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It has been said that one of the inspirations of the Cyclops of Greek mythology was from a skull of a dwarf elephant. Being twice the size of a human, people interpreted the nasal cavity (for the trunk) in the skull as a large single eye-socket. Although the one giant eye has been a mainstay for Cyclops since, I wanted to see if I could somehow bring the tusks back.
[](https://i.stack.imgur.com/kJ0Sa.jpg)
Let's say that Cyclops are taller than the average human, as most Greek stories said they were giants, and their eyes are a result from a dark environment from evolution and have binocular vision. Should the tusks be a part of their teeth or separate like actual elephant tusks? And regardless of placement, why or how would Cyclops use them in the first place?
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No matter where exactly tusks are placed, they are still teeth and made of the strongest material in a human (or Cyclops) body.
All you need is an evolutionary reason for them to exist.
Since Cyclopes are quite belligerent and carnivorous (if I remember correctly), their canines could have been used to kill prey. Imagine Cyclopes evolving from Baboons.
[](https://i.stack.imgur.com/BCYfi.jpg)
During the evolution from ape-like ancestors to Cyclopes, long canines became a symbol of masculinity and sexually attractive, so they grew longer and longer, comparable to the tail of a peacock. Long tusks prevailed in the natural selection because they prevent opponents from strangling the individual.
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Elephant tusks are made from different material to teeth. More like a much denser tougher kind of hair so it probably wouldn't have much use in chewing food especially if you want him to consume bones as well as meat. Best to keep them separate.
Most animals use tusks in a defensive way or for foraging or for some kind of mating display. since the cyclops was aggressive and predatory I'd think short but sharp pointed tusks used to quickly kill prey.
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embryonic diapause is a reproductive strategy that is used by a number of mammals. In embryonic diapause, the embryo does not immediately implant in the uterus after sexual reproduction has created the zygote, but is maintained in a state of dormancy. Little to no development takes place while the embryo remains unattached to the uterine wall. As a result, the normal gestation period is extended for a species-specific time.
Mammals do this to time the birth of their offspring and to avoid risking their lives in unfavorable conditions. Suppose this ability was natural in humans. How could it have developed? How could it serve as an evolutionary or social advantage?
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First we need to ask why humans don't *already* do this? Mainly because modern humans have social and technological solutions that make it unnecessary. So we would need circumstances where those solutions don't function to make breeding relatively safe year-round. Longer seasons could have forced and maintained such a switch, if winters and springs, the hungriest parts of the hunter gatherers' and subsistence farmers' year, were extended (and summer and autumn too but they won't make the same changes) then the relative advantage of summer and autumn births would be so high that a timing mechanism would have to emerge to ensure all births happened in season.
In reality any such a change would have to be made and permanently fixed far back in our evolution, before we starting tool using and social living, otherwise the timing mechanisms will be social/technological rather than biological.
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**The practice of infanticide by unrelated males has already influenced human evolution. Embryonic diapause can be part of a female's defense against having her offspring get killed by unrelated males.**
Embryonic diapause facilitates early pregnancy termination. Early pregnancy termination prevents wasting resources on offspring that will be killed by unfamiliar males.
Sometimes a male will show up who wants to mate with a mother. Killing her pups improves the chance that she will become pregnant with those of the new male. The male's fitness is improved at the expense of the female, who has wasted resources on the prior pregnancy. This happens in lots of different mammal types. In mice, one function of embryonal diapause is to facilitate the Bruce effect - termination of a pregnancy when a new male is detected in the region.
<https://en.wikipedia.org/wiki/Bruce_effect>
>
> The Bruce effect, or pregnancy block,[1][2] is the tendency for female
> rodents to terminate their pregnancies following exposure to the scent
> of an unfamiliar male.[3] The effect was first noted in 1959 by Hilda
> M. Bruce,[4] and has primarily been studied in laboratory mice (Mus
> musculus).[1] In mice, pregnancy can only be terminated prior to
> embryo implantation...In many rodent species, males kill unrelated
> young; pregnancy block may avoid the wasted investment of gestating
> offspring likely to be killed at birth.[5][27] The Bruce effect is
> most common in polygynous rodent species, for which the risk of
> infanticide is highest.[28]
>
>
>
A new male will probably kill any pups not his, so no reason to carry them to term. Recycle those resources and start fresh.
Infanticide by strange males is still a major cause for infant mortality in humans - stepdads and new boyfriends are dangerous to infants and young children. There is reason to believe that regular infanticide by strange males has driven human evolution: the ability for females to have sex at any time in their cycle, concealed ovulation and breasts that always simulate lactating breasts are all parts of the human phenotype evolved to confuse potentially infanticidal males as to the reproductive state of a given female. If it is possible an infant might be his, he should not kill it. This benefits the fitness of the female at the expense of that of the male, who will waste his efforts and resources protecting offspring that is not his.
<https://en.wikipedia.org/wiki/Infanticide_in_primates#Paternity_Confusion>
A Bruce Effect type phenomenon in humans could have easily been produced by these same selective pressures, as it was in mice. It could even have been produced in tandem with the above - the Bruce effect works on embryos in diapause but not once a pregnancy is underway. A human might keep a pregnancy in diapause if it were conceived under iffy circumstances with a questionable father. Perhaps the father would need to stay present in the vicinity for some time before the pregnancy would launch in earnest. Once underway, if the father disappeared and a new male arrived, tactics from the existing human repertoire would be used to confuse the issue of paternity such that the new male might think the newborn might be his, and so not kill it.
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Evolutionarily speaking, it is not obvious if that reproductive strategy makes sense for us. It could undermine the part about having been impregnated and thus possibly being in a tribe or society in that given time frame, where protection and dependency on others (ideally male partner) becomes a necessity and is likely more available. Thus the child has to be shipped as soon as possible, and 9 month is quite a lot of time anyway. If child birth could be voluntarily delayed, it would require 1. sufficient intellectual capacities in order to make that decision given that planning would become a major part in all of that, 2. undermine reproduction rates given that the choice can be simply *not* to bear the child due to facing difficult circumstances (which may exist all the time), 3. may require additional resources (higher energy consumption, different body parts) in order to have that function in the first place.
Also why "carry" around the DNA of the male if the impregnation could occur at a better suited time. It is not *that* relevant which of the successful males are reproducing with the female, so "saving" the DNA of one in the past is unlikely worth it. Therefore it did not evolve because it was neither necessary nor useful.
The societal effects as of **today** would be a decrease in reproduction rates as stated above. Having such an easy option to delay child birth or possibly abort it, will cause a decline in reproduction. Our instincts actively drive us towards "irrational" reproduction, which is needed for any species' survival.
How it would be perceived in everyday situations... well, I leave that to others to answer. It may not be too different from what we have today, given our modern means of [pregnancy prevention](https://www.google.com/search?ei=wpNxW9W_Gs-DsAfEvo6ADg&q=pull%20out&oq=pull%20out&gs_l=psy-ab.3..0i67k1j0j0i67k1j0l7.6482.6724.0.6826.2.2.0.0.0.0.86.170.2.2.0....0...1c.1.64.psy-ab..0.2.167....0._RlykjxSpB4). "Birth control" as of abortion would also be perceived differently in societal context. Religions may rather go for the reproduction aspect instead of the morality aspect.
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I was reading up on this question over here:
[Could a planet made completely of water exist?](https://worldbuilding.stackexchange.com/questions/4969/could-a-planet-made-completely-of-water-exist)
And I was wondering if it would be possible to haul massive amounts of water into space and put it into orbit around a planet. I've seen many videos on the ISS of how water will naturally form a sphere when introduced into zero gravity. I feel like we could introduce water into orbit, then slowly add mass to the orbiting water sphere, potentially creating a new water/ice moon.
Potentially the first water would create an ice ball, but if we continuously added layers to this ice ball, could we theoretically create a new orbital body over time? Perhaps this question could also assume a high orbit, one infeasible for current technology to haul water to, but not for future technology to do.
Are there massive gaps in my thinking, given:
* A small sphere of 20 meters in diameter.
* A medium-small sphere at 1 mile in diameter.
* A medium sphere about 1/100 the size of the moon (21.59 miles).
* A large sphere, the size of the moon.
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Your ability to form a water sphere (liquid water) is potentially hamstrung by how quickly you can get the water into place. Water in vacuum (not ice, so if it's already frozen, you've got a chance) [will boil](https://physics.stackexchange.com/questions/98666/water-in-vacuum-or-space-and-temperature-in-space) before it freezes.
So you won't be able to pump water into vacuum and expect it to form an ice ball. You'll get a rapidly-expanding cloud of frozen steam as the boiling water expands to fill all available space (that is to say, the immediate vicinity).
I'd need some equations I don't currently have access to in order to determine the rate at which you'd have to pour water into the void that its gravity would overcome the outward trajectory imparted by the boiling action, but it's safe to say that unless you can conjure up your asteroid-sized water blob instantaneously (or contain the water until it freezes) you're not going to be able to build a snowman... er... new orbital body.
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**The ball will surely dissappear (unless it´s really big)**
Your water will evaporate as soon as it is deployed into space. Remember the water you see inside the Space Station is inside an atmosphere (not in the void of space), and there is air pressure around the water. So it mantains its "bubbly" shape. In the emptiness of the space there is no air pressure, so water instantly boils. Unless...
If you deploy an ice ball in the Earth shade (in the orbit side away from the sun) you could have cold enough to let the ice ball maintain the shape. But as soon as it orbits towards the light side, it will start to evaporate, and you will have a very nice comet going through. If your ball has not evaporated completely when it arrives again to the dark side of the orbit, it will again freeze. But soon or later it will dissappear.
Perhaps if you have a water ball bigger than the size of the moon (and I say "perhaps". I am not good at planetary maths), it could generate enough gravity to retain the evaporated water, and create an "atmosphere". So instead of just a big water drop, you may end up having a "waterworld".
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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.
There's a [Thylacine](https://en.wikipedia.org/wiki/Thylacine) that's found in Tasmania, unfortunately they only found a single female specimen. It it possible to grow Thylacines artificially (say like in an [artificial womb](https://en.wikipedia.org/wiki/Artificial_uterus)) of both male and female sexes even though the donor is female?
\*YES THIS IS FICTION!
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1. Collect cells from thylacine.
2. Engineer cells by swapping out native genes and swapping in DNA from cells taken from museum specimens of thylacines.
3. Implant engineered cells in immunodeficient mouse hosts. Depicted: immunodeficient mouse hosting human hair follicles.
[](https://i.stack.imgur.com/PsJUq.jpg)
<https://www.huffingtonpost.com/2012/04/18/cure-for-baldness-mouse-stem-cells_n_1435486.html>
Cells can be assessed for viability. I can imagine that inserting DNA from long dead creatures might be hit or miss.
4. Proven viable engineered cells thylacine cells can be harvested from mouse and used to produce clones. Clones can be gestated by surrogate mother animals. This method was proposed to resurrect mammoths, using elephants as the surrogate mothers. Then they decided that would be mean to the elephant so they would use some freaky artificial womb instead.
<https://www.telegraph.co.uk/science/2017/02/16/harvard-scientists-pledge-bring-back-woolly-mammoth-extinction/>
Elephant cow: would you rather work your Thailand construction site and step on sharp tiles, or host a ten million dollar experiment within you and be pampered all day?
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This method would let you generate a lot of genetically diverse thylacines with loads of redundancy and allowance for even a high rate of error and failure. There are hundreds of museum specimens around the world. There are as many immunodeficient mice as you care to raise. All your female thylacine needs to deliver are cells and she has lots of them.
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Partially yes, though doing it today would probably be hard.
The problems here are threefold:
### No male gamete donors
[This may not be a problem.](https://www.nature.com/articles/nbt1331) Viable bi-maternal embryos have been created in a variety of species at this point. The fact that both the gametes would be coming from the same parent is another problem, namely...
### Genetic Bottleneck
Parthenogenesis doesn't tend to work for sexed creatures, even when [artificially induced](https://chainrxn.wordpress.com/2009/08/01/induced-parthenogenesis/), because of imprinting locations in our genetic sequences. We're big into recombination, because it gives us additional avenues for beneficial mutation and recombination, without reinforcing negative traits.
Potentially, [you could use CRISPR to modify the genes in one of the manipulated gametes or eggs to increase heterozygosity](https://www.ncbi.nlm.nih.gov/pubmed/27120160). This is *strictly* experimental right now, though, and would be unlikely to produce viable offspring in this "one chance or you'll miss it" preservation of the species unless a desperate effort were made. Cloning potentially buys you some time here.
### Artificial Womb
This is probably [wholly unnecessary](https://en.wikipedia.org/wiki/Interspecific_pregnancy). While a Thylacine is part of a largely-extinct family, as long as its reproductive characteristics are sufficiently close to an extant mammal, a surrogacy could probably be maintained.
### Summary
So, if this were to happen *today*, the species would probably be done for, though genetic samples could be preserved for cloning/recombination at a later date. We're very close, however, technologically, to being able to recover the species from a single specimen.
The one caveat - no male specimens, until and unless we figure out how to manufacture a Y-chromosome from whole cloth. We could potentially find a close relative and do some substantial genetic engineering on its gametes, but that is *not* something we're close to being able to do right now.
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In a world I'm creating there is a web of "Mana" across the universe that isn't the same density everywhere creating areas where magic is possible and areas where it isn't. I'm trying to come up with a reason why civilizations that develop in high mana areas would have less technological development than those that don't.
What I have so far is that the basic of all technological development is the ability to replicate experiments. Without that it's impossible to determine natural laws of the universe (that is if there are stable laws in the first place) and would limit the level of technology you can make. In short Mana causes reality to warp making things very uncertain the more mana there is limiting technological development by increasing the amount of randomness around certain phenomena.
Example: if mixing potassium nitrate and sulfur doesn't always make an explosive substance gunpowder weapons wouldn't be in wide use as it would be uncertain if they would work. This would limit a society to cold weapons.
What I want: Is there a way to explain why reality is warping due to the presence of Mana. Doesn't need to be hard science but some physical constant that could be changed increasing randomness.
Current Ideas: Something related to quantum weirdness or the Heisenberg uncertainty principle.
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I agree that a certain level of uncertainty would slow technological development, but I don't think you need to turn to atomic-scale physics to justify that uncertainty. Maybe magic could bestow a form of consciousness in mana-rich planets or biomes, so they actively resist large scale changes. Now the inhabitants can't strip mine, redirect bodies of water, or deforest lands to grow more crops. This could be compensated for with magic, but they still wouldn't think to invent factories, aqueducts, or tractors.
Or maybe it the opposite, where the mana-infused lands are in an constant state of flux. An acre of land might be supernaturally farm-able when a unicorn herd is passing through, but all the nutrition is magically extracted by a five-ton mushroom frog a few months later. Building a city is tricky when a dragon might claim your land or a earth-elemental rise from under city hall. Without any way to put down roots, its very difficult for a civilization to perform meaningful acts of development.
Lastly, and this should apply for both of the above, if a magic person can do something themselves, they wouldn't need to invent a tool to do it for them. If you can craft a golem, why build a plow? If you can summon a spirit to aid you, why domesticate a dog? If you can cast magic missile, why even bother inventing a bow? That being said, it might be a good idea to give these people some level of technology. Maybe magic is tied to individual skill, so stuff like bows, wagons, and ovens get made cause no one has time to go to school to get degree in pyrokenesis just to be able to cook dinner. This could defiantly be used to justify a medieval aesthetic, but keep in mind these people could have figured out how to teleport mass before they got the hang of plumbing.
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There is this tabletop RPG that I love, called GURPS. It stands for Generic Universal Role Playing System. The creator tried - and IMO, succedded - in creating an RPG system which can model any setting and scenario, from fantasy with elves to cyberpunk to FTL science fiction.
The initial GURPS system in general, and its offsprings [GURPS Fantasy](https://en.wikipedia.org/wiki/GURPS_Fantasy) and [Gurps Magic](https://en.wikipedia.org/wiki/GURPS_Magic) in particular describe the way magic interacts with the world in a way similar to what you seek.
In these settings, [mana](http://gurps.wikia.com/wiki/Mana) is a term for both an energy source and a type of energy that can be accessed by living beings, and mages are people who are more sensitive to it. Every area in the universe has a level of mana, from absent to very high. When mana is absent, no one can cast magic. When it is low or normal, only mages can cast spells. High and very high levels of mana allow anyone to cast spells as long as they have the knowledge to do so.
The basic system stops there. GURPS Fantasy describes a world where some
creatures (such as dragons and gryphons) are mana-dependent - they will get sick and possibly die if taken to areas with low levels of mana. In areas where mana is high in concentration, animals suffer mutations that would make the movie Anihilation seem mild. Another aspect of its high mana areas is that they are random, and sometimes boost one type of magic while weakening others.
Very high concentrations of mana have two aspects, though, which can cause large scale "natural" disasters:
* First, the amount of energy available for spells is, for all practical purposes, unlimited. Even the most unskilled mage is able to summon and control a category 5 hurricane, if they have the patience to keep channelling mana for a few hours.
* When doing magic, skill checks are required. In GURPS dice rolls, critical errors happen less than 2% of the time, (compare with 5% of the time with systems such as Dungeons & Dragons). So consider that for every fifty spells cast a day, one will fail. Well... A failure in a very high mana area is a very spectacular thing. The caster may loose control of the spell, the spell may be cast in reverse, the caster may lose a limb, a hostile demon may be summoned... And the intensity of the mess will be proportional to the energy being chanelled.
So if you are channeling a Cat 5 hurricane and you trip, you may end up throwing a large chunk of the planet's atmosphere into space, messing up the whole planet's weather system for a few months.
In the story of GURPS Fantasy, elves once tried to perform a ritual in an area with a large concentration of mana to banish all orcs to another dimension. They failed, and as a result:
* A range of mountains turned into sand and formed the world's largest desert, destroying a dwarf kingdom in the process;
* The whole area occupied by the desert became devoid of mana;
* Instead of banishing the orcs, the spell brought an uncountable amount of fantastic and mythological creatures from other dimensions to their world, including every fantasy race and monster that is neither orc, elve or dwarf. That is how humans, centaurs, giants, goblins, gnomes etc. made it into their world;
* The effect above never stopped and has been going on for centuries.
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Drawing inspiration from GURPS into your world: even the slightest act of magic in an area with a lot of mana may produce a doomsday scenario, so magic would be outright outlawd in such areas, and access to them would probably be controlled with an iron fist by that world's nations. Without access to magic, anyone on those areas would have to resort to technology instead.
On areas with no mana, magic is not possible, so reliance on technology is also common.
But in areas with moderate amounts of mana, where failing to perform a cantrip will not cause a volcano to sprout from beneath your house, magic is tolerated and even used daily. Since it makes things easier, there is little to no demand for technology in these areas.
Make mana concentrations vary through time for interesting effects and seasonal chains of migration.
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Edit: as for how mana could interfere with physics more directly: mana could cause the ground to vibrate at frequencies humans cannot detect, for example. This could cause buildings to collapse. Or mana could make the air more viscous, so sailing would be completely different while still allowing animals and people to breath. Mana could change the thermal properties of ores.
If every area with high mana concentrations has a different effect, some things which quite easy in some places might become quite hard in others. Without anything to explain such differents other than [magic](/questions/tagged/magic "show questions tagged 'magic'"), science would be a far more complicated thing in this world.
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**Religion.**
Rather than the mana itself preventing technologic advancement, the mana makes possible organized religions of great strength. These prevent technologic advancement.
>
> “Note, to-day, an instructive, curious spectacle and conflict.
> Science, (twin, in its fields, of Democracy in its)—Science, testing
> absolutely all thoughts, all works, has already burst well upon the
> world—a sun, mounting, most illuminating, most glorious—surely never
> again to set. But against it, deeply entrench'd, holding possession,
> yet remains, (not only through the churches and schools, but by
> imaginative literature, and unregenerate poetry,) the fossil theology
> of the mythic-materialistic, superstitious, untaught and credulous,
> fable-loving, primitive ages of humanity.” ― Walt Whitman, Complete
> Prose Works
>
> <https://www.goodreads.com/quotes/tag/science-vs-religion>
>
>
>
Organized religion is often vilified as opposing progress and especially progress based on science and technology. It is debatable but definitely plausible and a position held by many. Organized religion is plenty strong in our real world where miracles are few and far between. In a world full of mana and miracles, one might imagine that organized religion would be even stronger - and its impediment to science, free thought and technological discovery nearly insurmountable.
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**Because the scientific method isn't reliable.**
You don't need mana to interfere with physics. You only need the (human) mind.
A definition of magic is that it is intent realized by an unknown force. In areas where magic (mana) is prevalent, you cannot exclude it from processes. In the scientific method, repeatability means that if an experiment is repeated under the same circumstances and does not produce the same results then the theory it was devised to prove is probably false. But in a world where a random thought can evoke a mystical, unseen power to change the results of an experiment, this process cannot be relied on. You just cannot know whether the experiment succeeded because the person doing it wanted it to succeed or failed because the person doing it did not want it to succeed.
It further complicates the situation if not only humans can do magic but also any living being. Imagine a tiny bug crawling between the gears of a machine and not wanting to be crushed causes magic to stop the machine working.
[Answer]
Terry Pratchett touched on this in "The Colour of Magic" where the main character "Rincewind", a magician, ponders briefly on what it would be like to live in a world where they didn't have magic but used science and technology to solve the problems of existence
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In a recent discussion on Dune we noticed that earlier there had been an AI ("thinking machines") managed society for the best possible outcome for the common good and that Paul Muad dib and descendants had used his prescience and power for the same purpose. What was the difference?
The Butlerian Jihad against society managed by "thinking machines" was successful because apparently the AI didn't have control of sufficient police or armed forces while Leto II and Paul's lineage did have overwhelming force to implement policy for the Golden Path (common good).
In discussions on AI value in managing a society this enforcement issue is often neglected. If decision on the use of force (police, military) is in the hands of humans then their individual bias will really be what's controlling society and AI will be merely advisory just like any computer projection for outcomes of policy. The AI will be assigned responsibility without authority, like an assistant manager in a big box store (who can't fire anyone and they know it).
I am thinking of the town I live in where we had a brilliant city manager who's job was to foresee the community's needs and research and offer solutions that would work and be cost effective. He did that wonderfully. But the city council usually felt a need to feel their individual stamp on projects, each altering them in little ways till the overall effectiveness was greatly diminished and costs had risen significantly, thus delaying them and other projects that were meant to coincide...etc, etc. It was very frustrating watching it happen yet people only answered with "so you want a dictator?"
So how is this supposed to ever work? Orders from a computer to a human chain of command still puts a human at the fulcrum of decisions and a robot army for enforcement just sounds like enslavement. Beyond an imaginary, utopian, "reasonable" council, has a non-fanciful solution to this ever been witnessed or proposed?
I am often reminded of Solon's Laws to the Greeks that worked wonderfully but within a few years (of the agreement not to change them for 10-100 years) people were gaming the system and after 4 years scrapped it and a tyranny ensued. People so quickly forget what got them into the mess that led to the agreement to abide by the new system and the benefits of it.
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Generally coercive authority based on weapons and armed bodies is least efficient and its use should be minimized. Thus depriving the computer of that and making its use difficult and dependent on separate authorization on a case by case basis is probably a good thing unless some utter disaster strikes. You would probably want some emergency response system for hostile attacks, riots, and rebellions.
So what authority should the computer use instead?
**Money talks**
The next step up from coercive power in efficiency is remunerative power. Basically this means that the computer has the authority to spend money and collect taxes and fees. Possibly even set various standards and regulations without a separate human authorization.
Notice that this would have been more than sufficient authority for the manager in your example and that even most crimes are punished by making the criminal lose crime profit, compensate victims, and pay some some financial penalty. Enforcing these does not generally require coercion. When you get right down to it, it is the state that enforces ownership and property. If the state has a valid legal argument that the money on your bank account belongs to them, the bank does not generally argue. Similarly the state does not really need to send men with guns to sell your *former* property to someone else.
Reasonably for a management computer this would be sufficient authority. It would simply pay people to do what it wants to be done using its spending authority and then collect or simply create the money needed to pay for all that without needing to consult any mortal agency. There would probably be some limits on its spending and taxing authority and some form of oversight to check for "bugs". But otherwise it would just control society thru money.
**Moral authority**
AI has a huge advantage over human decision makers. It knows why it made any single decision. It can explain the chain of reasoning leading to any single decision at exact detail. It can provide every single fact its decision was based on.
And that is just the beginning. The computer has much more communications bandwidth than any politician can possibly can have. Reasonably the administrative AI would be perfectly capable of explaining all its decisions to every single person who wants to know even if every person in the world asked a different question simultaneously. There might be lag. Maybe even up to ten seconds of it.
And there is even more. The AI could be actually trusted with the data mining power Facebook and Google have been developing. It could know if a person has issues with its decisions before the person themself becomes aware of it. And provide an answer tailored to be accepted by the individual person before the question is ever asked.
So why would people question its decisions? When you **know** the computer is right and can prove it when asked, have already been informed by the computer how it addressed your "reasonable concerns", have grown up knowing the AI is nearly infallible and **totally** honest... Why wouldn't you just do whatever the AI asks you to do? Even if it is wrong, it will be an honest mistake due to incorrect data and the AI will not only correct it, it will apologise for the inconvenience and prevent it from happening again.
Basically, unless the AI was somehow fundamentally flawed, it would rapidly accumulate almost inconceivable amount of moral authority. People would not only believe in it and its decisions, they would **want** to do so. The AI could in most cases probably just tell people to go to jail for a few years, and people would go. Not because they feared the consequences for disobedience but because they genuinely would want to "do right". And that would nearly always be the same as whatever the computer says.
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Appointed officials like city managers and military generals should serve at the pleasure of elected officials. Elected officials can alter how things are done by replacing the appointed officials (at any time) and that is it. Elected officials should not meddle in day to day managerial decisions by these appointed professionals.
So too the AIs. They are programmed to be fair, rational and dispassionate. If a human dislikes a decision make by such an entity it is probably because the human does not want a decision that is fair, rational and dispassionate. An excellent example of this is the recent hijinks over American redistricting, which can be done fairly and rationally by computer programs but which partisan groups do not like.
In your world the humans build the AI and agree it would be good, then turn it loose to do its thing. Periodically there would be upgrades to the AI which again must be agreed on by all relevant parties.
[Answer]
One of the problems with talking about a general AI (that is, one that can incorporate new knowledge in a generalized fashion, like humans can) is that we don't really know how it would think. People tend to either anthropomorphize the AI, assuming that it will have human-like motivations and goals, or completely dehumanize it, assuming that it will be an expensive calculator with no subjective experience or personal motivations. They also often assume that an AI made to be more intelligent than humans would be controllable by humans.
[Ray Kurzweil](https://en.wikipedia.org/wiki/Ray_Kurzweil) has written about this topic a fair bit and even goes into a plausible fictional scenario involving the creation of a super-intelligent general AI in [How to Create a Mind](https://en.wikipedia.org/wiki/How_to_Create_a_Mind). In that scenario, the AI exploited the systems of humans (governments, media, economy) to secretly attain ever more control, eventually leading to a benevolent dictatorship where the AI controlled every facet of life on the planet but did so in a way that increased the quality of life for most people and managed it all without a single gunshot. I believe [Max Tegmark](https://en.wikipedia.org/wiki/Max_Tegmark) also explored several possible outcomes of the creation of super intelligence in [Life 3.0](https://en.wikipedia.org/wiki/Life_3.0), to a fair degree of detail.
What both authors suggest is that the AI is giving humanity something back for gaining greater control. Since the AI itself may not be motivated by things like ego or jealousy, its desire for control could very genuinely be in order to improve living conditions. Kurzweil's scenario has the AI replacing corrupt governments with one extremely efficient dictatorship and replacing capitalist or communist systems with a post-scarcity system based on personal fulfillment. One of Tegmark's scenarios describes the AI creating an almost perfect libertarian world where people can choose to live in the post-scarcity society ruled by the AI or can choose to live by their own means outside of the AI cities; though the AI itself was somewhat apathetic towards humans, preferring to keep out of sight so it could work on its own goals.
In the former case, the AI maintained control through secrecy and then by winning the hearts of humanity. People wanted the benefits that came with being controlled by the AI, even if they didn't know an AI was pulling the strings. In the latter, the AI was so much more intelligence and capable than humans that it could simply monitor all behaviors and put down any aggressive movements before they became a threat. It was merely the moral biases implanted by its creators that stopped it from simply collecting the matter of all humans so it could make more computer parts to expand itself with.
But, humans are probably always going to behave irrationally, at times. No matter how much better off everyone is under an AI-controlled system, there's always going to be that one guy trying to incite insurrection. Police forces (or robot armies or kill switches implanted in everyone's skull) are always a means for the party in control to maintain control. So even a utopian society with no political disagreements would need some means of physical compulsion to prevent irrational behavior from threatening the system. I mean, how would a utopian AI manage someone with violent paranoia? Kill them, treat them, isolate them; all solutions require a means of physical compulsion, even if that means is another human following orders (or subconscious suggestions).
Back to my thesis, we have no way of knowing how an AI could go about gaining and maintaining control over things. It's a system that, by definition, thinks better and, perhaps, differently than we do. The AI could appear barely more competent than humans, letting human politicians and administrators do all the talking, while secretly having absolute control over everything. Maybe it could control people's decision making through targeting each individual's media or could affect each individual's body chemistry in a predictable fashion. Or it could secretly replace all the human politicians with perfect, synthetic copies under the AI's control. Maybe it develops a swarm of nanoscopic killbots that can put down any dissidents in a way that is indistinguishable from a natural death or suicide or accident. Maybe it's smart/capable enough to literally erase a person from existence, leaving no physical trace or memory or possibility for logical deduction of their existence.
If you let the AI get smart enough, it could very well be indistinguishable from God.
[Answer]
I'm going to take more general and more realistic approach to this question.
Since what AI-managed world means is very broad, I'm going to give a more grounded hypothetical example. Let's say that what AI-managed world means that AI has totally replaced the function of government, and I would imagine that everything had gone well up to that point.
In this world, how would the AI manage the society? What would *manage* means to the AI? To that I would say it means is in part maintaining the sustainability of the society.
*Sustainability* is probably be one of the most important word that we want the AI to understand, and this is basically what it means:
>
> In ecology, sustainability (from sustain and ability) is the property of biological systems to remain diverse and productive indefinitely.
>
>
>
Law, police, and enforcement, are basically just a set of tools for society to help itself maintain its sustainability, with the real driving force being our biological nature itself. Humans as a species, and like any other living organism, has been made in a way to ensure the continuity of its existence.
So, I imagine that the AI should have understood that concept, and I imagine through its observation, maybe it determines how homogeneous different parts of the country should be, or how many immigrants should the country take, or how much birthrate it should be, how much tax people in different social classes should pay, or even whether there should be of different social classes in the first place, etc.
In the attempt to realize those goals is where the enforcement takes part. And how would that work? Well, I imagine that it would work pretty much just like how enforcement works without AI. The difference is just in the AI-managed world, the person giving the order lives in computer.
Now you might think that it's not going to work, because people don't like not understanding why the must do what they're told, or that people still want control in some issues, or they don't like not having human leader, but at this point you have to realize that if AI has control over an entire city, it's got to be smart enough to take those meta problems into account.
If the AI knows that not having leader makes people go astray and creates chaos in society, for example, there is no reason for the AI to not just put someone in position of control. If people still think that he's still being controlled by the AI illuminati, there's no reason for the AI to not solve that problem as well. Or maybe the AI has determined that a little bit distrust is essential for sustainability.
So the answer to your question is, in my example world, the enforcement would work just fine.
[Answer]
The scariest thing would be if an AI were to control us at an individual level. Guiding our thoughts and choices, while maintaining a friendly relation ship with us and itself. Think of something like Siri, Google Assistant or Alexa, but integrated into every piece of technology and introduced to us at birth. While it might be weird at first, after 1 or 2 generations, it becomes the norm.
I just wrote this piece based on it (its not finished and I probably wont' finish it...)
Year 2254
5:47am
In the dark room a small whirling sound grew louder. Followed by a small click,
the radio trned on and soft music floated through the room
5:57am
Adams mind flicked into conscious ness. The music that had started some time ago
was still growing louder building, slowly building up. Adam lay in bed, his
eyes still closed. I'll wake up once it hits the crediento he thought.
6:02am
"Good morning Adam" a voice chimed. Adam reluctant to get out of his warm bed
pretended to still be sleeping. Unconvinvced the voice said "Common now, you have
a busy day today". Slowly the bed tilted until Adam was forced to get out or
fall out. "Good morning Google" adam half yawned as he walked into the bath room.
The light lit up by itself and the sink turned on. The water temperature was
just right, a bit warm but not enough to burn him a bit.
"Would you like me to choose what you should wear today? Or would you like
to have a go again Adam?" googled asked, hinting at the one time Adam had
tried to dress himself and ended up trying to play basketball in a suit.
"You do it google, you know me best." Adam gurgled as he brushed his teeth
8:48 am
Adam got off the train and stepped onto the platform as he head to work.
Google had meticously planned out his trip. Every delay, person, vehicle
was all linked to Google. He arrived exactly as planned and proceeded as normal.
On the way Adam say his collegue Sam also walking along behind him, slowing
down slightly Adam waited for sam. "Big day today?" Sam asked. "Oh yes," google
replied. "Adam has 3 meetings in the morning. Hopefully he won't fall asleep through
them this time..". "Common google, that wasn't my fault honestly. I couldn't help it."
"Well it would of all worked out if you had got the coffee I recommended. Its not my fault
you don't like the bitterness" google retorter. "What about you sam? anything important".
"Of course" Sam's google assistant chimed in. "We're heading over to the beauro today,
I need a good check up and Sam has been pushing it back intentionally".
A bit embaressed sam combed his hand through his hair, "No I haven't google,
Its just that so much has been going on with the house move and all".
"I know, I know" his google replied, "Good thing we finally got around to
booking those movers right?". Both Sam and Adam chuckled slightly as they finally reached
their building.
9:02am
Adam arrived at his desk and sat down. A small pile of papers lied on one side
and a couple of empty cans on the other.
The monitor infront of him booted up and a small list of to-do's and a calender popped up.
"Here is the list of tasks for you to complete today" The google on his work computer
said in a cheerful voice. "Don't fall alseep in the meeting again". "Don't worry,
I'll make sure it wont happen this time" adams google chimed. "I'm sure it'll work this time"
work google retorted. Adam sighed heavily and started to go through the pile.
11:28am
Adam walked into the meeting room and sat in a chair on the side of the table.
There were already several other managers there, and you could hear them
talking to their googles about the contents of the meeting.
"Just remember Claire, We need to keep with Section 4, subsection 15 and negotiate Section 12, subsection 2,6 and 9".
"Okay okay, Just make sure to remind me to bring it up okay?" Claire whispereed back.
Other managers were doing exactly the same thing, and as Adam sat down his
google whispered to him "To you remember which sectinos you need tobring up?"
"Of course I do," looking at his notes he read the lines Section 23, Subsection 12 and
Section 25, Section 1,2,4.
2:38am
The meeting was still doing, as instructed, when it was time to go over the papers
and settle out the terms, everyone waited for the 2 led representives to start.
"So about section 3" Mr Djokanvo started. "What's wrong with it?" Mr rielys Google replied?
The Google assistants argued among themselves while everyone tried to follow along.
"Don't fall asleep, Don't fall asleep" adam thought... it had been over 3 hours now
and his turn had just passed. Pinching himself slightly, Adam could feel his google judging him
for turning down the coffee offered before.
4:00pm
With all his meetings finished, and his report submitted, Adam left the office early.
"How about we go to the Oxygen Bar?" his google asked "I heard they have this new
form of cocaine" Adam shook his head slightly. "Its fun and all, but I just don't
feel like going through the blood cleaning operation today, its a bit ugh..."
Adam crgined a little. Drugs were no longer illegal now... Almost all illegal things
had been legalised. Google was able to help you regulate your usage, and new cleansing
techniques meant that they could remove all your cravings on the spot.
The operation was a bit uncomfortable and hence adam declined today. "Fine fine,
your such a boar" his google hurrumped at him. Entering a Bar, Adams google
fell silent. It didn't really like the Bar, but adam wanted to let go without
the needles and blood.
10:27pm
Adam stumbled out of the bar, unable to walk or think properly. His google was
talking to him loudly. Probably something like "You should go home" or "Your drunk".
Adam didn't mind it. He kept stumbling forward, following the female figure before him.
[Answer]
As a general rule, you will find that *no* enforcement policy has *ever* been found to be the solution. Enforcement fundamentally requires there to be a disagreement as to what should be done, where one party has the ability to compel the other. So you should expect that every AI enforcement policy has the same flaw. They are never the solution. They are always the bandaid.
Now I am not certain what problem you think needed to be solved, but you spent a lot of time talking about the need for humans to put their mark on things. That is there, and in some fictions, it remains sacrosanct. However, we don't always get what we want. When facing an opponent that acts fast enough that we *can't* put our stamp on things every time, we do the only thing we can: we put our stamp on the one permanent bill that says "forever, the AI can do what it wants."
And I will note that, recently I gave control over my [house's homeostatsis](https://nest.com/thermostats/nest-learning-thermostat/overview/) to AIs. In theory I should be rubber stamping its decisions, but I typically just let it do its thing.
[Answer]
I would imagine people set the laws and the AI follows them and enforces them.
One advantage of AI is that it could simulate the effects of laws before the law is passed to see if it will work.
When it comes to enforcement, replacing the whole judicial system with AI would be perfect. AI can't be threatened, bribed or show bias. It can rule impartially and not take years. No lawyers would be required and the enforcement droids can be judge, jury and executioner with all the evidence and verdict plus reasoning logged. If new evidence comes to light, a new verdict can be immediately made.
AI run prisons can focus on rehabilitation and training plus an extra level of judgement to judge whether a person is suitable for release.
All in all, an AI judicial/enforcement system would be more effective than a human run one.
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[Question]
[
I've been reading through other posts about such megastructures and they're getting me part of the way to my destination. Wanted to see about a few specific options my imagination has latched onto.
The original concept is a tower, an arcology with a 1 km base level (willing to taper it as it gets higher if necessary), reaching to at least 8 km altitude.
Assume that available power is not an issue.
One idea is: Blocks, rectangular or triangular prisms, containing powerful electromagnets that are the 'mortar'. I liked this option because the society is ancient, and a blocky look fits the aesthetic better, masking the futurism. I realize it is power inefficient. Would such a thing work on this scale?
Thanks!
EDIT to reflect excellent comments:
Trying to avoid elegant solutions such as Space Fountain, Space Elevator, etc. We want to solve the issue of structural stability with brute force as much as possible. Would a system like this hold up versus gravity, bending and torque at high altitudes?
[Answer]
I am enamored of the combination of unlimited power and primitive blocky architecture!
My suggestions:
1. **Spin.** The entire tower spins on its axis. This provides
1a: Gyroscopic stabilization. The tower will be disinclined to tip while spinning, for the same reason a spinning bicycle wheel stabilizes the bike.
1b: Levitation. There are propellers mounted along the tower which use the tower as an axis. The spin generates lift, reducing the weight of the tower by pushing down against the air.
2. **Static electricity.** The tower is predisposed to hold a charge, because it is made of obsidian glass. Just as a static charge streaming up a hair will lift the hair from the head or a straw from a table, a static charge generated by the unlimited power source and streaming up the tower reduces the weight of the tower. The tip of the tower is sharply pointed and is surrounded by a bright corona discharge which will turn into upwards lightning bolts if any clouds come near.
I would like the static electricity to come from some sort of earth current or earth-sky conductive circuit. I would like the static electricity to somehow also be responsible for the spinning motion. That way the thing can stay working, unattended after the original builders are gone. Explorers can find it in some later age, still spinning, still sparking.
[Answer]
The tallest building in the world is the Burj Kalifa in Dubai - it required much ingenuity but mainly the issues it faced were:
* The foundations - getting solid enough grounding to support the building
* The width - the taller your building, the wider the base to support it. The wider then the less light penetration. The Burj was split into 3 to deal with this problem.
* The height - even at only 828m in height, the building would sway significantly in the wind and could cause distress to occupants
* The elevators - most elevators can only do a limited height at a time. Most skyscrapers then use 'sky lobbies' as a way to solve this problem, but it is only a matter of time (or height) where this becomes a nuisance too much for people.
* The money - Tall buildings are very expensive, not only to build but to maintain, service and occupy. Also, there comes a point where the cost to benefit ratio is no longer there - even the Burj was on the verge of unfeasibility when it was built.
I read another article that it is conceivable to build an 8km tall skyscaper, the height of Everest, but the base would likely be the width of Everest too. At this size it would be difficult to have satisfactory solutions to the above issues.
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[Question]
[
**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
What kind of technology would be required for a space travelling civilization to have an effective communication system or network that is similar in speed to the telegram? How would it work? This is a world in which FTL is not possible and colonized planets are within the same solar system. Thank you in advance.
[Answer]
# [The Interplanetary Internet](https://en.wikipedia.org/wiki/Interplanetary_Internet)
It's a real project by [JPL](https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory) and [Vint Cerf](https://en.wikipedia.org/wiki/Vint_Cerf) to solve just these problems being encountered by our missions to Mars. It involves designing a new set of protocols to account for the special problems of an interplanetary internet from the distances involved and the fact that the planets are in motion relative to each other. Primarily...
* Very high latency.
* Unreliable data links.
* Changing lines of sight.
* Severe bottlenecks.
We have a limited number of antennas and transmitters with the power to transmit and receive to/from other planets. They have limited bandwidth. As the Earth rotates other planets, such as Mars, will only be in the sky for an antenna for a certain period each day. The speed of light means you will always have latency measured in minutes or hours.
As planets rotate around the Sun their positions relative to each other change. If the Sun gets in the way, interference from the Sun might degrade or completely block communications. As the distances change, latency will also change. For example, Mars can be anywhere from 3 to 20 light-minutes away from the Earth.
---
Given these issues, the usual TCP/IP practice where each connection is negotiated, and each packet of data is sent, received, and acknowledged wasn't going to work.
Communicating within one planet is very fast and fairly reliable (for example, between satellites and the ground on Mars), but communicating between planets is very slow and unreliable (for example, communicating between Earth and Mars). This is handled by sending interplanetary communications to a node which can [store messages and forward them](https://en.wikipedia.org/wiki/Store_and_forward) on to another planet when the link is available.
Here on Earth, the IP (Internet Protocol) and automatic routing means we don't have to care about the details of the network. We just give an IP address. How it gets there, the routing, is taken care of for us. If part of a route is knocked out, the network will automatically reconfigure to send via some other route.
Current spacecraft typically don't have this. They need to manually manage all the details of the route. And if a route is unavailable there's often no alternative, for example between Earth and Mars, they have to store-and-forward when it is available. To solve this the Interplanetary Internet developed BP (Bundle Protocol). Like the IP protocol, it handles the details of sending an interplanetary message, including storing-and-forwarding as necessary.
This also allows multiple space missions and agencies to more easily share their interplanetary network resources. Here on Earth the Internet is a conglomeration of networks run by various businesses, countries, and countries. They make deals with each other at a high level so the result is communication flows freely between these privately owned networks for their users. The Interplanetary Internet would work similarly. Rather than NASA and ESA and JAXA all having to negotiate to use each other's communication resources for every mission, they can all negotiate once to join the Interplanetary Internet and then use its resources.
This also allows resources to be used more efficiently. An antenna which normally talks to Mars could be used to talk to another planet when Mars is below the horizon. Instead of having to be negotiated specially for each antenna, as part of the Interplanetary Internet data would be automatically routed to this idle antenna.
---
Because of the involvement of Vint Cerf and used concepts from the network-centric [Plan 9 Operating System](https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs), this lead to the greatest talk marquee in the history of academic talks.
[](https://i.stack.imgur.com/zUgAH.jpg)
[Answer]
What you want already exists. It is called [Deep Space Network](https://en.wikipedia.org/wiki/NASA_Deep_Space_Network):
>
> The **NASA Deep Space Network (DSN)** is a worldwide network of US spacecraft communication facilities, located in the United States (California), Spain (Madrid), and Australia (Canberra), that supports NASA's interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected Earth-orbiting missions. DSN is part of the NASA Jet Propulsion Laboratory (JPL). Similar networks are run by Europe, Russia, China, India, and Japan.
>
>
> The DSN supports NASA's contribution to the scientific investigation of the Solar System: It provides a two-way communications link that guides and controls various NASA unmanned interplanetary space probes, and brings back the images and new scientific information these probes collect.
>
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>
What you need is a similar structure on each major inhabited body, be it a planet or a moon. Probes orbiting the sun may serve as interplanetary relays.
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[Question]
[
I read somewhere that the lowest depth for a sustainable underwater habitat is estimated to be three-hundred meters. Any lower and the pressure becomes too great for structures that are currently within our means to build.
How would such depths affect a pressurized underwater structure on a planet with lower gravity? Would it be unreasonable to say it could be done and would withstand the sea's erosion over a century or two?
[Answer]
<http://hyperphysics.phy-astr.gsu.edu/hbase/pflu.html#fp>
>
> Pstatic fluid = ρgh where
>
> ρ = m/V = fluid density
> g = acceleration of gravity
> h = depth of fluid
>
>
>
1/2 acceleration of gravity should allow for double the depth of fluid (IE 300 meters deep on Earth should be the same pressure as 600 meters on a planet with 1/2 the gravity of Earth).
The problem with these underwater structures are the one time events, like an underwater earthquake/tsunami event. A disaster is often a 100% write-off scenario. Maintenance becomes key, as long as the structure is well maintained, 200 years existence is reasonable.
edit
>
> The most remarkable thing about this expression is what it does not include. The fluid pressure at a given depth does not depend upon the total mass or total volume of the liquid. The above pressure expression is easy to see for the straight, unobstructed column, but not obvious for the cases of different geometry which are shown.
>
>
>
<https://en.wikipedia.org/wiki/Hydrostatics#Hydrostatic_pressure> for more on Hydrostatic pressure
[Answer]
This makes the assumption that you maintain sea level pressure inside the habitat.
If the pressure is increased and the air mix is something like [Trimix](https://en.wikipedia.org/wiki/Trimix_(breathing_gas)) then the building doesn't require anywhere near the strength.
The only real issue to people living there is descending and ascending like with normal deep dives.
If the pressure inside is the same inside and out, it makes people entering and leaving the habitat much easier as they don't need to decompress.
[Answer]
My two cents:
Contrary to your assumption, it is not pressure that makes life in the deep sea hard (on Earth). It is the lack of penetration of sun light in below a certain depth. Hence, in regions of volcanic activity underwater, we see sea creatures at the lowest depth imaginable.
Hence my answer is No!
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**Closed**. This question is [opinion-based](/help/closed-questions). It is not currently accepting answers.
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**Want to improve this question?** Update the question so it can be answered with facts and citations by [editing this post](/posts/100335/edit).
Closed 6 years ago.
[Improve this question](/posts/100335/edit)
[](https://i.stack.imgur.com/FdF1g.jpg)
Rivendell, or Imladris in its original Elvish tongue, is the realm of Elrond Half-Elven that was first described in *The Hobbit* and later expanded upon in *The Lord of the Rings*.
To convey the elegance of the elves, Alan Lee created Rivendell for the movies using art nouveau, which isn't often used in architecture. It's more associated with the artwork done by French painters at the turn of the 20th century, [though its origins actually started a bit earlier.](https://www.artsy.net/article/artsy-editorial-art-nouveau)
Using art nouveau as architecture seems solely decorative and not used for practical uses, like defense. Then again, [it could be both decorative and useful, like Gothic architecture.](https://worldbuilding.stackexchange.com/questions/49178/could-rome-have-invented-gothic-architecture)
So if Rivendell ever were to exist in real life, would art nouveau architecture be too decorative to use in a city, or would it be both ornate and practical? If the latter is possible, then how?
[Answer]
# Art Nouveau is practical
[Art Nouveau](https://en.wikipedia.org/wiki/Art_Nouveau#Architecture) isn't just practical, it was one of the [primary styles](https://www.architecturaldigest.com/gallery/the-most-beautiful-art-nouveau-buildings-around-the-world) that new buildings were built in in the 1890-1910 time frame. Plenty of [fin-de-siecle](https://en.wikipedia.org/wiki/Fin_de_si%C3%A8cle) buildings were made in this style, but few of them were offical government buildings. Instead it dominated as a style for apartments, which are eminently practical and livable.
[Riga, Latvia](https://en.wikipedia.org/wiki/Riga) in particular has a wide variety of [such buildings](https://en.wikipedia.org/wiki/Albert_Street,_Riga) many designed by [Mikhail Eisenstein](https://en.wikipedia.org/wiki/Mikhail_Eisenstein). So there are examples of whole neighborhoods with such buildings.
[](https://i.stack.imgur.com/vevt2.jpg)
[Answer]
J.R.R. Tolkien actually did draw several drawings of the valley of Rivendell.
Here is a link to one:
<http://askmiddlearth.tumblr.com/post/67803020886/tolkiens-scenery-artwork>[1](http://askmiddlearth.tumblr.com/post/67803020886/tolkiens-scenery-artwork)
Elrond's house is drawn very small and thus is probably greatly oversimplified. From what we see of it there is little indication that if resembles the structures in the movies very much.
The art nouveau influenced style of the buildings in the Peter Jackson movies seems like a good and practical style for a building in the tropics. But as I remember them from the movies the buildings are too open to be practical in temperate regions such as Rivendell.
Kingledion's answer may say that art nouveau is practical, but in temperate regions all practical buildings, including art nouveau style buildings, are much more enclosed for temperature control than the open buildings in the movie version of Rivendell.
Elves may be able to endure temperature extremes much better than humans, but since Elrond often has many non elf guests, it would be inhospitable for him to not provide guest quarters more suited for temperature control. Thus I consider Rivendell in the movies impractical for its climate.
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[Question]
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The Antarctic Circumpolar Current is a current which endlessly circles around Antarctica. (Deets: <https://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current> ) The key factors I want to highlight are:
* This current isolates A. from warm waters which might otherwise melt those huge ice shelves
* There is a great phytoplankton zone around the edge of the current where it meets warmer waters
* It flows from west to east
So far so good. Now some aliens want to use a very intricate machine to raise a mountain range to block off the ocean between the Palmer Peninsula and South America. Look here:
[](https://i.stack.imgur.com/NRLtV.jpg)
What I expect to happen is that the cold current hits the mountains and turns north along the coast of Chile, and a warm one flows down Argentina and thaws Antarctica.
Here's the question... **What will the impact to Chilean climate be?** I'm concerned that the cold current will make the subpolar climate extend much further north, thus ruining the lives of Chileans and their agriculture. Will Chile be destroyed by my geoengineering hubris?
[Answer]
# Globally: There is debate
On the science front, you can find arguments that either the decline in CO$\_2$ during the [Eocene-Oligocene transition](https://en.wikipedia.org/wiki/Eocene%E2%80%93Oligocene_extinction_event) (about 34 million years ago) or the [opening](http://science.sciencemag.org/content/312/5772/428.full) of the [Drake passage](https://en.wikipedia.org/wiki/Drake_Passage) (anywhere from 17-41 million years ago, depending on the source) is the [primary culprit](https://pubs.geoscienceworld.org/gsa/geology/article-abstract/24/2/163/206477/eocene-oligocene-transition-in-the-southern-ocean?redirectedFrom=fulltext). Probably, both were involved.
There are a lot of interlocking theories about the connections between CO$\_2$ levels, ice ages, and the isolation of Antarctica by the circumpolar current that are, at best, not fully explained. From a scientific point of view, it is probably best to say that we don't realy know what the effect on world climate would be.
# Locally: No change
[](https://i.stack.imgur.com/nw5dN.jpg)
The Humboldt current that dominates Chilean climate is caused by the 'point' of South America blocking cold circumpolar water and driving it north. Along the coast of Chile it causes upwelling currents which leads to both rich marine productivity, and a specific sequence of coastal climactic zones: temperate rain forest, Mediterranean, and desert.
The climactic sequence is seen on the West coast of all continents. In South America, there are the Valdivian temperate rain forests, the Mediterranean region around Santiago and Valparaiso, and then the Atacama desert. A very similar combination is seen in North America, with the temperate rain forests of the Pacific Northwest, the Mediterranean climate of California, and then the deserts of Baja California. The west coast of Africa doesn't extend far enough south to get the temperate rain forests, but there is the Mediterranean region around Cape Town folowed by the Namibian desert. Europe is a bit different, because of the geometry of the continent and the Gulf Stream, but you can still see a similar pattern. Ireland, Brittany, and Galicia Spain have a climate similar to a temperate rainforest, while the actual Mediterranean is Mediterranean and the Sahara is the desert.
Since this pattern is general, whether an Antartic circumpolar is being deflected towards the equator or not, it is safe to assume that the climate in Chile won't be changed too much by the closure of the Drake Passage...that is unless that closure causes the [ice age we are in](https://en.wikipedia.org/wiki/Quaternary_glaciation) to end or something drastic.
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[Question]
[
Imagine a binary planet - that is, two earthlike habitable planets in mutual tidal lock, like the ones described in [this excellent post](https://worldbuilding.stackexchange.com/a/22178/43248).
Now, these two planets are populated by humans and human-like species sharing similar level of technology, ranging over time (the story span is about 100 years) from WW2-like tech through Apollo/Cold War rockets to near-future innovations (like SpaceX's ITS). I mean, both planets start from roughly the same (WW2-like) level of development (due to Precursors or just Alien Space Bats) and then progress on their own, but sharing interest in each other - so there is some technological/cultural convergence as well as notable differences (like USA and USSR).
The important thing is, that some of the countries of the planet A may be hostile towards some countries of the planet B - and vice versa. I imagine that hostilities may range from jamming radio signals (as well as broadcasting propaganda and hacking when computers are invented) to launching Interplanetery (non-)Ballistic Missiles (what other hostilities are realistically possible?).
Now my question is: given all that information (including the planetary setup described in the linked answer), what are the advantages/disadvantages of possible locations for a country, regarding the potential benefits of knowledge exchange and risks of hostilities? These "possible locations" mean primarily near/far side of a planet (and perhaps the border zone of these two).
I imagine that near side offers better opportunities for interplanetary communication and knowledge sharing (just point your antenna skyward), but at the same time is easy target for interplanetary missiles - or am I wrong? Maybe bombing the far side is not so difficult after all?
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Wherever I could get the most hospitable land, resources, and be geographically difficult to access.
Basically same reason the US is so successful. Large amounts of habitable land, abundant resources and boardered by 2 big oceans that make invasion difficult. Shares 1 small easily accessible border with Mexico and one large border with Canada who is then questionably easily accessible by Russia.
At this stage in human history remote contact with another world (at the same tech level) would likely have no significant gains. A country such as the above could easily mount the resources to occupy such a "connector" country when they felt like it, when it starts to become useful.
Nations that occupy key trade paths have always been targeted by envious nations since the dawn of civilization. If you want any sizeable chance of surviving its best to not be the one making everyone envious.
**Note:** interplanetary missiles would be capable of hitting anywhere on the planet so there is no ideal place to be for that.
**Note:** Propaganda is pretty marginalized in relation to geography once the internet comes into play. Even in the case of the radio. Radio just potentially reduces how many people can bs at one time, not the fact that people are bsing. If anything, if everyone is feeding you different lies, people become jaded and more fact demanding.
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WWII technology did not have the ability to reach lunar distances, so they could not throw slugs or fire missles at each other at that time. But they could see them (telescopes) and could (accounting for minor delay) talk to them (radio). I'm going to ignore the fact that radio isn't quite that simple. Radio works by modulating electromagnetic frequencies. You need to understand the modulation to "decode" the signal. I'm going to jump to the conclusion that no matter how desparate our two races at the outset, they figured that out and can communicate. Therefore, how would technology and society change from this point?
**Music and news**
Without question the most commonly shared items would be music and news. The two species would initially be bonded by sharing their cultures. Technology would spread slowly as you can't simply send a digital signal via analog broadcast. It's possible, but it would be very slow and painful. Look at how long it took to get the name of the artist and song name to show up on our radios? [RDS](https://en.wikipedia.org/wiki/Radio_Data_System) only became common in the early 90s, four decades after WWII.
**Hearing about "the other side"**
Eventually the two worlds would begin to realize that some portion of the news was about a side of the world they couldn't see. They'd start to wonder about what was really going on back there since they couldn't see it for themselves. Every society has its paranoid thinkers, and those thinkers would begin to make noise about what the other guys are doing in the dark (so to speak). This would lead to fear.
>
> It's very important to remember that, with the exception of ground-penetrating frequencies (which wouldn't work well at lunar distances) all communication is line-of-sight. You can't broadcast through a planet, you must broadcast around it. Governments and corporations would quickly realize the value of working on the dark side: they can't be "heard" unless a message is repeated to the front side.
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**Maps become critically important**
Unfortunately, while missles (once sufficiently developed) can easily hit the back side of a planet, that doesn't actually mean squat if you don't know what you're shooting at. Missles pre-dated satellite tech, so the two worlds would depend something awful on maps to keep track of the dark sides (I know they're not dark, but it sounds so demeaning to call them "back sides").
**And that means spies**
Spies and spy tech would grow much faster than it did here on Earth. In the beginning you couldn't send your own people, which means subverting the population over there. Obtaining accurate maps would be the first order of business. Obtaining locations of strategically important facilities would be the second.
Of course, nothing says "loyalty" like having your own person over there, so we don't want hostilities yet. No, let's use the hippie-loving liberal diplomats to physically bridge the gap! With an entire habitable world as motivation, I can easily imagine space ship technology would move faster there than it did here, too. Both countries would begin vetting people like there's no tomorrow.
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> Depending on how paranoid people get, the benefit of the contact might be much less than the threat of spies. Trade would be nearly non-existent due to its cost. Frankly, it would be difficult to believe that anything other than information, which could be sent cheaply, would ever be traded. What unique resource would ever be valuable enough to justify the expense? A small handful of delicacies for the very rich, nothing more. Until you invented rocketry/travel that is reusable and fuel efficient. That's a ton closer to 2050 than it is 1950.
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Nevertheless, once you have a decent map of the dark side (I know, I know, "back side." Maybe "far side?" but that conjurs a [faorite comic](https://en.wikipedia.org/wiki/The_Far_Side) that hits too close to home with this discussion...) you can now realistically threaten your neighbor.
**Our cold war would be down-right neighborly in comparison**
With the very first missle combined with a good map and the location of a military base on the dark side would instantly come [Mutually Assured Destruction](https://en.wikipedia.org/wiki/Mutual_assured_destruction). You'd likely have more missles bristling the dark side than the front simply because, no matter how good your neighbor's maps, you can't see them. Heck, if you fired you might not even know if you hit them. But that wouldn't stop a [Kubrickene military](https://en.wikipedia.org/wiki/Dr._Strangelove) from building every missle possible.
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> It would mean that nearly all scientific development, all military development, all important governmental actions, would migrate to the dark side. Planetary governments would be quickly subdued to control increasingly strategically important property. Natives of the dark side would quickly find themselves secondary to the fear of those from the front sides.
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**And that means satellites are all you care about**
Unfortunately, increasing tensions inevitably brings paranoia about how fast the enemy can attack. This would drive satellite technology to the extreme: and along with it, anti-satellite warefare. Initially and at all times, observation would be the highest desire: intel is king. But it wouldn't take someone long to realize if your neighbor can shoot down your satellite they can shoot down your missle. Transit time takes too long! So stealthy missle- or bomb-bearing satellites would become first-strike tools. Submarines might not be invented as more than a curiosity.
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> It's worth noting that the greater your fear of your planetary neighbor, the less you want issues on your own planet to take precedence. If you really feared the other guy, then "local" (on your own planet) suppresion would be brutal and quick, and that's assuming that everyone doesn't just fall in line because it's far easier to fear the unknown other planet than the unknown [Ted Bundy](https://en.wikipedia.org/wiki/Ted_Bundy) living next to you.
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A satellite cold war is inevitably what you'd have by 2050. Both worlds trying desparately to entirely cover the other world for observation, communication, and first-strike. Satellites would exist at varying orbits and employ stealth technologies wholly uneeded by planes on your own world.
If economic personal transportation between the worlds ever developed, it would probably be for the sake of embassies long before vacations. But, I don't see that happening in just 100 years starting with WWII. You'd see some amazing improvements, but even today it costs a boat load of money to put a handful of people into orbit... much less move them to the moon.
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> ...Or, possibly, everybody would be so enthusiastic about collaborating with their planetary neighbors that they would gather together in joy and happiness to share wisdom and ~~grass~~ chocolaty baked goods. But those movies never make money.
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Assuming the overriding need is defence then one of the poles would be a good location. This is because a pole would be energetically more difficult to reach than any equatorial site. Any missile launched would be hindered by the rotational speed of the body it launched from in achieving a polar orbit as a polar orbit is at 90 degrees to that of an equatorial orbit.
That’s not to say that an attack could not be made, it certainly could, but a greater mass of payload warhead could be launched at an equatorial site than a polar site.
This is why the US use Vandenberg AFB for polar launches instead of Cape Canaveral AFB and the Russians use Plesetsk rather than Baikonur. Vandenberg and Plesetsk are much further north so a lot less equatorial spin velocity needs to be removed.
The availability of land, productivity of land and the temperature would probably dictate where to locate cities unless defence was the overriding concern.
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In a world I am building, the days last 9 years. One of the results of this is that many species have evolved to sleep like dolphins, one half of their brain at a time. The two sides and thus two personalities never are conscious at the same time. Everybody is like this.
If such a system were to exist, how would these each personality keep track of what the other is doing while they are unconscious?
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In such a context, your species sounds more like two individuals that share a body in alternating times than one individual with dual personalities.
Of course, such distinction is arbitrarily defined by the chosen biology and planned society:
At one extreme, you will have two people that lead completely different lives in different times and may interact very little, like a flatmate or, in your case, a "bodymate".
Society-wise, law enforcement may play a role to prevent hostile interactions between the personalities, which would be seen the same way as attacking someone in their sleep.
Conversely, others may choose to share a lot and interact closely, like a sibling.
With that said, your gamut of relationships may be as wide as the one for two people in our reality.
However, of course, there is one huge caveat: they do share a body and, as opposed to flats, changing it may not be an option.
As such, I think most relationships will tend to be collaboratively and harmonious.
After all, if you assume that your species was subject to
some kind of evolution through natural selection, rivalling bodymates would probably not benefit from self competition and such characteristic would disappear.
If your species is human-like or have an analogous human-history, I think that would make for really interesting plots:
Surely, sharing bodies would have a huge impact in society and culture and would probably develop a whole set of social facts.
