, where here on Earth the automobile reaction happens on the surface. All the particles are almost-settled to begin with rather than being created like a permanent acid rain. But that doesn't make a suspension-of-disbelief opportunity impossible.
One more thing, I'm assuming that you don't care about a haze through the entire depth of atmosphere, but really only in the first 1-3 miles. If you want the whole atmosphere, you need a top-down solution like on Titan. I'm having trouble coming up with a solution like that without the toxicity.
* One method is to have a very warm *water planet.* Such a planet, combined with the nasty winds that would occur thanks to the sun-side-dark-side cooling cycle, could believably have a permanent fog. You could also have a cold water planet with a ***lot*** of underwater thermal venting, so that the water is warm and the atmosphere is cold. Even on a still day, you have fog. If you think about it, our planet has a LOT of days that would be exactly what you wanted if the clouds where near the ground rather than 0.1-5 miles above ground. You just need them to not float so much... which might be one of the reasons why 0.14G Titan might have an advantage over 1.0G Earth.
* Another method would be to have the opposite, a nearly dry planet with almost no precipitation. And make it a bit warm. Thus, winds... thus, dust. But those winds would need to be constant. Dust is pretty heavy. No wind, no "haze."
* A third solution would be something like a jungle planet with ubiquitous high ground water but almost no standing water — and some serious pollen-creating plants. Habitable, if you have enough antihistamines.
* A solution that doesn't easily fit your criteria would be a highly volcanic world. But probably too toxic.
* Or... you could have a solar system where a massive planet is being torn apart by the sun, resulting in a trail of dust/water that falls onto your planet's atmosphere. Technically, that's a non-toxic top-down solution — but keeping the side of the planet opposite the trail of incoming dust with a permanent haze might be tricky. Allowing the giant planet to disintegrate for enough time, and yet fast enough, that it doesn't matter what the orbital orientation to your habitable planet is might also be a bit tricky. Still, suspension-of-disbelief.
Perhaps your biggest problem is that you must have that nitrogen/oxygen mix to be habitable. You can add a lot of water to that mix and still be habitable, but I suspect almost any other element or molecules would be in some quantity, toxic.
Hopefully this answer will jog the imagination of some others!
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Presented here is a map of Earth with the fictional continents resurfaced, by the Redditor "Stagman1111":
[](https://i.stack.imgur.com/Kcazb.png)
[Source](https://www.reddit.com/r/imaginarymaps/comments/964ufb/lost_continents_resurfaced/)
From left to right, the presented additional continents are Mu, Atlantis and Lemuria. It's a popular alternate history trope to imagine them being separate continents made independently of each other.
But I'd like to do it differently. In a point of departure anywhere between 157 and 145 million years ago, some of our continents (for clarity, continents like North America and Europe, etc.) had split themselves apart to create Mu, Atlantis and Lemuria. But which pieces from which continents would make the best candidates to create those three continents?
[Answer]
**Atlantis is hard, the others are...less hard**.
Mu, which I presume is to the left of North America, would come from the San Andreas fault zone, which is already basically not attached anyway and moving with respect to the continent, just in the wrong direction to produce that specific continent you want.
Lemuria would be the Indian subcontinent, which in the real world is actually moving the other way to push up the Himalayas.
Atlantis is harder because as far as I know there is no fault zone anywhere near where it should be except on the ocean floor. There is a fault at the southern tip of Africa called the Cape Fold Belt, but that would put Atlantis in the southern, rather than Northern, hemisphere and probably somewhere between the Atlantic and the Indian oceans.
Now...please note a couple of things:
1. 180 million years ago the continents were all locked together in Pangea, which was *just* starting to break apart. They wouldn't have been in the same places as now, so neither would your three lost continents
2. If these plates actually did break apart in the "wrong" direction as I described, then I can't predict what that would mean for the evolution of the earth. For instance, if India moved the other way, then you don't get the Himalays. Without the Himalayas you don't get the Gobi Desert or the dry steppes of Asia. Without those...
[Answer]
Atlantis is easy: just Iceland further south. The obvious solution is have the Azores Plateau be larger and higher so it breaks the surface.
Lemuria could be a chunk of Gondwanaland that gets pulled from Africa when India separated and started barrelling north to ram into Asia. Note that this is pretty much the origin of Madagascar, so what you can have is that the chunk that becomes Lemuria is a larger piece of Gondwanaland. Madagascar wouldn't exist, and the shape of southern Africa would be different as the large fragment was pulled out further into the ocean by the movement of the Indian Plate.
