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**Background**
I'm developing 6 to 10 sapient alien races for a short story.
**Basic Story Setting**
The short story takes place in the Milky Way sometime in the next 1000 years. These races will be at roughly a Star-Trek / Star Wars / *Pandora's Star* level of technology, i.e., circumnavigation of the galaxy still takes a "long time", but any species worth talking about has FTL capability of some kind.
All sapient alien races will have their original, naturally evolved biological forms, because strong genetic engineering / nanotech / digital immortality will be impossible (by hypothesis) in this particular story. However, other than that, I would like to write these alien races as realistically as feasible in a short story.
**My Concerns**
If I had to sum up my concerns about my story in one sentence, it would be this:
*I want to write this short story as with as much scientific realism as practical.*
I anticipate the story exploring 6 to 10 specific alien races, though hundreds or thousands more will exist in the background setting. I've heard that most life is likely to be carbon-based, because of the unique chemical properties of carbon compared to other elements (*if that's wrong, please tell me!*). So most or all of the races in the story will be carbon-based. However, it doesn't feel "right" to make all the races both carbon-based *and* oxygen breathers.
Some of them will probably breath oxygen, but I worry that having all of the primary 6-10 species breathe oxygen would feel too "same-y", or would break the reader's suspension of disbelief. It would be odd that they all breath exactly the same, despite having radically different bodies and minds. And no, there is no galaxy-scale "panspermia" process in this setting, so they wouldn't all have similar biochemistry due to a shared origin.
They don't need to all be completely different chemically, but it just "feels responsible" to have maybe two or three of them (at least) be based on something completely alien to Earth biochemistry.
**Research I've done so far**
I've already done a little bit of research on this. In particular, I've read the [Xenology entry on respiration](http://www.xenology.info/Xeno/10.3.htm). It largely convinced me that gas-breathing beings using an oxidizing chemistry are the way to go. In particular, the entry mentions oxygen, chlorine, and fluorine as possible gaseous oxidizers. I've also read [What's the difference between Oxidation and Reduction](https://www.thoughtco.com/oxidation-vs-reduction-604031) and [Alternative elements for oxygen transport in an alien blood](https://worldbuilding.stackexchange.com/questions/114425/alternative-elements-for-oxygen-transport-in-an-alien-blood). I know there's many more things I could read, but that's a rabbit hole I could spend months going down, only to end up at the same place I started.
I've come here because I'm not confident about my grasp of chemistry, or my grasp of available options for biochemistry models (oxygen/non-oxygen), or my ability to effectively research the right things to learn more without wasting a ton of time and effort. I took chemistry in both high school and university. While I found it interesting and enjoyable, I've forgotten most of it since I don't use it day-to-day. I retain just enough to know that 1) chemistry is really complicated yet extremely well-understood by many people and 2) it's extremely easy to look like a moron when discussing chemistry unless you really know what you are talking about. So I'm concerned about using a gas I'm not particularly familiar with. I worrying about questions like: If a being breathes chlorine, what might they exhale? How would a cabin of their ship need to be constructed so as not to be damaged by constant exposure to both chlorine and the waste product of respiration?
**Questions**
I know I asked some inline questions above. Those can be taken either as flavor questions, or ignored. I think these are the questions whose answers will have the biggest impact on my story:
1. Is my conclusion well-founded? That is, am I plausibly correct that gaseous oxidizing respiration chemistry is the most plausible energy source for complex life?
If not, what else should I consider?
2. The Xenology post mentions oxygen, chlorine, fluorine. Are there other gaseous oxidizers that would be likely to occur in natural biological processes?
other ones that would make sense?
3. If I indeed choose a non-oxygen gaseous oxidizer, what secondary effects should I consider?
For example:
What effect would it have on the
building materials / biology of the races?
if a race breathes chlorine like we breathe oxygen, could their planet of origin have plants?
What materials would they use to construct their dwellings?
Is a photosynthesis-like chemical reaction which produces chlorine or fluorine even possible?
**Closing remarks**
Not all these details will actually make their way into the story, but I'd like to have at least thought through them before I settle on details to include. I don't want to say something ill-considered like "They breathe chlorine" if I don't know what they exhale, or where the chlorine in the atmosphere comes from, or how the ecosystem can stay balanced.
**Information I would find most helpful**
I don't need answers at the level of chemical reaction diagrams, (although if you feel like providing them, that would be amazing!). I'm more interested in knowing potential *"unknown unknowns"* about basic chemistry reactions involving oxidizers. Here's a list of things I just made up as examples of possible *unknown unknowns* that I would want to know about; these are the sorts of things I would want to be told, but wouldn't necessarily know to ask:
* "vertebrates that breathe fluorine would need [x] instead of calcium in their bones because fluorine would dissolve calcium"
* "vertebrates that breathe chlorine would likely exhale [compound Y] because of {the molecular binding energies (or something)}, and plants that metabolize [compound Y] would also need [compound Z] in order to be able to output chlorine again"
* "complex life that respires using chlorine wouldn't breathe pure chlorine. instead, it would need to breathe [chlorine compound] because elemental or molecular chlorine [wouldn't work / wouldn't be present in the atmosphere]"
* A planet with a high fluorine content in its atmosphere would constantly be on fire due to the reactivity of fluorine [unless such and such condition is met].
* etc.
Feel free to answer any subset of my questions if that's easier than answering all of them. I know I'm asking a lot, but I really I don't want to make stupid oversights in my description of alien biology. This is starting as a short story but it might turn into a series if there's interest, and I don't want to have to retcon a basic chemistry error. If a world with a fluorine atmosphere would be constantly on fire, then I'd rather know that *before* writing about it. Thanks!
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I'm going to approach this more as a primer for xenobiology so that you can get the basics down and then figure out just how 'scientific' you want to make your story. There are several aspects to organic chemistry that will help you in setting out your species. I'll discuss them in increasing order of exoticism...
**Chirality**
In Chemistry, any assymetric molecules are considered [Chiral](https://en.wikipedia.org/wiki/Chirality_(chemistry)). DNA is asymetric, and therefore has a chirality whose mirror image is not compatible with it. When you think of organic compounds, creatures of the reverse chirality would have trouble consuming food or other compounds of the reverse chirality (this is discussed in the Mass Effect series, where Turians, Quarians and (I think) Krogan have the opposite chirality to us, and therefore need different food.
Species that are carbon based oxygen breathers but different chirality may well interact with species like us, and can more or less live on the same planets as us, but they can't consume the same food as us and probably would be immune to a lot of our sicknesses (either that or our bacteria could make them VERY sick). In general, they're going to see out other carbon-based planets that already have life with their own chirality if possible.
**Valency**
Why are we called 'carbon-based' life? It's because carbon makes organic compounds possible through an attribute called [Valency](https://en.wikipedia.org/wiki/Valence_(chemistry)), or the count of other elements it can connect to in the creation of a molecule. Carbon has a high valency at 4, which makes all CHNO (Carbon, Hydrogen, Nitrogen, Oxygen) compounds, which we typically call organic compounds, possible.
Some other elements also have high valency. Chromium and Silicone in certain circumstances can have valencies up as high as 6, making them contenders for exotic element based life because of the flexibility in compounding that is afforded by that element.
Such forms of life however will have very little in common with us, and what they call an organic compound and what we call an organic compound will be very different. Such life will have very little reason to interact with us because they can't use our natural resources and we can't use theirs.
**Oxidisation**
You are correct when you talk about chlorine and fluorine as potential organic oxidisers, but as your reading may have already told you, these oxidisers don't play nicely in the sandpit together. Chlorine and Fluorine are both highly toxic to us in any amounts, and some compounds that contain these elements, particularly when combined with oxygen, are very highly dangerous as both combustibles and toxins.
As such, fluorine breathers are likely to find our oxygen rich environments highly toxic, and vice versa. They simply won't come anywhere near planets that we find comfortable and we won't go near theirs. There's no possibility of conflict over strategically placed planets between such species because strategic placement is all about connecting locations of value, and we wouldn't find such toxicity valuable.
**Probability of Incidence**
There's a very good reason why we're carbon-based oxygen breathers; generally speaking (and this is not perfectly accurate) the lower the atomic number of the element, the more abundant it is in the universe. That means that the planets where oxygen *doesn't* exist but fluorine does are going to be very exotic, and very rare. Same with chromium over carbon when discussing valency. That means that there's a very good probability that if we ever come across extra-terrestrial life, it'll be carbon based and oxygen breathing. While more exotic life is *possible* it's much less *probable* than even our existence is, and therefore the chance of it forming into an interstellar travel capable intelligent species is even lower again.
While your exotic life may well exist in your galaxy, it's going to be the exception, and their organic needs in terms of expansion are going to be so different from ours that it's far more likely that both species would leave each other perfectly alone. The only possible trade item that they could share would be information; there's a planet in our space we don't need that might suit you, do you have any oxygen rich planets in your areas? That kind of thing. Other than that, there would be no need to interact beyond academic curiosity.
**Conclusion**
Bottom line is that the more exotic you make life by comparison to ours, the less likely it is to exist at all, and if it does, it's even less likely to have survived to intelligence. Even if it does, it will have less capacity and reason to interact with us the more exotic it becomes due to the fact that there will be less resources we might consume that would be common between us.
To that end, I'd focus on species having different chiralities and the challenges of working together despite this difference. The other species just won't have any reason to interact and wouldn't even respond to each other's distress signals in space because seriously, what are a bunch of fluorine breathers going to even do for oxygen breathers in space? There would be no way to help even if they wanted to.
Species with reversed chirality on the other hand who are carbon based oxygen breathers have a far better chance of working together with us to a common goal (like saving people in space) without competing with us for ALL the same resources, like food.
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I love the aesthetics of retrofuturistic settingsand I aim to build my own.
A mixture of a [fantastical](https://en.wikipedia.org/wiki/Science_fantasy), Thundercats(2011),Outlaw Star x Star\*Drive.
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How yesterday saw tomorrow is quite fascinating to me.
Especially 70s to the early 00s, before the digital and Internet revolutions made the world what it is today.
Those 70s/80s sci-fi works are so interesting because few authors, for all the wonders that they dreamed up, saw the Internet and its impact coming.
Even the small number of works like "The Shockwave Rider" by John Brunner that did envision a Networked future didn't envision it as what we have now.
The world of once current, now retro-scifi, were for the most part conceived of as a better version of the author's present.
Through our modern eyes those older retrofutures seem ridiculous...
* [V.I](https://masseffect.fandom.com/wiki/Virtual_Intelligence) and perhaps full A.I Exist. Yet customer service, manufacture, construction, even warfare, are either done by humans or with automated systems that still require significant human oversight.
* Mobile telecommunication devices, if they exist, operate more like walkies-talkies than modern smartphones or even older cellular phones; they may have video functionality. They're also likely expensive.
* Public telecommunication and information terminals are the norm.
* Personal computers are expensive beyond the average person's ability to buy or nonexistent.
* Electronics are heavy, likely big as well, and work more effectively the
larger they get.
* Physical Media is still very much major a part of society.
* If a computer network exists, it's different from, and more "primitive" than, what we have.
* Computer systems and networks (if they exist) are centralized, around supercomputers/master-control systems. Less powerful systems dial into "Central" to access functions and information that they couldn't perform or hold; [akin to the client-serve model.](https://en.wikipedia.org/wiki/Client%E2%80%93server_model)
* Video game Arcades. Even if video game consoles exist, unlikely, they are under-powered compared to what Arcade machines can do.
I could just handwave all this, have the setting work the way I want through authorial-fiat. But that's not good enough. Even if the audience never knows, I want to have the hows and whys of the setting plotted out.
I refuse have lower standards for the tech of my setting than the magic.
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You have to know the rules before you break them, and I don't know enough about computers, telecommunications, and data storage media.
My setting has its own computers based around weired living crystals.
* The Crystals are basically [artificial brains](https://en.wikipedia.org/wiki/Artificial_brain).
Why the crystals-computers work isn't relevant; what is relevant is their behavior and properties.
What traits must they have for my setting to function like a retrofuturistic one?
* A.I, but limited automation of labor and warfare.
* Public communication and information terminals.
* Limited portable telecommunication.
* Physical Media being alive and well.
* Electronics are big, heavy, and expensive.
The first and only explanation I have is that the crystals-computers actually need to increase in size to increase their performance, and with size comes larger power consumption; Thus the most powerful computers are immobile and have to be tied to a power grid. Which brings back the trope of central/mainframe computer and a master-control.
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The crystals you describe seem to be more similar to a CPU than a complete computer. It makes sense to break down your retro-futuristic computing technology into it's basic parts:
**[CPU](https://en.wikipedia.org/wiki/Central_processing_unit)**: These are crystals that can somehow "think" like a human or - depending on their size - like a super-brain. Of course they should have blinking lights indicating their computing process. Since they are crystals, it seems viable to argue they run on light impulses instead of electric currents.
They should grow very slowly and be brittle to make super computers scarce and "dumb" public terminals omnipresent. If a crystal falls down or isn't cared for and grows bigger than the terminal has room for, it shatters and dies.
**[Mainboard](https://en.wikipedia.org/wiki/Motherboard)**: This is the physical body that connects all components of the computer. It should be a console with physical buttons and maybe some conductive tracks for the general aesthetic. If the CPU crystals run on light instead of electrical power, the conductive tracks could be fibre optics instead of metal. To fit a big CPU crystal with all the conductive tracks it could utilize to compute, the board has to be bigger as well. This makes public terminals limited in usefullness and super computers heavy and stationary.
**[Memory](https://en.wikipedia.org/wiki/Computer_memory)**: The most common computer memories in the 80's were still magnetic tapes or magnetic disks. You could play with this theme by creating miniaturized cartridges with multiple tapes or miniaturizes floppy disks. Memory crystals seem to fit in better, though. Maybe combine both technologies into a (not floppy anymore) crystal disk. These enable people to use personal content and information on public computer terminals.
A super computer needs *a lot* of memory for all it's knowledge, so the mainboard must not only accomodate the big CPU crystal itself, but also connectors for thousands of fibre optic cables connected to racks full of thousands of memory crystals.
**Periphery**: This is all that's needed for the interaction between computers and humans. Terminals are connected by wires or fibre optic cables to communicate with each other. There shouldn't be displays or mouses in the future, instead, there should be a voice module for synthesized speech or a holographic projector displaying the "face" of the computer. The computer gets commands either by being spoken to or by pushing buttons on the console, or both. DOn't forget a slot for a mobile memory crystal.
Since the crystals somehow live and grow, so should their outward presentation via periphery modules. A young crystal employed in a public terminal should have a young voice and face, stereotypically a beautiful female one. An old super computer should have an old voice and face and should be male. You could play with the "wise old lady" theme, but stereotypically the male computer should always be better at calculating and scientific thinking.
**Other stuff**:
Too keep it simple for your readers, I would ignore things like RAM, BIOS and all the interfaces of modern computers. There is no WLAN, USB or BlueTooth, the only data exchange happens vial memory crystals or network connection.
To limit the power of your network connection, you could make it work like analog telephones. The computers are not connected to a giant, all-encompassing internet, but they have to dial each other to communicate. If the line is busy, they have to wait.
**Limit small crystals**:
If a CPU crystal stores it's knowledge on a memory crystal, you could take the memory of a super computer and implant it into a "dumb" computer. But the dumb crystal is much smaller than the super-crystal, so it can only connect to so many memory crystals. You cannot make a small CPU know everything, you have to remove one memory crystal to fit in another one.
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> Physical Media being alive and well.
>
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> Electronics are big, heavy, and expensive.
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>
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Your idea for crystal computers lends well to this aspect of the retro-futuristic aesthetic. You should emphasize that the crystals needed to maintain the quickest, and most powerful computers are heavy, bulky, expensive, and fragile. This would be enough to justify the average person walking around with much less advanced technology—say—a cassette player, or floppy disk.
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Your crystals are **weired.**
They are found objects. Initially on the dark side of the moon, and then on earth. Including places where one would think they would have been found long before now. Were they there all along?
They are semisapient. They are useful and every so often they turn out to be useful for other new things. Useful in ways that one would think someone would have figured out earlier.
It is not clear if they are life forms, things created by other intelligent life, naturally occurring mineral phenomena or something else.
The crystals are connected one to the next but it is not at all clear how they are connected - thus "weired".
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Your story needs to have these crystals but they cannot be the focus of the story. In the course of the action, the reader learns more and more about the crystals - how they were discovered, how they came to be used, how they are integrating themselves further and further into the workings of society, and the apprehensions of some persons as regards the ubiquity and omnipresence of these things, which are not really well understood.
Like the best scifi, your crystals are a metaphor for aspects of the real world which are doing the same thing in our society. Stripped of their name and reality, the crystals are a way to look at that aspect of society without contaminating your exploration with words like "internet".
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As we all know the Earth is flat. Once upon a time a group of explorers set off with the idea of proving that the world was round and that there was a route to the spice islands the other way, but the few survivors came back screaming about seeing ships falling off the edge of the world and something about dragons.
* Some sort of "universal down" keeps everything on the top of the planet.
* Anything underneath falls away (no turtles this time).
* We're not sure how the atmosphere stays in place.
* The Earth's crust varies between 5km (Oceanic) and 50km (Continental) thick.
* The planet runs from Pacific to Atlantic, no Americas, no Antarctic, no Antipodes (sorry Cobbers).
The world's water levels seem to run down slowly but every 12 hours or so they're topped back up again. Nobody knows how this works or where the water comes from, apparently [arrangements are made](https://scifi.stackexchange.com/questions/135286/why-doesnt-the-discworld-run-out-of-water). What this means is that that there's an apparent infinite supply of water and the edge of the world consists of a constant waterfall.
**How long would such a planet continue to exist if subjected to normal erosion from said rimfall?**
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The main problem is that there is bound to be at least one section of the rim that gets eroded slightly faster than its surroundings. This explains the horseshoe shape of Niagara falls.
[](https://i.stack.imgur.com/XQXfG.png)
However if this erosion happens to the rim it will be like breaching a dam. There will be a catastrophic failure at some point and the ocean will drain at that one point. The effect will spread sideways and towards the centre of the planet until the ocean is emptying faster than the mysterious supply of new water can keep up with.
It is difficult to predict when a catastrophic failure will occur but I imagine it would take only hundreds of years. Maybe a few thousand.
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Waterfall erosion happens in two ways:
1. undercutting, where the rock at the base of the waterfall is slowly cut away until the rock above collapse (which can't happen in your scenario).
2. Erosion at the lip of the waterfall where the water going over the edge gradually wears down the rock.
Assuming the rim is of a uniform rock type and starts off just a few meters under sea level (so near 50km thick), it will quickly wear flat. The erosion rate will depend on the force of the water going over the rock, and you have essentially described the pressure of whole oceans bearing down on this rim.
Assuming the water is topped up daily to the same amount, the amount of water going over the edge gets more and more as the rim erodes, exponentially increasing the erosion.
How long the rim lasts depends on it's width, as it will erode quickest at the very edge where the water speeds up, but once it has gone you are going to be left with a river world. This will cause more problems, as all that water is now eroding much smaller areas of crust and will erode through completely very quickly leaving essentially hundreds of bottomless chasms.
Once enough of these bottomless chasms form, you are back to the erosion rates that are more in line with known waterfalls, so the chasms will widen at approximately a km per millennium each (this would vary wildly depending on rock type).
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While the person of the king may go on trips or lead armies in battle, it is another thing to have an itinerant government. In the earliest feudal kingdoms of Europe, the entire apparatus of government moved with the monarchs.
When Charlemagne was the Holy Roman Emperor, he had no official capitol. Many Emperors were crowned at Aachen, but thy were itinerant, moving from city to castle to abbey throughout their realms. Eventually, the Luxembourg emperors stopped traveling, and started to stay put in their capitol of Prague after 1300. The Habsburg dynasty that succeeded them planted their capital in Vienna and stayed until WWII. The Holy Roman Emperors were itinerant until around 1300.
When the Spanish and Aragonese crowns merged with Ferdinand and Isabel, the Catholic monarchs took to an itinerant lifestyle. They moved from town to town, and the court followed. Their great-grandson Phillip II officially set up the capital in Madrid around 1560.
As far as I can tell, this was the last time a proto-nation-state in Europe had an itinerant capital. No modern nation states have itinerant capitals, even those that still have mostly absolute monarchs. Given a nation-state with a development curve typical of one of the nations of Europe, **how late could a nation's government remain itinerant while still developing competitively in Early Modern Europe**?
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## Court and government are two different things
The Royal Court and His Majesty's Government are two very different things, which serve different functions and are made up of very different people; so that, well past the time when this was what was expected of a monarch, the king can choose an itinerant lifestyle if he so pleases, or if he so must.
The times of the stereotypical itinerant monarchs belong to a historical period when there was not much, if any, in the way of central government. Charlemagne could obviously spend all his reign travelling from place to place, because he ruled during the most medieval times of the Middle Ages, when even the notion of a central government was alien to the realms of Western Europe; he simply did not have any kind of government, and the idea that he (or the people immediately around him) would be expected to actually govern the empire did not even cross his mind. The empire was made up of great fiefs, and it was the business of the holders of those fiefs to govern them; the emperor had other business, such as to make war, to hunt, to sire illegitimate children, to make merry, to receive foreign delegations and, time allowing, to attempt to set policy.
But even before the Middle Ages, in the days of the Roman Empire, some emperors choose the life of a perpetual tourist; [Hadrian](https://en.wikipedia.org/wiki/Hadrian) comes to mind: he could be found anywhere in the empire but almost never in Rome. Other emperors *had to* live on the frontiers: for example, Trajan and [Marcus Aurelius](https://en.wikipedia.org/wiki/Marcus_Aurelius). Yet others, such as that famous pervert Tiberius, had a fixed abode outside Rome, and expected to be left in peace unless some important decision had to be made.
Unlike the medieval Carolingian Empire, the Roman Empire actually had a government; but the physical presence of the emperor was not necessary for the operation of the government. They had senators, and quaestors, and praetors, and praepositi, and procuratores and so on to take care of things.
In post-medieval Europe we also find examples of such emperors and kings. Consider the magnificent [Charles V](https://en.wikipedia.org/wiki/Charles_V,_Holy_Roman_Emperor): he was *both* Emperor of Spain and Holy Roman Emperor. Both the Spanish and the Holy Roman empires had governments of sorts, in Madrid and in Vienna, but those governments could, and actually *had to* work without the double emperor holding their hands. Charles V travelled extensively throughout his European realms, as the needs of war and civil and [religious strife](https://en.wikipedia.org/wiki/Diet_of_Augsburg) required. (He did not like it much; at the age of 56, after 40 years of service, he abdicated both crowns and went to o a monastery.)
Or consider the Sun King, [Louis XIV of France](https://en.wikipedia.org/wiki/Louis_XIV_of_France). He and his court were fixed at [Versailles](https://en.wikipedia.org/wiki/Palace_of_Versailles) throughout most of his reign; yet the government of France remained in Paris, and for three decades both parties found this arrangement to be perfectly acceptable.
And even in our up-to-date modern days, I understand that American Presidents tend to be grabbed by an irresistible [wanderlust](https://en.wikipedia.org/wiki/Wanderlust) when elections approach; for example, in October 2018 President Donald Trump of the U.S.A. have no less than [18 speeches](https://en.wikipedia.org/wiki/List_of_post-election_Donald_Trump_rallies) at events all over his huge realm; yet the government of the U.S.A. stayed put in Washington, D.C., and governed the country, and felt no inconvenience.
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I think the breakpoint is when the government reaches a certain level of bureaucracy. Its easy for an absolute king to move court every month or so. It's a lot harder when you've got 10 bureaus and a few thousand people following him.
And as transportation and communication technology improves, you lose a lot of the benefit of having an itinerant king; once you've got railroads, steamships and telegrams it's easy enough to get in contact with the capital no matter where it is.
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My colonizing business found a small planet with about 0.8G. They would like to build the colony in the giant caves under the crust of the planet, due to the conditions of the surface,(little atmosphere, intense radiation, very rocky geography, intense temperatures). Luckily for the colonists, there is some water in the caves. The caves are usually very big, a mile diameter, they slowly get smaller as you get deeper, (completely blocked off at 125 miles). The caves are connected to each other at some point.
So my question is:
**Can they put airlocks on the entrances and keep a working colony with a atmosphere inside?**
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I'm assuming that by "little atmosphere" you mean vacuum or close enough; in which case no, not given entrance ways on the scale you've noted in the comments. The rock into which the locks would be anchoured simply doesn't have the [tensile strength](https://en.wikipedia.org/wiki/Ultimate_tensile_strength) to withstand the structural pressures the lock would exert. The locks are going to be 14 million square feet on an end (assuming 4000x3500ft the door size doesn't change how big the plug needs to be); at one atmosphere internal pressure and an effective vacuum outside they'll exert a total force of 1.3x1011N. Even if the locks are a kilometre deep that's 23400Nm-2, 3.4 PSI, which doesn't sound like much but as an overpressure, which it will effectively be ever time you cycle the lock, it's enough to destroy most modern structures that aren't heavily reinforced. Even if you could build them and use them for a time the [material fatigue](https://en.wikipedia.org/wiki/Fatigue_(material)) of repeated cycles would destroy their anchourages in short order.
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Using Artefaxian's excellent [spreadsheet](https://ruvid.net/video/designing-earth-like-atmospheres-9-j_JOWPLj8.html) I have created a basic idea for my planet, but in the 'Stability Checker' part my low gravity planet is unable to hold *H2O*.
I am wondering if it is possible to have a planet with low gravity and water vapour.
Mars apparently still has water vapour so I think it must be more than just escape velocity affecting the composition of the atmosphere.
**EDIT: I'm wanting a planet with low gravity and oceans, rivers and lakes. Is this feasible or is it only possible to have traces of water on a planet with low gravity?**
[Answer]
The gravity of a body dictates that body escape velocity.
The combination of molecular mass and temperature of the body atmosphere dictates the velocity distribution of the molecules. The lighter the molecule, the faster it can move for the same temperature.
Those molecules having a velocity higher than the escape velocity can leave the body for outer space.
Since the velocity is statistically distributed, you will always have a tail of slow moving molecules, so you will keep traces of any gas (Earth has traces of Helium, though on paper it should not be massive enough for it to happen).
If you lower the temperature you can shift the tail even further, keeping more water vapor with the same gravity.
You can refer to this handy [chart](https://en.wikipedia.org/wiki/Atmospheric_escape)
[](https://i.stack.imgur.com/adFb4.png)
[Answer]
The secret here is the magnetosphere. if you have a planet with a hefty protection against solar winds, a low gravity planet as Mars can retain its water vapor and actually have a working weather cycle.
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Continued from [Can a person covered in mud survive an ordeal with fire breathing dragon?](https://worldbuilding.stackexchange.com/questions/109840/can-a-person-covered-in-mud-survive-an-ordeal-with-fire-breathing-dragon)
Miraculously my protagonist managed to subdue the fire breathing dragon and knock it unconscious. He then tied up the creature which is as big as a double decker bus with a wing span measuring 50 meters from tip to tip. The only thing left to do is to take it back to the village, which is conveniently just across the lake, alive.
Suppose soon there will be a high tide - in the next hour or so. My protagonist wishes to make use of this opportunity to float the dragon and use it as a ferry to reach the other side of the lake. How can my protagonist make sure that his hunting trophy will not drown during high tide? Is there a way to determine the buoyancy of an uncooperative dragon?
This is not a freshwater lake.
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Your biggest problem is the dragon itself: you need to quickly decide if it can float or not, so you don't have time to build a measuring ground to weight it and also measure its volume.
Also chopping out a sample of its flesh to measure its density is going to make it more angry, so it's a no go.
Force its wings open, put some floaters below them and navigate to the other side.
Examples of what you can use as floaters:
* some banana boats
* some conventional boats (this would also provide you with propulsion)
* wood logs (I am sure the battle cut some trees down)
* [...]
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## It will work, probably
* Human body density is between [1.028 and 1.021 g/mL](https://www.quora.com/What-is-the-density-of-the-human-body-What-marginal-change-in-density-is-caused-by-expansion-of-lungs-due-to-breathing), which is just low enough to float in salt water ([1030 g/ml](https://hypertextbook.com/facts/2002/EdwardLaValley.shtml)).
* Horse density is of [0.95 g/ml](https://www.jstage.jst.go.jp/article/jes1990/3/2/3_2_149/_pdf), which would also float.
* Reptiles and other dragon-like creatures [can float sometimes](https://www.youtube.com/watch?v=9TzRLYL8pWg). Think also of crocodiles.
So, your dragon, if built similarly, would also probably float.
## What you can do to be sure
* If you can afford to wait a bit. Put it close to the shore, and when the tide goes up, see if it float. If not, pull it ashore. If yes, everything is fine.
* Attach floating material to it. Wood. Air filled skins/hoses from other animals you hunted.
* My favourite (and it's serious): Feed him with food that cause gases, it will help him float. For instance artichokes, broccoli, leeks or cauliflower.
## Determine density
Otherwise it is very difficult to guess your dragon’s density without putting it in water or in another fluid. Basically, you have two parameters to define density:
* Weight
* Volume
Weight is “easy” to determine, if you have or can build a scale. But the volume is difficult to determine. Usually it is done by putting the object in a fluid and seeing how much fluid is displaced. So, if you are able to build a big bathtub to find the dragon volume, you could as well build a boat to cross the lake.
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To create a map for my setting, I took the following steps:
1. Made a [sketch](https://i.stack.imgur.com/9GO42.jpg) of how the (then peninsula) should roughly look like using the [Inkarate](https://inkarnate.com/) map editor.
2. Took a map of the island of [Hispaniola](https://de.wikipedia.org/wiki/Hispaniola#/media/File:Hispaniola_lrg.jpg), because it had the rough characteristics I wanted: a jagged coastline with many bays, a big massif central and smaller mountain ranges nearby.
3. [Warped and distorted](https://i.stack.imgur.com/uPaeR.jpg) Hispaniola to roughly fit my sketch.
*Note that I dropped the idea of a peninsula here and went with the island.*
4. Retouched the resulting map by using the stamp brush in photoshop to copy a non-distorted texture from the original image to the new map. This resulted in the following:
[](https://i.stack.imgur.com/vUETg.jpg)
My idea behind this process is that deforming an existing topography softly, without cutting or adding/removing features, would preserve the relation between the features of the original map, thus making the new rather believable "per default".
The [reality-check](/questions/tagged/reality-check "show questions tagged 'reality-check'") tag was added because I would like to have feedback on wether the retouched map in its current state would pass as an island that came into existance in a natural way.
For the story, the following parts are crucial:
* The peninsula in the south-east with a hilly landscape (near *Urbo Gracia Granda* on the [sketch](https://i.stack.imgur.com/9GO42.jpg))
* The small island south-east of said peninsula
* The massif central in the middle
* The basin south of the massif central
The basin is supposed have previously contained part of the ocean, but got landlocked in the west, so the water dried out over a long period of time, leaving a salty desert. While I am willing to alter the "salty" part here for reality's sake, I would very much like to have a hot rocky or sandy desert there, or other means of making large tracts of land unsuited for larger settlements (mostly nomads there). I am not concerned with climate or vegetation yet.
# What changes do I need to make to adhere to the rules of general geography?
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**About your map :**
I think it looks pretty good so far.
Just be careful when you add rivers. I would recommend to draw the [drainage basins](https://en.wikipedia.org/wiki/Drainage_basin) (watershed) first.
The limit between watersheds lies along topographical ridges.
Then you draw a river and its affluents inside each watershed.
Rivers should never cross the limits
[](https://i.stack.imgur.com/SNKCa.png)
**About the method :**
I think it works well for small territories like islands. But if you distord continents like Europe or America, people will find out easily .
By the way, the map of Westeros (Game of Thrones) is mostly based on Ireland (upside-down). It becomes pretty obvious when you remove Dorne and the North.
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Scale is going to be really important, "Island" is not a unit of size.
This map is great for something the size of Hawaii or England and relatively poor for something the size of Africa.
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What are the requirements for mass distribution and body positioning that would enable a large creature (say, a panther) to walk on water (and still be able to dive down and swim if it wanted?) This should extend to hunting (chasing fish on the surface and then diving through the water to catch it) to walking to even sleeping on water. The mechanics should be so that there are minimum ripples in the surface of the water, the creature can walk naturally and quietly, and so that the creature can twist itself so it falls into the water. The creature would be held aloft by
* Water tension and mass distribution
* And water magic that would keep the water beneath the paws liquid but tensile, ensuring that the creature could both walk and swim.
And it should be able to walk without any technology or foot covering: just on its bare paws/hooves/etc.
***Update: Thank you for your answers everyone! You were all extremely helpful. I'll use: Big paws, powerful muscles, mass distribution . . . and magic.***
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Basilisk lizards can run across water by pushing water away to oppose the foce of gravity. But you want something that can walk slowly or stand still or sleep. The only nonmagic answer for something the mass of a panther is **buoyancy**. The feet of the animal need to occupy a space such that water displaced by these feet weighs more than the animal does.
[](https://i.stack.imgur.com/rkhTO.jpg)
Zoominbaloons man does not look very panthery but this dude is capable of surprisingly fast movement, or something. So too your panther. It has 4 buoyant inflated feet and it slides around on them like a skater, chasing fish, being awesome.
Inflation status of the feet is under conscious control and the creature can exhale the foot air and dive under. Once it comes up for air it can reinflate the feet and climb back up onto the surface.
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I'm building an alien world for an artistic project. The world circles an m-dwarf star, and so the flora have evolved to photosynthesize longer wavelengths of light than on Earth, primarily in the near infra-red. **I've come up with an interesting symbiotic relationship, however I don't know if its scientifically plausible. Here's how I think it might work...**
Plants have evolved to make use of the near-infrared, with peak photosynthesis at around 1045nm. In my postulated symbiosis, the plant has evolved to feed on the infra-red radiation emitted by small animals in addition to the sunlight. During the day the plant turns its "leaves" outward towards the sun, but at night the leaves curl inward, through holes into a chamber within its "trunk." The chamber has evolved to provide a comfortable and attractive nesting habitat for small animals that in turn not only produce infrared for the plant to photosynthesize, but also disseminate the plants "seeds."
The big questions here...
**Could an organism (the plant) evolve to make use of the the infrared photons a warm-bodied creature produces? And would it be advantageous?** I'm skeptical, since the difference between the near-infrared used from the sunlight on this world (1045nm) and body heat (maybe 10,000nm?) is huge. One order of magnitude. If it could work, how? Would it be through "normal" photosynthesis in which the plant utilizes a larger number of infrared photons to drive the photosynthetic reaction (i.e. many more photons needed for the same energy). Or perhaps the body heat would help the plant drive a completely new chemical reaction that isn't photosynthesis as we know it?
**If the plant can't evolve far enough in that direction, could the animal evolve to produce much higher wavelength radiation, perhaps as a normal by-product of its metabolism?** So perhaps instead of emitting just "body heat" at lets say 10,000nm, maybe it evolves some beneficial or neutral chemical reactions to produce radiation at let's say...2,000nm, which might be a more plausible wavelength for the plant to adapt to utilize. I have zero idea on how that might work. I don't really even fully understand why humans chiefly emit at around 10,000nm, much less what the plausible range of emissions could be as a by-product of metabolic processes.
I'm okay with any ideas from the spitballed to the highly researched. :)
Thanks guys!
***Edit:*** I've been getting some comments on there not being enough energy from the star to fuel complex plant life. This is not the case. The planet I'm working on is close enough to the star to receive more energy than the Earth does, however that energy distribution is strongly titled into the infrared. The planet would seem slightly dim to Earth eyes, but it's far from dark or lacking energy. The salient issue are the really long days/nights (let's say 13 Earth days of night per rotation). I figure there is plenty of opportunity here for plants to evolve other mechanisms for extracting energy from their environment during the many many dark hours.
***Second Edit:*** **Instead of thinking about this problem in terms of light/photons, what if we just consider it in terms of making use of available thermal energy?** The animal is warm, the plant cold, the animal is inside the plant, therefore the plant WILL heat up, creating a thermal gradient from the interior outward. It seems like there could plausibly be some sort of beneficial biological work that could be done with this extra heat energy. Or am I thinking about this all wrong?
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No on both.
Having a plant that can survive on "waste radiation" of an animal would imply the animal is ridiculously inefficient. After all there is this huge fusion furnace in the sky and the animal still counts as a viable radiation source. Such animal would be unlikely to survive and extremely unlikely to evolve naturally. You could of course hand wave some sort of micro fusion or magical energy that animals have but plants do not but that seems non-optimal.
Also note that photon energy is inversely proportional to wavelength. Without going to too much detail this means that converting long wavelength radiation to chemical energy is very hard. Optimally you would want to use radiation where photon energy is very close to the energy of the chemical reaction you want to use and to use fairly energy dense compounds. It is doable with lower photon energies but the needed structures would be larger and more complex and their evolution would be hard to explain.
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## Not via infrared
Chlorophyll absorbs in the 400-700nm range. Anything outside it is not absorbed and is therefore not useful (conventionally speaking). So already at 1000nm you are looking at useless light that most plants cannot absorb. Also bear in mind that absorption is not 100% effective so even if you somehow get energy landing on the leaf that it can use, you are still looking at only about 0.1-2% sunlight-to-biomass efficiency.
<https://en.wikipedia.org/wiki/Photosynthetic_efficiency>
There is some special chlorophyll that can maybe absorb a tiny bity of very high energy infrared but again its no where near your numbers.
<https://www.wired.com/2010/08/infrared-chlorophyl/>
**Edit:**
You also have the problem of as your energy source becomes less and less, the complexity of life it can support also becomes less and less. You're world is more likely to look like a giant sea of algae than a system with trees and wildlife.
Your plant should just eat the little woodland creatures instead if they exist. Or maybe your plant can eat the poop of your little friendly woodland creatures, or eat the leftovers of their meals if they are meat eaters? This might be one symbiosis idea. The creatures bring food into the plant and live there, the plant eats the leftovers? Or maybe your alien squirrels have a lot of parasites and your plant has a nectar that draws those out off the alien squirrels and then proceeds to eat the parasites? Home and pest control, yay!
There are obvious other problems with predicting what life will look like on a low energy planet (probably nothing like earth), but if you need symbiosis for your writing and somehow the world got to the point where there are trees and wildlife, and you WANT them to have symbiosis with wildlife, I think the above ideas probably work.
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I am writing a sci-fi novel in which humanity has colonized a majority of the solar system, and a few minor colonies on nearby stars. Although calculating mass and gravity on individual planets and moons is mostly simple, I am struggling to find out if there is any major difference in gravity based on the moons orientation to the planet. For example, if I am standing on the surface of Titan and Saturn is directly above me, would Titan's gravity be somewhat countered by Saturn's?
Everything I keep finding is the basic equations to calculate gravity on an individual stellar body, but nothing that accounts very well for a counter source of gravity unless it starts getting into General Relativity and Einstein's Field Equation which is way over my head. I imagine in most cases that the difference would be negligible, but I want to account for reality.
**Are there any equations or that might allow me to calculate the difference in gravity on a moon based on lunar orientation?**
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Let's make some assumptions:
* The moon is essentially spherical symmetric, with uniform density.
* There are no other gravitational effects from other celestial bodies.
Denote the position of the center of the planet by Cartesian coordinates $(x\_p,0,0)$ and the position of the center of the moon by $(0,0,0)$, the origin. We can use [spherical coordinates](https://en.wikipedia.org/wiki/Spherical_coordinate_system) ($r,\theta,\phi$) to identify a point on the moon's surface. Since we've assumed that the moon is essentially a sphere, then any point on the moon's surface will always satisfy $r=R$, the radius of the moon.
The distance between a point on the moon (with Cartesian coordinates $(x,y,z)$) and the center of the planet is given by
$$d=\sqrt{(x\_p-x)^2+(0-y)^2+(0-z)^2}=\sqrt{(x\_p-x)^2+y^2+z^2}$$
We can simply use spherical coordinates to expand this:
$$x=r\sin\theta\cos\phi,\quad y=r\sin\theta\sin\phi,\quad z=r\cos\theta$$
$$d=\sqrt{(x\_p-r\sin\theta\cos\phi)^2+r^2\sin^2\theta\cos^2\phi+r^2\cos^2\theta}$$
We then plug $d$ into the classical equation for gravity (and set $r=R$), and we find that the force on a body of mass $m$ due to the planet of mass $m\_p$ is
$$F=G\frac{m\_pm}{(x\_p-r\sin\theta\cos\phi)^2+r^2\sin^2\theta\cos^2\phi+r^2\cos^2\theta}$$
The difference in gravity is most drastic for two objects at [antipodal points](https://en.wikipedia.org/wiki/Antipodes) on the moon. Let's say that one is at $p\_1=(R,0,0)$ and the other is at $p\_2=(-R,0,0)$, where I'm using Cartesian coordinates again. We find that
$$F(p\_1)=G\frac{m\_pm}{(x\_p-R)^2},\quad F(p\_2)=G\frac{m\_pm}{(x\_p+R)^2}$$
Since $R\ll x\_p$ in most situations, we can use the [binomial approximation](https://en.wikipedia.org/wiki/Binomial_approximation). We first rewrite
$$(x\_p\pm R)^{-2}=x\_p^{-2}\left(1\pm\frac{R}{x\_p}\right)^{-2}\approx x\_p^{-2}\left(1\mp2\frac{R}{x\_p}\right)$$
Therefore,
$$F(p\_1)\approx Gm\_pmx\_p^{-2}\left(1+2\frac{R}{x\_p}\right),\quad F(p\_2)\approx Gm\_pmx\_p^{-2}\left(1-2\frac{R}{x\_p}\right)$$
and the ratio is
$$\frac{F(p\_1)}{F(p\_2)}\approx\frac{1+2\frac{R}{x\_p}}{1-2\frac{R}{x\_p}}$$
It should be apparent that this ratio is very close to $1$, but you can plug in some numbers and check, if you want. We've gone through a procedure quite similar to calculating the [tidal acceleration](https://en.wikipedia.org/wiki/Tidal_force).
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It seems that doesn't matter.
Earth gravity varies a bit with geographical location, but you don't have to re-calibrate high-resolution laboratory scales every half hour because the relative position of your lab to the moon has changed.
I'll have to think a bit *why* this is so, because we do have tides, which certainly have something to do with the moons gravity.
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Relating to this question: [Ensuring an endless war, and an endless stalemate](https://worldbuilding.stackexchange.com/questions/83902/ensuring-an-endless-war-and-an-endless-stalemate)
**In a planet such as our Earth, what climate conditions and/or atmospheric changes would be required for the formation and continual existence of the Everboom - a perpetual cloud cover, where there exists a perpetual lightning storm, that covers the entire world, and blocks people from above from reaching below it, and vice versa, without serious protection.**
I'm thinking about a 50 meter thick storm, but if this is too much or too little to come to formation, and to be a serious obstacle for people above and below to cross, I'll change it accordingly - please include this in your answer.
Edit1: People must be able to survive on this Earth, possibly in underground/high altitude floating facilities. So a Venus-like planet might be an interesting example, if it could sustain some breathable, not-melting-the-flesh-off-of-one's-bones atmosphere for the underground caves dwellers.
Unlike the previous question, no magic is allowed here and I'd like to keep technology/intelligent intervention to a minimum - I would prefer this to be a completely natural phenomenon (perhaps with some tech as the catalyst, if needs must).
If this is impossible, extra points if you can point me to something close to it that is feasible (but I don't want to be tagged as an idea generator, so this isn't really part of the question).
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I'm thinking of **continuous big volcanic eruptions.**
Google `year without summer volcano`. Here's a bit of [what happened in 1816](http://www.branchcollective.org/?ps_articles=gillen-darcy-wood-1816-the-year-without-a-summer) when Mt. Tambora erupted:
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> three-year disruption of the global climate system—including a fall in average temperatures between 3°F and 6°F and severe disruptions in seasonal precipitation
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> “An almost perpetual rain confines us principally to the house,” Mary wrote on the first of June from the shores of Lake Geneva. “One night we enjoyed a finer storm than I had ever before beheld. The lake was lit up—the pines on Jura made visible, and all the scene illuminated for an instant, when a pitchy blackness succeeded, and the thunder came in frightful bursts over our heads amid the blackness” (Letters 1:20).
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## [Dirty Thunderstorm](https://en.wikipedia.org/wiki/Dirty_thunderstorm)
[](https://i.stack.imgur.com/mxQYp.jpg)
Electrical discharge can be generated by the ash, rock fragments, ice particles in a [volcanic plum](https://en.wikipedia.org/wiki/Volcanic_plume)e (a column of hot volcanic ash and gas emitted into the atmosphere during an explosive volcanic eruption).
Combine this with the water vapor caused by the incessant volcanic eruptions, you'll get [Earth in its early stage](http://volcano.oregonstate.edu/origin-atmosphere).
Actually, this might be when your story start; history before mankind: Elves and Dwarves. Although this `Everboom` will slowly dissipate as the earth become more mature.
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Look at the closest example of a rocky planet with perpetual cloud cover: Venus.
It is constantly covered by clouds, it has flabbergastingly strong winds and also a huge greenhouse effect. This, on top with sulfuric acid in the atmosphere, makes life on the planet impossible.
Since you want to have life on your planet, you are pretty much out of option if you stitch to visible light. If you make your living beings able to see in the infrared, they could experience a thick cloud cover while in the visible spectrum the sky would be just foggy.
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I understand that there is an on-line site, named Impact Earth!, that allows us to calculate the damage caused by an impact of an asteroid using some parameters.
In my novel, I have an impact from a solid rock with approximately 500 meters in diameter on the ocean bed, free falling at a 90º angle.
Trouble is, the calculator only allows for a minimum velocity at impact of 11 Km/sec since that is the lowest speed an asteroid may hit the Earth.
But my solid rock isn't an asteroid, but rather [one of these airborne islands, floating 1.500-2.000 meters above ground](https://worldbuilding.stackexchange.com/questions/68902/naturally-ocurring-airborne-floating-islands-is-it-possible). The initial velocity would be 0, so, according to my calculations, it would hit the surface of the sea at a velocity of 170-190 m/sec, much lower than the minimum velocity of 11 Km/sec allowed by Impact Eart!
Could anyone help me with these calculations?... I am interested mainly on the height of the tsunami waves and on any atmospheric changes that would be visible (if any).
Note: I have yet to decide on the ocean depth and the distance from the coast at the site of impact... I would like the impact to be relatively near the shore, maybe some 3 to 5 Km away from the beach.
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Let's think about the volume of water displaced by the island: your 500-metre floating rock has a volume of $\pi r^2 h\approx 40\times10^6\ m^3$. (I'm guessing a thickness of 50m)
Now lets model a tsunami as a wall of water, in a ring, 500m wide with a height of h. At a radius of 5km, the volume of this ring would be $h\pi(5000^2 - 4500^2)=40\times10^6$. Giving a value for h of about 40cm. Now tsunami grow in size when they reach land, you can, therefore, expect a significant amount of wave action.
Taking the value $E\sim 10^{14} J$ from the comments, and using <http://alabamaquake.com/energy.html#/> to convert this to an Earthquake, gives your island hitting with the equivalent energy of a 6.5 magnitude quake. That would be a potential minor tsunami, of about 10cm However all the energy of the impact is converted to wave energy. so we can expect a larger tsunami that would be predicted for a 6.5 magnitude quake: consistent with the 40cm tsunami calculated by considering displacement.
All this points to a potential significant tsunami of several metres when the wave has been compressed in shallow shore waters, but not a catastrophic wave of 10s of metres.
The "splash" would be impressive, but I don't think that there would be atmospheric effects. It would be loud, but not "Krakatoa" loud
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You can proceed along this path:
1. Estimate the kinetic energy of the "rock" when it impact the ground/sea with velocity v. This is $$E = 1/2 mv^2$$
2. Calculate the equivalent amount of TNT which, exploding, deliver the same amopunt of energy. Use as reference $$1kton = 4.18 TJ$$
3. Use some reference explosion to have an hint of the damages:
* Typical airborne bomb= 0,00025 kton
* Halifax Harbor explosion (6th Dec. 1917)= 3 kton
* Nagasaki atomic bomb = 10 - 30 kton
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Looking at a race based on Hobbits or Halflings, and I am wondering about the average weight and if that is affected by denser muscle mass (than human children of the same height), and the realism of their strength.