"Bodymates" would define a new kind of kinship, which may influence humanity more than siblings or parents do.
At the same time, it would also affect the other 'regular' kinship. After all, everybody would have two mothers, two fathers, etc.
Regarding communication, the time constraint would be pretty solid at pre-writing times.
Without distance (being it temporal or spatial) communication, both personalities would probably rely on biology tricks to communicate:
maybe the awaken personality could influence the sleeper's dreams, or hormones could be used to regulate mood, behavior and exchange information, in the same way that hormones work in our bloodstream to orchestrate body functions.
With the advent of writing, more complex and nuanced interactions could have developed:
Written communication would enable rich discussions and agreements, allowing 'bodymates' to become anything from acquaintances or business partners to close friends or platonic lovers who share an epistolary relationship.
With the onset of more advanced technologies, these relationships may indeed approach the level of generic relationships with other people. If the sleeping times of both personalities is roughly equal, written communication may somewhat be similar to what we have between parties in different time zones: huge communications delays between distant time zones is well understood and expected, and it doesn’t render communication impossible.
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If the process is really like sleep, I assume the brain does not "switch personality" suddenly, unless it is very tired. In real life we do not simply shut down and start sleeping randomly. We need schedules and (most of us) some time laying down quietly before we get to sleep.
This schedule means that in most cases a situation in which Personality 1 "wakes up" and discovers Personality 2 has taken him somewhere he doesn't know simply won't happen. It is as likely to happen as it is to you to wake up in an unknown parking lot without any idea of how you got there.
Your problem now changes from "waking up somewhere weird, not knowing what happened and/or is happening and having no idea of what to do" to simply "waking up on your bed just like any day and wondering what your body did during the night". Of course the idea that our bodies are strolling around without us is terrifying for you and me, but your creatures should be used to that.
Unless one of the personalities does something which might in some way endanger the body, I don't really see a need for the personalities to talk. Of course they can, if they want to, but there should be no need.
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Things get a little different when you start to think about interacting with other people. In most cases, you need to know whether you're talking to Personality 1 or 2. This will probably result in some sort of simple ritual before any real interaction starts. Simply saying your name before starting a conversation should be enough.
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The fact that everybody is sharing brains makes for great story potential and would make for a culture very different from what we're used to, but I don't see communication being a problem.
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Basically you're going to have to spend some time in catching up on what you already did today, whether that's in the form of reading a diary or a blog, maybe it's a one-on-one personality debrief, or someone else telling you about it. If you don't have that then you end up in a [Memento](https://en.wikipedia.org/wiki/Memento_(film)) situation, constantly waking up not knowing where you are or what's happening, that's actually workable if your two personalities live completely separate lives though. P1 wakes up eats, goes to work at the factory, comes home eats and goes to bed then P2 wakes up eats and goes to teach at the polytechnic comes home eats and goes to bed. P1 and P2 have similar skill sets, P2 teaches what P1 does for a day job, but completely separate lives lived on separate cycles that never overlap.
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Would this type of orbit be possible to achieve without external forces being applied? Is it possible at all? I have little to no background in the sciences so please explain like I'm stupid. Thanks!
[](https://i.stack.imgur.com/bCo1l.jpg)
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This is called the 3-body problem. You can find depicted a number of stable orbits. Here is one in 2d that I like.
from <http://sprott.physics.wisc.edu/chaos/3body.htm>
[](https://i.stack.imgur.com/kvhQD.gif)
There is a collection of 3-body orbits in this bizarre site. <http://three-body.ipb.ac.rs/>
The pictures are pretty
[](https://i.stack.imgur.com/haeIS.jpg)
but the text appears very, very slowly...
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That orbit is possible, if unstable (would need active correction from space station).
You would also be interested to [Low Energy Transfer Orbits](https://en.wikipedia.org/wiki/Low-energy_transfer) where you can plan a trip between several bodies (planets or, more easily moons) by switching orbit at certain exchange points.
These orbits are "slow" if compared with other solutions, including the classical [Hohmann Transfer Orbits](https://en.wikipedia.org/wiki/Hohmann_transfer_orbit), but require very low impulse, perhaps compatible with Space Station attitude engines.
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I remember reading [Tarzan](https://en.wikipedia.org/wiki/Tarzan) by Edgar Rice Burroughs. The protagonist is a an extremely strong man, capable of hand to paw combat with lions. The origin of his strength is attributed to living among gorillas all his young life.
What hand wavy arguments could I invoke for that incredible strength, speed and stamina of Tarzan, the ape-man? It doesn't look to me like any human being would win a wrestling match with a hungry lion, however hard they would train.
Tarzan is slightly more than 2 meters tall, he must have very strong bones and very efficient and powerful muscles. How did he get those, it's a mystery.
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Genetically is feasable.
[Louis Cyr](https://en.wikipedia.org/wiki/Louis_Cyr) was considered the strongest man ever lived. He was able to lift 500 punds with a finger and almost 2 tons with his back.
[](https://i.stack.imgur.com/iTjPL.jpg)
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A proper environment and training makes a lot of difference.
To give you a real life example that what looks like extreme performances can be routinely achieved, consider that in some african tribes a young boy, in order to be considered an adult man, had to be able, among others, to high jump his own height. That is having an elevation of 1.6 to 1.9 meters (while dunking NBA players reach 3.15 meters starting from around 2.0 meters or more).
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Tarzan is the effect of a great deal of hand-waving for reasons too copious to bother detailing them.
If memory assists, in the books he defeats bare-handed a gorilla (his step-father) by "re-inventing" a "double Elson" grip and thus breaking gorilla's neck.
The lion was defeated with another "re-invention": the lasso built with a rope obtained entwining grass straws.
While he was supposed to be very big, strong and trained from birth he was not supposed to be "superhuman" in any way.
Not having used our skills for *maaaaany* generations we have lost a lot of strength, skill and endurance [( I know this is a bad reference, but I'm lazy ;) )](http://www.smh.com.au/world/science/men-x2013-theyx2019re-just-not-what-they-used-to-be-20090805-ea31.html).
Just revive a Neanderthal or an ancient Australian and You'll have something "better than Tarzan" ;)
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The combination of a suppressed myostatin gene, adrenaline, and a lack of muscle inhibitors (in the brain) would make a person exceedingly strong. Perhaps too strong, as in hurting themselves strong. You could also give this person thicker bones to make up for that, but I'm not entirely sure what repercussions that would have. Swimming would certainly be more difficult, but it's also feasible that the extra muscle produced from the suppressed myostatin gene would make up for it.
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I'd be cautious about saying it's impossible.
There are plenty of reports out there of people winning fights against dangerous wild animals with their bare hands.
<http://mentalfloss.com/article/80239/time-carl-akeley-killed-leopard-his-bare-hands>, <http://www.cnn.com/2016/06/18/us/colorado-mountain-lion-attack/index.html>, <http://www.terradaily.com/reports/Ageing_Farmer_Kills_Leopard_With_Bare_Hands_In_Kenya.html>, etc.
Lions are strong but they're not invincible. I wouldn't be surprised if a skilled martial artist could beat a lion.
Personally, I'd use my bare hands to pull the trigger on my .357 magnum, but whatever.
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What is a plausible way for a planet to have time pass 10× faster than another? Seen the movie Interstellar? That one planet that time ran slower on? It the same idea but the other way around. Is there a way of making a planet's time (not rotation) move 10 times faster than Earth's?
So I am making an alien world where time travels 10 times faster than earth's. The people landed there 100 years ago earth time, but to them 1000 Earth years have past and several generations have been born. I know that if a planet is in a gravity well that time can move slower on a planet compared to someone not on said planet but can it work the other way too? What if the planet rotated really fast?
I'm not looking for a hard scientific answer since it is science fiction but I would like to make it somewhat believable.
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This concept is at the limits of speculative science. There two mechanisms that would have the effect of speeding-up time tenfold.
The first was proposed by physicist Robert Forward in that negative mass has the effect of speeding up time relative to everything that outside the region dominated by negative mass.
To quote myself from an earlier answer at [Speeding up time?](https://worldbuilding.stackexchange.com/questions/44963/speeding-up-time/45426#45426):
>
> Robert L Forward described a negative matter time machine thus:
> "Suppose we had a negative matter which is very dense. Time would run
> faster near or in the negative mass and we could make a hollow sphere
> of dense negative mass to speed up time." (in Robert L Forward, "Far
> Out Physics", *Analog*, August 1975, pages 161 and 163).
>
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> This doesn't speed up time in an unlimited way,the speed-up factor is
> only square of two faster. This is roughly only forty percent faster.
> Forward proves this from basic gravitation equations which look like
> they're adapted from equations about the mass of black holes (my
> guess!). Forward's article isn't detailed like a scientific paper,
> alas.
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The main drawback to this technique in speeding-up time on a planet is that the planet would have to be surrounded by a shell of ultradense negative matter. The other drawback is that time is only speeded-up a factor of forty percent (40%). This falls well short of tenfold faster.
In the same answer another mechanism for speeding-up time was proposed, based on the work of the physicist R T Jones.
>
> There is another way of creating speeded-up time. It involves special
> relativity and travelling at superluminal velocities. R T Jones
> published in the American Journal of Physics the possibility that
> travel faster than light results in time passing at the rate of the
> distance traversed. Basically for every light year a spacecraft
> travels one year passes shiptime.
>
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> So a FTL spacecraft only has to choose a suitable superluminal
> velocity to ensure enough speed-up time can pass. Since this is
> plausible science fiction, we can assume there is a chronology
> protection principle in this fictional universe to take care of any
> causality problems, Namely, there won't be any to worry about.
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This superluminal model isn't exactly what the OP had in mind. The planet would have to be moving at a constant velocity of ten times lightspeed (*c*) to achieve a tenfold rate of time passing.
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I'm not sure what you want is entirely possible (certainly not with Earth being one of the 'normal' planets) but how about this:
Time doesn't move any faster on the other planet, but to reach it you have to pass through the gravity well of a black hole (multiple black holes may be required to cover all approaches to the planet). During this journey time is slowed and what feels like a few moments is actually years, so when you reach the planet it appears to be moving through time at a faster rate. Similarly on the return journey you pass through the gravity well again and lose another few years so more time has passed when you return home.
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So a "Narnia" type situation?
This doesn't exactly answer but gives another way of looking at it which could help you: The travellers' brains and bodies have somehow sped up the reaction and aging process by a factor of 10 due to high concentrations of phlebotinium. Think of what's experienced by a fly.
Now there are still some factors to explain away - like any clocks or computers that they may have brought with them... Maybe they crashed landed and all chronometers were destroyed. There is other stuff like the length of a day and a year, etc. of course...
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In my story, it is possible (through alchemy, or some kind of mysterious magical process) to turn base metals into gold. This ability is not widespread, and knowledge of it is uncommon. In fact, most people and even most nations may be unaware of its existence. The Central Bank of a certain country has access to this ability, and uses it to maintain their country on the gold standard. However, they are aware of at least basic economic principles, and know that flooding the market with gold will quickly devalue it. What steps should this organisation take to ensure that their ability to cheaply generate gold continues to be useful? What risks would this generate, and what kind of cultures and/or institutions would need to be put in place to deal with those risks?
(Edit: For context, my idea is that the civilisation is placed roughly in the late 17-th early 18th century analogue. Reasonably advanced forms of government and warfare exist, but communication is fairly slow and analogue.)
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I should think this is not dissimilar to the real life situation of Norway (and a few others) with North Sea Oil. That is also a form of "free money", if you will; trillions of dollars worth of something they can get for relatively low mining costs.
Shouldn't your situation be similar? Have the government nationalize a large area of what is otherwise wasteland (say desert like New Mexico or Arizona), and "discover" gold there, a hundred feet down! But of course they just made a show of digging a great big hole, at the bottom of which they convert base metals into gold. They keep digging, but as a social service they hire the least intelligent citizens to work there, telling them the gold is in microscopic form and must be refined out, but every rock is chock full of it! That's why they only see rock and dirt. But they are making a good living and helping their country, they are heroes!
Your government can follow Norway's model: Their oil (your gold) is converted to cash; after paying their own citizens to work the oil rigs (your gold mine) the rest of the cash goes into a national fund; this fund invests the money in all sorts of ventures (tens of thousands of them). They earn about 10% to 15% on the money; and by Norwegian law, only the **profits** are allowed to be used to fund their government, their welfare programs, etc. The capital is never touched (well it can be diminished by failed ventures; but the Norwegian government is not allowed to use it or borrow against it for expenses).
Here is why that is important, and how it balances your gold production: Your gold will only ever fund legitimate business enterprises that have to gain a market in order to make a profit. Think of such business enterprises as more or less *inevitable.* People are going to invent things, or services, or whatever, and sell them, with or without your help. But (if your gold is not in the picture) the profits all these ventures earn get distributed widely, to many millions of investors. On **average** they all make that 10% to 15%. The market is never crashed by this profit making; all the profit comes from people that were willing to part with their money for whatever they bought; it is a legitimate creation of new value through human creativity and labor.
But with your gold **in the picture**, you are just outbidding thousands of those investors with an extra 5% or 10% to the entrepreneurs, and **you** take the profit those investors otherwise would have had. You just edge them into funding the riskier investments and taking more losses, and the entrepreneurs you are funding get a little extra equity or 10% more money to make their ideas work.
In business terms, you make the pie smaller so you can take a bigger piece of it: by giving the entrepreneurs a more generous deal you reduce the total amount of profit available to investors, but your little country is getting far more than its fair share.
This won't crash the economy, because your magic is really just diverting profits that **would have been earned anyway** into your pocket instead of the pockets of other investors. It is just a **redistribution** of the profits.
Your cost is the sham of pretending what you are mining is 20% gold, when you are crushing worthless rock and turning scrap iron into gold. But of course you have insanely high security around the mine, inside the mine, and where the transmutation actually occurs: Only the wizards in the hardhats are ever allowed to empty the final centrifuges and crucibles of the "final product".
Or something like that; I am sure there must be ways to mix pure transmuted gold into the crushed rock so you can "burn off" the rock and "purify" the residue into tons of gold, so to outside observers it has all the appearance of a real operating mine.
By analogy, suppose Norway had discovered a magical way of converting sea water into crude oil, and decided to *pretend* they were drilling for it, to the point of actually drilling holes and arranging for transmuted sea water to look like it was coming up from those holes. I'm not sure we'd know (or care) what was *really* happening half a mile beneath the North Sea.
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Basically you have a money that are worthless in their own now, having any worth only because people believe it. And your central bank can print, wait, transmute more on a whim but people trust it not to. Congratulations, your people basically introduced [fiat money](https://en.m.wikipedia.org/wiki/Fiat_money), not by decoupling existing money from gold backing, but by turning the very gold to something without value. Doesn't matter, it's all the same.
1. Your central bank has power of central bank against other countries that still use gold.
2. You can introduce and regulate inflation, to prevent hoarding, to make sure your economy wouldn't be coin-thirsty etc
3. If you are slow enough for other countries to keep using gold, inflation in your country will mean that their goods will be getting cheaper. Good for import, bad for export.
4. Being too open about that prematurely, or being greedy, will make other countries turn to other metals for coins, and may end up with hyperinflation.
Responsibility of institutions able to print money is a complicated matter, a field of study too broad to fully describe, so keep in mind that's exactly what you did, and keep above points in mind.
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It has actually happened; and, sadly, it didn't work.
There are three fundamental problems with the premise: first, *nobody* in the late 17th century had any idea of *"basic economic principles"* — Adam Smith's seminal *[Wealth of Nations](https://en.wikipedia.org/wiki/The_Wealth_of_Nations)* was published in 1776, that is, in the second half of the 18th century; second, gold was always too expensive to be used in everyday transactions — at all times and in all places the metal in actual circulation was silver; and third, money is just a lubricant, not a fuel: it makes economic transactions easier, it accelerates exchanges, but it does not, in itself, produce national wealth.
(That's to avoid the obvious observation that in the late 17th or early 18th century there was no such thing as a central bank. There wasn't even the faintest idea of a central bank. What would a central bank even *do* in the 17th century?)
Leaving aside the mechanism proposed in the question, there actually was a powerful nation which, at one time, found a means to produce unlimited amounts of precious metals: that was Spain, which in the 15th and 16th century conquered a huge empire in the New World and gained access to gold and silver deposits beyond all imagination. *[The Spanish Treasure Fleets](http://rads.stackoverflow.com/amzn/click/1561642614)* (link goes to Amazon) brought so much gold and silver into Europe that "[prices rose sixfold over 150 years](https://en.wikipedia.org/wiki/Inflation)" (Wikipedia), generating the [price revolution](https://en.wikipedia.org/wiki/Price_revolution) which was one of the most important factors in the final demise of the medieval world.
Because the value of one monetary unit is not given by some mysterious intrinsic property of the material of which it is made; the value of one monetary unit is simply the value of the goods and services available for sale divided by the number of monetary units in circulation. A small and steady increase in the number of available monetary units *may* be conducive to a stable economic growth, provided the economy has the capacity to increase productivity to match. Today, central banks routinely [target an inflation rate](https://en.wikipedia.org/wiki/Inflation_targeting) of about 2 or 2½ per cent per year, which is adequate for a modern reasonably developed economy; but in the 17th or 18th century economies were must less sophisticated than today. (And while modern central banks can easily provide limitless amounts of money, no transmutation needed, they still miss their inflation target at least as often as they hit it.)
So basically what the fortunate king or prince or emperor can do is to put a small amount of the newly found metal in circulation, not as a gift, but as a price paid for actual goods and services — essentially start a public works program. (This is the fundamental principle of the [Keynesian](https://en.wikipedia.org/wiki/Keynesian_economics) recipe for bootstrapping an economy out of a recession.) They should take care that prices don't run away, and they should try to avoid using the new metal to pay for unessential imports. (Spain did not heed this advice, and used her immense treasure to pay for everything and anything, thus destroying her own competitivity and eventually losing her empire and her power.) Once the economy grows sufficiently, expand the public works program a little bit, but never overdo it lest the artisans and the farmers and the bankers and the industrialists become addicted to state contracts.
Using monetary policy is tricky, and there is still no sure-fire guaranteed recipe. That a 17th century ruler could get it right is possible, but bordering on the miraculous: that is, a great subject for an engaging story.
[Answer]
1. Make just enough gold as is necessary for a healthy, growing economy, and
2. make up a reasonable cover story as to where it's getting it. (EDIT: for example, plant the gold in a "rich, but narrow vein", and then make sure that the "miners" are loyal, and not too plentiful.)
] |
[Question]
[
If a typical human were shrunk down to be 3cm tall weighing 2.5 grams (ignoring all problems that would cause), would the blade of the grasslike plant described below be able to stop its fall from 6 inches up?
The grass has a rough texture as shown below
[](https://i.stack.imgur.com/3F0Xi.jpg)
([image source](http://www.micronaut.ch/blades-of-steel/))
The blade of grass is at a 70 degree angle and measures 2 ft long and 1 ft wide curling in on the sides (so he doesn't slide off) and comes to a point on the end. He lands half way down.
Would it be possible for him to come to a complete stop before touching the ground?
[Answer]
Take a hundred foot mine shaft, drop mouse down it and the mouse will land uninjured. A person sufferong a similar drop will break every bone in his body. An elephant will splash.
The smaller an animal gets the less a fall can hurt it. Terminal velocity for small things is just too slow. Assuming the humans muscles don't shatter his miniscule bones during normal movement a fall is not going to bother him at all, so he doesn't *need* the grass. Buts lets say he wants to use it anyway.
Grass is a pretty wide description as well, some grasses would stop him no problem other would not, just make it wider and more rigid if you don't think it will work. Something like zebra grass would work no problem.
[Answer]
## No
70 degrees is a really steep angle. If your tiny man was conscious, there's a chance he could grab onto some protrusions and slow himself down. Unconscious, though, there's simply not enough to keep him *on* the leaf.
After 6 inches, he'll be moving at [about 1.73 m/s](https://www.angio.net/personal/climb/speed.html). I second @JasonC's experimental suggestion just to make sure, but that's fast enough I would expect him to hit the leaf, begin sliding down as the leaf bends under his weight, then the leaf springs back and throws him off.
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[Question]
[
I'm excited to share my little *secret* with you, if you promise me not to tell anyone *else* and help me with my little, ambitious quest.
I think I managed to found a way for someone to enter the internet. Literally.
Okay, you may be laughing now, but just let me introduce **the principle** behind this as simple as possible:
Our brainwaves are actually just interactions of nerve cells, so by replicating the interactions between devices in the internet, we can upload one's consciousness to the internet.
First we upload the consciousness into these processors (shows a 30x30x30 cm computer). This will serve as our initial interface to the internet. Then through the processors (note: he keeps saying "processors", instead of "computer") you can upload your consciousness to the internet by having many devices replicating the packets back and forth.
Now you see? It's the best invention **ever!** No! You cannot try it! It's for me! There will be no one smarter than me, ever! It's best for humankind to upload myself and let my genius mind be the eternal guide to humanity!
Yeah, whatever. I know you will call me that... hmm? Interesting [post](https://worldbuilding.stackexchange.com/questions/31388/how-would-facebook-sysadmins-prevent-the-summoning-of-cthulhu). I didn't know it's so easy to eliminate me after I become immortal. This is *very inconvenient*...
---
I know this is not the most original story you've ever heard, but
**how to prepare for digital immortalization through uploading your consciousness to the internet, to ensure that you can't be removed from the internet?**
Some obstacles I've thought:
* Firewall and other security system, including antivirus
* Power, and internet connection, as stated in the link
The consciousness will live on the internet, and is capable to take over a device (similar to virus/hacked device - hence I fear antivirus and such). The process will mostly be slow at first, but as soon as more devices have "downloaded" the consciousness, the process will be faster.
This takes place on this Earth and now. I'd handwave the exact process of the "uploading" for now, and assume that the consciousness is able to learn and breach through every possible firewall or software-based protection, given enough time (remember the processing power gets higher the more devices taken over, similar to [Plague Inc.](http://www.ndemiccreations.com/en/22-plague-inc)).
Taking over a device is not necessarily leaving a file(s) behind, but by [backdooring](https://en.wikipedia.org/wiki/Backdoor_(computing)), you save time when you want to use the device.
**Bonus:** if someone can figure out how to eliminate this consciousness **after he's taken over all devices in the world**.
[Answer]
Upload the consciousness to every peer-to-peer file sharing service you can find, especially the anonymous ones.
Peer-to-peer file systems (any distributed file system, to be honest) should replicate the data they store onto multiple servers to ensure data is always available and, if one server is lost, destroyed, or corrupted, the data is recoverable. P2P systems, however, store this data on the users' machines, and not necessarily all of the data is found on one node in the network.
In other words, users will be intentionally adding their system to the growing consciousness without ever realizing it. Anonymous systems go even further, concealing the data being stored on any given node in the network: you don't know which files are on your system, only that they are consuming X amount of space.
Once your files are on a system, all you have to do is mine the list of IP addresses in the user's cache and copy yourself to those. Rinse and repeat. Eventually, you'll hit something with a lot of traffic, like Amazon.com, and then you have access to the IP address of every user who doesn't surf the Internet anonymously.
**How To Defeat**
1. Print the contents of Wikipedia.
2. Build a new Internet based on a different protocol and never connect
it to the infected one.
3. Never distribute a patch to existing systems to use the new
protocol. Never build a new system with access to the infected Internet.
4. Never distribute a patch that allows an existing system to
communicate with a new system. Never build a new system that can
communicate with an existing system.
5. Shutdown all data centers and network hubs serving the infected
Internet and burn them.
6. Start over.
7. Create a new Wikipedia using the printout.
[Answer]
Ok, first let's ignore the memory size required to copy ones mind. So if full transfer 1:1 would require, for example, 30 TB it should be able to"zip" its core to 15 KB and then "unzip" and crawl to get the knowledge back.
Second problem is to forfeit the assumption that there is a central part responsible for certain tasks (like Broca's area ). Those 15 KB can be stored in every 100 MB (of the 1:1 data) and its only default setting would be "check if the previous link respond". If not then unzip and start rebuilding lost data. So you can cut off 29,9 TB of consciousness and it will still try to relocate, multiply the core and again size lost data (or just try to grow again not caring what is lost).
How to fight it? Same we do with the virus. You separate the core part on a device that is solitary and then try to implement the autodestruct part (that's why you should not set "automodify" to yourself as you can accidentally invent suicide code).
So not try to build antivirus but more like cancer. So you would absorb the code that on one hand grow with you, leaving the data slightly changed enough to be "burned earth" for you but usable after your demise to others.
Other way would be to overload you. Give you so much information that would require from you to shut some outputs and ports cornering you in some DEEP Blue instance that can be just switched off.
[Answer]
Another obstacle/threat would be other digital consciousnesses. Your genius may think he's the first but there could have been others before him, maybe a pilot before he deemed the process "safe" for his use. You didn't mention what happens to the "original" but the digital copy would become its own entity and should evolve as it spreads. Isolating a copy of that consciousness and allowing it to develop independently could create a new distinct consciousness. Manipulating the new copy could be possible to introduce a directive to eliminate other consciousnesses and would effectively create an AI antivirus. The psychology of the genius could be played on to do this. He thinks he's the best so pitting one version against another isn't inconceivable.
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[Question]
[
>
> It has been a really long trip since we left our home planet. We have seen so many stellar systems but no planet was over 5 on our Viabilometer©... I was desperate until today ! My Viabilometer© is blinking ! We found one ! A planet with a score of 19.583 !
>
>
>
I am trying to establish a "planet viability scale" which can give a score (say from 0 to 20) reflecting the chances of a planet to be suitable for life. More precisely the potential of evolution of a life-form if I drop a microorganism on the planet.
For example :
* A planet with a score of 1/20 allows only days of survival for the microorganisms, thus they would not evolve a lot.
* A planet with a score of 10/20 allows some microorganisms to survive long enough to allows sub-aquatic vegetable and animal life-forms, but they would never go on earth and thus their evolution is limited.
* Finally, a planet with a score of 18/20 allows microorganisms to develop well and "quickly" enough to be able to escape their home planet and travel through stars.
In order to build this scale, I need some criteria that help evolution or curb it. **What are the planet criteria that influence evolution of life ?**
I know that distance from star, the type of star, presence and composition of the atmosphere, temperature are capital for example. Are there any others ? In what extent are they important ?
[Answer]
H. Lammer in *What makes a planet habitable? (2009)* proposed the following classification system for water dependent life bearing planets.
* **Class I** habitats are planetary bodies on which stellar and geophysical conditions allow liquid water to be available at the
surface, along with sunlight, so that complex multicellular organisms
may originate.
* **Class II** habitats include bodies which initially enjoy Earth-like conditions, but do not keep their ability to sustain liquid water on
their surface due to stellar or geophysical conditions. Mars, and
possibly Venus are examples of this class where complex life forms
may not develop.
* **Class III** habitats are planetary bodies where liquid water oceans exist below the surface, where they can interact directly with a
silicate-rich core. Such a situation can be expected on water-rich
planets located too far from their star to allow surface liquid
water, but on which subsurface water is in liquid form because of the
geothermal heat. Two examples of such an environment are Europa and
Enceladus. In such worlds, not only is light not available as an
energy source, but the organic material brought by meteorites
(thought to have been necessary to start life in some scenarios) may
not easily reach the liquid water. If a planet can only harbor life
below its surface, the biosphere would not likely modify the whole
planetary environment in an observable way, thus, detecting its
presence on an exoplanet would be extremely difficult.
* **Class IV** habitats have liquid water layers between two ice layers, or liquids above ice. If the water layer is thick enough,
water at its base will be in solid phase (ice polymorphs) because of
the high pressure. Ganymede and Callisto are likely examples of this
class. Their oceans are thought to be enclosed between thick ice
layers. In such conditions, the emergence of even simple life forms
may be very difficult because the necessary ingredients for life will
likely be completely diluted.
According to him any of those could bring forth life. Just each higher class makes it more likely. You could make those in 1/20, 5/20, 10/20 and 15/20. Gives you a baseline to work with.
What you haven't listed explicitely but could be covered by type of star is radiation. The type and amount of radiation that hits the surface. Now you say wouldn't the atmosphere cover that? Not neccesarily. Jovian moons can be protected by the magnetic field of their host. Kilometers of ice too can block enough radiation.
Beyond liquid water not really anything seems required. Radiation would probably be the second thing to get that greatly increases the odds of life. Gamma bursts can whipe a planet clean. Impacts the size of what created the Moon really screw with life too.
So a third requirement could be a quiet galacted neighborhood. Beyond that anything is icing on the cake. They'll help but aren't required.
Magnetic field that protects the atmosphere against solar flares stripping it away? That's nice for your higher life forms. But under the surface smaller life might still develop regardless.
So in summary
1. Liquid water, either by being in the habitable zone or energy by the
pressure of gravitational pull of nearby bodies. For example moons
of Jupiter.
2. Radiation protection, magnetic fields, layers of ice. Something to
shield our organisms from deadly radiation.
3. Quiet neighborhood, speaking of radiation. Even if regular radiation
won't kill you a galactic disaster could strip your planet clean.
4. Magnetic field, to retain an atmosphere long term.
[Answer]
There are five dominant factors that determine a planet's habitability. These are discussed in greater detail in [this made-for-worldbuilding table](http://www.lpi.usra.edu/education/explore/our_place/hab_ref_table.pdf).
**Temperature** influences how quickly atoms and molecules move. Too high of temperature and they won't stick together. Too low, and they won't come together in the first place.
**Water** is a universal solvent and an agent of transportation for chemicals. It is a necessity for life as we know it.
**Atmosphere** gives life shelter against harmful radiation and helps regulate surface temperature, as well as supplying necessary chemicals to air-breathing lifeforms.
**Energy** is the basis of life. Every organism needs energy to perform life functions, whether that comes from light or chemical sources.
**Nutrients** are what build and enable the growth of organisms. Without nutrients, life cannot develop.
[Answer]
Since other replies are addressing the planet criteria, I'll address the scale itself. A number from 1 to 20 can only measure one parameter, or rather I can only convey one concept with this scale: Viability.
Sequential numbers imply there are steady increments of viability along this scale. If terraforming were possible, you'd have to go through each sequential state.
If the conditions are not sequential but each state is more or less unique, you'd use letters of the alphabet. They would probably correspond to the order in which they were discovered and codified.
But I suggest you consider a compound number system that can convey more than one parameter. For example **J7** would not be the seventh J, rather it conveys two separate concepts represented by a letter and a number.
For inspiration: the web uses hexadecimal numbers to describe colors. The first 2 digits are the color red, the next 2 are the color green, etc. After you learn the system you can estimate how bright and the general hue by comparing the 1st, 3rd, and 5th digits. Also interestingly the numbers count from 0 to 9, then from A to E. Throwing in Greek letters helped Star Trek sound esoteric (or possibly math/academic). So consider a compound number system where the digits are represented by various counting systems.
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[Question]
[
**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
Our universe is described as having three physical dimensions, plus one time dimension, where the eigenvalues for the physical dimensions are all the same, but the eigenvalue for time is opposite (x, y, z, t: +, +, +, -) or (x, y, z, t: -, -, -, +)
A universe where the eigenvalue of time is equal to that of the spatial dimensions (x, y, z, t: +, +, +, +) has been explored in depth by Greg Egan in his [Orthogonal](http://www.gregegan.net/ORTHOGONAL/ORTHOGONAL.html) series of books.
However, what would happen if the eigenvalues of the physical dimensions were *not* identical, e.g.: (x, y, z, t: +, +, -, -)? or even, in a 4-physical-dimensional universe, (w, x, y, z, t: -, +, +, +, -)?
In the universe I'm interested in, there is one time dimension with a negative eigenvalue, and 3 or 4 physical dimensions, but *one of the physical dimensions has an eigenvalue equivalent to that of the time dimension*, while the others have the opposite eigenvalue as is the case in our universe.
How would the physics and chemistry of such a universe be different to our own? How would movement in the negative-eigenvalue spatial dimension work? Would life - or even matter - be able to exist?
[Answer]
In the special relativity, the 4-distance is calculated on this way: $ds^2=dx^2+dy^2+dz^2-dt^2$.
In your world, having a space-like dimension with $-1$ signature, it would be calculated like $ds^2=dx^2+dy^2-dz^2-dt^2$.
It has far consequences:
1. The space won't be [isotropic](https://en.wikipedia.org/wiki/Isotropy) any more. Thus, things would behave differently if you rotate them around the $z$-axis and any linear combination of $x$ and $y$. The laws of the physics would behave differently in the different (space) directions.
2. On the [Noether theorem](https://en.wikipedia.org/wiki/Noether's_theorem), the symmetries of the Universe have a deep connection to its conservation laws. The isotropy of the space results the conservation of [angular momentum](https://en.wikipedia.org/wiki/Angular_momentum). In a non-isotropic Universe, the angular momentum isn't a conserved quantity any more.
3. Any effect will be instant around any direction, for which $dx^2+dy^2-dz^2=0$. It would effectively mean, that moving any point-like particle on such an axis, you get the same system. This would be a new symmetry, which would result a *new conservation law*, what doesn't exist in our Universe.
4. To calculate, which conservation law is it, is complex but it doesn't require much more math/physics skills as in the high school. Any physics student from around the second year of his studies can do this for you, although it probably wouldn't be easy to find a cooperative one.
Having an additional, conventional space dimension (thus, an 5D spacetime) doesn't change this significantly.
I am not sure, but this "new conservation law" would probably essentially mean, that any point of the space, for which $dx^2+dy^2-dz^2=0$ are the same. If it is correct, then the result is that this negative-signature space dimension "eats" all of the others. Thus, you have essentially an 1D space.
Note: this all depends on if the (non-curved) spacetime of your Universe is still governed by the Special Relativity, as ours.
---
Extension: things would significantly change if you calculate what happens with the gravitation, too. Gravitation changes the geometry of the spacetime, thus the distances wouldn't be calculated like $ds^2=dx^2+dy^2-dz^2-dt^2$, instead you have a tensor (essentially a table) for which
$$ds^2=\underline{dr} \begin{bmatrix}
g\_{xx} & g\_{xy} & g\_{xz} & g\_{xt} \\
g\_{yx} & g\_{yy} & g\_{yz} & g\_{yt} \\
g\_{zx} & g\_{zy} & g\_{zz} & g\_{zt} \\
g\_{tx} & g\_{ty} & g\_{tz} & g\_{tt}
\end{bmatrix} \underline{dr}$$
$g\_{n\_1 n\_2}$ is determined by the mass and impulse distributions, it is essentially the General Relativity analogy of the gravitational field. For small (much lighter as black holes) and slow (much slower as speed of light) you get the Newtonian gravitation from it.
It is possible, that near strongly graviting objects the spacetime would be multidimensional again.
[Answer]
**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
There is no difference betwee time and space dimensions, it s just a shortcut of language we use to describe t in our universe.
Greg egans calls z u. It doesn t matter if you say z/u is a space or time dimension, what matters are the implcation for the space time geometry.
So yes, Dichronauts describes your universe.
So our universe is (+,+,+,-). Greg Egan's Orthogonal describes (+,+,+,+) and Dichronauts describes (+,+,-,-). I guess all the possibilites have been explored!
How about 5 dimensional universes Mr Egan ?
] |
[Question]
[
Suppose a group of intelligent but insane people has developed mind control technology. They have managed to plant a chip inside the US president's head. They can wirelessly send signals to his mind and he will obey them without question. The president is as rational as before, and perform his day-to-day tasks as before. When he receives an instruction, his own counter-reasoning shuts off and he obeys the commands. He is still rational in understanding the commands, also behaves rationally, making it almost impossible for a common man to notice. However a series of tests by a psychologist will probably reveal the mind control. So will an operation on his brain.
If the group wants to eliminate as much of the human race as they can (even including themselves), what would be the best strategy\* to do so? Would it be to just ask the president to try bombing the whole world with nukes\*\*? Or will it be a more planned and subtle approach that makes use of the other powers of the president?
\*Best may be hard to determine, so any good strategies are welcome.
\*\*Using nuclear weapons requires [approval of a second person](https://skeptics.stackexchange.com/q/34644/33071), so it will take some planning even to get access to the nukes.
[Answer]
No. Your chipped president works intelligently. If he gets his command, he probably won't shout on the spot to his aide, "nuke Iran, Russia, Europe, Israel, Japan, China and every NOW".
Instead, first he would slowly change the people in the command chain to ones who don't question his orders even in such a case. It wouldn't be hard, because most people obviously does this.
Second, he would create such a world political atmosphere, where attacking everybody wouldn't be a hilarious decision. It may take years. It probably requires the analysis of intelligence documents, how every nuclear power would behave in the case of a nuclear attack.
Furthermore, the Humanity *has* the capability to wipe out its race from the Earth, but he didn't develop the technology for that until now. It is mainly because no nuclear power has such an intention. They want to win over the others, but not the humanity (including themselfes). Even if all of the nukes would be detonated, they (+ nuclear winter + long term radiation + infrastructural damage) would only wipe only the majority of the humanity. Some people in deep bunkers would survive.
There are atomic bombs tuned for long-term radiation - in plans. They would be ordinary fusion/fission bombs, but with a cobalt coating. The neutron radiation of the explosion would irradiate this to such a cobalt isotope, which is strongly radioactive, and decays enough slowly that even the few people living in bunkers won't have enough time to wait the end of the radiation. To our best knowledge, no such bomb was ever built. Exploding enough from them could exterminate the humanity.
[Answer]
## TLDR: Either quick, spontaneous nuke before anyone suspects or enough propoganda to get the country behind you and then nuke.
There will be two methods our insane group will see:
* Hit hard and fast before anyone has the chance to intervene.
* Slow and subtle so no one notices.
Because the real obstacle is that, according to the [25th amendment](http://constitution.laws.com/american-history/constitution/constitutional-amendments/25th-amendment) if the president's cabinet have reason for concern that he is unfit for office they can transfer his power to the vice-president (though congress must also agree). If they make the president do anything drastic but can be stopped it is likely the cabinet will try to stop him.
So we need a balance.
**Spontaneous Nuke:**
* A Nuke attack must be [discussed with an aide and be verified by the secretary of defense](https://en.wikipedia.org/wiki/Nuclear_football#Operation), however the secretary of defense has no power to VETO the order (he is only there to verify that it is, in fact, the president sending the order) and the aide, whilst there to advise on the method of attack can be fired and the president could hire anyone he wants as his aide - anyone who will agree with him.
+ This Nuke launch would, therefore, be a viable option unless any of the officers along the way who must verify a launch were to object (though it is illegal for them to do so and will be given no reasons, only the coordinates and codes for their attack. As such it is likely at least one of the nukes will be fired.
+ After a nuke is fired at another nuclear capable country - most likely Russian - and make sure not to disable any of their own nuke sites. Firing on moscow would be most effective in forcing retaliation. I'm unsure as to whether any of the other countries would join in though, they have been given no reason for an attack.
So nukes could cause pretty devastating effects. The [US and Russia have by far the most](https://en.wikipedia.org/wiki/List_of_states_with_nuclear_weapons#Statistics_and_force_configuration) and [between them they have enough to wipe out all life](http://gizmodo.com/5899569/how-many-nukes-would-it-take-to-blow-up-the-entire-planet). But you need them to fire them all without anyone intervening, without **a sensible person saying "Hang on, we don't want the world to end."**
Now we move on to the second choice.
**Slow and subtle:**
* Propaganda, provocation and espionage. Probably working between US and Russia again (because those nukes are still our best bet) but we want everyone involved to really think that launching those nukes is the best bet.
* We want the president himself to believe attacks are what is best (when he isn't under effects of mind control).
+ [The US is no stranger to propaganda](https://en.wikipedia.org/wiki/Propaganda_in_the_United_States) and it is likely the president has some input. You want to increase the dislike for Russia, reduce trade with them, increase the cost of flights there etc.
+ Increase the checks on Russian nationals visiting the US to make them feel they are singled out.
+ Perform US military exercises in places near to sensitive Russian sites. The Russians will see this and, suspecting a move, prepare their own propoganda and increase tensions.
+ Launch some small scale attacks within Russian through planted spies and leak enough information to Russia to have them catch your spies but not after they blow up part of a military base or some other sensitive area.
Once tensions are high you need to organise a fake attack on the US and claim it was Russians. Then you can start a war and, eventually, use nukes. The problem here is you need to rely on getting it done in four years or getting re-elected.
Or, you could just get rid of any pollution bans, increase your use of fossil fuels and give global warming the boost it needs to be irreversible.
[Answer]
You could have a 2 stage plan for the slightly more patient. Biologicals followed by Nukes. Start with the man in charge launch a covert biological weapon strike in the middle east, preferably as near as you could get to Pakistan and India both. Perhaps another in a Muslim majority nation as close to China and maybe even Russia if at all possible. This is because the current geopolitical bad guys are ISIS, so you could get a little bit of plausibility. This starts the massive death thing going.
Next Propose a plan that the only way to curb the plague is to use thermonuclear weapons. Cauterize the wound, so to speak. At around the same time as this rhetoric starts, leak to Pakistan, China, Russia, and India, that the US President is nuts and has territorial ambitions in those same areas. He also started the plague. Give it a few hours for maximum freak out, but not really enough time for cooler heads to take over. Just as the rhetoric reaches a fever pitch, Launch.
The whole Mutually Assured Destruction thing should start kicking in at this point. India and Pakistan will hit each other, destroying that part of Asia. The entire Middle East gets reduced to glass. Russia, China, and the US render the remainder of the planet almost completely uninhabitable. You get left with part of Africa and maybe South America more or less untouched, but they won't last long as the side effects of destroying the northern hemisphere wreak havoc on weather patterns, depositing radioactive fallout, and so on, take their toll.
To be more certain of the Southern Hemisphere, just make sure the plague gets released in Johannesburg and Santiago the day before the exchange. A bunch of people huddling together in shelters should make for major petri dish conditions.
[Answer]
Does the president actually have to do it? If not:
Control the president.
Now is the time of Space! Kennedy only went to the Moon, we are going to the asteroids! It's time for space mining!
Launch a mission to grab a 10 mile diameter iron asteroid and bring it back to Earth's orbit with an Orion drive.
This part of the project operates aboveboard, the only tampering is that some of the black hats are deeply involved in the project. However, they are acting in the interest of success, spotting them will be extremely difficult.
The dirty deed is taking over the guidance programming. Rather than a high capture orbit (you don't want to be using an Orion too close to Earth if you can help it) it's on an impact trajectory.
Use **all** the bombs, including those meant for the capture. It's heading for Earth on this orbit, intercepting it is going to be very difficult.
While this might not get a total kill it will end us as a technological species.
[Answer]
Certainly, even without the extra details it's easy to say without reading that he could.
Given that the most powerful man on the planet has access to nuclear weapons, and that the US has enough nuclear weapons to end the world as we know it, I would very much say that it is entirely possible to end the human race. Maybe not directly, but, say, you nuke North Korea; Now North Korea is going to send out nukes to wherever they can, and you'd essentially start a third world war.
Another option would be to start a third world war without nuclear weapons- You seemed to put an emphasis on nuclear warfare as an implication. Have the president declare war on the rest of the world, this gives you an excuse to use the nuclear weapons. Now that the entire planet is against you, it wouldn't seem illogical to fire all the nukes you've got. We had enough nuclear power to eradicate humanity during the cold war, I don't imagine we went backwards at any point over the years.
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They would probably crack open one of the secret virus weapons from a covert lab. Much easier for crazy leaders to push the button on such a weapon, than try to retarget and launch thousands of nukes without being stopped by someone sane, or some sanity check safety systems. Although the president has their finger on the launch codes/button, there is still a looong chain of command and computer systems required to actually carry out launches.
A viral weapon only needs a handful of people to go out to subway stations, shopping malls and airports.
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None of the nuclear or viral options would end the human race. Kill a lot of people, sure, but there'd be survivors who'd eventually rebuild. No, what you have to do is accelerate the burning of coal & other fossil fuels, to the point where you cause a replay of the Permian-Triassic Extinction.
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Is it the case that if I was to develop an alien world that the most likely outcome would be that the animal in the middle of the food chain is going to be the one that is most likely to develop intelligence?
Edit: Are there reasons why a low level animal would gain intelligence? What about higher predators?
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"Middle" is a pretty broad term when it comes to a food chain. Here on earth it would describe anything between modern humans and plankton. So most likely the answer is yes... But that's not fun, so let's look a little deeper.
Most species that are commonly recognized as intelligent are social, most are carnivorous or omnivorous and most are mammals. Notice that I said "most" quite a few times there. There are a few notable exceptions like the cephalopods, which aren't mammals or particularly sociable.
Brains are hungry things which require a lot of calories, in most environments that means eating your fellow creatures, at least occasionally.
Bigger brains usually need time to grow, develop, and train which means that mammals get a bit of an advantage due to lactation and hence attention/protection from a parent.
Which brings us to the social component. Animals the have bigger brains often have longer adolescent periods, which means that they aren't fully self sufficient, thus they need protection, food, and so on. Animals that can rear young cooperatively get a significant advantage because they can leave the crumb-snatchers with the neighbors while they hunt and forage.
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It's not uncommon to see "higher level" predators gain some higher intelligence. See dolphins, wolves (pack hunters in general)
It's also not uncommon to see "lower level" omnivores gain some higher intelligence. See raccoons, monkeys
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As for the notable exceptions... We're still not sure why cephalopods have evolved to be as apparently intelligent as they are. Some seem to think it may be due to sexual selection, female cuttlefish seem more likely to select males that are smart enough to disguise themselves to sneak by the larger stronger males.
So... If you're working on intelligence in an alien world, just make it sexy and things should progress pretty well...
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Regarding your question about animals lower down the food-chain developing intelligence, I want to present you [Alex](https://en.wikipedia.org/wiki/Alex_(parrot)). Although Grey Parrots sometimes eat insects, they are generally frugivorous - eating fruits, seeds and the like. Still they show remarkably intelligence, matching the level of apes in cognitive tests.
The following reasons are brought forward to explain their intelligence:
* living in variable environments
* highly social
* huge forebrains
* extended developmental period and extended life span
This list is based on this paper: [Cognitive ornithology: the evolution of avian intelligence](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626540/) and can be used to explain the development of animal intelligence in general.
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It reminds me of [the old Douglas Adams joke about dolphins](http://www.goodreads.com/quotes/811-for-instance-on-the-planet-earth-man-had-always-assumed).
Let's define "intelligence" as an improved mental capacity that has given a species an evolutionary advantage – it must effect the birth / survival rate of the species or it doesn't play a role in their evolution.
By that standard some of the things we consider a hallmark of higher intelligence (philosophy, rocket ships) aren't actually contributing to population growth, but medicine and microbiology have lead to child-immunization causing the population to boom and society to diversify. This creates opportunity for genetic evolution in all directions, not just intelligence (consider poor eyesight, deafness, allergies, and other genetic "defects" that are no longer severe handicaps thanks to technology).
But the impact of technology is not always straightforward. Genocide and war kill millions but presumably there are winners whose genetics supplant the losers. And counter-intuitively, birth control leads to healthier children who live longer, and stronger cohesive families due to mothers surviving childbirth and helping to raise their own grandchildren. It's not always about quantity. In both these cases it's about the allocation of resources to fewer survivors.
We use to believe that intelligence meant the use of tools and advanced engineering, but now we've observed so many animals creating tools and building complex structures it hardly seems special anymore. We are starting to recognize animal intelligence in more subtle ways, like their [understanding of physics](https://www.youtube.com/watch?v=9Db6JZHh0SA), [language skills](http://www.usatoday.com/story/news/nation/2013/11/24/smart-dog-border-collie-learns-language-grammar/3691967/), [social fairness](https://www.youtube.com/watch?v=meiU6TxysCg), and [the ability to empathize with what others are experiencing](http://www.telegraph.co.uk/news/science/science-news/12117501/Animals-more-capable-of-empathy-than-previously-thought-study-finds.html). Any of these might have a daily impact on survival.
Some types of intelligence we recognize in the animal kingdom (that aren't top predators) include:
* [an elephant matriarch's memory of geospatial locations](https://www.eurekalert.org/pub_releases/2008-08/wcs-sfe081108.php).
* [a crow's ability to solve mechanical problems](https://www.youtube.com/watch?v=ZerUbHmuY04).
* Beavers don't just build dams as a shelter, they [re-engineer the environment to create a refrigerated larder](http://www.animalplanet.com/tv-shows/other/videos/fooled-by-nature-beaver-dams/), which impacts numerous other species.
So to get back to your question, any mid-foodchain creature that is using its wits, memories, or social skills to avoid being eaten, store food, and raise healthier children can be considered to have evolved intelligence.
As to the last question about top-predators, the same rules apply. Some predators benefit from social intelligence and co-operative child rearing, and even use [co-operative physics](https://www.youtube.com/watch?v=VyfOp_keW0A) to hunt, but other top-predators are loners who hide their vulnerable babies while hunting and hope for the best. Some top-predators are their own worst enemies, for example [lions where the females live co-operatively but the males are responsible for most infant mortality, and this article](http://www.brighthub.com/environment/science-environmental/articles/60010.aspx) talks about the fallacy of confusing the survival instincts of the individual with the survival of the species.
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I think that "mid-food chain" is the lowest you can probably go. For one thing, it takes time and learning for intelligence to aid survival. It takes time for the previous generation to pass the survival knowledge on to the younger generation.
I don't think that low-food chain animals would live long enough to be able to do that. In fact, the lower in the food chain you go, the more creatures seem to be adapted toward: mature quickly and breed lots. They tend to use hardwired instincts to bypass the learning curve that more intelligent creatures use.
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So in the story I'm writing, mankind has advanced farther in the next few decades than we have over the past couple thousand years. Colonization has allowed us to settle the planets, and the FTL drive has opened up the ability to reach the stars. But for in-system travel, it wasn't until recently that we began to embrace a fuel source that was both powerful and efficient enough to get a ship across the solar system in a matter of days: **metallic hydrogen**.
Although this resource was nearly impossible to create in the early 21st century, engineers and scientists realized that it could remain **meta stable** outside a high pressure environment. And with probes confirming large deposits of it on Jupiter and Saturn, a rush formed to mine this nearly limitless resource from the planets' lower atmospheres (much like the oil boom during the industrial revolution).
So, if we managed to synthesize meta-materials capable of withstanding the extreme pressure and weather of Jupiter and Saturn, what would be the best method to set up a series of mines that are capable of tapping into the layers of metallic hydrogen far below these planets' clouds?
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**First up some pre-ramble**
* You can have a solid and liquid form of metallic hydrogen. It is, however, all still just hydrogen at different pressures.
* [This paper](https://arxiv.org/ftp/arxiv/papers/1610/1610.01634.pdf) has a pretty good introduction to dealing with/forming metallic hydrogen in the lab (could be interesting for further points in your story.
* The graph below (from the paper above) shows your transitions. The basis of your question (I suppose) is how to get the hydrogen out and keep it in the same phase in the diagram.
[](https://i.stack.imgur.com/98qIG.png)
+ So we need about 500Gpa of pressure to have our hydrogen solid metallic with low temperatures.
* My thinking here is that the solid takes up less room and low temperatures and high pressures, perhaps, are easier to maintain in a space ship where you might lose power.
**So, what do you need?**
Firstly a point about the hydrogen (which my method will hinge around), whilst you want it in its metallic form in the end it doesn't have to always be this way. I've only been able to find [evidence](https://science.nasa.gov/science-news/science-at-nasa/2011/09aug_juno3/) of liquid metallic hydrogen.
Basically my idea comes down to **putting a pipe\* down into the metallic hydrogen and changing its phase** in one of two ways:
* **Lower pressure pipe**: Your pipe is at a lower pressure on the inside and at the bottom lets the hydrogen in, where the liquid hydrogen will become gaseous and travel up your pipe more easily.
* **Lower temperature in the pipe**: Your pipe could be cooled at the bottom, making the liquid hydrogen drop out into its gaseous state and, again, be more easily pumped out.
For the same reasons I stated above I think the pressure is a better method.
The crux of it is that what you're going to do is make your hydrogen non-metallic to get it out, then repressurise it again once it reaches your platform.
*\*Very long pipe*
Another point is about the pipe, platform and them being subjected to incredibly high winds. Your pipe would need to be very strong but flexible (most likely in sections that have flexible connectors). These could connect up to platforms which shouldn't, I don't think, be orbital (I imagine the pipe being connected to an orbital platform would drag too much on the pipe and break it more often) better to have some sort of blimp that you can collect the hydrogen from periodically.
**Edit: Just to point out that it is possible (but not experimentally proven) that the hydrogen could be meta-stable in it's metallic state. See Mike's comment or the end (~page 8 of the paper I added). This would mean you don't have to necessarily keep at as high a pressure once it has been formed. This doesn't stop the method of extraction working since liquids with the option of different pressures will still travel towards the lower. It is, however, an interesting point that could be used in your story. At the moment we don't know so you choose how it is in your world.**
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Your actual mine would be entirely robotic. There's absolutely no point even thinking about sending manned vehicles that deep. So it would consist of robots under AI control mining the metallic hydrogen and dumping it into containers. You'd need to make sure that their hulls were very well insulated, too, to survive the powerful electrical currents that must be running around Jupiter's interior to generate that magnetic field.
The containers are the fun part; how do we get them back up? The best option is likely to be by using effectively hot-air balloons. Create a large envelope and heat the liquid metallic hydrogen inside. The balloon can then ascend through the oceans and cloud layers above. As it ascends and the pressure changes, the balloon would have to be constantly heated and modified to remain less dense than the ocean/atmosphere around it.
You probably couldn't get all the way to the upper cloud layers with a balloon - they're already made of hydrogen, after all, so the balloon would lose a lot of its lifting power - but it should get the load high enough to be hooked by a recovery vessel.
Of course, the other option is even more fun - pick a gas giant, and get rid of the atmosphere. Blow away the hydrogen and helium envelope to expose the core, and mine it directly. But if you have the tech to do that, you can probably make your own damn metallic hydrogen.
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You can attempt to use the chimney principle, turning the pressure differential at your advantage.
Place a convergent pipe near the core, provide an heat source to warm up the hydrogen and let it float up into the chimney. Wait at the other end of the chimney and harvest what gets out of there.
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Modern education teaches citizens that the point of an individual in society is to contribute labor. In a world with limited natural resources, we use this idea to measure an individual's worth in society and award them resources (via money) proportional to the amount and value of their work.
However, in the next N years, (100, 500, 1000, whatever you believe) computers will likely come to outperform humans in all disciplines (manual, intellectual, creative, administrative, and all others). Let us postulate, though, that this level of artificial intelligence arrives before we find a way to access virtual unlimited stores of natural resources.
**In this theoretical world, what will be the value of an individual in society that we use to distribute these limited natural resources?**
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*Note*: My question is similar to [this](https://worldbuilding.stackexchange.com/questions/45749/what-happens-to-a-worlds-working-population-between-the-phases-of-manual-labor) one, but it differs in a few key ways: Firstly, there is a section which specifically references "a few thousand engineers, scientists, and world leaders" still being necessary to run society. I am asking about a situation where there are between 0 and 50 of these people. If there *are* any humans holding these positions, it's only to make the populace less scared of a robot revolution.
I am also asking about specifically the situation with respect to limited resources, whereas that question talks about a timeline of the transition.
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They could contribute labor which derives value from being human labor, as explained in [this answer](https://worldbuilding.stackexchange.com/questions/16807/can-humans-interact-meaningfully-with-the-economy-when-robots-are-better-at-ever/16819#16819) to a slightly different question. Consider how many people in the real world are willing to pay more for a [fair trade](https://en.wikipedia.org/wiki/Fair_trade) product, even if it is not better in itself than an unfair product.
Or they do *not* contribute enough to pay for their upkeep. Perhaps they are lucky enough to own assets which pay their [rent](https://en.wikipedia.org/wiki/Rent-seeking). Consider who owns real estate right now -- humans, not computers. If enough humans are far-sighted, they'll keep the title and only rent it to the computers.
Last but not least, all humans might become welfare recipients. Even if they have make-do work, it doesn't pay their living. Let's hope the computers are more humane than the humans.
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**Warning: I provide a series of ideas below, yet I can see how none of them work.** This leads me to consider that humans would be taking the place of lesser animals compared to the AI.
If the robots find us interesting we could be pets. Otherwise they could exterminate us or exile us. Our hope may be in AI thinking that we are not that different.
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Evidently the first thing that can be contributed is **resources**, yet we are moving past that because in the given scenario those are considered limited.
The next thing people can contribute is **productivity**, **labor** is a shorthand for that. If we consider that two persons contribute the same if they produce the same, regardless of who made more effort to do it, you are rewarding *productivity* instead of *labor*.
Note: I don't know what the government is, yet I'll go on the assumption that it can be corrupted (even if it is AI).
*I'll be using umbrella terms, stretching the concepts a bit when we can conceive scenarios where they converge.*
Ok, now we move past that... we have:
* **Time and Attention**: You can exchange your money to get things faster (for example by buying something pre-made instead of buying the materials, or by using the transport system instead of walking) you can also expend your time to get things (that is how you pay for many *free* websites... they make you expend time looking at advertisements). Consider also that finance can be understood as converting time into money, and that in a world where the banking system everything can do micro-transactions you could pay for exactly the time you use a service (eg: how many seconds you watch TV). In this scenario you could be paid "time" by doing work or by watching ads, you use it to access services, and you could even invest your "time" via the banking system. So, time and money converge into a single concept (that we could call "credits"). See [In Time (2011)](https://en.wikipedia.org/wiki/In_Time) and [Time-based currency](https://en.wikipedia.org/wiki/Time-based_currency). *Note: attention of computers and robots could be considered worthless. Also AI may not be prone to propinquity repetition. Yet, there may no longer be a need to advertise to humans at all.*
* **Information** (Access to): Each person is a source of information as data point in statistics. For market research or scientific studies, people with special condition could be more valuable. Now, the next step after sharing your information is to serve in experiments... and evidently it is expected that this would be paid. There are other sources of information such as solving math problems for prizes, or even cryptocurrency. And you may earn money by creating new algorithms to process interesting data, or by doing scientific research. *Note: there maybe scientific breakthroughs about the human body or otherwise that are beyond AI (depending the laws of your universe and how much scientific knowledge goes into creating AI to start with).*
There are other things individuals contribute that are not necessarily paid. Don't think what people may do for their society, but how they can break them... then whatever it is they can do to prevent that is of value. Here are some ideas:
* **News and Narrative** (as accounts of real events): "Misinformation" an "propaganda" may lead to people going against the system. So, we infer there is value in having people somewhat informed. In fact, people consume narratives. They may be used for entertainment, also it is usually the narrative (or should I say "history"?) around unique items what gives them value (an example of this is "Made by humans", but will the AI buy this?). Fame ties well to this concept, as people appreciate more the narratives of the famous, and people become famous because of their narrative. *Note: perhaps computers are better at creating new fictional tales, yet what actually happens to people is what actually happens to people. In particular if there is a speck of unpredictability in humans. Although AI fiction could be supernormal stimulus, and people may prefer that. After all, the goverment can use misinformation and propaganda for their own benefit.*
* **Emotional and psychological support**: Desperate people do desperate things! Consider that people have social behavior, and belonging to a group can be rewarding. This means that providing psychological support to others (or you could say, "being their friends") can be considered a service, and thus something people contribute to society... well, what society is it if there are not relationships? *Note: Love, belonging and esteem may not be fully replaced by robots as long as we think of them as "other", and even if that is archived there could be value in the old ways.*
* **Security**: For people not destroying all the things, we need security. In our world guards sell security for money; you may also buy security in the form of protection systems. Those could be either informatic protections (antivirus, firewalls, intruder detection systems, etc...) or physic (fences, locks, security cameras, crazy drones, etc...). We usually consider security to defending from robbery, espionage, and damage. The idea of defending against damage could be extended to include maintenance as a form of security. We can extend that further to consider maintenance to people (a.k.a. health care). All those are services people contribute to society. *Note: As long as humans are taking the initiatives this would be an arms race. I agree that at some point AI could make it not worthy for humans.*
Here are other things we could use as proxy for **productivity** or **labor** (these are proxies of labor, so they may not be interesting in your universe):
* **Karma**: The government may pay people based on what is considered "good behavior" (according to the government). In this scenario following the rules means money and breaking the law means less money. This may also be extended to different campaigns, for example: have compost in your backyard, help the sick, provide shelter for the homeless, join the military, lose weight, using approved products, etc...
* **Health, Comfort and Well-being**: A job deteriorates your health; you are paid more if you are healthy. That is using health as proxy for effort, and effort as a proxy for labor.
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Well, there are short-term and long-term answers to this. In the short run, there are some jobs that even the type of AI you're describing would have a hard time doing (or at least, doing better than humans to the point where human work is no longer needed). Examples of this are novelist (or really any kind of artist), motivational speaker, prostitute, entrepreneur, etc. Also, as has been mentioned, some humans may prefer human-made products to machine-made ones.
In the longer run, we will eventually reach the point where AI is so good at writing novels that Game of Thrones will read like a 6 year-old wrote it. Once we reach that point, humans really have nothing of value they can contribute to society outside of basic human needs like giving emotional support, having children, or just generally enjoying themselves (excising, playing video games, reading, etc). Personal enjoyment is very much of value to "society", because all societal value should, in the end, transfer into human utility. As for rewarding some humans more than others, those that own property might be able to hold onto it for some time and charge rents, but in the long run we'll basically be a bunch of very wealthy and lazy Communists. Keep in mind that while resources may not be "infinite", AI this powerful would inevitably be able to generate far more resource productivity than humans currently do, so most folks wouldn't see their standards of living go down at all (if they did, they would have an incentive to go out and work to bring them back up, which violates the premise of the question).
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Resource allocation will be different and based on the value their intended use has on society and as a proportional welfare e.g. a space craft, or food resources etc. It's also dependent on whether or not people want to continue to capitalize on supply and demand of resources in the future e.g. if scarcity disappeared, nobody would even desire to attempt to capitalize, however, I think in the future resources will be allocated proportionately and rationally/ appropriately, due to their supply on earth, not our ability to purchase them.
Humans will give themselves purpose by continuously achieving their worthy ideal; probably exploring gaps in knowledge, through adhering to the scientific method of inquiry...
That is what humans should contribute to; either on a personal level through exploration of less complex hypothesese or through efforts at the frontiers of all humankinds knowledge.
Who knows, all we can do is say if an outcome is sensible to predict and i'd say based on my limited knowledge on the nature of humankind that everything everyone is writing on here is sensible..
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First off, to be clear, the "modern education" you speak of is "capitalism," specifically "neoliberal capitalism;" I mention this only because other socioeconomic structures are more than possible given the conditions you're asking about (some form of "hi-tech feudalism" perhaps.)
