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[Question]
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I want to explore an advanced Native American civilisation; assume their general 'technology level' is 'equivalent' to 13th-century Europe. Biggest difference is that their metallurgy is lagging behind; this country is only just starting to make use of iron for instruments larger than tuning forks, and they haven't invented any kind of steel yet. Other than that they're as advanced as you would expect: they have universities, an expansive bureaucracy, a long literary tradition, and lots and lots of warfare.
The important thing is that they got their civilisation to such heights without any contact with the Old World whatsoever. Because of this lack of cross-pollination up until the time of their discovery of the Old World, I have vested interest in making this culture 'strange' from the European perspective, including their solutions to known problems. Convergent evolution is a thing, but I do not want to rely on that to such an extent that any American tech I describe sounds like an Old World thing with a paint job.
So I want an original siege engine. Assume that, for much the same reasons as Old World states did, this civilisation too began to use stone fortifications and eventually fortresses. To deal with those, Old World engineers have developed [many](https://en.wikipedia.org/wiki/Roman_siege_engines), [many](https://en.wikipedia.org/wiki/Chinese_siege_weapons) [ways](https://en.wikipedia.org/wiki/List_of_siege_engines) to sling projectiles either against those walls at great speed, or over the walls and onto the weaker buildings inside. That's what catapults, trebuchets and ballistae are. My idea is a giant [atlatl](https://en.wikipedia.org/wiki/Spear-thrower) or spear-thrower; to be realised as effectively a combination of a catapult and a ballista.
[](https://hands.unm.edu/atlatl.gif)
Imagine this mechanism, but instead of a human arm you have the arm of a catapult.
[](https://i.stack.imgur.com/KUdeb.png)
The question: could this be a good alternative siege engine? I am considering two things:
* Would it be *suitable*: is this instrument effective as I described it?
* Would it be *sensible*: does it exist in a [local optimum](https://en.wikipedia.org/wiki/Local_optimum)? I am kinda worried that any clever engineer would naturally decide to swap out the spear projectile with a ball and thus make it a regular catapult. But I am not sure of this: a giant arrow as a projectile is easier to aim, and in real life, ballistae only fell out of use with the fall of the Roman Empire.
If necessary, maybe the inefficient metallurgy could play a role in keeping the giant atlatl a viable machine, effectively preventing it from turning into a catapult? As said my interest is in keeping this civilisation weird.
[Answer]
## Not in the way you are thinking.
People already have made "upscaled atlatls"; they're called catapults and trebuchets. They just didn't load them with javelins, for several reasons.
1. As @L.Dutch-ReinstateMonica already mentioned, **logistics for the ammunition would be an issue.** Like it or not, those javelins would have to be pre-made and then carted to wherever you want to use the atlatl. It's not a *huge* problem, but it is appreciable.
2. **They would be supremely inaccurate.** Having used atlatls before, I can tell you from experience that using them requires many small adjustments *during the swing*, as otherwise the javelin will go flying off in the wrong direction. Having also used catapults, I can also tell you that **you simply cannot get that level of fine control with a catapult.**
3. **Even if you could make it accurate, it wouldn't be effective.** The atlatl is an antipersonnel weapon. The ancient equivalent of a [hand cannon](https://tvtropes.org/pmwiki/pmwiki.php/Main/HandCannon), to be sure, but still an anti-personnel weapon. Even scaled up, it wouldn't have the impact force to deal significant damage against the ten-foot-thick walls common in that era. Medieval militaries, recognizing this, loaded their atlatls with rocks. You could conceivably use it like a ballista, but **it would be cheaper to just get a few ballistæ in the first place.**
EDIT: To clarify my third point, a javelin of the same weight as a rock is going to do more or less the same amount of damage, but it takes a much bigger catapult to fire the javelin than it does the rock.
[Answer]
## It Would be Very Hard
Atlatl's store energy in the javelin itself. The heavy stone/iron point resists motion more than the wooden shaft, since objects at rest tend to stay at rest.
This results in compression of the javelin shaft like a spring. When the Atlatl leaves the launcher, it un-compresses rapidly, pushing forward.
You can see this in the bowing of the javelin if you watch a [slow motion](https://www.youtube.com/watch?v=io-Rs_wkd7I) video of an atlatl.
Atlatl actually tend to be made of soft wood, because hardwood doesn't flex enough.
To make a very large scale atlatl would be... interesting - you'd basically strip a pine tree, attack a big rock at the front, and then push it really hard from the back.
## Maybe an H Frame could Work
Basically, we're building a giant slingshot, but we use a dart instead of a pebble, and counterweights instead of rubber bands.
Build a large scaffold shaped like a capital H. The atlatl sits with the back end on the ground, and the heavy end on the horizontal centerbar. Pulleys at centerbar height ensure that when the counterweights drop, the force on the javelin is applied at the rear, with the line of motion through the point.
We need the motion to be in line with the javelin in order to create the bending, which stores the energy from the counterweights for an explosive release.
## Problems
The atlatl isn't cheap! The length, springiness, weight, etc are all important to getting the bowing right, and after you've invested all the time and energy in finding / cutting / tuning your javelin, you only get to use it once. This is the basic reason why bows are better for warfare than atlatls.
The too little force, and the atlatl doesn't fly right. Too much force, and the pine tree explodes in the middle of your army, and then doesn't fly right.
The pulleys - It's a non-trivial engineering challenge to transfer the force from the falling counterweights to the log / tree / atlatl.
[Answer]
The main issue I see is that, while making a spear is not that resource intensive, making an upscaled spear to fit an upscaled atlatl would require much more resources, on top of those needed to build the atlatl.
Consider that carrying along all the ammunition is a burden on logistic: while a catapult can be loaded with materials found on the spot (stones, boulders, bricks), saving effort in transporting them, making a large set of upscaled spears require having decent trees around with straight and well balanced trunks, and not just any tree. That would imply taking along the ammunition.
From a pragmatic approach I think a catapult would still be preferred.
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[Question]
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I had Originally thought of using Nicoll-Dyson beams to propel probes and small ships from the Milky Way to as many galaxies as they can reach to turn stars in those galaxies into [Shkadov thrusters](https://en.wikipedia.org/wiki/Stellar_engine) to return to our galaxy.
The problem with Shkadov thrusters is they have extremely slow initial acceleration due to the mass of the star but once its around a billion years a star like our sun can have moved 35,000 light-years and will be moving at 20 km/s by then.
Nicoll-Dyson beams also have an issue of the beam spreading and being less effective propelling a ship once we get into inter-galactic distances. So I thought since they are arriving home on Shkadov thrusters they could also have left the Milky Way in the same way, at least your massive fuel source isn't millions of light-years away.
For the return journey the majority of stars will be red dwarfs due to their trillions of years life span but they are extremely slow moving stars due to their low energy output so a massive star may be the best bet as even though they are much more massive and harder to move their energy output is magnitudes higher but the major problem with these stars is their short life span.
What makes this calculation even harder is that the two galaxies are moving towards each other and it could be asked why bother traveling there when we will collide in 4 billion years but I would like to arrive in Andromeda long before the merger.
Is there a type of star that could get to Andromeda as a Shkadov thruster long before the merger or could even a Nicoll-Dyson beam using the correct star type propel a probe or small ship all the way to Andromeda in the shorter travel times I am after?
Edit: someone had done some calculations and they said it is not possible to reach Andromeda with a massive star, their calculations put our suns output as being able to reach in 20 billion years and a 10 solar mass star reaching in 1 billion years, both travel times being far longer than their life span but they did have an interesting suggestion of riding the supernova blast for the remaining journey.
[Answer]
You want to use light to push the star.
The more light the star emits, the more push it can produce. But to produce more light the star needs more mass, which will affect your acceleration. Where is the sweet spot?
According to [Wikipedia](https://en.wikipedia.org/wiki/Mass%E2%80%93luminosity_relation), the mass-luminosity relationship can be written as
${L \over L\_{S}}=p({M\over M\_s})^q$
where
* if $M<0.43M\_s$ then $q=2.3, p=0.23$
* if $ 0.43M\_s < M<2M\_s$ then $q=4, p=1$
* if $ 2M\_s < M<55M\_s$ then $q=3.5, p=1.4$
* if $M>55M\_s$ then $q=1, p=32000$
If we assume that thrust is proportional to luminosity, the above can give us the dependence between thrust and mass and thus allow us to calculate the maximum acceleration we can get, assuming that in the non relativistic regime we have $a=F/m$
We get that
$a = {p L\_s \over {M\_s}^q}M^{q-1} $
Finding the maximum vs M of the above function will give you the optimum thruster.
As a crude engineer I have plotted a chart of the acceleration vs the mass of the star, resulting in the following chart
[](https://i.stack.imgur.com/ViJLV.png)
Which tells that the best thruster is a star with 55 solar masses. Bigger than that will not give you more acceleration.
If you are interested in maximum deltaV instead that in the maximum acceleration, you have now to combine the thrust with the amount of time it can act, given by the star lifetime.
This [table](https://en.wikipedia.org/wiki/Stellar_evolution) gives an indication of a star lifetime based on its mass
[](https://i.stack.imgur.com/smklr.png)
conveniently computed into a table where $deltaV = a\cdot time$, you get the following
[](https://i.stack.imgur.com/Jf4l1.png)
It is evident that the maximum deltaV will be provided by a star with 60 solar masses: a lot of push for a very short amount of time.