Mu, so long as you show some flexibility regarding size, also not that hard. The western bit of North America largely consists of fragments of continental crust and oceanic crust that were welded onto the North American craton as oceanic plates subducted and carried them along. What you'd want in this case is that the subduction zone occurs further away from the craton, initially creating an island arc chain that grows larger and larger through it's own volcanism and these bits of continental crust that start collecting. Then the subduction dies out leaving a welded-together terrane of the west coast. Of course, this also means that North America isn't as wide as some of the fragments that formed it ended up as part of Mu.
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So, I'm creating a world for a science fantasy setting. It has magic and such, but since it's mainly taboo to use it, I want the world's climate to be based on hard scientific facts.
My world has an axial tilt of twelve degrees, creating much milder seasons than on Earth, and expanding the temperate zone considerably. What’s complicating things is that this planet has a silicate planetary ring. For six months, the tropics experience normal light and heat energy for a planet's equator. However, for the other six months, the rings block out some sunlight, creating an average temperature similar to more polar regions. This makes the area prone to flooding, and limits what vegetation can grow there.
Now, based on my research, the shadow of the ring would create a strong front of cold air that blows towards the side of the tropics that still experience normal sunlight, creating a massive band of storms that spans the whole tropical band. It also creates currents that vary between tropical and polar temperatures, bringing about stark seasonal differences in those lands the currents are near. What I want to know is, would this planet still be mostly habitable? Or have I created a scenario where things would be far too unstable for anything to survive? I'm most worried that the planet might just be full of storms at all points, making it too turbulent for humanoid life to be sustainable. Any help you guys can provide is much appreciated!
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I suspect that life would still be possible on such a planet, however many species as we know them would not survive and those that remained would have to be very adaptable. It would depend to some extent on the origin of the ring. If life had evolved with it then it would have adapted to it. If the ring “arrived” at some later point there would likely be a large mass extinction due to climatic disruption.
One of the key drivers of the climate are Hadley cells:
<https://groups.seas.harvard.edu/climate/eli/research/equable/hadley.html>
These affect the mass movement of moisture and heat in the atmosphere north to south as well as the jet stream, rain fall patterns and more besides. If the Intertropical Convergence Zone was converted to a pole it would reverse the atmospheric circulation pattern, however it would probably take months to establish a pattern by which time it would reverse again.
<https://en.wikipedia.org/wiki/Atmospheric_circulation>
I would predict a chaotic climate with all manner of extremes of wind, rain, snow, heat, cold and draught at irregular intervals. Sea life would probably fair best as the oceans would act as some form of heat buffer, but it could easily leave the planet devoid of all or much higher life forms on land.
[Answer]
To be clear, if axial tilt is 13 degrees (and ring is not too distant), every point within your tropics will have a time of year within the shade of the ring. More extreme latitudes (towards the poles) will be unshaded.
When "shaded" you will have part of each day under the ring and part not. The closer you are to the equator the more extreme the shade is (the equator will be shaded 24/7 at Autumn/Spring meridians, making them coldest in a syncopated pattern to the dominant global seasons).
My Geophysics PhD thinks that you will see a cooling from the shade, and a moderately strong enforcement of convection around the shadow. Air in the upper atmosphere will cool and sink, leading to an outflow away from the shadow at ground level. Net impact will be a dry season when under the shadow, with strong winds.
The rotation rate of your planet will impact the telecommunication range of effects. A faster planetary spin means smaller hadley cells and more localised effects. A slower spin means the change in atmospheric dynamics will be well communicated very far from the equator (context: the Earth Hadley cells are three from equator to pole, spanning equator-to-Sahara in the first cell)
PS.
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> My world has an axial tilt of twelve degrees, creating much milder
> seasons than on Earth
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If you are going down this rabbit hole, you should be aware that there are two sources of seasonality:
1. Axial tilt: creating hemisphere-based seasons based on the 6-months when the hemisphere "points" at the local star;
2. Orbital ellipsis: Creating global temperature changes based on when the planet is literally closer to, or further from, the star in its orbit due to the elliptical nature of the orbit;
and you will need a more circular (than Earth) orbit to dampen seasonality.