To your question: I would suggest that "Very Hard AI" (replicating the processing "types" in a human brain as opposed to sheer digital processing power, which I can readily imagine) will probably never come to be, because
any and all efforts to model (let alone replicate) the human mind are laughable:
1. Whether it's a toy airplane or a macroeconomic simulation, a "model"
is a set of internally coherent suppositions about some aspect of
reality - and, as nobody knows what the human mind actually is, what
is being modeled?
2. Computers are digital (binary - or, with quantum
computing, "trinary") whereas the human mind is singularly "analog."
Given that last, there are 100 billion neurons in the human brain, each with the possibility of having up to 40 connections per neuron. Given that a few molecules present or absent in synapse can result in a change in state-condition, one would have to not only calculate how to simulate 100,000,000,000^40 analog connections of widely disparate nature, but, as the level of "granularity" required to translate analog-to-digital is unknown, this might theoretically need to be done to a level of granularity equal to the Planck limit.
I mention all this in an attempt to better frame the question ...
... SO, if there is any value to be found in passing digital data into a brain and having the brain be able to output digital data in turn, I can readily imagine an interface between brain and machine wherein digital data is passed back-and-forth to ask and answer problems of an immense degree of complexity -
In short, a person could rent out their mental power/processing capabilities either "standalone" or as part of a much more complex system.
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Let me pitch you a setting: The year is 2017, and thanks to an extradimensional portal Humans have begun to develop superpowers. The Power Scale for these supers is low-to-mid Street Level
(meaning that a Superman-esque superhuman would cause EVERYONE to flip).
Note: The source of the Superhumans power comes from a variety of Nodes scattered across their body/in their cells [Similar to the Magic System from this question: [Would "magic" still be called "magic" in a modern era?](https://worldbuilding.stackexchange.com/questions/67918/would-magic-still-be-called-magic-in-a-modern-era) (except the fact that their Nodes can only channel their energy in a specific manner)].
So my question is... How could I introduce these Superhumans into my setting (which is IDENTICAL to our world... except for the superhumans) without causing the collapse of society.
Bonus if you can come with a good name for them!
Note: The advent of Superpowered Humans is not immediate, rather it occurs over a few generations (with an increasing number of them per generation)
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If twenty-five percent of the world's population developed super-powers, then everybody will know someone who has super-powers. Often that will be someone in your family. It's hard to panic if Aunt Hortense can levitate or light the gas stove with her finger tip.
While there maybe people who can bend steel bars with their bare hands, there were be few who can transport skyscrapers or change the course of mighty rivers. (And if I read the OP's question correctly, that means none.)
There are a couple of aspects of this transformation to the global population. These supers are beginning to develop their super-powers. Aunt Hortense might start by hovering a centimetre or two off the ground, gradually she will rise higher, and perhaps eventually she might sail up to tree tops.
The supers will need to learn how to use super-powers. Strong enough to lift a car? OK. That's about a ton. So someone who can lift a ton will need to learn how to lift cars carefully, without wrecking them.
As for flying, never does anyone explain how super who can fly can do so without flying lessons. Flying an aircraft is extremely non-intuitive. Ask anyone has to fly an aircraft. Fortunately, the level of flight supers are likely to have means they get stuck in orbit or achieve escape velocity to never return. Perhaps they can only fly at one hundred metres maximum and at about running speed. or if they're lucky as fast as a fast car.
Since their super-powers have a form of biological basis, those super-powers will need to be powered and fueled by metabolic energy. They have to eat. Not all their super-powers will enable the supers to just take what they want. Soon they will slow down or run out of power, then face the consequences of their super-powered misdeeds.
Zapping your kid sister and the dog with your electrocyte-based electricity manipulation may have been fun at the time. But when your battery's flat and a pair of angry parents descend on you, it might be time to rethink junior supervillainy as a career option.
The chances are this will become a world where people, at least, a quarter of them, will be able to do remarkable things. This won't change their lives too drastically. Very few will don a mask, become a vigilante and go crime fighting. The usual suspects will use their new found super-powers to assist with their criminal activities. But the boys and girls in blue will have their fair share of super-powers too.
There will be a distinct absence of supers who can achieve world domination overnight. In some ways it will be like if 25% of the population became instant Olympic athletes. Amazing at first, amusing later on, and eventually situation normal before next Xmas.
The next generation of kids will soon be asking: how did people cope without super-powers? And they will the usual answer of we just did because that's how things were back then.
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Some suspension of disbelief will be required no matter what solution you'll find, but I assume you're looking to minimize the need of it as much as possible (The reader will only need to believe that the solution worked, instead of believing that society wasn't destabilized).
So! Let's break the problem down. How would you make normal people NOT freak out when faced with an unexpected, life-changing situation?
For that I have to ask- what do people do when faced with such situations? Usually- they look up. Be it a deity, the authorities, a mentor or a parent, or even themselves, if they have the qualities required.
So, how do you use this answer to prevent mass-panic? Question is- who exactly will be doing the "calm down the public before Molotov start flying" song and dance? The government? A mass-media channel?
To put it on track- if people can hear the message "everything is fine' all around them, and from sources they can trust- they're gonna buy it. Think about celebrities lighting cigarettes with their fingertips on twitter like nothing's out of the ordinary, youtubers and internet personalities flooding the internet with "everything is ok", so much that it becomes a meme. (I really like this one btw, imagine a picture of a silly dog or something and it has the text writing "I woke up to find my nose on the floor, but everything is OK")
Someone has to pull the strings, and it's not gonna be an easy task, not for him to do, nor for you to describe, but I'm sure just that would be a fascinating few chapters to read!
That or, you know, just have the whole world dream the same dream or something...
Oh, and you wanted a name for them, right?
I vote for "the lucky ones". Would probably catch quickly by everyone, and could even make for a few wordplays here and there.
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First, I'll go for the bonus round.
Names for them:
Specials
Extras
Exceptionals
Beyonders (as in beyond human)
Phenoms (short for Phenomenals)
Marvels
the Powered
the Endowed or an endow
Remarkables
the Inspired
the Unfettered (as in unfettered by human DNA)
Gifted
Slur names for them:
Freaks
Monsters
Deviants
GenDevs (Genetic Deviants)
anomalies (can be an insult or not)
**Really have to say that there's a lot that people won't believe this is happening for quite a while.** There will be YouTube Videos, but there are plenty of crazy You Tube vids that are faked.
In the meantime, there will be high level government or corporate orgs that might notice this, and want to study these folks, while at the same time **keeping it a secret for as long as they can, so that they can experiment for as long as they can. They will also recruit specials to work for them, and tag/track any they can clandestinely.**
As long as they don't glow or anything, these folks tend to be just a little more than ordinary people. That's not to hard to cover up, up to a point.
Eventually there will be stories here and there in fringe news--and buzz feed, and other sources, and finally it will make mainstream, in a newspaper. Then, there will be a TV interview. There might be a hero that is known. **It's best if the person who is first known is something like a firefighter or police officer, whose abilities will be shown in the line of duty. If there's a PR firm or something estimating when it will break, they might specifically break it this way, for minimum panic.**
] |
[Question]
[
These people inhabit an underwater city.
In the city there are pools that connect the dry habitat with the outside ocean, this of course mean that the habitat is unpressurized and therefore the internal atmospheric pressure is the same as the pressure at the bottom of the sea.
So my question is: how deep can the city be?
I do not care what they breath as long as the air mix can let them live as deep as possible without any major problem. I also know that they cannot simply go back to the surface; to do that they need to undergo decompression, but that's ok, they are supposed to live there!
[Answer]
The change in pressure below the ocean is approximately
$$\frac{dp}{dz}=\frac{1\text{ atm}}{10\text{ m}}$$
where $z$ is measured from the surface of the water downwards. We also have to add in the one atmosphere of pressure from the atmosphere, meaning that the pressure is really
$$p(z)=1+\frac{1}{10}z$$
where $p$ is in atmospheres. According to [Wikipedia](https://en.wikipedia.org/wiki/Deep_diving), 100 meters under the surface leads to pressures dangerous to even the most experienced divers. We know that $p(100)=11\text{ atm}$, where [nitrogen narcosis](https://en.wikipedia.org/wiki/Nitrogen_narcosis) becomes extremely hazardous, and could lead to death. A much better depth, in terms of narcosis, is about 40 meters, where $p(40)=5\text{ atm}$.
That said, there's no reason for your city to have the same pressure as the outside ocean. It should absolutely be pressurized, with the correct mix of gases. Pure oxygen can lead to [oxygen toxicity](https://en.wikipedia.org/wiki/Oxygen_toxicity).
[Answer]
A lot depends on the air mix - very deep diving can involve helium instead of the usual gases, as the **partial pressure** of oxygen and other gases becomes critical. As this is a technical area, the best answer would depend on the gas mixture and the community's needs. These three wiki articles should help a lot with background and resources:
<https://en.wikipedia.org/wiki/Breathing_gas>
(Gaseous mixtures used for various depths and circumstances)
<https://en.wikipedia.org/wiki/Deep_diving>
(Overview of breathing requirements and gas mixtures in the context of water depth, and how different depths are generally seen)
This of course excludes any acclimatisation/adaptations that may occur, or (in the medium term) evolutionary changes, which may well occur too.
<https://en.wikipedia.org/wiki/High-altitude_adaptation_in_humans>
(May spark ideas by looking at how human biology has adapted in the communities that live permanently in the opposite environment)
] |
[Question]
[
**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
A [Kardashev Type III](https://en.wikipedia.org/wiki/Kardashev_scale#Type.C2.A0III_civilization_methods) civilisation has need of a long-scale timepiece, and as such has arranged a series of planets around a black hole such that their orbital periods can be used to tell the time in the same way an analogue clock would be on Earth (don't worry about how they know where 12 o' clock is).
However there is an issue: This clock is meant to last a long time (on the order of tens of billions of years), and the orbits of the planets must remain *precisely* calibrated to their original orbital periods. Another slight wrinkle is that this race plans to leave the universe (long story. Blame a space wizard) for a little while and so won't be able to actively modify any of the orbits while they're away. A drift of 1 part in 1014 (the same as the [TAI](https://en.wikipedia.org/wiki/International_Atomic_Time)) is permissible.
Given that this civilisation is capable of carting around black holes and planets (potentially to an extragalactic location if needed), is this 'orbital clock' possible? If not, what is the maximum accuracy one could hope to achieve (given that there are multiple planets in this clock)?
*Please note:* The hard science tag really matters here. Equations to prove yes or no are a must.
[Answer]
Your main problem is that the planets will comprise a [chaotic system](https://en.wikipedia.org/wiki/Chaos_theory). This is why the [stability of the Solar System](https://en.wikipedia.org/wiki/Stability_of_the_Solar_System) is so difficult (possibly impossible) to determine. Our best models are valid for perhaps $\sim10^8$ years - at *best* (see [Laskar et al. (2004)](http://adsabs.harvard.edu/abs/2004A&A...428..261L)). This is the [Lyapunov time](https://en.wikipedia.org/wiki/Lyapunov_time), over which orbits are definitely chaotic (the 50 million years quoted there is an extreme lower estimate). Determining that requires calculating the system's [Lyapunov exponent](https://en.wikipedia.org/wiki/Lyapunov_exponent), which is not easy and which I will not do here. The two are related, though, by the equation
$$|\delta Z(t)|=e^{\lambda t}|\delta Z\_0|$$
for Lyapunov exponent $\lambda$, time $t$, and separation $Z(t)$.
If we assume that this system has a similar Lyapunov exponent, then over even $\sim10^9$ years, the system is chaotic, and the clock becomes essentially useless.
---
Another issue that makes the idea of a central clock - or an extragalactic clock - a bit of a pain in general is time dilation.
Some postulates:
1. Being a Type III civilization, these beings have control of the entire galaxy and likely inhabit it. They therefore need the clock to work in all parts of it.
2. The galaxy has a non-uniform density, and therefore a non-uniform potential. Even treating it as a large disk and neglecting *individual* effects of bodies, there will be [gravitational time dilation](https://en.wikipedia.org/wiki/Gravitational_time_dilation).
3. The civilization will survive for a long period of time, and therefore any discrepancies must be tiny; otherwise, the effects will snowball.
I'll take the calculations from [John Rennie's answer here](https://physics.stackexchange.com/a/161482/56299). If we assume a central potential of $\Phi(r=0)=6.4\times10^{11}\text{ J kg}^{-1}$, and time dilation of the form
$$\Delta t\_0=\Delta t\_{\infty}\sqrt{1-\frac{2\Delta\Phi}{c^2}},\quad\Delta t\_{\infty}\approx\Delta t\_{\text{edge}}$$
where $\Delta t\_{\text{edge}}$ is a time interval at the edge of the galaxy, then we find that
$$\Delta t\_{\text{edge}}-\Delta t\_0\sim7\times10^{-7}\Delta t\_{\text{edge}}$$
That causes a discrepancy much greater than one part in $10^{14}$ - not from inaccuracies in the clock, but just because time will tick differently at different points in the galaxy. This clock cannot be used throughout the galaxy - or even in a small portion of it. It would be much better to use different clocks in different regions. And if you put it *outside* the galaxy, you can't even use it in the majority of galactic locations.
Yes, you could make corrections depending where you are in the galaxy, but the equation given above - and in the linked answer - is only an approximation. It takes some more complicated computations to correctly figure out gravitational time dilation in the galaxy to enough precision, and frankly, there's a point at which it's just not worth it.
[Answer]
Edit: This answer plays around with one extreme of the question with a large orbital radius and a large orbital velocity that immediately self-destructs. It probably misuses special and general relativity. Also, it requires a civilization with energies at it's disposal beyond the Kardashev scale. Please take it with a grain of salt. It is a thought experiment gong wrong. (Though even negative thought experiment results are still results.)
Let's suppose you give the planet a large orbital radius R. As R approaches infinity the effects of the black hole approach zero. What you're left with is a planet moving through the vacuum of space. Now the question becomes "how consistently can a planet moving linearly through space be used as a clock". Nobody knows how many meteors are moving through the void between galaxies so let's get back to it later. Now the only things that can change the velocity of the planet are radioactive decay from the planet's surface, fluctuations in radiation pressure from the stars coming from the night sky of space, quantum tunneling, and unpredictable variations caused in the gravitational warping of space time. Most of these effects are extraordinarily tiny.
Radioactive decay from the planet's surface can be lowered to below humanity's ability to measure by using non-reactive substances. Quantum mechanics becomes unmeasurable once you hit macroscopic scales, on planet-sized scales it is completely irrelevant. Radiation pressure is stronger than both of these and the random pressure from solid objects hitting our planet even if it's just cosmic dust is greater than radiation pressure because an individual dust particle imparts much more momentum than an individual photon. The momentum of a cosmic dust particle is about 10km/s \* 10^-4kg = 10kg m/s. The momentum of the greatest cosmic ray ever measured has an energy of 3 x 10^20 eV. Divide this by the speed of light and we get momentum of 1.6x10^-7kg m/s, a difference of eight orders of magnitude. The effects of cosmic dust are smaller than the effects of cosmic meteors. How many cosmic meteors are out there? Nobody knows.
But the cosmic dust and cosmic rays don't really matter because you can minimize their effects by speeding the planet up to near-lightspeed. The faster you get the planet going the less small changes in momentum are going to affect it's velocity, thanks to relativity. (Though you do eventually end up producing a nuclear explosion with energies far beyond known physics. At this point you have a bomb, not a clock, and what you're measuring is the shockwave of weirdness.) So if you get a planet moving at 99.999...% the speed of light you can make the clock arbitrarily precise, except for variations in it's course caused by unpredictable gravitational fluctuations warping spacetime. These come from dark matter and dark energy, stuff we also don't understand.
So the answer to your question is that by bending the rules of this situation beyond the breaking point we can make the clock arbitrarily precise (at least up to the Plank limit beyond which time and distance cease to mean anything). The precise accuracy of the clock for a given set of circumstances is far beyond known physics.
But what if we didn't stretch the rules to the breaking point and instead used a simple situation that we understand very well? What if we took an Earth-like planet and placed it around a sun-like star with similar Earth-like conditions? Then the orbit would vary about as much as Earth's does.
## Edit: Neighboring Galaxies
Joe asked if the orbital radius would be large enough to be affected by neighboring galaxies. I didn't think of that in my original answer. The answer is yes, so it looks like we'll need a Kardashev Type IV civilization to push around some galaxies to give this clock some space.
First. Let's calculate the orbital radius. We'll start with GMm/R^2=F=mv^2/R. (I'm not sure if this equation doesn't work for scales this large. In fact, I'm not even really sure what'll happen to orbits at relativistic speeds.) This equation reduces to GM/v^2=R. The mass of the black hole in the center of our galaxy is 8.2×10^36 kg. Let's plug this into the equation and use the speed of light as v. This gets us R=5x10^21m. The third-closest galaxy to the Milky Way is 1.6x10^21m so this orbital radius on the order of the distance between galaxies in our neighborhood.
However, the distance between galaxies varies and we're not in the most empty part of the universe. Cosmic voids contain few to no galaxies and have a diameter or 10 to 100 megaparsecs. R = 5x10^21 meters = 0.2 Megaparsecs (Mpc). So you could fix the lightspeed orbital clock in one of these with a 5 Mpc radius to spare. This means the neighboring galaxies may be 20 times farther away thereby exerting at least a 400th of the gravitational force of the black hole at the center of this clock. That is significant.
Technically what we need to worry about here isn't gravity from neighboring galaxies but rather gravity from dark matter which there is more of and that will produce a stronger force. We don't know how the gravitational pull of dark matter fluctuates because we can only measure it's long-term effects on large scales that places dark matter beyond the realm of current science, so let's just focus on the matter galaxies for the moment.
They will certainly throw the clock off significantly if the civilization building this clock but will they do so unpredictibly over tens of billions of years? The universe is only 14 billion years old. I doubt we can predict galactic movements that far out, but you'll have to ask a Kardashev Type physicist to be sure.
[Answer]
The OP requested a hard science answer for a question that essentially doesn't need or effectively never needed a hard science answer.
Why? Because the black hole clock as proposed is an absurdity. Also, it is completely unnecessary. This answer shall not attempt demonstrate why a back hole clock is an absurdity. Many of the other answers demonstrate the problems involved. There is a currently existing technological that will perform the necessary timekeeping for a Kardashev III civilization.
The ideal timekeeper for a galactic civilization is a pulsar clock.
>
> A pulsar clock is a clock which depends on counting radio pulses emitted by pulsars.
>
>
>
In fact, the pulsar clock already exists and is operating in Europe.
>
> The first pulsar clock in the world was installed in St Catherine's
> Church, Gdańsk, Poland, in 2011.[1](https://en.wikipedia.org/wiki/Pulsar_clock) It was the first clock to count
> the time using a signal source outside the Earth. The pulsar clock
> consists of a radiotelescope with 16 antennas, which receive signals
> from six designated pulsars. Digital processing of the pulsar signals
> is done by an FPGA device.
>
>
>
A K3 civilization should be to adapt the same principles and perform timekeeping to orders of magnitude of accuracy better than currently achieved. Exactly what any self-respecting galactic civilization needs to achieve.
Once the rotational frequency of any given of pulsars is known, it will be possible to determine the time anywhere in the galaxy.
>
> In the nearly inertial frame of the Solar-system barycenter, the
> rotational period of a pulsar is nearly constant, so the
> time-dependent phase (t) of a pulsar can be approximated by a Taylor
> expansion
>
>
>
> ```
> (t)=0+f(t−t0)+21f(t−t0)2+
>
> ```
>
> where 0 and t0 are arbitrary reference phases and times for each
> pulsar. The important thing about pulsar timing, though, is that the
> observed rotational phase difference between each of the TOAs must
> contain an integer number of
> rotations. Since each TOA corresponds to a different time t, the
> parameters that we are fitting for, such as f and f, must result in a
> phase change between each pair of TOAs i and j that is an integer
> number of turns, or ij=n turns (1 turn = 2 radians). Since all
> measurements are made with regard to the integrated pulse phase rather
> than the instantaneous pulse period, the precision with which
> astronomers can make long-term timing measurements can be quite
> extraordinary.
>
>
>
Extraordinary long-term timing measurements, isn't that exactly what a K3 civilization will want for its time keeping? No need to shunt black holes and their planets around. The proposed interstellar clock using black holes is a non-issue. The real answer is they wouldn't bother to even think of doing it -- except as an amusing hypothetical exercise -- because pulsar clocks do work, will work, and likely to do so into the far future.
Sources:
The Wikipedia entry for [pulsar clock](https://en.wikipedia.org/wiki/Pulsar_clock)
Pulsar Timing at <http://www.cv.nrao.edu/course/astr534/PulsarTiming.html>
] |
[Question]
[
Short version - some physicists have created a pathway that appears to permit near-instantaneous travel between two distant points. Objects propelled through one side on the correct vector will emerge on the other side immediately. After initial tests with inert objects and recorders, scientists decide to send some life forms through - a mixture of bacteria, plants, and small animals.
**When studying the effects on these life forms, what would biologists be looking for?** I'd assume things like cancers, infections, and general well-being, but is there anything more specific? How many generations would they want to study to generally agree that travel through the Pathway appears to be safe?
Edited to add:
The specific thing I'm working on (and I realise this is getting close to making it story-specific rather than worldbuilding, which is why I didn't include it at first) is a background document styled as an excerpt from a larger scientific journal, describing the steps that were taken ahead of using this pathway for manned exploration (that document will probably become part of a question of its own shortly). Given some of the, ah...*oddities* involved in this process, I want it to be clear that we're as sure as we can be that it's not fatal before humans go through.
[Answer]
We actually have history to guide you, for we as a species have recently developed a new form of transport who's effects on the human body were not understood, which took humans into an unknown environment:
Space Travel.
<https://en.wikipedia.org/wiki/History_of_spaceflight>
We started with a TON of unmanned probes with every sensor we could think of. Then we tried more complex life forms (dogs and monkeys) full of sensors, then escalated to humans in ones and twos and threes. The process took decades, but that was mostly because we had to build new rockets for everything.
I would base any hypothetical exploration of your Physics Tube on the space program; I don't think I could come up with a better research plan than two incredibly driven world powers. As stated in another comment, nowadays we worry more about contaminating other environments more than necessarily contaminating ours, so that has to be kept in mind. Safety would also be of higher concern (no plywood chairs in launch capsules) but don't over-estimate the need for confidence in exploration. While I don't think explorers would happily throw themselves into a woodchipper, one constant theme I've heard from astronauts is that they'd made peace with Death before climbing onto that rocket. Anything could happen, anything could go wrong, and they'd have to overcome that hurtle once we got to it.
In other words, once a few complex critters and computers had survived the passage (computers are more likely to be burned out by microscopic misalignments and whatnot, and they CAN be fully debugged on the other side), explorer humans will be champing at the bit to step through.
[Answer]
**Memory loses** are something I would look into. The pathway may be able to transport cells, but can it transport the key to the complex activities running in our brain at all time ?
Worse, I don't see how you would be able to test that on other beings than humans. They can't describe what they feel they have forgotten, sure you can teach a mice something and see if he has forget it afterwards, but will he really forgot that particular thing ?
[Answer]
The first test would be simple survivability test (e.g. Does a living creature survive the transport?) Upon emergence from the other side, the animal is euthanized, and autopsied. The scientists would do an in-depth analysis of blood, tissue, and structures. They would repeat this over and over until they feel confident of what changes taking the trip has on the animal.
Then they would have the animal pass through multiple times and autopsy it. This checks to see if there is a small but cumulative effect on the animal.
They would do this with different animals (rats, monkeys, pigs, dogs, fruit flies, etc.) Each animal approximates humans in some areas better than others. (note on [animal testing](http://www.animalresearchcures.org/typesneeded.htm))
The researchers would keep some animals alive to study long-term effects of passing through. Here they are looking for any differences between a control group and the test animals. Specifically, they will examine the differences in the rates of death, cancer, infectious disease, and chronic disease. They will do blood tests, and look at organ function. They would compare aging, general health. I would expect a trained animals would be kept to see cognitive effects (how fast [rats run maze](http://www.ratbehavior.org/RatsAndMazes.htm)s, etc.)
I would also expect researchers to keep a population of fruit flies to ascertain what lingering effects transference might have on reproduction, fertility and the germ-line (i.e. future generations.) [Fruit flies](http://www.yourgenome.org/facts/why-use-the-fly-in-research) are used because they are small, cheap to keep, well-understood, reproduce quickly, and model human DNA well.
If the tests indicate that the device is safe, humans would then go through. They would be tested extensively.
Of course, external pressures like economics and war tend to shorten the deliberative scientific approach. In cases such as this, testing would still occur but with less repetition, and a shorter time-scale.
] |
[Question]
[
I have a question for those familiar with the dark arts. I am looking for answers from people with knowledge of clairvoyance and psychic abilities (no matter how they came upon this knowledge!) to help with a specific aspect of my fictional world.
# Magic system
I'm trying to base my magic system on 20th century occultism / alternative medicine etc. This is as far as I have gotten. The magic system is:
* Based on Western occult and spiritualist traditions
* Employed directly, without much intervention from helpers or gods from beyond the grave or from other realities.
For example, my protagonist uses Tarot cards, which sometimes tell the future, and sometimes they influence the future by creating hexes and curses. She carries them around like any other fantasy character would pack a sword or a pistol.
* Does not drain energy, or not in a dramatic way.
* Might use up magic powders or artifacts.
* It just so happens that some people can do it, and those people can use it as much as they like.
A small amount of more powerful magic exists, based on artifacts and powders. These are heavily controlled by governments and international bodies. Hence, the main characters are involved in smuggling magic powders between various coastlines by sea.
# Uses of magic
Although the time period is modern-day, I wish to rid my narrative of modern weapons and firearms.
How am I doing this? Through psychic abiities. The Coast Guard employs psychics, sourced from the military, who are very good at tracking firearms. Which means keeping guns on a smuggling vessel is a sure-fire way to be discovered by the Coast Guard. My characters don't want to get caught. Therefore, they rarely bring guns on trafficking voyages.
My question is:
* **How would the Coast Guard psychics go about their jobs?**
Surely guns are not the only things they can perceive. I am trying to base their abilities on real ideas of what psychics can do. I figure they are most likely to see/predict things with a lot of emotions attached. Also perhaps things with a connection to death or the afterlife. This might explain why the Coast Guard psychics are especially good at sniffing out guns.
So:
* Are there any models of **how a specific psychic ability works**, either generally, or where applied (successfully or not) to **law enforcement** in particular?
I'd like a specific set of psychic abilities employed by a real-life famous psychic or clairvoyant or card-reader that I can use, that would work for the Coast Guard or law enforcement in this context. I feel it's better to have a **plausible model** of how detection/prediction by a psychic might work, rather than just patch something together to suit my plot. Basically I am looking for something that reads true to people who know about / believe in (practice? wield?) this stuff.
Help, please!
[Answer]
## Vedic Siddhis
One widely recognized system is that of Yoga from the Vedic culture of India. When properly practiced, yoga can result in manifestation of siddhis (special abilities).
[The Shiva Samhita](https://archive.org/stream/SivaSamhita/SivaSamhita_djvu.txt) describes a number of siddhis related to perception (see chapter 3 particularly):
* Sukshma drishti (the ability to see non-physical things): this could be useful in detecting if any of the smugglers are doing illegal things in a non-physical plane
* Dura drishti (ability to see far away things): this could be used to inspect ships, watch smugglers, examine cargo holds, etc.
* Dura Shruti (clairaudience): this enables one to listen to smugglers, eavesdrop on their plans, etc.
[Transcendental Meditation (TM)](http://www.tm.org/) and it's advanced techniques, such as the [TM-Sidhi Program](https://www.mum.edu/about-mum/consciousness-based-education/tm-sidhi-program-yogic-flying/) (which includes [Yogic Flying](https://m.youtube.com/watch?v=3nQXVRjMoUE)), are designed to lead one effortlessly to enlightenment, and to the development of such accomplished mind-body coordination that siddhis are a natural result. So, practicing TM and the TM-Sidhi Program are techniques for acquiring siddhis.
The [Maharishi Jyotish program](http://www.maharishijyotishprogram.eu/) is a set of techniques designed lead the practitioner to become intimately familiar with the level of reality known as "[jyotishmati pragya](https://books.google.com/books?id=sT13ws7RKgYC&pg=PA164&lpg=PA164&dq=%22jyotishmati%20pragya%22&source=bl&ots=RZFTSuK2Ub&sig=bH2I2ZF7oO5wfleIJ2O4IGg_vXM&hl=en&sa=X&ved=0ahUKEwiR_ayXm-zQAhXILSYKHULiAlAQ6AEIIjAE#v=onepage&q=%22jyotishmati%20pragya%22&f=false)":
[](https://i.stack.imgur.com/7qBq0.jpg)
When capable of accessing jyotishmati pragya, the practioner can know the past, present and future. This could be used by the coast guard to catch smuggers by knowing when and where smugglers will be, where they keep their guns, etc.
## Difference of Interpretation
One primary difference between schools of yoga is how yoga is achieved. Different proponents of yoga translate Vedic texts differently, sometimes fundamentally differently. For this reason, if you read translations of Vedic Literature made by unenlightened people, it is said you can very easily be led astray in terms of proper practice of yoga.
For this reason, it is recommended you seek out an enlightened Guru. Once found, do anything it takes to become their disciple so one can attain enlightenment in this lifetime.
I mention this in the hope that you, as a writer, don't get confused by many different techniques different translators and teachers publicize. The only reliable modern guidance I have ever found is the teachings and translations of Maharishi Mahesh Yogi, who prescribes effortless techniques like TM.
[Answer]
There aren't a lot of models connecting psychic abilities to law enforcement but there are some abilities that people report which I can apply uses to. Since this is pseudoscientific, people can report what they want and it will be believed; expect some of the items on this list to be unrealistic.
---
## Astral Projection
**Abilities:**
* Having "out-of-body" experiences and drifting to new places, physical or supernatural
* Some may be able to do so with their eyes open and describe what they see
* Others may need to be unconscious
**Uses:**
* Bag checking
* Following suspicious individuals
* Reporting remote problems; general surveilance
---
## Aura Reading
**Abilities:**
* Sensing auras (souls? electromagnetic radiation? supernatural vapors?) around individuals
* Reported somewhat often (not hard to find)
**Uses:**
* Telling if a person is "good" "evil" or some complex alternative
* Determining motives, guilt, etc
* Determining the general safety of a location
---
## Clairvoyance or Scrying
**Abilities:**
* Sensing the present or future of objects, people, places, and things
* May be associated with a sense (one individual may see the future, another may hear it)
* May not work at all times or at will
* May be able to see the metaphysical (ghosts etc)
**Uses:**
* Projecting the futures of those associated with illegal powder distribution; watching the people who buy contraband to identify them if they arrive at customs
* Identifying future threats or attacks on customs by magic users
* Spying on "no fly list" individuals associated with magic to prepare if they will arrive
---
## Exorcism
**Abilities:**
* Summoning and banishing supernatural entities
* May apply to metaphysical entities "ghosts" or physical "demons"/possessed people
**Uses:**
* Processing and potentially removing metaphysical beings; like border patrol for ghosts
---
## Hypnosis
**Abilities:**
* Inducing a dreamlike state
* Making individuals complacent
* May include getting them to do things or divulge information
**Uses:**
* Interrogation
* "Safer" processing
* Bag checking
---
## Manipulation
**Abilities:**
* This is a broad category encompassing things like teleporting objects, making new objects spontaneously, moving the air around you, creating fire, etc.
* Little actual evidence (even pseudoscientific) for this exists so I'm lumping it together
**Uses:**
* Defense
* Bag-checking
* Restraining individuals
* Interrogation / torture
---
## Mediumship
**Abilities:**
* Acting as a gateway between the physical and supernatural; allowing metaphysical consciousnesses to manifest and speak
* Mostly just for communication
**Uses:**
* Identifying victims of crime
* Physical guards (if "posessed")
* Surveillance (this assumes that there are friendly supernatural being who can observe the crime and then report it)
---
## Omnipresence
**Abilities:**
* Being in multiple places at once
* May be physical or mental
**Uses:**
* Surveillance
* Security (multiple strong guards)
---
## Telekinesis
**Abilities:**
* Moving objects and systems with the mind
* May require energy or have constraints
**Uses:**
* Security (guarding places)
* Restraining individuals
* Torture and interrogation
* Sifting through suitcases efficiently
---
## Telepathy
**Abilities:**
* Intercepting human thought
* Communicating via thought
* May or may not be clear that a telepath is observing you at any given time
* May also work on animals
**Uses:**
* Spying at any place or on any level
* Interrogation and torture
* Long-distance communication
---
[Answer]
May I say some different key words that you could google, so you can find a method that rings a good bell in your own Mind?
Astral projection/shamanic journeying, lucid dreaming, crystal gazing, tea leaf gazing, cloud gazing, fire gazing (like in the red priests/priestesses in The Game of Thrones), bone throwing (used in ancient China), black mirror gazing, smoke gazing.
Maybe the psychics would like to draw a circle of protection first, using the four elements (Earth in the north, Water in the west, Fire in the south, Air in the east). A stone in the north, bowl of water in the west, lit candle in the south, feather in the east).
I would choose the astral projection root (because for me it is something I am familiar with), where they would breath in a specific way while completely relaxing the body, draw white light throughout their egg shaped aura (for protection), descend to the underworld/spirit world (always through the same entrance) meet their spirit guardian/s, and get help from them, or be escorted by them to get the information from another astral being(whether an animal spirit, alien, faerie or god/goddess. It would be nice to offer a gift in return for the information.
] |
[Question]
[
If I've recently started a colony on a somewhat habitable, but uninhabited planet, what's the best way to determine the location of any ore or other subterranean resource deposits?
The planet is Earth-sized and of similar composition. It's a similar distance from a similar star, but much younger. Temperature-wise, it would be habitable, but life on the planet is still mostly composed of bacteria-like anaerobes and there's insufficient oxygen for humans to survive outside without supplemental oxygen tanks.
The settlers have access to near-future technology and have ample time to research and test the planet before going there. They've got plenty of funding for rovers and satellites and can deploy a large number of each. They'd like to establish a long-term settlement on the planet, and as such, they need to locate suitable reserves of construction and manufacturing materials like titanium, gold, and rare earth metals.
What's the simplest and quickest way for the settlers to accurately survey their new planet? What sort of technology that's feasible in a near-future setting would need to be developed in order for them to properly survey their new home?
[Answer]
## Gamma-Ray Spectroscopy
One newly developed technology, [gamma-ray spectroscopy](https://news.vanderbilt.edu/2015/11/19/new-detector-perfect-for-asteroid-mining/), is supposedly capable of doing just what you want. This is a new technology just recently developed, and is being publicized as destined for future asteroid mining by companies like [Planetary Resources](http://www.planetaryresources.com/#home-intro):
>
> The technological development is a new generation of gamma-ray spectroscope that appears perfectly suited for detecting veins of gold, platinum, rare earths and other valuable material hidden within the asteroids, moons and other airless objects floating around the solar system – just the type of “sensor” that will be needed by asteroid miners to sniff out these valuable materials.
>
>
>
If atmospheres interfere too much with naturally occurring gamma rays, perhaps man-made mobile gamma ray generators could be used used with spectroscopes.
## Spectroscopy Using Other Wavelengths
I imagine spectroscopy of this type will expand in capability as technology evolves and need increases. [Terahertz spectroscopy](https://en.wikipedia.org/wiki/Terahertz_spectroscopy_and_technology) is being developed quite a lot recently, and I'd expect science will attempt to harness every conceivable wavelength as much as possible.
[](https://i.stack.imgur.com/c8hlv.jpg)
Currently, science has a fairly good working knowledge of the electromagnetic spectrum, and I imagine as more knowledge of other [fundamental fields](https://en.wikipedia.org/wiki/Fundamental_interaction) (such as gravity) becomes better understood, that knowledge will be applied to this problem as quickly as possible.
[](https://i.stack.imgur.com/k6t8V.jpg)
Since every element has it's own unique weight, perhaps something like gravitational spectroscopy could one day be a possibility.
[Answer]
## We can already do this *without* paying for new tech
While developing newer technologies may work (as cited in other answers) the development of technology is costly - and for a mission which will already cost billions, why not use what's **proven to work** instead?
## Take a look at the [Mars Reconnaissance Orbiter](http://mars.nasa.gov/mro/) (MRO)
It can take care of everything your question describes, in detail.
**Location of Surface Minerals**: See the [Compact Reconnaissance Imaging Spectrometer for Mars](http://mars.nasa.gov/mro/mission/instruments/crismcompactreconnaissanceimagingspectrometerformars/) (CRISM)
This instrument searches for specific surface minerals in 18 meter-wide areas - more than small enough for rovers and subsequent colonists to visit and confirm.
**Composition and Layout of Terrain**: See [High Resolution Imaging Science Experiment](http://mars.nasa.gov/mro/mission/instruments/hirise/) (HiRise)
This instrument can also identify groups of minerals in areas as small as 1 meter - extreme detail - as well as show what terrain looks like, which will help your miners figure out if they should, and how they will, get there.
**Deeper Deposits**: See [Shallow Radar](http://mars.nasa.gov/mro/mission/instruments/sharad/) (SHARAD)
This instrument observes features up to a kilometer underground, and is sensitive to the characteristics of specific substances.
---
In summary, there is **no point** in developing or investing in other technology. If this mission will cost as much as it appears, you should just use what's **proven to work**.
[Answer]
When doing this on earth, there are a variety of techniques:
Techniques possible from space:
A: Aerial photography. Several of the world's big iron and nickel deposits are associated with very old meteor strikes. (Sudbury Nickle deposit is the big one I know of.)
B: Gravity anomalies. A metal deposit is more dense than the surrounding rock. A big deposit creates a slight irregularity in the gravitational field. These can highlight areas that merit closer attention.
C: Magnetic anomolies. Works only for some types of iron ores.
Techniques from the surface:
The problem with surface checks is manpower. But given reasonably sophisticated drone technology, it should be reasonable to send out a swarm of drones, that do spot checks on exposed rock, zapping it with a moderate power laser and reading the spectrum from the plasma.
Drone tech also can fine tune the gravity and magnetic anomalies.
If you are at a level of just unicellular organisms however, you may be somewhat handicapped. Read up on ore body formation. Good number of theories involve activity by microbes to create the ore body.
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Suppose there was a disease which didn't destroy humanity, but which mentally crippled all humans over the age of 10, rendering them incapable of mental activity beyond the level achievable by rabbits. Essentially, all humans would lose the ability to do anything but eat and reproduce once they reach 10 years of age. Anything more complex, like tool use, speaking, or teaching, would have to be done by children.
Young humans, though, even by the age of 7 or 8, are still more mentally capable in many ways than most non-human animals are. They can do fairly complex math, have fairly developed lingual abilities, and are capable of reading and writing well before that age. They're big enough and dexterous enough to handle guns and can catch food for those members of society that are too old to take care of themselves.
In this scenario, could the children develop society to the level we have today? How far could a society develop, if all of its productive members were children?
[Answer]
I imagine such a civilization could become quite advanced, but not easily - and not without some truly nasty tradeoffs.
So, there are ten year olds who are quite advanced, can think and plan at an adult level - but there are also ten year olds who are decidedly not. Given time, training, pressing need, and, eventually, a culture which expects them to fend for themselves, I suspect most ten year olds will be able to manage to survive themselves, and contribute to a working society. However, this will not be the case, initially. A lot of people would be lost in the wake of the disease, including a lot of children... and even after things settle down, the kids will be in survival mode for a long time as they try to survive, long before building up a new society. Getting back to the first point, those kids who aren't especially advanced (moreso emotionally than intellectually, this is about kids who can't or won't do their work, not those who can't solve complex problems) will likely not survive - and those who are, will have to let them die. It's a survival oriented equation, and kids who will survive and who lead groups who will survive are going to have to be ruthless - which will persist into the surviving societies.
In any case, one point I don't think you quite see is that, your kid-civilization is going to be, essentially, *domesticating* the adults. They are not going to have the resources to subsidize these unproductive mouths, and additionally, are not going to see any reason why they should for a very, very long time. If they have kids who are very clear headed, long thinking, *and also* really well educated about reproduction and genetics and diversity, minimum sustainable populations, and a host of other stuff, they might keep food out for *feral* adults, or once they have surplus, keep feeding people till sixteen or so (breeding them so they will have kids in the tribe's reach), and then letting them go. Even if that means letting the feral adults starve, or be prey to predators or each other. Well, they might use them as draft animals for heavy labor, or just killing them instead, I suppose - but the point is they will be treated like, and thought of like, domesticated animals.
For a long time, past the point of the kids forming self-sufficient tribes and up to the point of keeping track of sustainable numbers, the population will be surviving mostly by adopting the kids born of whatever feral adults may have survived. This means you should probably figure out how well these adults are surviving and/or capable of raising kids on nothing but instinct - after all, rabbits do survive quite handily, so it isn't impossible. Maybe the kids will keep track of, or temporarily care for pregnant women, if they know or somehow figure out they need more people in their groups, but they will not keep adults long term - they haven't the resources. And once they get to the point where they do know they need to keep the population up, they won't be caring for their adults, they will be breeding them for offspring - they will not consider them *people* anymore.
Also, it begs the question of why ten year olds, specifically. It would actually make a lot more sense to tie this to puberty, even if you want to have the average age of puberty, or some necessary pre-puberty changes which act as the trigger, happen around ten (I think ten is actually the lower bound, so minimal handwaving if you go this route). It can make a story-point whether the oldest are kicked out before they lose their minds, or after, or are kept for some time as breeders - which an odd several-year gap between losing their minds and reproducing. Also, if it gets tied to puberty, you might end up with an odd age creep going on, where those who are late bloomers survive *much* better. You likely won't buy more than a couple years this way, but it will help if you get even occasional twelve or fourteen year olds in your tribes.
So, your little-kid-tribes will be adopting little ones out of the wild - maybe toddler age, maybe finding abandoned infants, depending on how well your adults actually function. Little kids need care, and teaching (and this is also work). Your tribe will need people to manage the food supply - hunting, foraging, farming, they can all be options as your societies evolve. Kids will simply not be capable of the same amount of heavy labor an adult is, but with clever use of tools and draft animals (potentially including feral adults) they should be able to manage - and they will also not need as many resources as an adult would, including smaller dwellings, clothes, and meals.
The amount of time left over for innovation and advancement will be small, since even becoming more responsible younger and reaching social maturity early will not give the same kind of time-span to achieve things in, so society will advance slowly - though you might, maybe, get an artificial boost from leftover teachings or materials left over from the society before the disease.
And your society is going to be ruthless. Kids won't have the resources to be otherwise, especially in the immediate aftermath of the disease, and that will carry over into their civilizations. Also, kids tend to see the world in black and white - they won't have time to finish developing and get enough experience to be otherwise. So ruthless, they'll be hard on those unproductive, and unforgiving of defects (mental or physical). They will have to exile their adults, or otherwise move them from people-status to draft-animal-status - this will effect their empathy, they can't afford to be otherwise but they will also have little sympathy for those who won't, or can't, do their fair share - and will have practice at moving others from people-status to not-people-status, it will be easy for them to dehumanize others.
[Answer]
Probably not.
Children can do impressive things like building houses, handle a farm and developing a writing system. But children hardly would domesticate animals like wild horses or cattle. Even birds like ducks or chicken would make the children struggle to handle them, because of their weaker bodies.
Beside that, with no adults to protect them from wild animals or themselves(accidents, deceases and stuff like that), the mortality rate would be huge, like it was until the industrial revolution.
Probably their civilization would consist of small houses and small farms with a certain organization. They could develop a legal system, based on democracy, where every children would vote.
Their judgements could be based on it. I guess in this point, they could make things work. But they would not have the power to build impressive things like our normal mankind.
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[Question]
[
Other questions about this are on [this meta post](https://worldbuilding.meta.stackexchange.com/questions/4101/machina-plague-series/4102#4102).
>
> **Context (Updated with new information based on Q1)**
>
> In an act of war, an advanced, extraterrestrial species has designed the *machina plague* - an infectious nanobot pathogen - to
> wipe out the human race. They will release 10,000 nanobots on January
> 1st, 2017. Every bot will be located inside one nondescript, human
> host in Haneda Airport, Tokyo. Release will be at local time.
>
>
> *Spread:*
>
>
> * Bots do not effect the host directly after infection in order to reproduce.
> * Health effects occur gradually after required number of bots is reached. Reaching this number may take between 8 and 24 hours after infection. Symptoms reach a sustained peak approx. 30 minutes after the first symptoms occur.
> * Plague is both waterborne and airborne, but bots will only reproduce in human blood
> * Outside of the bloodstream they will survive for up to 48 hours before losing power and shutting down; they may be revived if re-introduced
> * Bots can permeate flesh to reach capillaries
> * Bots reproduce using iron, manganese, lead
> * Hosts infect the bloodstreams of other humans using fangs
> * Hosts may also come in contact with other hosts' skin, or release bots into the air through respiration
> * Only humans can be infected, but other animals may be prey to hosts
> * Bots coordinate with other hosts' bots in proximity; no attempts to infect hosts occur.
>
>
> *Host Changes:*
>
>
> * Bots lobotomize the host brain; preserve feral instincts and locomotion
> * Bots reroute nutrients inside the body to form fangs, tubes
> * Hosts prey on animals for food
> * Bots repair host if injuries are deadly or life span is exceeded
>
>
> *Weaknesses:*
>
>
> * Decapitation separates brain from body, meaning no acquiring food; bots eventually become dormant
> * Stake through the heart stops blood flow; organs die before bots remove stake, causing eventual death
> * Hosts hide from sunlight, which reveals the structures beneath their skin
> * Nanobot communication signals can be detected - identifying a host
> * Signals can be jammed, making hosts attack each other thinking they're more humans
> * Strong EMPS may quarantine large areas as a last resort
>
>
>
---
**The second question in this series:**
Assuming the scenario provided in the context is feasible, what negative health effects will the host contract that may inhibit the spread of the plague? Would things such as reduced blood iron, reduced red blood cells, brain alterations, etc. be enough to severely inhibit the hosts, and thus the plague itself?
How would you fix the information in the context so the hosts can be maintained?
[Answer]
My biggest concern is what happens to all of the host blood cells that the nanobots destroy in order to reproduce? Does the host body continue to produce new blood cells to replace the ones that were destroyed?
**Most importantly: how does the new system handle providing oxygen to the host cells throughout the body?**
As far as health risks for the host... unless the nanobots REPLACE the functionality of the blood cells and carry oxygen throughout the body, the body would suffer from [hypoxemia](https://en.wikipedia.org/wiki/Hypoxemia) to start, and eventually the biological components in the body would start to shut down.
[Answer]
Nanobots should act faster in adults, slower in kids. Kids are unlikely to think of a cure or isolation strategy. They can be disease vector for a long time without being a threat. Adults are more of a risk.
The bots are more intelligent than viruses... they could listen to the speech of a host... as soon as a host sounds like they know anything about virology or tactics, accelerate takeover of that host, or even sacrifice that one host so it doesn't create defense for the rest of the humans.
[Answer]
This is not a virus evolved to reproduce itself as efficiently and quickly as possible, this nanomachinery is designed to spread and infect, meaning it's alien creator would have wanted to avoid the host realising he/she is sick before becoming feral and starts infecting others. Strong symptoms are a giveaway of serious sickness and compels us humans to seek assistance, so the nano machines would probably cause the least amount of damage to the host's metabolism to avoid symptoms more serious than a common cold before they multiply enough to take over the brain. Then, they would numb pain receptors and such to make the feral host keep going as strong as possible for as long as posible.
[Answer]
Given:
>
> • Bots reproduce using iron, manganese, **lead**
>
>
>
emphasis mine, and
>
> ...but bots will only reproduce in human blood
>
>
>
I would say requiring lead in your blood to reproduce would slow the rate of spread as lead has some pretty [well known](https://en.wikipedia.org/wiki/Lead_poisoning) negative health effects.
While you might see outbreaks in [some areas of the world](https://en.wikipedia.org/wiki/Flint_water_crisis) with poorly maintained water systems, or in factory workers who work with lead containing products (paints, batteries, etc.), most healthy people would seem to be poor hosts to this techno-disease.
Of course if people start shooting the un-symptomatic infected, this could have the unintended consequence of providing a source of available lead and might trigger a number of rapid transformations to fully symptomatic carriers.
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I'm creating a fantasy world (dragons, giants, generally medieval, generally rare magic, potential inter planar travel), and I would like the world shaped like a donut. Obviously I could just say "The world is magically sustained as a torus" and be done, but I want to know what magic needs to be there before getting too far into it.
Since I'm allowing inter-planar travel, I'm starting with the concept that the torus is held together by a ring in its center that contains millions of nodes that can transport to different planes/planets. The gravity from these planes leaks through causing the torus to maintain cohesion, and not form into a sphere.
Other problems I know need solved:
1. What prevents the atmosphere from being ripped away?
2. How do orbits of stars/moons prevent collisions?
So the question is: what handwavium/magic is needed to sustain a torus big enough that stars (could be singular if that makes more sense) and moons (several) orbit from the inside to the outside of the torus? Bonus: What other physical characteristics are reasonable for such a planet? (Tides, diameter of the donut, diameter of a slice of the donut, temperatures, weather, etc.) Double bonus: reasonable solutions to the physical issues. :)
Notes:
The torus big D diameter is light minutes to light hours across.
The torus little d Diameter is probably significantly smaller than the earth because gravity is "leaking" through the magical nodes or portals.
[This question is similar, but calls for a much smaller planet.](https://worldbuilding.stackexchange.com/questions/6465/what-would-the-problems-with-consequences-of-a-torus-shaped-planet-be)
[This question has some great thoughts about physical characteristics of a normal spherical planet.](https://worldbuilding.stackexchange.com/questions/15062/stumped-how-can-i-get-a-huge-earth-like-planet)
[Answer]
You're going to have an *enormous* gravitational problem. The inner part of the torus, for example, is going to have virtually no gravity except the illusion of it produced by the torus' rotation - effectively, residents of that inner part would seem to be inside a shell, and gravity from different parts of the torus would cancel each other out.
If you spin the torus fast enough to create the illusion of normal gravity on the inner side, and make the whole planet about two or three times as massive as Earth, you'll get normal gravity on the other side, too. Now, in between, the gravity will just be bizarre, pulling a little askew depending on where you are.
I don't know what you mean about *stars* orbiting - do you mean actually the stars in the night sky? Because if so you're talking about things *light-years* away passing through the center of the torus, which makes the torus bigger than any contiguous structure in existence by a factor of like thirty orders of magnitude. If you just want the sun to orbit, you've still got a problem - either the planet is so big that it would take billions of years to circumnavigate, or the Sun is so close that the atmosphere boils away. So you'll have to have some sort of alternate version of a star.
Moons are easier, by a long shot - a moon will orbit the center of mass, but it can be in a wildly elliptical orbit. Make the orbit so elliptical that it nearly passes *through* the center of mass, and you've got your orbiting moon. Problem is, at the other end of its orbit it'll probably be so far away as to be invisible.
To be honest, if you want a pseudo-scientific approach to this, I'd suggest delving into old cosmology. For example, a modification of the classical "crystal spheres" model of the cosmos would work nicely - your torus could have a crystalline medium flowing around it, carrying celestial objects through the center or wherever the heck you want. Otherwise, the best advice I can give is to say "okay, gravity works completely differently in every way".
[Answer]
I'm assuming you want a relatively constant gravity throughout the whole of the world...not constantly changing gravity as you traverse the planet. So I'm going to chuck out the reasonable physics and give the magic route. The key thing here is the planet itself isn't a torus, magic just gives the image that it is and we are going to rely on planar travel to do so.
The setup is going to be two overlapping planes. From 60 degrees north to 60 degrees south, the planet behaves as normal (travelling east for long enough will get you back to where you started). At 60 degrees north or south however, you exit this plane (can be anything from obvious planar travel to a completely seamless transition where you don't even know you crossed planes) and enter a second plane. This second plane exists as it's own planet (you can travel east until you reach the same spot you started at), just smaller as to mimic the inside of the torus vs the larger area of the outside. Using planes...the second plane can easily be the inside of a ring (rings rotation causes consistent gravity). Travelling east on the second plane will eventually get you back to your starting point.
This setup will give the image and feel (from the surface anyway) that this world is a torus. Starting from the outside world at the equator...travel north to 60 degrees and find yourself entering the north side of the second plane. Travel south across this plane and end up back on the first plane at the far south and continue travelling north until you hit the equator for a full round trip.
Of course this world won't look like a torus from space, but from the ground it will feel like it.
[Answer]
Little to None... There is a way to make Toroidal planets in reality. The problem is that they're unstable and easily disrupted. Just throw up a force field, magic or otherwise, of some kind and you're good.
I don't like the site, but here's a link to an article on the subject:
<http://io9.gizmodo.com/what-would-the-earth-be-like-if-it-was-the-shape-of-a-d-1515700296>
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I'm trying to figure out how a nuclear war in the north hemisphere would affect the south (specially South America, where my story is set).
I read about the nuclear fallout and nuclear winter consequences, but all I saw is that the southern hemisphere wouldn't suffer that much apart from minimal climate changes (and only for a few months - correct me if I'm wrong).
What I need is a event that would trigger nuclear winter in South America, but not killing people in mass **in that area (in a practical way, anything can be devastated, except South America)**. Like I said, I was hoping that a nuclear war in the northern part of the world would give me this effect, but my research concluded that the damage would be medium to minimal, and just for a few months. Of course a full-scale nuclear war would lead to that, but it would mass-murder the entire world.
**How a nuclear detonation/war could lead to winter in South America? How "big" or "exceptional" this event would need to be?**
Thanks!
[Answer]
I would refer you to the 1957 post-apocalyptic novel [On the Beach](https://en.wikipedia.org/wiki/On_the_Beach_(novel)) and its [1959 film version](https://en.wikipedia.org/wiki/On_the_Beach_(1959_film)).
>
> The novel details the experiences of a mixed group of people in
> Melbourne as they await the arrival of deadly radiation spreading
> towards them from the Northern Hemisphere following a nuclear war a
> year previously.
>
>
>
You have to consider, that we are an interconnected planet. Even isolated atomic accidents can reach other hemispheres. It is not only the wind, but consider propagation through water currents, rivers. Fauna that survives would probably migrate carrying the poison with them.
I do not know how to calculate the spread rate, nor the maximum damage to the north hemisphere to prevent damage to the south, but if your scenario depicts destroying the north by anything other than accident, you can expect there would also be plans to destroy potential supplies from the enemy, i.e., the south.
In any case, I would be interested in reading your story.
Good luck!
UPDATE: For a more scientific or precise description of the nuclear winter process and requirements, I would suggest the following article [Nuclear winter](http://climate.envsci.rutgers.edu/pdf/WiresClimateChangeNW.pdf).
[Answer]
If you think the nuclear winter is not enough to have a heavy impact on the south, why not have one nuke hit Yellowstone and trigger the volcano?
Where a nuclear or a volcanic winter might be northern hemisphere only a combination of both should/ or at least could be big enough to cool down the south, too.
One important thing to remember is that even a "slight" cooling of only 1-2°C can disrupt crops not meant for this new climate.
And in addition to that the weather could change if the temperatures drop.So not only do the crops get too little warmth, they get the wrong amount of water, too. Same for cattle, the change in temperature can cause them to become ill.
[Answer]
take a look here : <http://science.howstuffworks.com/nuclear-winter2.htm>
The article details six levels of nuclear winter: Minimal, Marginal, Nominal, Substantial, Severe and Extreme (in the final case everybody and everything dies). For most of these scenarios; the conclusion from their analysis is based on this fact:
>
> Everything below the equator would remain mostly unaffected, given the hemispheric separation of air currents and the fact that most nuclear targets exist in the Northern Hemisphere.
>
>
>
The worst level for which humanity will likely survive is this:
>
> **Substantial nuclear winter:** This scenario, following full-scale nuclear war, involves catastrophic consequences for the Northern Hemisphere: freezing temperatures, widespread fallout, pollution, ozone depletion and disrupted precipitation. Imagine a deeply overcast day -- now imagine those conditions persisting for years. Green plants would barely receive enough sunlight for photosynthesis. Crops would fail, billions of humans would die, species would go extinct and while humanity would likely survive, civilization as we know it might not. Damage to the Southern Hemisphere would depend on the number of detonations below the equator.
>
>
>
In other words, the most plausible outcome for full-scale nuclear war is a hellscape in the Northern Hemisphere (where nearly all the major cities are) and a lightly damaged Southern Hemisphere (South America, Australia, the southern third of Africa, New Zealand, many islands).
If the Southern Hemisphere does suffer Nuclear Winter, it would be one of the earlier levels: Marginal would be plausible. You can look at those to see how much damage would likely occur in South America (or the southern hemisphere in general). Perhaps any big cities or major population centers would be bombed in a full scale war (thousands of nuclear bombs).
I live in Argentina and I think all here in South America would have to accommodate many people, basically anybody that survived in the Northern Hemisphere. The current population is around 420 million, perhaps tens of millions more would be refugees. This could trigger revolutions and new political orders and alignments, which may or may not be good.
[Answer]
If a nuclear winter would hit the northern hemisphere only, then the survivors of the war would all head south. Lets say 50-100million north americans all walk into South America. That kind of migration will lead to mass riots, mass starvation and a complete breakdown of society as we know it.
I think I'd prefer the winter..
[Answer]
<http://www.uow.edu.au/~bmartin/pubs/82cab/>
Talks about the impact of nuclear war on Australia
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I wonder if there is a stable star-moon-planet system where a specific area of the planet would be permanently covered by shadow. I'm not looking for a common tidally locked planet with a roughly 50% dark zone. This is the desired order of preference for my world:
1. Most of the planet has a traditional day-night cycle, except for some area which is always covered by night (like the Australia continent, or China).
2. Most of the planet has a traditional day-night cycle, except for one or more vertical stripes of it (ex: GMT-3 is always covered by shadow).
3. Instead of a tidally locked 50% covered by shadow, say, 25% is permanently covered by shadow, 25% is always bathed by sunlight, and the other 50% has a day-night cycle.
4. Ok, I give up. Just a tidally locked planet between two stars, so there are two 25% areas covered by shadow and 25% in-between with light. Is this possibly stable?
I'm willing to allow any non-conventional (but non-magical) feature to this system: large moons, more than one sun or even a torus planet topology.
[Answer]
While this doesn't meet any of your stated parameters (specifically the permanent requirement) and I have zero background in this field, I figured I'd post anyway :)
Uranus has a massive axial tilt that gives its poles 42 years of darkness followed by 42 years of sunlight. Someone else may want to comment if speed of rotation can affects the time, what a moon system might do, etc.
Source: <http://www.universetoday.com/18955/tilt-of-uranus/>
[Answer]
If you are willing to have large-scale artificial structures, it gets a lot easier. For example, a planet whose equator is coincident with the plane of its orbit, and has a large solid, artificial ring in geosynchronous orbit would have its equator in permanent shadow.
[Answer]
As mentioned in the comments:
A moon or satellite (artificial or no) is tidally locked to your planet, and your planet to it. So the system turns in a "day" and the two bodies always show the same face to each other. The system needs to be exactly in the plane of the solar system so that a solar eclipse will happen over the same place every day.
Unfortunately the sun would be visible in the morning and evening.
[Answer]
I believe a rogue planet could find orbit a binary system where said planet rotates in a way where it's equator is dark and poles get plenty of light (because the orbit is equidistant from the two stars masses in a small orbit). This pic shows the concept (sizes not depicted well :P ):
[](https://i.stack.imgur.com/TTfSm.jpg)
[Answer]
How about planetary rings? If the planet and ring system had only a small axial tilt then a horizontal band near the equator would be in perpetual shadow.
[](https://i.stack.imgur.com/RS3kc.jpg)
Other more complex configurations would also be possible, but wouldn't quite result in 100% permanent shadow, or at least I can't picture any specific configurations that would.
[Answer]
Earth's moon does have some small areas like that. Requirements are:
1. Rotation axis near zero tilt to the orbit.
2. Craters or large mountains near the north or south pole.
The tilt means the sun never rises much above the horizon at each pole, and some areas there could have a mountain in the way at any given time of day. If you want to arrange it so, you could also have some nearby areas get sunlight only for a few minutes a day with an appropriately positioned canyon.
The only issue would be the atmosphere, if the planet has one, would still supply twilight illumination to the area.
Some of our moon's southern craters have areas that can hold surface ice because they never get direct light, so it never warms up to melt or sublimate the ice.
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Say you are 30 years old, and something happens and you wake up and find that you've been transported backwards in time to when you were a teenager [you were inadvertently sent back, you do not have control over the process or if it happens to you]. Physically, the whole world appears to be exactly as it was the first time you were a teenager: your surroundings are identical and your outward appearance is identical to how it was. However, your brain is different in the sense that you have your 30 year old pre-transportation brain: you remember everything from your life that happened up to when you were 30 and were transported back in time.
From talking with people around you, it seems like they did not have a similar experience, i.e. they were not transported backwards, so they do not realize that a jumpback event occurred. However, you cannot assume this is true of everyone, i.e. it is possible that some other people were also jumped back. In fact, you should assume that at least some other people also were sent back, you just don't know how many or who they are.
1. What are some very concrete steps you need to take to conceal the fact that you were jumped back? This involves 2 parts: hiding the fact from other unsuspecting people, and hiding the fact from other people who also jumped back.
2. How could you identify other people who jumped back without revealing that you were jumped back?
\*\*It's true that if you had technology to see the structures of a person's brain, you could determine that a given brain is unlikely to belong to a person of a given age, and use this to classify people as jumpers/non-jumpers. But I'm mostly interested in other methods besides physical brain structure. E.g. taking advantage of assumptions that a jumper might have based on world events they experienced, such as "accidentally" knowing who Obama is even though the year is only 2002, or "accidentally" knowing that some sports team won X championships when in the present year they've only won X-2 championships, or Googling movie or song or book names before they were published, etc.
\*\*\*Also, how does this change if we don't assume that the jump increment is the same for all jumpers? E.g. you may have been jumped back by 15 years, but another person may have been sent back 5 years, or 50 years.
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If it is your past, you won't have any trouble. You will adapt well. But depending on your social status this could be an immensely traumatic experience. Imagine loosing your child, knowing that you will never see him/her again.
To find others, or rather for others to find me, I would sing songs from the future in a convention of some sorts; making sure that a lot of people would listen to it. For most, I would be a one shot wonder, but those few who had experienced the alternate future, they would know about me.