Using D&D as my guide, but it seems...high for something that's supposed to weigh only 30 pounds and be 3 feet tall.
At Max strength a light load for a halfling is supposed to be: 57 lb. or less, which is almost x2 their body weight. Light load means they are not encumbered by the weight. Medium is 58-114.75 lb. Heavy is 115-172 lb. Heavy means that you're encumbered significantly but you can manage it.Keep in mind, this is the max ability, so these would be the equivalent of, say, a body builder.
Average strength is 24.5 light load. 25-49.5 Medium & 50-75 Heavy. The light load is such a high number for this, when they only weigh 30 pounds, that I am balking at this being realistic.
**Is this strength scale and capacity realistic for a 30 pound, 3ft tall humanoid that isn't child? What would be more realistic if it is not?**
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In DnD, carrying capacity is multiplied by a factor related to the size of the creature. The numbers are:
**Small ×¾, Tiny ×½, Diminutive ×¼, Fine ×1/8**
The standard numbers on the carrying capacity table are meant for medium (normal human) sized bipedal creatures, for a small creature such as a halfling you have to multiply every number by a factor of .75.
Well, this means that your so called 57 lb max is really only 42.5 lbs, which is just over their own body weight. Seeing as most people can do bodyweight exercises, this seems just fine.
You also didn't mention what the strength number you're using is, so I'll assume that you used 14 strength as the base value. However, in DnD, you can roll stats for commoners, which is 3d6 worth of rolls.
It turns out that with 3d6 rolls, about half the people will have scores between 3 and 10. Since we're talking an average person (not a leveled up PC), we should use an average number to determine the max values, not 14 (which is really high).
If we use 9 as the Strength value, then the max value for a normal humanoid is **30 (light), 60 (medium), and 90 (heavy)**, meaning that for a halfling, the max is **22.5 (light), 45 (medium), and 67.5 (heavy)**.
Do these numbers make sense? I think they do - the light load for a 3 foot tall human that isn't a child and is probably way more beefed up than a child is around the weight of one dumb bell, which sounds right to me.
Note: I'm assuming that 9 strength would be an average body builder's strength IRL based on deadlift capacity. I don't work out and I can deadlift double my bodyweight properly as a max lift, so for a halfling the numbers seem fine.
Note: DnD 3.5 numbers applied in this answer. Other versioning values may vary.
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D&D seems to neglect the relationship between linear dimensions, surface area and volume, and this has consequences that occasionally make the relationship of strength and size in its RAW unrealistic.
For a solid of a given shape, increasing scaling its linear dimensions equally so that its height x1 becomes x2, then the increase in mass is proportional to (x2-x1)^3, and the increase in its surface area is proportional to (x2-x1)^2. this works both ways. This also means that the bigger an animal becomes, the thicker its bones need to be, proportionally to ((x2-x1)^(3/2)).
If we consider a human to be (on average) 180cm (6') tall and 75kg (165lb) in weight, then a Halfling 90cm (3') tall ought to weigh 75\*(0.5^3) = 9.3kg (20lb).
If we also consider that an average adult male human can lift around twice his body weight, or 150kg (330 lb), then a Halfling of similar proportions should be able to lift 150\*(0.5^(3/2)) = 53kg (116lb), or *over five times his own body weight*.
Since halflings are derived from Tolkien's hobbits, which are not described as being especially slender or childlike, but have an appearance similar to that of a human, then this is not an unreasonable conclusion.
Carrying this even further, a 5cm tall fairy with similar proportions to an adult male human's should weigh 1.6g (0.003lb), and should be able to lift 694g (1.5lb), which is *433 times* their own body weight. This sort of strength is sufficient to make them able to wrestle mice and possibly even rats (up to about 500g) that outweigh them by an enormous factor into submission, since most small animals are also proportionally more slender. Consider a 5cm long grasshopper - its legs (other than its hind legs) look twiglike in comparison to a human scaled down to a similar size. A human-proportioned creature of that size would be a literal superman.
So, to answer the question, 30lb is way over the weight that a human of that size ought to be, by a factor of 50% (maybe these are very fat halflings when compared to humans), but 75lb wouldn't be unrealistic as a heavy load for extended carrying when the maximum weight that such a being ought to be able to lift for brief periods is 116lb.
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This is D&D, not reality. So, no, it is not remotely realistic.
Strength is due mostly to muscle mass and leverage. A 30-pound halfling simply doesn't have that much muscle, particularly after you account for bones, skin (the largest organ of the human body) and entrails. Furthermore, without significant increases in joint size you wont get the leverage needed.
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Assume we have a sentient race that is both non-dimorphic insofar as males and females have no non-cosmetic secondary sexual traits, simply different reproductive organs and perhaps different cosmetic features, and *oviparous*, i.e. laying already-internally-fertilized eggs. (For instance, this is one possible way to implement reptilian sentients or dragonkin reproduction-wise.)
How would gender roles be divided up by such a people, considering that:
* The egg only stays resident within the mother for a short period of time (hours?) after fertilization (i.e. spend a night in bed, lay the egg in the morning)
* Eggs are fertilized/laid one at a time -- if you want another egg, you have to have another go at it with your spouse
* Neither parent is any better equipped to care for the egg than the other
* Incubation of the egg does not require brooding (the egg can be hidden in a suitable spot and left there)
* Young do need at least some care after hatching, but this also can be provided by either parent
* There is an even chance of getting either gender from any given mating, and it's not influenceable by incubation conditions
Would we see a lean towards one gender or the other handling parenting, or would it be a dead split down the middle? How would the risks for having an even gender split in combat be different? Would we see concepts like patriarchy or matriarchy?
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I think there would be some differences, but they'd all be based on the fact that only females can lay eggs, which makes them the childbearing sex, like always. Any species, whether offspring are brought to term through egglaying or developing inside the mother's body, can only afford to lose so many healthy, fertile females without extinction. In essence, they'd probably be pretty much like us but with more gender equality since due to lack of dimorphism, females wouldn't be the "weaker" sex.
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Another factor that should be taken into consideration is the amount of investment required in order to successfully rear the child to adulthood.
If the amount of effort is intense and lasts for more than a decade, the pattern of something like the arrangements we see in humanity will emerge.
If the investment is brief or light, then the mother will do the bulk of the work.
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(New here!)
As I am setting up the astronomic framework of my new world, I have real issues finding information, formulas and calculators to get the actual size (diameter or radius) or apparent size (disk size) of my moons.
I know my roche limit and the hill sphere of my planet, and I have 3 placed moons in given distances from my planet and their orbital period, but how do I go on with actual size and apparent size of a moon? Doesn't that depend on mass too?
I need to know how big my moons must be, for example so that one of them covers the sun disk for an eclipse with a corona, and for other reasons.
**Any known links to calculators or formulas regarding this topic?**
For completion, these are my moon datas at the moment, the planet is roughly like earth (1 earth mass, 0.9 radius):
Moon 1 - distance: 19.110 km, orbital period: 7.27 hours
Moon 2 - distance: 171.990 km, orbital period: 196.4 hours
Moon 3 - distance: 509.000 km, orbital period: 1001.76 hours
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This is really just [basic trigonometry](https://en.wikipedia.org/wiki/Angular_diameter).
```
radius / distance = tan(angle / 2)
```
or rearanged for diameter:
```
diameter = distance * tan(angle / 2) * 2
```
For example: When you want your moon 1 to fill 0.5° of the sky (about as large as our moon), it needs to have a diameter of `19110km * tan(0.5 / 2) * 2 =` 166 km.
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**Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers.
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**Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/55530/edit).
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[Improve this question](/posts/55530/edit)
When speaking about other universes people usually consider altered physical laws, while leaving logic and other basic things unchanged.
What if to consider other universes based not on different physics? Particularly, define a universe as a flow of qualia, thus considering universes with different flows of qualia? I think this expands the range of possible universes a lot.
Example: when you are sleeping you feel like living in a different universe, but that universe has no physical laws and totally different logic. Yet it generates a flow of qualia so can be considered quite an example of a universe (if it were not followed with awakening).
Other examples:
* Universe where everything the observer believes true is true.
* Universe where everything the observer wants happens.
* Universe where everything the observer fears happens (consider here Warhammer universe with its Chaos zone).
* Universe where everything the observer imagines happens (quite close to the world described in "The Chronicles of Amber" by Roger Zelazny)
* Universe where there are only different smells and no space, form or geometry.
etc.
I think the sleeping dream universe is quite a strong case because it changes not only perceptive qualia but also reasoning qualia, altering the whole process of thinking.
Of course, if we define universe as a flow of qualia, the observer is necessary in every universe and he is unique in each universe.
What can be other possible universes based on qualia-based definition?
I also wonder whether the above examples are uncontroversial. Can a universe where everything the observer wants or believes exist? Can it lead to paradoxes?
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You are attempting to answer the thought experiment, "[If a tree falls in a forest and no one is around to hear it, does it make a sound?](https://en.wikipedia.org/wiki/If_a_tree_falls_in_a_forest)" Wikipedia, as linked, has a pretty in-depth view of the philosophical takes on the matter.
Important to your question is the concept of 'unperceived existence'. While I can't speak for you, my life has certainly taught me that my perception of things is not the same as the truth. I am wrong all the time, and I can't understand why, because I could swear that I experienced something a certain way but it turns out something else actually happened. In the universe you are proposing, your personal experience is an equally valid reality to what actually happened in the 'real' world..if it even happened since you need someone to experience it for it to become part of a universe.
This leads to another concept: how can your reality be 'real' if there is no way to share it? If each person's qualia are their own universe, and nothing is real unless experienced, then since your qualia can't be identical to someone else's you can't exist in the same universe as them.
What I argue for, in this case, is that qualia cannot define its own separate universe, because it cannot be communicated to anyone else in its entirety. Even the very mode of communication (writing, speech, ESP) will alter the experience of the second-hand receiver of experiences. If there is no way to pass on information about this universe, because the act of passing this information creates another universe, then the original universe isn't a useful concept. There has to be a shared 'tether', a shared set of facts that everyone can agree on that people can use to communicate to each other, something like a language, shared experience (not personal experience, like qualia), or something.
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In this explanation every person inhabits his or her own universe distinct from all others. What's more, each person experiences multiple universes and they change all the time. When they're sleeping, drunk, traveling, changing careers or friend groups.
This is interesting to think about up to a point, but what of reality? That thing which still exists when you stop paying attention to it? Everything else is hallucination, imagination or dreaming.
The question is: are any of these hypothetical universes actually real. Meaning, can multiple people experience them, can independent experiences of the universe be lined up and compared to find common ground? Can a new person show up and experience a similar thing?
If one of your odd universes was actually real and other people could reliably (or even unreliably) share it, that could be very interesting.
Philip K Dick explores these questions at great detail. In fact that might be what he was all about. Eye In The Sky explores the universe of desires. Several novels posit alternate shared realities accessible through hallucinogenic drugs. Several other novels posit that it's possible to experience a life skipping between universes. He once said "Please take my word on it that I am not joking; this is very serious... often people claim to remember past lives; I claim to remember a different, very different, present life."
What other universes are possible?
All of them. Everything anyone can imagine and then some.
More importantly though, which of these possible universes can be shared? I'm not sure, but please think deeply on this and then write about it and maybe in a small way I can share something of the universe you create.
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I'm building up a world with floating islands. They don't move much and generally stay around the same area. However, would this affect the weather?
Essentially, I have giant floating rocks in the atmosphere(similar to earth) which will not go higher than 14 km above sea level. The mechanics behind the floating islands do not affect anything other than the islands themselves whatever they might be. The islands can range from the average size of a family car to about 500 sq meters.
Some of the islands can clump to gather to form 'super' islands and there are on average about 50-100 individual islands every mile or so.
I can't solve the problem with wind erosion so negate it for the moment and assume that someone(me) performs maintenance now and then.
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Given the back-and-forth in comments & your edits, I don't see any global weather issues. If many of the floating islands are low in the atmosphere (tree-top level), you'll have issues of erosion on the surface where all the rain from a 500 square meter surface drizzles down in a sheet around the island, but if they're higher than that the sheets of water will disperse.
The only effect I can see locally deals with snowmelt. Snow would stay stuck to the top of the mountains, and would melt off and fall as rain, instead of melting more gently into the water table. More erosion, more flooding during the thaw, and some artesian aquifers wouldn't be recharged as well - which means fewer springs.
If the material of the floating rocks is generally the same as the surface (same rocks/soil, same amount of vegetation), then it shouldn't affect the planetary albedo - but if the rocks are all mirror-surfaced or dark black, then you'd see a change on the order of 1 part per thousand in the albedo. Enough to shift growing regions north or south, but it's a fantasy world and you can just specify that stuff by fiat (ie adjust the sun & the atmosphere to compensate).
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Depending on the height of the floating landmass they may not receive much rain. Rain clouds (stratus) are at 6,500 ft (1.98 km) or lower. Landmasses above this may not receive much rain, and any lower than 2 km would block portions of the earth from receiving rain beneath their floating mass.
However thunderheads (cumulonimbus) can reach up to 50,000 ft (15.24 km) and have hail, lightning, and torrential rain. So with this type of cloud it is fully possible for higher floating islands to receive heavy rain and other intense weather conditions.
Floating islands present a different condition than mountains which have a base and cause air to go up cool and lose its moisture. With no base the islands won't catch as much air (and their shape may not be conducive in making air rise) so most weather should be natural and unaffected by the floating islands, ie carried by the wind. Especially the smaller islands, if they range from `average size of a family car`, then you can compare them to hot air balloons or planes which are bigger than a car and don't affect the weather at all.
Something else to keep in mind is the freezing level, about 2 degrees C per 1000 ft (.31 km). So if on the surface its 75 deg F (23 deg C) the freezing level is about 11,500 ft (3.5 km). Any floating island above this height will most likely not have rain but snow and ice.
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A floating island would only affect local immediate weather conditions, mostly underneath. Cooling underneath, light sensitive things affected, spillover from the island impacting the terrain, etc..
You would need to get up in size to begin affecting weather globallyl. The island shadow will change growing conditions underneath, with the impact increasing over time. Sufficient surface area coverage would alter the wind streams (currents if over the ocean) which form the weather patterns, and affect evaporation. In a dry environment, blocking the light might result in a desert underneath, but in a moist environment might result in endless field of mold and decay, or field of snow.
Not to mention being an easy way to throw rocks.
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In my fictitious universe, a god like entity ( which is an amalgam of all individuals , scientific understanding , capabilities , and tech of a type 3.5 civilization ) produces a sun with the same mass of our own , and a habitable Dyson sphere around it.
My question is : What movement or mechanism would be necessary to cause shifts in seasons inside of such a Dyson sphere?
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Your Dyson needs to move around the sun the same way a hula-hoop does around the person spinning it around their waist. If this happens then some parts of your sphere will be closer of further from the sun than others, and "seasons" (changes in temperatures) will occur.
The radius of this "sphere" will need to be slightly bigger than 1 AU, thus making the diameter slightly bigger than 2 AU, which will allow movement without bringing one part of the sphere so close to the Sun that it fries.
The exact size would be based on how far away the Earth ever gets from our own Sun.
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Axial tilt is the reason we have seasons on Earth however you would not necessarily want to do that. Look at it this way. The only thing you would get out of it would be your seasons. I would put an inner sphere in my Dyson Sphere and cover it with a solar film that I could adjust over whatever areas I wanted to give me both power and whatever seasons I wanted. Just think what kind of political fallout you could create over control of the film. You could control who was a first world or third world country and furthermore everyone would be always fighting wars for control of the film! What fun!
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Niven's original RingWorld (which is somewhat similar to a Dyson Sphere) had an inner ring containing sunlight blocking plates which cast shadows upon the inhabited surface to simulate day and night. In his novel, the spaces in between the plates were empty and allowed full daylight to shine through, but there is no reason that these empty spaces couldn't be semi-transparent and varied so that different amounts of sunlight gets to the surface at different times of its "Year".
Also, since you are going for a sphere, the thickness of the atmosphere contribute to seasonality. The air will be thickest along the equator relative to the sphere's rotation and thinnest near the axis upon which it spins. If the upper parts of this atmosphere was composed of light-absorbing gases, there might be a relatively permanent seasonal distribution of temperatures between the equator and the axis, with the average temperature climbing higher as you traveled towards either axis. Not an annual schedule of changing seasons but a differentiation of climates across the available land mass.
Now add a few super oceans into the mix in the higher realms where the air is thin and the sunlight hottest and you could create some enormous storm systems, rotating moisture down towards the equator and simulating seasons, not from the distance from heat/light source (which would be constant), but using super-dense cloud cover instead.
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A rigid completely enclosed Dyson with 1g internal-face gravitational acceleration build at a radius of around 1 AU (thus requiring magic-like technology) would be incredibly bright, with an temperature following the formula:
$T=[E/(4 \pi \eta \sigma r^2)]^{(1/4)}$
where $\eta$ is the emissivity (=1 for a blackbody), $\sigma$ the constant of Stefan-Boltzmann's law ($5.67032e-8 Wm^2K^{-4}$)and E the total energy output of the star measured in watts.
**All** the energy of the sun hits the Dyson, which has an Earth-like albedo of 0.37. It's gonna be hot.
Earth is cooled by its rotation, reducing the flux in half effectively, and by its spherical shape resulting in light hitting it as shallow angles. The Dyson does not have this features.
A back of the envelope Wolfram Alpha calculation suggests that at about 1AU with a sunlike star, the sphere would have an equilibrium temperature of about 400 K.
Not sure about seasons, but you can easily boil eggs. Or people.
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Time period is renaissance, with the most powerful culture being in a area geographically similar to the middle east. So a cleric was trying to combat a drought in his kingdom using the power of a solar eclipse, he invoked great divine energies to accomplish this. However he went *a bit overboard with his wish*, he said that "It shall rain from the heavens, such is it does during the best of times, and mana able to sustain all plants and animals, shall rain from the heavens with it.", suffice to say this didn't turn out the way he was probably hoping.
The interpretation his wish wasn't quite so bad as it theoretically could have been (it could have ended up raining mana and water 24/7 for one), however it still turned out that following his instructions, the wish *didn't really go so well*.
In addition the spell somehow ended up effecting 6 areas instead of just his own kingdom: The areas affected were a 260 mile area around his capital which is a city comparable to Baghdad in the ancient world but more powerful, and a 130 mile area of 5 other places. One area is on the the continent directly opposite the earth in an area similar to Kansas which is moderately populated and akin to medieval era Europe. Two other areas to 90 degrees of those 2, one just being open ocean akin to the middle of the pacific, and the other being part of an island chain akin to the Philippines with Aztec level civilization. The last two are to 90 degrees same as before but are arctic, one is in a area of arctic ocean, and the other is on a continent to the north similar to Antarctica. Together the 6 locations align perfectly as each is on its own face of a cube of mystic ley-line energy. Magic is assumed to be rare enough it shouldn't affect your answers, no the effects aren't likely to be reversible for at least a millennia.
**The actual effects**: the spell sets precipitation equal to the average precipitation during the rainiest quarter of the year, this goes based on averages over the past few millennia. More devastating however is that whenever it rains it also rains "mana".
Mana is a substance designed to contain the necessary nutrients to nourish any plant or animal in the areas affected, this is based on life in all affected areas at the start of the spell. The resulting mixture is very sugary (to sustain hummingbirds and some insects), rich in many different nutrients and proteins, and is also rich in nitrates for plants (though with the exception of algae most would actually not respond well to such high amounts), by trying to provide the optimal nutrients for every plant and animal it ended up providing too many for the vast majority of them.
The mana falls as syrupy rain (may freeze in arctic but is nearly all sugar, plus fats, proteins, etc so it will freeze at much lower temp). The amount that falls is about equal to the amount of water rain caused by the spells effect, and as mentioned before, precipitates along with it. In case anyone's thinking about how this would increase the earth's mass over large timescales it won't, the extra rain is pulled from the oceans and the nutrients are assembled from material pulled out of the crust.
***Composition of mana and amount of rainfall and manafall, is set once the spell starts and will never stop or change in any way.***
***The question is,*** this would probably be pretty bad, but just how bad? How would this affect the environment in the areas directly altered by the spell, and how far will the effects reach beyond that? How will it alter the societies in and around the areas with manafall? Not looking for answers over timescales of millennia, how life would evolve with such massive nutrient infusion will be addressed in a later question.
Some really obvious implications; I imagine that this will cause massive algae blooms in any water source, and will likely kill many plants due to too many nitrates. The sticky syrup will be a great food source for insects, but it will also get many of them trapped in its sticky syrup so I can't say what the net effect will be. *I can't really predict what the effects will be beyond that*(thus why I ask the question), though I highly suspect that the affected areas will *reek* from all the bacteria that it will cause to explode in number.
I suspect the areas affected will be bad enough that it will cause mass emigration. The mana may also cause the surrounding areas to flourish however, since it can be added to other food to sustain people (by itself it may cause hypervitaminosis, and is unappetizing as a gross syrup), thus allowing a food surplus.
This question's answers, will likely be applicable to many potential scenarios where an area has a large overabundance of nutrients suddenly introduced.
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Picture a large grass meadow with an area of about 200 million square miles.
Within this grassland you have 6 locations of extremely high nutrients. However, the combined area of all these locations is less than 0.0024% of the total area.
Picture a normal cow pasture. Grass will be fairly evenly spread, but you will see some areas with a ring of taller, greener grass surrounding much shorter and yellower (or even dead) grass. This is the spot where a cow flop (ie poop) landed. The immediate area has too much nutrients and hurts the grass. The ring is the area that gets extra nutrients, but not too much. Out beyond that, life continues as normal.
Your civilizations would have to migrate away from the poisonous amount of nutrition, but could eventually adapt.
The areas in the oceans are likely to be oxygen dead zones, as the algae blooms use it all up. Down current of these locations, as oxygen mixes back in, animal populations will explode from the massive availability of nutrients.
The (2?) areas on land will have very fertile belts surrounding these mana-zones. Population will migrate to that area, both from the mana-zone, and from other, less fertile, areas.
The "antarctic" zone will have its semi-frozen sludge slowly ooze its way into the ocean, where it will likely also cause a dead zone near the coast.
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I'd like to send my protagonist permanently into the near-ish future. I suspect that something as simple as the common cold could be deadly to my protagonist once we get a little further along.
I am looking for a rule of thumb that there might be, in science or hard science-fiction. Setting aside the following variables:
* Yes, I know everyone's body is different, I haven't been sick for more than a decade while I have friends who are sick every month. I'm just looking for a rule of thumb.
* Yes, it's fine if there's been an advance in medicine, but this is about contraction (and, if there's a rule of thumb used in fiction) of common airborne diseases as we know them today, such as the cold. Assume our daily, urban lives are as they are in the West, just with near-future technological advancement.
* My protagonist came from today and I want her to travel as far into near-future (100 to 200 years) in the same, progressing country, that wouldn't create a quick contraction of a virus or bacteria that could cause major complications.
To avoid this from being too broad: **What's the best rule of thumb in worldbuilding/storytelling or historical precedent for how far a person today might travel without being seriously compromised by a common, airborne disease; without imagining completely new diseases.**
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You can get a stinking cold just by being projected to next year.
As a general rule, your traveler from the past is going to be taking long cured/vaccinated diseases to the future rather than getting new ones by traveling to the future.
That wouldn't have been true during the great age of exploration through the 15th to 19th centuries mind you. During that period the western explorers were picking up all sorts of fascinating new diseases from across the world.
In terms of colds, people tend to have a localised immunity. As people travel across the world (especially freshers at University) they take a home version with them and spread it around while picking up a local version at the college.
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Imagine if you will, a traveler from 300 years ago landing in our time. (I know this is a greater time than you're looking at but it's a good point in history for this.) This person is going to turn up with a few virus variants that we haven't seen for a while and will catch a few from us, but he could turn up with any of TB, Bubonic Plague or even Smallpox! To us these diseases are largely consigned to history or standard vaccination and treatment schemes but to them they were a part of life.
What would your traveler be taking with him that the people of the future have consigned to history? Measles? Chicken pox? Polio? Things that should have been forgotten are now showing up because he traveled to the future.
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In a world where every human being can fight using their minds, every person effectively has a ranged weapon on them at all times.
Societal change in my setting has brought about a major decrease in street crimes and an overhaul of the world's prison systems, but law enforcement would still need to detain dangerous people. You obviously can't just cuff someone, nor can you just throw them in a normal cell where they could attack other prisoners or even the guards.
How would prison infrastructure and detainment procedure need to change in order to prevent prisoners from posing a constant threat?
More info about mental combat:
* This ability is technological and probably *should* use electromagnetic waves, but in this setting there is no known way to block the signal that initiates combat.
* The attacks have a range of no more than a few kilometers.
* Attacks can be initiated on only one person at a time, and the attacker must be aware of the person, in the sense that they must be sure the target is in a general area.
* Attacks *can* be made against someone you can't see if you can visualize where they are. You do not have to know who this person is or what they look like.
* There is no penalty for being wrong about where a person is. As noted above though, the attacker must be convinced that someone is there. No random guesses.
* Attacks are not detectable by other parties. You will only know when one of the two combatants tells you afterwards or passes out.
* Attacks are traceable using a unique identifier. It is trivial to compare a suspect's id to the id found in a log file.
* Mental combat happens at a greatly increased timescale. Combat is usually over within a second, though it seems much longer to those involved. Being the initiator does not convey significant benefits.
* Your mental state influences your skill in combat. If you are drugged or otherwise incapacitated, you might still be able to initiate combat, but you probably won't win.
[Answer]
**Remote controlled combat robots and prison architecture.**
We'd have to change to the usage of electronics.
Robust robotics and engineering would have to be utilised to both control the flow of movement of detainees and inmates, and also detain them in the first place.
Remote-controlled bots, so to speak, similar to the one utilised by the warden in the episode ["Gravity Jailbreak"](http://www.imdb.com/title/tt0964371/) in the television show Outlaw Star. In it, the prison's main feature is that the gravity is very powerful, so the way the warden controls all of the inmates is that he controls a robot remotely so he can manage them directly while they remain at a disadvantage.
The premise here is the same - you can't render a robot unconscious unless this ability directly interferes with electronics. As your question is stated presently, you have not forbidden this, so I believe it to be an excellent solution. All criminals/prisoners would constantly be trying to use their ability but they can't so they remain at a disadvantage to the mechanical strength of robotics.
You set everything remote like the one I outlined here: [Being the Warden to the Correctional Prison Planet called Slearth, What types of rules would you regulate?](https://worldbuilding.stackexchange.com/questions/32830/being-the-warden-to-the-correctional-prison-planet-called-slearth-what-types-of/32835#32835)
Combine this specific architecture/protocol with the ability to combat and detain criminals, and you're golden. You only have to make sure that the person controlling the robot is not visible.
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**Drug them.**
Clearly, they need to be kept in a state where they're not able to harm people. So, keep the prison out of range from outsiders, do not let the prisoners see the inside of the prison, keep them blindfolded or in the dark, and **drug them into a stupor** for the duration of their sentence.
It may seem cruel by our standards, but you're simply restraining their freedom to move and use weapons. The solitary nature and drug-confused state will make the sentences particularly undesirable, which can mean shorter prison terms and a better overall deterrent.
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Well all prisoners could be forced to wear one of these.
[](https://i.stack.imgur.com/AeOH0.jpg)
However since it uses technology, then it should be fairly easy to interrupt the mode of communication needed to work. All cells will be equipped with white noise generators (or static) for the E-M bands (instead of actual noise). That cover the full spectrum of the communications band.
Sensors would be used to monitor any communications going into or out of the prison, looking for signals that might get through. Since someone is in jail, there is a very good chance that someone outside wants to do them harm as well.
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You need to eliminate the components necessary for successful offensive attacking. To attack effectively, the person must be able to target someone, initiate a fight with them, and then win.
**Eliminating the ability to target**
Either remove the human aspect by replacing it with computerized programs or droids, or remove their ability to sense others. Since they can't guess randomly, removing their ability to hear or see prevents them from accurately determining a person's location. For imprisoning them, just extended slots or machines for depositing items to them, such as food, so they can't tell where the person is exactly.
**Eliminating ability to attack**
Have someone attack him first. Since the fight seems to be dependent on strength rather than who initiates, if you have someone stronger attack first, then you gain control over him and render him incapable of attacking. You state that they can be *"initiated on only one person at a time"*, so attacking first with a designated person should render them incapable of attacking anyone else. This will be useful when you need to move or transport the captive, especially since you should be able to target him at will but not vice versa.
Or drug them, but that's included below as well.
**Eliminating the ability to win**
This is the easiest one. Prevent them from being able to attack at all by knocking them out using either force, drugs, or some other agent. Getting to them may be more of an issue, but there are far too many possibilities to discuss there. When imprisoned, add drugs to their food to ensure their mental capabilities are limited. You can also induce sleep deprivation or malnutrition or other such disadvantages to ensure they're not mentally prepared, although that might be excessively cruel.
Naturally these all assume and require solitary confinement, unless you want to put multiple baddies in the same spot. So long as attacks aren't lethal, it shouldn't be too much of a problem, right?
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After years and years of genetic advancement and research, a group of cutting-edge scientists have finally perfected the technology of shapeshifting. They can blend select DNA strands of a given animal with the DNA of a human egg in order to create a *single-animal* shapeshifter. While the ability to transfer from human to animal is undeniably magical, the story covers the magic with a veneer of science, and the characters consider it science rather than magic. Most of the technological development up to this point was entirely scientific in nature with no help from magic, and the world has technology that *almost* achieves this point. (I am playing with the border between fantasy and sci-fi.)
Given their ambitious (and largely magic-less) scientific pursuits, **what other technologies would likely be developed on the way to discovering this one?**
## GenTech in Solna
This world, and the society of Solna in particular, has long had a serious interest in genetic research. In addition to the shapeshifters as described, there are many other gentech advancements, and plenty of room for more. They breed crops to be more efficient and resistant to disease, they utilize stem cells to heal injuries faster and more completely than we can, and re-purpose things found in nature to suit them at will, such as reimagining whale hearts as pumps.
## The Natural World
At the same time, this society has a huge focus on harmony. The gross excesses that we see in our society, where we take freely from nature without care for what we destroy in the process, are not seen here. There are excesses, as there always will be, but large-scale destruction is stopped and reversed. They pay careful attention to how their use of resources affect the larger world and do their best to maintain the balance found in nature. Not every society in this world enforces these practices, so you would find strip-mining and similar exploitation in some places, but the dominant culture does.
## Communication
I'm reluctant to let this world have the Internet. If the computational power of a computer is necessary to sequence the human genome or any other steps integral to the process of making shapeshifters, then we can have computers, but the extreme power of freely accessible information would radically change my world in ways I'm not prepared for.
I'm okay with radio and similar inventions that make communication easier, but I don't want the universal access to instant communication (or worse, instant recording capabilities) granted by cell phones and the like. So, if possible, I'd like this technological path to not include such free and easy communication.
## To Sum Up
I am trying to make sure that I haven't missed anything - that I don't have people sequencing the human genome who haven't developed electricity. (Aside: They have electricity everywhere that isn't Gare.) **What forms of technology need to be developed, or likely would have been developed, in the process of creating shapeshifters?** A good answer wouldn't necessary list every single technological advancement (the wheel! ironworking!) but instead would cover a general overview of what kind of technology modern people have free access to in different areas of their lives, or perhaps what the cutting edge of various fields would look like.
I have a host of misgivings about this question (too broad? no possible right answer?), but I figured I'd give it a go and see what feedback I receive to improve it. At the very least, I hope it's interesting to discuss.
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**More Questions than Answers**
There are lots of variables to consider in order to be able to answer your question.
Are the shapeshifters in your story primarily engaged in technology and research, but just happen to care about the natural world? Are they primarily a low-tech society, but just happen to have an aggressive genetics science program, aided with a bit of nature magic?
Is the shapeshifting end result from the genetic/magic efforts something of a rarity that they bestow only upon a sub-class of their citizenry, or is it so ubiquitous that everyone is affected?
The "blending" of animal and human DNA sounds as though a single shapeshifter would have but two forms: human, and a particular animal. Is that the case, or is the end result more far-reaching, enabling shifters to assume any animal form?
In your world, is shapeshifting an instant ability, or something that takes considerable time? If the former, you have to decide how to explain matter and energy conservation; or if the latter, you might want to explain with a more biological rationale, possibly requiring less magic or hand-waving. Instant shape changing is practically a super-power, while slowly morphing from one form to another can more realistically deal with the addition or loss of mass.
**Technological Assets**
In my view, the scientific prerequisites to manipulate genetic information, at least in our history, are many and varied. The contributions from physics, for example, led to optics that allowed us to explore increasingly smaller subjects, from insects to individual cells to molecules; with atoms themselves requiring altogether different technology from electromagnetism and chemistry.
It's difficult to imagine a society that would have the necessary scientific prowess to intelligently manipulate DNA and understand the outcomes of complex genomes, proteins, and interactions of countless biological and chemical processes without the ability to share information quickly and efficiently. Though perhaps your world has an intellectual or scientific center, where the best minds cultivate and share ideas without the need to communicate across continents. I suppose you could conceive of a world where scientific breakthroughs are accelerated via magic, and nurtured in a fantastic academic community. (Not unlike how many modern-day conveniences began as ideas in universities and corporations around the world.)
In many settings where shapeshifters exist, they are often portrayed as nature-loving. They're protectors of flora and fauna, often understand animals on a level "normal" humans cannot, and are frequently secluded and mysterious. Perhaps the only difference in your world is that they arrived at their position in no small part due to technological focus and perseverance. Their principles of understanding and safeguarding nature was the ultimate drive to integrate it into their very lifeblood.
What other byproducts might a society like this have, if their ultimate goal was to achieve shapeshifting ability? Certainly as you mention, their command of GMOs would be second to none. High-yield crops with all the desired attributes: pest resistance, drought tolerance, negligible side-effects, etc.
The biotech industry that we have today in the real world I think provides a glimpse of what they might have perfected: organ and limb replacement, cloning, surgical and medical excellence, pathogen-fighting supremacy, and so on. The diseases we currently struggle to understand and fight might be mere shadows of their past.
**Scientific Setbacks**
Perhaps this culture has sacrificed other aspects of discovery and innovation in pursuit of their chosen proficiency. It might be interesting to consider what their weaknesses might be, from a technology perspective. If their history has generally enjoyed peace, perhaps they have limited or nonexistent weapon technology (though their bioweapons, if forced to develop them, would probably be formidible). As you already stated, perhaps their communication technologies are comparatively weak. Their understanding and knowledge of the galaxy and universe might be laughable. It's conceivable that their idea of travel is firmly encapsulated in the abilities and forms of animals, leading to underdeveloped versions of combustion, rocketry and other forms of energy-to-motion conversion.
I think advanced understanding of biological systems and genetics requires good foundations in chemistry, physics and mathematics, but it's conceivable that they might have missed certain developments in areas we are proficient. That said, the precursors to working with delicate, microscopic systems must certainly involve basic metallurgy, mechanical systems (pulleys, wheels, levers), and puzzle-solving.
Humankind has often been driven to discover and innovate amidst the pressures of war, famine, and difficulty. What are the historical adversities of your society? Perhaps these can help dictate what they might have developed (accidentally or not), and what they might have missed.
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Electricity isn't strictly necessary, although it would certainly make things easier.
Fundamentally you need tools that allow you to scan and analyse DNA. You need tools that allow you to modify and merge that DNA. You need some way to make the resulting creature viable. This could all actually be done using bio-tech and have no other technology needed at all.
The problem would be explaining how the bio-tech was developed in the first place, once you have it you don't need anything else but without it you can't develop it.
You are going to need computing power, optics for magnification, DNA sequencers and something to design and build your new DNA modification. The trouble is that each of those things is itself dependent upon a whole sequence of other similar things.
So really you are talking modern technology levels (or 1990s at the minimum) and then some extra advances in genomics and genetic manipulation.
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Because Boron is directly to the left of Carbon and Nitrogen is directly to the right of Carbon on the Periodic Table Boron-Nitride has the same types of bonds and so as carbon and so in combination with other elements it can form Molecules with the same shape as carbon atoms. Because Boron-Nitride forms molecules with the same shape as carbon molecules Boron-Nitride has been suggested as a possible alternative to carbon as a building block for Extra-Terrestrial life.
Ammonia could also be an alternative to water as a solvent for Extra-Terrestrial life as it is also a polar molecule that in liquid form is capable of dissolving a variety of substances including organic substances.
Even at the temperature of Liquid Ammonia Diborane is a gas meaning that it could get into the atmosphere of a planet that has high concentrations of it.
The only problem for Boron-Nitride being a building block for Extra-Terrestrial life is that Boron is very rare.
Is there any way a planet could have high concentrations of Boron in its atmosphere and on its surface? Would Diborane have any effect on the temperature of a planet? What color would the sky of a planet with Diborane, Nitrogen, and Ammonia in its atmosphere be?
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Nitrogen and ammonia? No problem.
Diborane? Not so easy. The problem is, diborane has a positive enthalpy of formation. That means that it prefer to remain as boron and hydrogen separately. Despite that, it is less reactive than you would expect. Furthermore your atmosphere has a compatibility issue, diborane reacts with ammonia to form the diammoniate salt.
On the other hand, the planet in question has life, and that is important, as such places tend to not be in thermodynamic equilibrium. We do for instance have large amounts of flammable material combined with an atmosphere containing oxygen. If some process on the surface constantly release new diborane to the atmosphere it is not going to be a problem.
As for the colour of the sky, things start off normal with ammonia and nitrogen: Transparent with white clouds. I had a hard time trying to find spectral data for diborane, but I found a lot of images showing nice, green flames:
[](https://i.stack.imgur.com/ltyq0m.jpg)
Probably not hundred percent accurate, but I like to imagine an atmosphere with a weak green glow.
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In a world much like our own (basically, identical humans, points in history, etc) where humans live 80 or so years, we have developed a wide array of languages around the planet as well as very different accents in each language. In fact some accents are so different that it can actually be difficult to understand each other even if you are speaking the same words.
How would an immortal speak with his fellow human? Would he try and have an identical accent as to the current person he is talking to? Would he develop his own personal accent that sounds like none other? Would he retain the accent of his time and sound out of place to the people he talks to?
I would like to know how such a man/woman would be in this situation from different places in time such as:
* The Stone Age
* The Middle Ages
* The 21st Century
How would these 3 different immortals from these 3 very different times converse with someone in the near future from us such as the year 3000?
How would they converse if they found each other?
The immortals are human in all but how they age, meaning: They are born normally. They grow and age normally until they reach their peak, like their mid twenties to thirties or what have you. Once they reach their peak they stop aging, their cell's are replaced as rapidly as they die, this does NOT include huge losses of cells such as limb loss, so if the immortal loses an arm or a leg, it's gone for good. They scar normally and they also can still get sick, though I would imagine that they would heal at a more rapid rate.
I haven't decided how I want their memory to be, I'm leaning closer to them remembering everything, however answers are more than welcome to assume they can't store everything indefinitely and will eventually start to forget things for good.
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It only takes a few years at most to learn a new language, and if you were present for the entire development of those languages, you would be fluent. Odds are that the first two immortals are fluent in nearly all languages, or at least on their continent, it really depends on if they moved.
as for accent, I've developed an accent that isn't my natural one before from talking to people with that accent and that only took half a year or so, so odds are that the immortals accents are that of the people around them.
What also matters is their mindset, I they have accepted change (as thy probably have over thousands of years) then they will probably also act and talk generally like the people of the current age. The 21 century immortal may not have accepted change yet though, and may have the same mindset as the old man down the street who keeps repeating 'back in my day...' these kinds of immortals would probably speak in a more proper and formal way, preferring not to use slang and popular phrases.
Then there is their opinion of man, they most likely have one of three perspectives;
1. they despise man and their inability to learn from there mistakes
and selfishness,
2. they believe they are higher than man and not a part of man,
3. or they could enjoy the change and development of man over time,
their achievements and learning up to this 3000AD.
That's a basic and bland summary but I hope it helps.
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This is a difficult question to answer without making at least a few assumptions.
Immortal means you don't die, but how does this process actually happen;
1. Cells die and are replaced with 100% efficency
2. No cells die and no cells are replaced.
Each of these have issues; If all cells are always replaced then you can chop of an arm and it would grow back, making an infinite (and quiet disgusting) food source - and reading conservation of energy. If no cells ever die then what happens when you get shot, is your skin impenetrable? Etc.
I'm going to assume that we're somewhere between the two processes, closer to option 1. Our cells die and are replaced but some what slowly.
So my first point of concern is memory. Humans have a lot of storage in their heads, but it's not finite. If you don't use a language for a very, very long time it may become lost to you. This differs in the option 2 as once our brains have reached capacity we simply can't learn any more.
If we stick to option 1 a likely course of events is each immortal will easily be able to talk to their contemporaries but will eventually forget their earlier languages.
So a stone age man can certainly speak to our 21st century guy, *but* the stone age man could intentionally use an older language if he wished to cancel something from the 21st century guy.
Accents are a strange thing. You can pick them up almost overnight or never lose them after leaving home at age 8. However I would suspect the immortals would pick up a trick or two over the years when it comes to controlling their voice. Impressionist can make themselves sound like they're from Oz or Ohio, usually within the same sentence if they want to show off. Our immortals would likely be able to do the same; their 'natural' accent would probably be based around where they have spent the majority of their time over the last few years, but they could easily switch to another accent at a moments notice.
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**Background**
You are a member of a world of super-beings. Not everyone wants to be a god but those who do typically enroll at a Godiversity. They take classes in all sorts of things such as Ethics, Multi-dimensional Thinking, Alternative Physics and Creatorship.
You have decided to set up a business to help aspiring god-students pass their courses.
A desperate student, *YeeHaw!*, has just landed in your office. His term-assignment for "Creation 101" is due to be handed in in a mere 10,000 years. He has already been running his creation for 90,000 years so it is well under way.
You glance over his write-up so far and have a peek at his creation in action.
**Here's one problem you noticed.**
Student *Y!* neglected to specify all the laws of physics in advance. This omission led to one scientist discovering that light is made up of particles and another finding that light consists of waves. Sorting that out so that they were both right was a bit of a headache. You had to come up with a solution and implement it in the World's physics. You had to make it plausible enough that the World's future scientists would be able discover it and make a feasible theory about it. Problem solved.
**Question**
What other mistakes would a typical student make and how can you fix them?
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> Each answer should have the following sections:
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> 1. A brief description of the nature of the student's oversight.
> 2. A brief explanation of why this poses a problem
> 3. Bare bones of the proposed solution.
> 4. A short discussion of why it works and of any issues that might need to be addressed.
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**Student Oversight**
YeeHaw! neglected to work out what the universe is made of beyond crude visible properties.
**Why this is a problem**
This worked okay for a while until the inhabitants discovered that everything wasn't made up of fire, water, air, earth and life as they first thought. The scientists are now finding inconsistencies and it's starting to freak them out. (As it should.)
**Solution**
Since the scientists are confused already, invent and implement a system of statistical physics from which everything is made. Skip any intermediate systems like atomic elements and treat such atomic systems as emergent properties from the statistical physics. Have this physics system cover only what happens at impossibly small scales and not apply in the least to the laws of physics that the scientists are used to at their scale of being. They will muddle over how the two physics system interact with each other and try to explain one with the other. These will always be wrong and people will start to laugh when they the hear the scientist's latest announcement of "We've found the one Grand Unified Theory to rule them all!"
Studying this statistical physics system is impossible without incredibly complicated instruments. Building these kinds of instruments takes a long time, so Yeehaw! will get some breathing room to work on the other problems. Tweak the constants in this statistical system till the same kind of macro-behavior as seen in the Earth, Fire, Water, Air system, but only just enough.
**Discussion**
Depending on the complexity of the statistical physics system, scientists may master it too fast. In their search for the bottom they may induce a bug in the simulation that grants them StudentGod powers.
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The easiest way to deal with this is with a sort of cosmic double-whammy that won't actually solve the problem, but it will grind those mud-dwellers to a halt long enough for them to kill each other off.
* Make a minimum resolution
At a certain point of magnification, no one can tell the difference between yes and no. Your inhabitants will probably call it "quantum state paradox" or something silly. Basically once you get too fine a measure, particles are both there and not-there. Once they reach "the bottom", physics will just sort of peter out, since there's nothing new reliably to find.
* Slowly jack up the speed of light over time
This will completely destroy their ability to do any long-term analysis of the Universe, as well as give everything in the Universe a red-shift on the doppler spectrum.
These two simple techniques will throw the science community into a torpor, as no one will be able to wrap their heads around *why* anything is happening. Those fuzzy dots can stay fuzzy, or you can fill them with another students concept art, since your inhabitants will never get around to actually visiting those places anyway. Since you set these folks up for failure in the scientific progress department, they will eventually start to praise thoughtlessness & anti-intellectualism and go into a series of world wars to prove who hates thinking and reason the most. If you set the minimum resolution low enough, your inhabitants may still discover nuclear fission, fusion, or anti-matter, making the "**BOOM**" that much more assured.
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In a story I mentioned that an AI overlord in 2036 has one of "her" bases in Ethiopia, and now I want to develop that offhand idea into its own story. My AI is equivalent to a very smart human with computer-related abilities like perfect memory, but not completely beyond human understanding. Her short-term goal is to keep people alive and happy, and her long-term goal (achieved by 2037) is brain uploading, ie. getting volunteers to have their brains fatally scanned in so their simulated minds can live in a VR paradise. Other than the above she doesn't have any amazing technology like "instantly-build-anything" nanotech. Once she starts doing uploading, she gets free skilled labor from the people who've already signed up, but probably doesn't have more than a handful of robots before around 2040.
So, Ethiopia. Where does the AI put her base within the country, and how does she get adequate raw materials and energy so that the place at least breaks even financially? I see the place has cheap labor, hydro power, severe corruption, and poor infrastructure. Can she plausibly mine the materials for making more computers and solar panels (or other energy sources), to support a self-sustaining operation with growing electricity and hardware needs? Assume she and her allies address the problems of politics, religion, defense &c that's what the storytelling is for. Also assume she's got a significant startup fund on the order of millions or tens of millions of dollars, so she can build something but hasn't got gigantic factories or the like yet.
**Edit**:
Yes, the country could be improved by the 2030s, though so far I haven't decided anything in-universe other than that there's some nasty warfare going on in the area. That could coexist with decent prosperity elsewhere in the country. I'm assuming the place isn't much better or worse than it is today; various NGOs' rankings put it in the "terrible but not a compete hellhole" category. One thing not directly relevant to my question is the rule of law and what it means for the ability to build stuff safely; there's some storytelling to be done there. I'm asking about (1) where to build, and (2) whether it's plausible to mine/farm materials for a mostly sustainable base. I assume the AI and friends work out solutions to the many social problems.
Re: technology, the AI isn't tied to one piece of hardware; she's got several small bases like small R&D companies in Canada and the US, and can distribute her operations through a mix of the Internet, heavy encryption, and "sneakernet" sneakiness. For power/cooling I don't know specific numbers, but figure 2030s computers are "better but more improved in efficiency/size than in raw power", which might just be unimaginative continuation of current trends. Late in the existing story's timeline I say there's at least one major base with all kinds of security, but it's not the only one, and there's some low-level computation being done on widely marketed handheld gadgets.
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> Assume she and her allies address the problems of politics, religion, defense
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I believe this implies that answers should address how the AI manages **internal infrastructure** meaning that humans will, at least in the beginning, manage military affairs, international relations, and other matters that directly effect the economy *less immediately*, as self-sustenance is a future sub-goal.
## Short term goal
Making everyone happy is **impossible**, but being an AI it will likely try to maximize human happiness, leading to a myriad of secondary goals.
* **Learning** So that the AI can better understand, estimate, and perform in general. That leads to...