[Answer]
## Ideally a star of $6\text{-}8$ solar masses.
Very massive stars are *not* the best choice, for two reasons. The first one is that these stars tend to be quite violent during their lives, with strong stellar winds and sometimes energetic non-thermal radiation, like x-rays. Adding shielding to a megastructure like a Shkadov thruster might be possible, but it's a pain. Plus, after some millions of years, if the star is heavier than 8 solar masses, it'll explode in a supernova, and *there's a very good chance that your thruster will simply be destroyed* in intergalactic space.
The second reason is that for stars of above $2M\_{\odot}$, the final velocity a star can produce throughout the entirety of its lifetime is essentially independent of mass, for a reasonable mass-luminosity relation.$^{\dagger}$ We can actually do these calculations by simply invoking conservation of energy, following the method of [Hooper 2018](https://arxiv.org/abs/1806.05203), who applied to to propelling stars using energy gathered by Dyson spheres. The argument there is one of conservation of energy. The final velocity $v$ after a thruster has operated for time $\Delta t$ is, for stars of $M>2M\_{\odot}$,
$$v=0.034c\;\left(\frac{\Delta t}{1\;\text{Gyr}}\right)^{1/2}\left(\frac{M}{2M\_{\odot}}\right)^{1.25}\left(\frac{\eta}{1}\right)^{1/2}$$
where $\eta$ is some efficiency factor. Let's assume our star will die before we reach Andromeda, an assumption I think should hold for all stars of $M>6M\_{\odot}$$^{\ddagger}$. The lifetime of the star scales as $\tau\propto M^{-2.5}$, and so if we assume that $\Delta t=\tau$, we see that the mass dependence for $v$ actually drops right out!
Let's assume, then, that the mass of the star is unimportant for the stars of the masses we're interested in. I then argue that we should pick a star in the range $6M\_{\odot}<M<8M\_{\odot}$. Why? There are a couple of reasons:
* A star more massive than $8M\_{\odot}$ will undergo a supernova prior to arriving at Andromeda.
* A star less massive than $6M\_{\odot}$ will not have had its full energy tapped by the time it arrives at Andromeda.
* A less massive star lives for a longer period of time, and therefore it can be a source of auxiliary power for other thruster functions for longer.
* Stars in this mass range are much less likely to have outbursts and eruptions than the massive stars others have argued for.
In short, pick a star of moderate mass, and you'll reach Andromeda efficiently and, most importantly, without having been incinerated by a supernova.
---
$^{\dagger}$L.Dutch notes a break in the mass-luminosity relation for $M>55M\_{\odot}$, though I'm not sure that this is widely-used, and at any rate, these stars are *extremely* rare.
$^{\ddagger}$I got this value by assuming that all stars of $M>2M\_{\odot}$ reach terminal speeds of $v\_{\text{max}}\approx0.045c$ (which you can see by a quick calculation using the above formula) and would have mean speeds of approximately half that. The travel time to Andromeda is then roughly 114 million years, and a star of mass $M=6M\_{\odot}$ would leave the main sequence after that time - I neglect main sequence evolution.
[Answer]
Instead of using a Shdakov thruster, use... The Caplan thruster! A hypothetical megastructure that essentially acts as an immense rocket, shooting stuff one way to propel yourself the other way. This requires a basic Dyson swarm first. Since your civilisation can construct Shdakov thrusters only through probes, I'm going to assume that they have the capability to create a Dyson swarm.
A Caplan thruster is a space station-like megastructure pointing towards the sun that draws on energy from the Dyson swarm and gathers solar matter, powering nuclear fusion which ejects particles from its 'thruster' at around 1% the speed of light. A secondary thruster fires a second jet of particles at the sun, pushing it forward so the power of the primary thruster doesn't cause the Caplan megastructure to impact the Sun.
To quote from the paper, which I will link.
'A jet with the mass loss rate m and average speed (v) gives the sun an acceleration of m(v)/M⊙'
To maximise the acceleration, or *a*, you must increase *m* and *(v)* without *m* being large enough to impact the lifespan of the star.
The Caplan thruster uses immense electromagnetic fields to gather hydrogen and helium from the sun, since it requires millions of tons of fuel a second. However this sparse interstellar matter is not enough to power the Caplan thruster alone. This is where we will use the Dyson swarm. The swarm will focus sunlight onto the star itself, heating these areas to incredible temperatures and causing millions upon millions of tons of matter to rise from the star, which will be funneled into the Caplan thruster using its electromagnetic fields.
The helium and hydrogen are separated, where the helium is used in thermonuclear fusion reactors, with primary thruster expelling radioactive oxygen at a billion degrees. The secondary thruster works by using particle accelerators to fire the collected hydrogen back at the sun, balancing out the Caplan thruster to prevent it crashing into the surface. The star can be moved 50 light years in only one million years.
The use of stellar matter will also extend the lifespan of the star, since smaller stars undergo fusion at a slower rate.
If we assume a perfectly efficient Dyson Swarm, in only 5 Megayears the star could reach velocities of up to 200km/s as opposed to the 20km/s that Shdakov thrusters reach after an even longer period of time, however the mass loss rate limits the usage of the star to 100 megayears of use before the star becomes impacted enough as to limit performance and shrink.
It's more viable to redirect the star onto the trajectory you wish for it to travel, firing the Caplan thruster for only 10 megayears in that direction.
I know this isn't directly answering your question but I think that a Caplan thruster is currently the best way to go about stellar engines>
Link to the paper: [link](https://sites.google.com/view/m-caplan-stellar-engines/startseite)
[Answer]
An unnatural one.
L.Dutch's answer is a good start. If you just want to find a natural star to ride along with, something in 55-60 solar mass range is fine. And indeed, that is a good place to *start*....
But you can do much better than just finding a natural star and riding along. After all, you've already got the technology to build a Shkadov thruster, and you've got millions of years and a whole stellar system of resources to continue developing.
Stars increase in luminosity throughout their lifespans, as the core becomes more compact and fusion gets faster. The final supernova is kind of just the endpoint of that continuous process... and kind of a huge waste, as well.
If you can lift material off the star as it ages during the journey, you can arrest the luminosity increase and extend its lifetime. That mass then has a variety of uses. You can use it as reaction mass to improve your propulsion efficiency and get to Andromeda faster. You can use it to slowly build a companion star that will provide additional power output and improved thrust. Or you can save it to feed back into the original star later when it starts to *actually* run out of fuel.
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[Question]
[
[](https://i.stack.imgur.com/lYFdp.png)
Amino acids, the building blocks of proteins and, therefore, one of the key components of life as we know it.
There are many amino acids in nature, but they all stem from the same basic structure.
They can polymerize into proteins, complex with metals, and bind to other important compounds.
However, they are have downsides, a limited temperature range, sensitive to strong acids, bases, and oxidizers.
My question is, what known polymers could aliens use in place of amino acids and what conditions would favor the use of those polymers?
[Answer]
>
> My question is, what known polymers could aliens use in place of amino acids and what conditions would favor the use of those polymers?
>
>
>
There are currently zero *known* polymers that have the ability to do what amino acids could do. Theoretical? Sure - at least, to some extent. All amino acids are really just building blocks. When you get down to it, really no different than the periodic table of elements. Or LEGOs, for that matter. There are twenty amino acids, and they each have pretty unique properties, but it's not the individual amino acids that make it interesting, it's the *combinations* that make it interesting.
And part of what makes amino acids so incredibly versatile are the restrictions you mention. They're sensitive to strong bases and acids because they contain a base and an acid themselves, not to mention that some R chains also have acidic properties, alongside polar ones, and that's what makes them capable of forming complex structures. Not to mention that, given how unbelievably complicated protein folding is, there's no reason for any practical field of science to try and create a system that can replicate proteins from scratch, especially when it probably won't react well with biology as it stands.
Not to mention that, at least as far as we understand it, the current system is a really good system - evolution, if nothing else, can sharpen knives really well. If you're looking for a system that can do everything amino acids can do, then you're better off using amino acids. Uprooting the entire system and replacing it isn't going to function well.
Unless, of course, you're asking about how you keep the system of the amino acids but play around with the molecule so that it's suitably foreign / alien. In that case, you might want to swap some of those elements around. Trade the acid / base groups on either end for something a bit more exotic - maybe the amino group is now a thiol, and therefore is sulfur-based, not nitrogen based. Maybe the carboxyl group is now an alkyl halide. Maybe you've swapped all the carbon for silicon - why? Well, because of element availability, of course. Your planet has undergone organic chemistry based on these groups as opposed to other because of their relative abundance.
Now, I will point out that, in actuality, it's a lot more complex than to simply be able to say 'They're like us, but their amino acids have thiols instead of amines', but unless you're working hard sci-fi, something like that would be fine. Also, it'd be called 'thiolo acids' instead, because you've replaced the amine group with a thiol.
[Answer]
**RNA.**
[](https://i.stack.imgur.com/rEhvD.png)
RNA is a fine polymer. The amino acid equivalents are cytosine, guanine, adenine and uracil. RNA still comes in handy for life today. The RNA polymer can (and does!) do many of the activities proteins can do including enzymatic activities.
RNA-based life (without proteins or DNA) is thought to have preceded life as we know it today.
<https://en.wikipedia.org/wiki/RNA_world>
>
> The RNA world is a hypothetical stage in the evolutionary history of
> life on Earth, in which self-replicating RNA molecules proliferated
> before the evolution of DNA and proteins...
> Alexander Rich first proposed the concept of the RNA world in 1962, and Walter Gilbert coined the term in 1986. Alternative chemical
> paths to life have been proposed, and RNA-based life may not have
> been the first life to exist. Even so, the evidence for an RNA
> world is strong enough that the hypothesis has gained wide
> acceptance.