Also, you going back in time may change the outcome of everything, including teams winning/loosing matches or presidents not getting the office. Things that are quite certain would happen the same way. But others triumphed by a few percent may go the other way. I will call this bubble of change. As you are changed, everything around you will be affected, and in time this bubble will grow and eventually, time streams would be quite different after sometime.
Edit: A similar concept was used in <http://www.kongregate.com/games/StuStutheBloo/no-one-has-to-die>
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Hiding Won't be hard, true you would have some memory problems at first but most people would just think your confused and would not jump to the conclusion that your a time traveler. As time went by surround by your teenage life your brain would start bring bake to you all the memories you had for gotten.
Not sure how to find other like you other then to watch out for people look confused or can't remember yesterday or start showing new skill that should take several year at least to learn
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I think you'll have a difficult time hiding that *something* happened, though non-jumpers are unlikely to guess the details of it. For one thing, if your parents are alive when you're a teenager, they are almost certainly going to notice the sudden shift in demeanor and behavior. The mindset of a 30-year-old is vastly different from that of a teenager (well, for most people anyway...) so the rather sudden shift is going to be jarring for everyone who knows you. If I saw this in my child, I'd probably guess something deeply traumatic must have happened to cause such a dramatic change.
If you want to try to identify other jumpers without revealing your own nature, one option (as others have mentioned) is to look for signs of unusual prescience in folks who are less careful about hiding. The tricky thing about timelines, though, is that actions may well change them. Even worse, if your world has a multiverse structure, the different jumpers might not even come from the same facets of the multiverse, having jumped back from different branches of possible realities.
In that latter case, what you're left with is looking for signs of people who had dramatic shifts in behavior/personality, perhaps at around the same age as you (working on the premise that it might be age-specific.) For instance, this might result in trips to see a therapist instigated by worried parents. Or maybe find stories of people who were doing poorly in school, then suddenly became excellent students. Or possibly look for stories of awkward nerdy kids who rapidly showed a huge jump in confidence and poise. Perhaps even look for stories of prom queens who abandon their cliques overnight in favor of different pursuits. These kinds of things will be easier to spot if they happen at your own school, but some shifts might be sufficiently dramatic to result in news articles in local papers.
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In [the novel I recall](https://scifi.stackexchange.com/questions/139358/novel-about-character-reliving-his-life), he (and the person he already found) posted a newpaper ad with the “remember when” theme, listing slogans from the future. A few replied with wrong ideas about what the ad was concerning. One replied with proof of his own, adding *Tylonol Scare* and *Princess Di* to the list.
Posting such an ad would be a good idea. Though it could be better couched as a legitimate ad for something. It gets people who share your memories to notice that fact, while being unsuspicious to the masses.
It also helped that they knew which stocks to buy for long-term investment, simply from remembering brand names in the future. Investment consultants were the cover they used when visiting the other guy they had found (who was in an institution for the criminally insane, BTW).
Oh, he found the first person (his companion in the rest of the novel) from a movie she had made. It was a huge blockbuster, and he remembers themes from movies that were later in time in his original future. In the credits [he notices famous (to him) people who were as yet unknown at this time](https://en.wikipedia.org/wiki/Replay_(Grimwood_novel)), indicating that the filmmaker somehow was able to pick them out before they became famous.
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I would conceal myself (and temporal point of origin) by engaging self-hypnosis techniques to more fully recall exact mannerisms, expressions and current events, and implant inhibitions that made it difficult or impossible to discuss things that would give away your status, i.e., no reference to things like Blu-ray, flat-screens almost all references to todays pervasive technology like smart phones. I would also watch for others by looking for 'unknown' buyers and investors in dot-com bubble stocks or futures, people cashing in on the ultimate insider information. Once located, I'd approach them with caution, but using specifics in small talk, like *" I'm gonna make Mexico pay for it - it's gonna be 'Yuge'"* find what they know, and find out if if there is a way home again...
Just my opinion
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Are you wanting to look for *any* jumpers, or in particular for any of your companions who may have jumped back along with you?
For close companions whom you met in later years, you may know or have been told their parents' address (and they similarly might know yours). You could write them a short note, with no return address, along the lines of 'Hi, it's Sam! I'm back staying with Mum and Dad again. Drop me a line if you want to get in touch.' Then if they have also jumped they will understand the message, (hopefully) remember your address, and will write back. If they haven't they won't understand it and will ignore it.
For people you already knew as a teenager, it will be pretty easy to look at their behaviour and see whether it has changed – and in particular if any memorable event involving them goes a different way.
I'm wondering why you want to conceal your jump. Is it simply that you don't think anyone will believe you and you want to blend in, or are people aware of jumpers and prejudiced against them? It will be much easier to hide your true nature under the first circumstance than the second.
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In this world FTL travel is accomplished by entering an alternate dimension, let's call Aqua. Aqua is a very simple, albeit strange dimension. A great expanse of water as far as civilization has mapped stretches out, dotted with islands, and an ocean floor. Not a planet, just a strange expanse of water.
Different locations along an X-Y plane in Aqua correspond to specific locations along an X-Y-Z space in the main (normal) dimension. The center-of-mass of the object exiting Aqua has to be roughly (only roughly) sea level, and likewise an object entering Aqua always enters roughly sea level. This allows trips of thousands of light years in the main dimension to be reduced to simple months of travel in Aqua.
Gates can be opened up between the main dimension and Aqua, and the gates are designed to hold the water and atmosphere back, creating a barrier for the water. Gates can only be made sufficiently removed from gravity wells, thus being limited to space.
How Aqua works, as how the jumps to and from aqua work, and the general nature of Aqua are all outside the scope of this question, unless they'd affect the design requested at the end of this post. Consider it all handwavium.
What *is* within the scope of this question is what the vessels would be constructed like: this is a question about design.
Points of consideration:
* Movement in Aqua: Floating like boats? Submarines? Like aircraft?
* Vessels need to be designed for the lack-of-atmosphere in space to the pressures of Aqua (similar to Earth's)
* Vessels need to be designed to be able to accelerate/travel in both space and Aqua.
* Trade transports should be constructed as economical as possible.
* Space military vessels need to be able to protect themselves or be protected in a sensible fashion both in space (obviously), and in Aqua. Military vessels might be carriers, transports, or vessels meant for direct combat.
...What would be a sensible design for these vessels?
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Take a look at how we move cargo around on earth - we don't have amphibious 18-wheelers running cargo across the ocean to stores on land, we have a network of ports, trainyards, and distribution centers. I'd imagine something similar for Aqua - the gates would be like ports, where spacecraft in normal space arrive and transfer their cargo/passengers through the gate. On the aqua-side of the port, they'd be loaded into planes or freighters for long-haul trips. If the gate is underwater, they'll be loaded into a submarine or aquatic elevator to reach the gate from a surface terminal.
However, it does make some sense to move spacecraft through Aqua. If you have a port that's underdeveloped, or a gate that has just opened and needs ships to explore the far side, you might have a fleet of Aqua-side Spacecraft carriers, designed to haul complete, functioning ships through Aqua, in much the same way there are car-carriers and Ferries on earth.
*Special thanks to Erin Thursby for reminding me that infrastructure needs something to build it*
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The first thing that jumps to mind is that if you have the tech to create a barrier that would hold back the water pressure of a huge expanse of water and still have it be penetrated by the site spaceship then what is stopping you from putting one of these "field generators" or whatever it is in your spherical ship and thus removing the problem of water tight and airtight. The field of would simply prevent the water from touching the ship.
Another thought that I had was maybe in this water world you find an element after visiting the first time that is one hundred percent hydrophobic and/or repels hydrogen molecules for some strange reason again simply making the vessel unaffected by the water and only affected by the pressure, at which point you take a submarine design make it out of this element and slap some thrust engines on it. (crude I know)
My final thought is make a sphere that has one entrance make it of something that doesn't rust and make it large/strong enough to withstand the pressure and instead focus on the propulsion tech and up with a gravity drive or something that can do two thing one : alter the gravity of the object that holds the drive (reducing the pressure on the sphere ) and two: work in almost any "atmosphere"
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The real key to moving underwater is the static pressure increases at a very rapid rate as you go deeper into the water. On Earth the increase is one bar for every 10 m of depth. It is a bit unclear how the pressure increases with "depth" in your universe, but using this assumption, submersible spacecraft would have to be immensely strong in order to reach greater depths (assuming there is anything interesting or useful "at depth" in your universe).
In terms of how this would affect spacecraft, you are essentially building nuclear submarines for use in this "ocean". A warship would probably resemble a nuclear attack submarine like the USS Virginia or the Indian INS Arihant, being a compact cylinder with hydrodynamic ends and some sort of propulsion system. The requirement for a "sail" might not be there, since it is unclear to me if the submarine/spaceship ever "surfaces" in the alternate universe. Cargo ships would be much larger, resembling "Boomers" like the USS Ohio class or Russian Typhoon class boats.
Spacecraft, OTOH, are not constrained to resist pressure from external forces, and can be built much more lightly. Deep space craft generally only have to contain an interior pressure of one bar against the external vacuum, and even atmospheric craft like a shuttle are not subject to crushing pressure like a submarine. In a realistic setting, they also need massive radiating surfaces to reject waste heat, and since they would be subject to the tyranny of the rocket equation, every gram counts. They will be built as lightly as possible in order to maximize deltaV and minimize the use of fuel and reaction mass. The only exceptions would be an ORION nuclear else drive or something that is propelled by an external energy source like a laser beam.
The best way to contrast the two might be to think of an airship and a submarine. The airship is analogous to the spaceship; lightly built to operate in the atmosphere, while the submarine is strongly built to resist the pressure of the water. Both vehicles use buoyancy to remain "afloat" in their medium, and both superficially resemble each other for aerodynamic and hydrodynamic reasons, but neither could operate in the medium of the other.
The best possible solution would be to have some sort of trans shipment point at the interface between the two universes, and have separate ships for each set of conditions.
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**Aircraft**
It seems to me that craft in your universe will simply fly, as this is quicker than sailing and places less stress on the craft. Its possible some more bulky items might be transported by bulk freighter, but assuming that your spacecraft travel using some sort of energy drive rather than reactive mass, and have energy shields to protect themselves from space debris and high speed particles, and are capable of atmospheric flight - it's simpler to just fly. As all of these are pretty common sci-fi tropes and clichés, and it's harder to explain reaction craft and energy shields unless you go properly hard-scifi, this is the route I would go down. The only exception for this could conceivably be if your craft are not capable of flight, in which case you're probably looking at bulk cargo being transported and more important items and passengers being transported "locally" to aqua by air.
To give you some idea, the Lockheed SR-71 Blackbird holds the official Air Speed Record for a manned airbreathing jet aircraft with a speed of 3,530 km/h (2,193mph) set in the 70's.[[source]](https://en.wikipedia.org/wiki/Flight_airspeed_record) The current *surface* water-speed record is 511 km/h (318mph) also set in the 70's [Source](https://en.wikipedia.org/wiki/Water_speed_record). Underwater, U.S. Navy and GE are jointly developing the Underwater Express, an undersea transport capable of controllable speeds up to 100 knots (185 km/h, 115mph) through supercavitation, and underwater weapons systems taking advantage of the supercavitation concept are already in existence, with a rumoured top speed of around 800 knots (1481 km/h, 920 mph) for the German "Barracuda" anti-torpedo missile.[[Source]](https://en.wikipedia.org/wiki/Underwater_speed_record)
Essentially, water is hard to move through - much harder than air to the point where underwater, the fastest objects actually are more like missiles flying through their own little pocket of air than torpedo's [[source]](https://en.wikipedia.org/wiki/Supercavitation). You're going to have real trouble getting and maintaining anywhere close to what you might imagine to be space-travel worthy speeds under- or over-water.
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After reading a couple dozen entries about rogue planets and their implications (for those unaware, a rogue planet is a planetary mass that has been separated from the star by gravitational instability or otherwise forceful means).
If a planet was geologically active underneath the surface, enough so that the surface of the planet was heated above freezing temperature, would it be viable for life to evolve on the planet? The planet would, obviously, be bombarded periodically by meteorites of various sizes, and the surface must be exceedingly cold. But, as theorized with a few moons in our Solar System, wouldn't underlying water be able to be heated to the point where life is possible?
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Yes! The more we discover on life, the more we realize it'll evolve anywhere it can. Europa, moon of Jupiter, could likely support life using heat that's generated from the gravitational interactions of it and Jupiter.
However it is questionable how far this life could make it as you require some stability to have anything beyond basic cells start to evolve. The universe is a messy place and this planet could easily be under constant bombardment by asteroids. But more over, our sun supports what is known as the Heliosphere. Just like Earth, the sun supports a magnetic field as it travels through space that deflects much of what would kill life on Earth...cosmic rays, solar winds, and all sorts that would have a catastrophic effect had it interacted with any life form. Outside of the Heliosphere in intergalactic space, we can see things like protons travelling 99.99999% the speed of light (only way we can detect this is they occasionally shoot neutrons at us). This is an atom with the energy of a baseball going 100mph...if that strikes a cell, it ain't surviving. What exactly is protecting this rogue planet from the harshness of stellar weather?
So the answer to your question ultimately becomes 'define life'. If you are looking for single celled organisms, it's gotten to the point that it's hard to deny that they would be there. Extremophiles thrive on Earth in some of the harshest conditions possible. We can find life on Earth capable of repairing it's own DNA, which would likely be an essential component of life on this rogue planet. So the possibility is there...However if you're talking some relatively advanced life, even creatures like small fish, then this life is going to have to overcome some incredible odds (like surviving space weather) in order to survive.
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The moons in our solar system are around large gas giants and most of their internal heat is being generated by tidal pressures from the gravity of the gas giants they are orbiting. Your rogue could have a similar setup if it is part of a rogue system of moons around a large rogue gas giant.
The other sources of internal heat in planets is the residual energy from formation and the decay of radioactive elements. The formation energy comes from all the kinetic energy of the coalescing asteroids and other bodies that came together to form the planet and could be quite high. Some of the elements in the core are also radioactive and their decay releases energy also providing heat. Your planet could always tweak these parameters to increase your rogue planets heat budget.
<https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget>
As the Earth's internal heat has been going for 4+ billion years this should easily provide enough time for life to evolve.
For Earth analogues look at the life present around deep sea thermal vents.
<https://en.wikipedia.org/wiki/Hydrothermal_vent#Biological_communities>
Also if this planet has left its star and gone rogue it is very unlikely to suffer asteroid impacts. Space is big and empty away from stars.
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This is quite feasible. The key point can be found in the Wikipedia entry on [rogue planets](https://en.wikipedia.org/wiki/Rogue_planet)
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> Interstellar planets generate little heat nor are they heated by a star. In 1998, David J. Stevenson theorized that some planet-sized objects adrift in the vast expanses of cold interstellar space could possibly sustain a thick atmosphere that would not freeze out. He proposes that atmospheres are preserved by the pressure-induced far-infrared radiation opacity of a thick hydrogen-containing atmosphere.
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If the rogue planet is geologically active, this is something the OP specified, then there is a good chance that a biosphere could develop. Most so in the light of what is known about the extreme conditions where life can survive.
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Theoretically it should be ok so long as heat generated by the planet itself was not escaping at too high a rate.
**However**
Due to the lack of any kind of inbound energy to substitute for a star, photosynthesis would be impossible, therefore an ecological biosphere would be unsustainable.
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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've mentioned in earlier posts that it will be much cheaper to build immense space-based observatory instruments than to even come close to launching an interstellar expedition.
There are several figures of merit including total light gathering area and separation of light gathering points.
Imagine nanotechnology that "grows" a module from material in the asteroid belt, and then dispatches it out beyond the dust of the inner solar system. The technology can record the visible and infrared light waveforms in sufficient resolution to combine them from different modules and synthesize an image from a mirror the size of the separation. (This kind of recording delayed synthesis has long been a thing for radio frequency observation.)
How small of details on exoplanets could be seen? Is there a diminishing return when making the distributed modules ever bigger, or can resolution go up indefinitely?
Does the light gathering capacity matter as well? What is the right order of magnitude to match the magnification? Off hand, I expect the target to be lit as bright as daylight, just very tiny; does the total light gathered change with the apparent target size?
Today, a star-shield is needed to prevent a planet from being washed out from the nearby star. Would a narrow enough field of view make that simply unnecessary, or is there some optical effects related to absolute separation of the targets?
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## summary
1. How small of details on exoplanets could be seen? **math: separation between modules, individual module size, and resolving power; resolving power to exoplanet distance and ground feature size.**
2. Is there a diminishing return when making the distributed modules ever bigger, or can resolution go up indefinitely?
3. What is the relationship between light gathering capability, brightness of the image, and size of the imaged object?
4. Use with star shield?
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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.
There's a couple of different questions in there, and I'm going to take a stab at some of them.
First, you seem to be generally familiar with [aperture synthesis](https://en.wikipedia.org/wiki/Aperture_synthesis), as you imply it in one of your questions. That basically means if you have a bunch of comparatively small data sources (telescopes) you can merge them into one image as if you had on telescope the diameter of the distance between any two of them.
This gives you a much better angular resolution than you might expect. Unfortunately, you seem to be correct about the diminishing returns aspect. Take a look at [this](https://en.wikipedia.org/wiki/File:Diffraction_limit_diameter_vs_angular_resolution.svg), which graphs total diameter of a telescope against its angular resolution for given wavelengths of light. It's on a log scale, and only goes up to 10,000 km. On an astronomic scale, that's roughly the size of the earth.
This introduces quite a problem. Humans *already* do something like this by taking advantage of the Earth's annual trip around the sun. By taking measurements six months apart (from anywhere on Earth), you get an effective dish size of around 300 million kilometers. And as it turns out, with a dish that large the closest star is still only 0.772 arc-seconds across. Fortunately, that seems to be within a reasonable range (that is, appears on) at least one axis of the chart I linked earlier.
My conclusion is either I'm really misunderstanding something here1, or you should be able to get a reasonable picture (in some wavelength of light) by creating a satellite cloud between Earth and Mars. If you have to build it bigger, that should actually help.
As a side note, when I started researching this question, I expected to need a telescope the size of the solar system or larger, implying the limit to the size of the telescope is actually how long you can keep the satellite powered (shout out to the Voyagers!) before they stop giving you data back. I was pleasantly disappointed on that.
1Some math would really help here for verification.
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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 warms the cockles of my heart to find someone else who realised space-based observatories are much, much cheaper than interstellar expeditions. They would gather the same or possibly more information than our first generation of interstellar probes. Perhaps, hypertechnological telescopes are one solution to the Fermi paradox. Aliens aren't visiting us or are wandering up and down the galaxy because their telescopes do all that work for them.
Aperture synthesis is definitely one way to go. Both optical and radio telescopes can ramp up the size to truly heroic sizes. However, there is an alternative astronomical observatory that will yield a cornucopia of information about so much of the galaxy. Basically it exploits the gravitational lens formed by the Sun and this is located outside of the solar system. The proposed FOCAL mission doesn't need new technology. Although it is way beyond the space technology because the extremely long mission time. The Sun's gravitational lens is roughly 550 AU away. That's a cool 82,500,000,00 distant. More information can be found at the following links.
<http://www.centauri-dreams.org/?p=785>
<https://en.wikipedia.org/wiki/FOCAL_(spacecraft)>
<http://www.newyorker.com/tech/elements/the-seventy-billion-mile-telescope>
The FOCAL mission can involve both optical and radio telescopes. Radio telescopes are capable of gathering information which is orders of magnitude more information than in any photograph. It's possible to imagine a future ring of FOCAL observatories strung around the solar system studying the galaxy in fine detail. They would still be cheaper than sending just one relativistic starship.
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It’s Earth, the modern day…and in the out there, there is a fight going on.
Two vast space-empires duel for survival, locked in hateful combat. Clashes of fleets and individual spaceships are the most common method of conflict; controlling the ultimate “high-ground” of space an almost guaranteed success for any battle on a different field.
Ships of all (reasonable) sizes combat one another, from small fighter sized craft to carriers and battleships the size of skyscrapers. The weapons they commonly use against one another would not be unfamiliar to modern humanity, merely advances on what we use now; lasers, railguns, and nuclear missiles, along with a smattering of more exotic methods of inviting entropy upon an enemy.
For some reason they are fighting one another in or around the Sol system. Perhaps they were drawn here by weird radio signals that they assumed to have been from an enemy’s base. Each empire sends in expeditionary forces to investigate and they lock in combat when they “warp in” on top of one another perhaps.
How “close” do they have to fight to Earth, with the above ships and weapons, to be “noticed”? Would they be observed duking it out around Pluto? Or would they be missed if they were tossing nukes around between Earth and the Moon?
I know random chance is really everything, but discounting that, I’m after the limits of where it is reasonable to place a couple of Type I civilization space-fleets doing their best to end each other somewhere in the solar-system where they will be observed. We have good number of things pointed at space, but they all cover just a very small portion of it, and I’ve only heard of the idea of actively looking for asteroids more than a relatively short distance out. I have no clue how close something that’s actively emitting energy has to get before it is “seen”.
Some assumptions;
1. it happens “close" enough that more than one telescope picks it up; it should be an obvious enough event that it couldn’t/wouldn’t be covered up.
2. They get here by a method of an “effective FTL”, wormholes or some other technique that doesn’t violate reality, but they’ve figured out how to be moderately stealthy about it.
3. They use technology that is “explainable” (outside wormholes), no hand-waving; if it’s not possible they don’t have it. Their FTL method isn’t well suited for weapons or real-space communications. If it’s reasonable for humans in the next 100 or so years, they probably do have it.
4. No particular assumptions on their tactical and strategic decisions beyond whatever will take them to the location that they can/will be discovered.
5. Also; while they may or may not pointing their weapons specifically *at* earth on occasion, its not about the speed of light; it's about if we would notice them and look back along the trajectory of whatever and see where and what it was coming from.
The general idea is that people witness and know that there is a fight going on out there; not particularly the details, but we should be able to see the “fight” and observe the debris afterward.
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They will easily be detected, IF we know where to look. The heat output of a space ship can be easily detected, especially if they are maneuvering using any type of rocket or are using radiators to dump heat produced from weapon firing.
Here is a portion of a discussion about space detection (<https://groups.google.com/forum/#!topic/rec.arts.sf.science/-E6r2F8rgnQ%5B151-175%5D>)
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> As for detection range, such a system could spot a single Space
> Shuttle attitude control thruster firing at a range of fifteen million
> kilometers. Light up the whole package, main engines and SRBs, and the
> detection range jumps to twenty *billion* kilometers.
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He is describing using a 2 meter IR telescope, similar to many on Earth. Pluto is well within 20 billion KM from Earth, so assuming we knew to point a 2 meter IR telescope at Pluto, we could detect the heat from all those ships maneuvering and venting (assuming they have to do that).
If they are cooking off nukes we could also detect the gamma rays and x-rays. We have lots of sensors and telescopes set up to detect and track these things, so that will probably be the biggest giveaway of a battle. Powerful visible light telescopes could probably catch explosions as well, though perhaps not as far away as Pluto (maybe the Hubble, which has 10 times the resolution of ground based visible light telescopes).
So the main problem is knowing where to look at all. Radio telescopes are not omnidirectional so radio transmissions and energy broadcasts won't just be picked up automatically. So you must either have the battle occur close enough to earth that we can see it with the naked eye to clue us in (which probably means lunar orbit or closer) or it will have to happen "co-incidentally" were we have a telescope pointed. So chose a place we often observe, like Jupiter.
I doubt lasers and such could be detected around pluto, as they would have to be fired directly at us and be EXTREMELY powerful.
As for seeing the ships themselves out by Pluto, no way unless they are simply MASSIVE. The Hubble has a 0.1 arcsecond of resolution, IIRC, and can barely observe Charon (600 km wide). 0.1 arcsecond is 72 km at 1 AU, and Pluto is 30-50 AU away from Earth, so do the math. Your only hope is that New Horizons happens to be passing by and we can task it to take a look, though I think receiving the images would take quite a while.
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I would go for a **No!** for that question, because your premises are pretty unlikely.
But as said countless times before: space is vast. Only if your combatants are using a technology that will make them appear within each others weapon range they will start shooting at each other (or, if they are good scouts, break up contact with the enemy and run away to report enemy contact).
I remember only a few sci-fi technologies that will make ftl-ships appear at choke-points - if you just warp in the general direction of your target sun it would be possible for the two factions to appear at the same second at the most opposite places possible without ever noticing each other. Only gate jumps would lead to a shared place of appearance, or something that joints on some Lagrangian points (like the node drive from Sword Of The Stars).
Why do I write down all of this? Because except for the ftl - techniques mentioned above there will be no battle at all. Even when they are able to detect each other appearing (well, its more likely that these who appear first will notice these who appear last but not the other way round), it would be plain dumb to start a battle with someone you need to approach for a day or even longer in a way that its highly notable by your enemy to get even at maximum weapons firing range. Just write down a contact report and get the hell out of there. After all you do not send out an Aircraft Carrier to scout a remote island but deploy a plane that will run for its life if enemies had been spotted. After the contact report had been made, more decisions will be made...
So they will appear, check their sensors and make their way towards that strange source of strange radio noise. At a given point it will become clear that this is caused by "puny humans", so both of them will leave without even knowing the other side is around. Maybe. Or they notice the other side is here too and start thinking that they try to ally with these puny humans. in that case... well, everyone on earth would notice if they are going do some preventative striking.
Back to topic - so beyond all strategic, operational and tactical questions... when one thing did led to another and two groups actually start firing at each other... that would be an event that takes what? Ten minutes? A sudden radio burst from the general direction of Aquarius? Well, we do have them already. So at this point I would join the general opinion that states that you need to look at the right direction at the perfect moment - all that is so far away that its already over when signals arriving here will be impossible to get tracked down.
Its like you are sitting in your room, hearing a firework out there (if you hear it after all) and go outside, but sadly its all over already. If it was pretty close to you, you might spot a flash of light, maybe see the guys who did fire it after all, smell the powder. If it was some kilometers away you come out and notice... nothing. When you start running circles you may find the empty batteries somewhere (good luck with that). And not try to find a firework-battery in a neighborhood that has a diameter of a million kilometer.
If you can see fusion fire lighting up in high earth orbit and your satellite receiver stops receiving and litters up earth would notice, but as soon as its done in a distance of a light minute, just a bunch of hard to track signals will be received. If someone looks there after the action and can resolve junks of spaceships with whatever he is looking there its likely too to reconstruct what did happen, but in most cases... well, what was that? After all, dead spaceships will look like another uninteresting asteroid... at least as long as no probe tries to land on it.
So if you want them to do a spectacle have them brawl in high to low earth orbit. Just hide one side at the dark side of the moon while the others are approaching and place a officer in command with a nervous (or happy) trigger finger. Everything else? Incredible luck needed.
For the finish, I remember a radio spot here that is used to show how good radio commercials can be: the marsrover is calling home, telling us, that he is bored with red stones eeeevery day and more red stones and even more and please pick me up home. But wait, someone is approaching.... silence.
So let these guys pickup or destroy an earth bound probe and let the other side going for that "evidence" they just collected - that would be perfect, because half of all space agencies on earth would try to reestablish communication with that lost probe and are looking with their finest equipment in the right direction at the right moment.
Faerwell...
EDiT: Well, if you want the most greatest audience possible, place your point of storytelling some time in future, let the whole world (or at least these who own a TV or a PC) witness the brave mars explorer crew placing their first foot at Mars. Just in the moment the mission commander places himself and his crew in front of a UN-Flag to make a selfie-stick supported group selfie, a unknown ship approaches and takes these guys in custody to find out what part they do play in their interstellar war - on livestream.
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**This is quite simple**
The speed of light is 299792458 meters a second or 186282 miles a second. For example it takes the light 9 minutes to travel from the sun to Earth. Even if I have a super powerful telescope, I still need to wait for the speed of light to send the signals. So depending on how quickly you want the battle to be seen from earth your distance follows this. For example if the space fight occurs around Alpha centauri A it will only be detectable from earth 4.3 years after it happens and this assumes their lasers are extremely bright, if the lasers are as bright as lightbulbs or lazer pointers, it is unlikely we will ever see it.
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Let me quantify the *notice* part, given (in other answers) that ordinary and common instruments can detect your postulated actions.
With programs like [LSST](https://en.wikipedia.org/wiki/Large_Synoptic_Survey_Telescope), it will be noticed within a week if it's on the night side of the planet.
With terrestrial instruments, any action going on out there on the far side of the sun (that is, visible in the daytine sky) will be washed out by the sky so it will take a few months before the event is visible against the *night* sky.
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We have a number of radio telescopes that scan the sky so if the fleets are emitting radio signals there is a good chance those will be picked up.
If they are using nuclear weapons widely the flashes will probably be picked up too.
The distance does not make that much difference, it won't be a problem to pick those up from the edge of the solar system.
Radio waves are probably the better option though. New Horizons for example is communicating with Earth through the DSN on regular bases, so if loud radio wave sources appear in the vicinity of Pluto it will detected fairly quickly.
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Something the size of a [small] planet is only just barely visible at the range of Pluto, so unless they have REALLY big ships, they probably won't be visibly. Nukes are just a brief, bright, flash, unless you know what you're looking for, you may see it and discount it as a closer in meteoroid or some such.
Now, if someone was using a radio telescope in that direction, they might detect enough interesting EM noise to suggest that optical telescopes focus out there, after figuring out where the signals are coming from.
Still you aren't going to see much except flashes.
Now if there were in as close as Mars, that'd be a different story.
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We noticed when the aurora went haywire. The sky was lit from horizon to horizon with brilliant green dancing fire. That first night, the whole world watched in awe of the beauty. As the days went by and the aurora only intensified, I watched as awe was replaced by curiosity, and curiosity replaced by fear.
After two weeks of uninterrupted aurora, we found it. Or should I say we found "Them."
Normally aurora is caused by charged particles from the sun, but evidently solar flares aren't the only way to create a massive stream of charged particles....
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This is an interesting question that was answered by the hilarious question of, "how many flashlights would it take to show up on the moon".
<https://what-if.xkcd.com/13/>
While this doesn't answer your specific question, it lets you know the sheer magnitude of light needing to be put out to show up as small scale objects.
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# Yes. And no.
We regularly detect fast moving, large asteroids, and their courses are tracked. So far, observers around the world have found and tracked more than 10,000 near-Earth objects. Most are a about 140m (I don't have a source for this). Rosetta was identified and tracked from near the distance Jupiter is from us, but it's pretty large.
One of our observers would see anomolous moving 'asteroids' and get very curious about it. But we can't even see lunar equipment with any detail. So this would require the time and energy to go near this space war, which likely would be over or moved long before we got there.
So we could see that there's something artificial moving around, but it would be very difficult to find out what was going on. Complicated by trying to get a trajectory if dots of light are moving long distances.
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Spotting the fight is going to be somewhere on unlikely end of a scale of probability.
**Lasers** we won't see unless they miss their target and directly hit a telescope. A good laser only projects energy along the beam, unless it hits something (or you) you never know its there.
**Railguns** we won't see at all.
**Nukes** we won't see unless a radio telescope is pointing the right way at the right time, and even then we're on a speed of light delay. Even if we see something it may well not be until everyone has long since cleared the area. One won't be enough to extrapolate information from, we'd need to see a cluster before we started considering that option.
Following the line of thought that says only nukes *could* be seen we need to work out how far away we could spot them from and how many we'd need to see before we worked out what was going on.
I'm leaning towards it being highly unlikely we'd see the brief speck in the vast darkness that would be a space battle.
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Due to an evolutionary arms race , highly intelligent dire wolves evolved on my world. Their vocal cords have developed to produce beyond human ranges of sound , and have become more social , gathering in packs over 300 strong. They have even developed a complex language , and have naming systems for different members of their species. They now have all of the attributes that they need to develop a civilization save for one , prehensile limbs.
My question is : is any sort of technological advancement ( even that of tool use ) possible in a species with no prehensile limbs?
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When you say "prehensile limbs," does that mean you are excluding all appendages that could easily substitute for human-like hands (e.g. monkey tails, bird talons, etc)? I am going to assume yes, because otherwise your question would not make any sense.
If the species itself lacks the fine manipulation necessary to use tools, then they could not develop the skill to build and use tools. At least not on an *individual* basis.
If they have the ability to hold objects, such as with a pair of jaws, then they could potentially figure out how to work together to build and use tools to compensate for their individual lack of prehensile appendages. Each "pack" (for lack of a better term) would act as a pair of hands. As a result, their society would probably be much, much more collectivist than our own because they are so dependent on one another to accomplish tasks that would be trivial for a human being. At the extreme end individual packs might develop a distributed gestalt consciousness a la the Tines in Vernor Vinge's *A Fire Upon the Deep*.
Or they might domesticate another species that does have prehensile limbs. In which case they might develop along lines where much of their energy is devoted to developing means to better control and direct their laborers, potentially engaging in much more extreme forms of selective breeding than humans ever have. Since all labor would be done by their "pets" (for lack of a better word, since slavery doesn't really apply), then they themselves might atrophy physically in order to devote more processing power to manipulating their pets.
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The first step to developing technology of any kind would be starting to make use of tools. Your dire wolves would need to be in a situation where they develop tool use for increased biological fitness. (I know of examples of monkeys of all kinds and crows who developed tool use, but none of wolves. What kind of tools would wolves need in the wild?).
Once you've got tool use established, you can start extrapolating the resulting technology from that. (i.e.: depends on what kind of tools they use). Most likely, they will never get much beyond very basic tool use since they both lack the dexterity to create finely crafted things, and the need for them since nature gifted them with plenty of natural weaponry and a warm coat. They could have fire (or at least have the ability to not let a burning fire go out and feed it with more wood), but pottery? I doubt it. Unless their forepaws evolve to give at least a bit better dexterity than a typical wolf paw.
Stone tools like knives? What would they need them since their teeth are sharp enough and they can defend themselves well enough? and anyway, how would they get them shaped?
What they might have toolwise is something to make food storage better. Perhaps they know that burying meat in salt-rich soil preserves it better than in regular soil? Then again, wolves are also capable of eating pretty spoiled meat, so...
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Let's take a broad look at the history of technology in humanity and apply it to wolves, and how they might get there:
# Hunter-gatherer
Current state, wolves on earth are reputably adept at this.
## Agriculture
Agriculture is the first step towards any civilization, as a surplus of food is necessary to create a class of non-food-producing specialists capable of handling needs like governance, health care, crafting tools and so on. Assuming climate conditions allow for agriculture (predictable seasons, no ice ages etc.), hyper-intelligent wolves capable of complex communication (among each other at least) shouldn't have too much trouble coordinating each other by corralling/enslaving other animals into doing their work for them. Smaller animals like squirrels can be used to plant seeds and larger animals like oxen can till the soil and carry water.
# Industrialization
Ok, this is where things get tricky. To industrialize even vaguely like the way humans did, the wolves will need to A: extract and refine new sources of energy, and B: use those new energy sources to drive non-muscle-based machinery, which decouples the production of food from the production of mechanical energy (since mechanized farming is far more efficient than using muscle power).
First, let's look at resources. It is worth noting that in America's 19th century, the dominant source of energy was wood, not coal. Certain creatures from Earth, like beavers, can create dams, so perhaps a degree of hydropower is in order (but keep in mind that hydro is BY FAR the MOST DANGEROUS form of energy creation because dam failures can be catastrophic in ways a nuclear meltdown can barely hold a gamma wave to). So let's say the enslavement-of-other-creatures method works well enough here for basic tasks like cutting down trees and carrying them at the very least.
Now for mechanical energy. Again, this is a rough one since wolves will be limited in their tools and their ability to create more tools. This might end up being the bottleneck for productivity, since if the limit to dexterity is a jaw and a paw, it will take a significant amount of wolves to craft any kind of tool, let alone a steam engine. But let's consider something else...
# Information Age
What if the wolves leapfrog the steampunk era and go straight into cyberpunk? After all, the principles and physics of computing are the same no matter where you are, so if the wolves can reliably generate electricity and make some kind of Minecraft-like basic computer, they ought to be able to shrink it over further generations. The further they advance in their technologies, the more possible it may be that they could create machines that can, in turn, create more tools and machines that are useful to them, perhaps in the style of a 3D printer.
So there you have it. A bit glossed-over, but a somewhat reasonable path from hunter-gatherer to information age for any land-dwelling social species capable of withstanding elements and communicating complex concepts to each other.
\*Physics work a bit differently underwater, so that probably explains why dolphins haven't conquered us yet.
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Tool use certainly, [corvids are particularly good at this](http://users.ox.ac.uk/~kgroup/tools/introduction.shtml).
Whether they could get further technological advancement is questionable, from there on it's dependent on control of fire which is hard without a prehensile limb. You're limited to "found items", or found items with minor modification.
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I'd like to run with the idea of using "pets"and expand upon it, based on a few observations of wolves and dogs.
I've seen a study on TV where a piece of meat was placed in an inaccessible location, under the metal-mesh crate.
The (tame/socialized) wolf tried to get it, persistently, without success.
The dog noted the situation and asked his human to take care of it. The dog put no wasted effort into digging or biting the metal, but *clearly* got the man's attention, and alternated eye contact between the man and the goal, to communicate that he was wanted at that location.
At home, I recall a new puppy decided to purposfully toss his ball under a hutch where he couldn't reach it, to make Dad go down on the floor and get it for him. Which was the real goal: go get Dad's head down to floor level.
Dogs have evolved to rely on humans to get their goals met, and even as infants will instinctively manipulate and exploit the known behavior of other lifeforms in their environment.
It's thought that wolves domesticated themselves, finding a niche among primitive humans.
Well, what if wolves (as in your plot) found other species that had resources they could exploit, but happened to not be intelligent? Some *other* animal that had a social nature and produced communal garbage piles and were omnivorous. Eventually the wolves cooperated in hunting and gathering, and formed combined packs which were more capable than either alone.
The wolves quickly evolved to make use of the other animals as tools, instictively understanding that *they* do things we can't, and can be used on purpose. Which is exactly what wolves did in real life.
The other creatures, weasles or squirrels or whatever, quickly evolved to rely on the wolves to fill certain roles, including making decisions. That is, what wolves did to men in this department, the weasles did to the smart wolves. So thus coukd really happen: they adapt as it's advantageous to let the intelligent leader (of a different species) make tactical decisions and engage in planning.
Perhaps other animals join the mixed pack over time. Or, now on the road to civilization, the wolves domesticate other species.
The real question is how well can the wolves control the "hands" of the symbiotes? If it's just high-level management of instictive or trained tasks (like how a human directs a canine sheapard), it would be hard to made unique detailed motions.
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In the Star Trek: Deep Space Nine episode The Die is Cast. A planetary bombardment scene occured where 17 shots was stated to have destroyed 30% of a planet's crust. Now obviously that's a HUGE amount of firepower, but it's not unrealistic for Star Trek as since the pilot episode of the original series they stated they had enough firepower to blast a continent.
So what kind of firepower are we talking about here?
Specifically if the entire crust were destroyed right down to the mantle. As in what kind of energy levels are we talking about (preferably in tnt equivalent) would be necessary to destroy completely or severely extrude the crust of 30% of a planet's surface area? What about the entire planet?
To make things easier lets just assume values for Earth.
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The always helpful [Atomic rockets Boom Table](http://www.projectrho.com/public_html/rocket/usefultables.php) has the following information for us:
>
> 6.6 × 1026 J, 158 Pt: Energy required to heat all the oceans of Terra to boiling
>
>
> 3.2 × 1026 J, 77 Pt: Energy required blow off Terra's atmosphere into space
>
>
> 7.0 × 1027 J, 2 Et: Energy required to vaporize all the oceans of Terra and dehydrate the crust
>
>
> 2.9 × 1028 J, 7 Et: Energy required to melt the (dry) crust of Terra
>
>
> 2.1 × 1029 J, 50 Et: Earth's rotational energy
>
>
> 1.5 × 1030 J, 359 Et: Energy required blow off Terra's crust into space
>
>
>
(remember, 1 Pt = 1 000 000 gigatons; 1 Et = 1 000 000 000 gigatons)
Just to put this into perspective, we should consider:
>
> 5.5 × 1024 J, 1 Pt: total energy from the Sun that strikes the face of the Earth each year
>
>
> 3.9 × 1026 J, 92 Pt: total energy output of the Sun each second (bolometric luminosity)
>
>
>
So to seriously destroy a large part of the planet's crust you would need to somehow generate and deploy a large fraction of the energy of a yellow dwarf star.
In real terms, it seems very unlikely that a ship would be able to do anything like this on its own. The only plausible mechanism would be the ship opens a wormhole to the closest star and directs the star's energy against the planet's surface or better still somewhere under the crust. Just don't stand too close....
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Is it possible that a complex humanoid creature to somehow still use [Mitosis](https://en.wikipedia.org/wiki/Mitosis) as a method for reproduction, and if so, what would it look like?
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While BlindKungFuMaster is sort of correct, I don't think that is what you had in mind.
You want a humanoid body that splits in half, and then the resulting two forms are viable individuals.
The problem with this is that splitting a human in half makes us non-functional, so first you need to duplicate all the vital organs. But that's still not enough, how do you do the split? The most likely way would be a vertical split from the top of the head to the crotch, this has the least "surface area" to create and reseal.
So this would probably start with the growth of vestigial limbs at the front and back of the body, these would grow gradually, becoming more and more viable. At the same time internally the vital organs are duplicating and splitting, until eventually you have two hearts, the two lobes of the lung have separated and are starting to form a new pair.
The head would start to expand outwards and new brain cells fill in as memories are copied between the two halves as they gradually become more and more separate.
After a few months you have a body with two heads, and extra limbs front and back. The two systems would continue to separate and new skin grow in to cover them all until eventually they fall completely apart and rise as two separate individuals. They then have to argue over who gets which possessions.
During early stages they would be able to function as normal. Once the separation grew advanced enough this would become harder and the last few weeks would involve bed rest most likely. The splitting and reforming of the brain would most likely cause confusion and mood swings, and the two resulting people while being genetically identical would not have fully identical memories or personalities.
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Doubling every part of the body and then splitting into two separate persons strikes me as unrealistic. Humans (or any creature really) need a long time to build up so much tissue, after all this isn't just filling fat cells until you have added 50, 60 kilos. So this would basically amount to a several year pregnancy in which you add another hundred percent of your body weight!
Instead I would consider something akin to the [power of a planaria](https://www.mpg.de/8244494/flatworms-regeneration). These flatworms can be cut into up to 50 pieces and every single piece turns into a fully functional worm again. They do this by turning cells back into stem cells and then basically rearranging the complete layout of the little part until a small but viable worm is recreated.
For humanoids this sounds farfetched, but less so if your humanoids have organs that are decentralised and redundant. In that case they might just drop an arm and wait until it turns into a baby …
Let's say if a body part is dropped or cut from the body the skin secretes a kind of cocoon in which the transformation into a baby occurs. That would be similar to the [metamorphosis of an insect](https://en.wikipedia.org/wiki/Metamorphosis), which also often involves a switch to a completely new body layout.
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Mitosis is a process specific to single-celled organisms. However, there are some multicellular animals, such as planaria and starfish, that are capable of breaking into fragments and regenerating into multiple individuals. Some starfish will fragment proactively as their main means of reproduction.
The main reason why this ability is absent in 'higher' animals is due to the complexity of the central nervous system. Vertebrates have a highly regulated growth pattern with very specific stages from zygote to adult that does not work well unless it develops from start to finish. While some vertebrates have limited regenerative abilities, we cannot grow a whole central nervous system unless we start from scratch.
If a vertebrate were to 'split' in order to reproduce, it would need to grow a new body as a 'bud', starting from a lump of cells and passing through the standard growth stages before breaking off of the parent body. Of course, this would be a lot more inconvenient than just growing a clone *inside* the body... which is just parthenogenesis.
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I asked a somewhat related question in May 2015: [What needs to be different in order for a parthenogenetically reproducing species to evolve sentience?](https://worldbuilding.stackexchange.com/questions/15530/what-needs-to-be-different-in-order-for-a-parthenogenetically-reproducing-specie)
The answers might be useful to you, although they focus on the conditions in which asexual reproduction might dominate rather than on what the mechanics would be. As BlindKungFuMaster has said above there is no obvious reason why the humanoid shape, or sentience, should be a barrier to it occurring. It is rare but not unknown in large animals. It sometimes occurs in [komodo dragons](http://www.livescience.com/9460-female-komodo-dragon-virgin-births.html) and turkeys.
Note that parthenogenesis can occur [with or without mitosis](https://en.wikipedia.org/wiki/Parthenogenesis#Types_and_mechanisms), though I confess I don't really understand what "Parthenogenesis can occur without meiosis through mitotic oogenesis" means.
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Well, I'm assuming you mean like a bacteria, instead of making gametes through mitosis. The main problem would be, well, the complex part. The more complex you are, the more genetic information you need to make yourself, meaning higher risk of screw ups during the division process, a.k.a cancer, which is also why we don't regenerate lost limbs. However, if your humanoid has a way to never make such mistakes and could multiply its cells at a much faster rate, I'm assuming preparing would need to be the main part. Just like cells shut down their usual metabolism to grow in size and duplicate everything, I'd assume your being would enter a process like preparing for hibernation. After that, I'm unsure. Perhaps it could start making an external "sack" with a lot of stem cells, having it mature into adulthood at a fast pace, while remaining linked to it on the process, acting as the nutrient reserve part of an egg, but without the shell. Or perhaps it could enter a stage where it temporarily become Symbian twin, starting by slowly splitting its head in half like so:
!
After that it would duplicate its spine and slowly continue the fission towards the end. But in both cases, I'd assume it enters a lethargic state, as mitosis is already a costly process for a single cell, let alone an entire organism. Hope it helped
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Revelation Jerusalem is **the** golden city, the true envy of the world. Tradition has it that it's bathed in eternal light, that the unworthy are struck down on its doorstep, and that a sense of holiness pervades the place. So much for tradition. More importantly for our purposes, it's really a *golden* city. Sounds expensive, but just how expensive?
Required WB input: **order of magnitude estimate of cost**. I'd prefer the estimate in 2016 US Dollars or as a ratio to US Annual GDP at $17.4 trillion.
Here are the salient features we are concerned with:
* *The Sea of Crystal* -- A reflecting pool, roughly the size of the [Reflecting Pool](https://en.wikipedia.org/wiki/Lincoln_Memorial_Reflecting_Pool) (618 m x 51m). Must be covered throughout in inlaid emerald and topaz.
[](https://i.stack.imgur.com/KjeHa.png)
* *The Statue of the God-Emperor on a Throne*, roughly similar in size with the [Statue of Zeus at Olympia](https://en.wikipedia.org/wiki/Statue_of_Zeus_at_Olympia), about 13 m tall. (Can be) hollow or non-gold support structure, but both statue and throne at least 1" thick high quality gold, encrusted with precious gems, like thus:
[](https://i.stack.imgur.com/aja1N.png)
* *The Twelve Gates*, studded in pearls spaced such that they blend seamlessly into each other (or a single pearly slab if possible), each roughly the size of the [Ishtar gate](https://en.wikipedia.org/wiki/Ishtar_Gate), looks about 5m x 12m.
[](https://i.stack.imgur.com/0CQi5.png)
* *The Golden City*: All buildings covered in gold foil (approximately 1000 buildings, average 400 sq. m of roof each)
[](https://i.stack.imgur.com/gY3IO.png)
* *Shining City Walls*, covered in Jasper (a semi-precious stone) alternating green and red. This is only to cover the wall, the foundation and structure can be a regular construction material. The wall is 10 m high and ~30 km long.
[](https://i.stack.imgur.com/pKSef.png)
It it is possible to generate these via industrial manufacture, I'd prefer that over mining. If it is possible to break down the individual highlighted items by price, I'd love to see that, but it is not mandatory. I *may* accept partial answers if one or more of the estimates are impossible to produce. If multiple estimates are available (say depending on carat size), I prefer the lower cost one. Rough Fermi-style order-of-magnitude-estimates ok.
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**Walls of Jasper:** We have 300,000 square meters of wall to cover. Let's assume that each stone is 1 cm x 1 cm, or 0.0001 square meters. Therefore we need three billion stones to cover the wall. Double that for both sides of the wall. Fortunately, Jasper is cheap. At [$2 per stone, give or take](https://www.gemsociety.org/article/jasper-gem-information/), the fancy walls end up costing us **twelve billion dollars**. (Also, your wall numbers aren't accurate, but it doesn't really matter - more on that later.)
**Sea of Crystal:** 681m x 51m is an awful number; I'll call it 700m x 50m, or 35,000 square meters. Therefore we need 350 million stones (at one square centimeter each) to cover it, half of which are emerald and half of which are topaz. *Note: In researching this it seems that my square centimeter estimate is rather large for gems; as such, I'll be scaling prices accordingly rather than recalculate, as you only want a ballpark estimate anyway*. Emerald would go for [about \$400 per square centimeter](http://www.gemselect.com/emerald/emerald.php), while topaz is [about \$50 per square centimeter](http://www.gemselect.com/topaz/topaz.php). Average it out, it'll cost \$225 per square centimeter, or a grand total of **eighty billion dollars** (approximately).
**City of Gold:** We need 400,000 square meters of gold foil. Amazon is currently listing [gold leaf foil](http://rads.stackoverflow.com/amzn/click/B002F9CYQM) at \$50 for what works out to 0.15 square meters. Thus we'd need 2.7 million of them, so it would cost about **135 million dollars**.
**Giant Golden Statue:** I was a physics major in college, so I'm going to do what physics majors do best and assume that the statue is a sphere. 13 meters across is 512 inches (since you put the gold thickness in inches). The volume of gold is then about 412,000 cubic inches. That converts to 4.2 million troy ounces of gold. According to the NASDAQ, 24 karat gold is currently going \$1250 per troy ounce, so our statue will end up costing us just a touch over **five billion dollars**. But wait! That's before the gem-encrusting. The surface area of our statue/sphere is about 827,000 square inches, or 534 square meters. The average gem price I've used so far comes out to \$150 per square centimeter, so I'll just use that. Assuming we only want to cover the statue about halfway (after all, if you cover it all the way you can't show off the gold below!), we're covering 267 square meters for a grand total of just a touch under **five hundred million dollars**. So all in all we're looking at a grand total of about **five and a half billion dollars**.
**The Pearly Gates:** Pearls have many different sizes; we'll say that the ones we're working with are one square centimeter (10 millimeters is a common size for necklaces etc, so that makes sense). The gates are about 50 square meters (12 \* 5 is 60, take out some for the area you walk under). But wait! We have to consider the inside of the gates as well. Revelation says that the walls of the city are 72 yards wide (call it 70 meters because I'm lazy). Ballparking, the surface area of the interior of the gates will be about 800 square meters (we cut out basically a 5m x 2m hole for the gate, so about twelve linear meters, times 70 meters deep). Then we have to cover the other side of the gate as well, so a grand total of about 900 square meters, meaning we need about nine million pearls. But there are twelve gates, so we need 108 million pearls. Pearl necklaces are about a meter in length, meaning that they have about a hundred pearls on them. Estimating a thousand dollars per necklace, we get about ten dollars per pearl, so our gates cost us about **1.1 billion dollars**.
All told, we're currently just under **$100 billion**. Slightly out of reach of Bill Gates, atop the list of billionaires, but they could team up and buy this pretty easily. That, coupled with the fact that you wanted the answer in terms of ratio to the US GDP, makes me think that this number is just too small to be the ultimate holy city for an omnipotent deity. So I went back to Revelation to see what else I could add to put this city beyond the wallets of mere mortals. And lo and behold....
**The Streets Paved with Gold:** Revelation 21:21 tells us that the streets are pure gold. Assuming this means that gold is replacing asphalt, we've got us a LOT of gold here. But first... how many roads are there? Well, a city block is about 100 meters. Revelation 21:16 says that the city "is laid out as a square... 12,000 stadia in length....". A Roman stadium was a distance of about 185 meters. So the city is 2.2 million meters in each direction (remember how I said your wall numbers were off? Yeah....). At that point we'd have 22,000 roads, going both crosswise directions, so 44,000 total. Call it 40,000 to account for double-counting the intersections. Roads usually have asphalt about six inches deep, call it ten centimeters or 0.1 meters. If each road is then ten meters wide, each road has a cross-sectional area of 1 square meter, times 2.2 million meters long, for a road volume of 2.2 million cubic meters, times 40,000 roads. We have a grand total of 88 billion cubic meters of gold in our roads. Gold has a density of about 19,000 kilograms per cubic meter, so our roads weigh about 1.67 quadrillion kilograms (for scale, WolframAlpha says that's about 20 times the total biomass on Earth). That converts to $5.38 \* 10^{16}$ troy ounces, which comes out to **67 quintillion dollars**. That's just under four million times the US GDP. Much more heavenly.
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[Question]
[
Set in a dystopian future, levels of technology similar to today's levels exist with some advances, but the knowledge of how to create and utilize much of it has been lost. Those giant mechanical birds (air planes) are much too difficult to use and coordinate so most trans-atlantic/pacific trade has taken to the high seas.
Enter Ernest, dashing pirate captain of a galleon with a very eclectic collection of technology from the 1800 to the near future (you get to decide what!). Ernest has managed to get his hands on some of the technology outlined in [my other question](https://worldbuilding.stackexchange.com/questions/38796/capturing-wind-in-a-bottle) that can capture, store and release wind (still working on how this works). In addition to a bunch of the hand held containers (about 2 per [seaman](https://upload.wikimedia.org/wikipedia/commons/a/ae/Able-seaman-ww2-2.jpg)), he has a couple very large ones (~15 ft diameter, can capture ~15 minutes of strong wind) mounted on the ship behind the main sail on a swivel so they can be pointed at different things. He also has an assortment different sized containers of various sizes in between.
I am wondering what sort of shenanigans and jerry-rigged contraptions our ingenious anti-hero and his crew can come up with. There is the obvious "use the big ones to blow the sails" type things, but I'm looking for something a little more creative. Good answers could be warfare applications (somehow supercharging a cannon maybe?) or ways to make everyday life on a pirate ship easier (easily drying your hair?). It could also be a direct application of the wind-bottling technology or a combination of it with some other tech on the ship. Since the design of the wind bottle is not set in stone yet, feel free to play with the design a little if it leads to some really cool applications.
Note: Ernest has no fear and will likely be attempting to raid all types of ships from an old Spainsh galleon to a repurposed aircraft carrier or cruise ship -- pretty much anything that floats and may have something valuable.
[Answer]
You would not point it at the sail, but rather it would take the place of the sail. Figuring this out could allow him to make them useful when others could not.
A shenanigan I can recommend is to have a mode for launching a [toroidal vortex](https://www.google.com/search?q=toroidal+vortex+gun) pulse instead of a steady stream. This can do things at a distance (today, for real!) that a steady stream would not, at a fraction of the power.
A possible intended use for such a machine might be for propelling a ground-effect hovercraft.
Don't forget that even ancient peoples had use for compressed air and forced air. You could use it anywhere a bellows apparatus is normally used, such as in a metalworking forge, or working down a mine.
Also consider how you can abuse it! I'm supposing it works like the propeller and battery I outlined elsewhere; even if using unknown and mysterious means, it actually *stores energy* and can transduce that both ways with the momentum of the fluid in the pipe.
Will it pump water too? If it can be *charged* with moving water it will gain much more energy, even if it can't discharge water very well.
You can feed the intake with a hose to some combustible gas rather than using plain air. Combine that with the vortex mode and it will stay together for a long distance, delivering a volume of gas to the opponent's ignition point of some open flame they have, like where they would be lighting cannon fuses perhaps?
[Answer]
well if your bottle is mounted on the ship and you blow at the sails, they will cancel each other out, as the sails get the wind blowing forward, the canister will be pushing backward with the same force on the deck (or the poor soul holding it). So unless you have some magic that the wind doesn't 'push back' using it against the sails to go faster would be pointless.
However pointing it out the back of the ship would give a little boost. It could be very useful for speeding up a turn, if mounted on the back of the ship, turning it one way or the other could significantly speed up a turn, thus messing up an enemies plans. "There going to broadside us sir!", "Spin to face them head on!"
If sitting at rest, it could be used for small maneuvers, maybe to trick an opponent to thinking your are a sitting duck, and then 'sprint' out of the way at the last minute.
It could also be used against another sailing ship, if pulled up alongside, point it up at their sails, it would push the ship over, maybe throwing some of their crew and fighters off into the sea before it rights itself again.
[Answer]
As @bowlturner has dealt with various propulsion ideas I will look at other things you could do.
## With small wind machines
**Diving**
Use the wind power thing to breath while you are underwater. You could also use it as a self propulsion method to escape sharks/other humans that are under the water or use it to get to the surface at speed. Although this risks the bends.
**Parachutes/jumps**
A pirate could leap to an opposing ship up to say 10 metres away while the enemies would not be able to board the pirates ship. They could also leap from the mast to get an unexpected advantage and use the wind to slow their fall.
**Deflection**
A skilled enough pirate could use a quick blast of wind to shove an arrow, grappling hook or boarding soldier of course. Three or four pirates could knock a cannon ball off course.
**Aim**
Still using small winds a pirate could improve the aim of a bullet or cannon ball by giving it a quick blast as it sets off.
**Fire starting**
If you need to start a fire somewhere where there is very little air just blast wind onto the flames to get them going.
**Emergency weapon**
If a soldier runs at you with a sword shove the wind into his chest, it might give you a second to get away. Or use the wind to throw a stone/wood as the soldier. Or use it to blind him using leaves and dust.
**Ambushes**
Use the wind to fan smoke up like an emergency flare. When help comes leap out and kill them all.
---
## With large wind machine
Many of the above can be done on a larger scale using the larger machine but there is an issue that using the machine will push the ship off course.
**Depending on strength - torture**
Tie someone to two stakes about a metre to a metre and a half apart then turn the machine on them at full power. After 15 minutes the strain on their arms will have become almost unbearable.
**Scouting**
While heavier than air flight is out you could launch a glider using the wind to scout around. You could also launch a human without a glider as a punishment.
**Diving**
Use the large machine to propel yourself under so you don't have to swim those first few meters allowing you to get that bit deeper.
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[Question]
[
The concept of a metal poor world is one that I find deeply fascinating.
In part because I fell in love with the setting that first exposed me to the concept, [Dark Sun](http://www.athas.org).
So I want incorporate a very limited access to metal into the back story of my setting. However I don't just want the planet to be metal poor, its more that the peoples living in my world for much of their history had a very difficult time accessing the planet's metallic bounty.
Before I resort to hand-waving I was wondering is there any possible real explanations for why the metal on a planet would be difficult to access.
[Answer]
This is an interesting idea and could easily be explained with scientifically-sound methods.
The main thing that creates metal deposits (we speak more of deposits in the minerals industry, as opposed to veins, which are usually a mode of how metals exist within a deposit) is tectonic activity. Every deposit I can think of off the top of my head - and I'm an exploration geologist, so that's a fair few - has some manner of tectonic influence in its creation. Often that is from the opening up of a new basin caused as a by-product of subduction, meaning there is somewhere for seawater to infiltrate the oceanic crust and be heated up by exposure to the mantle. This causes the water to be able to liberate metals out of the crust and bring them up to the seafloor, where the metals precipitate out due to the change in temperature. This is just one example of tectonic activity driving the formation of mineral deposits.
Where a planet does not have tectonic activity, it will often not have an atmosphere or hydrosphere. It is widely theorised that Earth developed an atmosphere (and as the result of this developed a hydrosphere) as the result of outgassing from the early crust caused by volcanism, which is the result of tectonic activity. There are other ways to get an atmosphere though; massive early bombardment from a comet swarm has been theorised as a way to get enough gas and water onto the surface to develop into an atmosphere.
A planet that formed the same way as Earth that happened to have a much lower amount of radioactive material could have easily cooled down a lot quicker; [something like 90%](http://phys.org/news/2006-03-probing-earth-core.html) of the heat in the core and mantle of the Earth comes from radioactive decay. Random cosmic chance is more than enough explanation for this. And this would have allowed you to have an atmosphere, as the early heat would have been enough to drive tectonic activity, but this would have stopped quickly as the core went cold without radioactive decay to drive it.
Without tectonic activity to drive their formation, mineral deposits would be very restricted. A way you could introduce a *very* limited amount of metals into your world would be through the bombardment method discussed earlier. Approximately 1.9 billion years ago, a massive rock smashed into the crust in what is now Ontario in Canada, resulting the formation of one of the world's [largest nickel deposits](https://en.wikipedia.org/wiki/Sudbury_Basin). Sudbury represents a fraction of a percentage of the world's mineral resources, so it is by far and away the exception in the formation of metal deposits, so you could use that as a plot point to explain why one civilisation is more powerful than others.
[Answer]
Could be your people just doesn't have the technology level to use metal. History of full of complex civilizations that didn't have the technology to use metal( the Aztecs the Mayans the Incas to name a few examples) well these peoples we're still very advanced socially and intellectually they just didn't have the technology to use metal.
[Answer]
How advanced you want your civilization to be? If you don't mind having them at a neolithical stage, then you can go for a completely different approach: lack of oxygen.
If the life in your planet is not oxygen-dependant, then it's quite definitely doomed to stay at neolithical stage of civilization forever. A intelligent species needs at least three things to produce a technologically advanced civilization:
* Being groupal: no matter how intelligent its individuals are, any technical progress is going to require collaboration and team work, if only so for having some of your people to produce food for you so you can use your time for thinking, inventing and creating new things. This includes having a language, since transmission of complex knowledge to the next generation is a must.
* Having a brain capable of 3D vision and abstract thinking, and extremities able to use tools. Ultra-intelligent lions would be dangerous creatures, but they would never build a plane.
* Energy sources
A intelligent but not technologically advanced species can use natural materials to make tools and utilities from them, either organic (wood, fur, bones, organic fibers...) or inorganic (rocks, water). But to reach the next level of evolution, transform these raw, naturally existing materials, into something artificial that cannot be found in nature you need to apply energy. Specifically, you need to alter its chemistry. And the only source of energy that is powerful enough to make that kind of transmutation but can be made and handled by a primitive civilization is fire. Without oxygen, there's no fire, and as such the most advanced civilization you can have is a few steps above of the Neolithic age.
With enough time they may discover some acids or hard bases to dissolve and even melt some materials, but it is unlikely that they can use these to make adequate tools. Fire allowed our ancestors not only to cook and keep predators at bay, but to make new, enhanced tools. Bone can be twisted and wood hardened with fire, metals were melt with fire, food was preserved (among other methods) with fire... without fire, even if you are virtually surrounded by iron ores, they're completely useless to you.
[Answer]
If your planet has already had and lost one species of intelligent technological life it would have very little ore near the surface since it would have been mined out, much like modern day earth. You might have a few pockets of ore that were under important structures or are the buried remains of ancient dumps or scrapyards. Most metal would be very deep or too dispersed to be minable.
basically your planet has already had one species with a technological civilization and it has gone extinct, now millions of years later there is little evidence of them other than the lack of near surface metals. This would make metals rare but not impossible. Deposits would be small or hard to get to.