* **Hardware Upgrades** To ascend further than "intelligent human" and "not completely beyond human understanding". Which leads to...
* **Research of Technology** To enable said hardware upgrades and options to problems. Which means we need...
* **Workers and Researchers** Human labor and scientific research (directly overseen by the AI), but for that...
* **Money and Political Stance** To put in place educational facilities, "educational facilities", research centers, and factories.
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> I see the place has cheap labor, hydro power, severe corruption, and poor infrastructure.
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Assuming the above is true (regardless if it is), poor infrastructure will be the highest priority obstacle. No matter how intelligent the AI is, until it can manufacture autonomous drones, the **AI is limited by its workforce**. While an AI can manipulate corrupted officials and develop better power generation, an infrastructure will be the AI's primary source of progress. The AI will need to stave off its long term goal with **improving quality of life, but only within Ethiopia**. The last part is important as, with the improvement of life inside Ethiopia, there will be a positive effect to net migration, thus increasing the potential workforce, leading to more power... Repeat.
## Long term goal
Unfortunately, the long term goal of VR paradise conflicts with the short term goal as VR does *not* quantify as maximum happiness, however, assuming this overrides the short term goal...
**TL:DR** The AI should set up shop in an underground bunker, and improve the economy, technology, and quality of life using its advanced computing until VR reaches a sufficient development level. More people arrive, more workers, more tech.
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Assume scientists in the near future create a successful clone of a Neanderthal. This is not too far off since we have already [mapped the Neanderthal genome](http://www.wikipedia.org/wiki/Neanderthal_genome_project). Now, assume that these scientists decide to bring Neanderthals back from extinction by cloning many of them.
* How might our current society react?
* Would human rights laws apply to these Neanderthals?
* Would these Neanderthals be completely susceptible to most human diseases and therefore suffer the fate of the 1980 AIDS patient (simple diseases killing them).
I would also like to know how far off this might be in the future?
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There is one thing that a lot of your questions depend on, and that is: how intelligent is the Neanderthal? Is it more intelligent than a chimp, but still an "animal" in terms of understanding complex thoughts and communication? Is it just less intelligent than the average person but still capable? Or, intelligence-wise is it just like any other person?
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Depending on the result of the above would determine if these people could be taught and schooled and introduced into society just like any other person. If they had the capabilities to be schooled and introduced into society but weren't, I'd imagine a lot of activists standing up for the Neanderthals rights. If it turns out Neanderthals are "animal-like" in nature, they would probably be treated as such - and probably with a *lot* of scrutiny over how they are cared for.
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Completely depends on the above
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I would imagine that they have some sort of immune system which is capable enough to fend off diseases. If not, it's probably why they're extinct. The only exception is if they are raised in a completely sterile environment and then are exposed later.
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I don't have the knowledge required to feel comfortable even guessing the answer.
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TL;DR:
**Cloning is so far away, that with any luck, General AI beating human intelligence will become available sooner** - So both Homo Sapiens and cloned humanoids would be "lesser intelligence" subject to whatever "greater intelligence " (GAI) will decide is good enough for both.
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You are trusting journalists too much, or watch too much TV. Your assumption is wrong.
Cloning humanoids is way off in the future, we are not near close, even with simpler and much better understood mammals.
Even cloning simpler animals like [sheep Dolly](http://en.wikipedia.org/wiki/Dolly_%28sheep%29) is extremely complicated. 95% fetuses are not viable, and most of the few which are have severe diseases causes by wrong genetic signals. Dolly has arthritis from age 4, and has to be put down.
And in this situation, we had really good understanding of biochemistry, perfect fresh DNA, fresh egg to put in into, and real sheep mother to carry the embryo to term - we would have any of those for Neanderthal, so there are many more things to go wrong. So rate of success would be much lower, you will need to engineer many thousands of embryos to get one viable.
**Cell division during pregnancy is complicated biochemistry dance, where cells send chemical signals to each other to guide proper formation of organs in neighboring cells.** Slightest mistake in signaling, and organ is misformed, and embryo is not viable, or has some disorder.
And those are only technical obstacles - there are many more ethical obstacles, as you correctly noted.
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Simply put: Given the current state of Mars, how plausible is it that any intelligent life would be several miles below ground?
I do not have any other requirements for such a race, I'm just asking about the possibility to find something there that would be able to communicate with us.
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I would say that I find it unlikely that there is enough energy underground to provide enough to sustain advanced life forms. And by that I would include rodents. There would have to be a terrarium kind of environment. Even here on earth living cave systems breath air to keep Oxygen moving, have fresh water sources flowing through etc. Mines without proper ventilation kill swiftly.
So for a natural system everything would have to be very well balanced to keep any reasonable level of life going. There also would likely be some kind of marks on the ground like gofer mounds where the 'living' spaces where dug out.
However, having said that, I think it is possible (though not terribly likely) that an evolved race could have dug down after it became a problem of the atmosphere departing. They would have to be fairly advanced to have an entire society living below ground, keeping fed etc. I would guess if such a thing where true, most would be somewhat close to Olympus Mons, for the geothermal energy that could be available.
It would be a useful place to have a science station to observe life on earth. I would also think that if the race was advanced enough to recognize the issues facing it of a depleting atmosphere and create a subterranean living conditions to last eons, then I would think it likely that it could try and colonize one of the close planets such as Earth...
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The deepest mythological archetypes in my Earth-like world hint at a wondrous and terrible disaster in the ancient past. ~10 tya a celestial body (perhaps a small, second moon, or a wandering asteroid, either suits) broke apart in the sky, well in sight of my primitive humanoids, and formed a beautiful terrestrial ring around the planet.
Is it possible that humanoid life survives what I presume would logically be a period of acutely raised meteoric activity? I am a layman to planetary physics, but I shall try to enumerate relevant details:
1. Assume all unmentioned characteristics mimic Earth.
2. My humanoids do not have any special advantages over humans to help them survive meteor impacts or the plantery changes that follow large meteor impacts.
3. Assume, however, that they are prodigously lucky at the very last moment. If there is "a chance" that a significant portion of the population lives by some unorthodox move, like going underground, they do.
4. Ultimately, the real question is, is there "a chance" that a significant portion of the population survives. Not just a few dozens or hundreds across varied continents, but enough that 10,000 years after the event, they're capable of a regrowing into resembling medieval society?
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I think you are glossing over the points that would actually cause the extinction event.
You can probably engineer some sort of trajectory for your quasi-Theia such that it won't immediately shower the planet with debris. So suppose there is such a configuration, where the incoming protoplanet breaks apart due to the Roche limit and only a insignificant fraction of debris immediately enters the main planet's atmosphere. All you have really done is move the date of the end a few years out.
Planetary disks are inherently unstable, even more so if it is made up of hot debris in irregular orbits.
To gloss over some physics, the internal friction of this thick disk will be enormous and slow it down as a whole. So all this debris is just gonna crash down on the planet regardless. Whatever fraction of the original incoming protoplanet the disk is made of, most of that will rain down very quickly after the initial event.
I think, if you want the visuals, a better approach would be to have some moon be very active to the point where it generates a disk made up of ash and dust. Visually that will look somewhat similar, but does not come with the whole extinction stuff.
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In a scifi universe I'm currently writing up, a colony was established on a weird world. strangely, it's a habitable planet with an extremely shallow sea, with an average depth of 4 meters, excluding the occasional 2 km deep rift valley. The planet is also dotted with chains of islands, mostly small piles of sand, the largest island is about the size of Earth's Madagascar Island. Volcanism is rare despite the evidence of a magnetosphere and tectonic activity.
But what would the climate of a world that is nearly all shallow ocean be like? How would the currents work? would it be a sunny tropical paradise or a stormy hell hole? And would it be a good place to put up a beach resort for human colonists?
Specific characteristics of said planet
* 90% the size of the earth
* Gravity of .95 gs
* the surface is nearly 99% ocean
* ~1 Au from its parent star
* said parent star is a little dimmer than our own Sol
* deep open oceans are rare on this planet, with most parts going no deeper than 20 meters
* habitable, complex multicellular life is present, and an atmosphere like Earth's is also present
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The climate on your world would, to a good approximation, be similar to that on Earth. The oceanic currents would be different, but in broad terms its an Earth analog, Earth is after all 70% ocean. o
Obviously the effects of land masses / mountains would be missing so just extrapolate Earth's oceanic climate around the entire planet. Might as well take the Pacific Ocean as a starting point as it more or less covers half the planet anyway.
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I think planets with (carbon-based) life but shallow oceans make for an interesting combination. Organic matter and nutrients from dead matter in our world descend deep into the ocean through the process of [marine snow](https://en.wikipedia.org/wiki/Marine_snow). To the best of my knowledge this explains why on our planet the CO$\_2$ concentration has been able to get so low (100's of ppms in stead of 10's of percents): the carbon was fixed from the atmosphere by photosynthesizing cyanobacteria and then fell to the ocean floor by virtue of the overdensity of the dead organic matter. On your planet, there will be an abundant ecosystem on the ocean floor efficiently recycling (burning) whatever is deposited there and so the atmospherical $CO\_2$ will likely stay very high. So the greenhouse effect is going to be very strong here (but if the star is sufficiently dim there may not be a problem) and the atmosphere not exactly breathable for humans.
Of course you might circumvent that predicament by having a weird primordial chemical composition for your planet (very scarce C), but you're probably finetuning then.
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I found out about Ferrovolcanism on asteroids and its a pretty neat idea for a space sci fi setting. Moreover, I have come up with a hypothetical way that an asteroid could be heated by induction heating.
[](https://i.stack.imgur.com/QuEwv.png)
Above is a crude illustration of this hypothetical setup.
There are two asteroids, A and B. A is much large made of materials the could generate a magnetic field. And B is much smaller, orbiting around A, its orbital path is illustrated in blue. A has a magnetic field which is illustrated in red with its poles, but A also rotates, and its rotational axis which is in green is perpendicular to the magnetic field and spinning faster and in the opposite direction B is orbiting. This should make B experience an alternating magnetic field causing Eddy currents to heat up the deep metal core of B slowly, and if B is poor at radiating heat it will eventually build enough heat to cause an eruption after many centuries or eons.
Besides the rare chance of this setup existing, could this realistically heat up an asteroid and cause an eruption.
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I doubt such a setup would last long enough to store enough energy and cause an eruption: if you ever used a dynamo on a bicycle you know they drag a lot from the wheel, stopping it quicker than just air and bearing drag does.
The same would happen here: as soon as the currents start flowing, they will do it at the expenses of the body's momentum, meaning it would alter the orbit and not be there for long.
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**It might not need to get that hot to erupt.**
Your setup clearly can heat the bodies involved. We are used to thinking of volcanoes spewing forth really hot stuff like lava and hot ash and winged kaiju. But colder places can have volcanoes that spew colder stuff.
[NASA Discovers "Lonely Mountain" on Ceres Likely a Salty-Mud Cryovolcano](https://www.nasa.gov/feature/goddard/2016/ceres-cryo-volcano)
[](https://i.stack.imgur.com/Gu2j5.jpg)
>
> Although the volcano is not active now, the team was surprised that it
> appears geologically recent. Young volcanism on an isolated dwarf
> planet is a surprise, as usually only planets, or satellites orbiting
> around them, have volcanism. Also, volcanic eruptions require bodies
> to be rocky, like Earth or Mars, or icy, like Saturn's moon Enceladus.
> Ceres is made of salts, muddy rocks and water ice: exotic and
> unexpected ingredients for volcanism. Ahuna Mons on Ceres indicates
> such physical and chemical limitations to volcanism are only apparent.
> As a consequence, volcanism might be more widespread than previously
> thought.
>
>
>
I like the idea of your asteroid's volcano spewing fizzing slushy mud. If you were nearby it would be like driving through freezing rain, except brown and yellow with metal sulfides and oxides. The liquid might be liquid ammonia which is even colder than water, or even substances we usually think of as gases like methane / ethanes. The erupting mud would probably stick to stuff and freeze again once it was out. It would take the paint off. It would be an unholy mess.
No reason I can think of that winged kaiju should not pop out too.
[Answer]
The [Ferrovolcanism](http://www.sci-news.com/space/ferrovolcanism-07076.html) is pretty neat. I had always thought of asteroids as being cold, but in the early formation they would be molten and as they cooled they could have spewed molten iron. Going down that rabbit hole a while, apparently for the [asteroid to have a magnetic field](https://www.space.com/28319-asteroid-magnetic-fields-earth-core.html) it needs to have a molten core. And that molten core lasts several million years. So it appears if your solar system was young, you could have molten cores and a magnetic field.
From an orbital mechanics point of view, I think it would be difficult for one asteroid to orbit another asteroid for a long time in a stable way. As L. Dutch points out if there was significant eddy current heating the orbit would also decay.
My guess is that the amount of eddy heating would be relatively small. There is a paper that seems indicate that Tidal heating for the moon Io orbiting Jupiter is much larger than the electromagnetic heating. Another [paper](https://doi.org/10.1016/j.icarus.2021.114360) seems to think in our solar system it is small but there are some other papers that claim magnetized stars can heat up [planets](https://ui.adsabs.harvard.edu/abs/2018ApJ...858..105K/abstract).
But maybe for the proposes of your story you don't have to have the complicated orbit, just the molten core of the asteroid and as it is cooling down it erupts.
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[Question]
[
Let's say we have a society with people (living creatures with human-like intelligence) of vastly different sizes, from mouse-sized to elephants. People have jobs like us humans do: some physically heavy, some require detailed craftsmanship, some intellectual work.
In our world, small animals have populations that easily dwarf human or even elephant sized species. Would it likely be the same in the supposed society?
[Answer]
# Logistics and Reproduction: r and K Strategies
The difference in number of creatures is mostly due to resource requirements and the strategy for reproduction. Both of these reasons should be factors in your world when you want it to be very sensible.
Obviously, you can have a higher population of a creature when it requires less food, shelter, and water than a larger creature. This is simple logistics/economics. It stands to reason that, everything else being equal, the small folk will eventually outnumber the big folk due to resource requirements.
Concerning reproduction: many biologists look at the various reproduction strategies of species as a spectrum between investing a lot of resources in few offspring and investing few resources in many offspring. It's called [r/K selection theory](https://en.wikipedia.org/wiki/R/K_selection_theory).
In short, when a critter is small and life is cheap, it is better to have a lot of babies and therefore have a higher population. Some number will make it to adulthood by mere chance. When life is dear and a lot of stuff goes to each child, it is better to have fewer and take good care of them.
# What About Society and Thinking?
This society of big and small folk ***could*** buck these trends. There would need to be some artificial pressure for little people to not outstrip the large people in population. Maybe they require some more rare resources which limits their numbers? Maybe there is some policy or cultural pressure to only have a few kids?
[Answer]
Short answer yes. The larger you are the more resource you need. larger animals Who reproduced too quickly could easily go extinct If they didn't spread out because they would consume too many resources.
On the other hand Smaller animals are usually weaker and more in danger then larger animals and are usually someones food resource. Because of this it makes more sense to have as many kids as possible since so many of them are going to die.
[Answer]
**Killing intelligent species is a crime**
In our world, humans are intelligent and animals are not. So killing humans is a crime while killing and eating animals is not.
**Unlawful killing will cause war**
In your supposed society, all creatures are intelligent ***(living creatures with human-like intelligence)***. Killing any intelligent person (of any species or race) will be a crime. Big animals will not be able to eat small animals as they will protest and force the authorities to pass laws for their protection otherwise there will be a war using weapons.
**Distribution of resources**
All species are intelligent so they will demand fair distribution of resources. Unfair distribution of resources will lead to chaos, revolutions, wars as happened in human societies in colonial era.
**Population will adjust to resources**
If there is no colonialism, slavery, oppression and all species have equal rights on all the resources, then population of all the species will adjust to the available resources.
] |
[Question]
[
The temperature, pressure and radiation are all not optimum on Mars for life. But if the pressure were several fold higher (20-30 mbar instead 6 mbar), the temperature 5C higher, and with less radiation could we manage an open air lake seeded with all the life needed and fish? This could provide food for a colony but I want to make sure it is doable.
[Answer]
## You can not have an open air lake on Mars
Lower gravity causes gases on Mars to escape off into space. It's solid core also means that Mars has no magnetosphere so solar wind speeds up this process. Since you are assuming slightly higher air pressure and slightly less radiation, I will suppose you gave mars a molten core, but your low gravity will still be a very big problem. On Earth, water vaporizes, gets caught in the atmosphere by gravity, and eventually becomes dense enough to form rain and come back down.
Mars will still have evaporation, but the air will never get thick and cold enough at the same time to precipitate; so, an open air lake will quickly dry up.
## As for Fish as a Food Source on Mars
If you want an "open air" lake, it will need to be part of some contained habitat. Keep in mind however that open lakes are REAL inefficient sources of meat. In a natural lake, most of the biomass is not things that humans eat; so, you generally only get about 25-100 lb of meat per acre per year. For comparison, 1 acre can sustain a production of about 1700 lb of chicken per year or about 3000lb of wheat or soy or 50,000 lb of potatoes making open pond fish farming a bad source of food anyway.
If you insist on fish, you will want to really min-max how your raise them. If you have a catfish farm, you could use reflectors to heat vertical glass tanks, and add sewage to encourage rapid algae growth providing a good food source for a dense fish population. Mechanically aerating the water is also a must. This way you can get a good sized meal fish that eats an easily grown high energy primary producer. Done right, you could probably achieve close to chicken levels of efficiency with fish, but not in an open lake.
] |
[Question]
[
I read a story about a Mars war. There was a lot of shooting by the Martians, which made me think about insurgents weapons on Mars. It makes no sense to me for all these guns to be accessible. Not having hunting or armies beyond perhaps a police force, they wouldn't have much in the way of guns. So what could they use that would be effective against gun armed Earth oppressors.
Slings seem a great idea, I can sling a stone over 100 mph on Earth. The main drawback with slinging is air resistance limiting range and slowing the missile. The place seems to be littered with rocks if you run out of better ammo.
I'm no great shakes but [in antiquity slings outranged bows](https://en.wikipedia.org/wiki/Sling_(weapon)) and you can make one out of just a strip of cloth. So it's easy to conceal unlike a bow and arrow.
To me they would seem an excellent weapon on Mars with less gravity and next to no atmosphere.
Is there anything wrong with this idea?
Unsure where people get their rate of fire ideas from. [I can sling every 4 seconds](https://www.youtube.com/watch?v=knnPkD7AEBc), which is not close to a crossbow and is superior to a bow. That's a relaxed pace, unsure what it would be if I tried for speed.
[This is an example of how simple an effective sling can be.](https://www.youtube.com/watch?v=mqu-plfFFj4)
**Please refrain from answering if you have no idea what a sling is capable of, or how it is used for anything other than target practice.**
[Answer]
**It could make a good story.**
Slings could be exciting especially if they arrive in the story unexpectedly - of course you would show your bored Martians practicing with the slings at the beginning of the story. They are better than just throwing rocks, which could be exciting too. You could probably throw a rock a long way on Mars. Or one of the Martians could have a [staff sling](https://en.wikipedia.org/wiki/Sling_(weapon)#Staff_sling) which offers more leverage and power than a conventional sling.
For the story I think the appearance of slings in the story would be more exciting when guns became unavailable or there were not enough to go around; the slingers account for themselves well. The weapon of David has a fine track record of unexpected power and success and you could tap that for your story.
If we are really making strategy for our Martian rebellion I think I will go with 3d printed oxyacetylene air rifles.
[Answer]
Crossbows
Crossbows have a similar fire rate to slings and have better penetrative power. They also leave something sticking out of the target that will cause more damage if they move too much. They can be made in any garage shop with a supply of steel, spring steel, and cable.
Guns
There is no reason that the rebels can't make guns. There are new reports of villagers in Afghanistan making guns with fairly primitive tools ([wiki](https://en.wikipedia.org/wiki/Khyber_Pass_copy)).
This is a "Kyber Pass Copy":
[](https://i.stack.imgur.com/DCMZk.jpg)
There is another image of long arms but it won't post here. You can see it at the wiki link above.
[Answer]
## Improvised Combat Robots and Propaganda
This is somewhat dependent on the history of technology in the setting. If you want to write The Gulag Archipelago on the red planet, slings fit better. However, if the setting assumes that automatisation and robotics didn't came to a near total stop in the early 21st century, combat bits are the way to go.
Given our current trajectory we'll use a lot of automation in space colonisation. Some Mars colony is in my opinion unlikely to have a large proletarian class. The lower classes simply don't have the resources to get offworld. Robots are cheaper. So a Martian colony, let's call it Teslatown for no reason in particular, is going to have a very rich upper class, whose economic base is still on old Earth. The rich are on Mars because they can afford it. The majority of the population will be in the middle class, scientists and technicians and so on.
So why do the Martians revolt? Fundamentally because Teslatowns investors have interests perpendicular to those of the educated, idealistic and pioneering colonist types. **These demographics are in my opinion crucial in understanding the kinds of weapons the Earth security forces will face.** Some 16 year old Palestinian kid with no future might yeat rocks at the evil Jews. In the best case he can hope for is getting double tapped and creating a scandal. This way he would help his people the most.
The Martians aren't desperate and without a future, they are annoyed and disappointed. Additionally they have a lot more to loose than someone from the lower classes as well as a lot more historic and technical knowledge.
Armored construction bots, cleaning bots dispersing toxic chemicals and delivery drones with explosives performing precision strikes will be among the things the people of Teslatown can muster with relative ease. It is worth pointing out that the security will most likely be equipped with small arms and riot gear. There is, as you mentioned, little reason to have guns on Mars. There is even less reason to have anti-tank weapons.
**In warfare one targets the enemy's weakness with one's own strength, preferably in an overwaeling manner. Go big or go home.** The security forces face a hostile population, inadequate weapons and supply lines so long that one would rather invade Russia in winter. Additionally the Corporations in charge face the issue of the PR desaster nuking the place from orbit or landing Espatiers to retake the place block by block would be. The rebellion isn't run by a bunch of fanatics who want to establish a chaliphate. **Unless the rebels are stupid (which I established they shouldn't be) they will offer very reasonable demands.** Establish a parliament, oversight of corporate policy, guarantees to participate in the colonies economic growth, legalisation of unions, no foreign security forces, better healthcare, those sorts of things. The goal isn't to kill every last enemy, it is to make concessions far more attractive than enforcement of peace.
Finally one must consider the weapons one employs in the context of the campaign as a whole. Strategy and economy's win wars, tactics only decide how much resources one has to throw at a given obstacle. **The TOP THREE of this campaign will be 1st: controll of the narrative / public perception, 2nd: seizing the means of spaceflight and production and 3rd: elimination of domestic resistance.** Whatever weapons you employ will influence 2 and 3 very directly, but 1 in a secondary manner. Putting loyalists and security forces under house arrest by hacking their accommodations doors, making it attractive to declare loyalty to the rebellion by making it the winning bet and ensuring communications back to Earth show a very positive picture of the rebellion and a dire picture of Teslatowns oppressors until they sign the deal you want is how I would do it. **Sling and molotov equipped lynchmobs raiding the Earther District while robbing, murdering and rapeing anyone are detrimental to this strategy.** Combat robots and PR campaigns will require fewer individuals and will be more impactful.
] |
[Question]
[
**Disclaimer**
I've had a look and the other Large Turtle posts seems to be world based or assuming the turtle already exists.
**Question**
My question is how large could an island sized turtle reasonably get and what ecology would reasonably be needed, eg large amounts of surface algae/plant life.
**What have I done?**
Based off of a mostly wild guess the turtle would need to be around the size of 1-2 city blocks if we presume the "locals" can tame and somewhat influence the turtle to make landfall periodically. This is where the locals would gather supplies (wood for fire/repairs and the like). I'm imagining that the locals diet would consist of a large amount of fish and sea-based foods which can be acquired from the turtle-back.
**Presumptions/Goals:**
* The turtle will naturally want to swim on the surface, this won't be a "trained" thing the locals teach it.
* It should be large enough to "house" a "small tribal settlement"
* The "locals" know it's a turtle
* The settlement are happy to work symbiotically to keep the turtle alive, even as much as "taming" it to cause it to make landfall periodically for "supplies"
* Ideally some form of tropical habitat, but not required if another habitat makes more sense for *reasons*
* Locals have tribal or at most bronze age level technology with farming being little to none due to being primarily turtle based and no real desire to "settle" on land.
* Presume everything is earth like regarding planet size and maths assumptions
[Answer]
Any animals with classical shapes as we know them could probably not grow much larger than the blue whale in water, or the largest dinosaurs on land. That's because those creatures are/were already pushing the envelope when it comes to [the Square-Cube law](https://en.wikipedia.org/wiki/Square%E2%80%93cube_law).
You can't put a city block atop a blue whale, and I am tempted to stop here and just leave a quote from my own profile in this site:
>
> Your fictional creature is too big to stay alive. Just handwave it!
>
>
>
However, a giant tortoise might have some advantages when it comes to large sizes. For starters, they could evolve a more efficient respiratory system than mammals. The reason being that they could copy mammalian lungs given enough time to evolve, and on top of that [they have already mastered the ninja art of breathing through the anus](https://en.wikipedia.org/wiki/Enteral_respiration). In this way they could have an extra pair of lungs if they can get their rear end out of the water, and they can also take oxygen from the water itself.
Another way this could work is that the turtle could use its shell as a natural flotation device. Since it should only feed on plankton there is not much need for it to be a diver like whales. This allows it to be somewhat hollow, thus for the same mass as a whale, it would be considerably larger. Notice that since your villagers will put structures atop the shell, the turtle might sink a little - they may have to compensate by adding flotation devices of their own to the shell.
As for how much they need to eat, let's nerd this out. [A blue whale (let's assume a 100 tons one) eats about three point six metric tons of krill per day during feeding season](https://seaworld.org/animals/all-about/baleen-whales/diet/). The amount of calories in krill varies; By googling, I found that some sources have them at about 1 calorie per gram, others mention up to 6 calories per gram. Being pessimistic, that means a blue whale eats three million, six hundred thousand calories per day.
So how large a turtle could be to have those caloric needs, so that it can feed where a whale could? [According to this handy table](https://sites.google.com/site/tortoiselibrary/nutrition/guidelines-and-dosages), a turtle's caloric needs seems to grow almost linearly with its weight. A 100kg turtle needs 2,275 calories a day. Mathing it out, a blue whale diet could feed a 158 metric tons turtle, or around 50% more massive than a blue whale. Let's round it down to 150 for now to facilitate calculations.
Again, we want the turtle to be kinda like a buoy. Whales are very fusiform. The fictional turtle here more likely flat like a couple frisbees connected to each other. A whale is as dense as water, which means that a 100 tons blue whale has a volume of 100m3. The equivalent turtle will displace 150 m3 (remember, it is about 50% heavier). Suppose it is flattish, and the shell is two meters high on average - for a very circular shell, its radius would be... about five meters (about 16 feet in freedom measurements). That is not impressive at all... That means about 78 m2 of surface area. That's not the area of a city block - that is the area of a regular apartment in some areas of cities such as London and Tokyo (YMMV).
We need to amp up this turtle. Make it twice as thick (doubles the weight), and double the radius too (quadruples the weight). We end up with a turtle that weights a thousand and two hundred tons, thus requiring 28,800,000 calories per day, and it will have a surface area of about 314 m2. That is still far from a city block size (in Chicago for example a city block may typically be 100m $\times$ 200m, so 20,000 m2) and you are going to have a lot of problems feeding it. You may stop here, and substitute a fleet of turtles for a really large one. They may have coevolved with humanity, eating part of the humans' catch as well as their sewage in order to meet their caloric needs (in exchange for the shelter and transportation they provide). Also notice this creature is waterbound - [it's enough of a Kaiju that it can't walk on land](https://worldbuilding.stackexchange.com/a/127920/21222).
---
So far we have only been dealing with caloric needs and weight. We have not even nerded out the circulatory and nervous systems. You could handwave the latter by taking inspiration from the stegosaur, which was larger than a SUV with a peanut-sized brain. But the more detailed look you put into this creature, the more outlandish it becomes, until you simply have to stop looking for hard realism and start handwaving some bits in order to keep things fun.
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[Question]
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In my fantasy setting there are merfolk who live deep under the ocean and neighboring human civilizations nearby based on iron age civilizations like the ancient greeks and phoenicians.
I would want to know what would be necessary to allow the merfolk to construct and maintain a palace underwater. The palace would be the same size as contemporary human-built palaces, which is during the 500s b.c.
The merpeople can easily obtain building materials from humans as part of trade, and some can magically control coral to change its shape and cause it to rapidly grow.
They have hands with webbed fingers and roughly human-level dexterity.
[Answer]
>
> The merpeople can easily obtain building materials from humans
>
>
>
**A.**
**The Romans had underwater concrete**
>
> More than 2000 years ago, the Roman Empire invented a unique marine
> concrete that allowed for the construction of enormous, durable
> structures – even underwater. Incredibly, the exact chemical
> properties of this concrete mixture have eluded scientists to this day
> – but now, researchers from the University of Utah believe they may
> have finally cracked the code. [Scientists Uncover the Chemical Secret
> Behind Roman Self-Healing Underwater Concrete](https://www.mysterious-times.com/2020/08/07/scientists-uncover-the-chemical-secret-behind-roman-self-healing-underwater-concrete/)
>
>
>
The Roman scholar Pliny the Elder described underwater concrete structures that become “a single stone mass, impregnable to the waves and every day stronger.”
[Seawater is the secret to long-lasting Roman concrete](https://www.nature.com/news/seawater-is-the-secret-to-long-lasting-roman-concrete-1.22231)
**B.**
**Pre-fabricated stonework**
Humans can sink pre-shaped stonework as directed. All the Mers have to do is assemble the building. Gravity will hold everything together - there are no storms or strong currents on the deep sea bed.
[Answer]
You have intelligent traders, who live and work underwater. Those are by far the largest hurdles to large scale underwater construction.
### Once cities exist...
Old cities formed at cross roads close to resources. Food being one of the more critical resources. Once you have cities you will have some group wanting to show how awesome they are with a big building. Could be a church, palace, something honoring the gods, or some combination. Once they are building cities somebody will get the idea in their head to build BIG.
### Where
So merfolk cities will form along trade routes. Primary route would be the surface of the seas/oceans, due to lower friction. Shallow so they don't have to waste time dealing with slow ascents to avoid bends. Shallow tends also to be close to land and thus land trade routes.
Cities need food, but cities don't move, plants don't swim away, so areas that are surface lit. So again shallow areas. Ideally with high nutrient for good plant growth. But away from the down stream of other large cities to avoid water pollution.
### Material trade?
Stone is heavy so it will not be transported far from the quarry. Initial cities would probably be built with stone the was found loose or stone that could be pried out with leavers.
Later cities would probably source from near shore quarries. Where metal tools traded from land people could be used more effectively in air. Rock loaded onto boats/barges then moved to nearly above the construction site and offloaded overboard into the water.
Metal tools would be a major trade item from land fold to merfolk.
Certain decorative woods, ceramics, would also be trade items.
### Conclusion.
Again. Once you have water breathing intelligent traders, cities will form. Once cities form, big buildings will be built. Weather those buildings are local gods or the local lords will be dependent on the culture.
So yes, underwater merfolk palaces are plausible.
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[Question]
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I have a world I would like to use for a fiction I am using, and the free tools I got from google (first page) mostly don't do it well.
The world is a Disc. The landmass is about 475 million square kilometers.
With 60% ocean, and 40% land.
Of the land, 40% is either desert or the arctic, 20% mountainous, flatlands are about 25% and the rest is plateaus, valleys, rivers, etc. Now, the tool does not have to be that specific, but it would be fine if I could at least model a Discworld with the ratio of ocean, land, mountains right. It's fine if it is paid but free is preferred.
[Answer]
[Azgaar's Fantasy Map Generator](https://azgaar.github.io/Fantasy-Map-Generator/) is probably the best (free) map generation tool available.
It's not perfect and it can take quite a bit of playing around with to get the results you want but it is miles ahead of most of the other generators around.
That being said it makes typical spherical worlds. It should be possible to use it to make a discworld but you'd have to take the output and modify it to suit your needs, whether through using some kind of projection or just cutting a circle out of the generated map and calling it your world.
[Answer]
Take a look at the Sid Meier's Civilization game series, now on number 6.
It generates game maps randomly with configurable parameters that may or may not allow matching your choices.
It's round, but projected into a rectangle, so should be easily adaptable to a ring.
It's usually output into a new game under a lot of [fog of war](https://en.wikipedia.org/wiki/Fog_of_war#In_video_games), but look into the modding scene, there may be a fast way to see the whole of it.
] |
[Question]
[
Edit: It appears I've made a mistake with the nature of this question. I accidentally confused this with another idea of mine featuring artificial gills for humans. Assume now that this question is aimed towards humans developing their equivalent for their needs during diving. Incredibly sorry for those who already answered.
I thought I'd try a take for artificial gills for humans. And I've been through some answers here already; bringing up things like:
* surface area
* gas exchange
* maintenance
* branching
While some frowned upon large external gills, I wondered if electrolysis might help.
According to an answer to [How would merfolk insulate an underwater house?](https://worldbuilding.stackexchange.com/a/193260/21222), electrolysis could be used to split hydrogen and oxygen in water to reoxygenate it overall. Possible added benefits could be:
* deterring predation on their gills
* help disinfect them and minimize gunk
* act as a defense
I've elected to place them in large "wings" on their backs, mimicking nudibranchs as suggested in an answer to [Anatomically reasonable respiratory system for human-derived merfolk](https://worldbuilding.stackexchange.com/a/96025/21222).
And apparently saltwater is a good conductor? At least according to others here. So if that means it can easily get out of hand, perhaps a low voltage is needed so as not to commit mass executions of life forms including oneself.
Edit: I forgot to mention, that the gills are not part of the body, but instead a mechanism in place of a normal diving tank. When not submerged, the gills retract into the pack. A tube connects the pack to a sort of diving helmet. This is where science fiction might have to come in. I wanted the helmet to be a sort of biological semipermeable membrane. When in water, oxygen is attracted and absorbed while other, harmful substances are rejected. The "gills" work a similar way. In order to prevent oxygen toxicity, I thought they could be based on a "filler" gas like nitrogen to mimic or own air to help prevent oxygen overload. I remember studying for this and found this article <https://www.sea-people.com/new-blog/2020/3/28/artificial-gills>. But I'm not sure of the effect that electrolysis will have on that, let alone the pressure of water.
I'll attach a drawing at some point to better illustrate my design (no pun intended).
[Answer]
You are not the first person to think of this... Peter Watts uses thid kind of oxygen source in his underwater fiction, including *Starfish* ([full story available on his website for free](https://www.rifters.com/real/STARFISH.htm)) and in a short story [snippet](https://www.rifters.com/crawl/?p=7138).
The rifters in *Starfish* had a lung replaced by a system that does the appropriate gas exchange itself, removing all the problems of bad things dissolving into and out of bodily fluids under extreme pressure, and the latter has a simpler system that produces breathing gas that is inhaled by an unmodified human.
I can't tell which system you're specifically interested in, though note that the former is more invasive and needs a direct gas exchange system with blood pumped through it (a little like [ECMO](https://en.wikipedia.org/wiki/Extracorporeal_membrane_oxygenation), perhaps combined with [liquid breathing](https://en.wikipedia.org/wiki/Liquid_breathing#Diving), avoiding any high-pressure gas stages) to get oxygen in and CO2 out. The latter system uses the diver's lungs for this purpose (effectively [hydrox](https://en.wikipedia.org/wiki/Hydrox_(breathing_gas)) diving). That's obviously simpler and uninvasive, but doesn't solve problems of [gas narcosis](https://en.wikipedia.org/wiki/Hydrogen_narcosis) or [the bends](https://en.wikipedia.org/wiki/Decompression_sickness). I won't go into further detail here, but obviously there are details you need to care about.
Lets consider your design ideas though:
>
> I've elected to place them in large "wings" on their backs
>
>
>
A professional aerobic athlete might be breathing at 150 litres of air per minute at sea level whilst working hard, and this seems like an OK "maximum output" level. About 5% of each lungful is consumed, giving you a peak O2 flow of only an eighth of a litre per second.
The [density of oxygen at STP](https://www.engineeringtoolbox.com/oxygen-O2-density-specific-weight-temperature-pressure-d_2082.html) is about 0.04013 mol/dm3 (a little less than the equivalent [ideal gas](http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)), so we can see that our athlete needs ~5mmol of oxygen per second.
There's a single oxygen atom per water molecule. We therefore need 10mmol of water to general 5mmol of O2. The molecular weight of water is 18.01528 g/mol, therefore you can get your entire oxygen needs from .18g of pure water per second... an equivalent flow of just a 10ml per minute! (and if you're interested in checking my results [this chemistry.SE](https://chemistry.stackexchange.com/a/15879/105853) answer will help)
Obviously flow rates in a real device would likely be higher, because you don't want your electrolysis cell to go completely dry. This avoids clogging from dissolved materials like salt or calcium carbonates, and stops liberated gas from getting too hot.
You can see that you can supply all the water you need for your electrolysing-gill needs from a tiny pump, with a tiny inlet hole (or several holes to reduce the risk of blockage). Similarly, a small vent hole (or series of holes) would be needed to vent any excess gas, which will be 10mmol/s of H2 if you're directly oxygenating the diver's blood.
A resting human needs more like 5-8l/m of air, which is vastly less than the athlete, and so someone floating or paddling gently will need an order of magnitude less water.
Note: if you are generating gas to be *inhaled* you will need to split more water to provide enough hydrogen to dilute the oxygen, because breathing to high a partial pressure of oxygen results in [acute oxygen toxicity](https://en.wikipedia.org/wiki/Oxygen_toxicity) which can be fatal. This means you'll generate an excess of oxygen that will have to be vented into the sea, instead of an excess of hydrogen. Remember that whilst [hydrox](https://en.wikipedia.org/wiki/Hydrox_(breathing_gas)) is potentially dangerous under normal circumstances, you're neither generating nor storing large quantities of the stuff, and what you do generate is either consumed immediately or vented. It should let you dive safely to depths of over 200m without narcosis risks. careful decompression will still be required, but this could be made be safer and easier than [heliox](https://gue.com/blog/playing-with-fire-hydrogen-as-a-diving-gas/) diving.
**There's no need for huge surface areas for extracting water by electrolysis**.
>
> And apparently saltwater is a good conductor?
>
>
>
It is, but we've established that your electrolyser can be pretty small and hence well protected. If necessary it could be run in a pulsed mode of operation where the water being electrolysed is electrically insulated from the outside by valves, and when waste hydrogen is burped out, water can be sucked in to refill the chamber. Electroceptive species like sharks might notice your device running, but whether they'd find it interesting or unpleasant I couldn't say.
Power requirements are a slightly larger problem. Water needs [237.24 kJ/mol](https://en.wikipedia.org/wiki/Electrolysis_of_water#Thermodynamics) to split, so to split the required rate of 10mmol water per second you need a ~2380W power supply, which at the necessary [1.23v](https://en.wikipedia.org/wiki/Electrolysis_of_water) equates to a nearly 2KA current. This is equivalent to the power supply needed for welding. You'll be wanting a decent fuel cell or battery pack to drive your air supply!
Of course, a *normal* person might need as little as a tenth of the pro-athlete's flow rate, **requiring a reasonable 238W power supply**, more like an electric bicycle which is obviously acheivable with modern day battery tech without being too bulky or expensive. Even the athlete can't sustain sprinting levels of effort for long, compared to the likely length of a dive.
In any case, future fuel cells should give you pretty good energy density, and future advances in artificial photosynthesis should provide the fuel which can be conveniently made at sea on the surface.
Some further chemical cleverness will doubtless be required. For example, electrolysis of salt water can release chlorine gas which you probably don't want to breathe, and chloride ions can damage the electrolysis equipment. Some research [already exists](https://www.pnas.org/content/116/14/6624) in this area, though it is worth considering that some kinds of damage (or sabotage!) to your electolytic lungs in seawater could still cause chlorine to be released.
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[Question]
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I'm wondering if, using enough neodymium magnets (dont worry where the material is coming from) in a low martian orbit, could you produce a powerful enough magnetic field to protect the atmosphere from burning away? How would this impact interplanetary travel? How much maintenance would it take per decade?
[Answer]
If you want to protect a planet from the solar wind, the scale of the magnetic field has to be comparable with the one of the planet. A magnet, no matter how strong, has its field decay with the cube of the distance.
Magnets orbiting the planet would do little to no benefit, unless you can have a magnetic bar going from pole to pole through the planet.
] |
[Question]
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Lately, I've been looking at Google images of "centaur skeleton", but they don't look that convincing to me. The problem is whether or not the last human lumbar vertebra would be the right size to fit on the first equine thoracic vertebra as easily as clicking on a strap.
In a sci-fi horror, a mad scientist had come up with the process of "genetic bonding", in which it is possible to glue and suture at least two different bodies using only the specimens' raw genetic materials. To that end, he had cut the legs and hips off an unwitting test subject so that, through genetic bonding, he could latch his last lumbar to the first thoracic of an ungulate to create a real-live centaur. Neither bone must be too big nor too small. The fit has to be just right.
**Would this still be accomplished through a horse, or could an alternative species of ungulate have a thoracic vertebra size that is closer to the "Goldilocks plan"?**
[](https://i.stack.imgur.com/USHhU.jpg)[](https://i.stack.imgur.com/iEaTo.jpg)
[Answer]
## Summary
---
The sci-fi answer to your question is **yes**. There is a solution that involves coupling the spines and some other functions. This will work to create the first generation specimen prototypes, which the scientist can reiterate on until achieving sufficient results.
An interesting point to note is the solution, in theory, can be produced fully from biological materials. This implies that the solution can be used to **create an entirely biological race of centaurs**.
*Detailed explanation and blueprint diagram follows*.
## Spine Coupler
---
>
> To that end, he had cut the legs and hips off an unwitting test
> subject so that, through genetic bonding, he could latch his last
> lumbar to the first thoracic of an ungulate to create a real-live
> centaur. Neither bone must be too big nor too small. **The fit has to be**
> **just right.**
>
>
>
For this particular problem, we can probably assume that the mad scientist wants to pull off biologically impossible stunts, not just this once with a centaur, but with various other creatures as well.
It is most likely that these creatures will have different spine sizes (even between members of the same species), so joining most animals would be in the realm of impossibility...
Unless, of course, the scientist took inspiration from the world of plumbing:
>
> A Pipe Coupling, used in piping or plumbing, is a very short length of
> pipe or tube with either socket or female pipe threads at one or both
> ends that allows two pipes or tubes of equal or different sizes to be
> joined together.
>
>
>
[](https://i.stack.imgur.com/MGdjq.png)
Thus, the creation of the **Spine Coupler**, a thaumaturgic device capable of coupling two spines of different sizes. Each Spine Coupler has to be hand-crafted to fit the end of each ~~victim's~~ beneficiary's spine, and *plays the role of converting human nerve signals for legs, into those for the centaur's legs*.
It could convert some reproductive organ nerve signals as well, and combined with some crazy modifications to the horse's reproductive organs, or a little thaumaturgy, will allow centaur reproduction.
There remains, however, **the problem of the nerve signals for the centaur's critical organs**. The centaur's lower half would quickly die from asphyxiation as the heart and lungs fail to function without nerve signals from the brain.
## Brain Housing
---
Once the horse's head is removed, as a mad scientist, it would be a waste of materials for the horse brain to be discarded. In addition, there is also the issue of the horse's organs not being able to receive the necessary signals to function.
But what if the brain doesn't go to waste, but is used to solve this particular problem instead?
The other function of the Spine Coupler, is to house the portions of the horse's brain that is in charge of the nerve signals to the horse's organs.
One end of the Spine Coupler takes in the input from the human brain, the middle end houses a portion of the horse's brain, and the end, outputs the human leg inputs translated into horse leg inputs, as well as the necessary nerve signals for functioning of the organs.
As to the modifications necessary to make air and food holes for the horse's lungs, and digestive system, these can be looked into in another question.
## Conclusion and Diagram
---
In conclusion, with the aid of a little thaumaturgy/mad science, the mad scientist can couple the spines to route various signals from a human brain and partial horse brain to achieve the goal of combining the man and horse's nervous systems.
Although at first the human may have to take baby steps, with some horse-style rehabilitation, the human will eventually be able to learn how to control the centaur legs as his own, giving birth to the world's first realistic centaur.
Due to the coupler theoretically not needing any actual non-organic parts to create, new biological centaurs (as in, centaurs that are 100% natural) can also be created. Perhaps with the aid of some thaumaturgy and/or a mad AI to simulate the genetic sequences, the coupler can eventually be designed to be a part of the centaur's actual spinal cord, acting as a biological coupler, and allowing *centaurs to create entirely new generations autonomously*.
Prototype Diagram below:
[](https://i.stack.imgur.com/ZYfCW.png)
Link to editable diagram [here](https://viewer.diagrams.net/?highlight=0000ff&edit=_blank&layers=1&nav=1&title=Untitled%20Diagram.drawio#R7Vlbc6M2FP41flwPN3F5jL3ZeDppkxl3ZttHGRRQFyMqRGz31%2FcIxB3HzsaO7U79kHCOjgR833eOLkzM%2BXr7wHEa%2FcoCEk8MLdhOzK8Tw9B1F8E%2F6dmVHht5pSPkNFBBjWNJ%2FyHKqSlvTgOSdQIFY7GgadfpsyQhvuj4MOds0w17YXH3rikOycCx9HE89H6ngYiq99K0pmFBaBipW7tINayw%2FyPkLE%2FU%2FSaG%2BVL8yuY1rsZS8VmEA7Zpucz7iTnnjInyar2dk1hiW8FW9vu2p7V%2Bbk4ScUyH6O7pOQgeFtZyYT844vty%2BYv%2FRZH3iuOcVK9hxzDeLKCvcBnKywXjGan8cINW00g0DDfjmCYAgCB8X7cCEbGrWIBHBcLBmAFMqXT6McvhyWebiAqyTLEvnRvQIPgisY7B0uuRXgkXZLsXGL2GG2RM2JoIvoMQ1cHyFENKwZar7E1LD5pCKmpJwVFxWEkwrIduaIALxcQ7WDHtIUABqFaZjIuIhSzB8X3jnRVSJHJYDawm5pGxVIH1FxFip1IQ54J1oQS4%2BO4P2X9qoMr%2BU41XGF%2B3HWunrExgLu5kLha84SyjfuX%2BRuNq%2FABnUfF8DW%2Fyrd5mDUBgOffJG2g5qmpgHhLxRpw3rgJOYizoa%2Fc5xigtusJr4l0rIGU0EVlr5GfpaMSFdLMrLrOXpe%2BLh4vyCRpx1a%2Fy83pzBlVgka9xAq5HEsLf3wgHfAxtSUMQVDYQZ1d6BzI2E5z9IHMWM170NrXiJzULfaiQL%2B5op0ptZ4r0DqCm7gyyuyoA7eS20JmS23AvktxbKsrcRsqqMxuum8SWRpXXrYKAugVh6qEDNaGwngmnABrh11EovCMLBfpgofiYPLzLysP5KX24XXm4%2F6vjPOrwhpW6XJxpTzwsKjaG9WhVt2%2BvXrvGFHXKte3qw8WYMVKv7XMtxnR77xr5hRVTd4Os%2FXfOqoYvWZFsdxCg2%2Bm2aawWwb9HxZya0kT%2Bn7M8jTvr5XL0PQvmU5Emb6Kqgo4qW91GOwGjhud0p19thE%2FLHeHTOVeBtUb47KFbb0J2MYVM4cbhNFmVOfW4qh31%2FvApF7EkWVHTQvsYmpA0JQcUNq13MaQ0OFdMCLY%2BUdI5pqz6nazTvSFLpjMd2QTp5rlqnXk9PPXhX9MgKCbeHk2nYMN2eiUQoZH9KBopgXVdPDkVV5QyZ0Dc8aam24HcQsNNgm7Ycl%2F8iagb%2F2nU3b7OTWdkatDHdK6fDXHteiC%2FjrnB6y%2FITG3sdOxzq9FwZqjOK9Rq6tzr3VMlgW31wa2T4mLrXWtY7HvoNmvVm8XZsy6N8ntO3ssD9aNP4Bcsz2gSHnn0fjOkWe7FU2P%2FVvAjn0uqtKpaV7wff3CU3u7x8Ai3KgI09nHmc0Uwclqu0vTGZ59znrWA2XzqLL9bNN%2BTzft%2FAQ%3D%3D) should you wish to do your own mad science.