>
>
> Like DNA, RNA can store and replicate genetic information; like
> protein enzymes, RNA enzymes (ribozymes) can catalyze (start or
> accelerate) chemical reactions that are critical for life. One of
> the most critical components of cells, the ribosome, is composed
> primarily of RNA. Ribonucleotide moieties in many coenzymes, such as
> Acetyl-CoA, NADH, FADH and F420, may be surviving remnants of
> covalently bound coenzymes in an RNA world.
>
>
> If the RNA world existed, it was probably followed by an age
> characterized by the evolution of ribonucleoproteins (RNP world),[2]
> which in turn ushered in the era of DNA and longer proteins.
>
>
>
So no scifi: a real, existing alternative to amino acids and protein polymers.
[Answer]
Thiolins might work.
Thiolins are a complex range or organic polymers thought to exist on the surface of Titan and other astronomical bodies.
[](https://i.stack.imgur.com/lGy7O.png)
Tholins are disordered polymer-like materials made of repeating chains of linked subunits and complex combinations of functional groups. The properties of tholins will depend on the energy source used and the initial abundances of precursors.
There are probably a large number of alternatives that could be used as the scope of chemistry is huge and humanity is aware of only a tiny fraction of the vast array of possible chemical permutations and combinations.
<https://en.wikipedia.org/wiki/Tholin>
[Answer]
Heres my analysis: As was mentioned before, natural systems make use of amino acids almost exclusively to make stuff that does stuff.
Why the particular 20 that they do?
Well, its biology we are talking about here so partly due to dumb chance. Apart from that- you need the side chains to perform certain functions that allow your enzymes to work and structural proteins and whatnot to do the same: you need acidic bits and alkaline bits (ideally of differing strengths as well). You need hydrophobic bits to make parts of your proteins despise their surroundings and bunch together. You need sulfurous and other (eg. imidazole) bits as ligands to bind metals for catalysis, redox reactions etc, disulfide bridge formation (or an equivalent kinda strongish covalent interaction) is a nice bonus. Some do side hustles, like histidine being able to take a proton from one side and release another on the other side (acting like a hydrogen shuttle)...
and the fewer side groups, ie specific building blocks, you are going to achieve all the required functionality with, the more efficient and simple your system will be- which are good things.
As for the backbone itself, the current design (the amino and acid bits themselves, and the amide bond they form)....
well youd probably want the alternative to be as stable as possible (would not trust the aforementioned thio compounds with that), capable of forming a strong non-covalent interaction with itself (hydrogen bonds are the tried and true method, halogen bonds and pi-pi interactions seem like possible alternatives)- and all that in as small a package as possible (to get the best atom economy, the lightest overall system...).
I am not sure as for the rigidity of the backbone- most single bonds can be freely rotated about, the CO-NH peptide bond being an exception.
Something like a CR2-NH-CR2- repeating unit would form H bonds, would have even better atom economy than amino acids and would be significantly more stable chemically (capable of operating in strongly alkaline conditions) but might be too floppy for reliable folding.
A poly pyrimidine ether or amine would make for a rigid backbone, high chemical and radiation resistance, and possibly strong H bonds, but might bee too rigid or bulky for proper folding itself...
all in all any polymeric backbone could be made to work: nucleic acids, polysacharides, polyamides... you could just use polyethylene and stick side chains that do the directed bonding on it instead. The question then is how straightforward, efficient and capable you want your system to be.
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How and out of what could flexible, thin air-tight tubes be made of at around 1780? These tubes need to be around a centimeter wide, with a 7.5 mm tube going through it. It must also be heat resistant (steam temperature) and be air-tight.
also, it would be helpful if someone could give me some lightweight but heat resistant metals, although I can do this research by myself.
[Answer]
**Leather.**
[](https://i.stack.imgur.com/8gCOW.jpg)
Image source: <http://tarasauvage.com/wordpress1/a-fireman-fire-hose-the-inspirational-story-of-ignition-supply-co/>
Leather fire hoses were invented in the 1600s.
<https://en.m.wikipedia.org/wiki/Fire_hose>
These were as strong as their seams, and were even stronger once rivets were used instead of sewn seams. You could wrap a leather hose with cordage to increase its pressure tolerance.
As regards metals, they are all heat resistant. Brass and bronze are lighter than iron and are good for making metal parts.
[Answer]
I'm pretty sure the intestines of an animal would meet the requirements as described in the question, if properly treated. But I don't think they'd *last* for very long with steam being pumped through them, and I wouldn't want to be in the same room.
Also, in the comments it sounds like you're trying to power some kind of steam engine, for which purpose the elasticity of intestines would be a problem.
You could try impregnating a length of intestine with rubber, vulcanizing it ([though that's anachronistic](https://en.wikipedia.org/wiki/Sulfur_vulcanization#Modern_developments)), and then braiding an outer sheath from metal wire. You'll want to test this in your kitchen to know if it actually works.
[Answer]
Rubber was discovered in [1770](https://www.scienceandinventions.com/who-discovered-rubber/) and has a melting point of [180 C](https://www.reference.com/science/melting-point-rubber-7866027e204cc4a4). Its true that the working of rubber into useful shapes didn't come until ~100 years later, but it was there.
[Answer]
A composite material - Think of belted tyres. They are made of rubber with steel reinforcement.
Your pipe is made-up of a fabric, made entirely out of steel fibers. The inner lining is rubber, as said earlier.
Rubber - Makes it airtight/watertight
Steel wires - Reinforces the pipe. Steel wires mesh is flexible to some extent. Think of a shower hose made of a metallic helix and the rubber pipe inside it.
[](https://i.stack.imgur.com/h3EHG.jpg)
(C) <http://www.visualdictionaryonline.com>
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I've spent a good deal of time working through the mechanics of 'realistic' space combat, and figure that good old kinetic projectiles will probably still at least be part of the arsenal, if not the primary weapon. The effectiveness of such weapons, however, is mostly dependent on the muzzle velocity. Let's assume we're using coilguns, to get around the friction problems inherent in a railgun. The question is: How powerful can we theoretically get them?
For reference, let's use the U.S. Navy railgun project. From what I understand, they plan on firing a 10kg projectile at about 2.5 km/s from a gun barrel about 10m long, for an acceleration on the projectile of about 31250 g's. Let's use that as our modern-day benchmark. Because of the way the distance / acceleration equations pan out, in order to get twice the muzzle velocity, we need either four times the length or four times the acceleration. If I assume that coilgun acceleration technology improves at a rate of 1% per year and that my ships are being built about 200 years from now, then we could expect to get guns with about 7.3 times the acceleration of today's railgun, for an acceleration of 228125 g's. If my gun barrels are 100m long, then that would give us a muzzle velocity of about 21 km/s. Is this a reasonable set of assumptions to work off of? What would go wrong?
Also, the 10kg projectile used today is rather small for what I want them to do. Can I increase the mass of the projectile without decreasing the muzzle velocity? If such a technique exists, could I use it to also increase the muzzle velocity beyond the rather tepid (by sci-fi standards) 21 km/s that I've already got?
EDIT: Ideally, I'd like a way to justify having 100 meter long guns be able to throw out 1-ton projectiles at 30 km/s or better. If they could get up to 100 km/s, that would be fantastic.
[Answer]
>
> I'd like a way to justify having 100 meter long guns be able to throw out 1-ton projectiles at 30 km/s or better
>
>
>
I don't understand your strange "tons", so lets use a nice easy measurement like a tonne. Your projectile will leave the barrel with a hefty $4.5\*10^{11}$ joules of kinetic energy. If your coilgun only wastes 1% of that energy in heating the projectile, 4.5 gigajoules of energy will be absorbed by it (a little over the energy released by the detonation of a tonne of TNT, as it happens). The specific heat capacity of iron (for example) is 450 joules per kilo per degree, and it has a melting point of 1811K. From a starting point of a comfy 293K, it'll take $6.6\*10^8$ joules to raise a tonne of iron to its melting point. The latent heat of fusion for iron is 247kJ/kg, or $2.47\*10^8$ joules. You will note therefore that the energy required to melt a tonne of iron is an order of magnitude *lower* than that 1% waste heat.
In theory, then, your gun will explode immediately. You'll also find that you just heat your projectile up to its curie point and then you'll have real problems accelerating it further (or possibly at all), though I expect you'll still be able to heat it up just fine. Hopefully it won't hit the walls of your gun. Hopefully also your gun doesn't have problems with "dry firing"!
Problem one, then, the inductive heating of the projectile is gonna have to be hella low. Your coilgun is probably going to have to be >99% efficient.
---
Next, lets hazard a guess at the capabilities of your coilgun using a lazy trick from Luke Campbell (which I found on the ever-useful [project rho](http://www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Kinetic_Kill_Weapons--Coil_Guns)). It isn't quite realistic, but it does give ballpark figures for the performance and plausibility of your magnetic guns.
>
> Now assume that the barrel is filled with field, and that the projectile sweeps the field out of the barrel, turning the field energy into kinetic energy (this is not actually how coilguns work, but it gives the physical upper limit based on energy conservation). The energy density is about 400 kJ/m3/T2 times the square of the magnetic field strength (398,098 J/m3/T2 to six significant figures). Call this value K.
>
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> You now know the volume needed in the barrel based on how much energy the projectile ends up with
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> volume = kinetic energy / (K \* (magnetic field)^2)
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Lets imagine the barrel is 30cm across (a one tonne iron projectile would therefore be a little under 2m long). The swept volume of the projectile as it traverses a 100m barrel is therefore about 7.07 cubic metres.