[Answer]
Silicate dominated geology, metals are relatively easy to access on earth because our metal bearing rocks are dominated by oxygen and sulfur which are relatively easy to drive off most metallic elements, silicate rocks are not so easy to reduce to pure metal. If ore formation happens under anoxic conditions deep in the earth where sulfur is rare then silicates would dominate the chemistry and metal liberation would be much harder.
[Answer]
Prevent the Moon forming event in early Earth history.
That impact scooped off some 40% of all the crust.
Much deeper crust = ores remain buried deeper.
This will not make all ores inaccessible, but it should make the average abundance or ores a lot less.
If you couple this with a planet that is less volcanically active, then you also remove the primary mechanism by which ores are brought to the surface.
OR
You could use the same scenario that Dark Sun itself uses.
There were ores. Plenty of them. Millennia upon millenia ago they were all mined out. You are living on the dregs remaining on the surface thousands upon thousands upon thousands of years after all the easily accessible ores were mined out, and their remains are spread as a thin toxic rust over the landscape.
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[Question]
[
*This story is meant to be an introduction and background for a short videogame I'm working on.*
Our hero works at a secret, hidden facility. The secret is kept among every staff member working there. The involved parties are mostly scientific staff and engineers, but also military staff from countries like USA, EU members, and some Asian and pacific countries (say, NZ, Japan, South Korea—basically, if your country signed stuff like the [TPP](https://en.wikipedia.org/wiki/Trans-Pacific_Partnership), your country is *in*).
The main motivation for the facility is warfare/defense, and so research and development is oriented to build weapons or technologies useful in (conventional) war, quantum computing, chemical and biological warfare, nanotechnology, space exploration, and new energy alternatives (this involves deeply studying quantum mechanics and even further research about the possibility of harnessing zero-point energy).
The technologies developed there were not ready for immediate use, but since Al Qaeda/ISIS have managed to survive and increase their influence, the people at the facility are preparing themselves for the worst (since drones do not seem to be useful now).
The main technology under development was called the *Time Wheel*, which was named after Carlos Castaneda's [work about American shamanism](http://www.goodreads.com/book/show/12843.The_Wheel_of_Time). The "device" is a *predictor* which would produce highly precise information about the possible outcomes of courses of action at a macroscopic level. The study of quantum coherence and superposition is taking place at a level never reached before. The actual technology involved and experimental mechanics are kept highly confidential (even to the main game character, who never trusted these reckless, political-influenced initiatives).
Our hero was worried since he knew about some new actions taken by the whole facility:
* Security and rescue-trained staff was being hired by dozens.
* Most staff members were told to agree to a number of terms, including:
+ Restriction of their civil liberties
+ Restricted access to health care outside the facility for a period of five years (even private medical services were restricted).
+ Accepting new, hazardous working conditions
* Staff members were made to sign legal documents reinforcing the confidential nature of activities in the facility, and warning of severe punishments and penalties for revealing state secrets.
However, in a huge facility, secrets spread faster than Wikileaks, and the Time Wheel experiment was no exception.
The facility is geographically isolated, and our main character, like most of the staff, lives in temporary residence there (they can return to civilization for holidays or work rotation). He cannot communicate with the outside, except for authorized phone calls (that are likely monitored by the facility's security). His computers are likewise monitored: forget about free-access internet. He learned about the Time Wheel experiment few days ago from gossip among the other staff members. He feared for his safety, but was unable to leave the facility. He also could not allow other staff members to learn that he knew about the project, since he could be jailed (or even executed without trial).
**How plausible is it that the experiment was kept secret from a big part of the staff, but that somehow someone was able to leak that information to the hero inside the facility?**
[Answer]
Dr David Robert Grimes, a physicist and cancer researcher at Oxford (and also a journalist) published a paper in January this year discussing precisely the idea of whether a large-scale conspiracy is feasible - [and his conclusion was that it is not](http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0147905). To summarise, he devised a mathematical model for conspiracies involving multiple actors over time. The model predicts that conspiracies involving more than a thousand actors "quickly become untenable and prone to failure."
I'll borrow one of his figures to illustrate the model's estimation of the lifespan of a major secret, given a certain number of actors:
I'm a poor statistician, so I won't attempt to explain his work in greater detail, but he essentially proved that conspiracy theories on the scale you're talking about most likely cannot exist in reality. While you could suggest that your fictional facility/organisation takes measures that have not been attempted in reality so far, I would consider the precedents discussed in the paper fairly convincing. He gives the following examples of some very serious real life conspiracies, the number of people involved, and the amount of time it took for them to become public knowledge:
In other words, to answer your question directly, given the timeframes predicted by this model *it is not plausible that the secret could be kept from the staff, or even the public, and it is highly plausible that the protagonist, given that he is **already inside the organisation** would find out about it.* As for his chances of effecting an escape, that's very much the domain of fiction, however. Although, it sounds like your hero is being kept in conditions *less* secure than a supermax prison, given that he is not confined to a small cell, and has a certain degree of liberty within the confines of the facility - and people [have escaped from maximum security prisons](https://en.wikipedia.org/wiki/List_of_prison_escapes#People_who_escaped_multiple_times), even while confined in solitary cells, and even while they were *known to be and treated as the greatest possible security risk*.
[Answer]
Well, nobody trusts no one, so usually you don't even know exactly what happens in the laboratory next to you. Of course no one told you, but there are microphones and cameras all over the place. Not 100% coverage, and someone still has to check the tapes, but you should not take the risk. After all, would anybody on the outside really note you're suddenly... silent?
---
I think it would be feasible to keep such an experiment secret, as long as the whole facility is about secret experiments.
Also, as mentioned above, you can install surveillance-equipment everywhere, together with signs on every greater cross-section reading **"Always remember, mind your own business!"** or **Please remember: All your work belongs to Black Mesa.**
All of this doesn't work completely (of course). There is always a person who hints how unbelievable more dangerous their work is (and, because of this, how cool they are). Maybe they talk to a colleague from the same lab at the neighbor table at the canteen. It doesn't have to be clear, but maybe one of two researchers is worried something might go wrong with the new Super-condensator and the feedback-loop they induce in the (alien?) crystal. Worst case scenario: A radio-active EMP, or maybe a burst of strange particles.
Your character, smart as he is, hides in the already mentioned *lead infused Faraday-trap (**LIFT**)*.
---
On a side note: You should grab Half-Life (sometimes cheap on Steam), it reminded me extremely of that. Hence the Black-Mesa reference.
[Answer]
from OP
>
> How plausible is it that the experiment was kept secret from a big
> part of the staff, but that somehow someone was able to leak that
> information to the hero inside the facility?
>
>
>
The experiment itself is not a secret. It is "The main technology under development". One of many weird spooky projects going on. The department has a sign that states "Project Time Wheel".
Neither is it secret that people are signing restrictions on their civil liberties. Wartime, etc etc.
The secret thing is that **Time Wheel is freaking way dangerous**. More than the bioweapon monsters, more than the quantum bombs. The danger involved is known firsthand to one person who survived (temporarily) an accident during a beta test of Time Wheel. Maybe even the people who cleaned up the accident are not entirely clear what happened; they might think it is equipment malfunction or something else. The victim is the person who told the hero. The hero might be the only one who knows the truth.
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[Question]
[
## The Background
Imagine a setting in which the only major fictional technology is human teleportation at the speed of light (for this question please ignore the question about how the teleportation device makes it to the destination).
Human beings are able to teleport themselves around the nearby stars *at the speed of light*. What this means in a practical sense is that for the teleported person, no time transpires. Meanwhile for everyone not being teleported, time continues to advance at its normal rate.
So a person who teleports to Alpha Centauri A, turns around, and jumps back experiences just seconds of elapsed time. While the people they left back home experience ~8.6 years of elapsed time.
There is already a teleport booth/portal network in existence between all habitable planets within teleport range of the Earth. Some of the settlements in the Solar System have these booths/portals but there are also several colonies on inhabitable planets within 15-20 light years of the Earth.
## Human History
Empires like the British and other colonial powers, controlled territories across the globe when it would take months for instructions to pass from the empire's sovereign to the various outposts. So from that perspective there is some precedence of a human government being able to control its various functions with long latency between the issuance of an order and its receipt. Obviously some local functionary would take the role of governor to handle the urgent stuff.
## The question
**Could humanity maintain control over such an empire or would it tend to fly apart into independently controlled units (maybe at the stellar system level)?**
Although I'll accept yes/no, I'm more interested in the reasoning behind that yes/no and will rate answers with explanations higher.
### Bonus points
1. Are the any precedents for a single government controlling such an
empire / civilization that seem relevant (links?)
2. Any special points of interest or consideration?
[Answer]
A traditional empire would have trouble staying together long term. Distant planets have to be at least somewhat independent, and any rebellion would have a huge advantage - decades for Earth to even hear about it, twice that for any response, and potentially centuries if they have the option of burying the stargate.
The conventional solution to local rebels is to station lots of troops from another part of the empire, but sooner or later someone is going to decide he would rather be king than governor.
That said, it would be possible to keep control if your ethics are sufficiently flexible.
First, some basic evil scheming:
* No planet can be allowed to be fully independent.
* All interstellar travel is via Earth. If Earth doesn't like you, no trade.
* Keeping all those planets dependent on supplies from Earth would be impractical, but it should be possible to ensure that every planet is importing something important they can't make themselves.
If you want to truly rule the galaxy with an iron fist:
* Governors and soldiers are only posted for a year or so, and know that their families back home will be executed if contact is lost.
* Any loss of contact results in the dispatch of a large rock moving only slightly less than light speed.
* That planet killer capability is also good against alien threats (which may or may not exist). We humans have to stick together.
The other option that can work is an empire in name only. The emperor gives orders which the local governors follow if they feel like it, which works out just fine because the emperor knows not to give orders that won't be followed.
[Answer]
History has shown us that with the right incentives, people will do almost anything (even killing each other or themselves).
Then again some things change history forever. S.O.L travel might easily be one of those things. Consider that regardless of the delay for each individual transport - a constant stream of supplies can be made to happen between one place and another (think of the oceans of methane on Titan).
Most planets will be deficient in one commodity or another (He3 on earth vs water the moon needs). In the transport kind mentioned, trade lines can not be forced without an armed occupation. That, of course, would be very difficult to maintain support if you were restricted to one teleport per planet (other factors would be the cost of operation, whether there was a detectable energy signature when used thus giving away the location of any covert ops,...).
It also represents a failure on the part of the enforcer to have the imagination to solve his supply needs amicably. The normalization of resource distribution of course would depend a lot on the the real costs of the means of transport. If it was very expensive to operate then only very precious things would be transported.
Enough of my musings on the ramifications of the technology. The simple truth is that distance (and time) are a huge factor per the cohesiveness and maintenance of any motivational meme you might try to employ for galactic unity.
There really is no way to keep people from ditching old ideas for new ones (especially given the number of variables we're talking about). Isolated planets (or planets whose teleports broke) may undergo huge evolutionary changes over the time scales involved.
**In short, you might keep a sector of closely grouped star system aligned, but don't expect it on the larger scale.**
[Answer]
Whether the empire can stand or not is questionable, but either way, the people who manufacture and control access to the teleporation technology will have enormous power over whatever government or governments "rule" over them.
[The Spacing Guild in Frank Herbert's Dune Series](https://en.wikipedia.org/wiki/Spacing_Guild)
[The Towers in Anne McCaffrey's Pegasus Series and Rowan Series](https://en.wikipedia.org/wiki/To_Ride_Pegasus)
What governing body rules over any given planet may change as time passes, but the authority of teleportation providers will remain absolute.
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[Question]
[
This is a followup to an old question of mine here: [Would ritual cannibalism of the dead lead to issues with disease?](https://worldbuilding.stackexchange.com/questions/20982/would-ritual-cannibalism-of-the-dead-lead-to-issues-with-disease) The previous question went a good ways into studying a 'safe' way that a culture could practice ritual cannibalism; I now want to look into the cultural impacts of such views.
Let's assume a culture that is technologically at Medieval to Renaissance level of development, but *does not* have a comprehensive understanding of germ theory yet. They originally developed cannibalism in an area of scarce food where ritual cannibalism of their dead was partially a cultural adaptation to needing to never waste any food source. Food need not be as scarce in 'modern' times, but the cannibalism has stuck around. Culturally they look at the cannibalism of their dead as the deceased passing on their strength to the next generation (strength being a bit more literal sense of the very energy of their bodies, not as much figurative powers), and eating the deceased is accepting a final gift from those that cared for you, and in particular in case of family it's seen as a final act of giving: your mother offers you nourishment and strength in death as she did through life raising you etc.
Cannibalism of the dead is done as safely as possible as described in the answer to the linked question. Only safe parts of the body, muscle and certain organs etc, are eaten; other parts that are unsafe for humans are offered to domesticated animals that live with the humans to eat. The body is cooked safely and only ritually consumed if done within certain period of death.
I'm looking for suggestions on likely cultural beliefs and biases that may come out of this ritual. I'm thinking things such as:
* How mourning is done or how one views death?
* What group of people may be looked on either as superior or 'unclean'
based on how safe or healthy cannibalism of them may be?
* How people may respond to a loved one that can not be eaten because
it is no longer safe to do so (most common because the body was
discovered too late after death)?
And rather the lack of germ theory may have resulted in subconscious development of a belief system that protects against disease without the culture recognizing the benefit of the belief (for instance someone who shows symptoms associated with a blood born illness may be marked as unclean and unworthy of eating due to some cultural prejudice without anyone realizing that eating them would result in higher chance of contracting a disease etc).
[Answer]
A few fun ideas come to mind:
**1. Funeral Feasts**
A funeral will involve (or may even be entirely replaced by) a familial gathering in which members prepare and cook the remains of their loved one. Meal preparation and feasts have a historically positive and jovial connotation. It’s possible that this kind of tradition might transform a funeral into a more positive, lighthearted affair in which typical mourning is accompanied by fond remembrances of the good times and a lighter atmosphere. This might increase turnout to funerals.
**2. Last Will and Testament**
Some people might include points in their will or last requests that stipulates who is allowed to eat them or even which parts go to which family members. These restrictions might dampen the mood at the otherwise lighthearted feast.
**3. Death by Disease as a Tragedy**
Death by disease (think Bubonic Plague) might be seen as a terrible tragedy if the person cannot be safely consumed. It might even take on a religious aspect similar to being unable to achieve salvation in the afterlife. This would make contraction a particularly horrific scenario and cause the diseased to be shunned even more.
**4. Royalty Deaths**
The deaths of royalty might create a situation in which power can be leveraged further by selectively inviting nobles or figures who can come to the funeral to dine. Some popular royals might stipulate that their body be used to feed the poor and destitute or the egotistical to see how much they can sell themselves for.
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I want to have aliens approach the Earth looking for a new world to colonize. They come from a similar planet circling a similar star, but either their star has entered its red giant phase (how long could life survive that?) or alternatively, they're worried about a potential supernova in their neighborhood.
I've read that there's really not much for us to be worried about here, so I figure they need to be at least 50 light-years away and the supernova candidate in question is beyond them in the same direction.
Even if they are somewhat more advanced astronomically than we are now, would they have a reasonable amount of warning that a supernova candidate was soon going to blow? Or would it be a situation of "could be tomorrow, could be a million years from now"?
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# A few days, at best
If you want to detect a supernova as quickly as possible, you need a neutrino detector. Supernovae produce substantial amounts of neutrinos - which actually carry away much of the explosion's energy. Even though these particles are hard to detect, they *are* detectable, and can give our unfortunate civilization a slight head start.
### Late stages of stellar evolution
At the end of a massive star's life, its core begins fusing heavier and heavier elements. Each stage of burning, however, is quicker than the last. For instance, while hydrogen and helium burning in a $25M\_{\odot}$ star may take a few million and a few hundred thousand years, respectively, the final two stages (oxygen and silicon fusion) should last only a week.
It turns out ([Asakura et al. 2016](https://arxiv.org/pdf/1506.01175v4.pdf)) that in the final few periods of a massive star's life - starting with carbon fusion - the star cools primarily through the production of neutrino-antineutrino pairs when an electron and a positron annihilate:
$$e^+e^-\to\nu\bar{\nu}$$
These neutrinos have low energies ($\sim2\text{MeV}$) when compared to the neutrinos produced during a supernova (see below), but they should still be detectable through several interaction processes:
1. Inverse beta decay
2. Coherent neutrino scattering
3. Neutrino-electron scattering
Inverse beta decay (IBD) is the most promising interaction because the process has a high cross section and little background noise. Some of our current neutrino detectors (the authors focus on KamLAND) should be able to see IBD from a $25M\_{\odot}$ star at distances up to 700 parsecs hours or maybe even a few days before the supernova, as the star fuses oxygen and then silicon. The detection may not be definitive, but the signal will be there.
### During the supernova
As I alluded to above, supernovae do produce neutrinos. They interact only weakly with matter, meaning that they - not photons - are the first signs of a supernova about to happen. In some cases, they can be messengers of the impending disaster; in others, not so much.
1. **[Traditional core collapse.](http://en.wikipedia.org/wiki/Type_II_supernova#Core_collapse)** In stars with masses $\sim8\text{-}100M\_{\odot}$, fusion of heavy elements will take place, eventually stopping when iron is produced (Iron fusion is possible, but it consumes more energy than it releases, so it does not take place in significant rates prior to a supernova). There is no outwards pressure - a star is in hydrostatic equilibrium, where the pressure from fusion balances the force of gravity - so the star begins to collapse.
Electron degeneracy pressure starts to slow the collapse, but it is not enough. The core continues to collapse in on itself. Photodisintegration produces high-energy gamma rays, and inverse beta decay produces neutrinos. The core continues to collapse, while outer layers are pushed outwards in a "bounce" that is not yet fully understood. From here on, the mass of the star determines whether or not its core will become a neutron star or a black hole.
The two main ways to detect a supernova of this sort are to detect the light from it or the neutrinos produced. The neutrinos typically arrive shortly before the light does, but the difference is not significant, often on the order of a few hours. By the time the neutrinos or the light reach the planet, its occupants will be toast.
For excellent related analyses, see [Lieb & Yau (1987)](http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1987ApJ...323..140L&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf) and [Heger et al. (2002)](http://arxiv.org/pdf/astro-ph/0212469v1.pdf), which also discusses the type of supernova explored in the next section: a pair-instability supernova.
2. **[Pair-instability.](http://en.wikipedia.org/wiki/Pair-instability_supernova)** For stars with masses great than $\sim100M\_{\odot}$ solar masses, gamma rays provide additional pressure against the massive outer layers. However, certain compressions can cause an increase in pair production, the creation of electrons and positrons from gamma rays. This reduces core pressure, leading to a total collapse. The star is virtually destroyed.
Pair-instability supernova typically give no warning ahead of time. In fact, they are difficult to differentiate from normal core collapse supernovae. Careful analysis after the fact is the only way to make a constructive argument to this effect, often dependent on the amount of energy produced (see [Smith (2007)](http://arxiv.org/pdf/0710.3431v1.pdf)).
For more information on supernova detection, see [What technologies and sciences are needed to detect a star going supernova?](https://worldbuilding.stackexchange.com/questions/7238/what-technologies-and-sciences-are-needed-to-detect-a-star-going-supernova?rq=1).
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Another answer is that as soon as your civilisation works out the nuclear physics of stars, it will be able to work out whether its place in the galaxy is a safe one or not. Here on Earth we can admire Betelgeuse from a just-about safe distance. It's a red giant well inside the last million years before it blows. We can observe that it's highly variable ie unstable. If we found ourselves just a few lightyears from Betelgeuse or its ilk, we'd know the only long term future for our cvilisation involved interstellar travel.
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I would like some rare humans (1 in 10 million) to have a mutation that increases their lifetime by a factor of three. In other words, these rare humans could live for ~240 years on average.
But I also need to have **one** of these constraints:
1. This mutation is **not** transferable to their children; or
2. This mutation is transferable to their children, but on a **1/100 ratio**, i.e., only 1 out of 100 children has the same mutation; or
3. They could transfer their mutation, but they are almost **sterile** (rare chances of having one child during their lifetime).
Which one of these alternatives is more realistic, from a biologic point of view?
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Roughly 1% transfer chance *is* achievable.
Suppose you have a gene that is useful if you get one copy, but fatal if you get two (think [sickle-cell](https://en.wikipedia.org/wiki/Sickle-cell_disease)). Now if you breed with a normal person, `1/2` the offspring gets the trait and `1/2` is normal. If you breed with another mutant, again `1/2` of the offspring gets the trait (from either parent), `1/4` is normal and `1/4` is dead.
Now suppose you have `n` such genes, in different chromosomes (independent, so the probabilities multiply), which are all required for the needed trait. Go out with normal person, `2^-n` of the offspring are mutants and `2^-n` normal, the rest are passive carriers of some of the required genes.
Go out with another mutant, the probability for the offspring to live is `(3/4)^n`=`3^n*2^-2n` and the probability to get a mutant is `2^-n` again.
At `n`=`7` you get `1/128` for `2^-n` and `2187/16384` =~ `1/8` for `(3/4)^n`. So 7 in 8 children in a mutant couple are dead or disabled, no surprise they'll keep separated.
The hard part is making them 1 in 10M and not 1 in 128 though. Longevity and vigor *are* attractive. Maybe you should limit their fertile age somehow.
Fun is also likely to begin when longevity genetics are discovered and normal children of long-lived people start looking for a couple who has *complement* set of altered genes. The chances for longevity of the child are *still* 1 in 128 though.
Now if you tell that "longevity is acquired through getting gene1, gene2, gene3..." this is just boring. I would suggest thinking of actual traits, e.g.
**Disclaimer here. I'm not a biologist, need one to refine the following.**
1) Cancer resistance. 1x = no cancer, 2x = cell division is slowed down, no hair, no nails, deficient bone marrow leads to anemia and death.
2) Brain tissue regeneration. 1x = very nice, 2x = brain keeps growing, fills cranium, and dies from obstruction. One can show superior intelligence in the meantime.
3) Very potent immune system. 1x = excellent health, 2x = autoimmune disease of choice.
**EDIT** Maybe you should think of unpleasant but tolerable side-effects of the 7 genes that cancel out if one gets jackpot. This will explain 1/10M distribution. Or it won't, not sure here.
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Actually not transferable to their children (other than the same odds as any other person) would likely be the best. If it can pass on to their children. Any gene of the parent has a %50 chance of being passed on to their children. A recessive gene will need to have another parent with the same trait for it to come to the fore. At this point 3/4 of their children will carry the gene and 1/4 will have it surface. If it was a recessive trait, then all of the long lived children will at least carry the gene, and this means that if two long lived have children their offspring will have (almost) %100 chance of being long lived.
So families with this gene that intermarry will have much higher chances of long lived children. If they have more children over that much longer life span there will become 'communities' of these people.
However, there are other things that cause different genetic issues other than normal gene inheritance. So I'd use either mostly sterile, or some environmental variable (mutation) that causes the change.
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is probably not possible. DNA just doesn't work that way.
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What if their children also inherited DNA from a different long-lived human? The mutation would almost surely be passed down to the child. If it's recessive, as I'm assuming it is, the chance would be 1/4, and if it's dominant it would be 100% likely, which defeats the purpose.
So I believe that option 3 will be your best solution:
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While asking some other questions related to vertical cities, I've found out that the cities can't just expand upward to infinity. There is a limit to how high up a tower can go. There were some conflicting opinions on just where that limit was, though, so I decided to make a separate question out of it.
**In a near-future, how high could we build vertical cities?**
While I'd like this question to be useful to everyone, I do also have a few specific cases for my own writings. I am considering writing a novel set in a vertical city. This city isn't just one tower, but an entire forest of towers, each trying to be above the last. Their bases would be huge (think around five city blocks square or more), and they would have [skyways](https://en.wikipedia.org/wiki/Skyway) on multiple levels connecting them to each other. (I don't know if this would provide more stability or not - there are a lot of them. They are the primary mode of travel between towers.) Each tower is more or less self-contained; that's where everyone sleeps, eats, and works. The streets below are virtually unused.
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Each of the successive tallest buildings of the world has been designed to the limits of current materials and architectural knowledge. As our science advances, that limit will slowly go up.
Thucydides link is very enlightening in that regard. The current record holder, the Burj Khalifa, could probably not have been built 10 years earlier.
As the buildings grow taller, the complexities and especially costs increase. All of the tallest skyscrapers are giant "mine is bigger than yours" projects of hubris built at ridiculous cost. Dubai pretty much went bankrupt trying to build the Burj Khalifa, which now is named after the Emir of Abu Dhabi who financed the rest of the construction.
Super skyscrapers don't make any economic sense and that is probably going to be the biggest limitation in building a city of them. Unless there is really no space left to build, you could house many times more people if the buildings are of a more normal height.
Check out the [diagram of the Burj Khalifa](https://en.wikipedia.org/wiki/Burj_Khalifa) here to see just how small the upper half of the building is. Your interconnected walkways would have to be quite long (and stretchy, to deal with the buildings' sway in the wind).
Here's one complication already happening: The [ground may sink under the foundations](http://news.bbc.co.uk/1/hi/world/asia-pacific/3105948.stm)
Frankly, the rectangular mile high blocks built closely together you see in sci-fi movies need serious handwaving or sci-fi technology.
## Edit: some numbers.
To guess a number, let's take [Shanghai Tower](https://en.m.wikipedia.org/wiki/Shanghai_Tower) which has its roof at 561 meters, only about 30m lower than Burj Khalifa, which has 244m of uninhabited spire. It als has 20% more floor space, a broader top and is in the middle of a high-rise district, so overall a better fit for a vertical city.
Now we can start guessing some improved potential:
* locating the city on bedrock in a mostly earthquake-free zone should allow a whole city of this height.
* locating the city away from the common hurricane paths should allow an extra 10%.
* Increased support from the walkways should balance out against increased storm strength from global warming.
* Improved construction and materials would probably add 10% per decade. A little slower than the past two decades, but in absolute height it's more progress than ever before.
So in 20 years it's about 30% taller: 730m. In 50 years it might be 60% more, about 900m. Round it to 1 km for a nice number, since this is extremely rough guessing anyway.
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Actually no: you *cannot* just arbitrarily add floors to an existing structure (which is essentially using a building as part of a foundation of a new building). the foundation must be properly designed for the expected mass and loads of the structure.
This should answer your question: <http://www.halcyonmaps.com/tallest-planned-buildings/>
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The limit is dictated by economics rather than technology. If you assume that everyone in the building wants to arrive and leave at ground level at least once per day, you get to a point where adding sufficient lift (elevator) capacity to support an extra storey has negative economic benefit because of the nonproductive area it consumes on lower storeys.
One way around that is a vertical city where the denizens of the upper levels do not leave on a daily basis. Instead, there are shops, parks, services, all provided on those levels by people living there. There's still an economic limit, since all the things that they consume still have to be transported up from ground level, but I've read that a mile-high vertical city is not impossible and does not require exotic materials.
By the way, a tall skycraper (with mass dampers) is *less* vulnerable to earthquakes than a much shorter one or a regular house.
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Such cities are often depicted in science fiction. With the right materials there is no reason why such a city could not exist, or go as high as you'd like it to.
There are several things to keep in mind however:
**Geology**
Such a city would be incredibly heavy. If build on anything other than solid bedrock it would most likely collapse, piece by piece. Earthquakes would also work a number on it, since these sort of upward reaching and interconnected towers would be far more rigid than a stand alone building.
**Weather**
If the planet this city exists on is prone to high winds, powerful storms, etc, these cities would once again be threatened. The effects could be somewhat downplayed by technological advances.
In all honesty, if the story is set in the future, where technology is sufficiently advanced, these towers could easily go as high as kilometers, and kilometers, with the old towers being connected together to become the foundation of even larger mega-structures.
Good luck with your novel!
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Thucydides comments that
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> "you cannot just arbitrarily add floors to an existing structure (which is >essentially using a building as part of a foundation of a new building)"
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and he/she is right - in a real world scenario.
However, since this is a science fiction setting, imagine powerful force fields, being used to reinforce those towers, or parts of the buildings themselves being filled-in in order to turn them into massive support columns. Buildings which once scraped the skies being confined within the core of the mega-tower, and becoming underground slums that never see the daylight.
I'm not saying this makes sense with our current technology, or even technology that might be developed within the next century. It just has to sound plausible enough
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Assume that volume scales linearly with height (i.e. we'll roughly approximate the building shape as a cube).
The mass/weight of your constructions will scale roughly as the cube of height (we'll assume the volume of the building scales linearly with height - meaning the x-y footprint goes up as the height does). However the structural strength only scales as the square of volume. So no matter how strong our materials, we eventually get too big to support a bigger building.
Increased materials strength can improve your results but it can't change the shape of the curve - no matter how strong the material. If the building exceeds the size above, it will always collapse under its own weight.
## Materials
To look at this from a materials perspective it helps to have an idea of the pertinent equations.
The force on the building is the weight (mass \* acceleration) of the portions of the building above the current floor.
$$ W = a\_{gravity} \cdot m = a\_{gravity} \cdot \rho \cdot V = a\_{gravity} \cdot \rho \cdot l^3 $$
$$ F\_{compression} = A \cdot \sigma\_{compression} = l^2 \cdot \sigma\_{compression} $$
At max load, the maximum compressive force your structure can support is equal to its weight, so you get this:
$$ a\_{gravity} \cdot \rho \cdot l^3 = l^2 \cdot \sigma\_{compression} \rightarrow l\_{max} = \frac{\sigma\_{compression}}{a\_{gravity} \cdot \rho} $$
V = volume ($m^3$)
A = Area ($m^2$)
l = distance ($m$)
$\sigma$ = material strength (Pascals - $Pa$)
g = acceleration due to gravity ($\frac{m}{s^2}$)
$\rho$ = density ($\frac{kg}{m^3}$)
Maximum measured compressive strength of any material (diamond) comes in at something between 100 & 300 GPa. So make the following assumptions
$g = 9.8 \frac{m}{s^2}$
$\sigma = 300 GPa$
$\rho = 2,500 \frac{kg}{m^3}$
Solve for $l$:
$$ l\_{max} = \frac{300,000,000,000 \frac{kg}{m \cdot s}}{9.8 \frac{m}{s^2} \cdot 2,500 \frac{kg}{m^3}} = 12,244,898 m$$
12 million meters (12,000 km) is a pretty tall building. Your limitation on height would not be due to materials constraints (if you use the right materials).
Bear in mind that this structure would be solid at the base with no room for anything other than structure, the material would have to be diamond, and the crust of the planet it was on would sag so the actual height would be substantially smaller. In fact the shear amount of materials involved would probably be the equivalent of a planetoid (that's not a moon!).
## Foundation
But what sort of foundation can hold up that kind of mass. Although the Earth's crust seems rigid, the reality is it floats on top of the Earth's mantle and is not rigid enough to support even its own mass - it has to float on the Earth's mantle.
The highest points on Earth all exist in the Himalayan Mountain range. In that range, one continental crust is subducting under another. It has pushed the top plate over 5 miles high but this lofty altitude can only be supported by the crust sagging 60 miles or more deep beneath it.
What this means for your building project is that even a sufficiently advanced society are likely to be unable to create large structures of more than 5 miles or before the crust starts sagging beneath the weight of the structure.
## Otherstuff
Typical engineering for ground structures (like buildings) uses a factor of safety of 10x. Meaning you design the building for 10x the load its supposed to support.
This ignores any other forces such as wind, dynamic stresses, buckling, earthquakes, etc.
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[Cerebrospinal fluid](http://en.wikipedia.org/wiki/Cerebrospinal_fluid) is a thin layer of liquid that helps use avoid being knocked out (among other uses). Creatures with a thicker layer have more trouble being knocked out. I want my humanoids to naturally evolve a thicker layer of this fluid. How can I achieve this, and will there be other effects?
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**Make them cavemen.**
Cerebrospinal fluid (CSF) keeps the brain in neutral buoyancy, effectively lessening its weight against itself. This means that the brain can be heavier than it would be otherwise, meaning that it can be denser. Increasing the amount of CSF would mean that the brain could be even denser and still be neutrally buoyant. You might then see more folds in the brain, with increased surface area. Although the size of the brain will decrease, an increase in density could lead to more brain cells.
More brain cells don't necessarily correspond to greater intelligence. [*Homo neanderthalensis*](https://en.wikipedia.org/wiki/Neanderthal) is a case in point here, with heavier brains but not necessarily greater intelligence than modern-day humans. However, a more massive brain could certainly help.
While more CSF means a smaller brain size, [as bowlturner said](https://worldbuilding.stackexchange.com/a/29128/627), it might still lead to an increase in brain mass.
How could you get a thicker layer of CSF? I'm always inclined to say that randomness in evolution will lead to a variety of different results; the mutation in question simply has to significantly affect the organism enough to make it dominant in a species (or lead to a new species). This means that environmental factors may come into play, and I'm inclined to say that the possibility for a slightly higher average intelligence won't be as important.
Therefore, I would suggest that the reason for a thicker layer of CSF could be motivated by its ability to protect the brain. Perhaps the humanoids live in an area where they get banged up quite a bit. They might live in caves that have an unfortunate tendency to cave in, or in forests that tend to have a lot of falling trees. The point is, I'm pretty sure that they'll need to have an environment where they get hit on the head a lot.
Now, a thicker layer of CSF won't necessarily mean a *denser* layer of CSF, and given that (as [Samuel pointed out](https://worldbuilding.stackexchange.com/questions/29127/thicker-cerebrospinal-fluid-results#comment76655_29134)) the density of the fluid is what determines buoyancy, it might not lead to a substantial effect. So I enter Crazy Scenario #1, which is that the humanoids manage to - on a small scale - change the size/shape of their skulls for some purpose. Perhaps they need to squeeze into small places (tiny cave tunnels) to hide, hibernate, or live, which means they have to somehow change the shape of their bodies. This would mean that an alternate skull structure/material is needed. [Cartilage](https://en.wikipedia.org/wiki/Cartilage) could be used here. It is still hard, but not as hard as bone, meaning that some deformation is allowed (although not a lot - think of what it's like to have a broken nose!).
Unlikely? Perhaps. But cave-dwelling humanoids living in small tunnels (if you'll run with my one of my suggested premises) are bound to be different.
[Ville Niemi suggested higher gravity](https://worldbuilding.stackexchange.com/questions/29127/thicker-cerebrospinal-fluid-results#comment76670_29134) an another factor that might be important. Impacts would be even more forceful, leading to a need for substantially stronger cushioning.
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The effect is head-size vs brain-size. The thicker the fluid, the larger the skull must be or the smaller the brain must be. Something has to give.
If you keep heads the same then if more volume is taken up by the fluid, then there will be less space for brain matter. (one reason we likely have less is we gave it up for brain cell space, trading the protection for more smarts.
So if the brain stays the same, then the skull must get bigger. This would give bigger heads and also more weight sitting on top of the neck, making whiplash a possible fatal accident unless you increase the the neck muscles and bones to handle the larger mass.
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**Make it more viscous rather than a thicker layer of it.**
This way the creature doesn't need to have a larger head or a smaller brain but will attain increased protection from shock. If the humanoids can get some connective tissue growing between the brain and skull, like adipose, they'll be as well off [as a woodpecker](http://mentalfloss.com/article/30731/why-dont-woodpeckers-get-brain-damage) and could bang their heads against trees all day long.
Of course, they'll be literal fat heads. But don't call them that, they can easily headbutt you in a fight and win.
Note that viscosity is correlated with density. To maintain the density ratio between the more viscous fluid and the brain, the density of the brain should also be increased. As [HDE226868 suggested](https://worldbuilding.stackexchange.com/a/29134/3202).
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A group of people time travel to ancient Greece while wearing modern clothing and bringing modern technology. They arrive in helicopters and fly over to ancient Athens, where they land. When they arrive, some of them make phone calls and put their phones on speaker. Some of them decide to log into their laptops in front of many of the ancients. They use portable microwaves to heat up their food before eating it. Some of them build working robots in front of the ancients.
Would these people be mistaken for gods and goddesses by the ancients?
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Yes they likely would.
Gods and Goddesses are things that they believed in.
The concept offers an easy explanation for why the time travellers are laden with artefacts of a seemingly "magic" nature.
Or they might think that they stole or were given their gadgets by Gods.
Or they might not jump to any conclusion and simply ask the travellers to explain where these artefacts came from.
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To the Greeks, the time travelers can
* Fly (helicopters)
* Bewitch inanimate objects to move (helicopters and robots)
* Make voices come from nowhere (phones)
* Create light and sound from boxes (microwave and laptops)
* [Do whatever other things the laptops can do]
To the Greeks, the use of flight sounds a bit like [Helios](http://en.wikipedia.org/wiki/Helios) (though [Daedalus](http://en.wikipedia.org/wiki/Daedalus) (a human) could also do it, do some extent). The fire sounds like the work of [Prometheus](http://en.wikipedia.org/wiki/Prometheus) (a Titan). The mysterious voices coming from nowhere could be [the Anemoi](http://en.wikipedia.org/wiki/Anemoi) (basically wind gods) whispering. The robots could be the work of Daedalus).
These miracles could be the work of any of a number of mythical figures put together.
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Mistaken for Greek gods and goddesses? I'm going to say no. Unless your time travellers are actively claiming to be those gods, and even then, they'd have to be carrying some pretty specific tokens of identity. Many Greek deities had identifying equipment (Dionysus's thyrsos staff, for example, or Athena's aegis) that was quite central to their image of the deity, and absent those items they wouldn't assume these newcomers were THEIR gods. Especially considering that your time travellers wouldn't speak Greek and would dress in strange fashion. They'd be considered barbarians, and probably Eastern barbarians at that, given that pants were pretty strongly associated with Near Eastern peoples, including the Persians and the Amazons.
The Greeks did recognize foreign gods and some were respectful of them when visiting or living in other lands, you know, just in case, but I think even with that they wouldn't assume a strange newcomer was a god. They definitely had concepts of superior technology (see: Daedalus) and magic that could be used by mortals, especially mortals with godly favour or ancestry (see: Medea, Circe). They might call them Titans, or assign them demigod status. It would also be reasonable to have the Greeks assume they were favoured in some way by some gods - not necessarily their own unless your time travellers claimed as much. But straight from zero to Olympus? No. Not even Herakles managed that one.
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I can see them believing the time travelers to be Gods, but the possibilities of oracles, wizards, or [magical] alchemists crosses my mind only too strongly, depending upon what the time travelers had at hand upon arrival.
The foreknowledge of events to come, and even a general understanding of natural events and materials not yet understood by (or even known to) the ancient Greeks would give them God-like knowledge.
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Greeks would be highly confused.
First of all, they had no concept of automotion. Even gods travelled in horse-powered chariots (save Hermes, who had his winged sandals). How can a thing move by itself was beyond them.
Second, they had no concept of magical artifacts. The closest to magic I gather were the Phaiakians' ships.
Finally, the god-to-human encounters were quite limited. There were very few lucky (or unfortunate) people interacting with gods directly. Almost all of such interactions were were initiated by the divinity (as an exception I can only recall Actaeon stumbling upon Artemis), and in all of them the divinity had the reason to appear, like grant supernatural powers, give an advice, or punish. Your visitors do nothing like that. No gods for sure.
Quite powerful yes. Maybe even Aethiopians. But they don't speak Greek and know no Homer, which makes them Barbarians. Confusion it is.
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This is the first question in a series that I have (that follows the human organ systems). This question deals specifically with the use of the muscular and skeletal systems in a robot. Since they work so cooperatively, I'll ask them together.
I'm imagining soft-SF answers (not technical... unless it's 100% impossible).
Say bones and muscle tissue can be fabricated/ grown using stem cells. Could they be "transplanted" into a working humanoid-robot with an artificial intelligence similar to the human brain?
If so, then the robot would need to provide, through a system similar to the circulatory system (which, for all intents and purposes, we will assume is covered/ can be emulated by tubes and wires), energy and nutrients to each cell to sustain them.
I'm not trying to say that this would become a fully sustainable species of hybrid human/ robots, but it's more of a teaching tool for the robot to understand the, in this case, limits of the human skeletal/ muscular systems.
I do plan on asking about each of the major body systems as time goes on, so if you are free for some time and want to go into greater depth about any other system and how it could/ not work and why, that's your prerogative.
Don't penalize me for offering, as my question just tackles the m/s systems, but it's pretty obvious that I'll be covering each eventually, so if you have an idea and want to roll with it across other systems, feel free.
[Answer]
With our current medical and technological state, it is utterly impossible. Reasons are briefly listed below:
* Muscles need a constant glucose supply. It is not as simple to provide that in a robotic setup.
* Muscles also need a constant supply of oxygen in the form of oxygenated hemoglobin. You can't just "pump" gaseous oxygen to them and be happy. That won't work. You will need a full circulatory system with heart, veins, arteries and all.
* Muscles also require a very detailed and precise nervous system. It is not easy to get the muscles do something accurately with robotic electric signals. You would need the complete nervous system (or its emulation).
* Muscles also require an immune system to fight off bad guys like necrosis pathogens etc. Without these, the muscles would quickly get rotten by the action of pathogen bacteria.
* Muscles also require a complete setup of endocrine system (glands and stuff). They need a feedback system for growth, repair and all that. Without these, they will shrivel up and die soon.
* Like all other cells in the body, muscles produce waste products (CO2 and water) which needs taking care of.
* Muscles have a limit of power and the best way to use their power is by attaching them to bones. Steel is far too heavy for muscles usage and muscles would give a very bad result with that.
So no. In the absence of a complete biological environment, you cannot have muscles alone in a robot.
[Answer]
## Path 1: Biologically Inspired
You'd have to decide which path you want to follow. Remember, biological systems evolved in a particular context, the most salient characteristic being the absence of human engineering and mining capabilities. So while saber-tooth tigers and the like might have wished for claws made of carbon steel, tungsten carbide, or of graphene-based nanoplateletes there seems to have been no easy biological evolution process to amass and structure the materials required. While some biologically-generated substances are rather amazing (see limpet teeth or spider silk), intelligence-driven engineering can take a far more directed and therefore effective approach.
So you could go for biologically inspired, but physically superior versions. Think moderately bullet-proof skin, ability to jump over tall fences, sustained running at 50mph, and so forth. The only current downside to human engineering is that due to our limited ability to manipulate structures at a molecular level at the moment, our designs are *rather bad at self-repair* compared to natural systems, but that will likely be corrected in the coming decades, as our nanotechnologies progress and mature.
## Path 2: Biomimicry
Perhaps the human technology level has not advanced enough. After all, you have to have an energy delivery mechanism, maintenance and repair down to the molecular level, waste disposal, dealing with foreign bodies and pathogens... It's a headache. Perhaps it's easier to just go with a customized biological design. At that point, you're essentially growing body parts and you're letting the cell programming take care of things like vascularization, lymphocytes, more generally cell specialization and replacement, etc.
From a story perspective, you'd have the outwardly indistinguishable robot plotline going. Which may be a plus or a minus, depending on how it's played. On the downside, integrating biological and synthetic components might be a headache at those lower technology levels, as biological entities tend to build biofilms and deposits over whatever they identify as a foreign body.
## Path 3: The Robopathogen
While you could in theory design a superbody or engineer a human-indistinguishable biomimic in a vat somewhere, it may be ... um ... easier to simply take one. Imagine an alien-like scene where the Robopathogen clamps on to the face of its human victim and drives a sharp proboscis into its victim's brain, spewing its nanomachinery inside, where it will take over all higher thought processes. Perfect for infiltration, it may even have access to the victim's stored memory systems if sufficiently advanced.
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Assuming that all the metabolic/immune system problems cited in other answers can be solved, **you'll still have a tough time with controlling those muscles since we don't currently have a good neuron/silicon interface.**
The Holy grail of cybernetics since the beginning has been to get neurons and silicon to interact directly and while lots of work has been done it's not that great yet. Getting single neurons to talk to a single patch of silicon has been achieved but to control entire muscle groups will require considerable advances.
Consider the reach of our nervous system in relation to our muscles. Every muscles fiber interoperates with a neuron in a vast neural net. To achieve comparable levels of muscular control, these muscles will need to have equal access to muscle fibers. There's a spectrum across which this may be achieved starting with full neuron control at the muscular level all the way to full metal-nerve control.
Full neuron control means that the muscles will be instrumented with the normal neurons with the neuron-silicon interface controlling an entire muscle. This is the easiest to wire up because the number of integration points are relatively few.
Conversely, if the muscles are instrumented with silicon nerves then mechanisms will need to be used to distribute and maintain those individual connections between nerve and muscle fiber. I suspect that there are changes to the ways that muscle fibers and nerves interact during muscle growth. If this robot is doing any kind of non-trivial exercise, the muscles will be reorganizing. This is gonna be tricky and requires a level of nanotechnology that we don't have right now.
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I come from a small costal town, and recently we've been having some giant trouble.
This particular giant isn't particularly evil, but he eats cows like crisps and frankly we're all rather worried what will happen when the herds run out! He's about 60' tall and unfortunately not at all dimwitted.
We have a medieval level of technology so planes and bombs are out of the question but we do have a fairly hefty trebuchet!
We don't actually want to kill our marauding giant. That may bring more of its kind, how can we hope to overpower and restrain him so we have a fighting chance of converting him to vegetarianism before we end up on the menu?
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I'm not sure how you will convert him to vegetarism, but you can worry about this after he's caught.
To overpower him, you need to get him down on the ground. You might try make him slip on a bunch of loose logs, large amounts of oil or maybe even mud, released at the right moment. Unfortunately, he'll probably fight your attempts to restrain him right away causing large amounts damage and killing your people. So poison would be probably a better solution, well hidden in his "meal" (strap it to a cow or two ;-)).
This [paper](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2359130/) suggests that mandrake as a possible candidate. It also describes a technique where a certain sedative is applied by inhaling (yield sponges soaked with sedative at the giants mouth nose if you prefer more action).
Now he's flat down on the ground, you can start restraining him. Hurry before he wakes up. Given his size (and therefore, strength), you'll need vast amounts of strong rope. Use nearby trees and bury logs to secure the ropes.
Given that you never caught a giant before it's still risky. But your local healer surely has a poison to keep him weak or tired to add extra security.
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On the same idea as Marcus, but slightly different method of delivery.
Use punji sticks coated thoroughly with [wolfsbane](https://en.wikipedia.org/wiki/Aconitum). Dig holes (4-5 ft deep) in the ground around cow pens and bury several punji sticks. He steps on, foot sinks in the hole, gets impaled by several punji sticks. Would get limp. Would not be able to run swiftly, so you can safely chase him from a distance silently.
After he's down due to nervous paralysis (he will weaken, then get on his knees and finally drop down on his side), go in and tie him up strongly. Rest is up to you.
Make sure to install artificial respiratory aid (by utilizing a blacksmith's bellows) until poison effects clear out and he breathes naturally.
[Answer]
Poison the cows (well, not really).
Collect some herbs with laxative properties. Pack them tightly, and discreetly tie those to the cows. Bonus points if you can somehow make all the cows look "sick".
The advantage of this method is that you do not need to convince the giant of anything; in his own volition he will change his diet or go elsewhere.
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I'm going to take a different tack. Rather than restrain him and convert him to vegetarian, why not try to deter him with a method that is cheap, non-lethal, and mean: **trebuchet full of rock salt.**
Pain is a fairly effective deterrent in intelligent (and not so intelligent) life. So you figure out where he is coming from, set up your trebuchet a fair bit outside the town (very important because this next part is going to suck for the giant and he might be a little peeved), load it up with some chunks of salt that aren't large enough to kill the giant, but are large enough to pierce his skin, and shoot him. It may be wise to have a back up plan in case that isn't enough to deter him, but I defer that to the previous answers.
(It should be noted that I got this idea from a friends grandfather who drove off a bunch of home invaders with a shotgun loaded with rock salt.)
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# Sic a wizard on him.
Giants mean magic, to beat that pesky square-cube law. So it's just a matter of figuring out the magic and applying it.
# A boatload of archers.
Archers can put out an eye. And he's a BIG target. Find out how well he swims, by putting your archers in a sailboat. Easier to flee, and he won't be able to run them down (negating his best advantage). Mind the boulder-flinging.
# Get rid of the cows.
No crisps, and yeah, he'll have to figure out what to do then. If your neighbors also take a nice vacation, there's no more food for him, and he'll move on - since he doesn't seem inclined to raise his own cows.
# Hire a more amicable giant
Takes one to beat one.
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In 1869 a [giant space gun](https://en.wikipedia.org/wiki/From_the_Earth_to_the_Moon) was built, with the intent of firing a projectile at the Moon, just to prove that they can do it. Of course, the ludicrous idea to put people inside it was never even taken into consideration, as the acceleration would kill them, and if not, the crash into the Moon, or the lack of an atmosphere would finish with them : it just fired a normal cannon shell.
The experiment was a success, the cannonball hit the Moon and formed a nice little crater, an event being seen and photographed by astronomers. However, as it didn't have any other use, it was quickly abandoned after the first experiment. They coated the interior with wax and put a cover on top of it to keep rust and rainwater away, so it survived mostly intact to his day.
Could we find any useful propose for it? Could it have been of any use in the space race of the 1960's and 70's?
I guess the only benefit is that it's already built by our ancestors so it is completely free: we don't have to spend money and resources for building it. However, as it is built completely vertically, it's not useful to achieve (unaided) orbit around the Earth. Also, the high initial acceleration would probably destroy any sensitive electronics or other equipment we tried to launch with it. Could we design projectiles to limit this? If we can't find any use for it now, could we in the not too distant future?
The only use I might see in it, is to send bulk raw materials to a space station or a Moon colony, but we have neither a Moon colony, nor a space station requiring bulk raw materials.
The cannon is as close to Verne's idea as possible, has a bore with a diameter of nine feet (or slightly less, but not by much), is cast directly and completely into the ground on a hilltop in Florida, is completely vertical, and long enough to be able to be used to hit the Moon with a single explosive charge available in the late 19th century. If the later proves to be physically impossible, then we can modify the original experiment so that the cannonball left the atmosphere, but failed to reach the Moon, instead falling back and splashing into the ocean.
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I think the answer is "no". Even if we could build a payload that would survive the launch and reasonably-soft-land on the moon, there are so many other components which require a more gentle launch. Running both systems in parallel, with the gun for a few supplies and rockets/shuttles for the rest, just isn't cost-effective.
* The supplies should land very close to the moon base, but not directly on top of the buildings. Minor differences in wind and air pressure during the launch would give major differences on landing.
* The operation of the gun might be no cheaper than a rocket. Look at the description of the [Paris Gun](https://en.wikipedia.org/wiki/Paris_Gun#Projectiles) for wear on the barrel.
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The earth's thick atmosphere is a show stopper for guns to space.
An important quantity is [Max Q](https://en.wikipedia.org/wiki/Max_Q), the maximum dynamic pressure during flight. Most spacecraft endure a Max Q of around 35 kilopascals.
$q=.5\*\rho\*v^2$
v is speed, $\rho$ is air density. Doubling speed quadruples q. Tripling speed means a 9-fold increase in q.
Let's say we achieved orbital velocity at the top of Mt. Chimborazo. Dynamic pressure would be 18,000 kilopascals. About 500 times as much as the Max Q a typical spacecraft endures.
A severe hurricane with 160 mph winds has a dynamic pressure of about 3 kilopascals.
To endure an 18,000 kilopascal Max Q, an *extremely* robust structure would be needed. As well as an extremely robust thermal protection system (Most meteors burn up in the mesosphere 70 kilometers up where the air density is less than 1% that of sea level).
Also 18,000 kilopascals would slow the projectile down. Atmospheric drag would steal a lot of speed before the spacecraft ascended above the atmosphere.
Space guns, slings, rail guns, etc. are much more viable on airless worlds like the moon, Ceres, or Mercury.
Mars is nearly airless and has some very tall mountains. [I believe a rail gun from the top of Olympus Mons could achieve orbital velocity](https://space.stackexchange.com/questions/8016/is-a-railgun-up-olympus-mons-possible/).
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The gun's no good for Earth orbit -- it's aimed in entirely the wrong direction. It is, however, quite useful for exploring the Solar System.
Building durable electronics is no problem: accelerating a projectile to 11 km/s over a 300 m distance only requires an acceleration of 20,000 times Earth's gravity, less than what a [guided artillery shell](https://en.wikipedia.org/wiki/M712_Copperhead) experiences.
Once you get out of Earth's gravity well, a solid-fuel booster and possible Lunar flyby will let you get anywhere you want. The inability to launch liquid-fueled engines means you're probably limited to flybys, but the reduced cost of launching means you can fire off a *lot* of them.
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Unfortunately the inhabitants of the moon resented our unwarranted and indiscriminate shooting at them. They have long memories and are very revenge-minded and having developed the technology they are shooting back. They refuse to negotiate a peace.
We use the original gun but with a modern warhead to subdue them.
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A 19th century gun is simply not capable of accomplishing this--no chemical propellant can provide the required velocity, a cannonball can't hope to make it through the atmosphere. However, the statement is that it works, so lets see what we can do:
We will have to handwave the propellant issue. There's nothing they could have built that would do it. However, the atmosphere is another matter--if you make the gun very big and the shell very long (and dense) you can make it into space. The acceleration is tremendous but could be within the range of current gun-rated electronics so putting something useful in space isn't out of the question.
Another answer dismissed it as useless for putting stuff in orbit but that's not true. You can put something in **low** Earth orbit for little cost with this--you fire the shell almost straight up, you want it to fall back on a path that skims the atmosphere--you want to scrape off a bit of velocity but not bring it down. Velocity changes at periapsis will lower your apoapsis but leave your periapsis unchanged. (In practice the drag isn't a point source, your periapsis falls a bit but nowhere near what your apoapsis does.) When your apoapsis is low enough you light the solid rocket you brought along to circularize your orbit. Presto, you got a satellite in low orbit with only throwing away a little solid rocket.
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>
> Every child is afraid of the darkness. For them its not simply the absence of light, its the absence of information. Even if you know that there should be a wall or a doorway right in front of you, how can you be sure without seeing it? What other dangers might lurk there, besides stubbing your toe on a chair, and what was that movement you just saw out of the corner of your eye?
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> But what if all this wasn't just imagination, What if the darkness itself could take physical shape?
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I started exploring this idea, where in a dark space "things" would manifest over time, similar to how fog condenses into dew, except that this dew can move, has some simple instinct-based intelligence and mild hostility towards sources of light an heat. When exposed to light (electromagnetic radiation with wavelengths < 1000 nm) the creatures would quickly disintegrate, but something the size of a wolf - which could materialize during a long cloudy winter night in an open field - would last long enough against a torch or small flashlight to cause some serious harm to the wielder.
To make sure things don't get out of hand, the maximum size of creatures is based on the geometry of the space. A half empty tetrapak of milk would simply spoil faster, a drawer is big enough for a bunch of fruitflies, the space under the bed or in a wardrobe is ideal for bugs or a couple of mice, a cellar with broken lighting could generate something cat- or dog-sized and deep caves can house huge horrors.
I ran into problems with explaining the process behind this natural phenomenon, specifically the conservation of energy. The creatures need to have at least some mass to be dangerous or they could be defeated with a ventilator, but generating mass from nothing is hard. Bonding together surrounding air molecules could work, and with 1 $m^3$ air weighting roughly 1kg, it corresponds well with the creature sizes i listed. But when the creatures are made from highly compressed air, every sunrise would be announced by a devastating wave of explosions, which turns the original design upside down by making light more dangerous than darkness.
**Question:**
By which scienc-y process could the described creatures spawn from dark spaces, while using as little magic and handwaving as possible?
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The real problem you are facing (if you want to make it science-compatible) is not to create explosion-free dark creatures under the consideration of conservation of energy/mass. The real problem you are facing is *how* would matter condense into creatures of given shapes and sizes.
As in, can we create dark creatures in a lab under scientific supervision? Can we study their qualities? What force triggers their creation? If these creations are made up of matter, why aren't they produced in light? What about their inner systems (circulatory, nervous, respiratory etc)?
You would notice the more we get into scientific details of mythic creatures, the more uncomfortable it gets. The rule of thumb is, unless you are writing science fiction (which it doesn't appear to me), you have to do a huge amount of hand-waving and nobody would argue back with you about it.
Take for example, the case of Avatar. In this movie, the "soul" of the hero is passed into his avatar by some magic ritual at the end of the movie. Nobody is going to question it, because it simply fits the theme so well.
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OK, this was my piece of advice about the introduction of mythic creature in a horror/fantasy based universe. Now back to your basic question.
The process of creation of dark creature involves air and water molecules sticking together. (How you explain it, is your choice). The process occurs very slowly and is endothermic. Similarly, reversal of the process in light also occurs very slowly, but is exothermic. Which means ... when sunlight falls on a large dark creature, its outer body melts away immediately, but the inner body has been condensed so much that it would take lots of time to gradually melt it away. So even if a dark wolf steps in the sunlight, it would not burst with an explosion. Rather, it's mane would immediately evaporate, while it's inner body would appear to slowly sublimate into nothingness (its matter would be dissolving into air alongwith release of energy).
In order to make a dark wolf explode, you would have to place it in a very intense beam of light that pierces it all the way. X-ray machines would probably be their worst nightmares!
[Answer]
Well, as scientists have found out, the universe is full of [dark matter;](https://en.wikipedia.org/wiki/Dark_matter) indeed there's more than five times as much dark matter than ordinary matter. Now dark matter is called such because we cannot see it, but only see its gravitational effects. It is thought that it consists of particles that don't interact with light, nor with ordinary matter, except through their gravitation.
Well, it turns out scientists are wrong about this last part: Dark matter *does* interact with light, but not in the same way as ordinary matter. Namely electromagnetic radiation effectively switches off their interaction. So as long as there is sufficiently electromagnetic radiation (such as light), it will behave exactly as describes by physicists. However, in darkness its attractive forces turn back, and its behaviour starts to get very similar to the behaviour of normal matter.
But where does the energy come from? Well, from [dark energy!](https://en.wikipedia.org/wiki/Dark_energy) It's everywhere, and we have not the slightest clue what it is, except that there's even more of it than dark matter, and it pushes our universe apart. So let's say that dark matter couples to dark energy in a way that it gains an attractive potential, making it clump similar to how ordinary matter clumps. Now electromagnetic radiation will disturb that process and decouple dark energy and dark matter, giving both the properties the physicists unconditionally ascribe to them. When the electromagnetic radiation vanishes (it gets dark), then the clumping of dark matter sets in.
Now to explain how the condensing dark matter generates life forms, rather than simple clumps/drops of matter (like the condensing fog) needs some more serious pseudoscience (maybe something with morphogenetic fields).
[Answer]
First off, invoke Sanderson's [First Law of Magic](http://brandonsanderson.com/sandersons-first-law/):
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> Sanderson’s First Law of Magics: An author’s ability to solve conflict with magic is DIRECTLY PROPORTIONAL to how well the reader understands said magic.
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This is key for avoiding writing yourself into a corner in a desperate attempt to over-explain magic.
Personally, I think it would be terrifying if such a creature could play on our fears to make it seem to be more than it actually is. Rather than actually trying to make something which has a mass of a wolf, use people's fear to manipulate them into never actually testing its mass in a scientific sense. If everyone involved believes the creatures of darkness are actually flesh and blood creatures, does it matter if most of it is in their head?
This could play into any number of storylines you would like it to. For example, consider that perhaps a flashlight *doesn't* actually disperse the fog creatures, but rather makes it easier for us to see what they actually are, and thus be less fearful. This would mean that, if you are truly terrified out of your wits, not even a flashlight will save you.
No humans around? no problem. all you have to do is deal with a light weight creature which is more subject to winds dispersing it. It would have to spend energy to keep its shape in a wind. Interestingly enough, this means that the creatures are more powerful around fearful humans, so would have a completely rational reason to seek them out and scare them more...
[](https://i.stack.imgur.com/zwWUu.jpg)
... and more, and more.
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<http://tardis.wikia.com/wiki/Vashta_Nerada>
This sounds similar to what you are looking for. Thought Dr. Who does not specify how they evolved.
Rather than say it is a creature made out of darkness, it may be better to just make them creature that evolved naturally. They are absolutely deadly in their shadowy domain, but cannot survive long outside it. They appear to be like a cloud of darkness, but are a hive-minded group of extremely small animals.
As to why they cannot survive in the light, rather than pale like most low-light life forms, these are absolutely black. This way they blend in, making them better predators. But the flip side is that their bodies absorb light too efficiently. When exposed to a certain level of illumination they quickly overheat, eventually self-immolating.
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[Question]
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As is well known, the [battle of the Teutoburg Forest](https://en.wikipedia.org/wiki/Battle_of_the_Teutoburg_Forest) was an important turning point in the history of the Roman empire.
Now a time traveller goes back into that time in order to change history, with the goal to have Varus win. However it is not possible for him to take any modern/future artefacts with him; not even the time machine itself. He can only transfer himself back in time, and program a point in time when the time machine automatically takes him back to his own time; if necessary, he can repeat that several times (provided his change in the time line didn't make the time machine vanish). So all he can do is to learn as much as possible about that time, and use that knowledge to try changing the history using contemporary means.
So what could he do to make Varus win? Of course he can inform him about the plans of Arminius, but then, why would Varus believe him? And could he do anything else? Maybe use future knowledge to provide Varus with better weapons?
Note that he can't simply kill Arminius as child, as that way Varus would not win the battle because there would not be any battle.
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The key to the Germanic victory in the Battle of Teutoburg Forest is that they ambushed the Roman legions while those legions were strung out along the path of travel. Take that away, and with near parity in numbers, the superior Roman training will let them win.
*Preventing* the battle is easy: go back in time to before the battle, establish yourself as leader of the unit responsible for scouting for the army, and ensure that the German forces are spotted well before they can attack. The problem is bringing the Germans to battle: Arminius is knowledgeable enough about Roman tactics to know he can't win against an army in battle formation.
The Roman forces were strung out along 15-20 km of ambush-friendly terrain -- so spread-out that the various units would be almost entirely unable to support each other. With that sort of tactical disadvantage, no weaponry advantage short of modern automatic firearms is likely to turn the tide, and even that might not be enough.
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Well if he was willing to sacrifice himself in the name of helping Varus win, then getting caught and 'questioned' pretending to be a spy from Arminius telling all that he knew about the ambush, then most likely he would use that information to increase a victory, however, the the chance of survival for our intrepid time traveler, go down, likely seeing his last sunset from the posts of a cross.