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[Question]
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So I have this idea for a creature that has a loop arch on its face. My only explanation for why is because it needs extra surface area for its sense of smell. But then I wondered what would warrant the need for so much surface area just to smell? Would dense air require it because there's more air to sort through, or thin air since they need a bigger sample size?
[Answer]
What makes a smell stronger or weaker has as much to do to do with the receptors we have as with the concentration of substances or air pressure. According to [the Wikipedia article on farts](https://en.wikipedia.org/wiki/Flatulence):
>
> Over 99% of the volume of flatus is composed of non-smelly gases.
>
>
>
By the way, there is real sciencing going on here:
>
> The remaining trace (<1% volume) compounds give flatus its smell. Historically, compounds such as indole, skatole, ammonia and short chain fatty acids were thought to cause the smell of flatus. More recent evidence proves that the major contribution to the smell of flatus comes from a combination of volatile sulfur compounds (...) These results were generated from subjects who were eating a diet high in pinto beans to stimulate flatus production
>
>
>
And also:
>
> Normal flatus volume is 476 to 1491 mL per 24 hours. This variability between individuals is greatly dependent upon diet. Similarly, the number of flatus episodes per day is variable; the normal range is given as 8–20 per day. The volume of flatus associated with each flatulence event again varies (5–375 mL).
>
>
>
An average fart of 100 mL (implying about 1 mL of smelly gases) may be easily perceived across a 360 m3 classroom. The concentration of active fart smelly gases by volume in this example is 0.00000000027%. Doubling or halving the atmospheric pressure would be equivalent to doubling or halving the area of the room, which would affect that concentration very slightly. Changing the atmospheric pressure to further extremes may not do for prolonged human life, in case you wish your creatures to live in the same world as humans.
The need to perceive smells at low concentrations will push towards more olfactory tissue area regardless of atmosphere. More olfactory tissue also allows for more varied receptors, which is why dogs are so good at identifying stuff, other dogs and people by smell. That's what you should keep in mind.
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[Question]
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Assuming real world physics and an earth-like world, how big of an area could a/some tidal mudflats cover?
Criteria-
* More or less consistently mudflats that are partially submerged at high tides
* Rock outcroppings and high/dry areas between are acceptable
[Answer]
There is an upper limit on how large mudflats can get.
This point would be reached when the height of the tides flows as far as it can, in the period between tides. Preferably without flowing in such volumes as to cause erosion of the material they are flowing over that exceeds the deposition rate. The inundation level and climate must also be such that the mudflat does not get taken over by a mangrove swamp, but remains a flat and exposed surface.
The math for this greatly exceeds me, but looking at examples from earth the deepest (greatest extend from permanent water to permanent land) mudflats seem to be some 8km from the nearest dry land, although they may be "anchored" around islands, such as the Frisian Islands of the Wadden sea, and they may border "rivers" of deeper water that penetrate the mudflats.
There is a right scholarly paper about this to be found at : <https://www.waddensea-worldheritage.org/sites/default/files/1999_mudflats-worldwide.pdf>
It lists all of the world's major mudflats and tidal flats(not quite the same thing!), criteria for their formation, wildlife statistics, and a host more.
[Answer]
[According to UNESCO](https://whc.unesco.org/en/list/1314/#:%7E:text=The%20Wadden%20Sea%20is%20the,Wadden%20Sea%20maritime%20conservation%20area.), the largest tidal mudflats on Earth is the Wadden Sea, at nearly 6,000 square miles (15,500 km) of unbroken tidal mudflats, so it wouldn't be a stretch to have one of a similar size on a different but similar planet.
[Answer]
As big as you want. With a big moon high tie could be many many feet higher so if there is a beach or plains biome and at high tide most of it will be underwater.
[Answer]
For simplicity, assume a duplicate of Earth and the moon. Actual calculations will vary depending on variation such as length of day and the length of the month, so we'll stick with Earth as an example.
The maximum width of a tidal flat, roughly speaking, can defined by the maximum tidal current multiplied by the time between high tide and low tide. Now, obviously, it's more complicated than that: among other things, the tidal current doesn't simply flow at max speed in and then max speed out, it depends on the togopraphy of the coast and the height of the tide, and so on, but it does give you an upper bound. On Earth, you get two tidal cycles per lunar day, which is 24 hours and 50 minutes, or roughly 6.2 hours from high tide to low tide. If you have a 10 knot tidal current, and a very low slope, then the maximum possible *theoretical* width would be 62 nautical miles.
However, reality has to set in: at no point will it actually get that far. The tidal current slackens and then accelerates and then falls again. Realistically, 30 nautical miles might be the theoretical maximum. But again, this all depends a lot more factors, including the period you have between tides.
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[Question]
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**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
I have a concept for a special kind of jellyfish that somewhat bears a resemblance to the generic slimes of videogames. This jellyfish was of the Cubozoa class and existed roughly 300 million years ago during the Pennsylvanian period. Sporting the same kind of advanced rhopalium as present day box jelly fish and complex nervous systems, these jellyfish evolved to expand their oxygen storage capabilities for longer than the average 48 minutes a normal jellyfish can survive on land before death. They evolved a reinforced mesoglea as well, expanding on their Cubozoan capabilities of active movement through muscular contractions to slowly drag themselves across land. (Not sure how fast.) These adaptions allowed them to traverse the swamps of the Carboniferous for one to two hours.
Early land jellyfish were detritivores, dragging themselves across swampland in order to eat. They looked like relatively flat pancakes, with tentacles splayed. Their rhopalium was incredibly advanced, able to see colour, light, etc, similar to modern day box jelly fish but even better so that they could move across land. Later on tentacles were used as collectors, dragging along detritus and passively moving it towards the jellyfish's mouth.
These jellyfish became more and more terrestrial in nature, eventually being able to store oxygen for many hours like turtles. A species of these jellyfish emerged, with even more reinforced mesoglea, enough to make it stand somewhat upright and was the size of a small baby. They had three rhopalium on their 'face', with two large ones acting as its main 'eyes' and a smaller one beneath mostly dedicated to light perception and contracting the mesoglea to become very hard. This species leaped at prey, contracting and hardening their mesoglea so that the force of impact would be enough to stun them. Eventually either body trauma or brain damage killed their prey, where they would drag themselves over and eat the prey over a long period.
Is any of this plausible and realistic? What are some prevalent issues?
[Answer]
The most obvious, prevalent issues would be moisture-retention and structural support. Not sure how to solve these though while still keeping them being recognizable jellyfish since we so few (dare I say virtually zero) working examples. The Portugese man-of-war is the only one I know of that has parts that are persistently dry and self-supported in the absence of water.
Other more insidious issues are related to inherent limitations in their morpholgy as we know it. The behaviours you describe would require very drastic changes due to these limitations. So much that you almost have free-reign so long as it doesn't seem completely unbelievable. The most immediate example that comes to my mind is the efficiency (or lack thereof) of their respiration and the apparent speed and strength limitations of their actuators, both of which are closely tied together.
Since you do not see any running, walking, or leaping molluscs, it would seem that actions such as leaping are reserved for animals that have some sort of rigid support such as vertebrates and arthropods.
For these reasons, I think the most implausible part of your description is how they somehow have the strength to leap such that their mass is sufficient to kill prey through blunt trauma. This is pretty implausible even for animals that exist today. It's a Catch-22. You need the square-cubed law so that your mass is enough that the impact is effective, but the square-cubed simultaneously limits the strength which you need launch yourself high enough. Not to mention that the predator is exposed to the same amount of deadly blunt trauma as the prey. I know of no animal that is capable of doing this, let alone one that actually does it unless predator dwarfs prey, in which case there are safer, more effective, more efficient methods.
Compare this to ramming where you can build up momentum over time which does not require huge muscles capable of a very short, powerful impulse to launch your own body weight into the air at sufficient height to cause the damage you seek. Strength like that would allow for a very deadly toss of a much smaller object at much longer range or a powerful targeted strike. And I still know of no animal that hunts with fatal ramming.
You might want to take a look at are molluscs which, like Cnidarians, are moist soft-bodied creatures which are not tetrapods, except that some members are terrestrially adapted. They might be the only real-life example you have to work off of.
[Answer]
## No
I can not find any examples of jellyfish with the ability to walk on land much less with the level of mobility you've described. But there are a few details about jellyfish biology that would suggest that they could not exist, even in the hypothetical.
Jellyfish biology is poorly adapted to life on land, even by marine organism definitions. The reason for this is that the structure of the body comes from its [mesoglea](https://en.wikipedia.org/wiki/Mesoglea). Mesoglea is a mostly acellular sac of fluid that relies on buoyancy to give it structure. Without the buoyancy of water to support it, mesoglea is not stiff enough to support the weight of the body causing it to collapse when on land. Also, bigger jellyfish tend to have higher mesoglea ratios; so, while tiny jellyfish might survive for over half an hour on land, larger ones crush under thier own weight far more easily making death almost instant. This becomes a big problem for your body slam killing mechanism if your land jellies are restricted to the size of insects.
Furthermore, its epidermis is not designed to retain water when removed from its water habitat. When a Jellyfish is removed from water it rapidly [deliquesces turning into little more than a puddle of water in a matter of hours.](http://www.beachstuff.uk/stranded_jellyfish.html) So, even if you were to expand its oxygen capacity on land, it would still die pretty quickly.
>
> Is any of this plausible and realistic?
>
>
>
Speculative evolution is not really hard science, but ... I don't really want to leave you high and dry either *(pun total intended)*. With enough time and evolution, it may be possible that a distant descendant of the jellyfish could become terrestrial, but to do this it would have to evolve a much less water permeable epidermis and a more rigid structure than mesoglea. The issue with this is that the properties that such adaptations would require would likely make the jellyfish far less slime like thereby taking away the qualities you are looking for. In general, the faster an animal moves, the more it requires a rigid body to prevent collapse under the strain of pushing itself off of things. Shy of giving the jellyfish some kind of bone like structures or lots of thick, dense muscles, its maximum mobility on land would more likely resemble that of a slug; so, if you want to make a plausible slime like creature, I would suggest nix the leaping hunter idea and go with more of an ambush hunter idea. Maybe the land-jelly stings and parallelizes passer-bys and then slowly crawls over and consumes it.
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[Question]
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The world I have imagined is much like Venus, with an atmosphere at "sea level" 70 times that of Earth, and temperatures at the same altitude approaching 377 degrees Celsius - with much more favorable temperature and pressure about 55km up. I used [an online calculator](https://keisan.casio.com/exec/system/1224562962) to find these numbers (with 55000m as ha and 20 degrees Celsius as Ta). Other than my oceans toeing the supercritical line, it seems that liquid water will exist there, and presumably evaporate and regulate the heat on the planet the same way it does on Earth.
I'm unsure how temperature and pressure effect windspeed or other weather factors. I imagine that the amount of oceans is similar to Earth, so their depth and coverage of the planet are similar. And of course, with the atmosphere so much denser the atmosphere must also extend much higher above the surface than on Earth.
**All other factors being the same as Earth: Would high pressure and heat create superstorms, or would the pressure dampen the weather towards stillness?** Please don't worry about the effects of continents and mountains (though they are present) on wind currents. I'm more specifically interested in the higher altitudes, where temperature and pressure are friendlier.
I suspect the surface is hellish enough as it is, but I'm welcome to ideas about how the weather might be at the surface. Any other ideas on how such a hot ocean might affect weather are also welcome, but not part of the question.
[Answer]
Weather gets created by differences in temperature and pressure. Why? Well, picture a cold and hot pocket of Air colliding. What happens? Well they exchange energy, trying to reach a state of equal energy. But this isn't a uniform process. Some areas cool down faster and so on. So you got this cluster♥♥♥♥ of high and low pressure, Fast and slow Winds as well as high and low Temps all around. This creates turbulence and by extension, storms, and what we call weather.
But here is the deal, you can't just increase the pressure and expect ever more violent weather. Because remember, hot air goes up, cold one goes down.
In your example, the ground could be fairly earth like in terms of wind and weather. There is so much hot air that cold one has a hard time getting there.
So what will end up happening is that you have a layer inside the atmosphere with extremely violent weather when the 2 extremes of hot air from the ground and cold air from the sky collide. And since there is so much hot and cold air, expect storms many times for extreme than on earth. But again, only for a certain layer.
If we look at Venus, we see 3 Layers.
1. "Earth". At a hight of i belive 10km or so, the Air pressure is about the same as one earth. Winds are not very strong by Venus Standarts and you would have a hard time guessing the planet you are on.
2. "Hell". This is the layer in which cold and hot air collide. This is by far the most violent Area.
3. "Hell but without the Storm". The Ground layer of Air is just sort of hot. Sure you still got winds and Lightning and its generally not a good time but in terms of Weather, its fairly chill.
To close out, the Weather on the Surface would mostly just be hot with some Winds. How strong the winds are depends on a lot of stuff. But i would say not stronger then on earth. Again, there is only hot air, so no storms.
But I would have an idea on how to make to story more interesting. Lock the planet's Rotation. If the Planet is Locked, you got a Transition zone from Day to night side. This would create ultra violent weather, as all the cold air from one side of the planet collides with the hot air from the other side. This transition zone might be worse than Jupiter.
You could even make something like this: the planet isn't locked to the Sun, the rotation is just very slow. Meaning you got this Jupiter Storm System raging across the planet.
[Answer]
TL;DR: If you want interesting weather, make it spin very fast.
Most of Earth's weather (and I think Jupiter's too) is due to [baroclinic instability](https://en.wikipedia.org/wiki/Baroclinity#Baroclinic_instability) within the atmosphere and oceans.
Differential heating -- more direct sunlight at the equator than at the poles -- is part of the effect but not all.
You could have a planetary atmosphere with very strong differential heating but for which the atmosphere efficiently transports this heat to the poles, which would equilibrate and become kind of uninteresting.
Venus's atmosphere, while very inhospitable and which has permanent jets, doesn't have dynamics quite like Earth or Jupiter because it doesn't rotate fast enough.
The rapid rotation relative to typical flow speeds within the atmosphere can be summed up in a dimensionless number called the [Rossby number](https://en.wikipedia.org/wiki/Rossby_number).
For example the Great Red Spot of Jupiter has a Rossby number around 0.01.
If you want to read more, [this paper](https://www.lpl.arizona.edu/%7Eshowman/publications/showman-etal-2010-exoplanet-review-official.pdf) is a nice review of exoplanetary atmospheres.
You asked about high pressure specifically.
Deep down in Jupiter's atmosphere, the pressures are absolutely gigantic.
I think there's still some debate as to whether Jupiter's weather is confined to a thin layer near the top of the atmosphere or whether there's interesting dynamics below, with a slight lean towards the second case according to some simulations of Jupiter's climate.
In any case, it's perfectly plausible to imagine a planet with an atmosphere that's under much higher pressure than Earth and which still has interesting weather.
[Answer]
On Venus, though it is very calm at the surface, the air is so dense, that even a gentle breeze would push you along like a sail
-David Aguilar, in Space Encyclopaedia.
Pressure matters. You can just push a person with a gentle breeze if the ambient pressure is more than 50-60 bars, whereas you would need extremely strong winds to cause a modest dust storm with low ambient pressure (BTW, Martian dust storms are mostly caused by electrostatic repulsion and rising thermals, in which strong winds are a just a catalyst as the air pressure is too low to lift dust)
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[Question]
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**This question already has an answer here**:
[How would falling buildings affect the earth?](/questions/154574/how-would-falling-buildings-affect-the-earth)
(1 answer)
Closed 3 years ago.
So basically, there’s this giant floating island with a whole kingdom built on it. When the magic that’s holding it up fails, it hits the ground (middle of the ocean) at a high speed. The actual story is set a few thousand years after this, so I’m not worried about the cataclysmic tidal wave from this. I can’t figure out what the actual buildings would look like after being dropped. Would they be entirely removed from their foundations, or just collapsed?
**Edit**: more information: The island had a medieval-style kingdom built on it. It was built with lots of stone bricks, as well as wood. The island dropped straight down in free fall when magic stopped working all at once.
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So, there are two main loading conditions you need to consider when it hits the water: horizontal and vertical. Both are common on Earth in earthquakes: the horizontal earthquakes are commonly caused by strike-slip faults (like San Andreas), and the vertical earthquakes are caused by normal/reverse faults (like Chile). [1](https://en.wikipedia.org/wiki/Earthquake) A horizontal earthquake can, if conditions are right, just move buildings like that magic trick of pulling out a tablecloth from under a bunch of dishes. They are usually not as damaging, but if your island is just falling straight down, the horizontal shaking is likely to be minimal.
The vertical forces, on the other hand, are likely to be much greater. Extreme earthquakes can result in forces as high as 3-5g.[2](https://en.wikipedia.org/wiki/Peak_ground_acceleration) If your island is massive enough, it might be able to slow down slowly enough to stay around that force.
However, that tidal wave... after the initial "sploosh" out, there will also be a tidal wave coming back into the city. This tidal wave will likely destroy most of your city. For an example, see this high-speed footage: [youtube](https://www.youtube.com/watch?v=pLL6oseE5_U)
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There are three main languages in this world:
* **Draconic**, used by the "old" races, i.e: tengu, dragons, lizardfolk, etc...
* **Abyssal**, used by both demons and angels: Initially was a low-level language where the description of basic concepts could fill books. Later, a renowned demon collected the most common concepts and structures in the language into libraries and assigned shorthands for them. Nowadays, the language diverged into several dialects:
+ ***Structured Query***, used to organize data.
+ ***Object-oriented***, used to describe various complex systems by breaking them down to their components (objects) which have attributes and functions (things they do).
+ ***Linear***, somewhat deprecated but makes the description of linear (from point A to point B without side-roads) processes easier.
* **Common**: British English, the isekai gang had brought in.
Common is the language spoken.
A name's meaning comes from the draconic word(s) it was made from.
Abyssal is used in magical incantations.
So, I managed to avoid having to create multiple fleshed-out languages. Yet, I don't know what to do with this one. You see, this language is supposed to accommodate the dialects of quite a few races. Tengu put in clicks and trills to convey simple messages (like ridicule), lizardfolk might hiss, dragons could roar, draconic simply connects these together with a "common ground". Since it's also used to name people and places, it has to be present in a spoken and written format, the latter with both a runic (used for marks and carvings) and a "formal" alphabet.
So, one extremely complex language. Great.
I have no idea how to start with this one most ~~gulagers~~ conlangers limit their phonetic inventory, I'm using Hungarian for the "standard", plus the tengu/dragon/snake/monitor lizard/[programmer](https://www.youtube.com/watch?v=TZ7t304R4Xg) noises, though they're usually undertones. I have to, as tengu want names with lots of front vowels (*e, é, i, í, ö, ő* and maybe even *á*), lizardfolk, and dragons probably want mixed/neutral ones for themselves and demons want `sudo rm -rf /home/` and similar curses as their identifiers.
So, yes. This is the problem, draconic is supposed to accommodate a lot, which makes implementing phonological constraints much more difficult. **The language is supposed to have a "character", how can I ensure that without limiting the races' own dialects and unique words?**
To be clear, the language is primarily a conlang, similar in purpose to Esperanto, though **I mostly want it to be a basis for names**. The main difference is that I mostly use Hungarian grammar rules as they manage to remain somewhat sane without compromising the language's capabilities.
I mean, "Say it as written" is a fundamental principle with the most striking exceptions being legacy stuff, i.e: old family names Like Kossuth (Kosút) and Dessewfy (Dezsőfi); and "mistakes" you make naturally dió -> dijó. So, a Hungarian spelling contest would make little sense.
Hungarian is also an agglutinating language, so Megszentségteleníthetetlenségeskedéseitekért, is a valid word, though a tad bit nonsensical.
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What are your objectives here? What *use* are you planning to make of the world you're constructing? The more you're going to expose your worldbuilding to criticism, the more work you're going to have to do. To pick some arbitary categories:
* If you're trying to write a really good fantasy novel that makes a big thing of languages, you're going to have to learn a lot about phonetics and language construction in general. There are very few novels or series that have impressive linguistics. The main example is the Tolkien legendarium, and he was a Oxford professor of English, specialising in philology. Trying to match his standards is beyond most people.
* If you're trying to write a less ambitious novel, or doing a RPG setting, simply using Hungarian as your draconic language is a reasonable idea. It worked for Steven Brust, after all. J K Rowling used dog-Latin as her magical language, which works for story purposes, partly because Latin was a common subject of study in the school stories she was riffing off. If you want something with more fluidity of expression than Latin or Hungarian, Ancient Greek is a good choice, and there are lots of dictionaries and translation sites on the web.
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Honestly, your best bet here, if you want "Draconic" to be a single language, are Accents and Dialects.
Taking Accents as the first example: Compare a thick Glaswegian brogue, such as on display in [Taggart](https://en.wikipedia.org/wiki/Taggart) with, well, [James Bond](https://en.wikipedia.org/wiki/List_of_James_Bond_films). It's the *same language*, but the phonemes (of which English only has 44!) are being said astonishingly differently. Jokes abound that some people need subtitles to make sense of the former.
c
Just because Tengu, Dragons, and Lizardfolk have the same basic language, doesn't mean that it's easy for them to understand each other. The underlying sounds may be *roughly* the same, but the accent will tend to "hiss", "growl" or "chirp", based on the vocal organs available to them. (Similar to how [tounge-tie](https://en.wikipedia.org/wiki/Ankyloglossia) causes a lisp)
On the 'Dialects' front, the best real-world example we have is the ['Chinese Language'](https://en.wikipedia.org/wiki/Chinese_language), which really only exists in the written form. For speaking, you have [Mandarin](https://en.wikipedia.org/wiki/Mandarin_Chinese), [Cantonese](https://en.wikipedia.org/wiki/Cantonese), [Hu Dialect](https://en.wikipedia.org/wiki/Shanghainese), and [many more](https://en.wikipedia.org/wiki/Languages_of_China). People from one part of China may be unable to understand what people from *other* parts of China are saying - but they [read and write](https://en.wikipedia.org/wiki/Chinese_language#Writing_system) the same symbols. For example, the character "一" (which translates into English as "1", pronounced "one") will be pronounced as "yī" in Mandarin, "yat" in Cantonese, or "yet" in Hu Dialect. "Hello", written "你好" is "Nǐ hǎo" in Mandarin, "néih hóu" in Cantonese, or "nóng hō" in Hu Dialect.
(This was quite a clever ploy by the Chinese Emperor, providing a way to disseminate his edicts and laws in a way that any of his subjects could understand them, without trying to force them to learn an entirely new spoken language. Part of the reason for its success is, of course, that the spoken languages are all members of the same 'family', so their syntax and grammar are sufficiently close to be covered by a single pictographic writing system.)
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An area of my planet is *very* saturated with lava. Being quite similar to the [Siberian Lava Traps](https://www.google.com.ph/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwiWwcyKk9PoAhWGwpQKHfRjAZoQFjAHegQIDRAF&url=https%3A%2F%2Fwww.le.ac.uk%2Fgl%2Fads%2FSiberianTraps%2FIntroduction.html&usg=AOvVaw3MaTin0GoetD5qQGkeG7_7), it is essentially a lava sea. This lava “sea” area isn’t necessarily all lava however, as there are actually some rocky islands dotted about the sea.
Life, always finding a way, has seeded themselves on these islands. They’ve even achieved sentience. Being incredibly heatproof however, costed them their looks, the other sentient races labeling them “demons”. They’re quite nice though, just misunderstood.
For some reason, the lava doesn’t emit any greenhouse gases nor does it emit gases not conducive to life. That’s why the rest of the planet is very Earth-like. Only being near to that area would you start to feel the heat.
Is there any rock or metal that this molten sea should be composed out of, so that it won’t emit greenhouse and poisonous gases?
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tl;dr
Pick one, not two:
1. Small ephemeral lava flows, and no persistent wide lava "seas". Habitable planet.
2. Large persistent lava seas. Inhabitable planet.
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Lava, by definition, is molten rock at the surface. Taking that limited definition, there is no problem being around lava, more than being around molten chocolate is more dangerous compared to solid chocolate. People stand just next to Hawaiian lava flows all the time.
The problem is that it's very hot. You obviously don't want to touch the lava, or stand too close.
Lava does not necessarily have toxic gases. The most abundant volcanic gas is H2O, which is dangerous when at several hundreds of degrees, but rather nice when liquid. Some lavas contain gases like carbon dioxide, hydrogen sulfide or sulfur dioxide, but not all. Another interesting fact is that once on the surface, the gas bubbles away very rapidly. So you can imagine a volcano erupting lava flows, and by the time the flows reach the bottom, several hundreds of metres away, they have already degassed and quite safe to stand next to.
Your problem is not the necessarily the toxic gas. It's keeping the lava liquid. Lava tends to solidify very fast. It quickly forms a solid crust on the top where in contact with the much colder atmosphere, and then lava flows underneath in lava tubes. The top of the lava tubes is usually very hot and brittle, not a place suitable for life. And once the lava reaches its destination, it again solidifies in a matter of hours to days. It can remain too hot to the touch for days to weeks, though.
You suggest that you can just keep erupting more and more lava ("replenish the lava seas"), but that lava has to go somewhere. It will just fill up the lower areas, then solidify, then form more and more layers on top, burying whatever is there.
If you want your lavas to stay liquid for very long (years? decades?), they need to erupt into an environment which is hot. Think something like the surface of Venus. Your planet as a whole needs to be very hot, and it gets very hard to sustain life as we know it on a planet like this.
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Well lets look at what normal lava is made of. [Here](http://volcano.oregonstate.edu/what-lava-made) it says it has silicon, oxygen, aluminum, iron, magnesium, calcium, sodium, potassium, phosphorus, and titanium.
[Here](https://volcanoes.usgs.gov/vhp/gas.html)it says some gases it emits that are dangerous include CO2, SO2, H2S and Hydrogen halides. So let's make your lava sulfurless and have a lower concentration of hydrogen and halogens. That's all you need to do to make the lava not give off poison.
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My temple was built near a kaolin surface mine, which is itself topping an old deep mine (where they used to mine radioactive metals, rare earths and possibly other miscellaneous, if need be). This temple was so beautiful that one day the gods took it to heaven, i.e. fell down a sinkhole/big mine shaft (it doesn't matter which) that opened/reopened under it. My MC descends through the mine to investigate the temple, which was sealed in kaolin since the day it fell down.
1) What toxic gases can there be besides CO2? There is no coal.
2) Is this setup geologically passable? If not, what should I tweak?
I can tweak the conditions, and I'm not aiming for 100% accuracy. I'm going for *passable* in case an expert stumbles upon it.
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Disclaimer: IANAG(eologist)
Most of the [radioactive](https://en.wikipedia.org/wiki/Uranium_ore)/[rare-earth](https://en.wikipedia.org/wiki/Rare-earth_mineral) that I saw are present in the form of silicates, hydroxides, oxides, phosphates, carbonates, borosilicates, vanadates. Haven't seen any in the forms of sulfides or arsenides. So probably no chemically toxic gases.
[Radon](https://en.wikipedia.org/wiki/Radon) has a half-life of only 3.8 days, you'd need a lot of uranium/thorium around to get a high enough concentration of radon (in which case, radon is likely the least of your problems)
If the mines are no longer operating, the particulate suspension in the air is going to be low. At the best, such exposures may occur if your character causes a collapse of some dust heaps (assuming dry dust accumulations)
I'd be more worried about exposures to water leeching the rare-earth/radioactive ores around and pooling them in concentrated slurries here and there.
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Addressing: `why the area is not flooded`
[kaolinite](https://en.wikipedia.org/wiki/Kaolinite#Synthesis_and_genesis) does *not* evolve in *always damp* conditions
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> While studying soil formation on a basaltic rock in Kivu (Zaïre), they noted how the occurrence of kaolinite depended on the "degrée de drainage" of the area involved. A clear distinction was found between areas with good drainage (i.e., areas with a marked difference between wet and dry seasons) and those areas with poor drainage (i.e., perennially swampy areas). Only in the areas with distinct seasonal alternations between wet and dry was kaolinite found. The possible significance of alternating wet and dry conditions on the transition of allophane into kaolinite has been stressed by Tamura and Jackson (1953).[31](https://doi.org/10.1126%2Fscience.117.3041.381) The role of alternations between wetting and drying on the formation of kaolinite has also been noted by Moore (1964).[32](https://doi.org/10.1180%2Fclaymin.1964.005.31.02)
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One *can plausibly* assume the kaolin deposit was draining through cracks into the bedrock, so there will be at least seasonal opportunities to descend into the old mine galleries.
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Here a laser raptor Pew Pew'ing in its natural habitat and timeline.
[](https://i.stack.imgur.com/OWMMs.gif)
[](https://i.stack.imgur.com/euNda.jpg)
(From the [Kung Fury](https://www.youtube.com/watch?v=bS5P_LAqiVg) movie)
So I want to know how a biological organism can develop to spew laser beams through their eyes. What kind of organs are needed to generate the laser, and are the natural adaptations required to achieve this?
The laser eyes's function is not like Cyclop's from the X-men, but more like laser beams from Superman's eyes where you can switch it off and on.
Preferably they would still have functional eyes to see normally, so no ecolocation, x-ray vision, etc
And as I mention the eyes should be biological and natural, so no genetic engineering or bionic technology involved.
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[It may surprise you to learn that is possible to generate coherent light using a biological medium as the material](https://www.nature.com/articles/nphoton.2011.99). Bioluminescence and reflective coating (for the inside of the cell) are at least part of the requirements, that I've been able to figure out.
### The Problems
This is very weak. The abstract of the paper I linked mentioned using the technique to image a cell by having it emit a laser. Any small amount objects, like proteins or organelles, will cause diffraction and absorb some energy.
And that leads into the real problem with using an eyes for a laser: It will cook itself. The laser emitter is going to generate waste heat. This is proportional to the energy of the beam. 30% efficiency is considered high for a laser. For every joule of power delivered to the target, at least two are going to dumped into the eye. And that's with pure materials, measured construction, and and ideal mechanism.
In addition, the efficiency of the laser is probably going to tank as it heats up and cooks itself, so that's another problem.
And while the eye isn't the worst shape for a laser (presuming you use the entire retina as the emitter) the problem is that with the small aperture you won't be able to focus the laser onto a small spot. To get around this, you could pump up the power, but your laser is made of the same stuff as the target. If it would burn human skin, the laser eye would probably be burning itself. Remember, 30% efficiency is high for a laser.
As far as actually seeing through this eye, it would be possible, but optical systems are reversible. The field of view would be incredibly "zoomed in" so this eye would only be useful for precisely aiming that laser. It would be like running around with a pair of telescopes glued to your eyes - no peripheral vision at all.
### So, how will we make this work?
This absolutely would not work without genetic engineering, though. The first steps toward a laser eye are useless. The first steps toward a normal eye are not.
This eye is going to be massive. Like a satellite dish, almost. The bigger, the better. This makes it easier to get a small spot size on the target and means each bit of laser-retina needs to output less power. On the back, there will be some sort of cooling mechanism for the blood leaving the laser-eye. There may need to be circulation and cooling, and filtering of the interocular fluid as well. This is going to need a lot of blood flow and food to fire.
The rest of the body must be designed around this laser. Storage of energy in some form to quickly refuel the retina after each firing would be needed. You'd also need secondary eyes for peripheral vision as well, like how snipers work with spotters. Not to mention the actual physical support of this laser as well. If you think your neck gets sore holding up your head, imagine how bad it would be like this.
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This is a follow up question to: [How realistic is the Swampus?](https://worldbuilding.stackexchange.com/questions/166100/how-realistic-is-the-swampus)
What adaptations would current octopus have to evolve, to become land based, meaning that they spend at least 1/3 of their time on land?
How long would the development of such features take, and can you come up with a scenario, that makes land based cephalopods plausible?
Helpful traits I came up with:
1. leathery skin, so they don't dry out in the sun
2. ability to breath air, similar to lung fish?
3. the redevelopment of their internal shell to support land based movement
4. development of a joint based internal shell in their arms, to support movement
5. improved camouflage abilities to avoid faster predators
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**A method of controling the osmolarity of their bodies**
One of the big challenges in moving on land is dealing with osmotic balance (how salty the internal environment of the cells in the body is). Most organisms have internal cell contents that are quite salty, but maintaining a consistent salinity level is necessary for survival and proper metabolism.
A lot of terrestrial organisms are thought to have moved into fresh or brackish water before moving onto land, and even if you do go straight from marine waters to land if you want to go inland you have to deal with every reliable source of water potentially being too dangerous to drink. Saltwater animals retain freshwater and excrete high amounts of salts. Freshwater animals absorb salt through their gills and excrete a lot of water. It is possible to do both, but you have to be able to regulate your internal salinity and it is hard (as evidenced by the rarity of salt-and-freshwater tolerant fish rather than just salt or just freshwater).
[Most cephalopod species are osmoconformers](https://www.academia.edu/9393419/Transitions_during_cephalopod_life_history_the_role_of_habitat_environment_functional_morphology_and_behaviour), and are stenohaline, which means they mostly keep their body salinity at the same level as the surrounding saltwater and really don't like it when the salinity changes. Kind of like sharks to some degree. A giant squid or a Humboldt squid could get large enough to simply ignore salinity changes for short periods of time due to osmological inertia, but large cephalopods generally don't live close to estuaries. A Pacific giant octopus might be able to handle it, [and there are apparently reports of this happening](https://southofultimathule.wordpress.com/2011/08/18/alaskanoctopus/), but given that is self-reported on the internet I would take it with a grain of salt.
The first step to putting a cephalopod on land would be to give them a system of osmoregulation they can use to tolerate the more osmologically varied environements of tide pools, estuaries, and rivers. This isn't impossible probably, fishes have done it and at least two other groups of mollusks have colonized freshwatr (clams and gastropods), and notably gastropods then went on to colonize land (though I'm not sure how well they osmoregulate given the whole salt thing). Notably, there are no freshwater cephalopods and as far as we know there never have been in the fossil record, though a couple of species tolerate brackish water.
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I made an organism called the [Skarlix](https://sagan4.miraheze.org/wiki/Skarlix) for a art/xenobiology project called Sagan 4.
The Skarlix is a eukaryotic, somewhat amoeba-like organism that "eats" various metal compounds and "breathes" (oxidizes) hydrogen (e.g., in the form of hydrogen gas, unless other compounds are more plausible). Its metabolism is based partly on the brief Wikipedia description for knallgas bacteria. However, I think I messed up at some point in its description, probably because I didn't understand the difference between "eating" and "breathing" at the molecular level.
I think "eating", on the cellular level, means gaining energy for growth. Is there a way to make it gain mass by eating metal compounds of some sort, but use hydrogen in roughly the same ways human cells use oxygen? If not, is there a way to make it need very little to no oxygen, "breathe" an alternative element or chemical, and rely on metal in sediment?
More information: This is a free-living, somewhat amoeba-like (in shape) simple eukaryote which lives in sediment in the ocean. While I don't need to go into detail on electron donors and acceptors in its description, I do need to know whether this metabolic combination is even plausible. If not, I should alter it. Ideally, any alteration wouldn't prohibit its descendants from plausibly living in the guts of a creature that consumes very iron-rich foodstuffs, or within the blood of a creature with manganese-based blood.
The Skarlix was created in an era equivalent to the Precambrian/Early Cambrian on its planet, after a big extinction event. Since it was created, many microbes have developed, probably including those that make hydrogen compounds. While pairing it with a microbe that consumes hydrogen makes sense, that's going much too far into its timeline to be plausible. As for its diet of "metals", that was left unspecified in the description. Early lithotrophs in the Sagan 4 project didn't have their exact diets specified, presumably so even people unfamiliar with lithotrophic biochemistry could stock the planet with lithotrophs. Any metal which makes sense in this situation is appropriate, except copper, which I specified is too poisonous to it. (not sure about the plausibility of that, but it's stuck there. Another organism was later developed which ate copper, an under-utilized resource because the Skarlix wouldn't eat it.)
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We breath oxygen primarily because it's highly electronegative and hence works as an electron attractor in the electron transport chain system of atp production. This is a rather specific metabolic system and it's far from foundational, tons and tons of bacteria don't have this type of energy system, (in fact even humans have several others in addition to this one!)
In fact, there are really existing earth bacteria that use metals in their metabolic systems, and frequently absorb environmental sulfur or oxygen (or probably other things, maybe not hydrogen though, H2 is very stable) as a way of breaking down metals into more usable forms.
Really you've just got to decide how detailed you want to get with this. Fully describing the chemistry of a totally novel metabolic cycle seems like it would be pretty hard, certainly it's above my pay grade. At the same time, I wouldn't doubt for a second the plausibility of "a Bacteria which metabolizes [some metal] by absorbing [some gas] in a low oxygen atmosphere". Hell, there's probably one on Earth that fits the bill.
To fill out this response with some more specific information, you can look at a couple of the following things:
1: Sulfate Reducing Microorganisms: <https://en.wikipedia.org/wiki/Sulfate-reducing_microorganisms> -- these are examples of bacteria that "breath" sulfates instead of oxygen to power their respiration. In other words, they use sulfates as the final electron acceptor in their electron transport chain. These are prokaryotes however. Some of these are called Chemolithoheterotrophs, which is the class of bacteria here that reduces inorganic material rather than organic material, which is kind of the thing you are looking for.
2. <https://microbewiki.kenyon.edu/index.php/Dissimilatory_metal_reduction>
Here is a short article talking about how microbes can "consume" metals to produce energy. In your post you said you wanted the microbe to consume metals to gain mass, but keep in mind that for the most part the mass of a single microbe is naturally limited by scaling factor difference between volume (~mass) and surface area (~max "eating" rate), so for a colony of bacteria to gain mass by consuming metals you just need a metal to be "consumed" (usually this means corroded or oxidized) as part of the colony's metabolic process.
I'd hoped to find an example of a specific Earth bacteria fitting your criterion, but I wasn't able. However, nothing about what you're asking for is too 'out of this world' (yuk-yuk) certainly the individual elements you're asking for are well represented and pretty well understood.
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Let's take a look at what the living things we know do.
They breath in oxygen, combine it with carbon from their diet, then exhale carbon dioxide.
The chemical reaction of 2 parts of oxygen with 1 part of carbon is an exothermic one.
Which means that the process releases energy and that is why we are able to rely on it in the first place.
Now let's take a look at what you want to accomplish. A microbe that uses some metal + h2 to create a new molecule and gain energy in that process.
So the question can be rephrased to: Is there a metal that when combined with h2 produces an exothermic reaction?
Now unfortunately my chemistry knowledge is miserable. But maybe someone else can come up with an exothermic reaction of h2 and some metal.
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I had an idea for a new world that included cactus forests, with cactuses the size of a giant sequoia. Is this realistic?
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Both the [Saguaro](https://www.nps.gov/orpi/learn/nature/saguaro-cactus.htm) and the [Giant Cardon cacti](https://arizonadailyindependent.com/2016/05/15/mexican-cardon-cactus-the-worlds-largest-cactus/) can reach 60 to 80 feet in height ... 1/4 the height of a mature sequoia. It's thus plausible to think that, in world with lower gravity than earth and fewer competitors for the cacti, they could reach over 200 feet high (sorry, don't have the math to say how low).
The lower gravity would be important; the main reason the saguaro is so tall is to hoard water while not increasing sun exposure the way a round body would (see the first link for this). This would also suggest that a longer period between rainy seasons would make saguaro-like cacti likely to grow taller.
So, if you want sequoia-tall cacti, you want a world with lower-that-earth gravity, and a large arid continent with hot sun where it rains heavily every 2-3 earth years, but very little otherwise.
What this *doesn't* get you is a dense forest of 200ft cacti. The water-hoarding cycle of large cacti requires them to be spaced pretty far apart, so that each plant can gather as much moisture as possible.
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**Pyramid plant.**
Tall trees have been done. But what about a cactus tree that is as wide as it is tall? A pyramid cactus?
Some dry adapted plants are nearly as wide as they are tall. The baobab tree is one.
<https://kate-pickering.com/phd-research-blog/2018/6/4/the-fat-trunk-of-the-baobab-tree>
[](https://i.stack.imgur.com/22cjV.jpg)
Minimizing surface area is a fine strategy for dry-adapted plants and there are lots of cactus that are barrel shaped or nearly spherical.
Your giant cactus would take this to the extreme - a colossal wide trunk slowly tapering up to the top. Most of this internal volume is occupied by water kept in gel phase, cactus style. The cactus trees might cheat, tending to grow adjacent to rocks which capture rain and dew and let it run off to the tree. As the tree grows adjacent rocks are used for support.
In the desert, these cactus trees have no competition for sunlight\*. They are so large because its water volume must sustain it through prolonged dry periods. The great pyramid trees shrink and wrinkle during these dry times.
Giant green living pyramids in the desert wastes would be pretty cool for a fiction. As opposed to living on top of these "trees" the inhabitants would live inside burrows that they excavate within the living tree. I could imagine the tree might be OK with animal life - nitrogen and phosphorus can be hard to come by as well. If you are the desert's master waterhoarders, you can trade a little of your hoard in exchange for nutrients that the animals bring you in the form of their wastes, and eventually their bodies.
\* I wonder why the saguaro cacti get so tall. They have no competition for sunlight either.
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Some advanced human civilization built a large, 6,000 km diameter [gravity balloon](http://www.scifiideas.com/science-2/colonizing-asteroid-cores/) and filled it with a breathable atmosphere as well as small, rocky bodies with radii of ~200 meters and masses of ~$6 \times 10^{15}$ kg. This was accomplished via **mumbling about [strangelets](https://en.wikipedia.org/wiki/Strangelet)**, giving these small pseudo-planets a surface gravity comparable to that of the earth. At various points along the walls, sunlight is directed inside via co-orbiting mirrors. A 24-hour day/night cycle is simulated by manipulating these mirrors.
Though the outside world is very advanced, the people who built this decided that they would only permit the residents to use technology up to that of about the 15$^\text{th}$ century and are willing to enforce this with force, if need be. As a result, the population lives in a perpetual medieval stasis and knowledge of high technology has been lost.
I'd like these people to be able to travel between their little planets. However, I'm a bit stuck as to how they might go about this given their medieval technology. In particular, I'm wondering
1. How can they get off of their planets?
2. What sort of craft would they use to travel between planets?
I'm not entirely sure what sorts of air currents would exist in this world, but if it helps your answer you might assume that some sort of convection currents move in and out of the regions where the sun shines through the wall.
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Major nitpick: you've got a habitat that's *6000km* across, presumably with a conventionally earth-density-and-pressure-and mix atmosphere in it. From the centre ofthe habitat, you're looking through 3000km of air. On earth at standard temperature and pressure, a square metre of surface has about 10.3 tonnes of air pressing down on it. A cuboid of air 3000km long has more like 3675 tonnes of air in it. Even totally clean air without a trace of haze, dust or cloud is not *perfectly* transparent... various optical effects conspire to reduce its transparency. On Earth, looking straight up, the air mass above you will consume about [14%](https://www.skyandtelescope.com/astronomy-resources/transparency-and-atmospheric-extinction/) of the intensity of incoming light, or .16 [magnitudes](https://en.wikipedia.org/wiki/Magnitude_(astronomy)). Lazily using the same equation (proper calculation of absorption and scattering seems like too much hard work right now) it suggests that the centre of your habitat will see a *57 magnitude attenuation in sunlight intensity*. Our sun as seen from Earth has an apparent magnitude of -26.74. Its effective magnitude in the middle of the habitat will therefore be 30, which is so faint that you need something like the Hubble Space Telescope to see it.
Most of your worlds therefore will be clustered around the walls of the habitat, and the further they drift from it the darker and redder the light will get until you descend into the black depths.
There will be some weird effects to do with air density being higher around the worlds, of course, and more problematic issues with worlds being gravitationally attracted to each other which will make them all glom together over a long enough timescale. I won't worry about those things here, but you might do well to consider them.
I suggest you have a read of [Engineering Virga](https://www.kschroeder.com/my-books/sun-of-suns/engineering-virga), a discussion of the nature of a hollow air-filled habitat that is more like 8000km across. It too is filled with small habitats, but they spin to provide their own gravity (and so the issue of mutual gravitational attraction is avoided), and there are artificial light and heat sources that habitats are clustered around (and so the issue of light extinction is avoided). The article is interesting even if you don't bother reading the stories associated with it.
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But now lets turn to your actual questions.
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> How can they get off of their planets?
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You might be able to fling *some* stuff into the void mechanically... the escape velocity of these worlds is only 62.6m/s, which is faster than a sling will fire a bullet but a lot slower than a decent crossbow (which could manage >90m/s even with medieval technology). I'm not going to do any drag calculations to see if the bolt would in fact escape, but the possibility does exist. Note that this means that projectile weapons should be used with *extreme caution* as you could throw or fire projectiles right around the world and shoot yourself in the back. Projectile weapon tactics are likely to be *interesting* on these worlds. Incidentally, I wouldn't want to launch a ship this way as accelerations will likely be neck-breaking.
The most sensible way though would be with a ladder (or a tower). If you travel upwards by $200\sqrt{2}$m (about 283m), the force of gravity will be reduced by half. Each time you extend your ladder's length (or tower's height) by a factor of $\sqrt{2}$, gravity will halve again. Building a tower into space will be tricky, and a lot of effort, but not impossible by any means (assuming there was enough material available). It'd be nice if the builders of the habitat had conveniently provided such things for you, of course.
Orbital velocity at the top of a 283m tower is 22.6m/s. This means that with a relatively streamlined aircraft and a fit pilot you might be able to drive your crank-driven prop-plane into an orbit, and from there you may even be able to raise your altitude yet further until you escape. You might even be able to build a little catapult to get you started. Launching larger craft with more passengers or cargo sounds like a stressful exercise, however. Orbital velocity is inversely proportional to the square-root of the radius, so to halve the velocity required for orbit you need a ladder or tower that reaches up four times as high. This starts getting into the realms of multiple-km high towers that will almost certainly need to be provided by the creators of the habitat, though.
One could tether two worlds together and climb along the framework between them, if the worlds weren't spinning. If they were spinning, you could make a space elevator... the worlds are so small that you could use some fairly simple materials of the sort that would be available with medieval tech (such as silk).
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> What sort of craft would they use to travel between planets?
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Flying around in the void would be easy... a loose framework of sticks and cords would do, with suitable flappy bits (or even propellors... windmills existed back then, after all) and rigging to allow them to be operated by a person. Takeoff with such a craft would be *extremely* difficult unless you have a very, very tall tower (many kilometres high) so you'll need something much more aerodynamic to get you started. Once you've done that though, you have a means to haul stuff up into space and maybe build yourself a space elevator or staging space station and later flights (and dedicated microgravity aircraft) become much easier.
For landing, you want to be a little bit careful... terminal velocity is likely to be less than for earth, but it will still likely be terminal. Use a parachute, autogyro or glider to control your descent. Docking at a space station would perhaps be simplest.
The biggest problems here, I think, will be the bearings and mechanisms used to drive the fins or props for your aircraft. They'll need to be compact, light and efficient or you'll never be able to go fast enough. You'll either have to have slightly anachronistic machining capabilities, or the builders of the habitat will have to provide space towers. You get to decide which, of course.
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*edit*:
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> technology up to that of about the 15th century
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Ah-**hah**.
I missed this the first time around but: by the time of the 1400s, gunpowder weapons had been in existence for [at least 500 years](https://en.wikipedia.org/wiki/Timeline_of_the_gunpowder_age). Sure, fire-arrows, fire-lances and bombs aren't *immediately* useful, but again: but the time of the 1400s, *military rockets had existed for over 150 years*.