Using the above formula, you're gonna need a magnetic field strength of 400T. That's *a lot*. This is *waaaay* above the magnetic saturation point for an iron projectile (1-2 tesla), higher even than the saturation point of a modern "high"-temperature superconductor (100-200T). You'll need to handwave greater-than-room-temperature superconductors to deal with that kind of field. Remember that if your field strength exceeds your superconductor's [critical field](https://en.wikipedia.org/wiki/Critical_field) the superconductivity goes away, and your gun will probably go bang, in a very bad way. Also remember that the dumb iron projectile mentioned above is a lot more tolerant of serious heating than your fancy superconductors, which will probably stop superconducting at much power temperatures than the curie point of iron. Your inductive heating requirements become even more stringent, which implies even *greater* efficiency required of an already stupendously efficient system.
Problem 2, then, is materials science. You're gonna need some absurdly optimistic super high temperature supercondutors to make this work.
(also, I hope you're just throwing dumb projectiles here. good luck getting any technology to survive the acceleration, heating and magnetic fields you're subjecting the projectile to here)
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>
> If they could get up to 100 km/s, that would be fantastic.
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If by "fantastic" you mean "solidly within the realms of fantasy" then you're in luck! The energy levels you'll need to deal with are a good two orders of magnitude greater. Your superconductors and projectile will need to be made out of fairydust.
Problem three: you're already waaay out at the bleeding edge of what appears to be possible. You can't really go any further.
---
There are of course further problems related to the sheer amount of power you're going to have to throw at your gun to get it to boost the projectile to the required speed, the size and complexity of the associated ultracapacitor technology (which will go boom big time if damaged whilst charged!), the sheer amount of power your switches are going to have to handle in order to turn the acceleration coils on and off fast enough, the power generation requirements of your ship, the necessary heat rejection capability, and so on and so on. I think you're going to be disappointed, sorry.
[Answer]
So it's probably important to explain a few things here about physics and Newton's Laws. The whole point of a railgun is to be able to do a lot of damage with a smaller projectile by giving it far more velocity.
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> Momentum = Mass x Velocity
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In this equation, what we're saying is that you can increase the damage caused in a collision with something in two ways; you can increase mass, or you can increase velocity. Actually, you can also do both if you like and that's what you're trying to do by having heavier ammo, but to what end?
Remember that in space in particular, any form of launch of ammunition, even a railgun, is also a thrust vector. That means, that if you increase the mass of the bullet that you're already accelerating to very high speeds, you're changing the vector of your ship in the process by pushing it away from the direction you're attacking. Not to mention of course that improving launch acceleration of the projectile while also increasing its mass means harnessing orders of magnitude more energy on the scale you're talking about.
Is it possible? Yes, of course it's possible. BUT, do to it you're effectively reinventing the battleship in space. These massive guns are going to push boats around quite a bit out there and as such, you're effectively going to need a massive boat just to keep things steady as you fire. That's probably a good thing because your boat has to be capable of holding incredible amounts of energy so probably houses some form of fusion reactor or banks of capacitors that make modern industrial batteries look like phone charging banks.
The important thing to note is the equation for energy;
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> Energy = 1/2 x Mass x Velocity2
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What that means is that your energy requirements are proportional to the square of the velocity you want to achieve, and that the more mass you're accelerating, the more energy you have to put in. So, increasing your projectile weight by 100 means you need 50 times more energy just to give the projectile the same velocity, and to increase the velocity by 10 times you need another 100 times, so you now need a ship capable of unleashing 5,000 times the energy of the original railgun to get your ton of projectile to 100km/s - doable but very dangerous.
Ultimately, the size of the barrel is only important in terms of the speed at which you can impart the energy. Is 100m reasonable? I don't know enough about the technology to say but the point being that you have just increased your energy requirement by 5,000 and only increased your barrel size by a factor of 10, meaning that your new barrel has to be able to impart 500x the energy density (or 500x the energy per set length of barrel) as the original design.
If you get it working, the relative impact is going to be incredible and you'd be able to wipe out old ships with no problem, but just bear in mind that if you need a ship hundreds of times larger to run the guns, so does your enemy meaning that it may look impressive, but it's likely going to be just as hard to shoot the enemy down with these bad boys in your more modern context as it would have been with the current technology.
[Answer]
Muzzle velocities may be more modest than your projected velocity of 21 km/s. When Gerard O'Neill was conducting trials with mass-drivers. This was pioneering work for the construction of his proposed Lagrange cylinder habitats. This research found there was a limiting velocity of around 4 km/s. After which any projectile launched with a mass-river tended to (a) reach a limit where the electromagnetic field could not transfer more momentum to the projectiles, and (b) wreck the mass-driver.
Coil-gun technology might be better at launching projectiles at higher velocities than mass-drivers, and making sure projectiles continued moving in a straight line without making contact with the walls of the coil-gun.
You may need to take into account there could be practical limits to what can be achieved by coil-guns. This is based on empirical trials with mass-drivers.
] |
[Question]
[
Basically, the problem is I want to leave behind isolated pockets of survivors. Also, I want these survivors to be a primitive culture - current real world level - compared to the original civilization (which was Kardashev type III. The survivors (several generations into the future) must not know that there was such a civilization before them.
What i thought of until now -
Just like we have cultures like those on the Sentinel Islands, which do not know anything about us we could have people who inhabited other star systems and simply lost contact with the rest of the civilization. But that did not seem very convincing (since even they would have a level of development higher than ours).
[Answer]
The human mind is more limited than the AI we can create. In our life span, we can only learn so much, achieve so much, and contain so much info, but a benevolent AI can spend tens of thousands of years learning and expanding its own capabilities. At some point the human mind will become too limited to conceive the sciences needed to advance our technology, but our AIs will continue to move us forward.
Imagine a future in which each world is governed by a master AI which is connected to an interplanetary network designed share the collective knowledge of the universe so that each planet has access to all the tech they will ever need. Then one day something goes wrong, either a human hacker that hates the supremacy of AI or maybe even a rogue planetary AI conceives a virus that spreads itself across the interplanetary network wiping out all of these AIs.
With the AIs gone, we have no interface for our old technology. We forget about it quickly because it's all based on transdimensional and nanoscopic tech that is so unstable and small that it all just collapses into dust in the wind or flies out of existence as it drifts uncontrollably into parallel dimensions.
Human hobbyists who studied the technologies of old Earth can piece together a new civilization based on what the human mind can know, but most tech is lost because we were simply never able to conceive it to be able to recreate it.
[Answer]
It doesn't matter.
The civilization fell. The inhabitants forgot everything. It is *now* irrelevant why and how exactly it fell; it is irrelevant because nobody knows, so the specifics of the decline and fall are now lost in the mist of time.
Examples:
* There was once a [great power](https://en.wikipedia.org/wiki/Egyptian_Empire) in the Levant, which endured for thousands and thousands of years. But eventually it fell on hard times, and it became easy to conquer, and in due course it was conquered by the Persians, who were later conquered by the Greeks, who were later conquered by the Romans, who were later conquered by the Arabs, who were later conquered by the Turks.
When it came to pass that the [French invaded the country](https://en.wikipedia.org/wiki/French_campaign_in_Egypt_and_Syria) and defeated the Turks, they found that the inhabitants had forgotten everything about the rich and resplendant civilization which had once flourished there. They had forgotten its name, they had forgotten its language, they had forgotten the great victories and the names of the glorious rulers. The impoverished peasants who inhabited the land called it Misr, using the name given by the Arabs; at least the French used an older name, Aigyptos, Egypt, bestowed by the Greeks two thousand years earlier. The original name, Kemet, was found out only in the 20th century.
* There was once a [great civilization](https://en.wikipedia.org/wiki/Hittites) in Asia Minor, who rivalled the power of Egypt, and which endured many centuries. But eventually it fell, and its lands changed hands from conqueror to conqueror. When its royal archive was discovered accidentally in the 19th century by a [German scholar](https://en.wikipedia.org/wiki/Hugo_Winckler), *nothing* was known about its former glory. *Nothing.* Not its name, not its language, not its history. The German scholar calleed it "Hittite", using the name of a mysterious nation mentioned in passing in the sacred books of the Hebrews and which had appeared from time to time in ancient inscriptions.
* There was once a rich and vibrant [trading civilization](https://en.wikipedia.org/wiki/Mycenaean_Greece) in and around the Egean, with advanced architecture, and writing, and art; it endured for a long time, but eventually it fell, and while it was not *completely* forgotten all the details of its fall were lost. People only remembered, vaguely, that it had existed, and half-remembered the names of its former cities and kings.
What all these have in common is that their downfall was caused by one event, of which we know almost nothing. We call it the [Late Bronze Age Collapse](https://en.wikipedia.org/wiki/Late_Bronze_Age_collapse), we know that is was sudden, brutal and definitive, and we know that it happened at some point between 1200 and 1150 BCE. In the words of the American historian [Robert Drews](https://en.wikipedia.org/wiki/Robert_Drews) as quoted by Wikipedia:
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> Within a period of forty to fifty years at the end of the thirteenth and the beginning of the twelfth century almost every significant city in the eastern Mediterranean world was destroyed, many of them never to be occupied again.
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And that's about all we know about an event which ended several major civilizations here on Earth, an event which was of the utmost importance in the eventual rise of our own civilization on their ruins. We have several fragmentary indications that what we call the Late Bronze Age Collapse was in some way linked to an invasion, or a migration, by a group of people whom the ancients called the [Sea Peoples](https://en.wikipedia.org/wiki/Sea_Peoples), but we don't know who they were and were they came from, and actually we are not even certain if they were conquerors or displaced refugees pushed by desperation.