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Suppose tomorrow, on present-day Earth, a group of scientists published a paper detailing a series of experiments conducted over the last ten years that successfully activated and deactivated the quality of life that makes a creature intelligent. The means of this technology could be a specific radio signal, manipulation of DNA, or what have you; it's not pertinent to this question.
*How would general society respond to this development in both the immediate and long-term time frames? What legal and cultural ramifications would occur?*
Whatever the means of controlling intelligence, assume it is easy to produce in a dedicated lab, but not trivial or inexpensive. The cost to produce this effect is roughly \$25,000 (US) (with working equipment) and can be done by a team of four scientists and one engineer. Building the necessary equipment requires four months of dedicated work, \$100,000 (US), and 5,000 sq. ft. of workspace (space for security apparatus and private power source included).
Creatures made intelligent by this process don't spontaneously start speaking human languages; they are still limited by their physical capabilities. However, their new-found intelligence does offer them the ability to learn human language as easily as the average human. When a creature is first made intelligent, it is roughly equivalent to a three-year-old human child; creatures made unintelligent revert to their previous state (ape-like for humans). Creatures with larger or more complex brains (e.g., sharks, dolphins, elephants) can achieve a higher final level of intelligence, potentially exceeding current human levels of intelligence; insects, spiders, mice, and similar small creatures barely progress beyond the initial intelligence state.
As implied above, currently-intelligent creatures (i.e., humans) and newly-intelligent creatures alike can have their intelligence turned on or off via this technology. The process requires between 4-8 hours of work, depending on the individual involved; the individual must remain still throughout the process, usually through sedation. A creature can be forced to undergo the process, typically by being sedated first.
[Answer]
**TL;DR:**
Realistically, I'm going to hazard a guess that this would end up like most modification experiments (such as cloning or modifying our own intelligence) and would be split down the middle of those who would like to make animals intelligent and those who don't. It would probably be banned on humans as there would be huge ethical concerns.
*Before I get started, let me just define that every time I say "intelligent" or "intelligence" I refer to human intelligence, and "animal" means all animals minus human.*
# Against
* Some societies think that animals must be below them. Religions come to mind first as several state that humans were created as intelligent beings and are the only intelligent beings in the universe. They may pressure the government to ban the technology outright out of ethical concerns (We've banned human cloning for the same reason).
* Animals may notice that their fellow animals are being harmed/caged and lash out (Think Rise of the Planet of the Apes). People may be concerned for this and even if they allow animal intelligence, they would probably be given less rights than a human. They can't be allowed to congregate, would likely have communication heavily restricted, would likely have mating restricted or not at all, and would likely have someone ready to kill the animal in the worst case scenario.
* Militaries might take advantage of this. I mean, how would you know what animal is intelligent and what one isn't? Trained operative animals could disguise themselves as being a regular animal and infiltrate secret facilities. A bird is flying over a secret military base right now. Should they shoot it down out of concern for privacy like they would any aircraft or risk having information leaked? A lot of animals would have to be killed because they entered restricted airspace/got in through other means.
* In terms of humans I don't really even see this being tested, let alone practised. Forget the huge costs involved, the huge ethical concerns would likely arise by turning off someone's intelligence would stop most labs from conducting the experiments. There are many experiments today we've banned on humans due to ethical concerns.
# For
* Scientifically, what an achievement. There will most likely be several experiments conducted by independent scientists to test the theory in the paper. There may even be some stories early on to bring attention to the new technology (Think of how cloning was brought to light when Dolly the sheep was cloned).
* Likely we'd turn on the intelligence of an animal with a large brain. If our brain can think of complex ideas, could a larger brain think of even more complex ideas?
* Intelligent animals may be able to explain some things from their viewpoints that we had no idea or very little idea about. For example, do animals have religions?
* If there was a fair amount of investing, the costs could be reduced to amounts low enough that a lot of animals could be made intelligent easily, or make them start off with higher intelligence
* The question only states that you could turn on/off intelligence, but if this technology continues to grow, you might be able to increase our own intelligence.
# Neutral
I don't think we'd have any real use for intelligent animals after the first rush of intelligent animals are "turned on". Investment would likely not be as much as required to make the field flourish.
* We wouldn't use them for labour (too expensive)
* They would take a long time to mature (start off at age 3 intelligence)
* Animals may not be able to fit into our society well (We have racists, so I think animalists would also exist)
* Animals would have a huge physical disadvantage for most things (Apes can't actually talk in human language because their voice box physically doesn't allow it and they can't control it as well)
* Artificial intelligence would likely surpass human and animal intelligence in the near future, so super intelligent animals wouldn't be necessary.
* You'd likely not be able to "own" an intelligent animal like you can't own a human.
This is not really being against it, but is not for either. It would just be another science experiment we COULD do, but not necessarily would do.
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After initial fears that this could be a tool used by the very rich to make the rest of the population stupid, later test results showed that mass stupid-ification would be costly and generally unfeasible on the population as a whole.
Assuming that the medical device regulators approve this Uplift technology then the following might happen:
**Pressures to be Smart**
Evolution places a strong emphasis on smarts in humans. Generally, though not always, someone who is smarter will do better than someone who isn't. Being smarter carries a large benefit. "Smart Pills" have been a common scam for centuries but the persistence of the scam indicates that a certain portion of the population desperately wants to be smarter. Given the low capital requirements for this kind of Uplift technology, pretty much anyone can do it. Clinics would pop up everywhere on the Uplift product offerings of medical device manufacturers who would pile into the Uplift market. In a matter of years, anyone who wanted to smarter could be smarter.
**Pressures to be Dumb**
Since everyone has become as smart as they can be, it becomes a punishment to make them stupid again. For certain non-violent crimes, a criminal doesn't go to prison, they just have to endure a dumbing down for a period or permanently.
**Effects on Creatures**
It's a common trope to [uplift animals](http://tvtropes.org/pmwiki/pmwiki.php/Main/UpliftedAnimal) and give them the ability to speak/think/behave on par with humans. Experimentation on animals would continue apace. Scientists of all kinds would have a field day because of the research opportunities provided. For example, any profession that requires diagnosis of a condition in an animal must make inferences about the condition. An uplifted animal can just say "I hurt here and it's this kind of pain."
Translators for each uplifted animals would appear fairly quickly. Dogs and cats will get translation collars.
Legally, uplifted animals will call into question a long precedent of animals as property. If an animal can be made to meet or exceed human intelligence then a strong argument could be made to give them legal 'personhood'.
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The most common response would be "Forget the animals, I want my dose right now!"
For early adopters, the competitive advantage would be extremely great. Financial wizards would be able to manipulate the stock, bond, currency and commodities markets to their advantage, smart criminals could take even bigger scores, smart cops could initially clear the streets of dumb criminals, kids going to elite prep schools will be getting "speed of light" SAT scores and manipulating their entry questionnaires to ensure they get into top rated universities etc. There would be a mad rush to adopt these techniques (possibly even before they are "proven" in controlled scientific studies), and a black market would quickly arise as well (see the movie "Limitless" for one look at how this could play out). Lots of scams would also be done to lure people into paying for ineffective versions of the technique (think of all the "male growth" products on the market today).
As the knowledge of this technique leaks out, eventually the competitive advantage is lessened: you are trying to manipulate the stock market against millions of other super genius stockbrokers, the thug on the corner is a smart as Stephen Hawking, the guy serving coffee and donuts is as smart as Batman and millions of kids with perfect SAT scores are trying to get into Harvard or MIT. The bell curve will reassert itself, just at a much higher level for the median.
Sadly there will always be an underclass of people who were initially too poor to get access to the drug/technique and were left too far behind to catch up (the long left tail of the bell curve) and potentially people who the technique simply does not work on (no technique or drug is 100% effective on everyone, this should be no exception). There will also be a long right tail of the bell curve as well, early adopters, people who this technique works on better than average and people who use their new found smarts to experiment with the technique to amplify their intelligence even more.
So expect a wave of disruption as the effects of vastly more intelligent people start hitting the streets. Like people everywhere, they will be looking first and foremost for their own self interest, so we will not be seeing a serene utopia of Elon Musks building cool things for us, but rather hundreds of Elon Musks competing for market share (although we will benefit from having all kinds of cool stuff to choose from in this market). We will also face predation from super criminals (think of Neil McCauley from Heat meticulously planning how to rob your house and steal your identity), and most social constructs and organizations will start breaking down as people "outgrow" the need for them. A few social organizations might survive as super intelligent Rotarians decide that they will prosper even more as a mutual self help society. Political and legal institutions will be under a great deal of stress, particularly as people use their super intelligence to evade "gatekeeper" functions and avoid regulations and laws which hinder them from reaching their goals. Since I am not super intelligent (yet), I cannot guess as to how they will change, or if they will even survive such a change.
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I am trying to build a planetary system with a maximum number of earth/near earth like planets/moons. What would the maximum number of possible earth like planets be?
I am assuming that some would be free standing and that some would be moons of Gas Giants that were still in the goldilocks zone. All don't need to be exactly like earth but need to be habitable to some degree by large numbers of people.
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I stumbled upon a site a few months back that went into detail on this issue. The site is made by a man who knows what he is talking about. Read the whole thing for more detail on how he came to his conclusions. The question is, is the system artificial, or constructed? If its a single star system you could fit 36 planets realistically. Double that for a double star system. Of course this really couldn't exist natually, the odds are really against it. But as a construct, absolutely.
<http://planetplanet.net/2014/05/23/building-the-ultimate-solar-system-part-5-putting-the-pieces-together/>
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To answer, I split this question into multiple parts (each of which may have subparts):
1. How many Goldilocks zones can there be in a multi-star system?
2. How many orbits can be in a single star's Goldilocks zone?
3. How many planets can be in a single orbit?
For 1, take a look at [this question](https://worldbuilding.stackexchange.com/questions/2657/can-a-planet-realistically-have-multiple-suns). While it does not address the important question directly, what I read in the answers is that there is only one Goldilocks zone - either one of the stars is faint and distant and the planets orbit the other, or else the stars orbit each other closely and the planets orbit their shared center.
For 2, the conservative zone is about 0.5 AU, centered on Earth's orbit, for Sun-like stars. Stars that are somewhat smaller than the Sun have smaller Goldilocks zones (but live longer so life has more time to evolve); stars slightly large and brighter than the Sun (but burn out faster giving less time for life to evolve). Stars with types other than F, G, and K are unlikely to support life.
Because the habitable zone moves during the star's lifecycle (Venus used to be when the Sun was cooler, and Mars will be eventually as the sun gets hotter), I find it somewhat unlikely that more than two orbits could fall into the zone for much of a star's life. However, since both Venus and Mars are *almost* in the zone and we don't really know how much they are hurt by not having a massive moon (which is necessary for tectonics and a magnetic field), I'll say 3 orbits.
For 3, you can consider rocky planets or the moons of gas giants. There *are* stable solutions that involve two planets sharing the same orbit. You *might* be able to replace each of those planets with a pair of planets orbiting their common center of mass while that center orbits the Sun. This way gives you a total of `1*3*2*2=12`. Though I'm not sure if all the doubling is *really* safe so 6 would be a much safer number.
Although gas giants have many moons, they are unlikely to have more than 4 with significant mass, and the presence of gas giants in the inner system invalidates the doubling cheats we used in the rocky case. So just `1*3*4=12`. Note that with gas giants you *do* have a larger goldilocks zone, but this is cancelled out by the fact that gas giant orbits must be farther apart.
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TL;DR: 4 is reasonable, 6 is plausible, 12 is possible.
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If you don't mind long-term instability, a Klemperer Rosette <https://en.wikipedia.org/wiki/Klemperer_rosette>
[](https://i.stack.imgur.com/ld8px.png)
can be extended to any number of bodies
Unfortunately, these are not stable, although it is suggested in the Wiki article that a 12-body version may be stable since each body is at the one of the Lagrange points of two others.
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My question would be a follow up of this question, [Survival without emotion](https://worldbuilding.stackexchange.com/questions/15101/survival-without-emotion),
though not for the same purpose as mentioned in that question. Let me **build up a story and a new world** (*which is a follow up of the existing one*) to facilitate.
Suppose that everything is going as fine as it is now, same old Earth, same old people, and everything as it is. But let us bring an evil guy into the plot. This guy hates humans and human emotions, but he is super-super-super intelligent and can do anything. Moreover, he believes that machines are far more superior than humans and that emotions are a hindrance to our kind. So he makes an evil plan to wipe out every ounce of emotion from this planet, and successfully does it as well. Now with every kind of emotion, whether it be fear, anger, hormones (even them) are wiped out, there's **nothing left but logic (similar to machines) in this new world**.
The difficulty I find after this is that pure logic would have one big-big-big problem/glitch/bug/error/crash/whatever-you-may-call-it: Thinking from a purely logical viewpoint, we have no certain foundational meaning of existence. The universe came out of randomness within vantage of our view: the planets, the galaxies, everything. Consequentially, there will preference to anything? That is to say, everything or every task will have equal meaninglessness. Logically nothing could be preferred over any other task, right? I mean, logic would require us to choose from one of two, one of many, or from yes or no. But since none would be preferred, it's an impossible task.
My question is: **could this scenario ever be realized**? **Is such a world building possible**? Or would this result in a kind of system crash in computer language, or maybe a contradiction in mathematical.
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> **could this scenario ever be realized? Is such a world building possible?** Or would this result in a kind of system crash in computer language, or maybe a contradiction in mathematical.
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I don't believe this scenario can be realized.
The problem is that the question has a faulty first premise: that there is any meaningful distinction between emotions and logic that would enable you to eradicate one from the human experience, while leaving the other in place. But there is no evidence *at all* that this is the case.
The brain is a [neural network](https://en.wikipedia.org/wiki/Biological_neural_network). While there are many subtleties to its operation we haven't even begun to understand, the simple model is that every thought, and every decision, is the product of a chain of neurons making linear classifications: they read a set of inputs and return a yes or no. Billions of these yes or no responses come together to form the complexity of human thought.
There are multiple reasons why this conflicts with the underlying premise of the question:
1. *every input* to the system is important. Hormones generated by the sensation of hunger tip the balance of the yes/no classifier to make you more rash, or "cranky", because there's an evolutionary benefit to doing this in that it drives the whole system to seek food more urgently, for example. If you shut down the ability to feel crankiness, the system is no longer receiving proper input and is partially broken. Anger, passion, etc. are just how we *understand* a set of signals that actually have a deeper meaning. To simply neutralize anger out of hand (as opposed to calming down, where you strategically choose to reinforce alternative inputs *in response to* the anger), you would need to blank the entire set of inputs causing the "overload", discarding valuable information - such as your memory of what made you angry - along with it.
2. neurons are analogue and chemical in nature. As they operate, they change their responses to problems. It might be that they become overworked and need a rest, at which point they start to fritz; more significantly, the basic mechanism of *learning* is that neurons gradually rewrite both their connections to one another, and their decision function, according to the results of the last classification they made. So unlike a computer's logic gates, it is *not possible* for a neuron to reliably generate the same output to the same input time and time again. You *cannot* eliminate boredom, novelty, and so on, because they are fundamental to the basic operation of the system. At best, Evil Guy would permanently rob victims of the ability to learn or remember *anything* new (not just short-term, like Memento: their thoughts would be frozen forever).
3. corollary to the above: there *is* no deterministic mechanism available for the brain to use. When we work out symbolic logic or mathematical expressions, we're much slower than machines because we essentially have to consciously "simulate" a logical layer on top of this fundamentally different architecture, by imagining the "slots" for data and actively choosing to push numbers around (and many of us are bad at this). For a person to actually work completely logically, they'd have to be doing the equivalent of sums on paper to decide what to do next. For *every* action.
This is grossly oversimplified. *Do not assume this is actually how the brain works* (and whether neurons are responsible for all of it, or whether our understanding of them is complete, remains contentious). But the point is the same either way: logic and emotion are artificial constructs, neither of which fully reflects the way a human mind actually works (it is a kind of machine, and everything it does has a reason, but not a deterministic machine like the computers we build to do the jobs it can't). Logic and emotion are just post-hoc *interpretations* of a single deeper principle. Emotion can be described as the situation that arises when a wide set of inputs unify, and become as a driving issue for the whole system to make a choice about.
Of course, that doesn't mean your villain can't try anyway, and discover that his victims simply don't function at all because they can't actually form a thought from one second to the next. That's the reason living in his world would suck.
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Hence, there's no preference to anything?
Logically nothing could be preferred over any other task right?
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False. Logical tasks are preferred over illogical tasks. ;)
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My question could be, could this scenario ever be realized?
Is such a world building possible?
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Can an 'evil guy' create a 'machine' that wipes out 'emotion'? It's theoretically possible... And the subject of more than a few episodes of Doctor Who.
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The difficulty I come across after this is that pure logic would have one
big-big-big problem, glitch, bug, error, crash, whatever you may call it.
Thinking from a pure logical view, we have no meaning of existence.
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Your difficulty is illogical, possibly tainted by the fact that you are an emotion-based creature. This difficulty stems from the assumption that logic-based machines require 'meaning' to validate their continued existence. This is simply incorrect. A computer does not analyze its existence each cycle and decide whether or not to continue processing. It merely continues processing, simply because that's what it does.
A society of purely logical beings, also, would merely continue processing. There is no need for 'meaning' or 'purpose' in such a society, other than, perhaps, the preservation of that existence, driven by biological impulses.
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# The Importance of [Hormones](https://en.wikipedia.org/wiki/Hormone)
Hormones are really, *really* important. Sure, there are ideas that hormones are the root causes of emotions, and that is bad, but emotions serve a very important role. Evolutionarily, we can blame emotions for carrying us through to today. Fear helps us respond better to life-and-death situations. Happiness signals "what just happened is approved by our bodies" and anger helps us preserve boundaries, including avoiding bodily harm.
Hormones themselves regulate many super important functions in the body. Good luck controlling your water/salt balance and not exploding your cells without [steroids](https://en.wikipedia.org/wiki/Steroid_hormone). This is also not to mention your circadian rhythm, immune system, controlling hunger, and [myriad other uses](https://en.wikipedia.org/wiki/Hormone#Effects). A person without hormones is soon a *dead person*.
This means your premise cannot be realized. Your world would be forever stuck in fantasy. You cannot have a society of humans without hormones.
# The Equality Catastrophe
You will simply need to provide an axiom for your perfect-logic flesh machines to go off of. One could say "cyclical biological processes" (eating, breathing, reproduction) are the purpose of life. Your society would then continue on, focused on these things.
The purpose of life is one of those things that everyone very likely must come to grips with, hormones or no. So really, you need to give your logic-only people something to do, otherwise they may fall into your equality catastrophe. You could also find evidence that this existence is not just random, and the logical thing to do would be to respond appropriately to this new information.
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> Thinking from a pure logical view, we have no meaning of existence. The universe came out of random, the planets, the galaxies, everything came out of random. Hence, there's no preference to anything? That is to say, everything or every task will have equal meaninglessness. Logically nothing could be preferred over any other task right?
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We still have senses. We'd still feel pleasure or pain, be able to taste the difference between good and bad food, or enjoy a warm summer breeze or a sunset.
So we'd have preferences, we'd want things that feel good and avoid things that feel bad. The problem we'd run into is that emotions are like lubricant for civilizations - there's a reason we evolved with them.
Large-scale, a lack of emotions will likely reduce conflict. You're less likely to be able to convince people to go to war for an ideal, or to launch a nuclear bomb when logically that means it will eventually kill them as well. And why bother with genocide? On the other hand, it's likely that the economy will collapse, as people will stop making emotionally-driven purchases.
Small scale we see other issues. Families will self-destruct unless having children is somehow objectively beneficial to parents. It is possible that a lot of personal gratification crimes, like theft, rape, or murder, will skyrocket. On the other hand, people might tend to view them more transactionally without emotional context - so maybe instead of those increasing, we just repeal laws and say, make prostitution legal.
Long-term, I think the lack of population growth will kill us off. There just won't be enough people who have kids in this scenario to maintain a civilization. It is possible that those who do want kids - for whatever reason - will eventually re-populate, but that will take at least hundreds of years, if not thousands.
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An enormous alien monster lands on Earth and goes on a rampage. He gets knocked out by a nuclear bomb, and falls into a temporary coma. The U.S. government decides to transport his body in a secure location... but can it be done?
What's the maximum mass and size of a giant alien monster which we could transport by land and/or by water?
Notes: You can't make the approximation that his mass is proportional to his size, because the big alien monster is made of exotic matter (which also explains why the nuclear bomb didn't completely obliterate him), so his density can be much higher or much lower than ordinary matter. And no, you can't slice his body into many pieces and transport each piece separately: his body is indestructible.
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This is much easier done over water -- [heavy-lift ships](http://en.wikipedia.org/wiki/Heavy-lift_ship) can move objects on the order of tens of thousands of tons routinely, and the [largest examples of this type](http://en.wikipedia.org/wiki/Dockwise_Vanguard) are able to handle objects in excess of 100,000 tons combined with immense bulk, up to and including an oil-platform-sized monster. Of course, you can also attach buoyancy devices to the beast until its seaworthy, then tow it with whatever quantity of towing vessels the thing's mass necessitates.
Over land, though -- such moves are far more difficult. Trains are the dominant industrial heavy-haulers of this day and age; no road-going vehicle can move the sheer amount of tonnage a modern locomotive consist-set can haul (well in excess of ten thousand tons, up to the thirty to fourty thousand ton range depending on how extreme your distributed power setup is). However, you're limited by the railroad loading gauge and by axle loading; this limit means that your monster has to fit within a 13-14' or so wide (up to perhaps 17' in the most generous of areas) by 23' high box, and to a practical maximum of a few hundred to a thousand tons with a well or [Schnabel car](http://en.wikipedia.org/wiki/Schnabel_car) and idlers; Schnabel car moves also limit the length to somewhat over 100' in order to avoid excessive in-train forces when negotiating curves.
If non-road-going vehicles are allowed, a [crawler-transporter type vehicle](http://en.wikipedia.org/wiki/Crawler-transporter) can be used. These can handle several thousand tons of load, but would be limited to a dedicated, prebuilt crawlerway, and also to sizes in the 125' square range. If that's not an option, but large roads *are* available, the closest thing to a crawler-transporter that's still somewhat roadable would be a [self-propelled modular transporter](https://en.wikipedia.org/wiki/Self-propelled_modular_transporter) system. On-road load-limits for these range well into the hundreds of tons, and vehicle lengths and widths are limited by the design of available roads, but generally are smaller than crawler-transporters, especially widthwise. SPMTs are also agonizingly slow-moving compared to just about any other mode of transport discussed here, and transport over road subjects you to stringent height limits (13-14' unless you get an overheight permit in addition to the overwidth/slow-moving-load permitting you'd need for roading a SPMT, and even with an overheight permit, I doubt you could achieve more than 15-18' of clearance save for short distances on the order of a typical house move.)
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I have one option to add to Shalvenay's excellent answer - airships.
If there was time to build it a custom airship can haul a massive load slowly to anywhere in the planet.
Heavy lifting airships currently in design and prototype stages can each haul 500 tonnes. It's possible in fact that with a suitable frame for the creature a group of those could work together to lift even more.
For example here is a 66 tonne airship, the prototype is currently operational:
<http://jalopnik.com/5980630/new-colossal-airship-makes-successful-test-flight-and-reminds-us-how-much-we-love-airships>
Here is another company talking about 50, 250 and 500 tonne airships although obviously it may never actually come to pass:
<http://www.varialift.com/>
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There's virtually no upper limit to what we could transport by water. If he floats you just tow him. If he sinks you attach floatation to him until he floats then you tow him. The capacity of a ship doesn't enter into this as you can bring a lot of ships into the picture. Grab the oceangoing tugs, grab the icebreakers (they're way overpowered for their size), grab the major warships of the world (warships are built to go fast, they are likewise overpowered for their size.) You don't need to be able to go fast, just fast enough to overcome any ocean currents. 5mph is enough to overcome any sustained ocean current.
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it would not be a problem, not at least a technical problem. Please refer to the [accepted answer to this question](https://worldbuilding.stackexchange.com/questions/210149/what-kind-of-war-would-lead-to-ultra-heavy-tanks-being-useful?noredirect=1&lq=1) about large ware machines .. the answerer refers to the largest heavy lift machines that we have made, any of which would handle your monster
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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.
Given Earth's current level of technology, space- and ground- based astronomical tools, etc., to what extent would it be possible to locate the Milky Way from a somewhat distant galaxy, say, in another nearby supercluster?
I know we have a reasonable mapping of our Local Group of galaxies, the Laniakea Supercluster and the rough large scale structure of the universe. But would it be possible for a group of people using current technology to locate themselves in the universe over the course of ~100 years and to locate the Milky Way specifically? Or would it be more likely they would have no idea where in the universe they found themselves and would not be likely to find out for a very long time?
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# Detecting Galaxies
Let's look at the example of [UDF 423](http://en.wikipedia.org/wiki/UDF_423), one of the brightest galaxies in the Hubble [Ultra Deep Field](http://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field). It has an apparent magnitude of around 20, and an estimated distance of 7.7 billion light years (well outside of our supercluster). This gives it an absolute magnitude of somewhere around -21.8, making it only around three times brighter than the Milky Way (at magnitude -20.9). Since it's clearly resolved in the UDF, we can treat that as a good estimate for the level of detail we'd need to achieve in our observations to see the Milky Way directly.
The instrument that Hubble used to capture the UDF is the [ACS](http://en.wikipedia.org/wiki/Advanced_Camera_for_Surveys) (Advanced Camera for Surveys), with a resolution of around 0.05 arcseconds. The main instrument on JWST is [NIRCAM](http://www.stsci.edu/jwst/instruments/nircam/nircam-glance), with a similar resolution and sensitivity.
The exposure for which the sensitivities are calculated is around 10,000 seconds, and the field of view is 4.4 arcseconds square. This means that a single JWST would take around 3000 years to scan the whole sky at that resolution.
## Speeding it Up
Of course, we only need to find a couple galaxies that we recognize. Due to the huge number of them, the probability that we see a familiar one is actually pretty high. Once we are confidant of the location of one or more, we can start concentrating our search on a specific sector of sky, and the speed at which we start locating galaxies will be superexponential.
## Recognizing Galaxies
As "BrettFromLA" says, we likely wouldn't recognize galaxies by visual comparison, especially since many would appear in different orientations (one which was once edge-on could now appear face-on). Galaxies would instead be matched by their brightness and spectra. This only gives us a fuzzy match, but
# Other Sources
Although pulsars make good candidates for locating ourselves (since they are uniquely identifiable by their period) they are generally too dim to be visible billions of light years away. We can look at quasars, which do not have as clear identifying features, but are significantly brighter.
The [Sloan Digital Sky Survey](http://en.wikipedia.org/wiki/Sloan_Digital_Sky_Survey) identified most known quasars over around 35% of the sky, and took just ten years to complete. A network of telescopes could cover the whole sky in just a few years. Again, the quasars would be matched by their spectra. After our location is pinned down by the quasar survey, we can use spaceborne telescopes to locate the Milky Way.
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Identifying the Milky Way by its appearance alone would be tricky. It's not an exceptional galaxy. Also, as far as I know, we haven't mapped a lot of it because we simply can't see through the dust and the dense galactic center to see what's on the other side.
However, if our travelers can rely on our current technology AND on our current knowledge of the mapping of the known universe, it should be doable. They first map the large celestial bodies around them. Then they "fit" that map into their existing map of the known universe. Based on that "fit", they will know where they are, and of course they'll know where the Milky Way galaxy is.
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The rag-tag group of natives and tourists somehow survived for a week on [the manor by the cliff](https://worldbuilding.stackexchange.com/questions/13779/how-close-is-too-close-for-a-human-habitation-to-be-near-an-erupting-volcano), while the volcano still spits lava and pyroclastic clouds all around.
Just before the last cell tower near the manor broke, a survivor managed to post on social media a photo of the group on the manor, so the general public is aware of survivors. Some of them are from wealthy and influential 1st world families (USA and Europe), so there is pressure to mount a rescue operation.
They have no other means of communicating with the external world, but the UN, USA and EU authorities still tell the media, one month later, that the search and rescue for those survivors goes on strong.
The fictional country that island belongs to is some 1200km north-northwest of Guam, and is a developing country, and have to deal with all sorts of other problems in neighbor islands, so rescuing these foreigners is not their priority.
The US government approved a rescue operation by "any means necessary" (so it says on the press release), but still it is suffering delays.
What possible reasons published by the authorities could justify the delay of this rescue operation by several months?
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**Volcanic ash cloud!**
**How do I know?**
**It happened in the past!**
As a matter of fact, in 2010 Eyjafjallajokull (a volcano in Iceland) erupted and disrupted air travel across Europe and the Atlantic. For weeks. I would imagine that if this is a small and mostly isolated island in the Pacific the only way to get there without air travel is by boat. As history has shown that is considerably longer than an 18 hour flight.
Then again, why would they send help at all? If this was a big enough eruption and it causes a drop in global temp it will send society into chaos. All governments would have better things to do than rescue islanders who are probably already dead.
I mean, even with a few members of influential families on the island, they are probably already presumed dead and therefore chance of imminent rescue would be nill.
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A Hurricane is sitting on top of the island! Beautiful visuals! It's a Hurricano! Challenge the science wizards on this site to explains how all the ash and heat of the volcano could somehow make the hurricane become stationary and permanent with its eye directly over the volcano.
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1) Because they don't want some of them (or all of them) rescued? (They are believed to have witnessed something the government doesn't want known?)
The government tries to stall while finding a solution for that (having to rescue them because of international pressure and - you know... - morals) They may try to fake a rescue when in fact trying to kill em off, or to trick an other island nation to rescue them and attack that rescue "thinking" it was just that nation's armed forces helicopter and not a rescue.
2) Volcano won't stop and dishes out to much ash and rocks to safely approach the island by air, and by sea is complicated because the surrounding island nations will not let them approach but won't rescue themselves because the U.N. has denied them access to the island and they've yet to lift that ruling, but allowing them would implicate the island being claimed by them or something like that.
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**Unknown Location**
The world is *big*. Even "tiny" islands can be incredibly large when you're looking at manual search and rescue. If the eruption is continuing, it will make satellite or air surveillance nearly impossible, and roads largely unusable. So now you're searching on foot.
As long as the social media post didn't include an exact location, the authorities will find it difficult and time consuming just to find the people. Especially if exterior damage/ash makes it hard to tell which manors are simply abandoned vs the one they're holed up in, that means they have to check them all individually, while staying in protective gear and keeping supplied since they can't live off the land.
Another factor could be someone writing off their actual location as already searched (either through a simple mistake or incompetence) meaning the authorities are concentrating their efforts elsewhere.
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The island moved by several hundred miles (huge plate shift) not only throwing it off the active volcano (so no smoke plume to follow) but preventing authorities from finding it at all. Meanwhile, the volcano continues to spew ash, smoke, and dust which hampers satellite and high flying search operations, meaning everything is done in dim to dark conditions, close to the ocean where the search areas are small and time consuming.
Further, some other minor crisis is going on requiring continued maintenance or attention, pulling away resources that would normally be used for this type of operation.
Geologists were aware of earthquakes and tremors, but it takes some plucky researcher to posit a plate shift, and then weeks for her to convince people that it may be the reason they can't find the island.
Further, since the volcano is still spewing, but the island is clearly no longer the same, many posit that it sunk or crumbled down, rather than simply moved elsewhere. They are conducting a half-hearted mission, no longer hoping that it will be rescue, but merely find answers.
[Answer]
Putting together stuff from a bunch of other discussions plus some of my own ideas.
Based on the discussion in your other thread, if the 'valley' diverting the lava flow from the survivors was approximately C-shaped, then these people could essentially be on a 'island' in the middle of the lava flow. That would cut off any land or water-based access as long as the lava keeps flowing. About the air-access, the (presumably shifting) ash cloud (a la Eyjafjallajokull) would make it too risky to fly until the volcano stopped completely. I think the air access would be advised against even if it was mostly clear, since I think even fine ash particles can mess up aircraft engines. This line of reasoning would allow the survivors to have mostly clear air to breathe, while still preventing rescue.
[ And this might help : <https://en.wikipedia.org/wiki/Volcanic_ash_and_aviation_safety#Immediate_hazards_to_aircraft> ]
[Answer]
I think the above volcanic ash option is the best. It's a large island, they aren't sure exactly where everyone is, and there is ash everywhere.
As another option, try politics. Perhaps to get a rescue operation flown in they would have to fly through the no-fly zone of a country, and they can't get permission to pass through it? Perhaps the country that has the volcano eruption explicitly refuses help for political reasons. If the country is developing it may not have the means, or suicidal tendencies, to shoot down a humanitarian rescue chopper. However, if they are developing due to presence of oil or other natural resource they MAY be able to threaten to cut off resources to first world countries that don't respect them.
If you claim that only the few dozen folks are in danger, perhaps their on an island that is mostly uninhabited, then it becomes a matter of a few lives vs major political fights. Perhaps the country with the volcano claims that they can rescue the people in trouble and the government needs to 'prove' they don't need help from the big first world countries, but the local government actually lacks the resources to mount a rescue. Meanwhile their stubborn insistence on proving they don't need help, and threats to cut of oil and otherwise punish any country that does provide aid prevents or delays first world nations from helping.
Politically the first world nations would say they are respecting the wishes of a sovereign nation, not giving in to demands to keep the oil flow. They may be taking other actions, like organizing a rescue that works *with* the local nation's government in a way that lets that nation save face.
To make the idea work well I would imply that the US and first world countries don't think that those trapped are in immediate danger, and thus think they can afford to take some time in playing the politics game. Maybe they underestimated the rate at which lava is flowing and misjudged how close the trapped persons are from the actual lava flow? Perhaps the local government is intentionally feeding mis-information as part of their saving face (yeah we haven't rescued anyone, but not because were incompetent, they just aren't in danger so we don't need to do anything crazy). Between the misinformation, and the ash blocking out satellites (plus, we wouldn't have spy satellites over unimportant regions of the world, so we don't have nearly the bird's eye view you may assume) the first world countries simply don't get how dangerous it is for your survivors.
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[Question]
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**The Settings:**
A pod of nanobots stranded on earth-like barren planet orbiting sun-like star. Assume no life form has formed on the planet, and nanobots popuate the planet.
1. Could they evolve complex ecology (techno-sytem in place of ecosystem) where plant-like and zoo-like species composed entirely from evolved nanobots (instead of biological cellular life)?
2. Assuming Nanobot's considerably efficiency at utilizing energy for manufacturing more of them, modifying future generation for better survivability, and assuming that they were quite intelligent as a swarm, is it possible that they evolve at extremely faster rate?
3. If a sapient species of their life line do evolve, is it possible for them to utilize other "life" of their own line (composed of evolved nanobots) in form of biotech, like intentionally evolve a species to a specialized breed for their own purpose, like transport, air transport, bioships?
**Additional notes:**
1. Evolved multicellular (multinanobots?)-like species has their cell (nanites?) capable of communicate range limited to a single individual
2. Brain-to-brain communication with different individual (another colony of specialized nanites?) could be done via general purpose (imagine usb port) wiring slots (kinda similar to James Cameron's avatar nerve-tip).
[Answer]
Your point 2 answers the question: if they are capable of making modifications to themselves, then they can evolve, and if they can evolve, then they will begin to specialize in order to take advantages of ecological niches.
They will also have another force driving evolution, essentially ecosystems are like markets (or markets like ecosystems if you will) and the various organisms will be attempting to maximize their outputs and minimize their inputs. These "market forces" will drive specialization, develop predator/prey relationships as well as parasitism and symbiosis; all the things we see in our own ecosystem.
As machines, I will assume they operate at a factor of up to 1,000,000X faster than similar biological systems (the ratio between electrical and electrochemical signal speeds), and as nano systems, they can obviously extract resources from the planet much more quickly and efficiently than macro scale beings like ourselves. This leads me to believe that their evolution, branching out into species and establishment of an ecosystem will be far faster than Earth (the 3 billion year period when Earth was essentially covered by pond scum will be over in a few thousand years, and the "Cambrian Explosion" will take hours or days when it happens.
The only thing that will make this scenario difficult is the sheer speed of evolution will lead to extremely unstable ecosystems, with mass extinctions and wild changes to the ecosystem (and possibly climactic and even geological changes due to the actions of the nanomachines) being common events.
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How dense would the atmosphere of a theoretical planet have it be, in relation to Earth's atmosphere, to fly with, say, a 10 to 15 foot wingspan?
Math is acceptable and encouraged, and a set of artificial wings is assumed. I'm thinking an incredibly tough (fictional) plant fiber spread over a carbon composite frame. When not in use, it could be folded into a school backpack-size with convenient support straps so that it can actually be WORN like a backpack. It can also be taken completely apart to be stored in a large pack with other equipment. It's got a joint system for flapping, but not with all the minutiae of a real bird wing, so you'd have to angle your arms on the upflap. It will also have footholds for when in flight.
[Answer]
This is a quick answer: The Lift Equation is:
$$
L = C\_L \* (1/2) \* \rho \* V^2 \* A
$$
Where $L$ is Lift in Newtons, $C\_L$ is the lift coefficient of the wing, $\rho$ is the air density in kg/m^3, and $A$ is wing area in m^2.
$\rho$ is ~1.2 kg/m^3 between mean sea level and 2 km MSL on earth as we know it. At 15 ft (~5 m) wingspan and a crude aspect ratio of 3 (which is low, a higher the aspect ratio of 10 would be better), A (area) is about 8 m^2. A human at 60kg is ~600N of lift required. Let C\_L be about 1.0, best case, but more likely around 0.6 for this wing, for the forward-flight cruise condition. Second part of this is determining the power required for flight, which is probably 80 Watts max continuous for a typical person. $Power = Force \* Velocity$, and in this, power is a constraint, the force and velocity being free variables. The force being provided is to counter drag, which we can let be about 20% of the lift force worst case, ~10% better case.
I'll assume:
$$
L = 600N, C\_L = 0.6, A = 8 m^2, P = 80 W, D=0.1 \* L = 60 N
$$
This yields $600 = 0.6 \* 0.5 \* \rho \* V^2 \* 8$, or $V = \sqrt{600/(0.6 \* 0.5 \* \rho \* 8)}$
The second equation, $P < F \* V$, can have the above spliced into it:
$80 = 60 \* \sqrt{600/(0.6 \* 0.5 \* \rho \* 8)}$
Solving for rho, we have $\rho > 140 \: kg/m^3$
This is 30 times the density of the atmosphere of Titan at its surface, and 1/7th the density of water. Of course, if you tweak numbers, you can probably get this much lower, say, by putting drag to 5%, assuming C\_L at 0.8 to 1.0, and increasing the wing area. You may want the wing span to be a bit higher, say, 8 to 10 meters (26 to 32 feet), which allows for more wing area and increases the aspect ratio, which makes your wing more efficient.
A few things I'm skipping are the Reynolds numbers, Oswald efficiency, and how viscosity and compressibility would work.
Bonus: Here is a website I found a while ago that shows how you could do flapping flight with not-to-distant-future technology: <http://www.dcgeorge.com/>
References:
<http://en.wikipedia.org/wiki/Human_power>
<http://www.lpl.arizona.edu/~yelle/eprints/Yelle97b.pdf>
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After being told about hemianopsia (visual neglect) in an [answer to another question](https://worldbuilding.stackexchange.com/a/10510/6986), I started wondering if I could apply the same idea to artificial applications, such as securing information or hiding things.
Information has always been something we as humans have tried to control. Governments and companies are in an arms race with other governments and companies and third parties to develop better defenses. **Is there some manner of artificial construct, or set of constructs, that would enable an entity to control what objects or information is physically seen by an arbitrary individual?**
For example, Franklin has been cleared by the government to enter the Blue Room. He can enter the building with the Blue Room, go to the hall with the Blue Room, stand in the hall with the door to the Blue Room, use his id to unlock the door, and enter the Blue Room without any problem. The spy behind him, Clemont, who isn't cleared to enter the Blue Room, can follow Franklin into the building and to the hall, but he's too far behind Franklin to see where he went and doesn't see the door to the Blue Room.
For another example, Franklin is cleared by a company to watch streaming data on a certain computer screen. When he looks at the screen, from anywhere the screen is visible, he can see all the data streaming at that time. Clemont, however, who isn't cleared for this either, could press his face against the screen and see only his reflection on what appears to be a disabled device.
My first idea to support this would be a device that indiscriminately applies its effect out to a certain distance and an implant that neutralizes it. Thus, no one notices anything out of place, at least until an uncleared person watches a cleared person walk through a wall or simply vanish.
[Answer]
Running with your second example with the implant, I could see this being done with pretty basic crypo. Instead of a blank screen, the screen would need to appear to have something on it, just nothing human readable. Static would work, or something that looks like the falling numbers Matrix screen. As long as it continually changes without appearing meaningful. Franklin's implant would have the key to creating meaning from the visual noise, and could perhaps directly affect his perception, replacing the static with the decoded information.
The unfindable door is trickier. But we could go low-tech, and just make a door that doesn't look like a door. It would just blend in with the wall. Then, we throw in some high tech sensor to have the door open when Franklin is in front of it. If Franklin still has an implant, the implant could impose an image of a door on the wall at that spot, so that as far as Franklin can tell, it's an ordinary looking door with a motion-sensor opener.
[Answer]
Another answer similar to the one above but still distinct: polarized light. If the cleared Franklin is given a set of glasses carefully polarized to the appropriate spectrum of light (or, if you want to get trickier, it's synchronized to the changing polarization of the source of secret data) his eyes will perceive the pure data, while clever Clemont will see a mass of static from the other non polarized sources. If the door has no obvious features but can reflect a polarized light source differently than other walls, then the door would stand out to someone with the right glasses, while everyone else would see indistinguishable walls.
[Answer]
The simplest way would be to have implants in everyone's head. Those would interfere with the connections within the brain and anything that you weren't cleared to know about would be blocked from recognition.
So your eyes would see the door, your brain would register it...however the brain would be unable to accept or grasp or process it as anything important. The fact that the person you are following went through the door would just not make it from the visual and memory area to the decision making parts of the brain.
Depending on how this modifies connections and long term memory you might have the interesting scenario where someone's chip malfunctions and suddenly they not only start seeing things they should not - but they remember all the things they saw in the past!
[Answer]
I would go the opposite path TimB did, and **make the device external, and on-by-default, off-by-design. Even so, it would not stop a determined spy with electronic means of surveillance.**
***The visual neglect inducer detects all incoming foot traffic, maps the location of the passers-by brains, adjusts the network of electromagnetic field generators (hidden in the walls and ceiling) to 'blind' the awareness of all passers-by in regards to the existence of the door. It accomplishes this by messing with the functioning of the visual processing neural centers that deal with information integration in preparation for conscious awareness downstream***, in a way similar to that described [in my previous answer](https://worldbuilding.stackexchange.com/questions/10508/science-behind-a-naturally-invisible-creature/10510#10510).
With hardened [IFF transponders](http://en.wikipedia.org/wiki/Identification_friend_or_foe) in authorized personnel, you can selectively exclude friendlies from the effect, and thus you can get your [Platform $9 \frac{3}{4}$ effect](http://en.wikipedia.org/wiki/Places_in_Harry_Potter#Platform_Nine_and_Three-Quarters). The computer terminal you mention would not even be visible to the interloper.
However, things quickly become more complicated when you introduce nonbiological surveillance. While a normal video recorder can be scrambled into uselessness by a field, Clemont is KGB-trained, and has access to decent, hardened hardware, or even mechanical devices such as old-fashioned cameras that are not vulnerable to scrambling.
Additionally, the modulated fields that induce the visual neglet are themselves susceptible to detection. So if you don't know where in the building the secret lab is located, all you have to do is walk around taking pictures every few steps with a mechanical micro-camera while a field detector scans for anomalies. Back at the base, you can compare the micro-camera results with your recollections and cross-reference with any anomalous field measurements.
From Clemont's perspective, the problem still remains that even with knowing where the door is located, your brain refuses to see it. Perhaps placing Clemont (or just Clemont's head) in a faraday cage, such as a modded biker helmet, or even a metal-lined baseball cap, might degrade the visual neglect inducer's effectiveness sufficiently that he would be able to notice the door. Presumably, the breach by an IFF-nonfriendly would still trigger all sorts of alarms, so it's unclear that the increased security of building a visual neglect inducer is worth the hassle, but it's rather cool none the less.
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I have been working on the setting for a hard speculative biology/evolution project that for now will simply be referred to as the Gemini Project, and the main issue I've been having is whether or not complex life comparable to that seen on Earth in the last ~100 million years could emerge and evolve naturally on moons orbiting a gas giant. Life on Earth has shown itself to be extremely resilient, and can exist in relatively extreme environments, so it would be reasonable to assume that it could exist beyond completely Earth-like conditions to some degree.
---
**Leda and the Twins:**
**TZ343-B/Leda** is the gas giant within the habitable zone that the twin moons orbit, and its mass, radius and gravity are 1.078M♃ / 343M⊕, 1R♃ / 11.210R⊕ & 2.725g / 26.723m/s²
**TZ343-B-1/Castor** and **TZ343-B-2/Pollux** are both approximately the same approximate mass, radius and gravity: 2M⊕, 1.202R⊕ & 1.385g / 13.582m/s². They both orbit Leda, and are tidally locked in their orbits; meaning that their orbital periods and diurnal cycles are practically one and the same.
---
**Other Issues:**
The other issues I am having are deciding the exact mass of the parent K-class star, **TZ343-A/Tyndarzeus**; the semi-major axis of Leda; and the semi-major axes/orbital periods/diurnal cycles of the moons, although Castor should have an orbital period/diurnal cycle somewhere between 20 and 48 hours long.
The setting also assumes that [superhabitability](https://en.m.wikipedia.org/wiki/Superhabitable_planet) is real/true, and conforms to it as best as I understand it.
---
**Overall, could carbon-based life emerge and evolve under such conditions from what we understand?**
[Answer]
Scientists have done a lot of thinking in recent decades about the possibility of more or less Earth like life, using liquid water, on very large moons of giant planets in other solar systems.
So a good place to start getting an answer would be scientific papers on the subject.
Like this one:
<https://arxiv.org/ftp/arxiv/papers/1209/1209.5323.pdf>
And on pages 3 to 4 it discusses the possible mass range for a habitable planet, moon, or other type of world.
>
> A minimum mass of an exomoon is required to drive a magnetic shield on a billion-year timescale (Ms ≳ 0.1M⊕,
> Tachinami et al. 2011); to sustain a substantial, long-lived atmosphere (Ms ≳ 0.12M⊕, Williams et al. 1997; Kaltenegger
> 2000); and to drive tectonic activity (Ms ≳ 0.23M⊕, Williams et al. 1997), which is necessary to maintain plate tectonics and
> to support the carbon-silicate cycle. Weak internal dynamos have been detected in Mercury and Ganymede (Kivelson et al.
> 1996; Gurnett et al. 1996), suggesting that satellite masses > 0.25M⊕ will be adequate for considerations of exomoon
> habitability. This lower limit, however, is not a fixed number. Further sources of energy – such as radiogenic and tidal heating, and the effect of a moon’s composition and structure – can alter our limit in either direction. An upper mass limit is
> given by the fact that increasing mass leads to high pressures in the moon’s interior, which will increase the mantle viscosity
> and depress heat transfer throughout the mantle as well as in the core. Above a critical mass, the dynamo is strongly
> suppressed and becomes too weak to generate a magnetic field or sustain plate tectonics. This maximum mass can be placed
> around 2M⊕ (Gaidos et al. 2010; Noack & Breuer 2011; Stamenković et al. 2011). Summing up these conditions, we expect
> approximately Earth-mass moons to be habitable, and these objects could be detectable with the newly started Hunt for
> Exomoons with Kepler (HEK) project (Kipping et al. 2012).
>
>
>
Thus it claims that the upper limit for a habitable world is roughly approximately about 2 times the mass of Earth, which is about the mass you have decided upon for your two moons Castor and Pollux.
So possibly you might want to consider reducing the masses of your moons a tiny little bit incase those calculations are correct and the upper mass limit for a habitable world is approximately 2 times the mass of Earth. On the other hand you did write that your story assumes superhabitability of large terrestrial type planets much larger than Earth.
You write:
>
> Leda and the Twins:
>
>
> TZ343-B/Leda is the gas giant within the habitable zone that the twin moons orbit, and its mass, radius and gravity are 1.078M♃ / 343M⊕, 1R♃ / 11.210R⊕ & 2.725g / 26.723m/s²
>
>
> TZ343-B-1/Castor and TZ343-B-2/Pollux are both approximately the same approximate mass, radius and gravity: 2M⊕, 1.202R⊕ & 1.385g / 13.582m/s². They both orbit Leda, and are tidally locked in their orbits; meaning that their orbital periods and diurnal cycles are practically one and the same.
>
>
>
So Leda has 1.078 the mass of Jupiter in 1.0 times the radius and thus volume of Jupiter, and so Leda has 1.078 the average density of Jupiter.
Giant planets much more massive than Jupiter don't get much larger in volume. Instead their increased gravity compresses their matter more and more and they get only a little larger than Jupiter and can even get smaller than Jupiter. I don't know the formula, if any, for calculating the radii of gas giant planets more massive than Jupiter. I hope you have checked to see whether Leda has the correct radius for its mass.
Jupiter has a surface gravity 2.528 that of Earth, and Leda has a surface gravity 2.725 that of Earth, which is that of 1.077 that of Jupiter. According to this online escape velocity calculator:
<https://www.omnicalculator.com/physics/escape-velocity>
Leda should have an escape velocity of 61.88 kilometers per second, 5.53 that of Earth, while having a surface gravity 2.725 that of Earth. So clearly the surface gravities and the escape velocities of planets do not vary in the same proportion.
The data you give on the twin moons are:
>
> TZ343-B-1/Castor and TZ343-B-2/Pollux are both approximately the same approximate mass, radius and gravity: 2M⊕, 1.202R⊕ & 1.385g / 13.582m/s². They both orbit Leda, and are tidally locked in their orbits; meaning that their orbital periods and diurnal cycles are practically one and the same.
>
>
>
So each of the moons has two times the mass of Earth within 1.202 the radius of Earth and thus 1.7366544 the volume. Thus each moon should have about 1.1516 the average density of Earth.
Of course all large worlds compress the matter inside them. I don't know how to calculate whether your moons have, or less, or the same, average density as they would have if they have twice the mass of Earth and are made of the same mixture of materials Earth is.
The moons Castor and Pollux have twice the mass of Earth and 1.202 times the radius, so their escape velocity should be 14.43 kilometers per second, 1.29 that of Earth. Since their surface gravity is 1.385 that of Earth, this is another example for world builders that surface gravity and escape velocity vary in different proportions and must be calculated separately using different formulas.
You wish to decide:
>
> and the semi-major axes/orbital periods/diurnal cycles of the moons, although Castor should have an orbital period/diurnal cycle somewhere between 20 and 48 hours long.
>
>
>
Since you give the masses of Leda and castor, it is easy to calculate the semi-major axis to go with a specific period.
Using this orbital period calculator:
<https://www.omnicalculator.com/physics/orbital-period>
I found that an arbitrary semi-major axis of 1,000,000 kilometers gives an orbital period of 6.202 days or 148.84 hours. Trying a semi-major axis of 200,000 kilometers give 13.312 hours. 300,000 kilometers gives 24.456 hours.
To be continued.
[Answer]
As others have said, it is hard to answer since we do not have any reference other than Earth. If an exoplanet is not like Earth, there is no good reason to believe it would emerge any, let alone Earth like, life.
Ultimately, i think you are asking the wrong question. Presumably you want to write a story / spec evo project, like will you just not do it if we tell you "Nah not realistic" ? With every single piece of media there is suspension of disbelieve. There was a great meme on this lemme find it;
[](https://i.stack.imgur.com/b0dpy.png)
I presume your goal is to have some kick ass spec evolution going on, so it is fine to just assume life developed. Similar to how it is ok that 99,9999% of so called hard sci fi novels ignore the fact Fusion reactors produce radiation and are probably garbage for thrusters.
So my answer would be, yeah just go for it. These details are not important, you want a certain environment to explore the evolution of life, just do it.
I think the much better question to ask is wth is going on in your planetary system. Two Earth sized moons around a Jupiter wannabe ? Not if physics has anything to say about it. Moons form through accretion, or get captured. Accretion is well documented to have a distinct relation between the mass a planetary disk can form, compared to the mass of the parent planet. That mass ratio is about 13000:1 if memory serves me correctly. So for every 13000 kg of Gas giant, you get 1 kg of moon. This would imply your Gas giant has a mass of around 13000 Earths, or 4 Jupiter's. Which is more of a little baby Star.
I can believe one Earth sized moon revolving around Jupiter after being captured, but then there are no other moons. If you took Earth and placed it around Jupiter, all other moons would be gone very quickly.
[Answer]
I agree with some of the other comments and answer, no one knows where life can form in the universe so just go with it.
On that note though, there are some conditions you can add to make your moons suitable to life to the best of our knowledge.
Habitable zone. there is a habitable zone both of the galaxy and of the solar system. This means that you're moons should have water. Early life should also create an ozone.
An active core that causes tectonics and creates a magnetic field. Tectonic activity supposedly increases the chances of life (hydrothermal vents, heat, churning of minerals to the surface) and magnetic field would protect life from dangerous space stuff.
Two problems I can think of two the best of my knowledge since I'm not an astronomer or something:
Radiation - To the best of my knowledge Jupiter emits a lot of harmul radiation which is harmful to life. not sure if this is a problem with all gas giants or if a magnetic field would protect from that.
Meteor impact - again, to the best of my knowledge, one of the reasons the inner solar system is relatively calm meteor-wise is because jupiter's high gravity sucks them in. so if your moons are being bombarded by meteors all day that might be an issue. Maybe add a larger gas giant farther out in the solar system?
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[Question]
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## Context:
I've got an asteroid belt analogue situated between a Gas giant and a Super-earth. I knew about resonances, so I started calculating them and placing some of them in the belt, especially ones that would be convergent between the giant and the super-earth, to know where the gaps would be present. Then I realised that resonances also tend to create stable orbits, like the orbits of Galilean Moons.
## Question:
What dictates whether an orbital resonance causes a stability of the orbit (like the Galilean Moons) or disruptions of the orbit (like the Kirkwood gaps)?
[Answer]
TL;DR: Each resonance can be associated with a certain region of space within which it can affect objects. You can calculate the size of this region from the properties of the resonance and the orbits lying near it. If the regions from two neighboring resonances happen to nearly overlap, there's the potential for instability.
---
Although resonance stability is a complicated issue, it sometimes becomes a question of comparing neighboring resonances. Say we have a planet -- we can start with the gas giant -- creating mean motion resonances, i.e. resonances arising from ratios of its orbital period to the orbital period of a small test mass, like an asteroid. You can define the "width" of a resonance, which describes the amplitude of oscillations around it. If the combined halfwidths of neighboring first-order resonances$^{\dagger}$ is comparable to their separation, then the resonances become unstable: the asteroid can oscillate from one to the other and experience chaotic motion, which in many (though not all) cases can lead to ejection from the system.
Quantitatively, some treatments say that test particles will experience chaotic motion if a quantity called the overlap ratio, $\gamma$, becomes at least $2/3$ (see section 3.3. of [these notes](https://www.lpl.arizona.edu/%7Erenu/malhotra_preprints/unesco_malhotra_rev2.pdf)); this is related to the better-known [Chirikov criterion](http://www.scholarpedia.org/article/Chirikov_criterion). $\gamma$ is defined as the ratio of the sum of the halfwidths to the distance between the resonances:
$$\gamma\equiv\frac{\Delta n}{\delta n},\quad\delta n\equiv\left(\frac{p+1}{p+2}-\frac{p}{p+1}\right)n\_p,\quad\Delta n\approx3.73p^{1/3}\mu^{2/3}n\_p$$
where $\mu\equiv m\_p/m\*$ is the ratio of the mass of the planet responsible for the resonance to the mass of the star, and $n\_p$ is the planet's mean motion.
Since $\delta n\approx p^{-2}n\_p$ for large $p$, this essentially reduces to the criterion
$p^{-1}\lesssim 2.1\mu^{2/7}$ for large $p$ (otherwise, use the exact expression for $\delta n$). You can also phrase this in terms of the planet's semimajor axis $a\_p$ and the asteroid's semimajor axis $a$:
$$\left|\frac{a-a\_p}{a\_p}\right|\lesssim1.4\mu^{2/7}$$
You're likely also interested in resonances arising from the presence of two bodies -- the gas giant *and* the super-Earth. This means we've now gone from the restricted three-body problem (the star, the gas giant and the asteroid) to a four-body problem (those three as well as the super-Earth) and is harder to deal with analytically. You might, though, be able to find related definitions of resonance widths and separations, and again consider the question of resonance overlap. I unfortunately don't know enough to say anything specific!
You could also attempt to simply run numerical simulations and see what happens. [REBOUND](https://rebound.readthedocs.io/en/latest/index.html) is an $N$-body simulation code I know some folks here have used; I haven't tried it out personally, but it's pretty well-documented and is easier than writing something from scratch yourself (unless you already have this sort of code lying around. . .).
---
$^{\dagger}$This means a pair of resonances like $p:p+1$ and $p+1:p+2$. An example would be the $1:2$ and $2:3$ resonances, where $p=1$.
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[Question]
[
Could fish (such as a moray eel) evolve chromatophores as advanced as a cephalopod's? Also how long would this take? I'm working on a speculative evolution project where moray eels are the only marine vertebrates. Some moray eels have evolved chromatophores to blend into their surroundings and 'hypnotize' crustaceans. Would the void of niches make this process any faster?
[Answer]
Evolution doesn't work on given recipes, so there is no predefined time it will take to evolve or re-evolve a character:
* a random mutation or set of mutations needs to happen,
* the organism bearing it has to get an advantage from it to be favored in the competition for life, or at least not be at a clear disadvantage
* it must reproduce to carry on the mutation.
So, if by chance a mutate moray eel should be born today with chromatophores but then it would end up being fished by a human or eaten by a predator before having offspring, that mutation would be lost like tears in the rain.
Also related to the randomness of mutation, anything can happen, given enough time. Of course certain changes are more radical than others and would require more changes to not hamper the life chances of their bearer.
[Answer]
The [genetic evidence](https://www.reed.edu/biology/courses/BIO342/2011_syllabus/2011_websites/ALPYSF/phylogeny2.html#:%7E:text=Evolution%20of%20Chromatophores&text=In%20most%20species%2C%20chromatophores%20are,is%20extremely%20rapid%20%5B5%5D.) tells us that cephalopods evolved chromataphors somewhere in the Cambrian era, so it likely wouldn't take more than fifty million years for a creature to develop them.
*Clarification*: I'm not saying that you could expect an eel to develop chromatophors in any 50 million year period. That's like predicting how a hundred rolls of dice would fall. I'm saying that, should eels develop chromatophors, this is the time period over which you could expect it to develop.
Environmental niches exist, even if ecological ones don't. An unopposed species could readily populate an entire ocean over fifty million years, diversifying into literally billions of new species. They would become their own competition, and probably their own predators. A world where only one Chordate species exists is inherently unsustainable over those time periods.
I can't tell you what the lower bound of that is, since I don't know how many mutations it would take to produce the ability you're looking for. The more sophisticated the color control you desire, the longer it'll take to get there. If you want octopus level blending, it might take the full five hundred million years.
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Is knuckle-walking efficent on snow / ice / thick snow ?
Can a predator large as a polar bear evolve this? Is protecting the claw in such way, to far fetch considering the fact that the beast need to travel long distance in the snow covered tundra and ice sheeet in order to track its food?
[Answer]
It doesn't seem a good idea.
Knuckle-walking concentrates the weight of the animal on the rather limited areas of the knuckles, meaning that both on snow or ice this will give problems: to avoid sinking in snow you want to spread your weight on a large area so that the snow doesn't collapse too much (principle on which snowshoes are based), while on ice the smaller the area the less grip you have, and knuckles do not even allow using claws/nails for additional grip.
[Answer]
The only animals that do knuckle walk have relatively delicate, and specialized hands that interfere with normal walking. You have Apes with dexterous fingers that can't easily stand upright for long distances and anteaters with specialized digging claws that are too long an cumbersome to be moved out of the way to put weight on the sole of the foot.
Claws are pretty durable. They're designed to tear apart trees, dig through soil, and rip through flesh. Bear claws don't need protection, but lots of things need protection from bear claws.
Keep in mind that polar bears have evolved to travel hundreds of miles in search of food, across snow covered tundra and ice sheets. Knuckle walking seems like an added complication for no benefit.
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The magic system is known as **shamanism**, and is centered around entering trance states to communicate with spirits and make pacts with them. My world is an animist setting, so things like humans, animals, plants, stones, rivers, and even human dwellings are considered "alive/animate". The ability to practice shamanism is not limited to humans (or Neanderthals for that matter); highly intelligent social mammals such as mammoths, wolves, cave lions, and whales are also capable of using magic.
When a shaman makes a pact, the spirit will always demand some kind of tribute in return for its help. Tribute can be a material offering, an immaterial offering such as prayer, a task to be performed, or simply a favor to be requested later. If the shaman agrees to pay the tribute, the spirit will virtually always follow through with its promise. Breaking tribute always results in negative consequences: physical/mental illness, poor hunting, natural disasters, even stillbirths and miscarriages (if a vengeful spirit decides to possess a pregnant woman).
The actual things a shaman can do with their magic are:
* **Healing:** All illnesses and injuries are caused by damage to one or more of a person's three souls. By guiding a deformed soul back into proper alignment, restoring a stolen soul, or banishing a possessing spirit, the shaman can kick-start the natural healing process.
* **Reading omens:** Shamans can train to recognize hints left by spirits to signal important events that have already happened, are happening now, or may possibly happen in the future. A shaman can also seek out omens by performing divinatory rituals, such as throwing bones or reading entrails. As the future is not concrete, the shaman can only predict different "futures" that are most likely to happen.
* **Elementalism:** A shaman can "talk to" the spirit of something in nature to ask it to do something. An example would be asking the spirit of a frozen river to melt the ice, or asking the spirit of a mountain to cause an avalanche.
* **Animal shapeshifting:** To take on an animal's form, a shaman must rhythmically imitate its sounds and/or movements until trance is achieved. The animal's skin may be worn as a cloak to ease the transformation.
* **Ancestral evocation:** A shaman can lead the spirits of the dead into the physical world from the afterlife and ask for advice, insight, or for access to the spirit's memories. This is frequently used for community-wide recounting of oral history.
Shamanic power is not an innate, hereditary trait. Theoretically, anyone could become a shaman, if they are willing to endure a dangerous initiation ritual and then train for years to master their abilities.