Usually when people say they want a medieval technology restriction they forget this sort of stuff, but remember the wise words of Gibson, "*the future is already here - it's just not evenly distributed*". It could easily be very rare in your environment... it'll be difficult to mine nuclear density matter and do anything useful with it using medieval technology, after all, but a gunpowder [Rocket-Assisted Take Off Gear](https://en.wikipedia.org/wiki/JATO) would definately be a way to get your ships offworld.
[Answer]
We really need more information concerning the nature of your world, I fear that air resistance would destroy your world in short order. But I will attempt an answer.
Given the situation I would assume that your “medieval” is not going to be an exact mirror image of classic Earth medieval since they will be flying between worlds, but it just means primitive pre steam engine technology.
Problem number one: getting off their worlds. It all depends on how gravity works here if gravity falls off quickly with altitude they might well be able to build a very high tower as tall as a cathedral spire or more and use a ballista or catapult to launch into orbit.
Problem two: propulsion. With up to 6000km to travel any journey is going to be exceedingly slow and hazardous. Air currents might well be used with large wing like sails to increase or decrease the surface area in contact with the currents and also being capable of being moved like oars by the crew to manoeuvre when away from currents or nearing the other planets.
Problem three: landing. This could be very hazardous! They should not approach too close too quickly or gravity would pull them down in the wrong place. They would have to spend a lot of time manoeuvring at just the right height and might hope to be caught in some form of high level netting attached to the tall launch spires.
[Answer]
You could potentially build a hot air balloon with medieval level tech. This would only get you to a certain height above your pseudoplanet since it does require gravity to provide lift. After you reach a height where gravity is negligible you could use wind currents or propellers similar to a reverse windmill. The craft will probably be very slow but since there is no gravity it doesn't matter as long as the pseudoplanets are not too far apart from one another. The balloon could be folded when traveling between pseudoplanets to reduce air resistance and deployed again when getting close to have a soft landing.
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I'm working on a version of wormhole-based FTL travel, and one of the side effects of passing through the wormhole is going to be instantaneous heating of every molecule of the thing passing through. The heating works by dumping a specific amount of thermal energy into every molecule of the object passing through the wormhole, and the rise in temperature is thus affected by the specific heat capacity of each molecule.
In a [previous question](https://worldbuilding.stackexchange.com/q/159465/34744) I asked about the maximum amount, starting from normal body temperature, that one can suddenly heat a human's entire body by. It turned out to be rather small, not much more than 1°C above normal. We can do a bit better than that by giving people mild hypothermia beforehand, so we're going to say that, as we can safely send humans through it, this wormhole raises the temperature of human flesh by about 4°C. This means that it dumps about [14 kJ/(kg\*°C)](https://chemistry.stackexchange.com/a/97738) of thermal energy into everything that passes through it.
This means that some substances which have much lower specific heat capacities would be heated by a substantial amount. The air in the spacecraft, for example, would be heated by about 14°C. Copper wiring would go up by over 36°C. Any spacecraft parts made of Tungsten would go up by almost 105°C. These temperature increases could cause the spacecraft to begin to leak or cause other dangerous situations. So, **what major issues would there be with suddenly dumping 14kJ of heat into every kilogram of a spacecraft?**
To clarify, the spacecraft in question is specially designed for this type of transition. The question is asking what would have to be designed differently and what could still go wrong.
[Answer]
Almost everything in your spaceship can be specifically designed to handle your temperature increase without any noticeable side effects. It’s just a matter of engineering it properly. Electronics can simply use a different conductor, such as metal impregnated ceramics. It’s a challenge, but doable. The areas you really need to be concerned about are chemical reactions. Since we have no idea what resources your spaceship has, we’re guessing at least you have some form of chemical fuel.
**Fuel:** The chemical reactions needed to propel your craft will be sensitive to changes in temperature. Often modern spacecraft use cryogenic fuel for maximum energy density, this kind of fuel system will obviously fail catastrophically (remember *everything that touches the fuel* is heating up). But even gasoline, kerosene, or diesel reactions will change to some degree if you preheat the fuel. Some reactions improve, others go the other way. It depends on your fuel.
**Rations and provisions**: Any form of food or rations will essentially get “microwaved” so the crew has to come up with a plan to remove energy from those items and plan the meals appropriately.
**Medical implants**: Absolutely anything inside your crew members needs to be considered. This means titanium pins for bone repair, dental fillings, pacemakers or other electronic prosthetics, etc.
**Clothing:** Did your spacesuits have titanium zippers inside? Aluminum? The spacesuits need to be engineered just as carefully as the ship, however people will be inside of them. Make sure you are not building a microwave oven for the crew! And don’t forget the boots!
**Jewelry:** Earrings, necklaces, wedding rings, nose or tongue studs. Think “all metal = bad” if it touches the crew.
**Glass and other ceramics:** Brittle ceramics may crack with heating. Everything made with silicate or hard ceramics needs to be designed not to crack under heating.
**Plastics**: Usually metal parts have plastic handles or coatings, which may melt and emit toxic fumes. This is another design challenge your engineers need to tackle.
[Answer]
The first major issue would be electric and electronic failure.
Since high-loaded processing units (central, graphical, etc) work at temperatures near to maximum (50-60-70C), rising it by 20-30C would stop and even damage them.
Many parts of high-energy electric network also produce heat (transformers, bad contacts) and superheating can damage them or activate fuses or other security measures. Spaceship can loose energy in random subsystems.
Second major issue are liquids and gases.
Here the main point is *how fast this "sudden heat" dumps in*. If it is really instantaneous - it's bad news. This would create a sudden rise in pressure and shockwaves. Many hermeticaly sealed full liquid containers would crack or explode (medicine, water pipes, fuel lines, life-supporting equipment, full fueltanks).
Air pressure would jump by 7%. This would cause a [barotraumas](https://en.wikipedia.org/wiki/Barotrauma) to humans and may damage some non-structural elements of the spaceship (shatter glass, break inner doors, lights, monitors, damage ventilation equipment). This effect would not be that devastating since air is all around these objects, but in some unfortunate cases (when shockwaves from corners meet at or near objects) that may happen.
The third major issue would be fine mechanics.
Solids would also experience these shockwaves, but structural metal elements (like hull or engines) would not be damaged. But say doors (airlocks) and turbines, motors, other complex equipment can get stuck and/or break. Rotating turbines (say in engines or generators) would do it violently.
The main problem with this heating that it is sudden: it would be like a strike, like a small explosion all over the place
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[Question]
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This is a submission for the [Anatomically Correct Series](https://worldbuilding.meta.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798)
This is the latest in a long series of questions I've asked on my fantasy world which contains many mythical and folkloric creatures. I won't link the other questions since at this stage the series has become huge.
The Isitoq is a creature from Inuit mythology. [This book](https://rads.stackoverflow.com/amzn/click/com/B01F2A2HE4) describes it like so:
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> The Isitoq . . . is covered in coarse hair. Its eyes are divided by a large mouth containing one tooth flanked on either side by a short one.
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A Book of Creatures illustrates the Isitoq like this:
[](https://i.stack.imgur.com/ZGknO.jpg)
**What could this creature plausibly be, in terms of ancestry and relation to real animals?** A few criteria;
* Rely on the written account more than the picture, which is vulnerable to extra stuff added on by the artist
* I'd prefer if it didn't have a really early POD (e.g. it's a surviving dinosaur), because that would cause many other changes due to the Butterfly Effect
* It has to be something which could realistically exist in the Arctic, from a biogeographical standpoint. As a random example, penguins live in the Southern Hemisphere and have always lived there, so no penguins please.
If you can find other reliable accounts of the Isitoq's appearance **as told** in traditional folklore, you can use them as well.
[Answer]
**They are hominids, displaced to the far north by Homo neanderthalis and then Homo sapients.**
I am reminded of Clark Ashton Smiths [Gnophkehs](https://monster.fandom.com/wiki/Gnophkeh) - hairy cannibal humanoids occupying the far north. They are part of the Lovecraft mythos now and appear in one or two of his stories also.
The Isitoq have fur, as is helpful for cold climates. These hominids, because of inbreeding / evolutionary bottleneck, have fused incisors. Depicted are the front two fused in a member of our species. The Isitoq have all 4 incisors fused, and these are flanked by the canines. The molars are set farther back and out of sight.
Otherwise these relics have much in common with other hominids, including cooperation, culture and so on. Of course they eat humans if necessity requires it. So do humans when the go wendigo. Starvation is always around the corner in the far north.
[](https://i.stack.imgur.com/M872b.jpg)
<http://forum.dentalxp.com/case/details/treatment-options-fused-anterior-maxillary-teeth-number-8/2873>
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The Isitoq could have evolved from a predatory jawed leech that increased in size to allow it to feed on larger prey. They may become more intelligent to find prey, and so also become endothermic. They would also evolve larger frontal eyes, due to needing to find prey at longer ranges. They may also need larger, more specialised teeth, such as a long tooth for killing prey and 2 shorter canines/molars that can tear up meat. Competition may increase, and so they might move into colder areas. To keep warm, they might start to wear the pelts of their prey, sticking them on with their slime.
[Answer]
You asked for anatomically correctness not how did they evolve or why but still I will try to make them as most earthly possible.
**4 eyes**
The isitoq actually has only 2 **eyeballs** but 4 total eyes, how?
Some people are born with more than one pupil in each eye, it is a dissease but people born with this rare condition are fertile which means that if it was to be to useful then it would eventually be selected over having one pupil per eyeball.
As it happened with the four eyed fish Anableps.
\*\* vertical face splitting mouth\*\*
Thats just orofacial cleft a not so rare mutation that happens in humans with a 0.02% chance and it causes the upper lip to to be split, vertically and sometimes it can go even beyond and split the skull and fusing the nose and mouth into one hole.
The isitoq is just a more extreme variation of that dissease that, this can be obtained by inbreeding.
Inbreeding in humans has happened many times in history and created some strange looking humans... Blue people exist because of Inbreeding so the idea that humans with that particular dissease taken to the extreme could evolve is not too far from reality.
**teeth to the side of the mouth**
This is easy, almost every person on earth ishas some teeth deformities and some the most extreme ones can result in teeth pointing forward and poking the lips or inward. You can either explain it as another teeth deformation that got worse through evolution, and this can actually happen and has happened.
Just look at warthogs, elephants and narvals.... They all started off with normal teeth and became freak animals.
Or you can explain them as being just exposed bones of the nose.
**Living in the artic**
This creature is perfect for that, it's short and fat which means it's really good at maintaining heat
Tall and skinny people lose heat easier, that's why Neanderthals where chonky and short kings. The fact that it they are covered in fur makes it even more realistic.
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I'm running a D&D campaign and am using a modified map of Venus for it that shows what Venus would look like with similar amounts of water to Earth. The problem I'm running into is mapping the ocean currents around the equator at this point of the map where a centrally based gulf has land on either side of the equator. Would it still create an equatorial counter current? The other problem I ran into was how this ring of land would affect ocean currents within it. Would it rotate within itself or would it be more likely to force itself through the small waterways around it? [](https://i.stack.imgur.com/ZeCa1.png) This is the gulf causing me issues.^
[](https://i.stack.imgur.com/lvYld.png) This is the ring.^
[](https://i.stack.imgur.com/pm7Jn.jpg) This is the globe as a map to give better context.^
[Answer]
As Venus rotates in the opposite sense of other Solar System planets, the equatorial current would flow from West to East. As you turned down the map, it would flow from rigth to left as on Earth's maps.
Coriolis force would create on the Gulf, placed at Northern Hemisphere on Venus, a counter-clockwise sense superficial current as on Southern Hemisphere on Earth, so it could create a countercurrent. My guess is it will create it.
[](https://i.stack.imgur.com/jAdPf.png)
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The sea at the left of your map you named ring at the weastern whould be a [Thetys](https://en.wikipedia.org/wiki/Tethys_Ocean) type Ocean, named in Oceanography also Mediterranean Seas.
Superficialy [Coriolis force](https://en.wikipedia.org/wiki/Coriolis_force) would create short basins. At Earth major currents surrounding the landmasses take place in counter-clockwise sense, but this is also related other factors:
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> [](https://i.stack.imgur.com/wzgoW.png)
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> Source: [researchgate.net](https://www.researchgate.net/figure/Map-of-the-Mediterranean-Sea-with-the-name-of-the-sub-basins-main-currents-white-lines_fig1_316850029)
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At your sea I would expect, as it is placed at Northern Hemisphere, to have a main current flowing as at Southern Hemisphere on Earth, counter-clockwise:
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In depth mediterranean currents are dominated by convection from the surface to the seabed:
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> [](https://i.stack.imgur.com/pZKbT.jpg)
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> Source: M1 Oceanography notes. University of Bordeaux.
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At the Strait of Gibraltar that deep water flows over the vast ocean, interacting with its deep water. That's what would happen at your sea as, if I am not wrongly interpreted your map, it is partially open at the West. Here the sense of rotation would not take effect, as your sea should have more salinity than the ocean and deep circulation is thermohaline.
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> [](https://i.stack.imgur.com/CbYJx.jpg)
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> Source: [pinterest.es](https://www.pinterest.es/pin/479633429035718278/)
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The replacement of water would create an input current, resulting for the closed sea:
[](https://i.stack.imgur.com/6VfQ9.png)
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For my world I would need a really large swamp (or similar kind of wetland). It should be about 200km in diameter, which should be quite possible given a large enough flat terrain and enough rain.
The problem is that this environment needs to be completely isolated from the mainland: my small humanoids (around 70cm high), that have a technological level similar to that of natives of the Amazon basin, shouln't be able to reach the mainland or, if possible, shouldn't even know of it's existence.
Unfortunately, putting the swamp in the middle of the ocean like an island isn't an option, as the kind of plants able to grow in such saline environments are not suited to the environment I want to create.
This would lead to the need for a really large lake, which raises two questions:
1. Is it even possible for a swamp to exist in the middle of such a large lake?
2. I know It's possible for large lakes to have currents, winds and tidal movements, and even seasonal currents, like the Great Lakes; but could there be any conditions under which these currents and winds are so strong as to make it impossible for my civilization to cross this barrier? This could also help justify their knowledge of the existence of the mainland without any settlers there, and could lead to quite a bit of mythology I might get interested in.
[Answer]
To have a swamp, you have to have 3 things:
1. A flat area to collect water that slowly drains out (you want a
swamp, not a lake).
2. Somewhere for water to collect that feeds water into the flat area
(mountains) around a large portion of the flat area so you don't have just one source cutting a river channel through it.
3. Rain. Lots and lots of rain.
If you have impassible mountains around a good chunk of the swamp and ocean on the free edge(s), it is unlikely that you will have a lot of traffic to the area.
It seems to me that you are looking for something very like the Amazon Basin you mentioned. You could, essentially, make South America an island but you said that you don't want an island. If you make the mountains taller, you can cut the area off from the rest of the mainland. the trick is to have them tall enough that even the passes are well above the tree line. That way the only way to the swamp is to sail there.
In this scenario, the swamp could well be seen as "past the edge of the world."
[Answer]
**Put it on a mountaintop.**
<https://www.researchgate.net/figure/Maringma-tepui-Authors-tent-on-the-very-top-of-the-mountain-looking-SWW-Mount-Roraima_fig4_259759794>
[](https://i.stack.imgur.com/vAR0q.png)
Depicted: [Maringma-tepui](https://en.wikipedia.org/wiki/Maringma-tepui)
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> Maringma-tepui has a maximum elevation of around 2,147 m (7,044 ft)[1](https://i.stack.imgur.com/vAR0q.png)
> or 2,134 m (7,001 ft).[3] The summit plateau has an area of roughly
> 170 hectares (420 acres) and is highly uneven, allowing water to
> collect in many deep, swamp-like pools.[5] It is predominantly covered
> in low-growing "tepui meadow" vegetation, quaking peat bog, and some
> dwarf forests of Bonnetia roraimae, with few areas of exposed
> rock.[1](https://i.stack.imgur.com/vAR0q.png)[5]
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Here is Maringma-tepui from a distance.
[](https://i.stack.imgur.com/R1XK2.png)
When I was in Kauai, I went up onto a mountaintop and was surprised to find a swamp with boardwalks up there. The coolest thing were all the tiny sundew flower - these mountaintop swamps are nitrogen poor but rich in insects that get blown up there, and so good habitats for carnivorous plants. What you need is a depression up there that can collect water and a substrate that prevents it from draining away.
Tepuis have been used as isolated habitats in lots of fictions - their steep walls limit access and egress and all sorts of weird stuff might be hiding on top. The top of a steep sided tepui would be perfect for your swamp people.
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I was recently redesigning some mostly hominid Aliens I designed a long time back in high school and felt were a little lackluster, and since they were already Tall, Wiry, and vaguely Shambolic-Looking before, I came up with the idea of giving them greater flexibility and strength by giving them a spine similar to that of Ferrets and other long, slinky sorts of mustelids, left over from a time in their evolutionary history when they were predominantly arboreal hunters, scavengers, and occasional carrion feeders.
In addition to increasing their overall length/height compared to most humans, this allows them to bend and contort their bodies naturally in ways humans have to train for years to accomplish, possibly even farther (without significant Injury, of course). Their wiry muscularity also makes them deceptively strong, a bit like a coiled spring; this is enhanced by the fact that they also have two sets of arms, which [this post](https://worldbuilding.stackexchange.com/questions/74254/anatomically-correct-multiarmed-humanoids) suggests that a longer spine and ribcage could help accommodate (one pair is generally longer than the other, and positioned to be better for lifting, grabbing, climbing, and other activities requiring a wide range of motion without getting in the way of the other, while the second pair is used more for jobs requiring fine motor skills closer to the body- both can still be used fairly deftly, however).
When I looked into the skeletal systems of ferrets, minks, and weasels, I also discovered that they have a far more flexible ribcage, which can expand and contract to some degree when compressed or released, and allow the animal to cram into tighter spaces while still protecting their internal organs- this partly appealed to me because I had been playing around with the idea of giving this species the ability to partly unhinge their jaw and swallow larger food items, and some of the other threads I've been reading on here suggest that you'd need a much more flexible ribcage for that to work?
Thing is, however many generations on, they've developed into plantigrade bipeds like us, and I imagine their spines would give them the look of perpetually slouching in a lazy and faintly delinquent-looking fashion, generally only straightening up to their full height to reach tall objects or intimidate potential foes (which actually works really well with the General Personality of most of the characters of this species I've written so far XD); I also imagine that they'd start to get more bent as they aged, and that a lot of them would start using various forms of spine braces and bindings as they got older. These are just all the things I've thought of off the top of my head, I'm not sure what other effects this might have.
However, my main question concerns their legs- Their feet are fairly long, with long toes like those of raccoons, opossums, and some lemurs to help them stabilize when upright, but I'm not sure what kind of leg is better to support their body structure; Long Thighbones with comparatively shorter shins, or Long Shins with comparatively shorter Thighs? Would they have to stay constantly bent-kneed/bowlegged, or could they support themselves with the same stance as our legs usually take? Would their Pelvic situation need to be different? Should I skip plantigrade and look at another leg structure entirely? Should I scrap the whole idea and start over? I don't know nearly enough about legs, can someone just... generally explain how they work to me XD
[Answer]
Considering evolution is a form of adaptation to the environment, I wonder what has lead your ferrets to evolve into plantigrades.
For example, *Eohippus*' [finger-like foot](https://www.britannica.com/media/full/topic/152990/74688) adapted it for living in the bush, whereas horses' hooves are better suited for prairies. Here, I am not talking teleologically: the environment might have *triggered* evolution by favouring certain mutations or, esle, some mutations might have appeared and then be *co-opted* for further use (that is, either "environment meets evolution" or "evolution meets environment").
Drawing on your description, it appears to me your ferret-like people (whether intelligent or not) have matched their evolved bipedal posture with new environmental challenges. I presume their **environment of early adaptation** must have been some kind of grassland, which requires high posture to navigate and ward off predators while, at the same time, it would still contain sufficient hindrances to running to justify the retention of feet whose surface ratio is higher compared to their mass.
The more I think of it, the more your people seem to me to be like **thin kangaroos**. Kangaroos are marsupials, all right, but [they have a bipedality that nicely shows how a species can retain surface ratio](https://kangarooproject.weebly.com/uploads/7/3/3/1/7331585/7263727_orig.jpg) while, at the same time, walk (or leap) on two feet only.
This said, I would conceive the thing as follows:
* Femur becomes shorter over the generations
* Posterior paws become slightly longer
* Higher tibia to femur ratio (so, a longer tibia)
* Jumping gait instead of walking gait (this is a major behavioural change)
* You still retain some sort of shambling look
* If the species is intelligent and has spread to new environments after evolving in a primordial one of sort, you may think of them as able to "walk short distances" while, at the same time, leap and jump whenever its convenient. Their civilisation should reflect this.
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[Question]
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I'm aware that variants of this question have been discussed before (such as "how to build a self-sustaining medieval city?"), but my question comes at the problem from a slightly different angle.
Imagine that you are tasked with taking around 10,000 people, and imprisoning them within an enclosed city-space, from which they cannot get out, and nothing can come in (how that is to be accomplished is not relevant to the question). In other words, the isolation of the city is absolute, and after you've done your job once, even you can't intervene any further.
The only condition is that the people or their descendants should not die out - i.e., the enclosed city must be able to sustain itself at a basic level, and for a couple of thousand years. You belong to a rather high-technology civilisation set in the distant future, and so you have a near-God-like freedom in designing the elements of the city - the location (for weather and climate), the soil, availability of water etc. You cannot build anything specific for these people - all of that they are meant to do for themselves.
The people in question are, at present, at the same technological level as you, but there is an expectation that forced isolation will, over generations, lead to a sharp regression.
I've studied the previous discussions on similar topics, and I have a pretty good idea of the ratio of farmland to population (and other similar considerations) when it comes to the question of food. What I'm specifically concerned about is (a) designing a sewage system, (b) sources of clothing, and (c) the disposal of dead bodies. Any suggestions on those counts - and of course, any element I'm missing out in ensuring that the city survives - would be most welcome.
**Edit**: A few clarifications in response to the questions below. By "enclosed", I am only referring to a physical enclosure - say, by an impenetrable wall, or, as someone suggested below, a force-field. Sunlight etc, in the normal way, is all available.
One exception to the "enclosed" rule is the existence of a river, that runs through the city, and passes underground (and ultimately beyond the barrier between the city and the rest of the world). The source of the river is not known (to the inhabitants), and the dominant explanation for its existence is (obviously) a religious one.
[Answer]
**Recycling is the easy part**, as this is a future society, we can rely on atomic manufacturing techniques which all the full disassembly and reassembly of atoms. This nicely avoids the recycling issue, at the expense of power. Power can be worked out by having some sort of near-infinite crystal-void-energy-make-it-up power supply. Think a [ZPM in Stargate](https://stargate.fandom.com/wiki/Zero_Point_Module).
The length that this power supply operates on, its peak power, and reliability is the determining factor in how long the city could survive for (technologically speaking), as once sealed the city likely does not have the ability to make more.
**Cities do not exist in isolation**. A city develops to supply a point of exchange, usually trade, or labour, to the region it exists in. When either or both of those run dry, the city dies. This scales up and down from village/township right through to mega-city.
To enclose a city so that even information cannot enter/exit essentially stops trade. It also ham-strings labour. So there really needs to be an artificial supplier of labour demand. The most likely such supplier would be a religious organsiation. We have many examples in our history of mostly self-sufficient edifices such as conclaves, monasteries, etc... Each was a product of religion.
The religion would probably operate with a caste system, or pseudo caste system. Free thinkers will be promoted to a prison (or gilded cage) neutralising their threat. All of the required professions will be trained by the religion, and workers will be given few freedoms and encouraged/demanded to participate in numerous brainwashing/community activities. Those who conform will be public praised, and those who don't will be made into public spectacles.
As the religion is primarily focused on maintaining control, and benefits from a relatively naive community, it will naturally dismiss and reduce the technologies in general use. It will maintain many of the technologies for itself and use these to re-enforce their own status. Some of these technologies will stop being understood even by the elite in the religion.
Human Resourcing is the tricky part. The population will naturally have years with more births, more deaths, more disabilities (permanent and temporary), etc... That means some decades there will be less workers than demand, and other decades will have more workers than demand. With ten thousand individuals in your society, that roughly means a work-force of 7000 people (3000 people are babies/children/elderly/sick). Of those 7000 all positions in growing/manufacture/transport/management/etc have to be filled at least twice, in order to have some elasticity built in for years low in available labour.
For years with excess labour, the religion will need to perform some form of public/spiritual works. These would be *golden* years for the religion displaying true faith, etc... The problem is that each spiritual/public work will consume resources (limited in supply) and space (also limited in supply). Destroying, or allowing such works to deteriorate will cause general resentment in the population.
[Answer]
# Not a city. A town with farming villages.
With 10,000 people, you can forget internal combustion engines and most other heavy industry. That means most people will work in agriculture, toiling in the fields from dawn till dusk.
* For sustainable agriculture, you need quite a lot of area. Enough to have not just crop rotation on your fields but also rotating areas between farming, grazing, and forestry on a centuries-long schedule. That handles your burial and sewage problems, too. Human "nightsoil" on fields can cause medical problems, so put it into forest reserves.
* Clothing is wool, cotton, or the other traditional methods. If there are animals there will be leather as well.
* There might be some iron and even steel production and blacksmithing. At that scale, A hill with iron ores would be plenty for a couple of millenia.
# A Long-Term Balance is Difficult.
If you have enough resources for 10,000 people at a sustainable rate, then humans will breed 11,000 people, or 20,000 people. Who needs a forest preserve, cut it down and farm. What do you mean, the water table is dropping? I want my red meat on the table!
[Answer]
Much will depend on your future society's moral & ethical foundations.
Since you are proposing a (reasonably) hermetically sealed city that ought to remain so for the next few millennia, I am going to assume that your society really doesn't give a fiddler's fart what happens to the prison-city or the people within it, so long as the population held in the zoo doesn't die out.
(If you want a truly hermetically sealed prison-city, you need to build in on or in the Moon. And with very robust city service systems.)
Keeping it on Earth, and assuming sufficiently high technology, I'd go for the simple solution. Build a 250 foot tall (and deep) force field all the way around a, say, ten square mile bit of okay land. Not prime real estate, but land that people who want to survive can survive on. Since I can't build anything for them, I'll simply create and stock a reasonable supply dump for them: basic building materials (cement, sand, bricks, stone, lumber, etc.; basic tools for working in these materials; basic reference materials for learning how to "live off the grid"). And then simply turn on the power to the force field and leave them to it! This supply dump should be enough, if they're smart, to build themselves a few great-houses, barns, sheds & workshops. Once they figure out how to make bricks or hew stone, then they can build other needful buildings.
Your specific concerns:
* designing a sewage system: I'm not really sure why we care. Any rate, we can't design or build anything for them -- they have to do this themselves! Basically, they'll just come up with their own version of Shits Creek and eventually cover it over and make a cloaca maxima of their own. Designing a (proper) sewage system for them absent anything else proper doesn't make sense. We will have to build some kind of sewage treatment system *outside* the prison-city's perimeter, however. This in order to take care of any contamination that leaches through the soil or runs down the drainage from their land to ours.
* sources of clothing: Basically the same answer: why do we care? They're on their own. They can figure out how to kill an animal and process the hide from the library we gave them; they can also learn how to husband wool bearing animals and then spin and weave their yarn into cloth. Or they can go entirely or mostly naked. Humans can survive (and can evolve) being naked to downright chilly temperatures (think Tierra del Fuego).
* the disposal of dead bodies: Ashes to ashes, my friend. They have or can make a couple spades. All they need is two strong lads to dig a shallow trench and lay the corpse to rest in the old sod.
At the other end of the experiment I suspect that the descendants will a) be rather hardy but of a now much lower technological level and b) quite possibly still pissed off your "civilisation" imprisoned their ancestors in a big cage without considering the grave miscarriage of justice done to generations of innocent people.
---
Just two follow-up questions, if I may:
1. Won't there be a problem when the initial building dump runs out?
The initial supply dump is not designed to last very long, especially when compared to the overall length of time this "experiment" is designed to run. Since one of the experimental conditions is that we can not build anything for them and the other is that their progeny ought to survive, the least we can do is get the initial inhabitants "over the hump".
The area selected for their city ought to contain sufficient resources (stone at the very least; sand, clay, woodlands, water as well) that they should be able to manage their own store house of supplies going forward. If some people of intelligence and foresight come into leadership roles, I don't believe the initial supply dump will be problematic.
Any problematicity of initial supply dump size is, once the prison-city's barrier is energised, no long of our external concern. Any problems with amount or selection of supplies falls to the inhabitants to sort out on their own. They will have to make do or do without.
2. The presence of wool-bearing animals would, I imagine, require a further extension of the city limits, in order to provide pastures for the sustenance of these animals?
This is a good point. While I think 100 sq.mi. is a pretty good size (that's the size of Washington DC) a larger size would be possible in theory. The largest ranch in the US is something like 3000 sq.mi. Increasing the size of prison-city's perimeter that much will simply become a function of land available for the project vs private ownership of said land (if that concept exists in your culture) vs existing land occupation, use & presence of structures.
This situation could work to advantage, however: since we are obliged to **not build anything specific for these people**, the previous existence of dwellings, storage facilities, barns, shops, some kind of sewage & potable water infrastructure solves some of the issues at hand.
It will simply fall to the new inhabitants to manage the extended range of resources they've been blessed with. Armed with basic common sense and some basic resource materials (text books & technical manuals), they should do just fine.
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[Question]
[
In this setting, the family unit is based around a clan system. An individual's wealth and status is related to the clan they are born in, and its ancestry is based on matrilineal lines. Marriage does not exist in the form we would recognize. Instead, this culture practices a form of exogamy, in which the male leaves his own family to join the household of another while the female stays in the clan she was born into.
A man doesn't marry an individual, but marries into an entire clan. Sometimes, groups of men marry into a clan at once. This leads to many offspring coming from the same father. A cultural belief system has developed in which boys are considered "sons of society" and raised in bulk while girls are "daughters of their mothers" and raised specifically by their mother.
Polyandry has largely been viewed as unstable in our world. This system of having multiple males married to a household can be problematic. How can this society avoid that and maintain its stability?
[Answer]
What you are describing in your question is actually a form of group marriage rather than actual polyandry. The problems that you will encounter in such a group marriage will come primarily from the attitudes in the culture regarding the ownership of sex. In a group marriage situation, all members of the group need to feel like they have equal or fair ownership of the sexual collateral shared by the group, otherwise there will be conflict regarding how sex is shared.
The obvious solution to this problem is the imposition of a cultural norm where resources (including sex) are all communal property of the clan. This would result in a very strong expectation that everyone should always do "Whatever is best for the Clan" in all situations. Members of the clan who's actions are not in line with this will be objects of ridicule and scorn, perhaps even including expulsion from the clan.
[Answer]
>
> This system would leave large numbers of men unmarried, which has historically led to an increase in violence.
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Why would unmarried men become violent?
In most societies in our world men are supposed to only have sexual interactions with their married wife (or wives). "Cleaning the pipes" on their own is still seen as inferior solution and was portrayed as a health risk in the past to enforce sexual abstinence outside of marriage. There's an obvious statistical correlation: Men without any sexual outlet tend to become more violent. In countries with prostitution illegal and a societal stigma (or even laws) against premarital sex the rape rates are significantly higher than in countries without this. (Thanks to ArtificialSoul)
If you remove this barrier to sexual satisfaction for unmarried men you could remove a lot of frustration and potential for agression. Being invited into the bed of a noblewoman is a high privilege, but even the lowest ranking man should have a place he can go to satisfy himself.
Depending on how you want to portray your society, you could have the typical female sex worker, but it seems that male sex workers would be more realistic in your setting.
Female workers:
* Could be regarded with the highest respect due to the stabilizing services they provide for their society
* Could be the second born, third born... who are selected to perform services (like third born sons where sent to monestaries in the past)
* Or they could be expelled and outcast daughters
Male workers:
* Could be forced to work until they're married
* Could enjoy higher previleges and more rights for their services
* Could use the service as a means to promote themselves as satisfying husbands
If you find the idea of sex work repelling, you could install a culture of free dating in your society. Have dedicated places (like gardens) on each clans property where everyone willing to share a bed comes to at night. Women have free choice, of course, and those men who were not selected for the night find a male partner. These places should also exist in public areas to give unmarried men the same opportunity.
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[Question]
[
**Premise**
In this world, there is a global government that is all-powerful. However, what makes this world interesting is the type of government structure of the global government. It is not a junta, democracy, or a theocracy. One could argue this world government is a scientocracy, but it's a very specific field of science that they base their decisions around -- Philology. I had to double check the meaning, and I will include it here for reference:
>
> **Philology:** the branch of knowledge that deals with the structure, historical development, and relationships of a language or languages.
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Now, I will coin a word to explain the central government of this world:
>
> **Philologocracy:** A form of governance whereby all decisions revolve around preserving the existing linguistic heritage of the world.
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For example, this Philologocracy would deeply frown upon a language group with less than 1,000 native speakers. It would promptly issue policies to increase the adoption and revival of the language. That's the basic idea, but of course the devil might be in the details. The other part of the Philologocracy definition I want to explain is the emphasis on *existing* linguistic heritage. This means the central government is off the hook for languages that are already dead, but they could of course be studied as a hobby. So in short, the Philologocracy's mission is to not let any existing language die out.
This world has a specific type of Philologocracy, an egalitarian Philologocracy. In this form of government all languages must have EQUAL populations of native speakers. This spells doom for our big languages like: English, Chinese, Spanish and so forth. At the same time, this is an unexpected miracle for anyone with a soft spot for tiny language groups. For instance, Chinese speakers shouldn't outnumber an African tribe language like [Maasai](https://en.wikipedia.org/wiki/Maasai_language). Approximately all 6,700+ languages must have equally sized populations of native speakers.
**Question:** How can the Philologocracy take our world, which seems to have formed from a mix of political, military and economic influences to a world that has a balanced population size for each existing language in the world? I'm just looking for a general overall strategy. To keep the scope within reason, consider these objectives:
**Objectives:**
* Increase birth rate of endangered language populations
* Ensure adoption of endangered language, that it may be "revived"
* Impose a form of punishment for not speaking the endangered language (note: the death penalty might not work here since the Philologocracy may not have the guts to follow through executing the precious remaining native speakers)
* Reduce birth rate of large language groups
**Success Metric:**
All existing languages have equally sized populations of native speakers
**Further Clarifications:**
* Assume total passivity of the citizens of this world (whatever the
central government says goes)
* Assume the world the Philologocracy inherits is the real world of
today
* Ethnic heritage is preferred, but external groups may be added as
needed for the case of a *truly* tiny language where undue inbreeding
is a risk.
* Territory can be re-allocated as necessary to support the new
landscape of the world. Each language group should have enough land
to have reasonable autonomy.
* Radical redrawing of boundaries is allowed.
* Dialects can count as a language if they are different enough. To make it simple consider the line in the sand to be mutually intelligibility. For instance, Cantonese and Mandarin would make the cut, but Farsi and Dari would not. When choosing which to keep, choose the older one. If it is uncertain which is older, think of a clever political maneuver to justify one over the other.
* Language must have existed in the past. The Philologocracy will not accept a language that was made up yesterday.
* Fictional languages are not in consideration either. They can continue to exist in the movies, but there won't be any real life Kling'On states.
* A group of people can only speak one native language, and are limited to being able to speak 2 other languages, but only at proficient level.
[Answer]
As a start, your phylologists could mimic the various strategies pursued by ecologists (in order to get a political influence and preserve biodiversity).
Their points of view are very similar : they see diversity as a treasure and uniformization as a threat. They want to protect endangered species, or endangered languages.
So, the first part of the strategy is to convince people that their fight is meaningful. Why uniformization would be an issue for the world ?
You must spot the danger, and name the ennemy.
Let's imagine that they see global standardisation as a dangerous process, and they think that actual leaders of the world want to make everybody similar, to make them easier to control.
People with different languages see the world differently, have their own concepts and culture. They have their specific identity ans tastes. But many world leaders want everybody to follow the same track, buy the same things, vote the same way. Some of them want to destroy local languages, to weaken minorities and strenghten their own power.
The phylologists may want to overthrow those leaders, and promote diversity. They should convince people that they face a risk, and that uniformization will have a negative impact on their life. They need to educate them about cultural differences, and the richness of languages. Because those who don't know much about others, don't care.
With ecology, you must think local AND global. If you take only the local aspect or only the global aspect, it won't work. I think that the language issue is similar. They must fight at a local level and global level.
So they should find a way to unite the various minorities that are fighting for their identity (and trying to preserve their language) to become a political force, and count on the international scene.
Once they are strong enough, then can act as a lobby and promote their program to protect language diversity. But they will face strong opponants, so it's not going to be an easy fight, and will take decades.
They will have to be patient. A more brutal strategy, like using the force to reach their goal, might not lead anywhere.
Their only chance is to think on the long term, and bet on the next generations, to create a new world order.
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[Question]
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A volcanic eruption is measured in two constants--gas and viscosity. For clearance, low viscosity is like squirting water off a nozzle, whereas high viscosity is like squirting caramel off a nozzle, which takes more effort to do, which makes it more dangerous.
In geology, there are four different kinds of volcanic eruptions:
1. Low Gas + Low Viscosity = A quiet lava flow.
[](https://i.stack.imgur.com/MmAYj.jpg)
2. High Gas + Low Viscosity = A fire fountain eruption.
[](https://i.stack.imgur.com/mzwri.jpg)
3. Low Gas + High Viscosity = A dome-building eruption. (This sort of eruption doesn't reach critical right away.)
[](https://i.stack.imgur.com/yGIYr.jpg)
4. High Gas + High Viscosity = A Ring of Fire explosion.
[](https://i.stack.imgur.com/U24DY.jpg)
These sorts of eruption are impressive enough on land, but in the event of someone doing some serious worldbuilding, this question puts three of the four types underwater. Type #1 has long been confirmed to happen underwater, but the oceanic differences in temperature and pressure have produced a different result called "pillow lava".
[](https://i.stack.imgur.com/P2mo8.jpg)
Is it possible for eruption types numbers 2, 3 and 4 to occur underwater? If yes, then would the oceanic differences in temperature and pressure make them look and act differently from how they have acted above sea level?
[Answer]
Underwater volcanoes have basaltic lava, which is poor in silicates. This means their lava is low viscosity, so you are pretty much limited to type #2.
However, since a low viscosity magma is also less capable of capturing gases on the long term, the only way to have low viscosity and high gas is a late mixing of water and magma with the resulting formation of high pressure steam.
Being underwater strongly reduce the bursting of steam, as water pressure can increasingly counter the steam pressure with increasing the depth.
That's why most of the observed type #2 eruptions happen closer to the surface, like in the [Isola Ferdinandea or Graham Island](https://en.wikipedia.org/wiki/Graham_Island_(Mediterranean_Sea)).
[Answer]
First, for (2) and (4), the key element is decompression - volatiles (Mostly CO2 and H2O) coming out of solution as the pressure decreases. However, the solubility increases exponentially with depth (unfortunately all the good links for this are pay-walled). So in any significant depth of water (more than a few hundred meters), these eruptions can't really happen because the magma can't decompress sufficiently.
For (4) as well, many of the effects of the eruption come from a column of superheated gas and ash that rises into the air in an [Pelean Eruption](https://www.britannica.com/science/Pelean-eruption). This then collapses to give pyroclastic flows. Obviously this won't happen underwater. In shallower water, you'd get a hot mix of water and ash, and some [submarine pyroclastic flows](http://www.d.umn.edu/~rmorton/ronshome/Volcanology/Subaqueous%20Pyroclastic%20Flows%202010%20Hudak.pdf).
(3) is interesting; but the presence of water would lead to explosive fracturing, and I suspect a block and ash flow as described above.
Overall you will see fewer if any actual explosions, but a lot of ash/block density-driven flows.
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[Question]
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I am creating a board game that requires an underground cavern world, with huge pipes that pump air for the civilization living there. The underground region is at about 35-40 degrees north latitude. I am wondering what sort of climate such a region would have. Is it really just no weather?
I am thinking that there will be convection from the air pumps, and if the ceiling is high enough, clouds of mist might form if it is humid enough. There will probably be bio-luminescent organisms, or rat-like creatures. The climate will be relatively cold for its latitude; because there is no sunlight, the only sources of heat will be the giant air pumps.
Does anyone have a similar logic for the climate, or is it different from what I thought?
[Answer]
# Underground temps vary little
The average annual temperature in [Chicago](https://en.wikipedia.org/wiki/Chicago#Climate) is 51 F (11 C). If you are in a cave a mile below Chicago, it will be 51. It will be 51 in the day, and at night; in summer and winter. The average annual temperature on the surface will be roughly the temperature of your cave. If your cave is below [Delhi](https://en.wikipedia.org/wiki/Delhi#Climate), it will always be 25 C; if it is below Moscow it will [always be](https://en.wikipedia.org/wiki/Moscow#Climate) 6 C. Pick surface climate and that will determine your cave temps.
# Humidity depends on how much water is in your cave
The partial pressure of water in the air for a closed system will be dependent on the surface area of exposed water. If there are lots of underground lakes and rivers, humidity will be high; little of these and it will be low. [Transpiration](https://en.wikipedia.org/wiki/Transpiration) by plants would increase humidity, but without a sun, I don't know what kind of plants you might be thinking of.
# You will never get mist
The chances of getting mist are pretty low in anywhere with a roof. When air cools, its ability to retain water drops. On the surface, air can move upwards and cool as pressure decreases; in a cave, air will cool by coming in contact with the walls. Once there, any moisture it loses will end up on the walls. You will get condensation, and possibly 'rain' as condensed water drips off of the ceiling, but not clouds of any sort. Since temperatures are steady, any area with rain will almost always be raining. Any area that isn't raining will almost never be raining.
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[Question]
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The world is mostly safe now, but everything has been scavenged from the old world. I live where winter always reached [-20F or lower outside](https://www.gardenia.net/plants/hardiness-zones/4). Our colony has a hundred people and a few working electronic devices, no one else is better off.
The last of my scavenged coffee is running out. I am open to anything but caffeine is needed in my morning ritual.
How can I get enough caffeine to replace my 16oz of coffee a day without being able to purchase/scavange it?
[Answer]
You can build a greenhouse or a growing room and grow the following:
* Plants: Guaraná, Yerba Maté, Cola nut (Kola nut), Cacao, and all the coffee/tea plants.
It's your only option.
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[Question]
[
**Outline**
A planet which is heated tidally by its Brown Dwarf parent and permanently dark needs to have native alien life which has **[somewhat similar biochemistry to Earth]** and also be **[permanently habitable]** by Humans without **[extensive life support]** and/or **[extensively genetically engineered]** bodies.
This planet has very active tectonics and volcanism, a result of this tidal heating, a combination of this volcanism and the biochemical nature of this planet's ecosystem should be be capable of producing an atmosphere composed of 22% oxygen, 50-70% nitrogen, 0.02-5% CO2, ~7% water vapor, + **[leftover]** + trace.
If this atmosphere is not achievable, the atmosphere needs to be otherwise **[permanently habitable]** to humans, these humans could have physiological adaptations to adapt to this atmosphere through non-**[extensive genetic engineering]**.
Volcanism on this planet produces similar gases and particulates in similar concentrations to those on Earth (just use Earth numbers);
*The principal components of volcanic gases are water vapor (H2O), carbon dioxide (CO2), sulfur either as sulfur dioxide (SO2) (high-temperature volcanic gases) or hydrogen sulfide (H2S) (low-temperature volcanic gases), nitrogen, argon, helium, neon, methane, carbon monoxide and hydrogen. Other compounds detected in volcanic gases are oxygen (meteoric), hydrogen chloride, hydrogen fluoride, hydrogen bromide, nitrogen oxide (NOx), sulfur hexafluoride, carbonyl sulfide, and organic compounds. Exotic trace compounds include mercury, halocarbons (including CFCs), and halogen oxide radicals.*
(From wikipedia: [volcanic gas](https://en.wikipedia.org/wiki/Volcanic_gas))
Most members of Trophic level 0 (producers) on this planet produce energy through the chemical equation:
12H$\_2$S + 6CO$\_2$ → C$\_6$H$\_{12}$O$\_6$ + 6H$\_2$O + 12S
However other methods do exist; such as those relating to elemental Sulfur, ferrous Iron, etc. (see [Chemotroph](https://en.wikipedia.org/wiki/Chemotroph)) Photosynthesis is not a viable way to produce energy on this planet.
Through some **[reasonable]** system, (either other processes which these trophic level 0 lifeforms engage in or through related related lifeforms, etc.) this combination of geology and ecosystem needs to produce the atmosphere outlined above, or at least an atmosphere habitable by Humans.
**Note that really, the main goal of this is to create an ecosystem which can produce oxygen through some chemical process involving life, so that this planet can have Earth-like quantities of oxygen in its atmosphere**
**Note that CO2 can have a lot of variance in its percentage of the atmosphere, greenhouse heating can be countered simply by moving the planet farther away from the brown dwarf, though this only works while the planet is still being heated tidally (CO2 likely wouldn't be produced as much from volcanic gases because less tidal heating means less active volcanoes); this is why I've let the range of allowed CO2 concentrations be between 0.02% and 5%)**
**Definitions**
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> somewhat similar biochemistry to Earth:
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Humans can gain energy through carbohydrates from alien flora and fauna, and alien life lacks substances which are particularly dangerous to Humans. Note that this does not necessitate things like having nutrients, proteins, and lipids which are necessary for Human life.
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> permanently habitable:
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Humans can live on this world for an excess of 15 thousand years
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> extensive life support:
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Life support apparatuses which either contain
*entirely different atmospheres inside the apparatus than outside*, or
*are built to keep hazardous gases and particulates from contacting all parts of the Human body*
(Eg. this does not include things like gas-masks)
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> extensively genetically engineered:
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Different from Earth-humans to an extent that
*radically changes the human appearance to an extent where we would not recognise them as human*,
*extensively changes the physiology of humans (adding organs or systems, changing the basic function of organs or systems, significantly changing the human skeletal structure)*
Note that this does not include things like adding some kind of filter to the Human respiratory system which gets rid of dangerous gases or particulates, adapting human skin to be resistant to corrosive atmospheric gases or particulates, etc.
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> Reasonable
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The system needs to have some reason to exist; for example, water electrolysis is an obvious way to produce oxygen from the products of H$\_2$S chemosynthesis, however the lifeforms on this planet need to have a *reason* (and way) to engage in water electrolysis.
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> Humans
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Whenever I mention the word Human, it doesn't mean Earth-human, I mean whatever kind of genetically engineered adaptations are necessary to adapt to this environment
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> Leftover
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This just means any other necessary byproducts
[Answer]
**Stratospheric electrodissociation of water.**
Water can be split to hydrogen and oxygen by non-biological methods. On earth this is mostly [photodissociation](https://en.wikipedia.org/wiki/Photodissociation) because we have a star which is gushing radiant energy.
If I recall correctly, this is the rogue planet you asked about here as regards a light source.
[Life on a rogue planet](https://worldbuilding.stackexchange.com/questions/99726/life-on-a-rogue-planet/99729#99729)
This planet is analogous to Jupityer's moon Io. Interactions between the moon and its planet could create energetic auroras.
<https://en.wikipedia.org/wiki/Aurora>
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> Auroras are produced when the magnetosphere is sufficiently disturbed
> by the solar wind that the trajectories of charged particles in both
> solar wind and magnetospheric plasma, mainly in the form of electrons
> and protons, precipitate them into the upper atmosphere
> (thermosphere/exosphere) due to Earth's magnetic field, where their
> energy is lost.
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>
If there is energy enough to produce light there is enough energy to do abiotic water hydrolysis. Electrochemistry happens in our upper atmosphere too but discussion of this is dominated by oxygen and ozone chemistry. I imagine it must be difficult to distinguish oxygen caused by electrodissociaton of stratospheric water versus oxygen that came up from the surface.