In fiction, this device is used for example in [S. M. Stirling](https://en.wikipedia.org/wiki/S.M._Stirling)'s series [*The General*](https://en.wikipedia.org/wiki/The_General_series). The series follows the adventures of Raj Whitehall, a general in the service of the Civil Government, who attempts to re-unite the half-barbarian kingdoms of Bellevue, a planet which had been once a member of a star-spanning Terran Federation. The most civilized of the inhabitants sort-of remember that the Federation had once existed, but they know nothing about its nature or why it fell. As a sop to the readers, the sole surviving A.I. -- who is helping Raj in his efforts -- mentions (halfway through the fourth book in the series) that the Federation fell because something called the Tanaki Spatial Displacement Network was destroyed, or maybe it was shut down, and in any case all contact was lost with the rest of the Federation, and eventually a civil war ensued, and very powerful, possibly nuclear, weapons were used.
And that's it: nothing more is said, because nothing more would be relevant. There was once a Terran Federation, and it is no more; its technology has been lost, its language has been lost, its culture has been lost. The people living in the times when the story is set know that they are living in fallen times and not much more, so no purpose would be served by providing more details.
[Answer]
### There are many phenomena that hit densely populated, civilized areas more harshly than primitive, isolated ones:
* **Disease**: a hard-to-detect, fast-spreading plague quickly reaches all planets with major spaceports within a couple of weeks. By the time transportation is closed, busy planets have already been exposed beyond the point of no return. Any survivors are effectively abandoned in an empty world. Small, relatively uninhabited planets have fewer scheduled deliveries and have time to close borders before too many infected arrive.
* **Terrorism**: a powerful, secretive cult plants agents all over the galaxy's most populated areas, each carrying a kilogram of antimatter held in magnetic suspension tanks. At the scheduled time, all the agents detonate their explosives simultaneously, scorching the surface of the most advanced, populated planets.
* **Technology**: a rogue artificial intelligence spreads across the civilization, taking control of all technology, from hovercars to nuclear reactors, and uses it to inflict the most damage possible on society. Great cities are reduced to rubble, but small hippie communes are unscathed.
### The result:
* Once most of the galactic hubs of commerce, manufacturing and transportation are destroyed, small areas that grew dependent on them will quickly regress into a primitive culture.
* Generations later, children will have no real memory of anything associated with the old civilization. It may be a religion to them, or a bedtime story.
* These pockets of primitive life are so small that they can't recover enough of the technological knowledge of their ancestors to make it to space, so they remain isolated until they each independently rediscover space travel.
[Answer]
**Only the slaves survive.**
Your advanced civilizations had other species that they kept as slaves - possibly one or more intelligent species from various worlds in their federation. Or possibly these are just a different race of the same species as the masters. These slaves were not educated, taught to read or even to repair or use technology; perhaps they were used for agriculture or mining in circumstances not conducive to mechanizations. In the rural hinterlands, slave populations were allowed to reproduce and grow to provide a steady supply of slaves.
When the end came for this civilization, the slaves did not die. With all of the masters gone, the cities were overtaken by forest and the machines fell into disrepair and crumbled away.
The slaves continued on much as they did before, with subsistence agriculture, fishing and animal husbandry. Within a few hundred years, the old civilization exists only in legend.
[Answer]
At the moment I see two possible variants. It could be a damaged generation ship sent by your advanced civilisation before the collapse. With some damages to data storage, they would lack the historical society technological continuity. Depending on the social processes in the ship and after the landing, they may have very little memories of the original culture in couple of generations. Something like 'yes, we know we came in the great ship from the sky, but the ship itself isn't here, the ancestors disassembled it to build it capital; our nuclear power plant? yes, there are parts of the ship's engines there, but most of the stuff was reworked, melted down or thrown out'.
The second variant is a primitivist colony. Something like dieselpunk space Amish. Their ancestors wanted to keep old-world technologies and thought them to be the best. It's a natural right of a human (or whatever you are) to mine and burn hydrocarbons. For some time, dispatch ships from the main planets of your civilisation did come with the news and mail, then the ships stopped coming. Nobody really cared much about that.
[Answer]
Kardashev III civilisations are either multi-galactic, or they use something like Larry Niven's [Megasphere](https://en.wikipedia.org/wiki/Bigger_Than_Worlds), or a galaxy spanning swarm of [Dyson Spheres](https://en.wikipedia.org/wiki/Dyson_sphere), or they use a **lot** of [antimatter](https://en.wikipedia.org/wiki/Antimatter) in every inhabited environment in the empire. Assuming they live on planets and in space habitats all powered by matter-antimatter annihilation and have some form of FTL communications an act of terrorism on a unbelievable scale could be perpetrated by relatively few individuals who gain privileged access to systems they shouldn't be touching.
In short your primitive survivors are the lucky descendants of the few who were far away from the reactors that power their colonies on the day that the corrupt reactor alignment code went live. The disaster would be two fold in most places, first the huge explosions on the ground and then a rain of radioactive debris, the remains of orbital facilities blasted from orbit by their own failing reactors. It was a long climb back to modern levels of technology.
[Answer]
**DECLINE OF KNOWLEDGE**
As the civilization develops, increasingly AI handles more and more tasks better and faster than the aliens who built them. New designs technologies are developed through evolutionary processes, where different designs compete against each other in virtual environments through millions of mutating generations until a superior design is found. This also applies to new generations of AI and robots that eventually become vastly more intelligent than the aliens and handles all tasks that keep the civilization running. The aliens finally don't bother learning anything, since all answers, products, comforts, etc. can be had with a snap of the fingers (think Aladdin with a thousand genies).
The thing with evolutionary design is that it is very difficult to reverse engineer - you can see that it works better than what you had, but might not understand *why* it works better. Even the super-advanced AI can't tell.
Eventually, the AI may decide to leave the galaxy and abandon their originators - "what have they ever done for us", or they might enter some evolutionary blind road where they decline into something hyper-specialised that perfectly fits the parameters that they themselves set up, but isn't good for anything else. For whatever reason, they stop being there. The aliens are then left behind, surrounded by super-advanced technology that they don't understand, can't operate (there are no 'human' interfaces) and could never recreate. The quickly decline into very primitive cultures.
[Answer]
Rogue software. They were the victim of the ultimate computer virus or something of the sort. It spread through the networks at whatever their communications speed was, an infected system sent the bad instructions out before crashing, no warning can overtake the destruction.
Everything went down, total grid failure. While there might have been some isolated systems and skilled engineers that could have put things back together they didn't have a chance to actually do it because of the scale of the damage. You have a highly interconnected society dependent on machines that are now useless. The power is out, the water doesn't last much longer. There are no food shipments, no food production. People fight over what supplies are around, pretty soon the only source of food is cannibalism.
You will have a few survivors, though--hobbyists growing things the old way. Some will escape into nature areas with their seeds.
Why don't they quickly return to their previous tech level? It's normally figured the books would let society rebuild--but look at what's already happening. Books are dying--more and more we read electronic things. At one point there were thousands of books in this house--but I haven't bought a single book in half a dozen years now. Lots of e-books, no dead tree versions. Nobody learns from the books because they were in the computers and now are gone. There's probably backup media around with them--but no systems that can read it.
[Answer]
**On purpose.**
Whoever destroyed them left a few scattered worlds inhabited for humanitarian and/or PR reasons. But imposed on them lots of taboos on technology to make sure they never rise as a threat again. Monitoring was very close for a few centuries, with draconian enforcement. Think atomic non-proliferation on a *lot* of steroids. Nowadays it's more hands-off, but moon-mining would surely draw unwanted attention.
The people may or may not remember the origins of their taboos.
] |
[Question]
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To put this title into context, there are actually two basic kinds of angiosperms on Earth, showing here:
[](https://i.stack.imgur.com/C7e2Q.png)
These differences in characteristics serve their own adaptations to survive and thrive.
Now let's say there is a THIRD type of angiosperm, one whose embryo numbers, leaf veinage, vascular bundle arrangements, roots and floral part multiples are not the same as the other two. Realistically, as far as adaptations to cosmopolitan varieties of environments and climates go, what would the embryos, veins, vascular bundles, roots and flowers of the third type look like?
[Answer]
How About:
* Three cotyledons.
* A single vein down the main of the leaf with orthogonal feeder veins. giving the leaf a heavy central cylinder that the leaf essentially flops on either side of.
* Vascular Bundles usual organsied as a honeycomb, or latice like structure.
* Several Tap roots present. Average three though as high as five or six. For the three case the roots are angled off the vertical be roughly 30 degrees.
* Flower parts usually mirrored, preferring two, four, and eight part arrangements.
This would give you a distinct seed type, a reasonably functional vein structure, a rather sturdy tree probably good at resisting heavy weather due to the root spread, and an interesting flower form.
The only issue I can see are the leaves. This configuration would tend toward full leaf failure in the face of damage. Perhaps the leaves are generally more leathery? This would make the leaves more expensive biologically, but the theory would be that the leaf would resist damage, and be in use longer - similar to cacti and succulent leaves.
Is that what you are looking for?
[Answer]
I asked my brother-in-law, who knows a lot about plants, and he wrote:
Monocots and dicots both have only a single embryo per seed. The writer probably got confused by the double fertilization process of zygote and endosperm that occurs in both monocots and dicots.
There are a number of extinct and extant non-angiosperm plants that could easily be re-imagine as a "tricot". Among extant plants, *Gnetum* and *Welwitschia* are lesser known gymnosperms with unusual growth habits. Among extinct plants, some that don't have any present day equivalents include the Pteridosperms, Cycadeoidea, *Cordaites*, *Glossopteris*, *Lepidodendron*, *Archaeopteris*, *Chaloneria*, and *Sigillaria*. The characteristics of any of these could be "mixed and matched" into a "tricot".