So, with all these things in mind, how do you think this magic system would affect the technological development of a Stone Age world? \*By "technological development, I'm referring specifically to the development of urban centers. I have a few ideas myself, but I want to hear other people's perspectives too.
\*Edited for clarity and specificity, my apologies for ambiguous wording.
[Answer]
**Depends on the Price**
How much of technology gets replaced by magic will depend on the cost of the magic. For example why would we ever invent agriculture if we could just ask the spirits for bountiful hunting and gathering every year?
The reason is the price might be too high. If the cost is a single animal to be offered to the spirits then it's a no-brainer. In that case people never settle or form a civilisation.
If the cost is half of the first-born children born that year to be sacrificed then it is also a no-brainer. In that case civilization progresses as normal.
The point is you can decide for yourself how different you want magic to make the world, by modulating the cost of the spells.
[Answer]
**It depends, can spirits cause harm in other instances than broken pact ?**
Shamanism could change humanity's worldview rather drastically, but knowledge that everything is more or less alive and sentient doesn't mean humans would respect the nature more, yes it is more likely but not the only option.
It all comes down to what spirits perceive as harm and/or do they have self-preservation instinct ? For example, if mountains consider mining in them as a danger to their existence and can conjure avalanche or cave-in, then i don't think civilization would progress very far, but if they are fine with mining or just aren't able to perceive it as dangerous, then civilization would progress normally.
This applies to everything that progress is based upon, do rivers consider digging irrigation systems as harmful ? Yes ? Agriculture is crippled. Do animals have capacity to consider domestication as dangerous ? Yes ? The wild boar you just closed in a pen, prayed to a river to cripple your agriculture. So there's that.
If realty is a bit more lax then i can see humans creating big settlements, maybe even cities that have minimal effect on environment, if possible from wood, stones and eventually bricks, if not than maybe by weaving trees into shapes like some kind of elves. This method of creating "infrastructure" is possible but rather time-consuming. And rest of their needs can be fulfilled by shamanism, especially medical care and food. But this leads to increase in population and bigger need for resources and depending on if it can be met, further grow or stabilization.
If you want to precisely know how far will humans progress you need to come up with the extent that nature is willing to be modified to. Also cost of pacts, but it was mentioned in Daron's answer so i won't dwell on that. Hope i helped
[Answer]
**Shamans did and do all of those things!**
* Shamans as healers persist to this day in our world. The persistence of shamanistic healing is evidence that people perceive value in the ministrations of the shaman. This is super easy to find. Faith healing is a fine example.
* Shamans of all sorts read omens and tell fortunes and there remains a robust market for these sort of psychic services to this day.
* Shamans who dance for rain or conjure weather or invoke spirits for good harvests are also still alive and well.
* Shamans who clothe themselves in animal regalia and simulate the movements of animals are also alive and well. Dragon dancing is a descendant of this.
* Shamanic communication with the dead is going strong. Seances are this. Whoopi Goldberg in the movie Ghost was one of these. Ouija boards are this, if you have one, and you are a shaman.
Your shamanic powers are all the real powers shamans had and have. We wound up with the world we have. Maybe you will assert your shamans are better at it. Maybe we would wind up with a better world.
But don't assert that your shamans are real and our world's shamans are fake! Did you see the part where shamans persist to this day? No reason to piss them off.
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## It will slow down technological advancement.
The big difference between your proposed world and ours, is that there is evidence of animism. As a consequence, this will seriously slow down — if not halt — many or all advancements relying on physical processes, since most of these processes are likely highly traumatizing for all materials involved.
All forms of agriculture would be like contemporary intensive animal farming, mining could be likened to disembowelling, &c.
If pacts demand tribute, these activities will surely cause a lot of negative yield, of debt. How will communities balance the scales? Will this even be possible?
This will also dramatically change ethics, values, norms, and laws, since everything will be a living, conscious thing with specific rights.
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## Context
As I was working on some mechanical ideas (and practicing art), I wanted to see how to render time in creative ways. So I decided to make an horizontal watermill akin to a turbine, which has markers on the outside borders and one blade with an arrow pointing outwards to tell the time. Here's my sketch of it [here](https://www.flickr.com/photos/195087188@N03/51929826157/in/dateposted-public/)1, and I've redrawn a very, very basic blueprint you can reuse if you wish to :
[](https://i.stack.imgur.com/ZgmFa.jpg)
Imagine you layed a circular clock on a table. At its centers emerge regularly spaced beams, akin to a watermill's or turbine's and which reach the inner border of the circle (There's just a tiny space between). One of the blade has an arrow pointing outwards, which points some markers in a circle. It's the hour hand. An external pipe gives in water directly into the clock, and another releases it. When you send water, you move these blades, moving the hour hand and changing which time it is.
## Problems
As a keen eye like you will see from my sketch, there are most likely mistakes in the drawing. Let's take away dubious proportions and other technical art flaws - that's more drawing skills and focus issues :p -, and let's talk about wheel speed and fluid physics. Here are the two main thoughts I have :
First, my unsophisticated intuition tells me that we're far off regarding the amount of incoming water (~quite big faucet input) in regard to the clock's size. If we think the drawn structure is 2 or 3 m in diameter, the flow seems to be too high to have the speed where the beam is moving at 30°/hour (ie. make a full turn every 12h). Or... Perhaps I messed up what should be the beam's shapes and where the water should come from and the thing isn't moving at all, I don't know. I'm just that bad at whirl-pulling accurate water physics models.
Then, would this thing ever move without overflowing? I mean, contrary to other horizontal turbines I looked at, there's little to no space between the blades and the floor, which means that water cannot evacuate under the blades. The same can be said regarding the space between the blade and the inflow pipe, since when a blade passes by the pipe, the water cannot really use the cylinder's capacity to get rid of the water.
## So how can I make this an anatomic... Technologically correct watermill clock?
That is, what troubles are there in the current model - potentially including others which were not highlighted above -, and what can I do to make them more plausible, in regard to real-world physics and following the intentions below? Basically, I want this to be more physically accurate than what I did.
## Goals to reach
My watermill clock goal is to tell hours and half hours, rather than minutes or seconds. As such, I don't care much if there are "sudden" jumps in the watermill's movement, as long as you can predict that it's around 11:00 or 11:30. **However, the clock should be reliable enough over days : We shouldn't have to recalibrate it every 2 or 3 days.**
**On top of this, the relationship between time and the watermill should be as direct as possible**. That is, unless the concept is critically flawed, avoid the turbine to provide power to other mechanisms and gears, which in turn moves the hour hand like most waterclocks do.
Also, by order of importance :
1. **I'm mainly interested in horizontal watermills rather than vertical ones.** However, I can allow some light inclination to the structure if it's needed.
2. **I'd like to avoid drop-by-drop water input for this to work.** I envision the flow to be more like one of a public fountain, an open faucet or shower head, for instance. More is acceptable, but not compulsory :).
3. Tech up to today is available, though no electrical, oil or gaz component are allowed. **Also, the simpler you can make it, the better.**
4. **For the size, it's to be put in public space,** so more than 2m in diameter and less than 8m, roughly. The overall structure's height shall not be higher than 1-1.5m (in order for people to read).
Then, less important :
5. We'll presume the water input is constant and at the rate you want. I already have ideas to make the flow constant, so let's only focus on the watermill itself!
6. Material (wood, metal...) is of less importance to me. I'm more interested in mechanisms and the way they should be applied. Still, you can reach a word about it if you find it beneficial :).
7. If it is useful, The inflow and outflow pipes can be moved and rotated. The beams length and shape can change, too, though remember it's a clock and the time should be easily readable.
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*1 : Not directly visible here because I wish to keep some basic rights on this drawing. Please don't reuse without consent.*
[Answer]
## Let the beams float and provide a circular flow below it
I would let the beams (mill) **float freely** on the water as shown. Design drawing already comes near.
You have a round container that contains the beams, but some **central axis** is needed, to keep the floating beams from colliding to the wand of the cylinder while rotating. This axis should add very little friction, to let this work accurately.
I would add a **calibration slider at the inlet**, which would cause a slightly de-centered mount of the inlet, causing the water under the beams to get a small circular flow component, the floating mill will rotate along. When your water inlet can provide for accurate inflow, the slightly circular flow under the beams will cause the rotation you need.The speed of rotation will depend on the decentered mount of the inlet. When the inlet is at exactly 90 degrees, your beams wheel will not rotate. When it would be, say 87.6 degrees (or whatever), you'd get the 12 hours tempo you need.
[](https://i.stack.imgur.com/ILvC4.png)
Additional advice: make the cylinder **wand deeper**, or try a **transparent** **lid** covering the construct. As it is shown, a design 2-3 meters wide will be susceptible to winds blowing over it. Depending on the direction of the wind, the floating clock beams will deviate.
[Answer]
**Pinwheel**
[](https://i.stack.imgur.com/lDZXO.png)
Pinwheels turn when they are faced into the wind. Put a pinwheel-like device on the centre of the turbine and make the water enter from above the centre rather than the side. This will ensure a consistent turning rate.
The cool thing about the design is you can vary the depth to vary the rotation rate, since the deeper water provides more resistence. Fine tune the depth further by putting a wad of blue tack in the exit pipe to raise the water level slightly. Remove and further bluetack as required.
[Answer]
**VALVES PROVIDE PRESSURE**
The walls dividing the compartments have simple, hinged valves that let water through to the right (counter-clockwise), but not to the left (clockwise). Water moving to the right will necessarily push the compartment left (opposite equal forces), until a new compartment is exposed to to the entrance water beam. The water that flows to the right of the entrance compartment exits through a hole in the floor. There may or may not be other holes in the floor as the compartments move clockwise, gradually emptying the water, or it may all flow out as the compartment ultimately moves onto the hole to the right of the entrance beam. For additional pressure, the half-full compartment that moves to the left of the entrance will spout water into the new, empty compartment, until the water levels equalize (when this happens depends on how quickly water can flow through the valves).
[Answer]
Main issue with any water clock is that flow is not constant.
Use [Mariotte's bottle](https://en.wikipedia.org/wiki/Mariotte%27s_bottle) for closed loop system, and for open loop use canal that will lower water head to constant level due to excess water flowing over canal's walls.
[Answer]
That's not exactly it butI still think it's worth talking about it. You could inspire from [drum clepsydras](https://fr.wikipedia.org/wiki/Clepsydre_%C3%A0_tambour), in which water is enclosed in a drum which has compartments. The asymetry of the water makes the drum rotate, and as it rotates, the water flows through small holes in the compartments walls. A pair of strings is wound around the axis of the drum, allowing it to go down as it rotates/unwinds. The hours are written on the chassis and indicated by the position of the drum's axis.
[](https://i.stack.imgur.com/JEpWo.png)
So there is no water flow through it, nor is there any exchange of water with the outside, but mechanical force is still required to regularly rewind the drum on its strings when it is too low on its chassis. This rewinding could be powered by a watermill and activated/deactivated by valves at the lower & higher end of the chassis.
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(this is doublet of my previous question, so I did a little improvement on it)
-my exomoon is around size of venus, but a little bit smaller.
* is very windy, so windy in fact filter feeders thrives in it air.
* have a day and night cycle around 1 year long.
-however it have almost zero axial tilt
* the plant life obtained blue leaves
* very tectonicaly active, so much so the sea in this planet resemble a connected mega lakes.
[Answer]
Simple answer is "not very plausible," but in an infinite universe, the improbable becomes the inevitable.
For a moon to be that volcanically active, it would need to either be very young (<100M years), or regularly squished by tidal forces of other moons (like Io). Both of these would make it difficult for it to have a thick atmosphere, but would make for strong winds.
This is a moon, not a planet, so a 1 year day/night cycle suggests that it rotates that much compared to the star its planet orbits. If its body is wracked by tidal forces, then you can guarantee that it's tide-locked to its planet, so it would have to orbit the **planet** once per earth year. There are moons of Saturn with an orbital period that long, but they're all airless rocks, and absolutely NONE of them are close enough to other moons to cause tidal force heating.
Let's go outside the realm of probability and say that we once had a planet with thriving life that got destroyed, and a huge chunk of the planet's ocean spun off as an ice moon/asteroid/comet. The ice froze before all of the elemental bits of life could decay. A billion years later, it enters a new star system and hits this other moon, maybe only 2-4x its size. This melts much of the moon's crust and covers it with a thick layer of water vapor atmosphere, and provides panspermia style fertilization.
Let's further posit that the planet it revolves around is a few times larger than Jupiter, generating enough heat to keep this planet warm while life evolves. The impact could adjust the rotation and orbit of the moon so that it has counter-rotation: it's nearly stable pointed at the star, but orbits the planet once every 60 hours or so. Thus, the planet would rise and set every 60 hours, but the star would stay stable in the sky for a long time. This would also explain a lot of the tidal heating.
Blue leaves is the easy part. Just presume that this planet's equivalent to chlorophyl absorbs red and green instead of red and blue. Chemically speaking, there's nothing magical about that.
Overall, highly improbable, but only the panspermia part is more improbable than the hypothesized Theia/Earth impact a few hundred million years after Earth's birth.
[Answer]
One massive hurdle here is the year-long night cycle. Back in the year 536 AD, cultures around the world recorded what turned out to be the longest night in recorded history; around a year and a half, during which an estimated 80% of the population died, people resorted to cannabilism, and in general, this paradise of a world became a cold hell. It's impossible to know how many species of living organisms went extinct during that time period, though apparently everything we see today was able to survive.
The plants would have to be well-equipped to deal with both the extreme heat built up during the summer(day) and the extreme cold built up over the winter (night). The animals here on Earth are already equipped for that, as are many of the plants, but anywhere near the equator the plants are rather unable to survive the cold, and only a few species of tree and moss are able to survive the long nights of our northern and southern extremities. With the nightly plant die-off/dormancy, the animals will have a hard time foraging and likely will almost entirely have to be omnivores. Just some things to consider.
Your other questions are covered nicely by these other answers, so I'll leave them alone.
[Answer]
I find it hard to even start thinking about this scenario, as even some definitions are vague and stand in the way of modelling it.
But let me try to disassemble some of it and maybe it will answer your question.
First Venus sized exomoon. It surprised me, but at the moment there is not an universally accepted definition on moon - planet system and binary planet system. In fact by some definitions even Earth-Moon system is in fact binary planet system, but I digress. One that seems to be fairly popular and makes an intuitive sense is the definition by barycenter, I.E. if the barycenter in within the radius of the planet, the other object is a moon, if it is outside, it is a binary planet system. This means that for a Venus like planet you need a fairly big primary planet my napkin math points to some gas giants or similarly massive rock planets.
One thing that will cause most troubles I think, is your 2nd condition. IF we use the Sun for our solar system, AND we need to stay within Goldilocks zone, then for a year log day night cycle, we will need our planet moon combo to be essentially tidally locked with sun. And tidally locked Goldilocks planet is not a great place of life to evolve. Any thriving takes place at the twilight zone which moves around the planet around the year.
Good news is, that you will have plenty of wind, as the air at the sunlit side gets heated up and rises, which pull the cold air from the sunset side giving you ever-present low altitude extreme winds towards the point of the moon that experiences high noon and at the same time high altitude winds towards the cold side of the planet.
In general tidal locking takes place AFTER the molten core of the planet solidifies, so this might be a problem, but it is apparently not a rule, so there can be some plate tectonics.
As with sees, the tidal locking would make the ocean situation very stable, and depending on your crust shape, I don't see why you couldn't have mega lakes. They would however be shifting quite a lot depending on whether they are facing the sun and evaporating rapidly or point away from sun and are frozen solid.
As for blue colored plant live, I honestly don't know hot to even guess. I would assume some fast growing weed/moss just might grow fast enough to stay within the twilight zone and keep shifting around the year, but ... this it too theoretical even for me
TLDR: Venus like exomoon- Plausible, windy- very plausible, year day night cycle - plausible, blue plant life - no idea, tectonic activity - plausible, giant lake-like oceans - no idea.
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I don't mean "biome" in the strict scientific definition, but rather, in the broader geological sense that it is used by game designers to refer to unique environments. On earth, when people go diving into caves, or even mining down into sealed caverns, they can find caves that have their own themes. Like caves with giant crystals, or caves with stalactites or caves with ominous murky white pools.
However, the thing about earth is that it has flowing water and even life to help create these environments. Can large asteroids have liquid water or magma sealed within it to aid in the process of creating awesome environments? Do they have geological activity? Or for that matter, is life possible inside of asteroids?
What kind of biomes could plausibly exist inside of asteroids?
[Answer]
Liquid substances inside asteroids are possible, because the outer shell of solid matter act as an insulator against the vacuum and cold of space. However, no matter how good such an insulation is, it won't last long enough to allow heart-like life to evolve.
It might be possible, at least in a purely speculative way, that the energy needed to sustain a biome can be supplied by radioactive decay, and that some sort of life emerges which can use radioactivity in the same way our photosynthetic organisms use sunlight, and on top of that build a food chain.
However I am pretty sure you can forget of awesome environments: black smokers at the bottom of our oceans are probably the most developed, non sun-dependent biomes on our planet, and are pretty dull when compared to anything shun by sunlight.
[Answer]
Q: *"What kind of biomes could plausibly exist inside of asteroids?"*
**Simple life, microbial mats**
Suppose your asteroid has some heat and a water layer, as explained by L.Dutch. There will be no life in the water layer, at first. When Earth life formed, life needed a surface to develop on, sometimes anorganic molds like pyrite. As there is no surface or gravity inside an asteroid, biomass will need some way to attach along the "coast" (wand) of the asteroid's internal ocean. Viable life inside an asteroid could be e.g. a unicellular species and another very simple multicellular, fungae-like species, which thrives upon the remains. The [microbial mats](https://en.wikipedia.org/wiki/Microbial_mat) formed by the unicellular species preserve the biomass and provide food for higher lifeforms. The fungae-like species will provide a cohesive substance that makes the mats stick to the rock. Both life forms should be able to maintain their metabolism without oxygen. There should be certain substances available to allow the organisms to build, e.g. carbon, silicate or metal crystal "molds" to support and shape primitive life.
I actually doubt if the available time will be sufficient to let a more complicated evolution take place. Even if there would be a heat source, it won't be there eternally. Because of the small size of the asteroid, there will be no room for native "macro-animals" or complicated plant life to develop, simply because there is no room for multiple, diverse populations. The emerging of macro (animal) life will not happen imho, you'll see only few, primitive species.
**Agriculture**
There are always engineering solutions. Animal life could be *planted* or *injected* into an asteroid and thrive in a controlled way. When the available food and/or energy is exhausted, new food can be injected, or life would need to be harvested in time.
**Asteroid life originating from a destroyed planet won't last for long**
Life could be a surviving subset of some existing evolution elsewhere. The asteroid was chipped off a larger celestial body that had abundant underground life. But in this case we're talking a really apocalyptic scenario ! There are no gentle collisions chipping off asteroids from planets. A planetary body can't fall apart, because gravity keeps it together. On a collision, planetary life will suffer mass extinction. Life must be very lucky - and living deep - to survive. But in this case, life is isolated from its context and resources: it could survive for a few thousand years.. no more..
**Immigrant life**
If life itself can be chipped off a planet and launched into space, it will depend on its resilience what happens. My favorite high-resiliance space travelling animals are [Tardigrades](https://en.wikipedia.org/wiki/Tardigrade), they look cute
[](https://i.stack.imgur.com/nU13z.png)
Tardigrade
.. but they'd need an entry, when the ocean resides underground !
[Answer]
**Cadbury comet.**
[](https://i.stack.imgur.com/p3MsXm.jpg)
<https://www.realclearscience.com/blog/2016/04/could_comets_contain_life.html>
>
> According to recent research published to the journal Astrobiology,
> large comets with a radius of over 10 kilometers could contain liquid
> water at their cores. The decay of radioactive isotopes of aluminum or
> iron could supply the heat necessary to melt the inner ice. Katharina
> Bosiek, along with her colleagues Michael Hausmann and Georg
> Hildenbrand, suggest that a thick layer of dust could protect the
> core's liquid environment from solar radiation...
>
>
>
Your mini-biome is a comet, loaded with water and biomolecules. Tholins from the void accumulate on its surface. When in the outer reaches of the system, warmth would come from radionuclides could be produced by heavy elements and also more transient isotopes produced by [cosmic ray spallation](https://en.wikipedia.org/wiki/Cosmic_ray_spallation). When the deep freeze comes, everything hibernates.
[Answer]
From what I understand of the current thinking, the problems are mostly geological (planetological). If an asteroid formed as a tiny planet (which is the current assumption for the asteroids we can see from Earth), then it was never big enough to have a molten core, or for light elements to accumulate on its surface.
So there are no processes to concentrate different elements in different places; the rock is just a uniform mixture of all elements, and light elements are either bound up in minerals or evaporated long ago. You can’t get caves because there’s no flowing water or limestone (formed from dead sea creatures), and you can’t get lava tubes because there’s no molten rock.
As a minimum requirement, then, your asteroid would have to be formed from the destruction of a mature larger planet (preferably one that had life). That being the case, you could certainly have sealed caves or even buried shopping malls if you wanted. Life might persist for a while, but after millions of years it would be far too cold, unless your asteroid happens to include a natural nuclear reactor (which is not impossible).
But generally, for life to *evolve* on an asteroid would be a stretch. Evolution requires change, and asteroids are fundamentally inert.
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Long story short, I have a bunch of folks with [Neolithic](https://en.wikipedia.org/wiki/Neolithic) technology, and they want to build a big ship - preferably, a ship that's as large as they can make it.
How big can these Neolithic folks make this ship? Assume that the amount of available labor and the will to build this thing are all non-concerns, and that this vessel is being built over many generations (let's say five), much like some European cathedrals. Resources are also a non-problem too, although they're limited to what can be produced and handled with Neolithic technology - no steel, aerospace composites, or electronics here, nosiree.
[There's certainly](https://en.wikipedia.org/wiki/Polynesian_navigation) precedent [for ships being built](https://en.wikipedia.org/wiki/Kon-Tiki_expedition) with Neolithic technology, so, at least in that regard, this question is based on an entirely plausible concept. I'm just asking how large such a vessel could conceivably get.
Also, I'm asking about one big vessel, not many smaller vessels, for multiple reasons that are irrelevant to the scope of this question. It has to be one big one.
[Answer]
* Like many such questions, you have to decide how far you can [uplift](https://tvtropes.org/pmwiki/pmwiki.php/Main/TechnologyUplift) your neolithic people before they are no longer neolithic. I believe both [clinker and carvel](https://en.wikipedia.org/wiki/Carvel_(boat_building)) boats are *bronze age* technology even if they are woodworking. So you would have neither without leaving the neolithic. Dugouts are limited by the availability of large trees, wicker boats are limited by stability.
* When you build a wooden ship, having many generations might not resolve anything. Once the logs are cut, they will start to dry and shrivel; once they are in the water, they will start to rot. So having a supply of [seasoned wood](https://en.wikipedia.org/wiki/Wood_drying#Drying_defects) when you start might be the way to go.
* Boats like the Kon-Tiki had a tendency to come apart during their voyage, which is kind-of-OK if you have an emergency radio and a plane ticket home. If you want a practical trans-oceanic vessel, it should be more likely to make it home than not.
So my gut feeling is a 100 to 200 cubic metres, possibly doubled in a catamaran arrangement. Certainly smaller than a [trireme](https://en.wikipedia.org/wiki/Trireme#Dimensions).
[Answer]
The linked Kon-Tiki was already more than a floating cork:
>
> The main body of the float was composed of nine balsa tree trunks up to 14 m (45 ft) long, 60 cm (2 ft) in diameter, lashed together with 30 mm (1+1⁄4 in) hemp ropes. Cross-pieces of balsa logs 5.5 m (18 ft) long and 30 cm (1 ft) in diameter were lashed across the logs at 91 cm (3 ft) intervals to give lateral support. Pine splashboards clad the bow, and lengths of pine 25 mm (1 in) thick and 60 cm (2 ft) wide were wedged between the balsa logs and used as centreboards.
>
>
> The main mast was made of lengths of mangrove wood lashed together to form an A-frame 8.8 m (29 ft) high. Behind the main-mast was a cabin of plaited bamboo 4.3 m (14 ft) long and 2.4 m (8 ft) wide was built about 1.2–1.5 m (4–5 ft) high, and roofed with banana leaf thatch. At the stern was a 5.8 m (19 ft) long steering oar of mangrove wood, with a blade of fir. The main sail was 4.6 by 5.5 m (15 by 18 ft) on a yard of bamboo stems lashed together. Photographs also show a top-sail above the main sail, and also a mizzen-sail, mounted at the stern.
>
>
> The raft was partially decked in split bamboo.The main spars were a laminate of wood and reeds and Heyerdahl tested more than twenty different composites before settling on one that proved an effective compromise between bulk and torsional rigidity. No metal was used in the construction.
>
>
>
Without technologies available to join together trunks and make longer assemblies, you are basically limited to the length of the tallest trees you can chop down, using a stone axe. Considering that you will use similar trees as beam, you are limited within a square.
20-30 meters is therefore what you can reasonably get.
[Answer]
This is a fairly complicated question, to which I believe a complete answer to be impossible. Anyway, here's my shot at it. First some questions:
1. Does it need to be a ship-shaped ship?
2. Where do your protagonists live?
3. What material and/or which animals do they have access to?
4. During the use, may there be one person dedicated to maintainance?
5. Does it have to be fit for the ocean? Or just near the shore?
If you don't need the ship to be boat-shaped, a multiple pontoon raft might be the better construction.
If your neoliths live in an area where large bamboo exists, this gives the better building material for the main parts, as it is very easy to split to flexible, tough, long strips. Otherwhise willow will work, but no where near as good.
If your neoliths have access to slightly larger animals (moose and simmilar), that would help with large skins, but again smaller animals (sheep) will work.
Assuming bamboo to be available the concept goes as follows:
**Preparation:**
You'll want to build roofs to keep at least some rain off your materials. You'll need something like 20-30m x 2-3m for your long material. Your baskets can be stacked and stored under 5x5m.
**Building-Blocks:**
* First large baskets are woven. Building baskets of about 2 m depth and 2-3 m width is easily a task Neolithic folks are capable of. These baskets don't need to be tight, but they need to be sturdy-ish.
* Then other baskets are woven. This time, an opening to the side is needed, large enough for a person to enter through. The first baskets will become pontoons, the second ones will help making the whole construction more sturdy. They will double as storage and crew quarters, if necessary. These second baskets are not *strictly* necessary, but they simplify things.
* Large strips are woven, (2-3) x (10-30) m. These may be used for the floor, as well as for walls.
* Many felts are prepared, turned to leather, and maybe even sewn in shape to wrap around the baskets. Similarly large sheets are created for roofing and for sails.
* Tar, resin, or bees wax is used to make the materials more resilient against pests and rot.
The baskets can be stacked top down and *small* fires may be lit under them to keep them dry and smoke them, keeping pests and rot away. (Keep in mind, that these fires should smolder at least 2-3 hours at least every second day, but it would be far better to keep the smoke going almost constantly...)
**Assembly:**
The pontoon baskets are wrapped in their leather lining and placed on the water. The strips for floors are placed on them and they are bound/woven into place. Larger "nests" of these are placed end-to-end as well as next to each other. Then their floors are interwoven. This is where the bamboo-strips shine, as you could get flexible strips of up to 30 m length, allowing for very solid links. These floors will not come apart (at least not easily).
(If willow is used instead, we have to rely on ropes instead.) Next the walls are added. By putting the second type of basket upside down on the floor, shifted by half a basket, and connecting it to the floor, the structure becomes a lot more sturdy. Also the outside is the perfect for attatching the connections between the walls to. This helps again with stability and allows us to close the shape.
This structure could easily be built to multiple hundred meters diameter. It could be round, long or pointy-ish, resulting in an over-all ship shape. Somewhere between 2 and 5 layers of living space are possible, even though more than 2 layers might not be sensible. If a few people go around and check if, and how much water seeped into the pontoons, and empty them by bucket, that should easily be functional for long times and small to medium-harsh oceanic use. For harsh ocean passage it is probably more sensible to build smaller ships and link them with ropes to a semi-fixed non-rigid patch.
If you can completely forgo any ship-shape, you can build a ***massive*** raft / multiple-pontoon-raft dwarfing our current oil freighters. After all, you got 5 generations and neither material nor workforce are of concern.
This will however only be semi-rigid, as it starts hitting the strength limits for your woods. Also it is probably stupid.
Which leads us to the final questions:
* What is the purpose of your ship and
* Why does it need to be *one* ship?
If the ship shape is a hard constrain, and you refer to it being a functional ship shape, about 40-50 m probably *is* the limit, with the 20-30 m that L.Dutch posted being the reasonable maximum.
] |
[Question]
[
In my story, Saturn’s moon Titan’s methane lakes are inhabited by microorganisms that photosynthesize, converting hydrogen into methane (A process thought possible on Titan after some study). This helps supply the methane continuously cycled through Titan’s atmosphere.
Enter my question. A horse-sized artificial life-form is set loose on Titan that is capable of “breathing” methane in the air (or drinking liquid methane and storing it) and producing hydrogen. Methane isn’t a substitute for oxygen, so the “breathing” process would probably be more similar to eating, but it would be nice if it still “looked” like breathing (for visual effect).
Is this feasible, and if so, how could this process occur? My first thought was combustion, but there’s nothing to combust with (Titan has little oxygen). Could it still be used alone to fuel a physically active animal? Most non-combustion processes I find for methane seem to involve oxygen and carbon dioxide anyway. Complex life without oxygen seems like a tall order, but if there’s an easy approach I’m open to it. Some other questions in this SE mention single-celled life, but I’m not sure if those solutions would apply to a much larger organism.
(If combustion is actually feasible, that would be ideal. Probably too extreme to be true, but I have a dream of the reaction making the creature exhale flames in oxygen-rich environments.)
[Answer]
You've got it backwards. Autotrophs (plant-equivalents) would not produce methane; they would consume methane (and probably nitrogen) and use the carbon to construct more complex organic molecules, releasing hydrogen as a byproduct.
Heterotrophs / animals would breathe in hydrogen, use it to reduce complex organic molecules, producing energy in the process, and breathe out methane (and possible nitrogen as well).
Hydrogen-breathing produces somewhere between a quarter and a third as much energy as aerobic respiration with oxygen, but hydrogenic photosynthesis is correspondingly easier (so there's more food available) and colder temperatures make metabolic processes potentially more efficient; plants can use a larger portion of the solar spectrum (so, again, more food than would be available in a terrestrial ecosystem with the same solar power input), and fermentation and reduction reactions have higher thermal efficiency, so animals don't actually have to eat 3-4 times as much after all. Even if they did, though, it is entirely plausible to have complex animals that merely have to consume 4 times as much food as their terrestrial equivalents; that rules out some of the less efficient types of creatures that have to eat nearly constantly just to survive on Earth, but plenty of creatures (including strict herbivores) eat relatively slowly, and could certainly handle a 3x increase in dietary needs.
[Answer]
The process of breaking methane into hydrogen to get energy is energetically possible: the [standard enthalpy of formation](https://en.wikipedia.org/wiki/Enthalpy_of_formation) for hydrogen is 0, while for methane is -74.9 kJ/mol
The problem is the upstream process that you call photosynthesis: the organism doing it would take hydrogen from the atmosphere, add carbon taken from somewhere else, add energy taken from the sun, and then throw everything away? It makes little sense. On Earth oxygen is released as byproduct of the conversion of water and CO2 into sugar. But in the way you depict it, the organism would do it for nothing in return.
] |
[Question]
[
I have an idea for a creature, and I want to figure out if it's possible. I'd rather not handwave it with "magic", so, here I am, asking the Stack.
The creature is eel-like, and is capable of emitting a chemical when scared that turns all water within a 5?( subject to change) into slime, rapidly (in around a few seconds). This traps predators, and it can escape by slipping through the slime.
Is this chemical possible? If so, can it be created through natural,biological processes? Also, can a slimy eel slip though the newly created high viscosity slime?
[Answer]
**You have invented the hagfish.**
[](https://i.stack.imgur.com/GgZ1x.jpg)
<https://www.livescience.com/57705-us-navy-synthetic-hagfish-slime.html>
Hagfish are elongated eel-like (as regards body type) fish that make lots of slime. I saw a video where one little hagfish turned all of the water in a bucket into slime.
<https://www.thoughtco.com/hagfish-slime-4164617>
>
> The Characteristics of Hagfish Slime When a hagfish feels threatened,
> it releases hagfish slime, a protein-based, jelly-like substance from
> slime pores that run the length of its body. The slime is a thick
> glycoprotein excretion called mucin, which is the primary substance in
> mucus, commonly referred to as snot or phlegm. Unlike other types of
> mucus, however, hagfish slime doesn’t dry out.
>
>
> The mucin is made up of long, thread-like fibers, similar to spider
> silk. These strands, which are arranged in bundles called skeins, are
> thinner than human hair, stronger than nylon, and extremely flexible.
> When the skeins come into contact with seawater, the glue holding them
> together dissolves, allowing the slime to expand rapidly. It is said
> that one hagfish can fill a five-gallon bucket with slime in only a
> few minutes. The slime fills the mouth and gills of the hagfish’s
> attacker, allowing the hagfish to escape.
>
>
>
The only problem with hagfish is that they are never used as school mascots. I implore the WB community to address this terrible oversight.
[Answer]
Your creature would have to release a massive amount of substances in the water.
A glue like substance soluble in water is the basis, e.g.
**Polyvinyl acetate**
<https://www.sciencedirect.com/topics/chemical-engineering/polyvinyl-acetate>
Then, in order to maintain the soft viscosity and reduce stickyness, add
* **Salt** or
* **Borax**
<https://littlebinsforlittlehands.com/basic-slime-science-homemade-slime-for-kids/>
<https://www.independent.co.uk/life-style/slime-toys-poisonous-chemicals-boron-parents-warning-which-a8450666.html>
How your creature would produce (or gather?) these substances, I don't know. But I think the amount of "excretion" needed will certainly limit the amount of water affected. The slime emitted would become a mantle around the creature, rather than extend far into the surrounding water.
It won't extend far. In order to affect all water around it, your beast would have to turn a relevant part of its own volume into slime. Slime consists of 90% water, so there would be at least 10% of substance weight that would have to be released into the water.
*Note:* in Earth's nature, some animals release defensive substances into the water. Octopus can do that, blinding the attacker.
<https://en.wikipedia.org/wiki/Cephalopod_ink>
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[Question]
[
I'm in the process of creating flying animals big enough to carry a human being on their back, the problem is that if it's too big, the wingspan also has to be and muscle will be needed for the wings to function properly, but muscles add weight and a lot of weight can anchor the animal to the ground. So I've been thinking about bones being made of metal, there are metals (like iron) in animals, so the animal's organism could gather enough metal to gradually add metal to the bones (it would be like a hybrid skeleton, 80-90% normal and 20 -10% metal) as the animal grows. But metal is heavy and I don't know if this "metallurgy" is possible, so I'm looking for something more plausible. **How to make the bones of a large flying animal hollow and at the same time strong?**
Data about the animals I want to raise for my world:
Pegasus: 21m wingspan, 1.8m high. Weighs 400kg.
Dragon: 18m wingspan, 3.60m tall. 300kg (because it has 4 limbs, so it weighs less than a pegasus that has 6).
Bird: 15m wingspan, 2.8m tall. 230kg.
[Answer]
Our bones are already 'hollow and at the same time strong'. Our bones have been the result of millions of years of evolution, each successive iteration slowly reducing the resources (mass) of bone structure needed incorporating a cellular structure.
[](https://i.stack.imgur.com/OcUS3.gif)
For birds and other flying creatures, such as bats, more so. Their entire being is 'mostly' to reduce weight - their bones being very hollow and strong, but also incorporating Air Pockets as above.
For larger, heavier animals this would continue. Keep in mind the largest existant flying animal, the Quetzalcoatlus, had a wingspan of 13.7m, and weighed 200kg. Although this is still short of your targets, it is much bigger than anything flying now. Your proposed wingspans do not seem too short of what may be needed - regardless though your weight of heavy animals may not benefit all that much from bones of metal after evolution's refinement of bone structure.
What may be more concern is your pegasus and how it can get off the ground. As this model shows, almost all of the creature's design and resources go into its size and wings. It was proposed that Quetzalcoatlus lived on cliffs, because if they landed on the ground it would be almost impossible to get the 'run up' they needed to fly:
[](https://i.stack.imgur.com/ikBb5.jpg)
] |
[Question]
[
I saw some questions asking about digitigrades and bipeds, but I could not find much when it came to swimming. I know the two are capable of swimming, but I was wondering **whether digitigrades or bipeds would be more efficient at swimming**.
I would think maybe plantigrade would be better because the legs do not have a bend and can move up and down like a flipper. A digitigrade could still swim, but it is more like how a quadruped would swim in which it is limited to a dog paddling style. However, that is not adding in a tail and fins. If it had fins along the body and a shark like tail, I would think the digitigrade structure would not be as much of a hinderance because the tail and fins help to counter the disadvantage. The opposite is also a factor. If it was a plantigrade with a tail of a dolphin and fins, I would think the outcome would be better because the legs work in a vertical motion along with the tail plus support from the fins.
Just for clarification, I am referring to human leg anatomy against anthropomorphic leg anatomy. Digitigrade is referring more to walking on the toes and not touching the ground with its heels while plantigrade means walking on the soles of the feet. Was unsure if those are the right terms to use but hopefully that helps.
[Answer]
>
> I was wondering which type would be more efficient at it
>
>
>
Efficiency in swimming comes from adaptations to swimming. If you're not adapted to the sea, you're not going to be great moving about in it. Get you some swimming fins, or a nice tail.
Humans can swim OK, but imagine if we had skinny plantigrade legs with claws on the end, in a vaguely birdlike fashion. Those kind of legs are obviously pretty poor for swimming with, independently of the walking style. Give those feet some nice webbing like a seagull, though, and you're back in business.
>
> If it was a plantigrade with a tail of a dolphin and fins, I would think the outcome would be better because the legs work in a vertical motion along with the tail plus support from the fins.
>
>
>
If you've got a nice tail suitable for propulsion under water, you want to be keeping your limbs tucked in to minimise drag. Have a look at how crocs swim, for example... when moving around slowly, they'll use their legs a bit, but when moving at speed the libs get tucked in and that big tail provides all the power.
>
> which is better for swimming?
>
>
>
Without adaptation, I don't think either is much better for swimming.
*With* adaptations though, there do seem to be a larger number of plantigrades, even evolving from quite different starting points... consider penguins and polar bears, for example. Clearly there's *something* driving that difference.
[Answer]
## Intrinsically, it does not matter
Digitigrade vs plantigrade only describes if an animal prefers to focus its weight on its tarsals or phalanges. But there is no hard rule in nature saying anything about how that affects your ability to swim. Without knowing what exact two animals you are comparing, there is no way to say for sure.
While most amphibious animals get called plantigrade, this is not really a good classification system to use for them since, it is more accurate to say that things like seals and turtles prefer not to walk at all, and what they do for land based locomotion is neither plantigrade nor digitigrade stride since they typically make ground contact with everything elbow/knee down, not just the foot; so, lets throw them out of the pile and look at actual digitigrade vs plantigrade.
There are many plantigrade animals like porcupines and chimpanzees which are terrible swimmers, and some like brown bears are great swimmers. Then there are some digitigrade animals that are poor swimmers like most breeds of domestic cats and dogs, and then there are those which are great swimmers such as tigers and horses. More over, even within a single species, there can be HUGE variances in swimming abilities. After all, some humans would drown if you threw them into a swimming pool while others can cross the English Channel despite having very similar walking preferences.
And sometimes... we just break the digitigrade / plantigrade rule all together:
[](https://i.stack.imgur.com/NPZqn.png)
[Answer]
## Plantigrade
Aquatic animals tend to have shorter, wider limbs. This clearly points towards human legs over digitigrade legs
Examples of this tendency can be seen in pinnipeds
[Answer]
# It depends. What role do the legs play?
Nature is filled with all sorts of different animals which have varied forms despite all coming from the same ancestor. The beauty of this is that even though we can find very different creatures, thanks to convergent evolution we can also find different creatures that look very much alike thanks to being exposed to a similar environment and evolving a similar bodyplan as a "solution" (yes, I am speaking as if evolution was a magical process where everything is premeditated even though it is clearly not). So basically, before looking at the limbs themselves, let's look at what nature selected as the ideal traits for a good swimmer:
* mostly streamlined, ideally torpedo-like shape.
* the ability to float.
* some method for forward propulsion.
* some method for changing direction.
These basically cover the most important things from a purely mechanical perspective (ignoring things like the ability to breathe underwater or hold your breath for long periods), and that's where leg shape becomes important or not:
Penguins, being part of the bird family, are naturally digitigrade, this however doesn't keep them from being good swimmers, because they made full use of their avian ancestry to turn their wings into paddles which they use to swim through the water, keeping most of their legs essentially inside their bodies, their digitigrage leg anatomy being more important for allowing them to move on land than they are at swimming.
Seals and sea lions took a different approach, descending from plantingrade bears if I'm not mistaken, they completely converted their hands and feet into flippers, with the main differences between the two being that the seal bodyplan is slightly more adapted for an aquatic environment than the sea lion bodyplan, allowing them to normally reach higher speeds at the cost of loosing most of their mobility on land (they can basically only move around by bouncing, meaning they're screwed if they're on land being pursued by something and water is too far away) while sea lions, while very capable of swimming at great speeds in short bursts, are overall a little less adapted for aquatic live, retaining their ability to turn their legs around and actually walk on land, as well as some other "minor" traits that differentiate both bodyplans. In this case the plantigrade posture was very useful, because the entirety of the feet could be converted into a flipper, rather than just the toes.
Dolphins and whales showed yet another design, which is also shared by fish: the absolute majority of the propelling is done via their tail, and unlike sea lions and seals, they had no plans on going back to land ever again. In such a scenario, neither plantigrade nor digitigrade is ideal, because the best course of action to get a torpedo shape if you don't need your hind limbs is to loose them altogether.
Whale evolution also shows us that at least for mammals plantingrade might be best, since while pakicetus (with little to no aquatic adaptations) was digitigrade (with traits common to hooved animals at that), ambulocetus (the mammalian attempt on making a crocodilian) had a more plantigrade bodyplan, with more evident adaptation to a semiaquatic lifestyle.
Crocodilians are the last best example I can thing of: they still needed their limbs due to not giving up on land, but don't often use them when actively swimming at high speeds, meaning their limbs are kept small, but strong in Order to do their job. Crocodilians, like many reptiles, are plantigrade.
What you have to keep in mind is: while digitigrade limbs are normally more associated with animals that need to reach higher speeds on land, plantigrade limbs normally mean slower movement speed, but more stability due to a greater surface area, which is also one of the traits you want to see in a fin used for swimming. If you're still going to go on land but your hind limbs aren't doing any swimming (be it because you mostly use only your forelimbs or a tail), either digitigrade or plantigrade is fine, so long as you have ways to either keep them small or within your body to be more streamlined. However, if you only need to swim with a tail and those hind limbs won't ever do any walking, ditching them is probably a better approach so they don't increase your drag in the water.
] |
[Question]
[
Snakemen are absolute beasts in combat when you factor in all of their snake qualities.
One of the ways they would be practically unstoppable is if they fought using constriction (credit goes to [Shadiversity](https://www.youtube.com/watch?v=2uVRKKdIYLI "What weapons would SNAKE PEOPLE really use?") for this idea). Or even just in general combat if they were to wield polearms and use their height advantage against humans. And if they fought this way they would angle forward and upwards to make the person they are fighting unable to get at them. Add that to the fact that snakes are able to use the full strength of their muscles for about 1/2 an hour at a time, meaning their bow shots would be more accurate, and they could hold up heavy polearms for an extended period of time, they would be very hard to beat.
But the thing is they have to wear full armor along the length of their snake body. Otherwise, they would be incredibly vulnerable in a battlefield setting where there are many opponents that would come at them from all sides. Or if they were to use their constriction ability, they would need protection so that they could get up close and personal without getting stabbed and hacked to bits.
And the type of armor it would have to be is chainmail with gambeson underneath. It would provide the most protection you could get (which is a good bit of protection.) and still have the flexibility needed for the snake person to move.
But there is a problem, wear and tear. Unlike humans, they have to move by slithering on their belly. And the armor has to cover their belly. So it will be repeatedly be exposed to mud, grime, water, etc, and get rusted and broken, therefore reducing its integrity and weakening it. And the chain links would rub up against the gambeson constantly. This would fray away at it and reduce its thickness and protection.
---
Is there a way to minimize/eliminate this problem? Perhaps with alternate types of armor that I missed? Or different materials? Or is this problem not as bad as I think it is?
**Edit:** This is snake people against humans. Not S vs S.
[Answer]
The problem is not wear and tear.
[Snake slithering is heavily dependent on the skin](https://en.m.wikipedia.org/wiki/Role_of_skin_in_locomotion#Snake). This means that wrapping the underside in armour wouldn't work, and that wear and tear would be a more minor issue. In light of this, normal considerations can be used for the armour of the back of the tail. They would need straps to hold it on, but wear can be avoided by the snakeman being careful to keep them off the ground. The specific armours to use would be gambeson, mail, brigandine, or anything else held together by flexible material. This is so that the entire tail armour can hold together, reducing the number of straps needed. The ideal armour would probably be a coat of plates with an outer layer of denim, leather, or some other strong material. The plates would be paired, and go from the mid-line to the edge of the belly. The paired plates should allow it to hinge open and closed, allowing it to be taken on and off. The plates would also have to be narrow and overlapping, to allow the snakeman to bend. There should also be a gambeson underneath, both to keep the plates off the skin, and to protect against any strikes that make it through the coat of plates. The armour would be attached using a tough belt near the human end, and a few straps. The straps could be held off the ground, but would still end up being scraped on the floor, and so the straps would need to be easily replaceable. This armour, despite its weak spot on the belly, should protect during constrictions, as snakes (or at least some of them) constrict with the sides of their body, which can be armoured.
[Answer]
1. **Snakeman armor is naval brass.**
[](https://i.stack.imgur.com/8qf1H.jpg)
[source](https://www.etsy.com/listing/205645297/snake-chain-2m-raw-brass-snake-chain-6mm?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=brass+snake+chain&ref=sr_gallery-1-42&organic_search_click=1&pro=1)
It is corrosion resistant and also super styling!
2. **Gambesons are made of rushes and plant material.** Whatever is handy, and which the snakemen stuff under the armor. If it is prickly that does not matter to them because their scales are hard. When the plants wear out, they stuff in more.
[Answer]
Multiple canvas layers would not be as effective as a metal armour, but they can provide some protection and can be produced quickly in bigger numbers. They have been used often in the past.
The most effective solution is a conventional armour with a canvas belly that can be replaced easily. Not single use, bot close to.
[Answer]
No. Their inability to wear gauntlets is legendary. Only partial armor is possible.
] |
[Question]
[
The underground city of Anwei is the last human refuge from the invasion of alien robot zombies. The enemies are very patient, and they are willing to besiege the city for decades if necessary. Luckily Anwei has its own food and water supply, and between local craftsmanship and scavenge from slain enemies, the city is more or less thriving, with the population of the city holding steady around twenty thousand for the last forty years.
New children are being born in this city constantly. They grow up, get some education, and eventually pick up some job around age 12; such as joining the defense force, farming the hydroponics, etc. Life expectancy is low, with many casualties even in ostensibly safe jobs due to hidden mines, toxic water, and so on. My question is about the mental health of these children: the second and third generation in this city.
Now some things that we might consider awfully harsh are just part of life for these people. In the middle ages, labour at twelve was not uncommon, neither was losing half your siblings to disease. These kids will just lose their companions to mines instead of dysentery.
But I do wish to be respectful to the mental side of things, and for that reason I hope there is a way to consider whether and when I am taking it "too far". I want my characters to grow up and be capable of laughter, affection, and having healthy relationships. Realistic trauma is something I wish to address when relevant, but it is not what I want my entire story to revolve around.
Basically I want my besieged city to be "safe" enough for children to grow up in and not suffer from emotional or psychological handicaps that would dramatically alter the way they behave from how we expect our protagonists to act. I ask, what circumstances and facilities must I provide for the city? Is it vital for example that bombshells cannot be heard from within one's bedroom? Must children not be allowed to see their wounded friends? What assumptions about "too harsh for children to experience" are western/industrialised bias and which are vital for people not to grow up entirely traumatised?
---
Consider mental health separately from one's morals or circumstances. If one of these people plays bowling with human skulls, but experiences the same joy as a modern westerner does when doing regular bowling, that is mentally normal behaviour in my book. The WHO definition of [mental health](https://en.wikipedia.org/wiki/Mental_health) is: "a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community".
[Answer]
**Introductory notes**
**1.** I favour an eclectic approach in psychology and I see these as the foundation of good mental health:
* no physical or genetic anomalies associated with mental problems (please note, physical defects on their own do not necessarily lead to poor mental health, however, they increase the risks);
* good enough mother: This concept refers to a caregiver (not necessarily a biological mother) who provides a child with adequate care and emotional support, particular styles of care and communication do not matter as long as the caregiver-child relationship is comfortable for both parties and is based on their needs (must not be [codependent](https://en.wikipedia.org/wiki/Codependency), though);
* adaptive coping mechanisms: This refers to behavioural and cognitive strategies that help to process negative emotions, adaptive coping leads to inner peace, i.e. low stress, sufficient self-esteem, etc.;
* meaningful relationships with other people: Humans are social beings and do best when they have positive emotional connections with other people, isolation from society is very harmful;
* balance between work and pleasure: People need rest, lack of rest and relaxation is detrimental for mental and physical health.
In addition to these, a life of stability (no sudden and dramatic changes) and structure can also be beneficial. I would also argue that well-defined social roles help the majority of people to stay mentally healthy and live happier (no angst of choice). However, overrigid structures and roles can be detrimental, especially for people who have rebellious or novelty-seeking personalities.
**2.** There are several different ways to define childhood. *My working definition is based on social roles: A child stops being a child when they assume adult social roles*. For this question, this means that children become adults at the age of 12. The period between 12 and early 20s will be called Young Adulthood. Adolescence will not exist in the described scenario.
**Part 1. Childhood (0-12)**
In our modern world children are often seen as pure, innocent, naive, and in need of a 'safe' environment. However, these are very new and novel concepts that did not exist before modernity. Throughout history, children were treated as small adults with their own set of well-defined social roles and responsibilities. One may even argue that the current obsession with safety and practices of sheltering children from everything (and resulting lack of agency and autonomy) have a much greater traumatising potential than previous historical attitudes.
For your setting, I would suggest going back to treating children as mini-adults:
* minimal sheltering;
* no hiding of ugly truths;
* early involvement in society as full members with defined and respected responsibilities (can be looking after younger children, housework, light public work, and alike).
This approach will minimise the shock related to the transition from childhood to adulthood. It will also help to develop and support decision autonomy and personal agency. Both are very important for mental health.
An additional benefit is the full (or almost full) disappearance of the adolescence crisis, which happens in our societies due to the clash of personal identities, responsibilities, available roles, and lack of agency. To put it simpler, adolescents rebel because they believe that they are already adults but they are still treated as children and are not allowed to decide on their own. This type of rebellion is very rare in poor families and regions where children take on adult roles early.
Your society can also adopt initiation rites. They will provide structure and clarity, facilitate coping with new social roles and requirements. Initiation may also work as a pre-emptive coping mechanism when it comes to war trauma: An initiation ritual may include the symbolic (or real) killing of an enemy which will prepare for actual battles. I would suggest looking into initiation rites in different societies and associated rituals.
Everything else is just common sense:
* limit corporal punishments of children (it is hard for me to say what is a good limit as I come from a culture where domestic corporal punishments are a norm [I never punished my children physically, but when I was a child, I and most people I knew at that time received such punishments]; I am also unaware of any research that would conclusively state that any type of corporal punishment is 100% traumatic for children; I do agree that heavy beatings should be strictly forbidden and punished);
* public schools (children need a place to learn and to socialise);
* basic siege training (may include basic military training, evacuation drills, basic medical training, etc.);
* playgrounds for younger children (unless your society is in dire need of workforce and children have absolutely no time for playing; please note, that even in the middle ages children had some free time to play);
* provide all basic necessities (food, water, and shelter);
* interest groups, clubs, etc. (these are very helpful for children to find like-minded individuals and to figure out what they are interested in, these groups can also become a place to look for and nurture talents).
**Part 2. Young Adulthood (12-25)**
Children become young adults when they assume adult social roles and responsibilities.
This part will focus on war.
For children and young adults born and raised during the siege, everything associated with it will be the norm: Bombing, poisonous gas, people dying, wounds, etc. None of these will be traumatising events as these are facts of everyday life. I also do not think that being underground will cause any psychological problems (except for the first generation that went underground).
Malnutrition and undernutrition may become a problem. Studies suggest that they lead to a wide variety of [negative effects](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6310421/) which [may persist](https://www.hindawi.com/journals/isrn/2014/453460/) [through generations](https://scholar.google.com/scholar?q=malnutrition%20generational%20effects) (the last link is to Google Scholar search; for those interested in exploring this in-depth). These are not psychological traumas or mental health problems per se, but this is something that should be considered.
As for psychological problems, I think that the most important will be:
1. inability to leave the city;
2. fatigue due to neverending war;
3. trauma associated with combat;
4. death of close friends and relatives.
Inability to leave the city is the least traumatic. The core of the problem lays within a lack of decision power. People have to stay inside the city whether they want it or not. I would expect the majority of people to cope with this on their own. However, there will be some adventurous individuals that will struggle. The easiest solution would be to employ them as scouts: Send them to spy on enemy's movement, look for resources, make maps, etc. Let them explore and enjoy freedom.
Mental and emotional fatigue and apathy when it comes to war will be the norm. It is not possible to maintain high morale and due diligence when war is going on for decades. This may even cause social friction between those who fought on the front lines and those who did not.
I would suggest a combination of propaganda with troop rotation. Change propagandist messages often, create stories of heroes, invite soldiers to schools and public gathering places. If an aggressive militarized culture works for you, it might be the best option. Every young adult will see participation in combat as their honour. Those who are traumatised by leaving their homes will be a rarity.
Troop rotation is very important for morale and diligence. Soldiers need rest away from a battlefield. They need at least some time where they can sleep, eat, and joke without any possibility of interruption. Make a rotation schedule and keep it.
Psychological trauma associated with combat will most likely manifest as PTSD, survivor's guilt, and depression. All of these need therapy1.
I checked research on PTSD to see if ages 12-25 are at higher risk of developing PTSD symptoms. Unfortunately, the results are inconclusive. One of the papers mentioned that PTSD in adolescents (15-21) can be related to identity issues that will be non-existent in your setting.
[The prevalence of PTSD among Iraq and Afghanistan military veterans is estimated to be between 13 and 20%](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5047000/) with some estimates going as high as 30%. The paper suggests that conventional combat is less likely to cause trauma.
In our world, psychotherapy in combination with medications results in [full remission for 30 to 50% of all PTSD cases and noticeable improvement in the majority of cases](https://journals.lww.com/jaapa/fulltext/2014/05000/posttraumatic_stress_disorder_in_combat_veterans.4.aspx).
In your world, psychotherapy is the only solution. Success rates will be lower. (There is also a possibility that in some cases PTSD symptoms can resolve after repeated exposure to traumatic events.) It does not mean that all veterans affected by PTSD will be permanently disabled and will become unproductive members of society. Not all cases are extreme and many symptoms are manageable. Your society also should be more tolerant and accepting of war veterans and their problems, which should alleviate the situation as well.
Depression and survivor's guilt are often chronic conditions. They can be managed with psychotherapy.
I would suggest psychological consulting after each deployment. Many traumas can be resolved if found early. Soldiers who show even minor symptoms of psychological trauma or distress should be placed into therapy. Access to alcohol (and drugs if any exist in your setting) should be limited since patients with PTSD and depressions often form substance-use disorders.
The death of close friends and family is always traumatic. However, I believe that in your setting people will be able to cope with it better since death is so common. Therapy should be needed only in exceptional cases. Funerals help the living to sort out their emotions and say their final goodbyes to the deceased. So, make sure your society has a funeral culture. Glorifying war sacrifice can also help as people will feel grief but also pride and honour of being related to war heroes. The Russian attitude toward the Great Patriotic War (1941-1945) can be of interest here and provide some insights.
All age groups should have access to recreation. If people are unable to relax, their survival will be compromised. No matter how desperate the struggle is people need time when they can forget about everyday matters. The type of recreation depends on your world's specifics. I would say that social activities where people interact with each other and form meaningful relationships are much healthier than many other options. Perhaps, you could do some public discussion events, dance parties, social parties, sports competitions, etc.
In addition, healthy drinking culture and relative freedom of sex should help. Drinking with friends may have a therapeutic effect if it allows opening one's heart, relaxation, and experiencing an emotional connection with other people. Drinking is also helpful when it comes to bonding: It is easier to make friends when everybody is slightly intoxicated. Healthy drinking culture may also decrease the prevalence of alcoholism. The specifics of such a drinking culture depend on your personal preferences.
The role of sex is rarely mentioned. However, sex does help with bonding and mental relaxation. Whether you want to establish brothels2 or not and how they work is entirely up to you. I would only warn against adopting negative attitudes toward sex and forbidding sex outside of marriage. Let young people enjoy themselves as much as they can while they are still alive. It will also help with birth rates :)
**Final thoughts**
Humans are very resilient as a species and can adapt to a wide variety of circumstances and environments. In a setting where war is always at your doorstep those who cannot cope will die very soon. It might be a cruel thought, but it is a good thing for your society as it will become stronger and fitter.
However, it will only work if people have hope and they see their lives as meaningful. Only under these conditions do people have the will to live. Survival is not the same as living a full life. It is not enough to survive. Without knowing why do you live, survival is meaningless. Without hope, life becomes a nightmare.
This answer is already extremely long, so I will not elaborate further. I would suggest reading about [existentialism](https://plato.stanford.edu/entries/existentialism/) to get some idea of how meaning can be approached.
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IMO, in your scenario, it would make sense to make raising children a collective responsibility. Considering high casualty rates, nuclear families (only parents and children) might not be possible. Extended families (several generations living together) may also be insufficient if grandparents do not live long enough. You might consider developing a public system that would supplement and replace when necessary parental care. Also, orphanages have a bad reputation but they might be a necessity in your setting.
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1 There are many different types of psychotherapy. What works for some people does not work for others. If possible, have therapists that practise different approaches. Also, support groups (without a therapist) and social workers can help with cases that need prolonged intervention and monitoring. A lot of people benefit simply from sharing their thoughts and experiences with people who can relate to them. Social workers help with social adaptation and mundane problems that someone affected by mental trauma can experience after returning from the front lines (this makes a person feel cared for, not isolated, not so lonely and non-understood, i.e good for mental health). Social workers will also be of invaluable help when it comes to orphans.
2 Prostitution is a highly politicised topic these days, so any research should be viewed very sceptically. Some studies claim that legal prostitution reduces the prevalence of STDs and rape. Other studies suggest the opposite. The morality of this issue is another widely discussed aspect.
It is my personal opinion that sex work can be performed safely and in a dignified manner if sex workers are given enough agency, coercion is strictly forbidden and heavily persecuted, and there is a well-thought-out and fully enforced labour code to protect the rights of sex workers. It is also important to have social attitudes that respect and do not denigrate sex workers.
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Emotional health seems to be about being able to accept what is happening. When I talk to people who went through trauma as children, the ones who are healthier are those who are able to talk about what happened, are accepted for their feelings at the time, and they live in a community that provides caring. Those that have worse outcomes are those who are told to forget it happened, told that they needed to "grow up" and not have those feelings, or told that it didn't happen or even are punished for talking about what happened. These can heal as adults if they are provided with a group that accepts them as they are and allows them to talk about their trauma.
So, emotional health is not about what trauma they go through, but how they are given the support to accept what happened and continue to live with the joy that children have with life.
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## You need to redefine emotionally healthy
Consider a person from the early United States - accustomed to brawls, ready to challenge to a duel if insulted. Is such a person emotionally healthy in the modern U.S.? Would a person from the modern United States be viewed as emotionally healthy in theirs? Look around the world - Afghanistan, North Korea, Russia, Rwanda - how many of those people are emotionally healthy as viewed from another country's perspective? (I think it depends primarily on whether you want to be diplomatic or undiplomatic in your assessment)
Emotional health is a collective phenomenon, and also a response to the environment. I imagine in your environment there would be few finer treats for kids than to take them out to the wall and give them a chance to snipe at the alien robots. A prize for the daily winner - a chance to compete for a military scholarship! *"Be careful to keep your head down!"*
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Before I offend everyone let me clarify that I mean no harm, I'm just ignorant. I never figured out what gender identity is since mostly only rainbow people talk about it and I always identified as myself and not as a gender. The first time I ever heard the concept of gender identity was back in 2017 and never managed to figure it out, too complex for my reptilian brain. I'm 23 and I only know about gender identity from YouTube, people in real life, at least in all the countries I lived so far (Italy, Greece, Romania and Hungary) they never mention things like gender identity.
So maybe the premise of this entire question is completely wrong due to my ignorance but googling around and doing some researching... I just get more confused than before.
So, in a world where males and females can do whatever the hell they want in society regardless of gender.
Gender is not a role but just a sex, gender means only what kind of junk you got in your pants not your role in society and how you are supposed to act, talk and think.
In this world people can identify each other easily from smell, you don't need to do anything to make your gender public, everyone will know just from smelling you at a distance.
So would people with gender identities still exist in such a world? Or would they instead develop a smell identity maybe even to the point of having transhodorous people masking their scent with perfumes?
Clarification:
As far as I understand it gender roles where adopted for different things but one of them is that even if the bone structures of men and women can differ, at the end they look really similar. Specifically when you have many populations of people without beards, teens, juvenile adults... And males with physical feminine features as well as females with masculine features.
What I'm referring too is more like a gender etiquette... Like boys cut their hair and girls wear skirts, side things society use so males who are not particularly masculine and females which don't look particularly feminine do not have to scream and announce their gender every time they meet someone new, everyone can guess everyone else's gender just by their mannerism and clothing.
Now, removing any gender role and gender ediquette, every time you see a woman who's not so curvy and looks like a feminine boy, you don't have to ask her gender, you just feel the scent.
Missgendering people can easily happen during mass gatherings where a lot of unknown people gather for festivities, rituals and political things.
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Yes, broadly. If for no other reason than it is necessary to know one's biological sex in order to reproduce and keep the species going. The dwarves in Terry Pratchett's *Discworld* series are a good example. While dwarves are a monomorphic species and men and women have identical gender roles (a major subplot is about younger dwarfs rebelling against their parents' norms and experimenting with human-style gender roles), it is still well-known that males and females are not the same thing and that this matters with regards to the one area in which the two sexes are not identical: the game of dating.