[Answer]
You need more numbers, like how large are the rings, how opaque they are, and how far they are from their planet. However, I can say that I’ve found a useful method for figuring out how much of the total solar energy a planet receives, as shown in [How to Determine Planetary Extremes of Temperature from Average Global Temperature?](https://worldbuilding.stackexchange.com/questions/185703/how-to-determine-planetary-extremes-of-temperature-from-average-global-temperatu)
The answer provides a useful way to find the amount of radiation a specific latitude receives, using trigonometry.
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The moon would be similar to Earth in size and composition and the gas giant comparable to neptune or uranus.
* Will the periods of eclipse of the the giant have an effect on climate?
* What about the tidal force?
* Will being closer to the sun or farther from it on the other side of the giant have any repercussions?
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> Will the periods of eclipse of the the giant have an effect on climate?
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Very little compared to everything else.
Your moon will almost certainly be [tidally locked](https://en.wikipedia.org/wiki/Tidal_locking), meaning that one hemisphere will always face its parent gas giant, and one half will always face away. It probably won't have a moon as big as Earth's (due to gravitational interference from the gas giant) and that means that the huge angular momentum the Moon brings to our system will be absent and so tidal locking will inevitably occur.
Similarly, the [geodynamo](https://www.sciencedaily.com/releases/2016/04/160401075118.htm) that drives Earth's magnetic field may well have cooled to the point where your moon's magnetic field is reduced or absent compared to Earth, because without Earth's spin or tidal forces induced by the Moon, cooling will occur much more quickly than it has on Earth itself. Part of the reason that [Mars](https://en.wikipedia.org/wiki/Mars#Atmosphere) lost its atmosphere was the lack of a magnetic field, but we know that [Titan](https://en.wikipedia.org/wiki/Titan_(moon)#Atmosphere) has kept its atmosphere at least in part due to protection from Saturn's magnetosphere.
Lets say your gas giant is like Uranus. Uranus' [magnetopause](https://en.wikipedia.org/wiki/Uranus#Magnetosphere) is at a distance of ~460000 km from its centre. If we put your world at ~400000km, it could have a 7.6 Earth-day long orbital period, which could be called either its day or its month, up to you. That means that its periods of daylight will be long and hot, and periods of night-time will be long and cold. A thick atmosphere with [superrotation](https://en.wikipedia.org/wiki/Atmospheric_super-rotation) (as found on Venus and Titan) will help keep heat in and distribute it evenly across the world's surface. It could be quite windy!
Preventing a runaway greenhouse effect might be difficult in these circumstances. I'm not sure how it could be done. You might end up with a hot, wet, pressure-cooker like water world.
The gas giant will have an [angular diameter](https://en.wikipedia.org/wiki/Angular_diameter) of ~14°41'... that's pretty big, nearly 30 times wider than the full moon seen from Earth. It will have an [apparent magnitude](https://en.wikipedia.org/wiki/Absolute_magnitude#Apparent_magnitude_2) of -19, more than 300 times brighter than the full moon. The gas-giant facing hemisphere of your world will have bright nights every night (but for cloud cover), and wildlife will adapt accordingly.
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> What about the tidal force?
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This is usually a hideously difficult question to answer well, but as I'm assuming that your world will already be tidally locked it does simplify some things.
Real-life moons like Io interact with other moons in their local system (like [Ganymede and Europa](https://en.wikipedia.org/wiki/Io_(moon)#Orbit_and_rotation)) which tweaks their orbit to be non-circular, resulting in tidal heating. Your moon is absolutely vast by comparison, making it a) hard to tweak and b) even less likely to be near any other moons. Without these peturbations, tidal effects will [circularise](https://en.wikipedia.org/wiki/Tidal_circularization) you moon's orbit in a relatively short period of time, astronomically speaking.
It can therefore be reasonably said that there are no tidal effects, and indeed your moon would in fact experience fewer tidal effects than the Earth does from its own Moon (because the Earth rotates, and your world does not). This means the seas will have solar tides only, for example.
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> Will being closer to the sun or farther from it on the other side of the giant have any repercussions?
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Not nearly as much as you might think! If your gas giant was the size of Uranus, and it was as far from a star like the Sun as Earth is now, your moon would probably have a [maximum stable orbit radius](https://en.wikipedia.org/wiki/Hill_sphere#True_region_of_stability) of no more than 1.8 million kilometres. If its orbital plane lay in the same plane as the gas giant's orbit about the star, you'll get a difference of [solar irradiance](https://en.wikipedia.org/wiki/Solar_irradiance) of ~5% between closest and furthest points. Earth itself has its perihelion some 5 million km closer to the sun than its aphelion, and it makes less difference than the axial tilt to our experience of winter and summer.