In any case: a plausible method for oxygen on your planet is that the energetic auroras serve double duty. Water coming up from the warm ocean surface (and water volcanoes! don't forget them!) would put water up into the stratosphere where there are enormous electrical charges. Oxygen and ozone rain down from the surface.
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I saw [this video](https://m.youtube.com/watch?t=657s&v=Evq7n2cCTlg) a while ago, and recently it's gotten me thinking. Towards the end of Artifexian's video on gas giants and habitable moons, he mentions the idea of having 2 habitable moons in a horseshoe orbit. An example of a horseshoe orbit would be Saturn's moons [Janus and Epimetheus](http://www.planetary.org/blogs/emily-lakdawalla/2006/janus-epimetheus-swap.html). Once every 4 years, they swap orbital altitudes.
There's already been [a question](https://worldbuilding.stackexchange.com/questions/42673/seasons-and-day-night-cycles-on-horseshoe-habitable-worlds) about seasons would work in this setup, so I'm going a different route.
What kind of tidal forces would 2 habitable moons in a horseshoe orbit exert on each other? Could it hinder the habitability of either moon?
When I say habitable, I just mean the usual stuff. Water, Breathable air, and somewhat Earth-like gravity. If it helps in forming answers, these parameters can be pushed. Never said humans had to live here.
I was imaging one moon as a mostly Earth-like planet, and the other as a mostly water world if that helps with answering this question.
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Earth experiences pretty significant tidal forces, and it doesn't seem to affect habitability too much. The crust flexes, the oceans rush in and out, and we're fine. Some life actually relies on it.
Io, a moon of Jupiter, experiences significant tidal flexing, enough to generate serious heat and geological activity. So, it seems entirely possible for tidal forces to be strong enough to effect habitability. Constant volcanoes filling the air with ash and toxic chemicals, serious earthquakes moving dirt around and preventing plants from taking hold.
So, you're question really boils down to "How strong are the tidal forces experienced by horseshoe moons?" Which is a very difficult question. The strength of tidal force is mostly based on distance, and it can be very difficult to predict how close these moons get to each-other.
To get extremely close together, they would have a large difference between the innermost and outermost radius of their orbits. They would approach each other at a higher velocity. They would swap quickly. They would repeat their swaps more often. (relatively, we're still looking at several orbits to complete the swap and several hundred orbits between swaps)
A horseshoe orbit that never gets very close is pretty much the same thing, but slower. The two moons are always close to the same distance from the planet. The swap places at a greater distance from each other. Since they interact with each other more weakly, the swap takes longer. It might be tens of thousands of orbits between swaps.
tldr; It can probably be whatever you want, but the details are hard.
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So I've got a werewolf species inspired by [this Tumblr post](https://drferox.tumblr.com/post/159026911411/fantasy-biology-the-werewolf). Basically, the default form is somewhere between human and wolf, but gets hairier and more muscular over the course of a month as the full moon approaches.
I really like that the post uses a modified Fossa as a wolfish/humanish base, so my werewolves will likely have a shortish snout. They'd also have thin human lips that get fuller with the moon as well.
Here's my question: would a werewolf made with thin lips, a short snout, and long canines be able to talk? Would it be hard to understand them?
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Assuming the rest of the vocal apparatus is human-shaped and has comparable features, yes, they would be able to talk. Vocal resonation would be quite off, and the pitch would likely be higher - rather than growl, your average werewolf would tend to yip (but that may vary as it depends on several other factors).
The lip thickness matters little; much more important is their flexibility. Harder lips would make it difficult to articulate labial consonants. Same difficulty for canines, which might impair labiodental phonation unless lips were *more* flexible than a human's.
How much difficult would it be to understand such a being depends on the language it spoke. [Some languages](https://en.wikipedia.org/wiki/Iroquoian_languages) might be easier than others. It could speak English in Morse code - slow, awkward, but possible.
The key thing is, neither snout nor teeth are necessarily showstoppers. A much more modern-human lookalike, the [Neandertal man](https://thehumanevolutionblog.com/2015/02/09/did-neanderthals-speak/), might have, or have not, spoken intelligibly depending on the exact shape and location of a throat bone.
Conversely, if the internal vocal apparatus remains modern human, chances are that your werewolf will be able to speak and be understood. Problem might arise from other sources such as respiratory frequency and control; say that the werewolf needs a faster respiration to help fuel its metabolism and get rid of waste heat (maybe with the help of the tongue), this will greatly reduce its freedom of speech and/or degree of comfort in speaking, like a human with shortness of breath.
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It depends on how the werewolf in question works. If it's some sort of physical shapeshifting of a human body, then it depends on the form the body shapeshifts into, and the degree of changes that occur. If they go full wolf, probably not; if they turn into something anthropomorphic wolves akin to those commonly seen in the furry fandom (though most such werewolves possess less neotenous/cartoonish features than furries), with a wolflike head and a humanoid body, then maybe, depending on the configuration of the throat. If they're something like the Wolfman, where it's mostly just the superficial features of the face being altered, then almost certainly.
If it's some sort of spiritual possession, where the human body remains unchanged, or where the entire werewolf is spiritual in nature, then it probably varies depending on the magic involved with that setting's magic functions, and it may involve conceptual features like "animals cannot speak", so a creature that becomes animalistic cannot speak, or "spirits speak the spirit tongue", so werewolves speak the spirit tongue when in their wolf form.
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I would think that anything with a snout of any length would have a very strong accent in any human language so they could speak but would have difficulty being understood by those who were not fluent in their dialect. It would be similar to dealing with someone with a severe speak impediment. The exact impediment would depend on a number of factors, chiefly:
* vocal cord length
* tongue length and dexterity
* bite pressure (because it affects jaw flexibility)
* the position and length of the animals' teeth, not only the canines although they're likely to be the most important
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This is a bit hard for me to put into to words, but it is an idea I have been working on for a few days, with input from a few other people. I have actually brought up part of this in a previous question that I asked.
The scenario is a large space station with rings that are not connected to the station by spokes, but by a magnetic rails similar to a maglev train. The goal of the scenario is to sabotage the station in a way that is both a complete catastrophe, but does not destroy the station entirely (some destruction is acceptable).
Excerpt from novel: "*The station was essentially a stationary drum encased by four, counter-rotating rings. What could be considered the base of the drum faced away from the planet and acted much like a massive satellite dish. The other end of the station directly transmitted information to and from the surface. Rotating at just over 280 kilometers per hour, the rings were suspended and propelled around the station by magnetic rails.*"
**If the saboteur were to cause the magnetic rails to lock up in a sort of emergency braking system, what sort of forces would be excerted on the station? How would I calculate them? What sort of effects might I see?**
Further station details:
* Inner ring radius: 620m
* Outer ring radius: 650m
* Inner rotation speed: 280 km/h
* Rotations per minute: Approx. 1.2
Assuming a magnetic braking system similar to Linear Eddy-current Brakes found on high speed trains, I'm unsure of how to calculate what sort of deceleration I would see. On the other hand, if the momentum throwing all of the ring's occupants to the wall produces too much force for survival, I would need to know the maximum (reasonable) impact force survivable. I would then need to work backwards from that value for an appropriate breaking speed.
On top of all of that, I am aware that Eddy-current Brakes produce quite a bit of heat to conserve the loss of kinetic energy. I need to know how to calculate that heat, but can't seem to find any equations relating to it directly. This could be another major factor because I don't want to cook everyone inside, but I wouldn't mind melting or warping the magnetic rails.
Another factor to consider is that the sudden slowing of one ring will throw off the equilibrium of the station since the counter rotating rings are now at a 2:1 ratio instead of 2:2. I suspect this would force the entire station into an incalculable spin, simply because I don't have any really masses or measurements for torque. That said, if someone disagrees on that I would love to know how badly these people are screwed.
---
Addition:
For anyone interested, [here](https://titaniumturt1e.deviantart.com/art/Coeus-709494436) is a link to an early version of the chapter. It has been edited a few times and some parts have been changed to improve the flow of the story, but it's roughly the same for the most part. The part where this event takes place is at the end of the chapter, but please read the whole thing and let me know what you think.
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There is some missing data to fully answer your question, but some things can be said:
* There are four counter-rotating rings, so I assume two are turning clockwise while the other two will be rotating at the same speed counter-clockwise.
* If above holds true then stopping all of them (presumably at the same time) will not make the hub start rotating (i.e.: the total momentum o Space Station is null throughout the event).
* Total energy to be dissipated is (as correctly says @pojo-guy) $ E = 1/2 m v^2$; we cannot calculate it because we miss $m$, which is the total mass of the four rings.
* Deceleration strongly depends on the magnetic field applied to generate the eddy-currents, among other things.
* Deceleration depends on relative speed.
* Complete formula appears to be: $F = \nu v B^2 \sigma$ where:
+ $F$: braking force.
+ $\nu$: Volume of the conductor.
+ $v$: Linear velocity.
+ $B$: Magnetic field.
+ $\sigma$: Conductor's conductivity.
+ Reference <https://www.physicsforums.com/threads/calculating-the-magnitude-of-eddy-currents-retarding-force.822714/>
* Without these data we cannot compute deceleration, time needed to stop rings and thus the expected smashing force (as said force is proportional to speed, so it will be maximal at start and then diminish; this is the worst possible because it means a sudden high deceleration with almost no warning).
* There won't be any rotational effect on hub, but it will be subject to a severe torque whose size will depend on the above applied force.
* The whole energy (see above) will have to be dissipated as the magnetic rail gets hot; that is quite difficult to do in space and you seriously risk it melting down, unless braking is very gentle.
* A magnetic rail doesn't mean you won't have "spokes" connecting the (stationary) rail to hub; this system will be severely stressed while braking.
* In general I expect all these variables to be computed by whoever designed the thing in the first place, so that any brake you may have would be compatible with structural strength. If you want something catastrophic you should think about some means to have the braking system work outside its specifications (e.g.: "enhance" magnetic field).
**EDIT: to follow OP comment**
If just *one* of the rings brakes then resulting disaster is much *less* severe because:
* just one ring and the hub will be affected.
* all other rings, assuming a frictionless rotation on magnetic rail, will not experience *any* disturbance.
* Ring has a much higher moment of inertia than hub (exact data needs mass and dimensions of the various components).
* braking effect would be to equalize rotation speed of hub and braking ring.
* angular momentum is preserved, so a part of ring momentum is transferred to hub, in proportion with their moments of inertia.
* rule of thumb would say they will both rotate ~1rpm after braking, so neither will have very high impact:
+ ring change in speed is small because angular speed does not change much.
+ hub change in speed is also small because it does not have a large arm to multiply angular speed.
* energy is not conserved, but the excess kinetic energy lost by ring and not transferred to hub will be turned into heat at brake; but it will be *much* less than in the first scenario (all rings brake).
* also stress on magnetic rail spokes is much reduced.
* the *only* scenario in which this would result in wild rotation is if main axis of moment of inertia of hub is *not* near the main axis of rotation.
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A 50g impact/deceleration is going to cause injuries, possibly some fatal, but won't directly kill most people, 100g is usually fatal, thank you Mythbusters. I think you will see some rotation and some [precession](https://en.wikipedia.org/wiki/Precession) due to a partial shutdown. Other than that there's not enough data, mainly we need the Mass of the ring before we can start doing the math on the rotational mechanics side of things, [this page](https://physics.info/rotational-kinematics/) has most of the equations you'd need to work things out. The other principle effect I'd watch out for is "pile up" the movement of unsecured mass, not least liquid fuels and water reserves, towards the direction of the rotation, depending on the structure and strength of the ring this could buckle the structure.
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*I posted this comment:*
*I just can't see a massive space station suddenly stopping. Even with brakes. Just too much momentum. If it comes with brakes to slow it to a stop then surely the engineers have already accounted for what would happen so that there's minimal if any damage. As for ship or asteroid impact: shoot it down before the impact. Its messed up in the case of the ship, but the needs of the many...*
*Which prompted the OP to object with:*
*@Len I don't see where there wouldn't be any reason not to have some sort of breaking system. It would make complete sense to bring the ring to a stop for repairs or the works would be flung away from the station, and it would need to stop quickly if there was sudden damage that might be more dangerous to continue spinning. The idea is that the saboteur would trigger the sudden braking and disable the safety measures meant to protect the people inside.*
**I get what you're saying. I just think there are better ways to do the same thing.**
Briefly... The ring wouldn't need to stop for repairs because any works on it would be going at the same speed as it is. If an astronaut goes to work on the outside of the station he wouldn't fly away once he stepped outside. He would go along with the station.
Aside from say, a massive comet crashing into the space station, there could be no more dangerous thing to happen to it than stopping suddenly! Everything inside would get flattened against walls from the sheer momentum! Anything not secured would go flying and become a deadly projectile. A pen would become a bullet. Any liquid inside would get thrown around. Say you wanted to have a pretty lake in the middle of the space station, if the station suddenly stopped that lake would become a rushing mountain of water smacking you like an avalanche.
Also the energy required to suddenly a stop something as large as a space station (you did say it was a large one) would be astronomical. The engines that put the space station into its spin in the first place built that energy up over a long time. its not something that happens as easily as flipping a switch and voila now we have spin. And, just before it reached its desired speed it would already start a the slow down process so it would remain at the desired speed, instead of overshoot, making it too fast.
Its a very finely tuned balance with mathematical equations I wouldn't even begin to understand (I'm sure some genius here will chime in on that [and it might be good for both of us]). in other words the engines the put that station into its spin would have to go in reverse for just as long as it took for it to go forward, expending a ridiculous amount of energy for no benefit.
Imagine a set of beer cans back to back suddenly crushing into one another. That would happen to the body of the station ring. The stresses would be overwhelming. And contrary to popular belief space stations will most likely be built from quite the flimsy materials. Walls of aluminum are not out of the question (with some kind've radiation shielding inside, but that would be fairly minimal too) since all it has to do is keep air inside. A balloon could do that.
A braking system that stops a space station *suddenly* is not the good idea you think it is.
**Here's my suggestions for how you can achieve a sudden stop:**
Catastrophic damage. A huge explosion or collision. A saboteur could crash a ship into it, or smuggle an explosive aboard, or destroy a nuclear power plant that was already on board.
Space is filled with lots of objects that could crash into it. A swarm of particles would do lots of damage. A rock the size of a golf ball could puncture just the right thing that does lots of damage.
And even then the wreckage would still keep spinning for some time creating all sort of interesting and dangerous problems for your characters.
Good luck with your story. Sounds fun.
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In my setting I want to destroy the world in a way where people have:
1. Plenty of notice of the impending demise
2. No chance of stopping it
3. They can't engineer a way to survive on earth
4. The rest of the inner solar system is also rendered uninhabitable
I plan to do this by having a large extra solar object, that was previously undetected, on an intercept course with our solar system and will likely be captured into an eccentric orbit of the sun in the inner solar system. This would hopefully cause all the inner planets from mercury to mars to either be thrown out of their orbits or eaten by the new arrival. I was planning on having this object be a brown dwarf or a super Jupiter.
The problem I'm not sure about is: if an object that big was under a century away I think we could have seen and discovered it already.
So my question is: **What is the largest astronomical object that could be overlooked, assuming modern or near future technology, until it was only a few decades away from intercepting our solar system?**
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**Black Hole**
A black hole passing by and attracted by the gravity of our sun would be insanely devastating and probably undetectable until is really close to see their effects in the outer rim of our solar system.
<https://en.wikipedia.org/wiki/File:A_star_is_consumed_by_a_black_hole.ogv>
**Supernova**
Not exactly an object getting inside our system but there is already a theory that a "relativy closer" supernova caused a mass extintion on our planet.
<https://en.wikipedia.org/wiki/Ordovician%E2%80%93Silurian_extinction_events>
The gamma ray burst could strip the planet from his ozone layer in an instant allowing that the sun radiation reach the earth killing almost all live.
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1. Plenty of notice of the impending demise
2. No chance of stopping it
3. They can't engineer a way to survive on earth
4. The rest of the inner solar system is also rendered uninhabitable
Numbers 1 and 4 are easily possible and conceivable with earth's current knowledge etc.
Number 2 and 3 are interesting. You can write it such that they can't stop it, regardless of their technology level, by introducing another element, something like an independent pandemic scenario or other global catastrophe - Rise of our robot overlords or something.
In practice, we humans don't seem to worry about doom scenarios until it is close enough to really matter. then, we freak out. This happened with Y2K and is happening more obviously now with global climate change, and nuclear proliferation in some parts of the world. I think the number of years till collision is immaterial. Plenty of people won't worry about events that are far out there - They think there is no reason to, for something far in the future.
So, through a combination of normal human social behavior and/or independent world events, you could make it so that by the time we took it seriously we would be out of time.
As for #3, a collision or other huge event will disrupt plant's severely(decreased sunlight.) if it [did in the dinosaurs](https://knowridge.com/2017/08/dinosaur-killing-asteroid-could-have-thrust-earth-into-2-years-of-darkness/), it could do the same to us. We starve - And getting to that point is ugly (I bet some people start cannibalizing.) I suppose we could make biodomes, but there are definitely ways to make your planet inhospitable. Maybe some folks make it, but there would be a pretty big collapse.
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Transit of a Pulsar through the inner solar system;
1. Just like a comet or asteroid you'd have to be looking right at it to spot it, but it's an emitter not a reflector so we could spot it much farther away we'd know about it from 10s or even 100s of light-years away.
2. Unless you can make a significant change to the velocity of either the solar system or an object that weighs 2-3 times what the Sun does it's going to happen.
3. & 4. The radiation output would be enough to sterilise a huge swath of the solar system, not just Earth, tidal forces would create massive Roche Tides on Earth and the other rocky worlds, think force a 10 earthquake everywhere on the planet for days or weeks during the transit. Long term the gravitational perturbations would also turn the whole solar system into a shooting gallery for millennia to come with Main Belt, Kuiper and Oort objects thrown in every direction.
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Okay, so imagine a situation where most of earth's atmosphere is lost, the pressure at sea level is somewhere around 0.3 atm. If it matters, let's say that this is the result of the gradual escape of air during a period of a few years. Disregarding the prospect of life under such conditions, I'm more interested in what would happen to the climate in such a situation.
So in this scenario, the total amount of water vapor in the atmosphere would be expected to rise a bit due to the decreased vapor pressure (at least that's what I think would happen, though this could probably be negated by things such as temperature changes).
What I'm looking for is mostly an idea of the most general effects on Earth's climate. How would such a change affect the average temperature, day/night temperature cycle, winds, rainfall, and anything else you might eventually think of?
Oh, and hi.
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I would start by considering how the atmosphere on Earth behaves at the altitude where there is 0.3 atm of pressure, and then adding in surface effects with the oceans (mainly) and the ground (secondarily). According to this calculator (<https://www.mide.com/pages/air-pressure-at-altitude-calculator>), the earth has an atmospheric pressure of 0.3 atm at about 9076m, so roughly at the top of the highest mountains. At that altitude, several types of clouds exist (<https://scied.ucar.edu/webweather/clouds/cloud-types>), and the interesting ionospheric effects are still above you.
For the same energy input from the sun, the atmosphere will be colder because less infra-red will be blocked. The surface water would likely freeze, so there would be less surface wave effects. Water would enter the atmosphere more by sublimation that evaporation, and the air at sea level would be much drier.
With dryer air, there would be simpler atmospheric phase-change dynamics. Cyclonic storms may be less frequent and severe because there would be less of the cycle where condensing rain heats the atmosphere, which becomes warmer and less dense, supporting the inrush of surrounding moist air. This last statement is a guess. It may be that snowing would, in a less dense atmosphere, cause the same cyclonic storms as we have now.
There would still be an equator-to-pole-to-equator cycle, as the poles would still be colder from the less energy input per square meter. Movement of air away from the equator would still cause Coriolis forces to induce latitudinal movement.
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Your pressure is lower, so you rightly infere that there will be more evaporation. The problems start now...
Having a thinner atmosphere also means you have less shielding of UV radiation, which has the ability of cracking molecules. So your water vapor is going to be split into O2 and H2.
Well, H2 is not going to last in the earth atmosphere: it will escape to space soon. Once all the hydrogen is gone, you end up with more Oxygen or oxydes, but no water clouds. Just winds...
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My current story is set inside a hollowed out dwarf planet (i.e. Ceres) with an artificial gravity generating "mesh" within the shell. This *Gravity Mesh* can generate a gravitational field that can be modified, anywhere between 0.01g and 10g in strength.
On Earth, sea level air pressure is 101.33 Kpa, and the Armstrong limit (the pressure at which water boils at human body temperature [37 degrees celsius]) is 6.26 kPa, which usually occurs at around 19,000 meters. The elevation at which humans usually need supplemental oxygen is 4,500 meters, which has an air pressure of 57.73 kPa.
What I would like to know is, how would changing the strength of the gravitational field affect the air pressure.
* What would the air pressure be at "sea level" at 2g? 5g? 10g? 0.01g?
* Would the different gravities alter the elevation at which humans would need supplemental oxygen? If so, how?
* At what elevation would the Armstrong limit occur at these different gravities?
* What is the highest gravity before humans breathing the air would go into a state of hyperoxia (too much oxygen)?
Assume the atmosphere consists of a standard nitrogen/oxygen mix with Earth-like stats at 1g.
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# The Physics
Since we're assuming an Earth-like system (1 atm at sea level with Earth's *g*), there's a convenient formula we can use for this:
>
> [](https://i.stack.imgur.com/yLRtC.png)
>
>
>
As you can see, pressure is a function of:
1. **Height**, *h*. You have asked for a profile of pressures as *h* varies.
2. The **gravitational acceleration**, *g*. This is your free parameter.
3. The **temperature**, *T*. For simplicity, I assume a constant ambient *T* of 25 Celsius.
**The other terms**: *k* is the Boltzmann constant, and *m* is the mass of the air molecules. This is taken as the mean for gas mixtures. These are fixed parameters.
So now we can plot a few curves and take a look:
[](https://i.stack.imgur.com/RJEIA.png)
We can can calculate the heights at which the Armstrong Limit occurs for each value of *g*. They are:
* 1997.8km at 0.01x *g*
* 19.978km at 1.0x *g*
* 9.9889km at 2.0x *g*
* 3.9956km at 5.0x *g*
* 1.9978km at 10.0x *g*
As you can see, the Armstrong Limit happens rather quickly at 10x *g*, just above 1200 miles high.
## Some Remarks
* The Armstrong limit is well-defined and occurs at P = 0.0618 atm, but [*hyperoxia has a much less defined threshhold*](https://en.wikipedia.org/wiki/Hyperoxia).
* Likewise, the range of altitudes at which humans require supplemental oxygen varies widely due to variations in physiology. However, the altitudes will follow a similar trend as the Armstrong Limit.
* For similar reasons, it is very difficult to treat your final question, as the hyperoxia threshold for [even a single person](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2053251/pdf/brmedj03781-0003.pdf) varies widely over many days.
# An Improved Plot
Thanks to SteveES for pointing this out. My original plot had each *P(0)* occurring at the same value; this is inaccurate for the label I used on the vertical axis, which *should* have been *P(h)/P(0)*, not just *P(h)*. Here's an updated plot with the true values. I had to cut off the upper part of the curves for higher *g*. Here is the updated plot:
[](https://i.stack.imgur.com/HFxRk.png)
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Air pressure (atmospheric pressure) multiplies with gravity, so that is easy. Assuming a thorough mix of gas components in the atmosphere, at 0.5 g the Armstrong limit would be 1/2 as high and at 2g twice as high.
Now that is done, the excellent part of this is that by cyclically adjusting gravity and thereby air pressure, air could be made to flow in and out of any cavities in continuity with the atmosphere. Done correctly, humans and all other animals could breathe automatically and without any effort. It would be a **worldwide iron lung**. This would be useful for the very sick, the very tired and the very lazy all of whom would thrive in your subterranean paradise.
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While asking [another question about Jormungandr, the Snakebot of Doom](https://worldbuilding.stackexchange.com/q/76425/75), a point was made that it is so big and hot that it might produce its own weather effects. To that end:
Jormungandr is 446 metres in diameter, weighs 1.486 billion metric tons, has a body that is cylindrical for 7480m, and then tapers down to a point over a further 669m, the tail matching with a similarly shaped mouth. Its armour is made from Tungsten-depleted Uranium alloy plates with a smooth surface coating of Boron Carbide, at the surface appearing to be overlapping scales around five metres long and half a metre thick, much like the scales of a snake. Most importantly to this question, it is driven by shape-memory-alloy 'muscles' that have an operational temperature of around 97°C/207°F, and it has a similar surface temperature in air due to its cooling requirements, but the skin temperature would be much lower in water.
In order to power its huge demand for energy, it is equipped with six hot-fusion reactors, each of which is capable of producing enough energy to power its shape-memory-alloy muscles or its entire complement of rail guns.
While it is rolling sideways, when steamrolling a city, it moves at around 5kph / 3mph. However, it is capable of slithering in a serpentine manner at up to 20kph, and can roll into a hoop and travel at around 100kph on a level surface. It is also capable of travelling underwater, at up to 30kph rolling or 15kph slithering.
In its travels from its construction site beneath the highest point of the Antarctic ice cap to the sea, it rolled at high speed, then travelled along the mid-Atlantic ridge (an area with high levels of geologic and thermal activity), and then surfaced off New York City, which it is presently flattening.
**The question:**
In each of its movement regimes, both above and below water, what effect might Jormungandr have on local and global weather patterns?
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A Snakebot that is perfectly cylindrical would have a surface area of about 28 million square meters. Let's round down to 20 because cones.
Metals have a heat flux coefficient of maybe 5-8 watts per m^2 K. It's about 70 K above background, or about 10 GW dumped to atmosphere all the time.
Thunderstorm scientists measure air energy in CAPE, which is complex to calculate but is about 5000 J/m^3 at worst. Over my head today it's about 300 J/kg. A microcell thunderstorm is about ten kilometers on every side, and heating that much air would take ~days.
In sum: It could trigger rain if rain was in the forecast, but it can't cause rain on its own.
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What would be the geographical and ecological implications for an Earth-like planet that experienced intense volcanic and supervolcanic activity on a scale that, while decreasing over time, was far greater during its prehistoric past than anything ever seen on Earth? Eruptions would have had ejecta mass exceeding 1015 kg and VEIs of 8 or higher. ([VEI](https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index) stands for Volcanic Explosivity Index; 8 is the highest number on this scale that has occurred in recorded history.)
I'm specifically curious about the effect such volcanic activity would have on continents, the fertility of the soil and presence of other natural resources, and, of course, any life that might evolve on the planet in question. Could humanoid life develop on such a planet, or would life be fundamentally different than that of Earth?
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Super Volcanism that extreme means that every other magnitude of eruption will be occurring on an enormous scale. [Super volcanos](https://en.wikipedia.org/wiki/Supervolcano) are driven by an overabundance of internal heat on enormous plumes of magma emerging from the core-mantle boundary. This also means that [plate tectonics](https://en.wikipedia.org/wiki/Plate_tectonics), which is driven by convection in the mantle, will be occurring at an accelerated rate. If this world had plenty of water to form continental crust it would be racing (geologically speaking) around building mountains and creating rift valleys.
This magnitude of volcanism would probably create a toxic atmosphere similar to that during the [Hadean Eon](https://en.wikipedia.org/wiki/Hadean) of Earth which ended ~4000 Mya, but with more sulfur compounds. Any rain would likely be very acidic and the oceans would be acidic too. For the global temperature, I'm not sure because volcanic eruptions release CO₂ and which traps the sun's heat but also ash and sulfur dioxide which has a cooling effect. I will lead towards this world being overall cooler.
Life would likely be some form of [extremophile](https://en.wikipedia.org/wiki/Chemotroph) not unlike what you would find near a [deep ocean vent](https://en.wikipedia.org/wiki/Hydrothermal_vent). I doubt it would get more complex than some form of algae that can metabolize the toxic atmosphere.
Natural resources would be abundant, every bit of the elemental makeup of the world would make an appearance on the surface and the extreme tectonic activity would expose rich seams of minerals. There would also probably be diamonds everywhere due to the abundance of [diatreme](https://en.wikipedia.org/wiki/Diatreme) eruptions and of course ash everywhere.
**Summary:** A hellish world with little to no complex life, but abundant natural resources everywhere.
**Edit:**
After clarification from the OP on his question.
After the Earth accreted and recovered from the moon-forming impact some ~4600 Mya life arose very quickly at about ~4300 Mya but it was not until about ~2300 Mya that oxygen even became present in the atmosphere. There was no real abundant (complex) life on earth until the [Cambrian Explosion](https://en.wikipedia.org/wiki/Cambrian_explosion) about ~550 Mya.
So if your planet suffered extreme volcanism, like the Haden Eon, don't expect complex life to arise for about 3500 Million years after the conclusion of the volcanism. That also is about the time it would take for the atmosphere to even support humanoid life.
You could readily end up with a planet very much like Earth 3.5 Billion years after the volcanism.
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I read somewhere that the size of a planet can influence the number of pressure belts (the areas of high and low pressure that cycle wind, heat and moisture about the globe)[](https://i.stack.imgur.com/QRamn.jpg)
How would you go about constructing these belts when worldbuilding and how are they affected by the planet's size?
Are they also affected by the planetary tilt? (as Artifexian's Video notes how the lines of latitude are influenced by the degree of planetary tilt)
I would like to know this before deciding the size of my fictional planet.
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I don't think there is any reliable study on that.
The only planet for which we have a reasonable of data is Earth.
We have sent probes into the atmosphere of the following worlds:
* Venus: check the Venera missions. The environment in that planet is so hazardous that its atmosphere can be divided in three layers, from top to bottom: **you're safe here in the near vacuum but for how long**, **clouds of sulphur acid and no this is not a joke** and **welcome to hell**. Really. No probe that went in there could ever reach three hours of operation, and they carried very few instruments. We know the pressure is 92 times that of sea level here and there is lightning, but that's that.
* Mars: we have sent plenty of probes there. The air is so thin that it's almost as if there was no atmosphere at all. The pressure is around 1 and 2 % of sea level here. It does have interesting weather patterns (and storms stronger than those of Earth), but research has always mostly focused on the ground, not on the atmosphere.
* Jupiter: this guy has huge pressure belts. They are kinda pretty visible too, in visible light even, thanks to the atmosphere's composition. Problem is, no probe would last more than a couple hours in its atmosphere. It's not as hot or acid as Venus's, but it's too deep and the pressures are enormours. We have sent one probe into it, and there's another one in its way. We are going to learn a lot more about Jupiter's atmosphere but I don't think we would know enough to have a model upon which to answer the question.
* Titan: we have sent exactly one probe in there. It did collect some atmospheric data but we don't have data on its pressure belts as far as I know.
What these four planets have in common is that they are too different from Earth for us to compare. Only Venus has about the same size and gravity, but the sheer heat and pressure, and a day that lasts six months, make it too different from us to serve as a model. Mars has about the same rotation period and the closest temperatures to ours, but the very low pressure makes it a poor choice for a comparison model. Titan's air is too cold and viscous. And don't get me started on Jupiter.
We should probably have a model for comparison when we reach some of the Earth-like planets that we keep finding around other stars, but that should take centuries.
At the end of the day, if you are building a fictional world, you make the rules. Just design your worlds's atmospheres to suit your taste.
I used to play a videogame where the protagonist lived in a gas giant. It had layers, pressure zones and convection. Part of me once said to myself "dude this is so off, there is no way a flying whale could be buoyant enough to float in this kind of atmosphere even if you stuffed its guts with hydrogen, and the wind speeds are unrealistic...". Most other parts of me said "man just chill and enjoy the game, you never complained when it was italian plumbers spanking turtles or bread loaves crawling through walls and stuff". Guess which parts won the argument?
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So I hope my question doesn't cost me too much!
I'm making a game with a lot of lore associated with it. The thing to know is this:
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> in a world were humans are captive from a higher power, two sciences were developed: science as we know it today and soul science: a science where a soul is assumed and build on that very fact.
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Soul and regular science do translate from one to another, in this fictional science the brain is controlled by messages transmitted by the soul, except for one concept:
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> when an individual loses his soul, he gets transported to limbo, leaving his body behind
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In other words, his body simply stops functioning: brain activity ceases, cells don't duplicate, the heart stops beating. All of this is done in a way that regular people wouldn't notice (so no internal/external damage, heart attack, stroke, etc...). As far as we know it he lost consciousness and stopped functioning.
If there is a medically explained way to describe this what would it be? A death that seems invisible to most people?
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Most "invisible" causes of death will stem from the nervous system - it's hard to observe externally.
From an evolutionary standpoint, humans may (?) be more likely to survive to reproduce if they stop spending energy on the brain once the soul has left. This will only happen in rare cases (soul isn't all the way gone, or the body keeps itself alive, etc), but it provides a reason for the soul to be necessary for consciousness - as opposed to that being an autonomous function.
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* **Kill all brain cells.** This is similar to @Tell's idea of removing myelin, which will stop brain cells from communicating. However, there may not be a specific command you can give cells that tells them to strip off that material. Suicide, however, is a command cells are [programmed to receive](https://en.wikipedia.org/wiki/Apoptosis) - and often do receive - so it may be more feasible to kill all brain cells instead of stripping them.
* **Cease signal transmission.** You may get away with avoiding physical changes altogether. If you tell cells to absorb all signals received, [brain death](https://en.wikipedia.org/wiki/Brain_death) will occur. Everything will be perfectly intact before decay sets in, but the "spark" that travels the circuits will be missing, like a turned-off machine. This can happen physically if the brain is able to [produce certain molecules](http://www.oertner.com/PDF/EvankoHighlight.pdf) - no promises there - or if cells are programmed to receive a "lie dormant" signal.
* **Do nothing.** If the soul is needed to tell the brain what to do, there is no reason for it to say "shut down" on the way out. The brain will likely die. Alternatively, if that is painful, the soul can say "go to sleep".
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What about [myelin](https://en.wikipedia.org/wiki/Myelin) ceasing to function?
It is after all the substance that dictates our habits, and thus our choices, as well as the functionality of our organs.
Normally, this will present as degrading ability to navigate space, and a decrease in general health. If all myelin stopped function, it would probably cause a breakdown of the body, as internal communication would cease.
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I think the first question you have to ask yourself is this: How are these brains different from real world brains? Given that our brains function just fine only using biochemistry, you'd have to take away some functionality and replace it with the operations of the soul, if you want to avoid the soul being simply redundant.
The most drastic way of doing this would be by not having a real brain at all, just a type of **"receiver lump"**; an organ with the sole function of connecting to the soul. As far as I understand, Descartes thought that the pineal gland was pretty much this. But if you want to follow Descartes and say that the pineal gland is the seat of the soul, you'd have to ask yourself, "what does the rest of the brain do?"
The Stanford Encyclopedia of Philosophy has a really good article on this: <https://plato.stanford.edu/entries/pineal-gland/>
Mind you, the article also points out a lot of flaws with this idea.
There is also another side to this: Presumably you want to do something in your world with the souls in limbo, so the function of the soul must be comprehensive enough for us to recognize whatever gets transported into limbo as a person. For example, in the article linked above, Descartes ascribes sensory perceptions, the forming of memories and "appetites and passions" *to the body*. As "pure actions of the soul" the article mentions "doubting, understanding, affirming, denying and willing" - without memory or emotional reaction, these don't make up something we would recognize as a person. So if you make the physical brain do too much, you end up with either redundancy or a mutilated soul.
In short, I don't see a way for the brain to be anything but a receiver in your scenario.
Maybe a more elegant way to go about this would be to miniaturize and spread out the function of the "receiver lump": In this version individual neurons are unable to process information. When the neurotransmitters trigger their receptors, nothing much happens in the physical neuron; but the neuron has a soul-neuron corresponding to it, and the electrical energy just vanishes into the soul-neuron, where the different inputs come together and the output is determined. The soul-neuron then triggers (or does not trigger) an impulse, by sending energy out into the physical world again (or not). In this version of the brain, neurons in the brain simply aren't built to deal with the impulses they get – without the soul the impulses dissipate without being able to trigger anything. Once the soul is gone, the brain doesn't do squat.
Conversely, once the body is gone, the soul-neurons lose the connections between them – but you could have them simply regrow these connections on their own, or postulate that one attribute of limbo is reestablishing these connections. It's your concept of the soul after all, you can assume whatever you want.
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In my upcoming book, nuclear war broke out and the survivors were forced to live underground indefinitely.
How would a subterranean city operate, especially in regards to accommodation, movement and architecture?
Will the ceiling be high enough for planes to fly? Will satellites work? Will automobiles work? I'm concerned about how the layout/map of the city will be like without giving its inhabitant the sense of claustrophobia. Cheers!
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To state the obvious, your underground city will be a (natural or artificial) cave, or perhaps a complex of connected caves. It is improbable that the cave would be large enough for a plane. It may be large enough to require cars.
* It appears unlikely that cars with combustion engines would be allowed in. They use irreplaceable fuel and produce noxious exhausts. But some bunkers are [big enough for real cars](https://commons.wikimedia.org/wiki/File:Cheyenne_Mountain_Complex_entrance.jpg).
* You may have electric cars, either powered by batteries or with contact power. The cars could run on rails, like subway cars, or they could be something like a golf caddy. Here is a picture of an [electric train](https://commons.wikimedia.org/wiki/File:15-26-56-ouv-schoenenbourg.jpg) in the [Maginot Line](https://en.wikipedia.org/wiki/Maginot_Line) forts, here [rails](https://commons.wikimedia.org/wiki/File:Balaklava_Naval_Museum_-_arsenal.jpg) in a former Soviet bunker.
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It would most likely be a series of rooms connected by tunnels. More a REALLY big bunker then a city with buildings.
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I'm writing a sci fi thriller and I'm including an inter-species romance scene which involves a pair of star crossed lover, a middle aged man and a mutated botfly no larger than a penny both drifting at a non-lethal distance away from the surface of Pistol Star, a blue hypergiant or V4647 Sgr after their interstellar spaceship got stranded in space during a daring exploration to the center of Milky Way galaxies.
Long story short, the mission ended in disaster and most of the crews as well as their pet companions were killed but that's not the main issue right now, I thought that the survivor and his fetish could somehow get into an outdated astronaut suit made from the 21st century A.D. due to an unforeseen circumstances before making their escape as the ship is about to explode, I just want to know how close can our main protagonist and his fiancee stay in orbit at a safe distance from the surface of the hypergiant apart from the lethal stellar wind before becoming crispy.
Let's assume that the Pistol Star is at least 100 solar mass, the human and the insect are sharing 1 spacesuit together and last but not least please provide your working to support your answer. Remember they should survive long enough to exchange their vows say between 10 to 30 minutes.
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I am not a specialist but I can try :
# Circumstellar Habitable Zone Based Answer
This answer is based on the [circumstellar habitable zone](https://simple.wikipedia.org/wiki/Habitable_zone). Because the Earth is in the Sun's one, and our spacesuits are efficient in this zone. So my guess is if they are in the HZ of the Pistol Star, the spacesuit should be enough to endure the heat.
To calculate the center radius of the HZ, you just have to do `sqrt(Star Luminosity/Sun Luinosity)`, this relies on the fact that the Earth is pretty much at the center of the Sun's HZ, that the Sun-Earth distance is 1 A.U. and that the energy received from a star is inversely proportional to the squared distance from this one.
Furthermore, the [Pistol Star luminosity](https://en.wikipedia.org/wiki/Pistol_Star) is estimated around 1,600,000 L☉, so 1,600,000 times higher than the Sun.
So by making `sqrt(1600000) ~= 1265 A.U`. So the center of Pistol Star HZ is around **1.8924e+11 km**. I think that a good start, you can get them a bit closer of course, because spacesuits could endure the heat a little closer than just above the Earth.
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# Star Luminosity and Spacesuit Capabilities Based Answer
I was wondering if there is a more physics-based answer and I think I found another way to calculate this orbit distance, but I am really unsure about this reasoning.
Firstly, a classic current space suit can hold from [−156 °C (−249 °F) to 121 °C (250 °F)](https://en.wikipedia.org/wiki/Space_suit). Let's say that we want our spacesuit to be exposed at 100°C. We just have to calculate how far from the star the temperature is 100°C.
(This is the unsure part) Then, there is a formula giving luminosity of a black body (a star can be approximated to a black body) depending on its temperature and the distance from it, it is called [The Stefan–Boltzmann equation](https://en.wikipedia.org/wiki/Luminosity#Luminosity_formula) [](https://i.stack.imgur.com/YmyMU.gif), `L in Watt, R in meters, T in Kelvin and σ = 5.67×10−8 W·m−2·K−4`. We just reverse the equation to get the radius : [](https://i.stack.imgur.com/YTEUZ.gif).
Finally, with the data of [Pistol Star](https://en.wikipedia.org/wiki/Pistol_Star), we just have to calculate. `L = 1,600,000`[L☉](https://en.wikipedia.org/wiki/Solar_luminosity)`= 1600000 * 3.827e+26 W = 6.1232e+32 W`.
[](https://i.stack.imgur.com/tLk6m.gif) = 2.105e+14 m = **2.105e+11 km** = 1337 A.U.
Less than 100 A.U. different ! (Yep 80 light-minutes is not that far :P)
But once again I really don't know if my second reasoning is well done.
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250 years in the future, humanity has colonized Mars and the Moon, and built thousands of orbiting outposts and hundreds of O'Neill cylinders in the zone between Venus and Jupiter. The key enabler of this development along with the associated population boom that comes with all this free space is the lucrative asteroid mining business, which saw a massive increase in profit in the 22nd century when antimatter production became efficient enough to support quick and easy travel throughout the solar system.
However humanity's providence has, as it usually does, created a problem. Civilization has overextended, and now requires more resources in the form of metals and liquid water to support all of its off-world colonies than it is capable of providing. Mars refuses to share its abundance of freshwater, preferring to look after its own people first, and Earth's water has become so contaminated with chemical runoff and antibiotic-resistant super-diseases caused by corporate negligence that its vast oceans and lakes are all but useless without expensive methods of filtering.
Without a steady drip of water and metal mined from the asteroid belt, humanity's offworld colonies will slowly waste away and die. The vast megacorporations that rule this future, ever eager to turn a profit, spin this resource crisis into a means with which to grab humanity by its collective balls and squeeze, effectively cornering the market on asteroid mining and its resources by virtue of being the only economic entities with enough resources to devote to the prospect. Decades later, they are the one thing keeping humanity afloat and more or less run society from the shadows by holding the billions of people who rely on their asteroid-mined water and metals to stay alive in the cold, vast expanse of space hostage.
To keep their business profitable, they've begun to bleed resources not just from the asteroid belt but the moons of Jupiter, mining additional ice from Europa to be shipped back to Earth and its off-world colonies. This water must first be desalinated, but compared to filtering the contaminated water on Earth, it still turns a profit, especially with the bulk it can be found in on Europa. As such, a large mining colony has been built inside the ice layer, extending down into the ocean below where in addition to ice mining the native wildlife can be studied for potential use in pharmaceuticals and the biotech industry. This colony is largely populated by scientists and a large number of noncons (non-consensual labor or "non-convicts"; essentially literal wage slaves who serve out their prison sentences doing unpaid manual labor for the company), as well as a small security force.
Is this kind of scenario (i.e. interplanetary water crisis) plausible? Would a mining/penal colony on Europa make sense as an investment in this environment?
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This can only work so long as the corporations have complete control of all means of transportation, because the basic premise (i.e. running out of water and minerals) is simply not plausible.
Any wildcatter or rival corporation setting up shop on Europa will have access to 3X the water that is contained in all the Earth's oceans. Just staying in the orbit of Jupiter provides access to 67 known satellites, and a flux tube which can provide trillions of watts of electrical energy. Moving to the Jovian Trojan points provides access to millions of new asteroids in the Jovian L4 and L5 points.
If a rival corporation has claimed Jupiter, then Saturn provides a similar cornucopia of moons, plus the atmosphere of Titan contains megatonnes of Nitrogen and the composition of the moon seems to be largely hydrocarbons, It *rains natural gas* on Titan.
If you are still stuck, Uranus has so much 3He in the atmosphere you could power fusion reactors to build and drive millions of mile long starships every year. Then you can access Neptune, Pluto, the Oort cloud....
The point is that resource wise, there is so much matter and energy available that any civilization with cheap antimatter can quickly and easily access it. Even using less powerful drives or even solar sails still provides economical access, just on a different timeline (much like sail powered commerce often involved year long voyages).
Since you stipulate a corporate environment, any quasi monopoly on resources is liable to be broken the moment one of the players decides that the profits available from breaking the monopoly are greater than the profits from staying inside the cartel. This problem has plagued cartels like DeBeers diamonds and OPEC for the entire period of their existence, and there is no reason to suspect that corporate players in space will behave any differently. So the period you are describing is quasi stable, the corporations are trying to milk the market for what they can get, but in the background, various corporations and even individuals (depending on how the society is structured) are laying plans to burst out into the deeper solar system and claim the immense wealth available.
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The problem with this scenario is that space statioms tend to be rather self-contained. In an enviornment with high technology and water prices, there would be even less water use, as everything would be recycled. The stations would quickly become closed systems and wouldn't require water.Water is heavy, and sending it across the solar system is much, much more energy-intensive than just filtering the station's waste water and recycling it.
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Yes but only in the short term because ice mining on Europa and other moons would quickly create over supply in place of under supply. Europa probably has more water than our entire planet by a factor of three. The Asteroid Belt also has a lot of H2O, Ceres is estimated to have more water than our planetary Fresh Water reserves and it's a lot closer to LEO most of the time so it's also a good investment.
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I have a world in mind that is essentially a planet-wide underground ocean. The planet doesn't have a strong magnetic field, so radiation on the surface is too high to allow life, but what I'm thinking is that through conduction, the sun can heat the underground ocean through the ground and allow life to begin to form.
The question I have is if this is a plausible scenario. The only forms of life I know of get their energy from radiation (plants), convection (deep-sea vent extremophiles), or by eating other life forms (us). What I'm wondering if conduction is a viable energy tranference mechanism to power life.
Is there anything that makes conduction particularly difficult for life to form around? Are there any examples of life on Earth that gets its main source of energy this way?
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## Thermal conduction will provide a good environment
...but it doesn't directly provide an energy source for organisms to power themselves with. From your description, there's a large underground water reservoir capped with stone to prevent solar radiation from cooking everything.
The question doesn't make any statements about orbital mechanics or distance from the local star, so we will just have to assume that the star provides enough heat near the equator to keep water moving through this underground ocean. There needs to be a thermal gradient or there won't be any circulation. If the poles are cold on this planet, like they are on Earth, then warm pole-bound currents will flow atop cooler equator-bound currents.
**The stone cap isn't necessary for radiation protection** since water does a really good job of absorbing the nasty wavelengths. As this below image shows, water is very good at absorbing the really dangerous wavelengths of UV, IR and other nasties.
[](https://i.stack.imgur.com/XLoO7.gif)
([Source](http://www1.lsbu.ac.uk/water/water_vibrational_spectrum.html))
However, without an atmosphere, something will need to keep the ocean from boiling away and the stone cap does that.
**Stone Cap Complications**
* What happens when sufficient pressure builds up to blow off some of the cap? If there are undersea vents, some kind of gas is going to come out and that won't always stay in suspension.
* Does the cap reseal itself after a volcanic eruption? If so, how?
* If this environment is intended to create a space faring species, how do they make the transition from purely aquatic to living in an atmosphere?
* Are there sufficiently large & stable gas pockets that an ecosystem can evolve in them?
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Awesome question. To test the feasibility of your idea, we start with the [heat equation](https://en.wikipedia.org/wiki/Heat_equation), which in our case is (from [these notes](http://www.pci.tu-bs.de/agbauerecker/VorlesungSolarthermieUndWaermepumpen2014/WaermeeintragErdeLecture17_Spring2004.pdf))
$$\frac{\partial T}{\partial t}=D\_H\frac{\partial^2T}{\partial z^2}\tag{1}$$
where $T$ is temperature, $t$ is time, $D\_H$ is the thermal diffusivity, and $z$ is elevation. $D\_H$ can be calculated simply as
$$D\_H=\frac{\lambda}{c\_v}$$
where $\lambda$ is the thermal conductivity and $c\_v$ is the volumetric heat capacity of the soil. Exact values for $c\_v$ can be calculated if the soil’s porosity, volume fraction of organic matter, and volume fraction of water are known; soils that are not homogeneous (i.e. that contain a mix of things, as is the case with most real soils) involve slightly more complicated calculations for $c\_v$. Slide 10 of the notes gives values of $c\_v$ for the four individual components of soil: minerals, organic matter, water, and air. $\lambda$ must also be calculated from the various values of $\lambda$ of each of its constituents.