[Answer]
Your third type of angiosperm could be a primitive angiosperm, aka **basal angiosperm**. Monocots and most dicots share a common ancestor, and this primitive angiosperm diverged from that line before monocots evolved. The primitive angiosperm will have some characteristics of monocots and some characteristics of dicots.
From <http://www.plantcell.org/content/20/9/2471>
[](https://i.stack.imgur.com/NFs45.png)
These organisms exist. They are called basal angiosperms because they are thought to be like the primitive ancestors of monocots and dicots. A good example is order [Nymphaeaceae](https://en.wikipedia.org/wiki/Nymphaeaceae), the water lilies.
[](https://i.stack.imgur.com/ZDGsL.jpg)
Here is a nice table summarizing the characteristics that interest you. I found it at <https://ucmp.berkeley.edu/glossary/gloss8/monocotdicot.html>
[](https://i.stack.imgur.com/O7fER.png)
For the water lilies, here are the characteristics. I labeled each with an M or D to show which category it is more like.
Embryo with 2 cotyledons fused into one (M+D)
Pollen with single pore (M)
Flower in multiples of three, or many. (?)
Leaf veins reticulated (D)
Vascular bundles scattered (M)
Roots develop from radicle (D)
Lack secondary growth (M)
So a mix of characteristics. There are other basal angiosperms but water lilies are good one for this. They are worldwide and live submerged / partly submerged in freshwater. They are wind pollinated or beetle pollinated.
Maybe since this is Worldbuilding you want something fictional. Well, purely aquatic habitats seems challenging for vascular plants. You could imagine an ancient angiosperm that somehow managed to deal with first brackish then salt water. These huge water lilies form forests like the kelp forests.
[Answer]
* Monocot: Simple structure.
* Dicot: More complex structure.
* Newcot: Fractal structure.
You can see the start of this in dicots. leaf veins have the start of some degree of self similarity.
Key factors of a more fractal structure will be increased self similarity at smaller scales.
Consider those big electrical metal towers. The early ones had heavy 4" right angle struts for the corner pieces, and a smaller one used for cross braces. Now there are about 4-5 sizes of braces. The braces have braces. And those braces have braces.
Complexity has increased, while weight of metal has decreased.
A fractal plant will have more leaf area per pound of plant. The one that comes to mind right now is asparagus.
Look at baneberry: It has thrice compound leaves -- a good example of fractal growth.
Evolution is a slow process.
I don't know that this will be the next Big Thing in Plants.
Whatever the next step is, it will become popular because it gives some serious advantage to that plant.
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[Question]
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So you can accelerate or reverse time of an inanimate/non sentient object within a limited space.
Despite having such powers, you don't want to rule the world. Instead you want to make alcoholic drinks.
Assuming you have only basic knowledge of making liquor of all kinds, how will your time related magic make you really good at making alcoholic drinks?
Additionally, how to become filthy rich in making liquors?
[Answer]
Making aged wine would be simpler than aged liquor.
Both wine and liquor can benefit from the ageing process. However, producing aged liquor (brandy, whiskey etc.) is technologically more complex and depends on the expertise of the distiller.
I recommend the following approach:
1. After the harvest, when young wine starts to hit the market, buy
samples of cheap wine from all around your region. The quality would
be mostly mediocre, but each wine would age differently.
2. Age all the samples for several years (wine time). Then open them up and invite a sommelier for a tasting session. Among your samples, some likely would be real hits.
3. Proceed to buy all supplies of young wine that would turn
into a "hit". Age the winners, present them at professional wine
events, and prepare for a lot of orders.
You can do essentially the same for liquors, but the process would be more complicated.
P.S. In premium liquors, manufacturers strive not just for an exceptional taste, but for the stability of it, meaning that they want to produce essentially the same taste for the range of years. In wines, no two years are the same. Restaurants would go for a good no-name wine, but not for a no-name liquor (even if taste is great).
P.P.S. If we focus on the **ancient** world, then if you character happens to know how to distill wine, he's all set for brisk business. Liquor was invented only in medieval times.
[Answer]
**This arrangement buys you one thing only: you're always first to market**
Which isn't enough to guarantee wealth. Here's the deal:
* Wine requires a nice grape - which has nothing to do with your magic.
* Wine requires a nice environment - which has nothing to do with your magic.
* Wine requires correct storage - which has nothing to do with your magic.
* Wine requires time to ferment - this has to do with your magic.
In other words, you have all the same problems of every other oenologist, but you can speed up the fermentation process (age the wine more quickly from the perspective of the wizard's reference frame).
And that means you can get it to market faster. But you don't have any more of it and you still need everything else to make good wine and one you've sold your lot — you're done making money.
**What about bank interest?**
No, not really a solution to the problem. Yes, you're getting the money into the bank sooner, but that's a benefit for only the first deposit. Every deposit after that occurs exactly one year later because you still need to grow the grapes, etc. So, you make a couple of extra bucks on the fist deposit's interest, but that's it.
**OK, but being first to market must count for something, doesn't it?**
No, not really, because everybody else is out there still making wine. They may be taking the traditional route — but there's still their wine to be purchased. They could always release last-year's wine in competition with your wine this year.
**So, how do I make an absolutely offensive amount of money with wine?**
1. Your magic multiplies the *amount* of wine you have so that you have more wine to sell.
2. Your magic improves the *quality* of the wine so you can sell it for more than your competitors.
[Answer]
I have quite a bit of experience in the Beer/Wine/Alcohol industry and here is my take. (Check out my reputation on [alcohol.stackexchange.com](https://alcohol.stackexchange.com/users/6111/farmersteve))
Wine could benefit from aging at two points, especially red wine. Barrel aging which can be up to 2-3 years in the barrel, then bottle aging, which can go on for 20+ years depending on the quality of the red wine. White wine only benefits from extended aging for a handful of years.
There are exceptions to this. Madeira and Port which can benefit from aging in the bottle for decades and the price goes up as they get older and older. I tasted a 200 year old Madeira a couple of years ago. Bottles were going for over $10,000 so that could be a way to reap the benefits.
The problem with wine is that it's once a year during grape harvest.
Booze can be made continuously as long as you have a supply of grain. Barrel aging Whisky enhances the value quite a bit and the longer it's in the barrel, the more valuable it gets. You would have to do some maintenance on the barrels of booze, topping up every few months so you would need to start and stop time. Whisky does not age once it's in the bottle, unlike wine.
Whisky is really probably where the money would be under this scheme because of the continuous nature of distilling booze. You could age a batch of Whisky every day to like 50 years and just repeat the process every day when you distilled more booze.
[Answer]
I never did the wine, but I made some homebrew whiskey and cognac. One secret you should know is that waiting for many years is not mandatory. Commercial production does it because it is convenient for them to do so: make a big barrel, put it in the cellar, forget for ten years.
When you make a small amount for yourself and friends, you use 5 liters barrel and you need to wait only for 4 month max. The time depends on the size of the barrel, or, to be more precise, on the ratio of inner surface to liquid volume. Or you can even speed up further by agitating the barrel regularly.
I even thought to use chemical ceramic magnetic mixer, but did not get to do it.
[Answer]
>
> So you can (...) reverse time of an inanimate/non sentient object (...).
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Ditch ordinary wine, that is just fermented grape juice that doesn't give you anything magical.
User your powers to make [Ghlen Livid from the Discworld](https://wiki.lspace.org/mediawiki/Reannual_plant), a drink that gives you glimpses of the future:
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> Reannual plants are an unusual sort of flora native to the Disc. It works like this: **when a farmer plants a reannual this year, the plant is harvested last year**. There are several challenges involved in doing so: for one, if you forget to sow the seeds after you harvest them, you risk disturbing the entire fabric of causality (although, as mentioned in Mort, causality is stronger than most people think). Thus, it takes farmers who are much given to introspection and close examination of the calendar (...), to pull it off correctly.
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> (...) The reannual Vul Nuts are mentioned in The Colour of Magic as being grown in the latter place, and when harvested they make a drink called Ghlen Livid. Mort's family specializes in making wine from reannual grapes, which cause their own problems, as you have the hangover the morning before, and have to drink quite a lot to get over it.
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> (...) Ghlen Livid is a spirit made from the freeze distilled Vul Nut, a reannual plant. **Reannuals travel back in time**, so Ghlen Livid **can give its drinkers a vision of the future, which is, from the nut's point of view, the past**.
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A hangover from such spirits is called a hangunder. No one knows what happens if you have a hangunder and are prevented from drinking afterwards...
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Out of season products.
Lots of comments on how to improve the actual brewing process, but what about the ingredients? You can get end-of-season grapes or hops - perhaps a delayed shipment from overseas - then *reverse time* for the produce to restore it to prime condition. Not all brewings/fermentations are designed to be aged, and you can serve these "Fresh" examples at *any* time of year.
Any fruit that is requires transportation is (certainly in *modern* times) picked before it is properly ripe, and then allowed to ripen in-transit. This has a noticeable impact on the taste of the end result.
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NB: *for more background, the humans of this question are the direct ancestors of the druids from [that question](https://worldbuilding.stackexchange.com/q/129626/52315).*
I am building the timeline of a druidic society which rose to dominate the forest they lived in, thank to their discovery of magic.
In particular, their ancestors discovered how to use mana to communicate with a sub-species of wolves.
Humans, like wolves, need to consume one specific species of berries which replaces the ability to see normal blue light with that of seeing mana. Once they do, skilled individuals become able to communicate telepathically, provided that they maintain eye contact. Note that this also works in the dark because "vision" of mana is not related to actual visible light. Naturally, wolves and humans can also use other forms of communication, but this telepathy has been the initial ingredient needed for both packs to understand each other.