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Footnote: here's my thinking on tidal locking.
The time for a body to become [tidally locked](https://en.wikipedia.org/wiki/Tidal_circularization) can be approximated by $$T\_{lock} \approx {\omega a^6 I Q \over 3Gm\_p^2 k\_2 r^5}$$ where $\omega$ is Earth's spin rate (~2π rad/day), $a$ the orbital semimajor axis, $I$ is the moment of inertia (which is 0.331 x the mass of the Earth x the radius of the Earth squared), $Q$ is the dissipation function, $G$ is the gravitational constant, $m\_p$ is the mass of Uranus, $k\_2$ is the Love number of the Earth and $r$ is Earth's radius. For Earth, [Q appears to be about 100](https://arxiv.org/pdf/1509.07452.pdf) and $k\_2$ [appears to be about 0.308](https://en.wikipedia.org/wiki/Love_number).
Your moon will not be orbiting beyond more than about half of the gas giant's [Hill Radius](https://en.wikipedia.org/wiki/Hill_sphere#True_region_of_stability), which for Uranus at 1AU from the Sun gives a limit of ~1.8 million km and for Neptune ~1.9 million km.
This gives a tidal locking timescale of ~130 million years for either case... sufficiently quickly that your moon could be doomed to a Mars like fate as its geodynamo cools, the magnetic field weakens and the solar wind blows the atmosphere off. *Maybe* the atmosphere will remain (as it has on Venus, though you might not want to live there) but I don't think that the tidal locking can be avoided in your scenario.
A closer moon will lock much faster, but will be protected from the solar wind. It'll also get much brighter nights on the planet-facing side, with a generally awesome view. What's not to like?
[Answer]
I suggest that yu use the Search on Worldbuilding feature at the top of the worldbulding bar and search for something like "Habitable Moons".
I also suggest that you search for articles about the possibility of Habitable exomoons by Rene Heller & others.
[https://faculty.washington.edu/rkb9/publications/hb13.pdf[1]](https://faculty.washington.edu/rkb9/publications/hb13.pdf%5B1%5D)
[https://www.researchgate.net/publication/230779373\_Exomoon\_habitability\_constrained\_by\_energy\_flux\_and\_orbital\_stability[2]](https://www.researchgate.net/publication/230779373_Exomoon_habitability_constrained_by_energy_flux_and_orbital_stability%5B2%5D)
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[Question]
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I need a plant that acts as a very relatively effective, portable source of stored chemical energy. I figure the best way to do this is to have a plant/plant-like organism that stores its unused energy as primarily adipose tissue instead of starch.
I’ve currently settled on a tuber / potato-type thing that originates from a cold place with little sunlight (prone to long winters but short, warm summers). The plant has evolved to combat its own scarcity and a limited reproduction window by “hibernating” for most of the year and sprouting rapidly when the proper conditions are met. Its ability to hibernate allows it to go dormant for long periods of time - almost like a seed - and spring back up when re-planted and re-hydrated.
The tuber itself is thick and fist-sized at the base, with a branched root system that resembles something like a mutated carrot. The roots have three layers: a thick skin, a carrot-like outer shell, and a core of unique adipose tissue. The two outer layers carry out normal root functions. The fatty core is composed of Cells with large, specialized leucoplasts that store fatty oil instead of starch.
When it sprouts, its leaves are broad to absorb as much sunlight as possible. It’s thorny to deter opportunistic predators from getting to its roots. The flowers look very similar to your standard potato’s.
The world is modern Earth-adjacent in every other way, so I’d like to know if my approach is Probable or at least reasonable, and if there’s anything else here I haven’t considered. I’m also curious if there’s any specific way this plant would have to look that conflicts with what I’ve imagined. This is also my first time posting here, so let me know if I’ve made any mistakes or need to be clearer!
[Answer]
There are plenty of fat rich plants already in our world, with the only difference that those fats are stored in the fruits/seeds: avocados, olives, almonds, walnuts and all the seeds we use for extracting oil. Those plants are present in almost any climate: from the tropical regions for the avocado to colder climates for seeds like sunflower and rape.
However the fact that all the fats are addressed to the seeds and not to the mother plants seems suggesting that those are less effective in boosting growth in an already developed organism. All the bulb based plants I am aware of store energy as carbohydrates in their bulbs/roots.