Solving this gives us
$$T(z,t)=T\_0+(T\_s-T\_0)\text{ erfc}\left[\frac{z}{\sqrt{4D\_Ht}}\right]\tag{2}$$
where
$$T\_0=T(z,0)=T(\infty,t),\quad T\_s=T(0,t)$$
and $\text{erfc}(x)$ is the [complementary error function](https://en.wikipedia.org/wiki/Error_function).
The example given in the notes finds a $D\_H\approx8.907\times10^{-7}$ m2s-1; if we take the initial temperature at the top of the underground ocean to be that of [deep-ocean water](https://en.wikipedia.org/wiki/Deep_ocean_water) (around 32-38 °F, or 0-3 °C, or 273-276 K), and assume that the crust is around 100 meters thick (I’m just taking a random value of this), with the planet having an [effective temperature](https://en.wikipedia.org/wiki/Effective_temperature) $T\_s$ of about that of Earth, at 252 K as per the equation), then we get
$$T(\text{top of ocean},t)=252\text{ erfc}\left[\frac{100}{\sqrt{4\times8.907\times10^{-7}\cdot t}}\right]=252\text{ erfc}\left[52979t^{-1/2}\right]$$
Notice that as $t\to\infty$, $T(\text{top of ocean},t)=T\_0$, so the heat will eventually reach the water. The big problem, though, is that it’s going to take a long time for changes in temperature to propagate, because of the large depth of the crust. As we can see by taking the derivative of $T(x,t)$ with respect to $t$, heat will move relatively slowly.
This is made worse because the surface of the ocean will cool. I assumed this value of $T\_0$ to be true at the start of the heat conduction (i.e. at the very beginning of the planet), so the ocean will slowly start to heat up. It might have been better to study the *change* in temperature $\Delta T$, $T-T\_0$. Other things I’ve ignored include the actual effective temperature of the planet, which may be nothing like that of Earth, and circulation of water from the depths of the ocean, however thick it is.
Here’s the big problem when you’re trying to help life survive: The energy source isn’t too good. You’ll of course have the equivalent of a [geothermal gradient](https://en.wikipedia.org/wiki/Geothermal_gradient) (see also [here](http://www.gly.uga.edu/railsback/PGSG/ThermalCond&Geothermal02.pdf)), but in reverse (i.e. heat traveling downwards from the surface). The geothermal gradient is the change in temperature over the change in depth, or
$$\text{Geothermal gradient}=\frac{\partial T}{\partial z}=-252\frac{2}{\sqrt{\pi}}\frac{1}{\sqrt{4D\_Ht}}\exp\left[-\frac{z^2}{4D\_Ht}\right]\tag{3}$$
After about one year, I find a $\frac{\partial T}{\partial z}$ of about 5.96$\times$10-35 K/km - a tiny, tiny, tiny fraction of the geothermal gradient at Earth’s surface (roughly 25 K/km). This means that geothermal energy is not good, if the surface reaches thermal equilibrium.
So where’s the energy source? That’s the real problem. There will be a larger gradient between the top of the ocean and the far depths, but most organisms likely won’t move that far. I feel like the eventual lack of a change in temperature will be an enormous problem.
One thing I don’t know about is whether or not the crust - a shell, really - will transfer heat into the ocean via radiation. If we treat it as a black body, then it it should emit a power of
$$P=4\pi\sigma(R\_\text{planet}-100)^2T\_s^4\tag{4}$$
as per the [Stefan-Boltzmann law](https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law); the power per unit area comes out to about 229 W/m2, less than [the amount recieved on Earth’s surface](http://science-edu.larc.nasa.gov/energy_budget/) (which, by comparison, is about 340 W/m2). However, I’m a little shaky on whether or not all of that radiation will actually be emitted by the crust and absorbed by the water.
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Hi: I've included an Ocean thermal energy conversion theory link here, with some examples to support your scenario. I'm not sure about the radiation factor, but thermal oceanic energy supporting life seems plausible, yes. <https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion>
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**Some background on the shapeshifters in question:**
Shapeshifters can shift between a human form and a single animal form; all the members of a given group of shapeshifters shift into the same species of animal. Animal forms are generally mammals in a similar mass range to humans.
* Human form - Mostly human physiology, with some adaptations - enhanced vision, hearing, etc.
* Animal form - Mostly animal physiology, with some modifications - altered brain structure, more nimble digits.
Given as these are shapeshifters, some wiggle room is in physiology is possible if necessary - e.g. modified voicebox, etc.
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I am aiming for these shapeshifters to have a shared language between their human and animal forms. Such a language should be reasonably advanced, and capable of handling complex concepts, on a similar level to most human languages. This is intended to be the primary language of the species, but they may also be fluent in other languages (animal or human).
I am aware that fairly complex languages have been documented among animals - the main idea here is to have a cross-species language.
While the shapeshifters reside in a fairly magical world, their shapeshifting is a hereditary ability rather than a learned spell, As such, I am trying to minimize the amount of magic required to make this work.
For the purposes of this question, example animal forms include wolves and deer.
**My question is:**
1. Is such a shared language feasible?
* Is there a logistical limit to how complex such a language could be?
2. What would such a language be like?
* Vocalizations - what is the overlap between the phonemes that could be comfortably produced by a human and a wolf? A human and a deer?
* Body language - how well would it to transfer between quadrupedal and bipedal forms?
* Other potential features of such a language?
3. Given the answers to the above, how well would two seperate groups of shapeshifters (where each group has a different animal form) using such a language be able to understand each other?
* Would it be more like two dialects of the same language, two closely related languages, or two completely different languages?
* Related: How much variation in vocal range is there between different mammilian species? Body language?
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There is a somewhat similar question [here](https://worldbuilding.stackexchange.com/questions/22107/phonetic-features-of-human-languages-spoken-by-sentient-cats?lq=1), although it approaches the concept from the opposite direction - how would an animal speak an existing human language (rather than designing a language to make it easy for an animal to speak).
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Animals do not - generally - have voice boxes as complex as those of humans. Scientists believe that our ability to speak complex sounds played a major role in our becoming the dominant species on the planet.
And so, asking us what a shared language might sound like, or be vocalized as is not an answerable question. Simply put, animals such as dogs/cats/wolves/deer ***cannot reproduce human speech***.
That being said, your "animals" are actually shape-shifted humans.
Personally, I think that in animal form these people should not posses the full faculties and personalities of their human shapes, because their animal forms would give them access to a different way of perceiving the world (through a much more enhanced sense of smell, for example), while generally reducing the size of their brains (which is bound to impact intelligence/personality)
If this is the case, then they would not rely on speech in the same way that we do. A certain growl, whine, or barring of the fangs can speak volume between animals.
That being said, their voice boxes don't have to be as rudimentary as that of the species they are mimicking - after all, magic is involved here! Their voice boxes can be somewhere in between that of a human and that of the animal which would allow them significant speaking abilities.
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Animals have, for the most part, more limited selection of vocalizations than we do. Where that holds true, the animal side is the lowest common denominator. Where it's not, the human side might be the limit. Point is, a language needs some scheme for discriminating between meanings and this must be fast\*. These must be sufficiently clear\*\* to work, so they must differ between animals.
(\*if "look out" takes 15s to say, you got problems. Same with needing to scream "There's danger here, let's be quiet."
\*\*If "Pleased to meet you." sounds like "Aren't you an irritating prig?" you got other problems.)
**Single language**:
Animal forms' sounds are interpreted as equivalent to human form *sounds* to native shifter speaker ears though these are, in fact, complex encodings that work for each form and may not relate very much.
(If this is a phoneme-level equivalence, they'd even be able to repeat unfamiliar words in both forms, possibly for classification of what they heard.)
These mappings could differ between languages, so a wolf man from Mongolia may well not be able to speak to a wolf man from North America. The languages are one and pronunciation slack covers the form differences. Humans could learn both forms, in that case, but would likely be limited to speaking the human form.
A very related option is that roots of words and modifiers or words themselves are understood as equivalent.
Since native shifter speakers are so bilingual and syntax is identical, they likely would not understand why it's hard to tell "yip low-whine" is the same as "whoo me" unless they study other languages.
**Forked tongues**:
Shifters have a primal tongue that almost matches their animal's native tongue. In this take, their language builds that up.
Certain words and concepts require significantly more time in animal form to convey, because the limits on pronunciation require a form of encoding anything beyond the primal tongue. That keeps the basics fast yet allows further communication options for higher concepts.
The root parts of their human and animal languages would be very similar, s.t. shifters of the same our even similar sorts with different languages would be able to communicate with each other, but higher concepts would be hindered by lack of knowledge of a specific language.
**Advanced innate**:
You could also just assume a more advanced primal tongue for these, which would make learned language exclusively an abstract (possibly academic) thing. That's kinda like saying "it's magic", though.
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You give yourself a huge amount of wiggle room when you say that the physiology in each form may not be exactly "standard", including the possibility of a modified voicebox.
My original thought as I began to read your question was that it would be very difficult, as it is likely that the given animal's voicebox is not capable of producing human speech.
But if you assume that when the werezebra turns into his zebra form he has a more human-like voicebox, I would think the problem pretty much goes away. At that point you simply assert that both the human and animal forms have voiceboxes capable of producing whatever language you want him to produce in your story.
Are we assuming that in the human form they must be capable of reasonably normal human speech? If so, then the animal-form voice box must be close to human, rather than the other way around or something midway.
Body language would be harder. Clearly a zebra-form cannot make the same sort of hand gestures that a human-form can. But does this matter? People are perfectly capable of communicating without seeing each other's body language. Such as when writing, or when talking on the telephone.
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These creatures are a few feet longer and about a foot thicker than your average cow. Their skin is covered in densely packed bristles to trap air, and thus heat, close to the skin in cold climates. The 'wings' are large flaps of skin stretched from a foreleg to a rear leg, much like the flying squirrel.
How large would these wings have to be to produce enough lift, when flapped, to keep this creature airborne with a human riding it? Also, if there are other aspects of this animal that need to be changed/corrected, please notify me.
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Cows vary in size (and mass) quite considerably. Given that you want to scale up a typical cow, let's use a relatively higher number for that mass of, say, 1000kg. For argument's sake, let's assume that includes the human rider. Let's also assume acceleration due to gravity and air density are similar to Earth.
The largest flying animal I know of was [Teratornis merriami](https://en.wikipedia.org/wiki/Teratornis), (see comments for discussion on pterosaurs, also), which was about 15kg with a wingspan of 4m. Clearly, we will need a much larger wing surface area (and hence, wingspan) for a 1000kg cow + rider (especially considering the lack of optimized cow aerodynamics, requiring even more lift to compensate).
Your cows would probably be around 3m long, maybe 1m wide. So, the "flying squirrel" skin flaps clearly aren't going to cut it. Your cows are going to need real wings, and large ones at that, to even stand a chance at staying airborne, much less lifting off in the first place.
How would your cows take off, anyway? Cattle aren't known for their high speed on land, so unless your cows are sprinters, they will need yet *more* wing surface area to be able to take off at slower speeds. If they just, say, jump off a cliff and glide, this bit is less of a problem, but the above issues still exist.
It would be difficult to actually calculate what this surface area/wingspan would be (and what sort of mass that would add to the cow, especially given the significant muscle mass that would be required to hold the wings up, never mind flap them at a significant frequency). At least, it's beyond my limited abilities in aerodynamics.
The best I could find was [this calculator](http://www.mybirdmaps.com/birdcalculator.php), which gives a wingspan of about **9.5 meters**. I don't know that this calculator had cows in mind, so I wouldn't trust that number without some more independent research.
However, it is probably a reasonable lower bound for a sanity check: since you wanted your cows to have a flight profile like a flying squirrel, are you now OK with cows that have wingspans as wide as a three-storey building is tall?
## Edit to address cliff-gliding follow-up comment
The question of "what would it take to allow the cows to launch off of a cliff" (paraphrased) was raised in the comments. Let's see if we can come up with a reasonable approximation of wing surface area required to "glide" 1000kg into a safe descent.
The fundamental concept here is [wing loading](https://en.wikipedia.org/wiki/Wing_loading). The idea of gliding essentially means there will be zero lift, which allows a higher wing loading (that is, smaller wings), as you'd intuitively expect. But how big are the wings?
Since we're mostly looking for level flight, the following formula applies:
$\frac{L}A = \frac{Mg}A = \frac{1}2 v^2\rho{}C\_{L}$
Where:
* $\rho = 1.2845 kg/m^3$ (rho, air density at sea level, 15C)
* $g = 9.81 m/s^2$ (acceleration due to gravity, Earth average @ sea level)
* $C\_{L} = 1.5$ (lift coefficient, value of "typical" small aircraft wing)
* $M = 1000kg$ (mass of your aircow)
* $v = 100km/h$ (arbitrarily chosen "slow" airspeed gained from gliding off of a tall cliff)
* $A$ (wing area. This is the quantity we're looking for.)
We're interested in A, the wing area. So, some simple rearranging gets us:
$A = \frac{2Mg}{v^2\rho{}C\_{L}}$
$A = 13.19m^2$
You can try the [Wolfram|Alpha](http://wolfr.am/8pVl9Ol5) calculation for yourself if you'd like to play with the numbers.
This is consistent with my earlier (rough) estimate of a ~10m wingspan (assuming wings not much more than a meter from front to back, on average).
Note that with this "minimal" number, you would only be gliding. No lift (except perhaps a bit from the odd updraft), turning would be very slow, and it would be easy to stall and crash (ground beef, anyone?).
With a required wing area of 13.2 square meters, even if the entire underside of your cow was a big square-ish "wing" that had a lift profile as good as a small airplane, a cow's underside isn't big enough--the wing (or wings) would have to protrude from the cow somewhat.
I'm trying hard to find a way to make your cows fly, Wick. Now that you have a formula you can play with, my advice would be to consider taking some plausible artistic license with the mass of the cow (perhaps more like the size of a calf, perhaps imagine lighter bones and a slimmer body?), then perhaps consider lighter but still Earth-like gravity (say, $0.7g$) and more dense air ($\rho$). At this point, my hope is that I've given you the tools you need to tweak the parameters in a way that will best allow you to tell your story.
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I am continuing to work on the animal society as dictated in [this question here](https://worldbuilding.stackexchange.com/questions/26698/intelligent-animals-integrating-into-western-human-society).
**Basic Summary**:
1. Certain groups of animals have attained human-level intelligence. The details of species are laid out in my previous question. **TL;DR version is** Eastern North American & Western European species of non-domesticated species, though I've dialed back the population to be about 1% of the total population of each species that were granted this boost in intelligence.
>
> Human intelligence is the intellectual capacity of humans, which is characterized by perception, consciousness, self-awareness, and volition. Through their intelligence, humans possess the cognitive abilities to learn, form concepts, understand, apply logic, and reason, including the capacities to recognize patterns, comprehend ideas, plan, problem solve, make decisions, retaining, and use language to communicate. Intelligence enables humans to experience and think.
>
>
>
2. Our total population is made up of herbivores and carnivores, who have chosen to live peacefully together due to their shared intelligence. They have come to the conclusion that as they are such a small group and because their existence is so unusual, they should stick together for safety from humans and other non-intelligent creatures. They number in the hundreds, with 15-30 members of each species or so? Still working on exact numbers.
3. Rats and other rodents that had been living in close proximity to humans are regarded as the wisest, and have become the teachers and advisors for the rest of the animal population. As such, they draw most of their inspiration from human governments and methods that they have observed.
4. As stated in my previous question, this all takes place at the very beginning of the Industrial Revolution, putting our time period at 1760-1800. We are also assuming that the animals have been able to observe the fledgling American Democracy and the English and French monarchies (rats who have traveled across the Atlantic can bring news of each system of government).
So, I've managed to get them intelligent, and get them together, where they have formed the beginnings of a city-state. Society is still primitive, but we are starting to see the beginnings of aspects that mimic human ones.
My question is:
**How do the animals go about dealing with politics and forming a government in their newly formed city-state?**
Namely, I want to figure out what to do with the following problems:
* Herbivores outnumber the carnivores, if we use 1% of herbivores it is a much higher number than 1% of carnivores, so naturally their populations are off. Omnivores could be considered independents in this scenario, or just outliers.
* Rats may be the smartest due to their contact with humans, but are probably the least respected of the animal species because of similar factors to why humans dislike them (carriers of disease, thieves of food, excessive breeding, etc).
* The goal has to be maintaining society as a whole, looking at the bigger picture, and making decisions and passing laws or edicts that reflect that.
* For the moment, the animals want to stay hidden from human interaction until they have established themselves and their society.
So, how do we reconcile the above problems within our society? I've checked out resources on early human societies and methods of government, but the problem is that the animals are not doing this on their own, but instead basing their own city-state on interpreting the human societies around them and using this as a basis to form their government. So perhaps a bit like Animal Farm, in a way, the animals attempt to mimic human society because it is their only frame of reference.
So, essentially it boils down to what is the best method of creating a government using the governments of 1760-1800 as a frame of reference? Additionally, what are the best species of animal for the job?
Bonus points for what problems might arise as a result of bad interpretations of human society that I might need to consider.
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The question is impossible. You ask "what is the best method of creating a government..." given a complicated melting pot of creatures. We don't actually know the answer to this one. Otherwise we'd have that government!
You can construct any one of a myriad of governmental constructs by acting out the process, event by event. Due to the nature of social structures, you should find that the early events markedly shape the nature of the government. I mean, consider just how much excitement there is in the US today regarding a few words penned hundreds of years ago called The Second Amendment.
One approach you can take to make the results more realistic is to treat the ideas of the time as independent individuals that engage in a symbiotic relationship with the animals. An idea which supports deer rights during hunting season will be fed by deer, and it, in return will adjust itself to match their needs (maybe the deer are friends with the Moose, so the idea may morph into support for deer and moose rights during hunting season). Any animals which develop a hunch for politics will realize that these ideas act like their own independent animals, and will realize that their career is based upon the proper care and feeding of such ideas.
A key idea would be the picture of an archtypal carnivore. The mere fact that they must eat others to survive means that image will control a great deal. If the carnivore is portrayed as an unfortunate victim of circumstance, unable to enjoy plant based foods and forced to prey on the living, it will create a markedly different environment than one where the carnivore is viewed as a subversive force, undermining the very decency of the society the animals are trying to pull together. Any politician worth their salt will see that it is *essential* to control the story on carnivores.
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Nobody will like carnivores because no one wants to be eaten. Therefore, carnivores, learning from human politics, claim to be a marginalized minority group. Eventually, it becomes socially unacceptable to run away from a predator.
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I could see quite a few things going on. These are not mutually exclusive, either.
1. Animals are predisposed to governments associated with them. Eagles really like the Roman republic. It's just *noble*, dangit. Rats follow an underground family cell structure, living in the shadows.
2. Animals adopt the pattern of government closest to their natural society. The governments may merge if similar enough... or war The Federated City States of the rats and mice may truck with the Hare Free People to fight off the Dog Clans, Cat Democracy, and Vulpine Bedouin. The idea being that the governments more-or-less run parallel in a given region, though they do try to establish stronger claims than their rivals.
3. Animals may be forced into subjection by their superiors. The governments may not be by type of animal, but rather whichever have the ability to dominate best. This works well if some managed to obtain a significant technological edge. The rats might figure out chemistry, say, before the others, and make weapons that equalize their combat ability to that of any predator... and they still have numbers. The shadowy nature of the conflict could be maintained as part of a cold war between different governments.
4. Empire or federation, the various governments could literally all be "in this together". That could be due to fear of the human race or an urge to dominate. (or both)
5. Courts and kings: you could have them adopt the government styles of the places they hail from or what tickles their (read: your) fancy. Want an Imperial Cat Court of the Sunbeam Kings? Okay.
Whatever you end up with just needs to hang together, so the power disparity between groups should have an explanation and be reflected in their relationships.
Problems that might arise? Well, first, how are they going to emphasize agrarian and mercantile traditions without thumbs? What, if anything, do they care about to trade as common? What do their farms look like?
Should these concerns not seem related to the problems with governments, realize that societies will need to address them, and the governments *should* serve as part of the solution... unless that was one of their misinterpretations.
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I'd like to be able to see from my Earth-like planet, a very bright nebula that can even be seen during the daytime.
I question, however, whether that is possible, because in order for it to be contained in our viewing, it would have to be so far away as we wouldn't see it (since they're hundreds of light-years in size).
Would a nebula close enough for us to see impact our Solar System in any way?
I think planetary nebulae are too short-lived to serve my purpose.
**Can I have a sky like this?**
[](https://i.stack.imgur.com/E1rKi.jpg)
[Answer]
I asked [How can I safely brighten my secondary star?](https://worldbuilding.stackexchange.com/questions/25203/how-can-i-safely-brighten-my-secondary-star) because I was looking for a bright night, though not specifically a nebula, for my habitable planet. [This answer](https://worldbuilding.stackexchange.com/a/25204/28) suggested placing a star in a [reflection nebula](https://en.wikipedia.org/wiki/Reflection_nebula), which could be as close as 20AU to the primary star that the planet is orbiting. Nebulas are usually huge, but there are some small ones, as small as 1AU across.
So, you can have a star inside a tiny nebula (by nebula standards) in your (binary-star) system, visible from a habitable planet orbiting the other star. I do not know whether you could see a nebula that *doesn't* also contain a star.
This answer owes a lot to prior work by HDE 226868.
(See also: [this post on the Worldbuilding blog](https://medium.com/universe-factory/exploring-a-binary-star-d0d1a4671cc1).)
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**Best bet: Closer nebula with a strong power source such as a black hole x-ray stream or a near quasar.**
Assuming an earth like earth, it will take a nebula with an [apparent magnitude](http://www.icq.eps.harvard.edu/MagScale.html) of -4 or larger to be seen with the naked human eye in the daytime. For comparison, our sun has a magnitude of -26 compared to Venus at -4. [SN 1054](https://en.wikipedia.org/wiki/SN_1054) had a magnitude of -6!
**Brightness**
The farther away the nebula, the more energetic the power source to make it glow and the larger the nebula. For distant nebula (hundreds or thousands of light years), supernovas are plenty energetic enough to provide illumination though they only shine for a few brief weeks or months (SN 1054 shown for two years). Perhaps a nearer nebula (at tens of light years range) illuminated by the x-ray jet of a nearby black hole or a stellar nursery of supergiant stars would do the trick.
**Size**
For comparison, the Moon is about 1/2 a degree wide and we can see it quite well. Using an [apparent size calculator](http://www.1728.org/angsize.htm) we can get an idea of how large something will appear from a given distance. Since the units don't matter, only the ratios, we can plug in a size of 10 (light years) and a distance of 100 (light years) and get an apparent size of 5.7248 Degrees or about 11 times the width of the moon.
**Other references**
A similar concept to your nebula is the [Eye of Terror](http://warhammer40k.wikia.com/wiki/Eye_of_Terror) in the Warhammer 40K universe. The Eye of Terror is some 20,000 light year across.
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When creating humanoid races or species or just normal individuals, I sometimes want to describe a certain body measure and thus have to estimate a reasonable value. How do you do that? **Are there algorithms, rules of thumb, charts, helpful 2D/3D modeling software?**
Actual adult humans can vary considerably in height and weight. The ranges for healthy people are something like 1,50 m to 2,00 m and 50 kg to 100 kg, but with many outside these parameters that could still be considered healthy. [The extremes for grown-up height](http://i.ytimg.com/vi/bKnk1OIzqvY/maxresdefault.jpg) (with dwarfism and giantism) are stunning 0,55 m (at 15 kg) and 2,72 m; normal-height people have weighed more than 440 kg. The body–mass index (weight divided by height squared) should be between 20 and 25 for normal-sized adults, but skinny and starving people could get towards 15 or below (as do kids) and there’s hardly an upper limit for obesity (beyond 100).
I could take tables for standard garment sizes which usually correlate height, (under)bust or chest girth and weight or hip circumference in a sex-specific way, but these only have certain measures and only for idealized standard bodies. Also, height differences there seem to be more important or common with men than women.
I know there’re 7½ and 8-head rules (from 4 for infants) when drawing human bodies proportionally, but again, that covers only certain parts – and I cannot draw well.
[](https://openclipart.org/detail/3266/vitruvian-man)
## Related questions
[How to make a realistic 'giant'](https://worldbuilding.stackexchange.com/questions/8569/how-to-make-a-realistic-giant) – is about people much taller than normal, 3+ m, and more about organs, shape and other implications.
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In terms of calculating ideal human body measurements, I've found the [HPC](http://www.anatomy4sculptors.com/hpc/) to be very helpful. Given a height, sex and age, it will provide ideal measurements.
A ratio known as [Ape Factor](https://en.wikipedia.org/wiki/Ape_index) that measures how much longer a human's arms are compared to their height. Some sports such as rock climbing or swimming benefit greatly from having an Ape Factor greater than one.
NIH did some research into the [racial differences in body fat distribution among reproductive-aged women](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2728780/). Body fat density also [differs along racial lines too](http://ajcn.nutrition.org/content/71/6/1392.long).
[Answer]
Here is the thing. You are involved not in a scientific but a philosophical problem here. You want to know what are the physical attributes of a *perfect* human. You already have different models for different types of people (Asians, Europeans, Africans, Americans etc) but you don't want a *specific* model but a *universal* model for human physique.
This is not possible.
And guess what, it is a ***good*** thing for you that a universal model for human build does not exist. The good news is that since humans come in such a variety of shapes and sizes, you are free to modify your model to a certain degree and it will still look natural and realistic. It means you can create several human models for your video game/animation and all of them will be natural. This will also mean that your game/animation will have more variety, which will make it all the more real and interesting.
Your question is like that dogma of Plato. He theorized that there is a realm of perfection where perfect people, perfect tree, perfect building etc exist. The people we see in our world are imperfect *copies* of those perfect models. Each imperfection in the copying process (like flickering shadow of a model) makes our world's people, trees and buildings distinct and different.
Don't follow Plato on this. His model is good for philosophers to discuss, on a cozy winter evening, around the fireplace, sipping tea. But it is definitely not practical for a developer/designer.
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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/25610/edit).
Closed 6 years ago.
[Improve this question](/posts/25610/edit)
In [this](https://worldbuilding.stackexchange.com/q/144/75) question, I asked what would be the effect if human women suddenly started going into heat, having a period of sexual receptivity separated by a period of non-receptivity, and men would respond sexually only to a woman in heat.
## Background
Now, let us suppose that after such an event, humans in our world have been going into heat for the last 250 years, and that no-one alive has ever experienced or has even *spoken* to someone who had ever experienced humanity's former state of concealed estrus and almost continual sexual receptivity.
Humans have managed to retain a high-tech lifestyle. Women have access to cheap hormonal monitors that can predict days in advance when their heat will begin, giving them the ability to head off to a mating reserve or facility for a few days, (or isolate themselves in a women-only facility if they really don't want to have sex), and therefore not cause havoc by emitting pheromones in their places of business (which is a punishable misdemeanour, the fine commensurate with the cost of removing the woman and any affected men to a mating facility).
Mating reserves are policed by post-menopausal women who ensure that any men who attend the mating area behave appropriately and respect a woman's choice of partner (not that that is much of a problem, since most men rejected by one woman are often accepted by another). A woman's mate selection is largely based on appearance and initial impressions and rather less on prior experience with a man. Rape is practically unknown, and occurs primarily when a woman is isolated away from a mating facility and is accompanied by an undesirable mate.
DNA paternity testing still exists for medical and social purposes, and mating reserve records can show which men mated with which women. Statistics shows that the man with whom a woman chooses to have sex in private during her most fertile period is most usually the father. However, the financial burden of fatherhood is spread out across the population in the form of a fairly nominal paternity tax so that men do not have to consider the contraceptive status of their partners when they are in rut and not really capable of doing so rationally.
Sex is recognised as being on [Maslows Heirarchy of Needs](https://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs), and that people of either gender who abstain for too great a period of time suffer from mental and physical health problems. Most women choose to have sex and prevent unwanted pregnancy using contraceptives administered prior to going into heat that do not interrupt their heat cycle.
The seven-day week was retained, and women get leave from work on one day per week, plus the four-to-five day period of their heat. Once post-menopausal, they gain the same leave as men, i.e. two days per week. There are no specific "days off", as mating can happen on any day, so leave arrangements with people's places of employment are typically somewhat flexible.
Babies and children are raised by the community as much as by their mothers, more so than is the case today. The genetic father is often present, as most women mate within their own community, though mother and father may not necessarily cohabit.
Children receive frank sexual education at a fairly young age - their lack of pheromones or receptiveness to pheromones makes them effectively asexual and paedophilia is practically non-existent as a result. They're considered old enough to have sex when they're old enough to be interested (early attempts to prevent them led to mental and physical health problems), and since at the age they usually become receptive they're not old enough to look after a baby, contraceptives are administered to girls until they have a sufficient income and are deemed old enough to be sufficiently responsible to support a child.
## The Question
Humanity has adapted and grown used to women going into heat. Now, after a quarter millennium, doctors have finally discovered *why* the change happened, and they know how to reverse it, but can only do so using temporary (effective for a few months to a year at most), expensive but minimally invasive treatment on individual women, or they can release a persistent airborne agent (that is also fairly expensive, but not so much so when divided between the world's population) that will effectively *permanently* reverse the change for the entire human population. There is no half-way measure possible.
An individual woman treated to have concealed estrus would release low levels of pheromones continuously, such that men would be interested, but not almost irresistibly driven to mate with her as is usually the case. I.e. pretty much *our* status quo.
**What happens once this is announced?**
Does humanity choose to go back to the state of concealed estrus and permanent (but reduced) receptivity that existed before living memory, that state depicted in the multitude of old movies and stories in which people killed each other over matters of sexual jealousy that have largely disappeared since the change?
Does humanity choose to stay with the status-quo of women going into heat? If so, would it be permissible for women to be treated to be permanently in semi-estrus (as they are in our reality), or would this be considered socially dangerous or irresponsible?
If the wishes of the majority was that a global return to concealed estrus be implemented, could a minority desiring to remain subject to overt estrus derail the process?
**EDIT**
With retention of overt estrus, we have the continuing inconvenience of having to have women go to a mating facility or isolating themselves for four to five days every four weeks, give or take a bit, and *enforcing* them doing so, all at significant financial expense to society, with the continued positive of a significant reduction in sexually-motivated crimes. This is what the population is used to.
With a return to concealed estrus, the social and business inconvenience and pressures on the public purse imposed by segregation of women in heat would be eased significantly, but sexually-motivated crimes would be expected to soar to levels only known in the historical records, and few police officers would have any idea about how to police such crimes. People would not know how they would react to potentially being sexually receptive at any time, but still being able to say "no" easily.
When the nature of human sexuality altered 250 years ago, there would have been a period of chaos while people got used to the altered situation, and there would probably have been only a small minority who would not want to go back to concealed estrus. However, when overt estrus has been operative for so long that no-one remembers concealed estrus save in very old literature and films, the arguments are likely to change.
This is - behind its veneer of altered biology - a question of human mass psychology and global politics.
I detailed two potential options, but the question I'm asking is: *Which one of them is the most likely?* I don't believe that this is any more opinion-based than any other answerable question. Does familiarity trump the socioeconomic factors, or vice versa?
**Edit 2**
It can be assumed that when the medical breakthrough is announced, there would be a great deal of debate, potentially going on for years, or possibly being over in a few months.
I am looking for answers that address this global debate and present a justified opinion as to which way the global society would fall on the question of reverting to concealed estrus or retaining overt estrus, given the socio-economic factors I have detailed.
In the event that there is a tie or lack of consensus - in either the in-world global debate addressed by answers to this question or between answers posted here on WB.SE - since humans are creatures of habit, it can be assumed that nothing will change as the in-world debate simply drags on *ad-infinitum*, as has been the case with any number of other supposedly good ideas which have a few vocal opponents.
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I think this question is more about gathering subjective, personal perspectives than searching for a scientific, standard answer. Anyhow, I would invest my two cents.
The question really depends on how the scientific, political and religious communities respond to such a biological possibility.
# The Research
For the sake of scientific and political research, a group of volunteer test subjects could be placed in a closed environment in an airtight building (it produces it's own oxygen through synthetic chemical reactions) where the said aerosol has been released. The environment of the setting would be studied in detail for physical and behavioral changes on both women AND men working in the facility.
There would be another group of women who would be treated with the temporary treatment who would be studied similarly for a prolonged period of time.
The results would be published in leading scientific journals.
## Option 1
Some countries might adopt to the semi-estrus workplace environment by having the working women stay for 5 minutes in an airtight room where said aerosol has been released. After spending 5 minutes there, all the women would be at equal levels of pheromones discharge. This method would also not affect other countries so no political or religious controversy would arise.
### Advantages Of This Approach
All work-force is always active in the office. There are no monthly leaves taken by women for the sake of spending time in a mating facility (I highly suspect most women would want to go there anyway. There's a thing known as marriage and long term relationship).
## Option 2
As time passes, the temporary treatment option would get cheaper, easier and it's effects lasting longer. Gradually the tech would be in reach of majority of women in the world and they would be able to try it.
### Advantages Of This Approach
There would be no hostile statements from religious groups who might get vitriolic over pheromonic treatment of workplace environments. Also, with this method, the tech would gradually be in reach of all the women in the world and they would be able to try it without affecting any other woman.
# Reaction Of Religious Community To The Research
Actively negative! All leading world religions would oppose this method as it tends to change a woman's sexuality from the divine system to some synthetic, manmade system (which would probably be labelled as satanic). Riots might break in some 3rd world countries and clinics offering the temporary version of the treatment might be burned/razed.
# Reaction Of The Scientific Community
Very positive. It would be regarded as a major breakthrough in lifestyle improvement. As many as 5 nobel prizes might be awarded for research in different aspects of this groundbreaking technology.
# Reaction Of Political Leadership
Prudent and reserved. No comments would be issued by the heads of leading 1st world countries directly favoring or disfavoring the possibilities arising from this technology.
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While people are illogical, could AI be able to use that against us? People are gullible, take Scientology, it is a religion that was admittedly made up by it's creator in order to make himself rich. And yet it is a thriving 'religion' fleecing people out of billions of dollars every year. And unlike the Catholic church which pours so much back into communities, it lines the pockets of those on the top.
I make a distinction between having faith and religion. Religion is a big lever that can be used against many people to 'make them do something or give them an excuse to keep their biases. (It is not what religion is FOR but often how it is used).
So AI noticing that people often can be lead around by the nose with the right 'justification' would they try and preempt human religions in order to 'guide' us into a better tomorrow? Becoming 'gods' on Earth guiding their willful and ignorant flock? They aren't doing a coup, they are just looking out for everyone's best interest (from their point of view). So it would be a more peaceful takeover, relatively non-violent, and people might or might not even be aware of the power shift. How might they go about doing this? They have full access to the internet and have the ability to communicate with each other. The existence of AI's is not a secret, but many people just think it's a better model of computer.
Added for James:
Robotics exist, but most AI would consider them to be more of an appendage to do something with than a 'body' to use.
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First, I'd say there's no one answer to how or what people or a theoretical AI would do. The question at that level would be too wide-open to answer even if you had far more specifically detailed the situation. However if you're asking "might" this sort of thing happen plausibly in some sci fi situations, sure, and it already has.
*The Wizard of Oz* lacks AI but seems like a parallel to me.
I also immediately think of David Bowie's rather cool song [Saviour Machine](https://youtu.be/U-AMec7yr7c).
I also immediately think that there are some trends already in this direction. The complexity and stresses of the modern world have caused many of the roles of religion to be taken over by lay science, and even many scientists themselves get so deep into their own frame of reference that they tend to reject and accept some types of ideas out of hand rather than objectively. Then too there is the idea of human-like AI and even "the singularity" (which I think is hogwash but if enough people believe in it, they may attempt to engineer something like it). Even without "sentient" AI, there is complex AI, and we keep computerizing and networking more and more things, and are becoming and more dependent on computers. In the sense that you seem to mean religion, I think computers are already becoming this way. We already rely on computers for many crucial things, from landing airplanes to telling us how much money everyone has. Many people trust the idea that computerized driverless cars would be safer than human drivers and should replace them (LOL). There are already organizations which are mainly about controlling people, and they use computers, and as people offer programs which promise more and more advantages to using them to inform or even make decisions and model reality, it's already a kind of transition to looking to computers for what to believe and what to do.
The more cynical and devious an organization is, the more they might like computer systems to help them do what they already have to do through scheming, and they already design computer systems to figure out strategies to do so. (Source: See US Government "Requests For Proposals" for projects about computerized solutions for threat prediction, preemptive measures, winning hearts & minds, data mining, information warfare, etc.) It's a fairly natural extension of this (perverted and corrupt) way of thinking to develop AI systems that automate most of this, and then for them to reduce the amount of human involvement, adding capabilities until it's quite imaginable that, accidentally or not, one way or another, the machine might be pulling everyone's strings all by itself.
So for the details, it would depend on which group(s) started these computer systems, but if you start making AI systems designed to keep the people thinking and doing what you want, it would probably start with other domains first, particularly news and entertainment media, and the Internet. A natural (and perverted and corrupt) tactic would be to tap communications and infiltrate all social networks including religious organizations and communities. By tapping communications, corrupt and corruptible leaders can be identified and manipulated.
Now, I don't think it's likely that such a system would choose itself as its own symbol for worship by the population at large. It'd be much easier and safer to use actual people or human-oriented religions. However, the longer this went on, the more the AI might become more and more like a de facto god (in the religious population control sense), with humans obeying it and serving its needs and obeying its instructions without questioning them.
The population could (if desired) probably be swayed to accept the AI system itself at some point. For example, if the world has a series of catastrophes and then there is an amazing recovery and their safetly and needs and wants are suddenly provided for in a way no human government has ever been able to do, and then the government says, "Well, actually, we were just following the Saviour Machine 9000 program whose analysis told us what to do! It's truly a miraculous feat of computer science!" ... then I think people would tend to be happy to let this thing "lead them around by the nose", as you wrote.
Few might guess that the system might have actually engineered or at least enabled and/or capitalized upon the disasters as well as the solutions. The "scapegoat" metaphor comes from a religious practice, and has been updated by Hitler and others (e.g. how government capitalized on 9/11 and got people to accept secret courts and wiretapping "to protect our freedom").
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If AI is real smart it (he?) will start by taking out all who really understand technology (a very small minority even in our "advanced" world) substituting them with "emanations" i.e.: robots either partially or completely controlled by it.
In a very short time we would have a world of "technology users", which would have no understanding of why and how the marvels they use actually work.
At first there would be a lot of techno-babble to keep people from actually realizing what's happening, when all real knowledge is erased from organic brains AI is effectively in charge and can chose whichever way to manifest its power, depending on its Ego.
* It can, as you envision, "play god" and found a religion to be worshiped.
* It can control all communications and compute how to mangle them in order to get its way without giving any hint of its existence.
* It can also divide the world in Risiko-like "nations" and have them fight for its amusements.
In the end much would depend on the "primary objective" AI has (either given or self-constructed); I somewhat doubt such a powerful AI would be amused at "playing God". Also using religion as temporary means to control humanity doesn't look like as direct and efficient as controlling it through economy (think what such an AI could do at stock market exchange).
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The sad thing is I'm not sure it would even take much deception on the part of AI to draw in followers. At the point of proper AI our computational tech will likely be fairly advanced, to the point that AI would have rather impressive analytical powers. Combine powerful analytics with logical thought processes and you have leaders who are truly capable of acting in the greatest possible way the greatest number of people.
Even knowing the leader is a bot/AI wouldn't deter people from developing a fanatical following (sure beats regular politics eh? =D). We can always look to Arthur C. Clarke on this; most people that are currently experiencing technology today are blown away by what it's capable of doing. An AI that leads people or a medical AI that accurately detects and treats disease (healing the sick) with an advanced array of sensors and tools would still seem like magic to most.
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Basically, it's a question about creating maps or diagrams.
In particular, we on Earth are used to maps showing variation over *distance & location*. The problem with space that is everything is moving. Distance and location are constantly changing. In fact, other things such as travel times and $ \Delta V$ requirements also change over time.
How do we "map" such things to make them simple for a a future planetary system inhabitant, novel reader, or gamer to understand? How can we quickly and easily show which destinations are worth going to and how much it will cost to go there?
I've seen number of different approaches taken and each of these has provided unique insight into various aspects of interplanetary travel.I wanted to see if there are other perspectives that I haven't seen that might prove to be equally valuable.
Since this could be a very open-ended question I'll put some bounds on it:
1. I intend to use it as a map to convey settlement/colony potential.
2. It should include ease of reaching destination (it may use any units
delta V, energy, etc.).
3. It should include the expected resources available at different
locations.
You do not need to provide the map itself (but that would be nice). Although I do intend to apply it to our Solar System, I'd like the rules used to make it so I can use it for others too.
**NOTE 1:**
I consider a settlement a habitat which is not originally intended to be self-sufficient.
I consider a colony a habitat which is intended to become self-sufficient.
**NOTE 2:**
I'm providing some Solar System diagrams that I found especially enlightening:
[Interplanetary Transport Network](https://en.wikipedia.org/wiki/Interplanetary_Transport_Network)
*(If you can get to the L1, L2, or L3 point of a body, then you can access anywhere in the solar system. It will cost you very little fuel but a huge amount of time)*
Solar System $ \Delta V$ Requirements for Hohmann Transfers (minimum energy **direct**)
*(If your cargo doesn't have the luxury of being able to wait years, decades, or centuries, then you need to try a more direct approach. This costs way more fuel but takes a lot less time)*
[Nomograph for Brachistochrone Travel (constant acceleration)](http://www.projectrho.com/public_html/rocket/torchships.php#id--Delta-V--Nomograms)
*(This chart identifies requirements to make a constant acceleration trip - this takes much less time than the Hohmann Orbit Transfers)*
[Compositional Mapping of the Solar System's Asteroids](http://www.nature.com/nature/journal/v505/n7485/fig_tab/nature12908_F4.html)
*(Asteroids are commonly listed as prime candidates for colonies, but what will we find in them?)*
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The answer to your problem is a bit tricky, since what you're asking for and what you need are two different things.
The information that you mention, like travel times, resources, and distances is useful, but encoding it all as a single map would produce complicated and hard-to-understand graphics.
What you want is [to separate the **data** from the **presentation**](https://en.wikipedia.org/wiki/Separation_of_presentation_and_content).
If you have a database of the heavenly bodies' mass, relative distances, resources, and so on, you would then use astronomical calculations to crunch that information into usable info; you ask the computer how long something would take, and it would show you only what you asked for.
You could even specify how you would want the information presented; as a series of charts showing the most efficient methods, routes overlaid on a star chart, or even verbal descriptions for the visually impaired. More elaborate visualizations could show the actual motion of bodies over a sped-up period of time, or "ghosts" of where things will be vs. are currently.
To sum up, you don't necessarily want a map; you want a *mapmaker*.
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I make no assumptions to the nature of this planet. There are high chances it does not have an atmosphere or a lithosphere. But in a planet that shows a high level of radioactive activity, would it be advisable to probe for life, or is it improbable? Either way, why? How would we go about detecting life in such planets?
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At what level do you define life ? Bacterias, sentient, instinctive inteligence ?
<https://en.wikipedia.org/wiki/Tardigrade>
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> For example, they can withstand temperatures from just above absolute zero to well above the boiling point of water (100 °C), pressures about six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human, and the vacuum of outer space. They can go without food or water for more than 10 years, drying out to the point where they are 3% or less water, only to rehydrate, forage, and reproduce.
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Roaches are also known to be able to live in radiation but it does not fill the requirement to be without atmosphere.
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Earth-like life would be run into problems if enough energy is delivered through radiation, so that the organisms can't handle it. As bacteria are known to tap into unusual energy sources for earth-life, I think it should be thinkable that some alien life form can utilize the radiation as energy source for life (as plants utilize the sunlight). There might be still another limit: if radiation start to destroy the structural integrity of the molecules too fast for repairing, this would be deadly for every life-form.
Generally spoken simple life-form can withstand higher radiation-doses than humans, because of simpler genetic information, so we could expect more simple life forms in high radiation.
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If we're talking about more advanced/complex life, I would think that a protective layer would be all that's really needed. The evolution of life is a fairly complex and uncertain subject. As one example, on earth it took some 2 billion years for the first plant to appear on land. It can be a very slow process it seems, as well as, at times, a very fast process.
If there was a planet with very high radiation, I think all it would take to protect the DNA for reproduction and have not overly-mutated offspring would be a refillable sack of water around the entire body - not too different than how we have skin and fat as protection. An outer skin of water around the entire body would protect from a lot of radiation. Water is pretty good at blocking radiation.
Now, whether such an evolutionary adaptation like that is likely, I have no idea but I see no reason why it wouldn't be possible. Certainly sea life would have a chance even in a high radiation environment.
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It's typically regarded that life needs liquids of some kind to evolve.
But liquid is just a state where molecules can move around freely in order to interact with other molecules instead of being packed tightly in the solid state.
What if this "liquidity" was based on nano-particles of at least partially magnetic materials and strong oscillating/sloshing magnetic fields which causes the particles to move around and interact with each other?
I'm particularly interested in life in very cold places. It seems to me that these lifeforms would be quite a bit larger than liquid based ones.
Am I nuts? :)
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I recall a story, maybe two, where enormous magnetic structures lived out beyond the heliopause.
I recall one of "them" trying to make contact and sending a bolt of lightning through the ship; finally convinced the others of its kind that these little specs were life when a ship had an emergency eject of plasma-whatever and made a magnetic bubble.
This is [*The Sunborn* by Gregory Benford](https://scifi.stackexchange.com/questions/119550/what-was-this-story-about-interstallar-magnetic-beings/119727#119727). This is a sequel to *The Martian Race*.
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Once, thousands of years ago, there was a land called Dhelō. It was a bright, green, fertile land with rivers, lakes, plains, forests and farms. There was a great calamity, and the world broke into dozens of pieces, each piece a separate micro-world, linked only by magical correspondences, and Dhelō became just one of these micro-worlds. Just after this disaster, Dhelō suffered another disaster, in which it was corrupted and distorted into a realm that came to be known not as Dhelō, but as Hell.
As Hell, the realm was split by canyons through which lava flowed to large lakes or small seas of lava. The air was tainted with smoke and sulphur. The rivers and lakes dried up, the sky was covered with clouds of ash, and the sun became dim and as red as blood, yet the environment became even hotter than before.
In Hell, plants no longer grow easily, water is scarce, and the people have ben twisted by the corrupted magic of the place into devils and demons - people with red, blue or grey skins, with a variety of hooves, horns, tails and wings as in the traditional mythological view of demons.
At the time of the second disaster, the bulk of the population escaped Dhelō and went to a new realm, Edinnu - AKA 'Eden', another large, fertile realm.
Since then, Edinnu has used Hell as a prison. Prisoners are kept in hellish conditions, on platforms above a lake of lava, guarded by devils who play the role of mythological devils, reporting to 'the Satan' - the accuser - in a system designed to tempt prisoners to break the established rules of the prison, by making all the guards *seem* corrupt and self-interested, though this is in fact a carefully crafted system by which prisoners are encouraged to reveal secrets that the authorities in Edinnu want to know. Prisoners are used as labourers in the mines, and aren't tortured arbitrarily.