The two groups cooperate for mutual protection and hunting, without one rising to tame or dometicate the other.
**In this scenario, what specific hunting strategies could the symbiotic group use to take advantage of this cooperation?**
Our usage of hunting dogs suggests that wolves could be used to track, flush or retrieve preys, leaving the killing part to humans. I am not certain however that this strategy has historically been adopted by humans prior to domestication and breeding into a docile species.
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**What do they each bring to the party?**
Humans and wolves are both optimised for [persistence hunting](https://en.wikipedia.org/wiki/Persistence_hunting). While this means that they have similarities that make it easier to relate to each other, it actually reduces the synergy from cooperative efforts - either species would be better off pairing up with species such as cheetahs or raptors. So let's look at the differences.
Humans are omnivores, tool users and sapient beings.
[Wolves](https://en.wikipedia.org/wiki/Wolf) are faster than humans over short distances, have a superior sense of smell (although inferior to many other canids) and an extremely powerful bite. They are primarily carnivores, but do consume some fruit and vegetable matter (including berries).
So some of the options for combining these abilities include:
* Gathering (not hunting) - wolves may be able to use their sense of smell to locate edible plants that the humans need more than the wolves do. While this is not cooperative hunting as per the question, it means that when hunting does occur the wolves can be given more of the meat. It is also important that the wolves can communicate specifically what plant/s they are smelling, they will not waste the humans' time on plants they currently have a surplus of.
* Detection and tracking - this is not significantly different to the current/historic use of hunting dogs, but the difference here is *communication*. Instead of having a dog indicating "Prey! (pant, pant, pant)" the wolf / wolves can communicate "Two deer" or "A pride of lions!"
* Channelling - humans can construct traps that the wolves will drive prey into. While humans can use this strategy on their own, in many types of terrain the low-profile wolves will be able to move much more quickly to get into flanking positions. Again, the difference is communication - a human does not need to move with the wolves to direct their actions. Conversely, the humans may initiate the attack against the prey and run the animal/s to exhaustion - right into the killing ground where the wolves are waiting.
The main difficulty with this scenario is the requirement that neither becomes dominant in the relationship. The simple fact is that where there is one party with animal instinct level thinking and one with sapience, the sapient party is going to end up calling the shots. Initially it may be for "the common good", but sooner or later it will end up being "for the humans' good". In order for the relationship to be equal, the wolves need to bring their share of brainpower to the party (something like the *kyree* in Mercedes Lackey's Valdemar series).
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**Working as one**
One of my friends goes bow hunting with a couple of native Bushmen. What he told me is each bushman had a dog. Now keep in mind that when i say dogs the dogs are closer to a wolf then your standard house dog. (the dogs where mixes between the native dog breed and a domesticated one) the dogs would track the prey until they were within firing range. Then the man would brush his hand down on the ground, the dogs would then lay low to the ground acting like the man’s shadow. The bushmen would take the shot and the two would go home with the kill.
He asked them what would happen if they missed (which never happened when my friend hunted with them) they said the dogs would then leap forward and chase the prey down and pin it, the men would then run a up and stab the prey in the heart to kill it (then the man who missed the shot would be punished for missing).
Fun fact the reason they mix the native dogs is because the native dog will not follow orders as well (or at all) but the mixed breed will. I found this out when I got to meet one myself. The dogs eyes would not look to where you point only follow your movements and almost never make eye contact with you (may be a plot hole in your own story).
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That would be hard to do on the fly. What could be better is this mana gives an area effect to the telepathically ability. Or a better idea is that the mana gives you the ability to sense other mana user’s intent (much like how the native dog works with the hunters) so your hunters would know what the wolves want to do and vice versa.
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Wolves are oh-so close, yet oh-so-far from dogs.
Dogs and wolves CAN interbreed, and their offspring can breed as well. This means that genetically, they really have some huge similarities going.
The definition of dog actually is "wolves acclimated to the presence of humans" And humans took that further by breeding for specific characteristics, as did Darwinism. HOWEVER, those wolves who could tolerate humans and benefited from following humans and hunting with them, well, those wolves already HAD a lot of the characteristics of dogs--because wild wolves DON'T.
As for them "communicating as equals" well...wolves can't talk. Humans can't really speak wolf. Telepathy would be more pictorial than language-based.
Now, as to how they would hunt--the leader of the pack isn't going to be in front. Like dogs, wolves put their leader in the middle or behind them, while they scout ahead. They are aware of what a leader is doing, and if they change direction, they will too, but it's generally the second in command that ranges ahead, checking back to see what the cues are.
Early on, they likely worked more closely with hunters and actually killed things. But wolves, and dogs are FAR more useful to point their human servants to something tasty. Humans take the risk, they get a percentage. It's a sweet deal. And for humans, with their spears and such, tooth and claw isn't the advantage. What is: the very special set of skills that wolves and dogs have that we do not--hearing, smell, and this case, a pack, which can work to corner prey so that the humans can finish it off.
The wolves following humans happened to have a particular set of genetics that made them less dangerous to humans, and more likely to retain "wolf pup" characteristics that are more like dogs in nature.
You CAN'T take a wild wolf and simply raise it to follow you, but IF a wolf pack has been naturally acclimated to humans that means that they are actually proto-dogs already.
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Depends on what you are hunting. Since hunting with dogs is legal in lots of places today in the real world, lets see how they are used. Not sure about other areas, but this is how I've seen dogs being used and actually used dogs for hunting here in north central Florida.
1 - hunting pigs, bears, other potentially dangerous things. Dogs/wolves go in and harrry and eventually catch the target, and keep it in place long enough for a human to go in and quickly kill/subdue/trap the target animal. Most often done with pigs around here, the pigs are then often kept and grain fed for a few weeks before being slaughtered and processed.
2 - hunting deer - many humans are in the woods, one human and dogs go "away" and then towards the humans in the woods, driving deer, etc. away from the chasing human/dogs/wolves and towards the hunters waiting. As deer go past, they get shot.
3 - retrieving in areas where humans won't do so well. Duck or goose hunting is a great example of this. In and out of cold swampy water. Or even in areas where humans do OK but it is more efficient to get some 4 legged help (retrieving dove, etc from grain fields)
4 - finding/pointing game (and then maybe retrieve or find after being shot). Look at upland bird hunters - pheasant, quail, etc. Humans and dogs work together to find birds. Dogs either hold at bird or get bird to go fly, bird gets shot, dog finds (and maybe retrieves) dead bird
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You don't need telepathy.
There are assorted instances of humans and predatory mammals cooperating without domestication or taming being involved, possibly the most famous being the orcas of [Eden, Australia](https://en.wikipedia.org/wiki/Killer_whales_of_Eden,_New_South_Wales). In that instance you had two intelligent predators cooperating; the orcas would alert the humans of a whale being present, the humans would kill the whale and leave portions for the orcas to eat (as well as being able to eat the smaller animals attracted to the kill).
One could easily imagine the same being done with wolves and, in fact, may have as the start of the domestication of the dog. Wolves alert the humans that prey is nearby and herd the prey animals toward the humans who are waiting in ambush. Humans kill more than they need and leave the excess to the wolves. It makes hunting easier for both--no need for trying to run prey down--and after both have had their fill they go their separate ways.
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Technically, all domesticated dogs are descended from the Asian Red Wolf. From that perspective, think of hunting with a pack of Alaskan Huskies.
I think a look at real life dog training principles and the experiences of wolf / wolf hybrid owners will be useful.
The pathway to domestication starts with a few individuals that have less fear of humans than normal, and lots of handling. Even pure wild stock wolves can be conditioned to see humans as alphas, but the handlers need to interact with them daily and enforce submission rituals on a regular basis - rubbing the belly of the animal is a prime example of exploiting a normal submission ritual (exposing the belly) too encourage behaviors.
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In my book series, a group of a few hundred explorers are sent from a planet called Ishgabangaloodoo to explore Sea World.
Some things to know about Ishgabangaloodoo:
* Its citizens are referred to as Ishgas
* It culturally resembles Victorian Britain but has technology on the level of Star Wars
* It is a planet city (think Coruscant from Star Wars)
* The Ishgas are the descendants of the Atlanteans (the ancient inhabitants of Sea World, but this history has been forgotten)
Some things to know about Sea World:
* The planet is almost completely underwater, with only a few scattered islands poking above the ocean surface. These islands are inhabited by the Dolphinesian (think native Hawaiian) and Platypusian (think Maori) Tribes, as well as a Kangaroo Island (think Aboriginal Australians) and a small pirate colony.
* The planet was not always like this, being relatively Earth-like until a magic ritual gone horribly wrong flooded the planet.
* The native civilization of the areas now underwater was the Atlantean Civilization. They built the remarkable, majestic, and ahead-of-its-time metropolis of Atlantea, but they left the planet for Ishgabangaloodoo 10,000 years earlier when the planet flooded.
* The Atlanteans placed waterproof domes over a little less than half of their city, but the city flooded too fast for them to protect the entire city, so they left.
* Underwater, civilizations of anthropomorphic fish (Reef City) and anthropomorphic crustaceans (The Lobster Empire) have sprung up. Both have Roman-level technology and organization, but the Lobsters are more aggressive.
Some things to know about the exploration team:
* The group of explorers numbers around 2,000
* The explorers have no desire to colonize the planet and are instead looking for artifacts of Atlantean History
* The explorers have built more waterproof domes over the parts of the city they are exploring
* The explorers, after unknowingly stealing an Atlantean artifact from their territory, have antagonized the Lobster Empire and this has resulted in a retaliatory raid that saw the lobsters stealing the explorers' entire stored food stash
* Since they were not expecting underwater civilizations, the Ishgas did not bring much with them in terms of weapons, so they have their hands full defending against lobster raids and patching leaks in their domes.