It can simply be that the additional cost for building fats from sunlight and CO2 is not justified in terms of marginal gain except that for reproductive sake.
[Answer]
**Space constraints favor storing energy as fat.**
Why would I want to convert my wealth into diamonds? I cannot buy a pizza with a diamond. I have to find someone to buy my diamonds first and give me cash that I can use for the pizza. Diamonds are poorly fungible and frangible. I love those words "fungible and frangible". Diamonds are not them.
So too fats. They are energy dense but they have to be converted to sugar before they are burned for energy and that is cumbersome.
I would convert my wealth to diamonds because I have limited space - I am escaping my country on foot with nothing but my yoga pants. I cannot cram a bunch of bills in those pants because that is a bad look. I have a water bottle containing my diamonds. Diamonds fit a lot of wealth into little space.
Plants don't need to worry about space because they are not carrying anything and they don't move, and they can usually spread out where they grow. If you have surface area to do photosynthesis you have the volume to store calories as convenient sugars.
Where plants do need to worry about space is when they are seeds. Like me in my violet yoga pants, the seeds are also escaping their country with as much as they can carry in minimal space. With space now a consideration it makes sense to package energy as lipid.
I was wondering about a situation where mature plants needed to worry about space. Maybe a place where plants grew in tight cracks between rocks and could not spread out. Maybe a situation where weight was a consideration - for example the air plankton that people love on WB stack. I can totally imagine an aerial plant keeping energy as a drop of lipid. Maybe motile plants...
ok...thinking. There are motile photosynthesizers. I predict that these photosynthetic protists would keep energy as lipid. Lets see...
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[Question]
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Now, there are monsters in this world, not exactly the most original though. You have your vampires, werewolves, zombies, wights, etc...
Monsters were always at odds with humanity, especially the Church. While monsters were physically stronger and faster, mankind had the numbers and the Church, and the Church had ~~the Belmonts~~ a family of nobles who more or less dedicated their existence to eradicating monsters in !Europe (! means NOT. In context, Europe with the serial numbers filed off), and they were legendary at it, though no one else hunted monsters, so there's that.
One day, however, Mephistopheles (the demon lawyer, not me) decided to end this family. His invention, the MK.1 Cyber Armor proved to be sufficient, and though he killed not just the men, but the women and the children too, the Cyber Armor was destroyed as well.
Now, the SNAFU level of mankind's situation is lowered by several factors:
First, many monsters were just trying to live a quiet life and actively avoided humanity and continue to do so even now. Werewolves always avoided humans, there are many vampires that live in hiding and try not to participate in vampire society. Even among those vampires that do have armies and power, some are busy inventing better topical anesthetics, so their *"Bleed for Alucard"* blood donation campaign would gain traction, and see little use for war anyway. Zombies are just meat robots under the vampires' control.
Second is that the nanites that dwell on silver surfaces are highly poisonous to monsters and demons (they can't penetrate armor, though). The noble family and their knowledge were blown up with the rest of their castle, but this one thing is widely known.
Still, there's the werewolf equivalent of the provisional IRA who go after influential people and attempt to infect them and thus turn human society against itself until it collapses. Then, there are the conspiring vampires, the Viking vampires, and the serial-killing vampires like Jack, the DVD-ripper.
So the war still rages within, and peaceful monsters still can't hope to negotiate with humanity, as it remained dead-set on total genocide.
To be able to continue that, humans would obviously try to fill the crater that the ~~Belmonts~~ left and there must have been some roadblocks (check and balance) in place so that the family would remain the Church's Black Ops and nothing more.
**Yet, I'm still struggling. Just what pre-existing medieval organization(s) would have the manpower, infrastructure, and size to be a suitable replacement goldfish? Especially since werewolves can convert the living, and vampires can make the dead into zombie grunts.**
Tech-level is late-medieval. Humans only know that silver is poisonous to monsters, but are unaware of the nanites. Some vampires are more advanced and even have electricity, but they stay hidden enough for that to be irrelevant. Demons have advanced tech but can't interfere anymore. The DVD-ripper was a joke name by me.
Since just about every second fantasy does this, the setting is the rough outlines (so no specific people or dates, please) of late-medieval Europe, that's where the monsters are, anything beyond it is irrelevant.
[Answer]
By the Lord, the Knights of the Temple will discharge the sacred duty as they always had.
We forswear spouses,
we relinquish our mundane fortunes,
we train for the fight.
!Belmonts were favoured by the Church, yet the wheel turned, and their guarded secrets perished with them.