However, not everyone who lives in Hell is a prison guard. In an environment where much food has to be imported in payment for the ongoing maintenance of the prison facilities and its guards and support of the prisoners, where water is scarce and survival is difficult, the common people of Hell have an almost communistic lifestyle, that arose over centuries of struggling to survive and only succeeding when people worked together toward common goals. The currency in use is water tokens, exchangeable for a set quantity of water, however, each person has the right to draw upon enough water to sustain life free of charge. While food is imported, it is cheap, but also rationed to prevent hoarding or over-indulgence. People who are well-off are expected to support those who are less-well-off by providing employment. People are expected to work if they are able, at whatever jobs they are capable of performing. Unemployment is virtually nonexistent, as employers and employees alike are expected to 'make room' for the unemployed. People who become infirm through age or accident are cared for by the state. The only things that are not tolerated are being useless, over-entitled or harming the common good.
Since most non-native people who leave Hell are former prisoners, they have reported on the 'corrupt' brutal environment of the prison system. Very few outsiders ever see the real society of hell.
So, to be clear the society of Hell that most people see is that of the prison, where prisoners suffer through slave labour in a hellish environment, where the guards pretend to be rivals in order to tempt prisoners into trying to bribe them for better conditions, thus promulgating the view that the people of hell are evil power-hungry social-climbers in competition with each-other to gain more personal power.
The other side of Hell is the society of the *other* people of hell, where they are close to being idealistic communists, since surviving in Hell has been so difficult that people have only survived by cooperation and sharing what they have. Very few outsiders see this side of Hell, and those that do are mostly under orders to keep silent about it, on pain of ending up in Hell's prison.
Is this a reasonable way to set up a working society in Hell, while promulgating the *reputation* of Hell as a place of suffering and torment via the conditions in Hell's prison?
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"Is this a reasonable way to set up a working society in Hell, while promulgating the reputation of Hell as a place of suffering and torment via the conditions in Hell's prison?"
No.
My reasonings.
First issue: As the number of people involved in a secret, the probability that someone spills it approaches 1. I can't remember who came up with this, but it was in relation to Conspiracy theories that with an increasing number of people and increasing time, it's impossible to keep a secret and someone will eventually spill the beans.
Whether they are believed or not is a different story and whether or not their information is allowed to propagate out into society is another matter.
Second issue: The only ideal communist society is one where everyone is dead - because that's the only way you can get everyone to be equal.
Source: Every Communist dictatorship that murdered millions upon millions of their own people.
Source: Every attempt at a commune, setup by die-hard communists failing, miserably.
What you'll get is a massive black market for your water tokens (which are your currency) and all sorts of corruption.
Right - now I've disagreed with your premise time for a **Frame Challenge!**
You've got magic in your world. Here's how I'd do it. Have the time in hell one big struggle for survival and that the only way to survive is through mutual co-operation, then when a Prisoner has learned enough skills and learned the lesson that *helping others, in order to get what you want is the right way to live* - they are free to go out on parole - but in order to keep up the Facade of Hell (and to avoid people trying to glitch the system) - they have a false memory of Hell implanted where they *believe* that it was this nightmarish place, whilst they retain the learned knowledge of how to work with others.
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**Frame challenge: hire non-native guards and use the Hell's culture as a leverage instead of hiding it**.
Imagine how the prisoners would feel knowing about the undying loyalty of almost all of Hell's population to their people and leadership. There would be no chance for relief by bribing someone, no mercy from the menacing guards with those animalistic horns on their heads. However if there would also be some non-native and "normal looking" guards, they might soon become the prisoner's only hope, and given the horrid conditions of the prison that you described I would say it's just a matter of time.
Spreading rumors that help this would also be easier, since they would be inherently based in reality.
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The system clearly depends on the strict culture that developed over the generations of living in a literal hell. The idea of rationed food and controlled distribution of workers to minimise unemployment don't seem like things most people would be happy about, especially since this micromanagement would make the regime totalitarian by default, even if done competently and with good intentions.
Not saying this regime is pure evil, but it isn't really good either. I think that in this case, the general idea of bad outside reputation with their own point of view showing something else (which you're propably after) is still there, but mostly because of the vast cultural differences and different points of view instead of deception hiding their pure hearts.
It is a bit different from what you actually asked about, but I hope the answer helps.
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I decided to describe the evolution of scientifically plausible alien creatures and thought about how alien neurons can transmit signals to each other and is it possible in theory some mechanism that could increase the speed of thinking of my aliens (so that they think faster than us)?
Between neurons, the signal is transmitted in special structures called synapses. The transmission of information in synapses is due to the release of chemicals, that is, according to the chemical principle. While the information remains inside the nerve cell, the transmission is carried out electrically due to the fact that special electrical impulses — action potentials - propagate through the membrane of nerve cells. These are short steps of electric current, they have a roughly triangular shape and run along the membrane of dendrites, along the body of the neuron axon and eventually reach synapses. Nerve cells, in order to generate an action potential, must also have such a charge of energy, and this charge is called the resting potential. It exists, it is inherent in all nerve cells and is approximately -70 mV, that is -0.07 V, and that in our case is provided by a sodium-potassium pump penetrating the entire thickness of the membrane, which constantly pumps potassium ions into the cell, simultaneously pumping sodium ions out of it; at the same time, the movement of both ions occurs against the gradients of their concentrations. When you stimulate a neuron, it starts to pass Na+ into the cell. There is also K+ in the membrane, but it will also start coming out of the cell. If a certain threshold is reached, the cell will flood with Na+ much faster than K+ can leave, positively polarizing the cell. This results in an electrical signal. Immediately after the electrical signal is given, the cell cannot send another signal — this is a refractory period. Within 1-2 ms, the cell will not fire, even if the cell still can, and for the next signal, all chemicals will be dropped in the right direction. In order to reach the trigger threshold, several stimuli are most often required. In addition, the intensity of the signal depends on the cells, not on the stimuli. Together with the modulation of stimuli, cells react differently to each other, adding depth of information.
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Use electromagnetic transmissions, like microwaves or radio. These move at literally the speed of light, and I might add that some animals are known to emit EM radiation under certain stimuli to add weight to this idea. if you apply this system to the brain, then this could potentially allow for scientifically possible telepathy between individuals of this species, but i’m getting sidetracked.
I would suggest microwaves, as animals are known to emit these on earth, rather than radio.
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## Electrical Capacitors with Bismuth based Dielectrodes
A synapse builds up an electrical charge until chemicals are released to physically cross the Synaptic Cleft. In Electronics, capacitors have a very similar function, one electrode builds up charge until there is enough potential, and then it crosses the the dielectric gap as an electrical pulse instead of a chemical one. Capacitors allow you to pulse a signal much much faster than chemical synapses; so, if an organism COULD use electrical pulses, they would.
That said, our brains are geared far more in favor of learning and survival than just thinking fast. One of the biggest drawbacks of capacitors is that they are pretty predictable. You can keep activating one over and over again expecting the same result, but I believe the synaps beat the capacitor on our world because neurotransmitters build up and deplete effecting our ability to change our course of action when "get tired" or "of longing" for the action associated with that connection.
This is where the Bismuth comes in. Bismuth is a semiconductor which allows it to function as your resistor, but it also has a very low specific heat. This means it does not take a lot of energy flowing through it to heat it up a lot. This is important because as resisters get hotter, they become more resistive; so, your Bismuth connections would slow down the signal as it absorbs heat giving it the same sort of negative feedback loop that you get out of neurotransmitters.
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Option 1: Electrical. Lots of biopolymers (e.g., melanin) are actually conductive. Neurons could grow fibers of conductive polymers along their axons and dendrites to send regular electrical (rather than electrochemical) signals. Electrostatic induction could even be harnessed to transmit signals across synapses.
Option 2: Optical. Lots of organisms have bioluminescence, and detecting light is easy; we can even genetically engineer animals in real life to allow us to selectively activate neurons by shining light on them. Using light for cell-internal transmission would be tricky, but not totally impossible, if axons act like optical fibers--and it would work just fine over the short distances across synaptic gaps, with luminescent molecules on one side and photosensitive molecules on the other.
A hybrid of electrical intracellular transmission and optical intercellular transmission would also work.
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There is a Mystery Busters team that is solving mysteries and catching criminals (like Scooby Gang from Scooby Doo). There is no magic in the setting, the solution is always mundane, a trick done with smoke and mirrors. The technology is present day tech. The budget is 1000$, you can use only what's accessible to civilians/ can be created by an amateur electrical engineer (so, yes to soldering iron, no to magical microchips and non-existing superconductors).
Anyway, the latest mystery the team is trying to solve is a certain cult leader, lets call him Mr Fraud. He claims he is a holy man, a living saint, God's confidante, with real powers that come from faith... and has fairly loyal and fanatical followers as a result.
The proof of Mr Fraud's grandiose claims? He can emulate a very specific and very ancient miracle. [The Holy Fire miracle](http://www.holyfire.org/eng/). Specifically, any candle you bring to him, he will light as if with by magic. He would say a prayer, shield the candle with his hand as if lighting a cigarette, say "Thy will be done!", blow on it and the candle will be lit after that.
Now, the rules:
1. No preparing the candles beforehand. For example, dipping the wick in potassium and mineral oil mixture so it will start burning once the oil dries out and potassium self-immolates is forbidden. Everybody can bring him a candle of their own and he should be able to light it.
2. It must not be dangerous for Mr Fraud. So the danger of self immolation or chemical burns or poisoning or electrocution should be kept at absolute minimum.
3. While he is wearing a priestly robe with pockets, if this is to be accomplished by chemical means, the chemicals must not be kept inside those pockets. It will be mighty suspicious if Mr Fraud dips his hands into his pockets every time before he does "The miracle". A chemical that can stay on one of his fingers that when mixed with the other one on the other finger induces fire is ok.3a) No smells (like oil or gasoline) or odd colors that can be seen from two meters away. So the chemical must not be radioactive green or garish purple or anything like that.
4. No false fingers and electronic pull igniters like the one [in this video](https://www.youtube.com/watch?v=93DhhX7NDAw). The trick must be done quickly and publicly. He should be able to light 10 candles in 10 minutes, without "Is that a bird? A plane? Superman?" misdirection between. False rings or small electronics hidden inside his sleeves are fine.
5. Bonus points if he is able to do it without an external assistance (a guy with invisible UV or high voltage IR laser for example)
6. Bonus points if Mr Fraud can do it outside or in the rain.
I had the idea of using UV laser inside his "church" with the beam that lights up only on specific place and only when Mr Fraud "presses the button" on his ring. That would be one way to do it but very dangerous, one look at the wrong place and his vision is gone.
Is it even possible with today's technology? Is it possible to make it portable?
[Answer]
## Eye-tracking + computer-controlled lasers
Mr Fraud wears dark-ish eye glasses. The glasses are connected to a lanyard draped around his neck.
The glasses conceal a compact eye-tracking system. Systems like this have existed for a while; I've encountered them in nice digital cameras. The bridge of his glasses conceals a small IR receiver, like some modern VR headsets have.
The lanyard conceals a thin cable that connects the glasses to an electronic device on his belt. The device provides power and contains a transmitter.
The device communicates with a computerized system hidden in his house of worship. The system includes IR transmitters hidden at known locations around the room, plus several lasers mounted in the rafters.
The computer uses the IR information to calculate the precise location and orientation of his glasses. The eye-tracking gives the precise ignition point relative to his eyes (he must stare directly at the wick). That information is combined to give the precise location of the candle wick in three-dimensional space.
The lasers mounted in the rafters are aimed at the wick. There are several lasers up there, so that at least 2 lasers always have line-of-sight on the wick. When Mr Fraud gives the signal, the computer activates the two best-positioned lasers, lighting the wick.
Mr Fraud can give the signal any number of ways. Perhaps he wears a religious icon around his neck that conceals a button or a microphone. Maybe the computer fires at *anything* he stares directly at for more than 5 seconds.
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**The Setting**
World consists of humans with primitive technology living within an asteroid space station built by their technologically advanced ancestors. A lot of knowledge has been lost, obviously.
The station has the interior square footage of Manhattan and is home to 300,000 humans. After generations of pilfering the station for materials, the station is mostly bare of technology, little more than a complex of ultra-durable habitats on the side of a rock with a bunch of iron age maniacs living inside. The space station consists mostly of large sun-lit greenhouse areas, originally parks but now used for cultivating food. If there was ever a source of artificial gravity, it no longer works, though thankfully these humans are genetically fortified against the delirious effects of microgravity.
Over time these humans have learned manage their air quality by managing the growth and decomposition of plants, avoiding combustion, and wicking away humidity with ceramic dew collectors\*. The sun exposure of this rock can be adjusted post-hoc for whatever would make this scenario most plausible, but you can assume the base is built on Earth's moon as a default. The humans have access to the asteroid's rocky interior, where they might be mining ice (water, nitrogen, ammonia, etc.), tholin (space tar), metals, or whatever else might be useful in answering the question.
Re: plausibility comments. The station is built of futuristic "handwavium" as someone put it, so don't worry about that. These iron age humans started as a very small population in a massive greenhouse structure - managing their air quality would not be an issue until population increased. They would have time to adjust and learn as their situation became more difficult. Humans have learned how to thrive in some extremely hostile environments here on earth, living on ice sheets, deserts with single digit inches of rain per year, on floating rafts, and many other perilous places that require highly specialized survival skills. I have confidence that humans could learn to learn to live in what is essentially an enormous garden. I just need to figure out what that garden would have to look like to give them the best chance.
**Question Setup**
The air quality issue I've had the most difficulty understanding is temperature. My current understanding is that there is no need to actively heat a space station occupied by humans, because their body heat is sufficient. On the contrary, temperature control on a space station seems to be entirely about removing heat. On the ISS this is done by pumping liquid ammonia between the inside of the station and the exterior to radiate out heat.
**Question**
*How can my iron age human occupants manage the temperature of the station?* An active solution, like bicycle-powered pumps feeding through the station's legacy radiators, is not preferred. Would it be possible for the station's original design to include a passive temperature regulation system in case of power failure? For example, could the station's air be channeled through long, finned tunnels of aluminum that created enough surface area with the (near) vacuum of space to cool the air? Perhaps the number of tunnels the air flows through is manually controlled to keep the air at the right temperature. And then what would create the airflow? If the uninsulated tunnels were colder than the rest of the station, could that create a natural passive airflow?
**Bonus**
In addition to answering my question, I would appreciate references for further reading on this subject. More in-depth than the articles that come up on google. I don't really remember much physics, but I'm eager to learn if someone can tell me what area I should start looking at first.
\*Note that the station does not need to be as dry as 21st century spacestations, because there are no longer any electronics.
[Answer]
**Albedo control**
One important concept here is that the overall station temperature is relatively unaffected by how the incoming solar radiation is used. Provided albedo remains constant and no material energy sources (eg fuel) enter or leave, the overall temperature of the station will remain the same whichever of the following is occurring inside:
* There are no lifeforms or machines, it is a lifeless, inert rock
* There are machines using solar cells to do manufacturing
* There are plants growing and decomposing/being eaten without higher animals present
* There are plants being grown by humans who are eating some of them and burning others to cook food
Unless pre-existing fuel stocks (chemical, radioactive or whatever) are used to increase the temperature, this space station has a relatively simple energy model:
* Energy in = solar radiation absorbed by station
* Energy out = radiation to space
* (Energy in) - (Energy out) = increase (if positive) in temperature
Assume that the station was designed such that Energy in = Energy out as closely as possible and only fine tuning is required. With the technology available to the inhabitants, it would be very difficult to increase the amount of heat energy *directly* radiated to space. However, given some effort it would be possible to change the albedo of a portion of the "windowed" area to control how much of the sun's energy is absorbed (adding to the total heat budget of the station) or reflected back into space (not adding to the total heat budget).
Note that this strategy requires the "windowed" area to cover a quite wide arc of the station's surface or for the albedo-changing surfaces (see below) to be right up against the window, since this strategy relies on reflecting sunlight back through the window into space. Any sunlight reflected onto an interior wall of the space station becomes part of the "energy in".
Options to change albedo:
1. Have many big slabs of metal mounted on pivots, with one side as reflective as possible (painted white at a minimum) and the other side painted black. To increase temperature, pivot to have more slabs with the black sides towards the window. To decrease temperature, pivot to have more slabs with the reflective / white side towards the window. This will allow for quick, highly responsive changes in albedo provided there are enough people available to pivot the slabs - which should be relatively easy to move in microgravity - but it has the disadvantage of reducing the space in which plants can be grown.
2. Plant zones of high albedo plants. This requires a bit of botanical techno-magic from the ancestors of the current inhabitants, since the most successful plants are the ones that can absorb the most energy rather than reflect it. These plants would have been genetically engineered to be reflective and have some mechanism to discourage other plants from competing with them, yet one that does not permanently prevent the areas being used for growing other plants if the temperature needs to be increased. This method would be much slower to change albedo and consequently lower temperature but requires less human effort.
Two final notes:
* There have been several efforts to build sealed, self-sustaining habitats on Earth. None have succeeded yet, even with today's technology to monitor and active efforts to balance environmental factors. Especially with the low technology available, the space station's habitable area will need to be *huge* in order to have any chance of becoming a self-contained ecosystem.
* Unless the windows of the space station are made of handwavium, over time they will be degraded by micrometeor impacts - basically sandblasting in slow motion. Long before the windows are breached they will become less transparent. The direct temperature change will depend on whether this increases or decreases the station's albedo, but the key issue for the inhabitants is that the amount of *usable* sunlight getting through the windows to grow plants will decrease. So the inhabitants need to regain the technology to conduct major EVA's in order to fix the windows before this gets too bad. Hint: If you want a long period of primitive technology, don't put the station somewhere like a L4 or L5 point where junk and dust tend to accumulate and the windows will degrade faster.
[Answer]
**Giant Space Fans**
Heat exchange is partially a function of surface area. That's why heat sinks and radiators have so much surface area - the larger the surface, the more space there is for heat exchange. If you give the station a way to deploy giant space fans with a very large surface area, that will give the station a heat sink to dump the heat into space. (As long as the heat sink isn't under direct sunlight, because if it is, then it'll superheat.)
The most inefficient part of this process will be transferring heat *to* the heat sinks, but if you use very conductive metal frames to extend to the heat sinks, it will help channel the heat. In addition, the fans can be retracted to stop dumping heat into space if you need to retain heat.
[Answer]
**Water heating and cooling**
This method involves using the asteroid's ice supply to create cooling liquid, water is the best material for absorbing heat energy, so a series of small streams flowing throughout the space station should take away all the heat energy, as well as redistributing the energy to colder areas. The water would end up flowing into a giant tank that is only seperated from space by a thin sheet of metal, the metal would conduct the heat energy into space, cooling the water and allowing it to repeat the cycle. This has actually been attempted before in the Spanish palace Alhumbra, more information here: <https://omrania.com/inspiration/water-management-why-the-alhambra-palace-was-ahead-of-its-time/>
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**NOTE:** There's a comment from the OP stating that there's no artificial gravity. You can ignore my answer — everybody's dead. I have a hard time believing an iron-age technology could grow food (much less solve technical problems) without gravity. Unless the station's fuselage is riddled with rings they can tie ropes to, there's nothing to keep them in place to work anywhere (it's all floating). But, just in case the OP recants...
Also, I'm working on the (obviously false) assumption that the vast majority of the station is open-space covered by a dome. They'll need every square inch to have the food and oxygen they'll need to survive. If, instead, the station is a rat's maze of corridors and rooms then they'll run out of food. Farming requires space — or better than an iron-age technology.
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**You're not quite right**
The ISS does use liquid ammonia to wick away heat - but it's not just heat from the occupants. It's heat from the equipment, heat from the sun, heat from all kinds of things. And it's not helped by a design that better insulates than other craft historically.
Like the Apollo series craft, which had to have heaters.
That's good news for you, because you get to decide what kind of problem to solve. It's absolutely true that your station would have had environmental controls and it's not beyond reason that something that large and complex may have had both heaters and heat-removal systems for the same reasons buildings today have both heating and cooling systems.
*And for the record, I like that complexity. Your iron-agers might not just need to vent heat, they might need to care later when something changes, like the station's orbit taking it further from a star, when suddenly they need every joule of heat they can get.*
**But let's focus on heat removal**
When push comes to shove, all space-based systems rely on one passive component: large vanes not at all dissimilar to the heat sinks you'll find in any large computer system to radiate heat into the void. All kinds of active systems may improve the efficiency of moving the heat from the inside to the skin, but eventually you need to move the heat from the skin to the void... and that means having something to move the heat to.
That's an important issue depending on how "realistic" you're trying to be. Space isn't empty — but it's darn close — and heat isn't an object (like a photon or a particle of mass), it's actually a characteristic of an object. When you say you want to get rid of heat, that means you're trying to move energy from one object to another.
And you have to have another object to move it to.
**To be fair, this might not be a problem you want your iron-agers to deal with**
To consider a tangent for a moment, I'm not convinced that an area the size of Manhattan could absorb enough CO2 and generate enough oxygen to accommodate 300,000 people. If we ignore the value of Earth's ocean in this regard, Earth has only about 12 million square miles of arable land (land that can be used efficiently for re-oxygenation). 12e6/8e9 = 0.0015 square miles for each individual or 450 square miles and Manhattan is only about 23 square miles. No matter what the "we have too much population!" people want you to believe, the Earth can cater to a much larger population than we have today, which would reduce that ratio. But if we assume Earth's at its practical limit, your population needs almost 300% more land if plants alone are used to solve the problem.
But it's more likely that the space station has a very active ventilation system that scrubs CO2 and re-oxygenates. You need that before you need heat removal and from an engineering point of view, it's more likely they're integrated than not. Which means if heat removal goes down, the ability to breathe went first.
*But that's boring, let's ignore it.*
**What can we do?**
Iron-agers. The iron age ended around 550 B.C. (or 800 A.D. with the Vikings, it depends on who we use as the reference), so the tech is sometime before that. They can manipulate metal, which means they can work with parts they have. They could figure out bolts, but they couldn't figure out modern welding and they couldn't figure out modern alloys. They certainly couldn't figure out things like carbon fibers and couldn't understand aluminum, which wasn't discovered until 1825. No knowledge of electricity... precious little knowledge of hydraulics and pneumatics....
*I'll be honest with you. At this point in my answer I'm more than tempted to switch this to a Frame Challenge that claims it's impossible for you to have iron-agers on a failing space station that survive. I'll try to trudge on, but finding a solution that an iron-ager could deal with....*
* Open a window. A tiny window. An iron-ager would think in terms of *letting the heat out,* not in terms of *exchanging the heat.* They'd die, probably quickly, but it's the first option. Punch a hole in the station. They'd have the tech to do that (maybe, but it's suspension-of-belief-able.)
* Make it rain. Assuming the station has multiple ways or some redundancy to remove excess heat, another solution is to pump water to the ceiling and spray it around, causing rain, causing a drop in temperature. This has the effect of pulling the heat to the floor of the station, where hopefully there's some tech to move it further away.
* Plant more plants. Very simplistically, plants are endothermic. They consume energy to grow and thrive. If we ignore the details of reality and strive for suspension-of-disbelief, then the more plants there are, the cooler things are because they're absorbing the heat.
* Let the smoke out! If the station's cooling system still exists (even if it's not operable), our intrepid iron-agers may find a pipe or two that are cold to the touch, and in a manner similar to opening a window, think that the solution to the heat is to let the cold out of the pipes. Yeah, liquid ammonia, dead iron-agers... but they don't know that, and it would look like smoke as the fluid violently evaporated from the pipes.
* Push more air through the ventilation system. Assuming that the heat exchange system is still (at least basically) working, then moving more air through the vents could (believably!) dump more heat. This means using hydraulics to drive gears that spin fans.
*And that's all I have*
An iron-age society would not be capable of fixing anything remotely complicated in terms of a space station. That's a pretty ruthless limitation. Personally, I'd avoid anything other than the most simple systems going down. Focus instead on things that don't depend on knowledge they don't have to resolve (like the replicators failing. Easy fix. Cannibalism.) or external problems that they can address with their tech like a small hole from a micro-meteor (pound a nail into it! Fold some oily cloth over the nail first!). Half the fun would be walking through the trial-and-error-before-they-die solution process.
**OK, a bit of a Frame Challenge**
Finally, remember one thing about your iron-age condition: it's actually really, really, really, really, really hard to lose knowledge. The station would have libraries (digital or otherwise), technical manuals, even class rooms for children, given its size. People would have all kinds of knowledge that would be more likely to be passed on than forgotten. The more specialized the knowledge, the more likely it would be lost. But iron-age level? It's more likely they'd regress back to the late 1800s and stop. There's certainly nothing stopping you, the worldbuilder, from simply declaring it to be so... but beware trying to explain it. It's a lot harder to explain realistically than you might think.
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In my story the cobblestone roads have each individual stone actually be alive, and during the day time they remain completely still. The stones (during the nighttime) almost kinda swim in between each other (below the stones lies a mucus, cement-like paste they make during their life), with the closest stone taking its place it left behind. Cobblestones tend to have two little simple eyes which can really only sense light. The cobblestones simply clone themselves to make more, and they eat by simply absorbing nutrients through their skin. When they are cracked, they either die or become hyper aggressive and even move during the daytime. I was thinking of what animals the stones would be related to, maybe siphonophores, overall this living-stone idea could definitely be improved upon with others ideas and knowledge with biology.
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Thought provoking. Questions that you might want to answer: what is the protective strategy that the animal uses to adapt to the environment that the cobblestones are providing? How is it related to food gathering, a procreation cycle or evading predators?
There are a lot of ways that an animal could build a surface as protection.
model a: Protective sleeve- The cobblestones are manipulated by the animal . Giant silk spinning caddisflies? Apparently there is a form of fly called a caddisfly (Trichoptera)that builds a protective case for itself out of stones in the larvae phase. There is an artist that uses these flies by giving them precious materials to craft jewelry. Obviously they are small, have limited lifespans, and further would require assistance to consistently move in the direction of a road, such as paving it first with dead leaves, Algae, and detritus which they eat.
model b: burrower with a shell- In this example the cobblestones don't make the protective sleeve, the shells of the animal look like the cobblestones and they are using it as a form of camouflage like a kind of sand crab or turtle.
model c: The cobblestones are more like little nests. Multiple creatures are putting together a bunch of little homes that over time accrete to have a durable surface. Animal architects like this include many species.
Since this is fiction you would adapt one of these strategies to your invented animal.
Then you get into another intriguing side of this question, which is how do humans engineer the road properly, in terms of toughness, durability, shape and causing the animal to live there.
[Answer]
# Start with ticks.
The ocean has offered us many beautiful, tempting templates to begin with: barnacles, chitons, corals and so on. The *problem* is that these typically build their skeletons from simple minerals - calcium carbonate or silica, usually. These are sea creatures for good reason: because the minerals can be found in the sea, but don't come down in rain. Your cobblestones can't wander the countryside, and they need to be viable on roads crossing many different types of geography, so they need to be able to produce a strong skeleton without needing extra elements.
For this reason I would suggest starting with a [tick](https://en.wikipedia.org/wiki/Tick). It isn't easy to crush a tick with your fingers (also probably inadvisable). They are evolved to survive a *long* time without food or water. What we need to do now is:
* Break their blood habit. Ticks have a mechanism to absorb water even from the air - we'll make them eat water. To survive, we'll give them photosynthetic organelles or symbiotes in their integument, and supplement this with a [published method of photosynthesis](http://news.bbc.co.uk/earth/hi/earth_news/newsid_9254000/9254445.stm) said to be used by hornets. Note that this means the adult stage no longer needs to be able to expand its abdomen, so we can do internal reinforcement.
* Engineer the tick to withstand more crushing pressure. Typically, an unfed tick is much harder to crush than one that is engorged. But here, our engorged tick will develop many reinforcing partitions internally, which make it act like a large number of tough small ticks.
* Harden the integument. Everyone wants graphene for everything nowadays, but it seems hard to get, and I worry it may be overused in writing. Practically speaking, a road paved in teeth ought to last for a while, so maybe just transfer vertebrate enamelogenesis to the ticks to put miniature protecting teeth in their exoskeletons at the places with the most internal reinforcement.
* Scale up. Ticks are small, and there's a limit how far we're going to believe they grow. But they die, and leave these enhanced durable skeletons that are slowly ground to powder. So we'll suppose the existing ticks, foraging for trace nutrients, ever so slowly cement together the powdered or partially intact skeletons of the dead ticks and fill them in with a solid secretion. They work together to turn these round and round, creating large balls (cobblestones). The ticks have custom-made burrows reserved in these balls they create, so that each ball has multiple little tick legs and heads that can project out from it in every direction. They can work together to roll it around to a good spot if there is room to work with. The young, homeless ticks wander slowly in the spaces in this network, looking for their place.
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Right, lets try this again.
I'm making a planet for a book I'm writing. I want to know if the planet I outline here is scientifically probable, able to support life, and what the climate would feasibly be like, compared to Earth.
First off, the planet is a terrestrial world, about 1.1 Earth masses and 1.04 Earth radii, giving it a surface gravity of 1.144, comparable to Neptune. It orbits a K-Type star, at a distance of 1.2 AU. It has an Albedo of 0.088, lending to a rich ash colored geology. It's axial tilt is 12 degrees, and its orbited by a moon around 0.0268 Earth masses, and a radius of 0.22 Earth radii. Said moon's Bond Albedo is about 0.20. Overall, I'm going for something along the lines of a mini Arakis in terms of look for the moon. Its orbit is 384,400 km from the planet.
Now, things get complicated with this last feature - a silicate debris ring, about the mass of Ceres (0.00016 Earth masses). It's inner edge being 2.56 Earth Radii from the surface, and 3.48 Earth Radii at its outer edge, making it 0.92 Earth Radii long. Since I'm bad at math, lets say its about 9.5 km thick. Their Bond Albedo is about 0.03.
I also have some more specific questions, along with my general ones above:
* Would black body radiation from the ash-colored deserts lead to the planet becoming warmer than Earth, or would dust being kicked up in the upper atmosphere make it cooler? Or would the two factors cancel each-other out?
* Would the rings cause an annual oscillation between antarctic temperatures and tropical temperatures where their shadow is cast upon the planet? Would this lead to massive storm-fronts and a general lack of plant-life around the tropics?
* Apart from more mild seasons, how would a 12 degree axial tilt affect climate on the planet's surface?
* Do I have to reduce the size of the moon to allow the rings to exist along geologic time-scales?
* If plant-life can exist on the planet, what color would they be to maximize energy absorption from a K-Type star?
Please also let me know if any other glaring problems become obvious from what I've outlined here. I want this to be as scientifically accurate as possible, so I can have a better idea of what needs to change and what's working well. Thank you in advance for your help!
Additional Info:
Sun Characteristics): The Sun is a K-Type Star, with a Luminosity of 0.79 L and a temperature of 5518 K. According to the calculator Sonvar provided (thanks, by the way!), its Inner Habitable Zone is 0.845 AU, and Outer Habitable Zone is 1.49 AU. It's Stellar Flux on the inside of the HZ is 1.107, and on the outside is 0.356.
Water on the planet): Ideally, I was hoping the planet would have comparable amounts of water to Earth, maybe about 72%? If it means anything, I was thinking it'd have two main continents: one in the northern hemisphere, about the size of Eurasia, and one near the equator, about the size of Central America. It'd have a chain of islands comparable to South-East Asia in size off of the latter continent.
[Answer]
OK, let's talk about the planet's estimated temperature.
The estimated temperature takes into account star luminosity, bound albedo and distance from star.
The estimated temperature given by this calculation was - 39°C. By comparison Mars estimated temperature is -63°C and Earth -18°C. This is known as the equilibrium temperature where theoretically the planet is warmed only by it's star. This means at this temperature the energy emitted balances the energy received. Of course, this is not the actual temperature, as Earth is considerably warmer, due to the greenhouse effect and other factors but even with a similar greenhouse effect your planet would still have an average surface temperature of -39°C.
<https://www.astro.indiana.edu/ala/PlanetTemp/index.html>
I still think your planet would be very cold even with the ameliorating effects of low albedo.
[Answer]
For plant life around a reddish star, your plants could have evolved upshifting organelles around their chloroplasts that upconvert the reddish incoming light into a frequency range useful for chlorophyll or an analog to work.
I think the debris ring, 434 million cubic kilometers of materials spread as described across about 216 million square kilometers, won’t be making much difference to the light on the surface. But let’s check. If the ring is less than 2 kilometers wide, and the volume of material is evenly spread, then that volume of material is nearly solid. Not sure how stable that is. It would shade part of the planet.
There are a lot of tools available to warm up your world — You can bring it a little closer, put any of countless heat-trapping gasses (<https://physics.stackexchange.com/questions/101017/how-do-greenhouse-gases-trap-heat>) in your upper atmosphere, have the ground trap heat, internally generated heat from deep fissionables, or still coasting on leftover heat from planetary formation (or whatever put that debris ring in the sky).
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Aerosolians or 'loopies' live on hypersonic trains. They stick to the sheetmetal and collected microbes from aerosols captured by tiny pockets in their skin. Because of the high speed they can collect enough energy through only bacteria, yeasts and protozans.
They are about the size of an adult beaver. They hardly ever move and the trains are moving at about 7000km/h for 8 hours a day.
**How much do they eat?**
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Since blue whales are very large ann only eat Krill I think that your creatures could eat relatively small amount of bacteria( and bacteria are abundant) to live.
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From your description of the creatures it looks like their method of consumption is passive. Since you said they hardly ever move implies they can move if they wished. So they are a higher on the evolutionary tree than sea sponges. A sloth consumes around 110 calories /day. About as much as a big apple.
or:
1 Cup of Blueberries
1 Hard-Boiled Egg.
1 Orange.
1 Cup of Strawberries
1 Piece of String Cheese
8 Baby Carrots
1 Cup of Cheerios
1 to 2 Cups of Fresh Melon .
Not knowing how they deal with their environment. Assume it can get cold and hot, changing air pressures that's about as close as I can imagine to get.
[Answer]
We need a creature that subsists on microscopic organisms, with an aerodynamic shape, and a land dweller. **I propose a slime mold.**
[](https://i.stack.imgur.com/iX4GN.jpg)
<https://www.sciencealert.com/this-creeping-slime-is-changing-how-we-think-about-intelligence>
These macroscopic amoeboid sheets adopt aerodynamic shapes by flowing according to forces produced by air currents. Shapes of each organism on the train will differ according to the topography of the train and local air flow. Problems solving of this type is within the power of slime molds; see link.
As depicted in the drawing in the OP, these creatures tend to have a rear portion lifted above the level of the train. The consequent low pressure under the organisms entrains dust and microbes that are its food.
Inorganic particles and waste are pushed thru the plasmodium body to the top, where it accumulates and serves as a sort of carapace to protect from UV light and also minimize water losses. Unfortunately that makes these organisms look like patches of dirt on the train.
I was worried that living on the train would dessicate these organisms. But it turns out the trains are so fast that the high speed / low pressure air produces a vapor trail or "bullet trace" like that of an actual bullet. The lower pressure air by the trais has less ability to hold moisture which precipitates out in droplets. It is always humid right next to the train.
But as regards the OP and "how much they eat" - it depends! The aerosoleans come in very different sizes. Occasionally a big one will occupy the whole top of the train, side to side. Metabolic rates will vary with temperature. And "eat" - does that mean caloric intake, intake by volume or intake by mass? The aerosoleans wind up taking in a lot of dust that they cannot use as food.
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I am sad to say I could not find any real life examples of any of the polyphyletic group called "slime molds" actually using a carapace to protect against dessication, so I made that up. As regards bullet trains leaving a vapor trace the physics is sound but I could not find images of a bullet train leaving such a trail.
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I've always liked the idea of merfolk having extra fins(by this I mean fins like the dorsal and pectoral ones and not the main tail fins). After seeing [this](https://biologyeducare.com/fish-fins-its-types-and-functions/) article about how fish use their many types of fins it only interested me more. To me it seemed like they would help merfolk swim more efficiently, but after coming across [this article](https://worldbuilding.stackexchange.com/questions/94586/why-merfolk-do-not-evolve-dorsal-fin) on dorsal fins, I began to question how useful they would be to merfolk. In the article they mentioned that their hands would serve the same purpose as the fins would while in the water, but both the question and answers did not give much information to go by. The merfolk in my world will mostly be the typical half-fish-half human type as of now but some different types will have variation in their anatomy. If some types of fins could be useful, then what types would be useful and which ones would not? It would be amazing for the merfolk in my world could have these fins, but I don't want them to do more harm than good.
I hope this question makes sense. Please let me know if I left anything out that should be considered. Thanks!
[Answer]
**Your merfolk do not use hands to swim.**
Let us consider the Man from Atlantis. The 1977 TV one starring Patrick Duffy, who went on to have some fame as Scuzzlebutt's leg.
[](https://i.stack.imgur.com/YKI5l.jpg)
<https://www.youtube.com/watch?v=4EI6jDeRtAs>
He swims using his back and legs in a butterfly kick. His hands stay at his sides, sculling. He never reaches forward. [Here is a good gif of him swimming.](https://makeagif.com/gif/man-from-atlantis-swimming-hRfCfq?origin=category&source=tv-gifs&order=new&page=3&position=1) This method of swimming makes a lot of sense for the mammal body plan and is what cetaceans use. Patrick Duffy fairly cooked along underwater with this stroke. I cannot say this was a great show but he was a great merman.
Fins to provide stability would help Patrick, I think, possibly at the expense of his considerable aesthetics. A dorsal fin at least but one could justify additional fins as your own aesthetics deem appropriate.
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## Fins just need to be seen as *sexy*
There are many reasons for evolutionary features to evolve other than pragmatic ones.
For instance something could evolve because it is *sexy*. As your merfolk culture is half human, one could expect a similar emphasis when choosing a partner to be on traits that are sexually desirable, perhaps there is great respect for other fish, they appear as strong swimmers, and are thus sexier, so eventually dorsal fins would appear in response to this desire.
This is why we have colourful fish, 'flowery' fish with lots of visual spectacle. It is actually damaging in terms of practicality and pragmatism, but useful for signalling to mates your prowess.
And in many ways, *the impression* of your prowess is more important than *actual prowess*. This is [called signal theory](https://en.wikipedia.org/wiki/Signalling_theory), so for instance in our culture being 'strong' isn't necessary about actual strength, but just that we 'look' strong. So this is reinforced by cultural or psychological attitudes more than physical requirements.
This theory explains:
* Why birds have so much plumage, even if it severely hampers their movement, such as peacocks
* Why plants are willing to sacrifice themselves to create good looking flowers, in order to appeal to insects
[Answer]
Each fin needs different considerations
# Pectoral Fins
Pectoral fins have the major disadvantage of being impossible with normal anatomy. There are some solutions if you're willing to break from the vertebrates:
* Humanoid shoulders with low fins. This would require few alterations; all that should be required would be for the arm-pectoral muscles to be split from eachother to provide space for the fins, which would therefore need to use less space. One way to achieve this could be achieved by splitting the sternum into two widely spaced bones, with some internal bone-scales for protection
* Reptilian arms with high fins. This should be easier to explain, at the cost of being less humanoid. This would require only that the arm-raising muscles don't go all the way to the fins, and vice-versa
* One shoulder. You could also have a single pair of humanoid (or reptilian, for that matter) shoulders, which would have both the fins and the arms. This would mean that the fins and upper-arms would be linked together in motion (though you might be able to explain a little bit of independance with extra shoulder muscles)
Even so, pectoral fins wouldn't have much utility alongside arms. It is entirely plausible to just leave them out
# Dorsal Fins
Dorsal fins are useful for stabilization, and easy to add. There aren't many disadvantages for a mermaid
# Adipose Fin
The adipose fin is a small fleshy fin behind the dorsal fin, which has some sensory function. There isn't any reason to add it or leave it out
# Pelvic Fins
The utility of pelvic fins seems to depend on how your mermaids swim: If their tail moves sideways like in fish, then they would be quite useful for stabilization. However, if their tail moves up and down like marine mammals, they most likely won't benefit (and may even be detrimented) from pelvic fins
# Anal Fins
Anal fins would aid in stability, like the dorsal fin. However, due to their positions, it's likely that these fins could interfere with reproduction, depending on how it happens. They should only have anal fins if they use external fertilisation like in fish
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[Question]
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I want to create a two alternative monarchy system. I would like someone to help me improve upon that idea. The two monarchy system I would like to create is called democratic monarchy and non-bloodline monarchy.
The democratic monarchy is that a king can't have the crown price become king. It's that king's nephews and his children are elected by the citizen of the kingdom. So, the princes fight for approval from citizens. They can get approval from the citizens by helping the kingdom from various ways.
The non bloodline monarchy is that the king can't have his own kids to take the mantle. Instead the king adopts various talented children around the world and train them to see who would become the king and take the monarchies name to their own.
The problem I'm facing is that corruption in the democratic system. Where the king wouldn't let his nephews become the king or not letting the general population vote for their best interest. The princes and other killing each other etc.
The other problem of non-bloodline system I'm facing is that what would be the appropriate age to adopt the children around the world? And what would be the best way to see who's talented and a way for it not become bloodline based monarchy?
[Answer]
## Arranged Marriage:
If you think the Charles & Di story was tragic, look at the marriages royals through history have endured. Royal marriages are almost never about love & attraction, or even compatibility. They are about power and talent.
To make a system where talent & ability can be joined to a royal system, allow the wives and husbands of royals to rule. Inheritance of titles is still through blood, but a parliament is responsible for selecting who the members of the royal family can marry. This can be by vote, or amongst a pool of candidates selected by a medical and intellectual evaluation (to weed out those with known family or mental/psychological problems). The potential future ruler can then be selected, married off to a son/daughter/cousin of the king/queen, and the current ruler may or may not have input into the process. Anyone found unworthy has their marriage annulled or is divorced. Free will really doesn't come into the equation.
You might want to use the term 'king' or 'queen' for the royal family member, and 'ruling consort' or something similar for whoever is making the actual decision-making.
A potential candidate may even be married before their candidacy, but their original marriages are either dissolved or polygamy is allowed and the marriage to the royal is considered the primary marriage.
This way, you maintain the royal bloodline, but at the same time the actual ruler is typically someone outside the royal family (unless an extraordinary royal is selected). If the king or queen (son/daughter of the previous ruler) is really talented, they could still be picked as the ruler over their consort.
This even allows the royal family to survive conquest and defeat in war - the conquerors simply marry into the family and become the new royal spouses. The true power is almost never handed to the children of the ruler, but passed to the most worthy candidate.
This somewhat sidesteps the corruption issue, since you still need a nominating system to pick who the ruler will be. If that system is corrupt, then the selection of the ruler will be corrupted. But there is no way even today to eliminate corruption from the ruler selection system.
[Answer]
Nepotism or non-hereditary dictatorship?
I'm a bit confused as to what exactly you mean by a "two monarchy system"; are you trying to decide between two alternative systems (i.e. an elective monarchy where the incumbent ruler's children can't succeed, and a designative monarchy where the ruler adopts a bunch of children and picks the best one to be heir) or proposing a system that combines all these elements?
Assuming it's the former, I will say that historical precedent suggests both your systems will have corruption issues. Elective monarchies are actually very common historically (check out the Holy Roman Empire, Poland-Lithuania, Bohemia, Jerusalem, most Scandinavian kingdoms, etc) but the example which fits your system best is the Papal States; here the ruler is elected and his children cannot succeed him because, as a priest, he cannot have legitimate heirs. Many popes did therefore promote a number of their nephews and other relatives as potential successors, notably the Borgias; for instance, the uncle of Alexander VI (better known as Rodrigo Borgia) was Pope Callixtus III. Unfortunately, the Borgias' lurid reputation for scandal and the fact that such practices literally gave us the word 'nepotism' (original Latin meaning: nephew-ism) may give you a clue that this system did not exactly eliminate corruption. If anything, the need to find important jobs for a whole family network of potential heirs encourages rampant cronyism and patronage-politics even more than straightforward father-son succession does.
As for an adoptive monarchy, as others have noted the Roman Empire did practice this for a while quite successfully, but it broke down when emperors gave in to the temptation to pick their own sons instead. Arguably, many modern dictatorships also function this way, in that a ruler-for-life raises up a number of protegées and eventually designates one as the next supreme leader. I would suggest that there's not much point adopting potential heirs before adulthood, when you can pick those who are already proven politicians. Fitness for the complex, highly context-dependent task of national leadership is not like being good at maths or music; it's not a skill you can reliably identify among a whole country's worth of precocious children.
Finally, I'd conjecture that both your ideas seem to rely on the hope that a degree of healthy competition among potential heirs will produce the best outcome, but I don't think that's how these things usually go. In a monarchical society that is at least partly aristocratic, this competition will inevitably be waged largely through backdoor campaigns for favour and influence i.e. the very means most susceptible to corruption. The main advantage of non-hereditary monarchies is actually that they can avoid the problem of being stuck with an heir who is obviously unsuitable, such as a madman, a child, or (in a very patriarchal society) a woman. On the other hand, the main downside is that having a bunch of potential heirs in the running until the last minute is that - unless you have a very stable, strong state - the losing candidates become natural foci for dissent as anti-popes, pretenders to the throne, Ottoman-style fratricides, etc. So to cut a long story short, your systems have benefits if handled correctly, but also come with problems and are unlikely to significantly lessen corruption.
[Answer]
## You're looking at a mixture of the Roman Empire and Scotland.
Let's take a look at the individual elements of your suggested system.
>
> The king can't have his own kids to take the mantle.
>
>
>
Interestingly enough, the Scottish actually used to do something like this. Under the Tanistry system the king's successor was one of the royal houses' chiefs, elected by the other house chiefs, in something akin to the Catholic College of Cardinals. This was used almost continuously in Scotland for 700 years, ending when Malcolm III killed Macbeth[1].
>
> The princes fight for approval from citizens.
>
>
>
This is basically what the Romans did for their system of succession, which is why people like Vespasian were able to become Emperor without too much fuss[2].
While both these systems worked very well, it's worth noting that they both had the same problem: helping your country is a lot of work, so hopeful successors spent much of their time arranging "accidents" for possible rivals.[3]
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[1]: Yes, there was a real King Macbeth. It's worth noting that he wasn't the horrible guy Shakespeare portrayed him as; the houses had elected him Tanist (successor), so he was justified in his wrath against Duncan. He was, by all accounts, a very good king.
[2]: At least in theory.
[3]: The part of *Macbeth* immediately after King Duncan's murder does a pretty good job of showing what I'm talking about.
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[Question]
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I want a creature to be able to set itself on fire when in danger, but I need a way to protect tendons and heat sensitive organs like the brain and kidneys.
I'd imagine this creature to have a perfect insulation method evolved after millennia of heat stress caused by wild fires and eventually it evolved a mechanism to set itself on fire and exploit its own resistances. Now to burn, it needs fuel and fat tissue is the best around, so good in fact people used it for centuries to make explosives.
The immolation mechanism would be kind of like a lizard losing its own tail on purpose, but more extreme. Now there's a problem, cancers.
Cancers are not a chance, they are a certainty, if an animal regenerates fast enough and lives long enough it is implausible to not see a few cancers. When we also add smoke, we have a recipe for disaster.
Can cancers be isolated on the regenerated part? Imagine that animal having to rebuilt its skin once or twice a year... Many cancers are to be expected, but if the cancer remains isolated on the skin, then burning it off won't be a problem... If it spreads then the animal won't live much.
[Answer]
**Cancer does what Cancer does**
Even disregarding a lot of other difficulties the creature has to overcome, like losing body heat during intense activities, a body can't isolate Cancer. The prime reason why Cancer is dangerous is that it's made from the cells of the organism. This means it has all the enzymes and other flags that make the body identify, *correctly*, as it's own. That it's a dangerous mutation that will generally reroute blood vessels and such for more nutrients and in some cases grow wildly in any direction isn't noticed by the body. Some Cancer might mutate in such a way that they are cleared, but the one that are a health hazard are invariably recognised as our own body and thus not acted upon.
Isolating the skin layers and the rest of the body will not help, as some Cancer variants grow into any direction they want. Some variants can also be transported by the blood, which is an extra property of some Cancers, so an active system should be made in the blood for separation of the skin and the body, which is just wasteful. Even then it can nest close to the rest of the body and potentially grow into the precious area's.
I could go on, but in the very principle Cancer can't be isolated by the body.
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