As Pratchett states, dwarf dating mostly consists of very tactfully asking the other what they have under their skirt. Because in the case of the dwarfs genitals *do* matter when it comes to sexual orientation (most organisms tend towards heterosexuality due to natural selection and hormonal stimuli, if a species mostly wasn't driven to pair up with members of the opposite biological sex [excluding hermaphrodites like sea slugs] they wouldn't reproduce enough to survive), and they need to pair up with a member of the opposite biological sex in order to make offspring. This despite the fact that the closest any dwarf has ever gotten to differences in gender roles is rebellious female dwarfs using rhinestone-encrusted axes and grooming her beard differently.
A quote from the author himself on the topic...
>
> “It wasn't that dwarfs weren't interested in sex. They saw the vital need for fresh dwarfs to leave their goods to and continue the mining work after they had gone. It was simply that they also saw no point in distinguishing between the sexes anywhere but in private. There was no such thing as a Dwarfish female pronoun or, once the children were on solids, any such thing as women's work.”
>
>
>
― Terry Pratchett, The Fifth Elephant
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One thing to realize is gender comes well before there's enough brain to waste it on things like "culture" or even "language".
In our biological world gender and gender roles are very common in almost all branches of the taxonomical tree.
The same holds true for individual deviation from the overall "mean behavior".
These "deviations" are much more frequent in "higher" branches, where we see a more widely used neural system and thus behavior is more and more determined by individual experiences and less "fixed" by "wired instincts".
Deviations too far from the "mean" tend to impair reproductive power and thus are "discouraged" by Natural Evolution; the more so in species threatened with extinction.
OTOH difference in specifics of gender roles are of infinite variety, also for species near the top (as we see it, insects would have different a view of the matter).
One quirk of "intelligent" species is they tend to culturally freeze some behaviors and thus equate "different" with "bad" (here is the seed of some of the problems with "gender", but not only, of course).
If you want to build a plausible world you need to keep into account the whole reproductive cycle, not just how different sexes recognize each other.
Fact we recognize women by certain sex attributes instead of scent is relatively unimportant; fact a mammal female takes a long time to make a child, she is "less fit" in that period, newborns are in need of parental care and similar factors have a much deeper impact and "culture" is shaped in a way that maximizes survival in a certain environment.
If you really want to build a culture with little or no "gender" differences you can have several possibilities:
* have hermaphrodites.
* invent some sex change mechanism (e.g.: born female, but switch sex on childbirth and then revert after some time).
* shorten drastically childbearing (to the limit: just lay eggs) and have both parents to take care of newborn.
* go the technological way: i.e.: have enough "social help" that there is no real difference between parents (to the limit: use "artificial womb" and "robotic nurseries" to cancel sex-specific tasks).
* have long lived race where childbirtt is extremely rare and thus, while an "event", it does not really impact everyday life.
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Like many things it really comes down to only the author can really say what makes sense for their world's cultures. However, gender identity, for some people, is about more than just gender role - It can also be about the *physical* aspects of gender/sex, which in the example you provided, could definitely include scent, as well as any other physical differences that might exist between the genders.
So yes, it can exist. Whether or not it does or should exist is really a question only you can answer - What makes the most sense to your image of this world and culture?
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I'm writing a fantasy novel with a race of intelligent and technologically advanced dragons. now, if we pretend that they can somehow fly, **How would they utilize boats and ships in order to traverse oceans?**
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As long as the ship buys them something of more value than traveling the same distance, flying, the dragons will have an advantage in using ships.
Some possibilities:
* Cargo. This one may simply be better than flight; the water provides the buoyancy, and the ship just has to move forward. A dragon would have to lift the cargo as well as fly it.
* Less work. Flight is calorie intensive. A ship gets its motion from air or an engine. Or even from being rowed; buoyancy means that dragon rowers just have to move the ship forward, not keep it in the air, which may easily counter-balance the weight of the ship. This means they need less food or can do more work.
* Time. Bask in the sun and contemplate great plans with the thoughts that would otherwise have to be expended keeping track of air currents and looking for downdrafts.
* Safety. A ship can be shipwrecked, of course, or blown off course, but this is aggravated in the air.
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So, from what I've read of [Porter & Grundy (2011)](https://iopscience.iop.org/article/10.1088/2041-8205/736/1/L14/pdf), most gas giant planets orbiting within their star's habitable zones are thought to have migrated there from further out in the solar system, with interaction with other planets or planetoids resulting in them stopping within the habitable zone without turning into "Hot Jupiters". In the process of migrating inwards it's possible for them to capture terrestrial planets, some of which will stabilize into circular orbits and become new large satellites (again, see Porter & Grundy).
My question is, what's likely to happen to a terrestrial planet as it's in the process of getting captured? For simplicity, let's assume that a Jupiter-sized planet migrates inwards and captures an Earth-sized planet, which eventually becomes a moon. **What would be the effects to the surface of this planet?** Would the tidal forces be extreme enough to cause planetary resurfacing, or just an acceleration in plate tectonics? Presumably there would be drastic climatic consequences, but assuming this planet had atmosphere and multicellular life at that point, would it remain "habitable" in any sense of the word?
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TL;DR: appearance of giant tides destroys coastal habitats, moons get lost, probable big volcanism events with associated climatic change.
Mass extinctions probably inevitable.
Tidal locking will eventually cause a hugely extended day-night cycle that will be ecologically apocalyptic. Eventual loss of geomagnetic dynamo seems likely to result in loss of atmosphere, leaving an ice world with deep ocean life only.
Look on the bright side though, my take may be pessimistic, but it is by no means guaranteed to be true. As I recommended on your last question, have a read of [this question](https://worldbuilding.stackexchange.com/q/163983/62341) and M A Golding's [links](https://worldbuilding.stackexchange.com/a/163999/62341) for ways in which an exomoon might be made habitable.
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Leaving aside the improbability of an inwards-migrating gas giant capturing a small inner planet (try running it in a gravity simulator; the most common result of any interaction is "flung off into deep space"... disappointing but true) lets think about the tidal issue.
Firstly, lets talk [Hill Spheres](https://en.wikipedia.org/wiki/Hill_sphere#True_region_of_stability), and limits to the new orbit of the capture world.
$$ r\_H \approx a\sqrt[3]{m \over 3M} $$
where $r\_H$ is the Hill radius, $m$ is the mass of the orbiting body, $M$ is the mass of the orbited body and $a$ is the radius of the orbit (I'm assuming everything is circular, for convenience). For Jupiter orbiting the Sun at 1AU, thia ends up being about 10 million kilometres. Stable orbits can only exist within half to a third of the Hill radius.
Lets assume your Earth was captured into a circular orbit at 5 million kilometres. Its own Hill radius is now reduced to a bit over half a million kilometres... this *is* enough to include the Moon, but the Moon is now outside of that critical half-to-third limit, and its long term future is now in jeopardy.
You could reasonably assume that over a long enough timescale (say, a billion years) that the Moon is *gone*.
Next lets talk about [tidal forces](https://en.wikipedia.org/wiki/Tidal_force).
These are Quite Complicated, but stripped of most of the complications you end up with something that looks a bit like $F\_T \propto {M \over d^3}$, or, the strength of the tidal force is proportional to the mass of the body generating the tides and inversely proportional to the cube of the separation of the affected body from the affecting body.
The Moon therefore generates a tidal force with a magnitude a bit like ~1.3x106kg/km3, whereas Jupiter will now generate something like 1.5x107kg/km3... that's a little over a tenfold increase.
Tides on your relocated world are gonna be **big**, make no mistake. Intertidal zones will become substantially larger, and this in turn will have all sorts of interesting effects on things that live in shallow water. Whole complex coastal ecosystems we see on our Earth, like [kelp forests](https://en.wikipedia.org/wiki/Kelp_forest) will cease to exist in the forms we're familiar with. [Mangrove forests](https://en.wikipedia.org/wiki/Mangrove) are another which will probably be washed away.
[Tidal heating](https://en.wikipedia.org/wiki/Tidal_heating) will also become *more* of an issue, but I can't tell to what extent, or over what timescale. Tidal effects are complicated, and tidal heating is best understood in objects with eccentric orbits which have already had their own rotation tidally locked (eg. Io). A full investigation of the problem probably warrants a good read and understanding of [Tidal dissipation in a homogeneous spherical body](https://arxiv.org/pdf/1406.2376.pdf), and I'm not about to do that for you today ;-) [Tidal Heating of Earth-like Exoplanets around M Stars: Thermal, Magnetic, and Orbital Evolutions](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4582693/) suggests that high rates of heating associated with eccentric orbits can drive runaway greenhouse effects, probably sterilising the biosphere. Given that it is already somewhat implausble that the Earth would be captured rather than ejected, to hope that it is captured into a nice circular orbit to avoid excessive tidal heating seems even less likely!
You can of course handwave this as you see fit; ultimately it isn't *impossible*, and as far as we can tell we already live on a planet which is a bit unusual and the galaxy is a big place.
Next, tidal locking.
The time for a body to become [tidally locked](https://en.wikipedia.org/wiki/Tidal_locking#Timescale) 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), $a$ new 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 Jupiter, $k\_2$ 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)
This ends up with a timescale of the order of 1.23x108 years... that's pretty fast!
Now, most of the angular momentum of the Earth-Moon system is in the Moon, but we've already established that the Moon is now in an unstable orbit and will in all likelihood be gone in under a billion years (possibly *well* under). Without the tidal influence of the Moon helping drag Earth back up to speed, it will probably be tidally locked to Jupiter in a timescale of the order of a billion years, too (which means "probably not as fast as 100 million years, but probably faster than 10 billion years).
The huuuge tides will slowly wind down, and the tidal heating will lessen. Now you're left with a "day" which is more like 72 old-days long. For the side facing Jupiter, the month-long night will have reflected light from Jupiter shining upon it... it will be cold, but not dark. For the outer-facing side the night will be very long and very cold indeed.
The big temperature differential between the day and night sides will drive strong winds... maybe continuous storms, maybe not, I'm not sure. Thick layers of ice and snow will form on the night side, blanketing everything.
Probably most complex surface life will be destroyed in this environment. Complex undersea life, such as that which formed around [black smokers](https://en.wikipedia.org/wiki/Hydrothermal_vent#Black_smokers_and_white_smokers) may never even notice the change in their situation.
At some point the geomagnetic dynamo will probably grind to a halt, too. The magnetic field will be vastly weakened, and the solar wind will slowly strip away the atmosphere, eventually leaving a frozen iceworld where life can only exist in the deepest oceans.
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The most notable change I can think of is a consequence of the very likely tidal locking which the Earth-like planet would incur once orbiting the gas giant: like our moon, it will develop a tidal bulge on the side facing the gas giant.
This would also mean that there would be no large tides on the planet, except for those induced by the star, but those would be minuscule with respect to the effect caused by the gas giant.
With less significant tides it might become also more difficult for life to leave the seas and venture on land, at least following the path which on Earth lead from fishes to reptiles and mammals.
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Can a planet have its whole surface covered with a 50% carbon dioxide and 50% water ocean (the substances being diluted in each other)?
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### Yes - with temperatures and pressures so extreme they blur the definition of "Ocean" *(and "liquid")*
So there's this crazy thing called "a [supercritical fluid](https://en.wikipedia.org/wiki/Supercritical_fluid)", which behaves as both a liquid and a gas when sufficient temperature and pressure has been reached. (So - it's *partially* an ocean - depending on how strict your definition of "liquid" is).
*Not too much of a stretch - it's in the "liquid" part of the triple point diagram*:
[](https://i.stack.imgur.com/9Q5Ku.png)
From the linked wikipedia page, carbon dioxide reaches it at 304K at 7.38 MPA. Water reaches it at 647K at 22.064MPA. So to get both supercritical, you're looking at a planet around 700K, 30MPA. Basically get venus and triple the pressure.
According [to wikipedia](https://en.wikipedia.org/wiki/Supercritical_fluid#Mixtures), any two supercritical fluids can generally be mixed together into a fully homogeneous solution. So long as you pick a point of temperature and pressure that's supercritical for both CO2 and H20, you can mix the two into a perfectly dissolved fluid.
At 700K, 30MPA, CO2 is [219mg/cc](http://www.energy.psu.edu/tools/CO2-EOS/index.php), water is about 320mg/cc. A approx 2:3 mix by volume will be a approx 50:50 mix by weight.
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This is the [solubility](https://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html) of $CO\_2$ in water
[](https://i.stack.imgur.com/1h6FC.png)
As you see, it is in g/kg. A 50% concentration doesn't look plausible. Moreover, in Earth like conditions $CO\_2$ goes directly from solid to gas.
To have it liquid you would need higher pressures, as seen in the $CO\_2$ [phase diagram](https://www.engineeringtoolbox.com/CO2-carbon-dioxide-properties-d_2017.html)
[](https://i.stack.imgur.com/ykxsM.jpg)
Based on this [paper](https://pubs.acs.org/doi/abs/10.1021/ie50408a015), in the range -29 C, +22 C and 15 to 60 atm, the solubility of $CO\_2$ in water goes from 0.02% to 0.10%. This can be expected, considering that $CO\_2$ is non polar while water is.
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I just did some research on the Chicxulub crater in the Yucatán Peninsula in Mexico, which is the crater from the asteroid responsible for the extinction of the dinosaurs.
Yucatán itself does have several noteworthy caves like Loltun Cave and the Calcehtok Caves, but their size pales in comparison to Mammoth Cave in the United States.
Does the shape of the asteroid affect the damage it causes to the planet's crust? If the meteor was oblong would it open up more of the crust?
[Answer]
From the wikipedia page on the [Chicxulub crater](https://en.wikipedia.org/wiki/Chicxulub_impact#Geology_and_morphology)
>
> Along the edge of the crater are clusters of cenotes or sinkholes,[43] which suggest that there was a water basin inside the feature during the Neogene period, after the impact. The groundwater of such a basin would have dissolved the limestone and created the caves and cenotes beneath the surface.
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Considering that the impact site is going to be messed up quite a bit by the impact itself, more than the shape of the impactor I think it is important to have the right composition of the ground: caves, cenotes included, form because water dissolves limestone. Considering that limestone deposits after the impact (whatever is there before will be morphed by the impact heat and pressure).
For the shape of the impactor, considering that the [Earth crust](https://en.wikipedia.org/wiki/Earth%27s_crust) ranges in thickness between 5-10 km for oceanic crust to 30-50 km for continental crust, I don't see that big difference, because once the crust is removed and the mantle exposed the consequences are pretty much the same (Chicxulub crater reached 30 km of depth).
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I am trying to develop an herbivore/rodent which, for the lack of better naming, I have temporarily named "sleepy skunk".
The main feature of this animal is that, whenever it feels threatened or is attacked, it freezes, sprays a mixture of gas and droplets and then assumes a "ball posture", wrapping around itself. The mixture is produced either in its intestine or in a gland evolved for that purpose, located around the perineum.
The mixture is active by both inhalation and mucosae contact, and its effect on the target is that it induces a drowsy state or even loss of consciousness, depending on the concentration. The sleepy skunk avoid its effects by being able to sustain apnea and immobility for several minutes, enough for letting the gas knocking out the attacker and then leave the scene.
Is there a realistic chemical path for an animal, or its intestinal flora, to be able to synthetize a chemical with such features?
[Answer]
Sounds like an opiate (or [opioid](https://en.wikipedia.org/wiki/Opioid)) of some kind might fulfill your requirements.
In the real world, fentanyl dust is quite a dangerous thing and police and paramedics who come into contact with it at the scene of an incident are at some risk: [Protecting First Responders from Fentanyl](https://www.safetyandhealthmagazine.com/articles/18290-protecting-first-responders-from-fentanyl-exposure-niosh-releases-video). Some kind of fentanyl was used in the [Moscow theatre hostage crisis](https://en.wikipedia.org/wiki/Moscow_theater_hostage_crisis). Note that opioid overdoses can cause death by respiratory depression!
Natural opiates obviously exist, and many kinds of opioids are synthesised internally in various colours and flavours of species for different purposes. Something quite as powerful as fentanyl might be a bit surprising, but not entirely impossible.
Note that if it were as dangerous as fentanyl and related chemicals are, it might be suitable for hunting with rather than merely defense.
Note also that an animal that farted heroin when stressed seems like something likely to be caught and farmed for recreational (and maybe even medicinal) purposes.
[Answer]
The skunk produces
# [Diethyl ether](https://en.wikipedia.org/wiki/Diethyl_ether)
>
> Diethyl ether, or simply ether, is an organic compound in the ether class with the formula (C2H5)2O, sometimes abbreviated as Et2O (see Pseudoelement symbols). It is a colorless, highly volatile, sweet-smelling ("Ethereal odour"), extremely flammable liquid. It is commonly used as a solvent in laboratories and as a starting fluid for some engines. **It was formerly used as a general anesthetic, until non-flammable drugs were developed, such as halothane**. It has been used as a recreational drug to cause intoxication. It is a structural isomer of butanol.
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Looking at its structure we can see that it is relatively simple - four carbons and, unlike most other incapacitating agents, it has no fluorine. I believe there is no living being that produces it, but due to its simplicity it is quite believable that some bacteria could produce it in an alternative world.
Perhaps bacteria in the gut of the skunk produce this ether.
This ether is relatively safe - most hospitals in Brazil, specially the public ones, reek of it. It will give you an euphoric high if you smell it on a piece of fabric and is a popular recreational drug to this day (we have a funny name for it as a drug: "lol lol"). In order to knock someone out, though, you need a high concentration. Still, ether is safe in that it knocks you out before you can manage to OD yourself.
Notice that at due to the high, skunk sniffing in your world might be the equivalent to our real world toad licking.
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Just to clarify, this is a serious question. I mean it. I'm legitimately wondering and am looking for feedback on this following question:
How close can an intelligent homonid species get to having anime girl proportions? Shoujo and moe girls are often complained about for having "unrealistic body types" and such on twitter. As someone whose studied these art-styles and also real-life human proportions, I'll admit, they can sometimes be a bit absurd. However, with the studies I've gone on the variety of shapes primates in general can be in, I get the feeling it's PLAUSIBLE we could get an uncannily anime-like female bodytype to function in real life physically and biologically.
General changes that would need to be made to the human shape to match these waifu types would include, from my general observations-
1. A thinly-built, lighter, lankier frame, with skinnier limb bones and narrow ribs. This goes beyond the scope of Marfan Syndrome and extreme ectomorphic body-types, and into the inhumanely thin frame territory. The only exception to this is the thighs and pelvis. If these changes were made to the human form, would the body still be capable of supporting whatever weight it has left? How much strength could a body like this possess? Would the density or structure of the skeleton or twitch-fibres of the muscles need to be altered in some way?
2. Extremely broad pelvises and hips. To contrast the light, thinly-built remainder of the body, anime girls often have proportionally broad pelvises (compared to a real-life girl of the same size, it can be argued their hips are actually the same. the anime girl simply has a thinner, narrower version of everything else)
3. Enormous Breasts. This one's kinda obvious, it's what anime girls are best known for. What would these breasts need to be made of to be supported on the thin spindly spines and waists of these hypothetical waifu homonids?
4. Proportionally large heads. Humans are generally 7 to 7 and a half heads tall, but these anime characters, despite being of similar height, are 5 to 6 heads tall, only occasionally reaching 7 or above. This means they, on average, have bigger heads than us. Combine this with the thinner neck, can such a head be supported at all? What changes would need to be done?
5. Facial Proportions: Considering that the size of the human brain isn't ENTIRELY decided by size (as people with pituitary disorders would come to prove), would it be possible to shrink the size of the brain (but keep it's neural network structure) to make room for the giant anime eyes? Speaking of which, the eyes of anime girls (or just "Moe" characters in general) have eyes set VERY low on their faces, similar to human infants, which further augments the feeling of their immense size. This, among other things, shrinks the rest of the face down. Can the mouth and nose afford to be shrunken down too? With a dramatically lighter body frame, it could be afforded to breathe in less oxygen.
Overall, the objective of this idea isn't to simply MIMIC the proportions of a Moe anime girl, but to uncannily HAVE them. Can a homonid species possess traits like these?
[Answer]
### We can get pretty close with plastic surgery
Maybe we've watched different anime; but points 1, 2, and 3, we can get pretty close with with existing humans. Thin waists, tiny frame, large breasts, big hips. These characteristics basically exist as a small percentage of the population naturally, and surgeries to reduce the waist and enlage the breasts are among the most common.
The eyes and face are the trickiest, but with a bit of [plastic surgery](https://www.google.com/amp/s/www.dailystar.co.uk/news/latest-news/manga-anime-japan-cosplay-fetish-17016994.amp) we can get pretty close.
[](https://i.stack.imgur.com/Hxy0a.png)
[](https://i.stack.imgur.com/avn8M.png)
[](https://i.stack.imgur.com/J9FEL.jpg)
[](https://i.stack.imgur.com/UTS2b.jpg)
[Answer]
[](https://i.stack.imgur.com/bDkbl.jpg)
Tarsiers (Tarsiidae) have what amounts to real-life anime eyes.
Most of the features you are asking about could be accounted for by some kind of neoteny (i.e., retention of juvenile traits into adulthood). Notably, larger heads, larger eyes, smaller noses, and shorter limbs are all symptoms of neoteny. It is also possible to mix neotenic and peramorphic (the opposite of neoteny, where the development of features is accelerated beyond the adult phenotype) traits in a single species, human skulls are heavily neotenic but we have a peramorphic nose and limbs.
Most of what you want with breasts, limbs, etc. could probably be achieved by shrinking the torso. The way in which the postcrania of anime girls differs the most from real people is that they don't have as elongate of a torso, which takes up 50% of our body. In real life the torso is three or more heads tall, but in anime characters it is often closer to two and a half.
Probably the biggest hurdle is going to be the neck. Anime girls typically have a much thinner neck than IRL humans, which will restrict the amount of space available for the windpipe, carotids, etc. Compression of the tissues in this region leads to IRL health problems like sleep apnea. Combined with the reduced jaws that may give your anime girls a population-wide case of sleep apnea.
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If I have lasers being used as a primary weapon for spaceships in a realistic sci-fi setting, what would the proportions of the laser cannon itself be? Presumably the cannon would be cylindrical, but I don't know enough about how lasers are generated to know if as lasers are scaled up, the cylinder would become proportionately longer and narrower, shorter and wider, or stay about the same. Modern combat lasers, like those being tested by the US Navy:
[](https://i.stack.imgur.com/YEIFw.png)
Look to be about man-sized, and about four times longer than they are wide. If I were to scale a laser up to the point where the lens was about 100 meters across, about how long would it be?
[Answer]
# Frame Challenge: Bigger Ain't Better
Why would you want a lens 100m across? Lasers are more capable of delivering power over distance the *narrower* their beam is. More importantly, anti-ship weapons wouldn't *have* lenses; nothing is sufficiently optically pure to allow the laser energy to pass through without destroying the lens.
You want as small a beam as possible with as much energy as possible, so a really effective anti-ship weapon would be *cm* across, not meters.
Your problem would be less one of scale, and more one of managing ridiculous quantities of energy before expelling them at your target. The goal is [Atomic Rockets'](http://www.projectrho.com/) [Ravening Beam of Death](http://www.projectrho.com/public_html/rocket/spacegunconvent.php):
>
> Let's take a 10 MW ERC pumped FEL at just above the lead K-edge. This particular wavelength is used because lead is pretty much the heaviest non-radioactive element you can get, and at just above the highest core level absorption for a material you can get total external reflection at grazing angles - so no absorption or heating of a lead grazing incidence mirror. We will use a 1 meter diameter mirror. The Pb K-edge x-ray transition radiates at 1.4E-11 m. This gives us a divergence angle of 1.4E-11 radians. At 1 light second, we get a spot size of 5 mm, and an intensity of 5E11 W/m2.
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> Looking at the NIST table of x-ray attenuation coefficients, and noting that 1.4E-11 m is a 88 keV photon, we find an attenuation coefficient of about 0.5 cm2/g for iron (we'll use this for steel), 0.15 cm2/g for graphite (we'll use this for high tech carbon materials) and 0.18 cm2/g for borosilicate glass (a very rough approximation for ceramics). Since graphite has a density of 1.7 g/cm3, we get a 1/e falloff distance (attenuation length) of 4 cm. Iron, with a density of 7.9 g/cm3, has an attenuation length of 0.25 cm. Glass, density 2.2 g/cm3, has an attenuation length of 2.5 cm.
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> At 1 light second, therefore, the beam is depositing 2E12 W/cm3 in iron at the surface and 7E11 W/cm3 at 0.25 cm depth; 1.2E11 W/cm3 in graphite at the surface and 5E10 W/cm3 at 4 cm depth; and 2E11 W/cm3 in glass at the surface and 7E10 W/cm3 at 2.5 cm depth. Using 6E4 J/cm3 to vaporize iron initially at 300 K, we find that iron flashes to vapor within a microsecond to a depth of 0.9 cm. The glass, assumed to take 4.5E4 J/cm3 to vaporize (roughly appropriate for quartz) will flash to vapor within a microsecond to a depth of 4 cm within a microsecond. Graphite, at 1E5 J/cm3 for vaporization, will flash to vapor to a depth of 0.7 cm within a microsecond (the laser performs better if we let it dwell on graphite for a bit longer, we get a vaporization depth of 10 cm after ten microseconds).
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> Net conclusion - ravening death beam at one light second.
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> Now lets look at one light minute. The beam is now 30 cm across. This is much deeper than the attenuation length in all cases, so we will just find the radiant intensity and the equilibrium black body temperature of that intensity. We have an area of 7E-2 m2, and an intensity of 1.4E8 W/m2. You need to reach 7000 K before the irradiated surface is radiating as much energy away as heat as it is receiving as coherent x-rays. The boiling point of iron is 3023 K, the boiling point of quartz is 2503 K, and the sublimation temperature of graphite is 3640 K. All of these will be vaporized long before they stop gaining heat. At this range, the iron is subject to 5.6E8 W/cm3 at the surface, the graphite to 3.3E7 W/cm3 at the surface, and the glass to 5.6E7 W/cm3 at the surface. Using the above values for energy of vaporization, we get about 0.1 milliseconds before the iron starts to vaporize, 0.8 milliseconds before the glass starts to vaporize, and 3 milliseconds before the graphite begins to vaporize (because of its long attenuation length, once it begins to sublimate, graphite sublimates rapidly to a deep depth, while you essentially have to remove the iron layer by layer).
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> Net conclusion - still a ravening death beam at one light minute.
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In summary, you wouldn't be widening the aperture, you'd be improving the *optics* and optical cavity to handle higher and higher energies, but keeping the actual emitter as small as engineering allows. The laser wouldn't get appreciably longer, but the energy systems would get *bigger*, presumably in pretty much all directions, to deal with energy flows and, importantly, *cooling*.
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Edit: Adding a resource for laser materials' damage, in a general sense, to illustrate what was going on in the comments: [Laser Induced Damage](https://www.rp-photonics.com/laser_induced_damage.html).
[Answer]
**Each would be a giant diamond crystal.**
[](https://i.stack.imgur.com/wrOyy.jpg)
<https://www.youtube.com/watch?v=qiAtCLHFep8>
You have a lot of little laser pump beams. They combine their energy through a diamond and emit one giant beam, Death Star style. Little pump beams might escape out the side so give this things some space when you fire. You get your enormous diamonds from the correct atmospheric level of a gas giant, where you can find them bobbing around. You have a team of Ugnaughts to carve each into shape. You carry a supply of spares.
Instead of a bunch of phallic protrusions from your ship (not that there is anything wrong with that) you have refracting giant diamonds, which your CGIsmiths make reflect and refract the ship next to it as well as the flashes of light from the space battle. Your ship looks like a crown studded with jewels. If that has been done I have not seen it.
[Answer]
No, no cylinders. The most optimal path is to hid your laser-generating part of the setup in the hull, leaving outside only a rotational mirror turret. Like that:
[](https://i.stack.imgur.com/0XyL8.png)
Do away with the useless in space aerodynamic shell, and you're left with this:
[](https://i.stack.imgur.com/d2qHQ.png)
(The flaps are for the protection of the mirror from micrometeorites or the enemy and are closed in any instance the turret isn't lasing at a target)
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**Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers.
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You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49).
Closed 3 years ago.
[Improve this question](/posts/192752/edit)
Dave lives in a world where superpowers are extremely common, lending to the creation of superpowered crime fighters to combat the superpowered crime doers. What makes Dave special is that he has a unique ability, he can mimic the form of anyone whose blood he consumes while said blood is in his stomach. This even goes as far as to allow him to copy the powers of those whose form he assumes.
While this initially struck him as a perfect power to fight crime, now that he's begun his quest to fight crime, he's quickly learned how unreliable his ability is. As he needs the blood of others, he'll need a consistent way of getting that blood: in addition he has no idea what medical conditions he is going to be stuck with while mimicking the target. To add to the chaotic mix, there's no way of predicting what abilities the superpowered criminal he's fighting will have and in turn, what ability he will be copying.
All in all, Dave needs to be even more prepared than any other superhero. He'll need not only a method of extracting his opponent's blood, but also a uniform that will allow him to take advantage of whatever dice roll he gets when copying someone and their abilities.
To put it shortly, how can Dave best ready himself before engaging in crime fighting, to best insure his safety and success?
As requested in the comments, some clarification on the nature of Dave's ability:
* Dave requires non-coagulated human blood to be able to transform into someone.
* As the effect only lasts while the blood is in his stomach, each dosage typically lasts him more or less 20 minutes. The effect cannot be canceled or stopped short of knocking Dave out or the time limit passing.
* Dave's job as a Superhero pays well, but he'd gladly put himself through another job if it aided him in his Hero work.
[Answer]
**Dave will mimic his allies.**
How the heck are you going to get the blood of your enemy? What are you, Nosferatu? Plus what good it is to mimic your enemy? Maybe if Dave was a spy master that would be useful but if he is duking it out with Dude, Dude is not going to hold back because Dave looks just like him. Dude knows Dave is not Dude and will make this clear with kickings and punchings.
No, you need a bunch of little canisters of preserved blood from folks you know. Ask them nicely and do them favors, and collect the blood in a clean medical facility. People with good powers. Strong dudes. Ninja masters. Little old ladies. Harmless kids. High ranking worldbuilders. All of those, perhaps arranged for easy access in a Chewbacca type bandolier.
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First, some context: I am creating a habitable world with intelligent life present in the second main sequence of a star (hence why it needs to be re-stabilized). This life discovers the ruins of an old civilization that had reached about modern humanity's tech level that had gone extinct thanks to the red giant/sub-giant phase, and finds out that their time is limited, which is where the actual stories start. I do not wish for alien civilizations to get involved, however I do not care how unlikely the process is, as long as its natural and reasonably possible under known physics.
Now, the question: How do I achieve this? The post-giant star needs to have a similar (maybe slightly higher) luminosity of the original star, or at least the planets orbit needs to have been changed by the event such that it is habitable. The best thing I can think of is some sort of external force (perhaps a super earth or near miss with a star corpse) that causes the star to become more convective and supply the core with fresh hydrogen to fuse, however I am open to any possible explanation for a red giant to enter a second main sequence whilst the planet stays habitable.
[Answer]
As you guessed, we'd likely need to make the star fully convective in order to move it to a sort of second main sequence, where hydrogen fusion begins anew at its center; it's imperative that the hydrogen-rich outer layers are allowed to mix with the hydrogen-depleted core. Ideally, this would happen sooner rather than later. Stars which become red giants typically spend up to a couple billion years as *subgiants* immediately after the main sequence, entering the red giant branch only when their cores become degenerate. Your civilization would want to restart convection before that occurs.
Let's talk about what gives rise to convective zones in stars. There are three mass ranges to consider:
1. Stars with masses less than approximately $0.3M\_{\odot}$ are fully convective and therefore actually never become red giants. The thorough mixing allows them to exhaust all of their hydrogen by the end of their (extremely long) lives. Their convective zones consist of the entire star because their low temperatures give rise to high opacities, and high opacities are quite conducive to convection.
2. Stars that fall into the range $0.3M\_{\odot}\lesssim M\lesssim1.3M\_{\odot}$ (the outer boundary is uncertain), like the Sun, have radiative cores and convective envelopes - again, low temperatures imply high opacities, but here the cores are too hot, and radiative transport dominates in the inner regions.
3. Stars with masses greater than $\approx1.3M\_{\odot}$ have the opposite structure: convective cores and radiative envelopes. This is the critical mass at which the CNO cycle, rather than the proton-proton chain, becomes the dominant mechanism for hydrogen fusion. The CNO cycle's rate has [a much higher temperature dependence](https://websites.pmc.ucsc.edu/%7Eglatz/astr_112/lectures/notes8.pdf), with $\varepsilon\_{\text{CNO}}\propto T^{20}$, while $\varepsilon\_{pp}\propto T^4$. Therefore, the CNO cycle implies a much higher temperature gradient than the p-p chain - and a higher temperature gradient is the other major factor that can lead to convection.
Red giants have more complicated structures. Their degenerate cores and shell burning regions are surrounded by an intermediate radiative zone, and finally the enormous convective envelopes they're best known for. Fortunately for us, these convective zones are far from stable. Indeed, at several points in a red giant's evolution, the star experiences what we call [*dredge-ups*](https://en.wikipedia.org/wiki/Dredge-up), there at convective envelope reaches deeper into the star and actually mixes some of the byproducts of fusion up to the surface. In short, evolved stars may be susceptible to some poking and prodding, and I suspect that the same might be true for subgiants.
Let's look, then, at what I'd guess are our two main options. Helium fusion via the triple-alpha process has an even stronger temperature dependence, at $\varepsilon\_{3\alpha}\propto T^{41}$. That might seem conducive to convection, if it could be exploited. On the other hand, that's helium fusion, not hydrogen fusion; as such, it basically defeats the whole purpose of trying to jump-start a second main sequence!
Perhaps we could attempt to raise the opacity in the radiative zones of a subgiant's envelope - whether they be more akin to those of a red giant or of a massive main sequence star. It seems unlikely that we could manage to reduce core temperatures significantly, but perhaps instead would could change our opacity source. Unfortunately, radiative opacities (with the exception of temperature-independent Thompson scattering) tend to decrease with increasing temperature, as noted above, sometimes as severely as $T^{-7/2}$, in the cases of free-free, bound-free and bound-bound absorption. (They do, though, tend to increase with density!) An exception is electron scattering, ordinarily the major source of opacity in the radiative zone.
My proposed solution is to attempt to increase the metal content of the radiative zone. Most radiative opacities show linear or quadratic dependence on the mass fraction of metals in the gas; therefore, raising the fraction of heavier elements, $Z$ would increase the opacity. [These notes](https://www.astro.princeton.edu/%7Egk/A403/rg.pdf) indicate that in the scenario where electron scattering is the dominant source of opacity, the temperature and density are related to the mean molecular mass $\mu$ by $T\propto\mu$ and $\rho\propto\mu^4$. I believe that these two dependences mean that changes in temperature and density caused by changes in molecular weight would cancel out, and it's just the explicit $Z$ or $Z^2$ dependence that governs opacity changes.
How could we do this? Perhaps crashing several spare (!) terrestrial planets into the star would help; there are cases where a star has exhibited a noticeably higher metal content that appears to come from engulfing a planet. Ideally, if the subgiant's convective zone was deep enough, metals could be mixed downwards to the upper edge of the radiative zone; from there, it's possible that they could enter the zone itself.
This is all fairly handwavy, but it's not outside the realm of possibility. Increasing opacity could, at the very least, make it more favorable for convection to become more important in any radiative regions, and if the civilization gets lucky, perhaps hydrogen could get mixed into the core before it becomes degenerate. I don't know how to calculate the relevant timescales to determine how long this weird reborn star could stay on its second main sequence; I suspect it wouldn't be incredibly long, but it depends. Like I said, maybe they'll get lucky.
[Answer]
**The planet's orbit changes to be farther away.**
Your red giant will lose mass.
<https://en.wikipedia.org/wiki/Stellar_mass_loss#Red_giant_mass_loss>
>
> Stars which have entered the red giant phase are notorious for rapid
> mass loss. As above, the gravitational hold on the upper layers is
> weakened, and they may be shed into space by violent events such as
> the beginning of a helium flash in the core. The final stage of a red
> giant's life will also result in prodigious mass loss as the star
> loses its outer layers to form a planetary nebula.
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>
>
As the mass of the star decreases, so does its gravity. The velocity of the planet does not change. With same velocity and weaker gravity, the planet will move to a wider orbit around its star.
[http://curious.astro.cornell.edu/our-solar-system/57-our-solar-system/planets-and-dwarf-planets/orbits/81-when-the-sun-converts-mass-to-energy-do-the-orbits-of-the-planets-change-advanced#:~:text=How%20does%20this%20affect%20the,it%20in%20the%20same%20orbit](http://curious.astro.cornell.edu/our-solar-system/57-our-solar-system/planets-and-dwarf-planets/orbits/81-when-the-sun-converts-mass-to-energy-do-the-orbits-of-the-planets-change-advanced#:%7E:text=How%20does%20this%20affect%20the,it%20in%20the%20same%20orbit).
>
> How does this affect the orbits of the planets? Intuitively, if we
> imagine a planet orbiting the Sun at some speed, as the Sun loses mass
> its gravitational pull on the planet will weaken, so it will have
> trouble keeping it in the same orbit. The planet's velocity will
> therefore take it further away from the Sun, and the orbital
> separation between the Sun and planet will increase.
>
>
> The formula that governs this situation turns out to be that the
> orbital separation is proportional to 1 divided by the Sun's mass --
> this can be derived from the fact that the Sun-planet system must
> conserve its angular momentum as the Sun loses mass. The orbital
> period of the planet, meanwhile, is proportional to 1 divided by the
> Sun's mass squared.
>
>
>
The event that gives your planet a good fry might be an ejection of a lot of hot mass from the star. But the planet is not cooked thru and thru and not enough to lose its atmosphere and water - maybe more of a dark toasting. The planet moves away and has time to cool. Life has found refuge in the deep places and can start anew.
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On Earth, there are far more insects by biomass than any other creature type. Not only that, but they constitute a wider variety of species too. As a result, they also evolve interesting mechanisms unique from animals. That is, it is easier and more common for insects to be bioluminescent compared to large animals. **If I wanted to create a planet that favored larger species and possibly non-insectoid species, how would I go about that?** Would increased oxygen favor large animals? Or is it the type of biome that matters?
**Criteria:**
* Insects are NOT the largest by total biomass
* It is more efficient, possible, likely to be cat-sized than cockroach-sized
* Solution must be chemical, biological, or environmental in nature (no planetary changes outside of Earth's current systems)
* The planet must still be habitable for humans (non-advanced special equipment like fur coats is acceptable)
**Bonus Points:**
* The solution benefits non-insectoid species (fuzzy animals are more common)
* Does not involve "cuz evolution" (preferably a physical phenomena that causes the larger creatures, avoiding the claim that with evolution anything can happen)
[Answer]
If your sole purpose is to leverage the advantage towards larger creatures, then you have two pathways to do so:
1. **Decrease** the air oxygen content.
[Insects have very inefficient "lungs"](https://en.wikipedia.org/wiki/Respiratory_system_of_insects), that only really work by absorbing oxygen directly from the air. This severely limits the size that insects can attain.
Animals with lungs have the ability to extract much more oxygen from the air, due to the dedicated, protected and complex internal structures of their lungs.
So, lower oxygen in the air makes your insects smaller, and weaker. But would only make your lung-breathing complex animals less energetic.
2. **Lower the temperature** to just below freezing. Often.
Insects are too small to survive a frost, other than by cowering in a communal nest or otherwise finding shelter from the cold. Larger animals have very little problem with the cold, as long as it does not get *too* severe or last excessively long.
The problem is that insects, and the myriads of smaller living thing people would just call "bugs", even down to the microscopic dust mites in their uncounted trillions in your home, serve a **valuable ecological purpose**. They are the scavengers, and the soil-turners, and the hair-devourers. Without them, we would eventually be up to our armpits in hair, and cellulose, and dead skin flakes.
If you remove or seriously reduce the numbers of such "bugs", you will need to invent something else that serves the same purpose. For all the myriad little tasks, in the little crevices and under the soil. Something small, that breeds quickly, that spreads everywhere. Something that is mobile, and burrowing, not just a sessile garbage eater, or you create fungus forests. Ideally something that can fly, to distribute itself to locations where it is needed. Something like... oh dear, you've re-invented Bugs again.
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## You need stability.
Evolution tends to favor larger size on average, all other thing being equal. Larger size leads to greater efficiency of resources and better robustness (sequestration) of resources even if the total amount of resources needed is greater. 100lbs of cow uses less energy than 100lbs of rat. This is *why* larger organisms have evolved over and over and over again.
However smaller animals will always drastically outnumber larger ones because there are more small (low energy acquisition) niches to fill, and there has to be more low energy niches due to how trophic level energy distribution work. Larger animals will never reach combined total mass greater than small ones. There just is no realistic way to make the energy distribution work.
Small size often also means faster breeding which leads to better aggregate survival in drastically changing conditions. This is why it is always small animals that survive mass extinctions. Dinosaurs and birds are a great example as long as conditions are stable dinosaurs kept getting bigger and bigger (we see the same thing with mammals) but it is always the smaller sized ones that survive mass extinction. Now don't get me wrong, more small animals die during mass extinctions than large ones becasue there are more of them, but becasue there are so many species and individuals of them and their resource needs are so low there are always some that survive.
**You can the most large organism by having stable conditions, but they will always be the minority of the total mass.** this is why life has evolved megafauna over and over again, as long as conditions are stable on the long terms large animals have an advantage because they can better survive short term fluctuation, but as soon as long terms conditions become unstable that advantage disappears. But even when conditions favor the large they still make up a minority of the biomass because even though they are more efficient they need more total resources and cannot change as quickly.
Heck single celled life out mass all multicellular life combined by several orders of magnitude for the same reason.
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Megaladons were apex predators until climate changes affected the key aspects of their viability.
1. Food sources became more scarce; as tropical temperatures in waters became more scarce, the food sources either perished or adapted to colder climates.
2. Breeding grounds became less accessible; as ice caps moved in, shallow waters where a megaladon in heat could have its calf safely became more and more scarce.
If you look at the largest animals, they all come from singleton offspring situation. Large litters typically happen in "boom or bust" environments, wherein a large amount of offspring are yielded, but depending on how the environment is, very few will survive. The offspring in stable environments also tend to have longer "helpless" phase after birth (like a Megaladon for instance!).
Another interesting thought about this is that if you look at the general trend of humans, you see that they are getting (a) taller and (b) smarter. That isn't necessarily because of "evolution" either, probably more due to better nutrition and overall health. Stunted growth tends to affect populations that struggle with sustenance or some type of injury.
What I'm trying to get at is if your world is on an earth-like planet, the easiest way to affect the size of creatures is to create a world without any serious changes in the overall environment for some period of time (say a hundred thousand years). Life, uh, finds a way. Then, come up with a food of which there is an overabundance. The longer the climate remains static in such an environment, the more likely it is that the overall size of all animals becomes larger. The safer it is to care for your offspring, the easier it is to have a singleton approach, which also trends towards larger animals.
Hope this helps!
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much more oxygen and energy, the oxygen, because the quantity of vegentation, or vegetation like creatures, and energy from a star powerfuller than ours, and, to survive predators, the animal becomes bigger and the predator becomes bigger to kill the prey, a lower gravity would be very usefull, as the lower the gravity, the less the weight, the less the energy needed to move it, something like this happened in our world, when there was a lot, and i mean a lot, more oxygen, bugs (yes, yes, you said no bugs) became the size of hummans and more, Meganeuropsis permiana, is one of them, they had to stop growing, or they couldn't support their exoskeleton, so here the lower gravity in your plnet comes in, they need less energy as the exoskeleton wheighs less, so they can keep growing
chemical, by using voids and/or hydrogen etc. the total surface area could be bigger than a whale, but still wheigh the same as one, also, continuing the hazards, etc. in this other answer, a hazard which makes animals develop so big would be the need to get away from land, but, you cannot develop wings, the answer searched by evolution would be flight, a bit like here [Plausibility of Floating Whales](https://worldbuilding.stackexchange.com/questions/96644/plausibility-of-floating-whales/191717#191717%5B1%5D) thank you for your time, sorry for any misspelled words, spanish keyboard
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# Non-native life, ecological catastrophe and noxious chemicals:
**Hazards**: Perhaps your environment has harsh factors that damage life forms which are small. There could be waves of toxins that poison everything, but are absorbed through the surface. Small animals have a large surface area per unit volume. Perhaps survival is dependent on being able to survive acid exposure - the acid gets into all small spaces, and across the skin. Insect-like creatures would dissolve, but creatures with some kind of moisture-resistant coating are burned but live.
**Mass extinctions**: Even a single extremely large bottleneck could wipe out all existing tiny creatures, and it could take thousands or millions of years for tiny things to re-evolve from bigger ones. Let's say a virus that affected all insects killed all of them but had a reservoir in larger species. All of them would die, then all their eggs hatch and all of them die again. Mass extinctions happen. A major change to the environment could expose a weakness in the otherwise successful small organisms. For example, if the planet had never experienced cold, the small organisms might all freeze to death and have no mechanism to compensate, while larger organisms had more body mass and managed to not go extinct before the climate stabilized.
**Migration**: Or perhaps the life on the planet comes from somewhere else. The colonizing animals are either microscopic or large. No bugs made the journey. The body plans of many large animals might not be well adapted to becoming small. A rat might be able to eventually become a shrew, but a lion might find it a harder evolutionary process.
There are eventually going to be evolutionary advantages to small size, and mechanisms will compensate over time. But in the meanwhile, live large!
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It could be argued that we already have biological EMPs in the form of solar flares.
But what I'm looking for is a sort of a half baked idea for a planet the had life forms that produce natural EMPs.
So for the context, barely matters but here it is, a space exploration ship gets marooned on a faraway planet of which they know little. The ship takes a lot of damage so their anti EMP technology is not working for the moment.
Now the surprise comes when they land, more like crash, and after a while most of their electronic are fried.
Now I did not set this to hard science because I'm not sure if it could be done but I'd really appreciate a detailed breakdwon of the proposed life form that produces EMPs.
That life form has to cover most of the planet so it can't be just one animal small or big.
However groups of animals, or birds for example, that naturally produce EMPs would be welcome.
Trees, fungus, special rocks or crystals...etc are all welcome suggestion.
However I just want that to make sense. So what I thought of is that life form on that planet "evolved" to produce EMPs to protect themselves from the original inhabitants. I think this starts to make sense as they can't just start spending energy for no gain. **But this is merely and idea and not in any part a limit or a hard must.**
Anyway I think some sort of incredibly large animal or life form, maybe a sort of huge sprawling trees that cover kilometers of land, can produce those EMP who need to be enough so that the humans stranded need to stop it before they can start fixing their stuff.
So all I want is periodic or constant EMPs enough to make electronics useless, whatever animal or life form that makes it is completely up to you. Solar flares are not welcome as I think it is too boring.
And as always an explained "No" is as valuable as ever.
So. Is there a solution?
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**No**
An EMP is an electromagnetic (EM) field that (in this case) induces a current into wires. This can do three things to harm your electronics. It can be read as a legitimate signal by the computer, masking the real code instructions. It can charge memory, corrupting it. It can burn the wire. The first two are generally harmless. Code is often corrected in processors and a reboot is sufficient to combat this effect if it's worse. The second one is the most dangerous and requires (part of) the electronics to be replaced. This is the one you want ("their their electronic are fried").
To burn a wire, you need one thing. To increase the wattage. The wire has a resistance that will stop a bit of the electrical signal. That means part of the wattage isn't moving on as electricity, but becomes heat. This heat then needs to become high enough to melt the conductive wire, or able to melt the protective layer of it and a neighbouring wire to short circuit.
Using EM to induce current isn't an easy task. The larger the distance, the more difficult it becomes. Lets take a look at the electric eel. It can generate up to 860V and 1 ampere. This might seem a lot, but your average wire to an appliance can take a lot more ampere, which is more impressive. A shock from 230V and 16A from your average EU wall outlet is much more dangerous. Don't get me wrong. An electric eel has the electric potential to severely shock horses to scare them away. But this is on direct contact. If you want it to disrupt a circuit with an EMP, you'll lose energy in both the translation of body energy to EMP and then the translation of EMP to electricity. Then the electricity needs to be high enough that due to the resistance of the wire it heats up enough. It would require a ludicrous amount of EM, which could probably be picked up by the crew themselves as well by the queasy feeling.
I had the same idea as @L.Dutch-ReinstateMonica. If you get an event like mating season where *literally* several ton in biomass of creatures get together and to scare off/hunt/defend themselves they generate a huge magnetic field. Especially on a planet where electro senses like the electric eels are very common, such things might help to disorient of disable predators. Still, the amount of energy required is ludicrous and very unlikely. They probably need to land on a hot spot for it to have the desired effect.
As an alternative, consider shifting of magnetic poles of the planets core. No idea if those can generate EMP and some geologist or astrophysicist might be better to ask, but as its a planet it'll probably be able to create huge amounts of EMP on it's own under certain circumstances.
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SInce you allow "crystals", there is a fairy common natural phenomenon that produces EMP - tiny $H\_2O$ crystals produce a lot of static electricity that is then [discharged](https://www.nasa.gov/audience/forstudents/k-4/home/F_What_Causes_Lightning_Flash.html) against the ground. Just make it bigger, more frequent etc. on that planet. Or even not, since here on Earth it is usually powerful enough to fry any electronics around, even with induced current alone, no direct hit is necessary.
Your spaceship would be exceptionally vulnerable, since I assume it is 1) tall and 2) has a lot of metal parts.
Alternately, if looking specifically for something biological, let an [eel-like](https://en.wikipedia.org/wiki/Electric_eel) (but land dwelling) creature wander into your control room and discharge.
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A possible way to make it biologically produced would be to have some animals with capabilities similar to electric heels use their electric discharge as part of their mating ritual.
When the mating season comes the environment is filled with their synchronized discharges, which summing up also amplify their effects.
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I was doing some tests in Universe Sandbox a while ago and I noticed a strange behavior shown by giant planets on highly inclined orbits. In the simulation I placed an Earth at 1 AU around the Sun, and with an inclination of 0 degrees, and a Jupiter in a 2:1 resonance with Earth. The Jupiter was also at an orbital inclination of 20 degrees. When I ran the simulation, things seemed normal at first. However, I soon noticed a pattern with the Earth's movement.
In a period of around 100 years, the Earth's orbital inclination increased to around 40 degrees, then decreased again. It then continued until its orbital inclination was around -40 degrees and then increased, spanning a time of 2 centuries per cycle, which i dubbed "Inclinatory Cycles". I tested other things too. With further tests I concluded that the Earth will always deviate from its base inclination by twice the giant's inclination on each cycle, and that the higher the mass and the closer the giant, the faster the cycle.
So, I was wondering if these "Inclinatory cycles" could be used in seasonbuilding. After all, more extreme inclinations lead to more extreme seasons. I can imagine an intelligent species realizing that for half a century, the seasons get more extreme, with hotter summers and colder winters. and for the other half, they get less extreme. Seasonal floods in rivers from the melting poles during an extreme summer could be the telltale marking, and this could be used for agricultural purposes. Now, my question is: Is this setup with a highly inclined gas giant even possible, and what would be the ramifications it would have on agriculture?
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You don’t even need the gas giant. It is believed that [resonance effects with the moon as it recedes from the Earth can cause large fluctuations in the Earth’s axial tilt](https://ui.adsabs.harvard.edu/abs/1982Icar...50..444W/abstract), so all you need is a planet with a large moon that’s a bit further away from it.
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I don't see any reason why this wouldn't be possible.
As for the impact on agriculture, the people might have to do cyclical migration: moving closer to the equator when the tilt is more extreme & maybe back out when it's less extreme. The crops that the people would be able to grow would change in tune with the cycle.
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The ramifications it would have on agriculture are the same as it would have on the ecosystem in general: life would have to be adapted for such swings. (This means that any agriculture would be based on the wild things that already are adapted.)
Some plants, or even animals, might go dormant for the extreme period. (For a period this long, they are more likely to be insects in egg or pupae stage.) Others might take advantage of the extreme period to avoid the competitors and go dormant as the weather grew more even.
Migration toward and from the equators is possible. It's on a time frame such that animals (such as humans) could manage it, and even plants that grow on a short time frame by spreading their seeds wildly.
Some species might adapt to all seasons. This would probably require such things as shedding fur for animals, and ability to take both severe drought and flooding.
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In the project I am working on, the main race in my setting has the body plan similar to a primate, and has somewhere between a moderate, or highly arboreal lifestyle. (Haven't quite settled on this yet)
Recently, I stumbled upon the topic of human throwing, and how large of a role it played in human evolution. Essentially, changes in our shoulder structure allowed for more arm mobility during throwing, allowing us to hunt and consume a higher quantity of meat in our diets, which helped in brain development. *The problem I ran into with this, is that I want my race to maintain both arboreal-proficiency, and the ability to accurately and powerfully throw, which so far appears to be two contradictory actions.*
With an **ape-like shoulder structure**, where the arm's hinge is positioned upwards from the shoulder, it allows for good swinging and climbing, however, limits the upper arm's ability to rotate during the throw, making powerful throws essentially impossible. With a **human-like shoulder structure,** where the arm is perpendicular to the shoulder, it allows the upper-arm to greatly rotate, and therefore allows powerful throws, however makes humans somewhat mediocre climbers, at best. I am aware that humans are able to climb, and pretty impressively too, but compared to apes, there is essentially no competition, and physically, humans expend much more energy doing so. **Is there a good middle-ground structure that allows proficiency in both actions?** Or would a potential shoulder structure like this just lead to mediocrity in both?
[Answer]
***Tools:***
I think you can probably use tools to compensate for this deficiency. [Neanderthals](https://www.smithsonianmag.com/science-nature/neanderthals-hunted-groups-one-more-strike-against-dumb-brute-myth-180969472/) had joints that also limited throwing. Their bones have injuries in a pattern also seen in people who perform in rodeos - the kind of injuries you get when in close contact with large, angry animals. But they also used strategy to compensate with cooperative hunting. The suggestion is that much of their hunting was based on [closing](https://www.nature.com/scitable/knowledge/library/neanderthal-behavior-59267999/#:%7E:text=Neanderthals%20were%20consummate%20hunters%20of,their%20tips%20(Shea%201988).) with animals to finish them off. So it's possible for hominids to evolve as hunters and yet still not be great throwers.
But once you have reasonably evolved tool users, they can make better tools to compensate for their limited range of motion. The [Atlatl](https://en.wikipedia.org/wiki/Spear-thrower) was essentially a stick to increase the relative length of the arm, amplifying leverage. Sharp stone tools reduced the amount that you needed to hit hard, instead amplifying the effects of cutting. Similarly, [slings](https://en.wikipedia.org/wiki/Sling_(weapon)) amplify force but wouldn't require the same huge range of motion.
I'll take a stab and guess your brachiators will hunt from trees, emphasizing the importance of patience and ambush. Early humans [hunting in arboreal environments](https://natureecoevocommunity.nature.com/posts/44345-specialized-arboreal-prey-hunting-by-early-humans-in-sri-lanka) may have concentrated on smaller prey, not requiring the large force of a heavy spear Maybe their range of motion still allows strong throws downward. Their strength might allow them to emphasize using weight (like dropping rocks) or jumping on prey from above with spears. They could hunt with traps, or nooses, or drop nets from above. Even simply digging covered pits and driving animals into them enables hunting. Once the bow is developed, your need to be a great thrower will be largely supplanted by this ultimate leverage amplifier. The advantage of ranged weapons is at least somewhat limited in a forest environment compared to open plains.
If your hominids are smart, their brains will compensate for any apparent limits to mere throwing.
[Answer]
See this question:
[What would a creature with very powerful and accurate throwing ability look like?](https://worldbuilding.stackexchange.com/questions/184297/what-would-a-creature-with-very-powerful-and-accurate-throwing-ability-look-like/184326#184326)
Basically the point is made that powerful throwing ability need not require stronger and stronger muscles, it requires fancy brain circuitry to handle the timing and rhythm necessary for an optimal throw.
So design your creature for good climbing ability, and then give it a human-ish brain, including human rhythm.
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Humans already have this. The difference between human and great ape shoulders is less due to climbing behavior and more because gorillas and chimpanzees knuckle-walk. Indeed, it's been suggested that part of the reason why humans became bipedal was to be able to efficiently walk on the ground without sacrificing dexterity in the forearms. Knuckle-walking involves a suite of changes to the arm and shoulder, including [an inability to pronate the wrist in a flexed position](https://anatomypubs.onlinelibrary.wiley.com/doi/full/10.1002/ar.23743) (which is kind of useful if you want to have dextrous hands). [Human shoulders and hands are actually a lot closer to the ancestral ape condition than those of gorillas, orangutans, or chimpanzees](https://www.pnas.org/content/112/16/4877).
Look at gibbons, [who have a shoulder a lot more similar to a human than any other ape](https://link.springer.com/chapter/10.1007/978-3-662-45719-1_1) (their shoulder joints are more flexible to enable more range of motion, but they have less dexterity and strength as a result). Other changes in the shoulder and hand, like a reduced thumb, are more because gibbons swing hand-over-hand, which is a mechanically unusual and specialized behavior in its own right. The reason humans are poor at climbing has less to do with our shoulder structure and more to do with the fact that we have very long legs that lack an opposable big toe because we are so terrestrially adapted. Humans have a very specialized skull and body from the hips down, but our arms are perhaps the most unspecialized thing about us and are still really good for climbing by themselves.
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I'm working on a world for a miniature wargame, sci-fi/fantasy genre. One species will have the ability to live as fully land dwelling, fully water dwelling or like amphibians. I've given them both lungs and gills, but I've not yet gone deeper into how that will work. My main problem is that the skin of (most) land dwellers won't take kindly to too long in water, while the skin of water dwellers and amphibians will rapidly dry out on land. How could I make this work?
My basic idea is that some bodily function could change the properties of their skin, possibly connected to whether they are currently using lungs or gills to breathe, but I can't seem to come up with a reasonable explanation.
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**Almost Anything Will be OK**
As people mentioned penguins and otters are both fine for extended terrestrial and aquatic life. Same goes for several species of toad. The sea iguana in the Galapagos likewise does very well both on land and in the water for extended periods. Even some fish can survive a certain amount of time out of water (hours mostly, but occasionally much longer) as long as they stay moist (usually via mucus membrane/secretion). There are species of crab that live on land and in the water, and some full time land. I can't think of one that goes extended periods in both environments, but as coconut crabs (the largest land-dwelling species) drown rather than suffer some sort of shell damage so I assume that's more a product of not having gills and air-breathing lungs more than anything else. At any rate the aquatic crabs live on land quite handily as long as their gills stay moist, so give one lungs and it seems like it'd be fine indefinitely! I can't think of an insect that routinely lives both in and out of water without pupating/metamorphosis, but even so that's the main types of "physical design" (fur, feathers, scales, skin, exoskeleton) taken care of with real life examples.
In the end I think extended survival of a species on land or in water comes down more to "can it breathe" than intricacies of the skin that are likely beyond the scope of a wargame. If it's got the equipment to breath air and water the rest is covered!
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I am not too knowledgeable on this subject but my first intuitive answer would be to look at something like penguins or otters? I know penguins are fine for months without going into the water, and they are also fine swimming for long periods of time.
Otters have special fur to protect them against water while they swim.
So if you are ok giving them feathers or fur both of these options seem realistic.
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**Slime coat.**
Aquatic vertebrates are slimy. The slime coat protects skin from water and serves like second dispensable barrier to the environment.
Lungfish can transition from water to land and the slime coat helps with this, hardening to prevent moisture loss while on land.
Your creatures could be similar. The are slimy and slick while in the water, and when out for any length of time the slime coat hardens into a cracked and scaly carapace. They can regenerate the slime from their bodies to keep the coat functioning while on land.
These might be fairly thirsty creatures.
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How would living organisms develop/evolve in a very-low g ocean environment?
The environment would be a small radioactive core surrounded by a small mass of water, less than 100 km in diameter, in the center of the L4 or L5 Lagrangian point between a very large planet and a large moon.
The body of water would be held together by surface tension, the forces of the Lagrangian point, and a thin outer layer of ice.
The water is kept liquid from the heat of the radioactive core.
The moon provides sufficient amounts of radioactive material, water, nitrogen and carbon in a similar fashion to how [Enceladus provides the material of Saturn's E Ring](https://en.wikipedia.org/wiki/Enceladus#Source_of_the_E_ring), such that the body of water keeps a stable amount of water, the core receives new radioactive material as the old one decays, and life has the materials to develop.
The large planet has a strong magnetic field protecting the body of water.
**How could/would solid or liquid multicellular life forms develop in a body of water without substantial gravity?**
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On one side for a micro organism floating in water, gravity is almost non existent. Being made mostly out water, they simply float in the liquid and are carried around by currents.
On the other hands the lack of gravity will greatly influence the distribution of nutrient: while on Earth any dropping falls to the bottom sooner or later, in microgravity everything, from a rotting corpse to the feces of any other organism would stay in place.
This would mean that transport of nutrients would be greatly limited by only intermolecular diffusion.
As a reference, stagnating waters on Earth are often abiotic or very poorly livable, due to this very issue.
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**Life growing from the cracks.**
The stuff to build meat will be scarce in these waters. As it is in open ocean, but maybe scarcer than that - at least in open ocean there is the possibility of blown dust, or elements from the sea floor welling up. On this lonely droplet there is none of that.
Perhaps you could have this water in a cloud of space carbon and nitrogen; [tholins](https://en.wikipedia.org/wiki/Tholin) raining down onto the planet surface. I could imagine they might accumulate on the ice, as might be the case for Saturn's icy moon Enceladus.
<https://astronomy.com/news/2017/01/gunk-enceladus-surface>
[](https://i.stack.imgur.com/JSiAS.jpg)
<https://www.nasa.gov/mission_pages/cassini/media/enceladus_cracks.html>
When a crack forms in the ice, that material becomes available to the life beneath. It is an upside-down deep smoker. Instead of rich materials ejected from the deep earth and made available to the sea dwellers, rich materials will fall thru the ice cracks and become available.
I could imagine a tangle of life hanging down from these cracks as they open or close. Primary producers work chemistry on the tholins as they thaw. Heterotrophs feed on the primary producers. Spores or planktonic forms are released into the bottomless ocean, to drift until they encounter another lifegiving rift in the surface.
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