It is upon us, brothers and sisters of the faith, to carry on the Good Fight.
I, Jean Jaques Robierre Cheval d' BirthTown, Grand Maestre of this Holy Order, do commission the creation of a select group. They will fight where Angels fear to tread.
[Answer]
**Different monsters come to help!**
The third season, and plot threads from season 1 were wrapped up definitively in season 2. But your show got renewed! How to inject new energy?
New monsters! For your scenario, I propose underworlders: fair folk because they are sweet eye candy with glowy magic and people will click on your trailer to see what those good looking and superbly well dressed folks are up to. Plus the fair folk are an unknown and chaotic quantity. Are they allies of humans? Is that one in the violet seeing someone? Why do they want to help humans fight monsters? Are they actually helping humans fight monsters? Do you think that one in the violet would like Thai food? Because there is a great place I know.
Yes yes; elf fair folk supermodels from the underworld will come help fight monsters with glowy magic, kung fu and under worldly weapons. People will mostly not be suspicious of them because every single one is smoking hot. There may be something else going on. Maybe that one in the violet with the violet eyes will confess the elf plan after being plied with pad thai and falling in love with me.
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The technical challenges for [Breakthrough Starshot](https://en.wikipedia.org/wiki/Breakthrough_Starshot#Technical_challenges) list the huge amount of power required for accelerating a solar sail to interstellar travel speeds and the precise targeting of laser beams of that energy as difficulies.
On the other side, laser emission from deep space [are not unheard of](https://dailygalaxy.com/2018/05/strange-extraterrestrial-laser-signal-detected-at-the-heart-of-the-spectacular-ant-nebula/)
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> astronomer Donald Menzel who first observed and classified this particular planetary nebula in the 1920s (it is officially known as Menzel 3 after him) was also one of the first to suggest that in certain conditions natural ‘light amplification by stimulated emission of radiation’ – from which the acronym ‘laser’ derives – could occur in nebulae in space. This was well before the discovery of lasers in laboratories.
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Being able to detect the laser emissions as such great distances (8000 ly) will require immense level of power at source (immense by the measure of what humans can control today), so lasing will happen accross large optical paths in an actually very rarefied [nebula gas](https://en.wikipedia.org/wiki/Planetary_nebula#Physical_characteristics) (roughly one light year across with particle densities of 100 to 10,000 particles per cm3)
Closer to home, however, we have - kinda readily available - higher gas densities in higher percentage of excitation/ionization.
1. Can one use the Earth's [aurorae](https://en.wikipedia.org/wiki/Aurora#Colors_and_wavelengths_of_auroral_light) as a lasing medium? (IR and VIS)
How about Jupiter's? (UV)
2. could Sun's corona act as an acceptable lasing medium? If positive, in what wavelengths?
3. is there any other medium inside the Solar system that may exist in "pumped enough state" to support lasing?
4. if one can use any of the above as lasing media, what are the challenges of approaching the things from this angle for a solar sail propulsion of the Breakthrough Starshot kind? Examples (but please feel free to list any other challenges one may plausibly think):
* precise focusing may be a problem, but only if one cannot generate enough power for the focusing to not be an issue, at least on the acceleration leg inside the Solar system
* radiation wavelength may impose some special approaches be taken in the construction of the solar sail.
* if a non-Earth setup is necessary, one will likely need to place the starting point of the solar sail closer to the body used for lasing. What challenges would this create?
Note: this is "science-based" - speculations are encouraged as long as they are *plausibly based* on scientifically known facts (of course, the answers are not required to pass the review process for publication in a science journal).
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> could Sun's corona act as an acceptable lasing medium? If positive, in what wavelengths?
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# Possibly (see [paper](http://laserstars.org/pdf/1976Ap&SS..45...87V.pdf)).
You need:
* a very hot star (20000 to 50000 K)
* with significant He content
* also, a star with important stellar wind to create a medium density gradient.
So, basically, a Population I [Wolf-Rayet star](https://en.wikipedia.org/wiki/Wolf%E2%80%93Rayet_star). When those conditions are met, then the star's plasma sheets, or for relatively colder starts its coronal mass ejections, can establish a lasing regime.
Expected wavelengths are in the blue-green parts of the spectrum, but ultraviolet (320.3 nm) is also cited in the paper.
The problem I see is that to use a WR star as a propulsion source, **you must be located on a planet orbiting that same WR star**, which would be not at all healthy.
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