* Ishga crops will not grow in the sand at the bottom of the exploration domes, so farming in the domes is not an option
* The island civilizations are very hostile to outsiders and will not provide the Ishgas with food
* The Ishgas have access to 10 submarines as well as scuba suits that can provide the user with oxygen for up to 2 hours
* The Ishgas are operating in areas anywhere from 300-500 feet below the surface.
* Eating sentient beings is considered cannibalism, so they will not eat the corpses of dead Lobster Empire soldiers unless they get desperate
* Another food shipment from Ishgabangaloodoo would take about a month to arrive.
* The water temperature is around the same as that of the Caribbean.
Now for my question: Now that the Ishgas have been cut off from their food supply with no easy way to get it back, what will they survive on until more food from Ishgabangaloodoo?
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# The sensible option
No food supplies, hostile natives, unable to progress with their explorations until further supplies arrive? It's time to go home.
# The Victorian option
Since you have compared them to the Victorians, the other option is to do as the Victorians would have. Bribery. Since you have civilisations down there and civilisations run on money, find something you can use as money, bribe generals, suck up to princes. Hire locals as mercenaries and go to war. It shouldn't take them more than a few months to be effectively running the show. After which you start killing anyone who doesn't accept your bribes or back down from your technological superiority.
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Additional to Separatrix anser: Here are some more:
## The Researcher option
Look around, what do you see?
Any unintelligent sea animals like shells? see horses? ..
Any plants?
## The Sci-Fi-Techie option
There was the experimental 3D printer recipe for a food replicator / plankton-filter-protein-extractor ...
## The "Adventurers" option
Steal it from The Lobster Empire
## The Tomb Raider option
The 10.000 year old cookies in the perma frost layer around the old what-do-i-know-but-its-still-cold (refrigerator?) are still edible
## The Spy option
The lobster people, the fish people and all the others have to eat something (and don't tell me, the only eat one another). Just find out what.
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# The cannibal option
Food lasts until there is only one explorer left. [This may not be healthy](https://what-if.xkcd.com/105/), but hey, an emergency is an emergency.
I know the answer said they wouldn't eqt them lobsters unless desperate. My solution is for after the lobsters have been eaten too.
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Imagine a human observation and research facility being built on a planet in a distant solar system.
How could an alien colony exist beneath the planet's surface, staying completely invisible to humans on the ground? Let's say that aliens have a portal technology allowing them to travel from within the planet's insides to their home land at will and transporting resources back and forth - without ever touching the planet's surface.
Let's say their main goal for having the underground colony is resource extraction from the planet, and they want to stay invisible to avoid any conflicts if possible.
Could an alien colony be shielded to make it undetectable to human equipment either from afar and from up close?
Let's assume that the alien underground colony was built before humans came to the planet, so that main alien construction works were already done at that point.
Could it depend on passive sound and EMP proofing? Could it incorporate active silencing devices? The aliens still need to perform mining and ore processing inside of the planet, so that normally would be detectable by human equipment.
How could that be prevented? Using energy based mining tools instead of impact-based ones?
**EDIT 1:**
This question was marked as a potential duplicate of another one:
[How big could an alien-made object on the far side of the moon become so that discovery still can only happen by accident?](https://worldbuilding.stackexchange.com/questions/79058)
Though I think it's different, as the linked question asks about objects on the surface of the moon, while this question is about covering alien mining activity under a planet's surface.
To give more insight in my plot idea:
Humans have built an observation and research facility in a distant solar system - not knowing the planet is being mined by aliens, who have built a stealth outpost deep under the planet's surface. After a few years of operation the humans started drilling into the planet for research.
An alien colony hidden beneath have realized they cannot hide there for much longer without being discovered so they decided to attack, until they still have the upperhand of being unexpected - as evacuating and hiding all their traces was impossible to do.
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**The planet is crazy noisy already.**
This planet has loads of seismic activity and loads of volcanism. Maybe it is like Io, with a giant Jupiter equivalent wrenching and twisting it. You can hear it up through your feet when you are standing there. Seismographs return a chaotic roar. Or maybe meteorites regularly slam into the planet. Or the mammoth rock worms - they are native to the place, and their tunneling grinding noises sound a lot like the alien miners.
With any of these noise methods (go ahead, use them all!), it would be hard for the humans to distinguish some additional mining noise from the noise already on the planet and explained to the humans satisfaction.
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Considering the signals that an underground mining activity will produce, we can speculate on how to shield them (and what tech level is needed on the human side to detect them).
**Gravitational effects**
Removing large quantities of minerals from underground would reduce the local density of the crust. This would have a measurable gravitational effects, provided that there are atomic clocks and satellites.
Since gravity cannot be shielded, the only way to hide this is to avoid leaving hollow places and filling back the mines with something denser than air (the closest to the density of the abducted material, the better). P.S. This can explain why alien worlds are always so tidy, they have a garbage dump off their backyard.
**Noise**
Mining, if one uses what we human use, is going to be noisy. And a "clang clang tump" noise coming from underground would be noticed even by very primitive humans.
Active noise suppression might be a thing, or they could simply swipe the portal around, transporting large carrots to their home planet for further processing. Using the a second portal to send back the filler, as mentioned in the above point, would limit ground collapse, improving stealth effect.
**Underground circulation effects**
Depending on when the mining takes place, it can impact some aquifer, disrupting its circulation and maybe impacting also wells and springs above the surface, or, even worse, cutting through some touristic place like caves.
I guess for this careful prospection before mining is the only viable solution.
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An underground mine would remain undetected pretty much without any special precautions. Assuming they're not using heavy explosives, or anything like that, just drilling and excavating.
The ground is extremely good at blocking EM, so it will be safe from any scanners of that ilk. Same goes for acoustics, the noise will not couple well with air, so it'll be pretty much silent to any observer not specifically looking for it (you'd need to have sensors in/on the ground).
Biggest worry would be sensitive seismometers. For this reason you would want to avoid explosives, so you don't cause large scale shockwaves in the ground. Best defense will be distance, so you would want to locate your mine at least some tens of kilometers away from any settlement or geologically "interesting" location to be sure. The closer it is to any seismometers, the higher the risk become that it shows up and somebody gets curious.
Once someone gets curious the way you get found is via active echo mapping. Ground thumpers or explosives to generate shockwaves, the echos of which are picked up by sensors. The mine would show up as unexplained voids.
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# Planets are **big**. Incredibly **big**.
Sure, the colonists would have advanced sats in orbit, and advanced expert systems to analyze the imagery for clues, but there are likely many false positives to check out. Consider the [Cydonia Face](https://en.wikipedia.org/wiki/Cydonia_(region_of_Mars)), the [Baltic Sea Anomaly](https://en.wikipedia.org/wiki/Baltic_Sea_anomaly), the [Nazca Lines](https://en.wikipedia.org/wiki/Nazca_Lines), and the [Bimini Road](https://en.wikipedia.org/wiki/Bimini_Road). Only one out of four of my semi-random choices is generally considered to be artificial ...
Depening on the technology and orbital infrastructure, you might not even have to assume teleportation technology. With present-day technologies the superpowers are *somewhat* capable of [detecting missile launches](https://en.wikipedia.org/wiki/Space-Based_Infrared_System). Even so, the coverage of Russian missile fields and presumed [SSBN bastion areas](https://en.wikipedia.org/wiki/Ballistic_missile_submarine#Deployment_and_further_development) would be better than the coverage of Antarctica. It would be *conceivable* that a colony might miss a shuttle launch on the other side of the planet, especially if the aliens have "magical" drives without exhaust plumes.
You would have to assume that the aliens tried to avoid visible surface structures, but imagine e.g. a mine entrance under the trees of a jungle and "seaplane" shuttles landing on rivers, or a door in a cliff face.
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If the humans are moderately careful, the aliens will be found.
The aliens have to establish their underground mining colony in the first place. Unless they have such a high level of handwavium technology that they can blindly teleport to a location underground and excavate it in the process, they must have started on the surface. This means that they tunnelled down from somewhere near where the humans now have their base.
The use of [ground penetrating radar](https://en.wikipedia.org/wiki/Ground-penetrating_radar) has become standard in both archaeology and military surveying. While GPR has a limited penetration depth, it can easily identify disturbed earth near the surface - this is how it is used in archaeology to identify previously dug areas compared to untouched ground. (It is also used in murder investigations to identify disturbed ground that may be a grave.) Before setting up their research base, the humans would conduct a GPR survey of the surrounding area, both to identify any signs of previous occupation and possible current threats (like large tunnelling alien lifeforms). This will also probably lead to identifying tailings piles.
The other means by which the humans are likely to locate the alien mining colony, especially once they detect signs of excavation activity, is to set up an array of [seismometers](https://en.wikipedia.org/wiki/Seismometer) and set off some mapping charges. By measuring how the ground waves propagate through the area they will be able to locate any large caverns, or even areas with significantly different conduction of ground waves.
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I'm writing something in which the main character has become a vampire, or vampire-like entity, due to the influence of a Lovecraftian horror.
What are some things they, as a conscious person, may or may not experience due to a lack of a heartbeat that aren't immediately obvious and that aren't generally considered in fiction?
Some things I've already thought of are that, sweating, crying, blushing, sexual arousal, adrenaline rushes, and rash/irritation redness wouldn't be possible or noticeable. Also, apparent bruising would occur in the legs if the vampire stood or sat for long periods of time since the blood would settle due to gravity without the usual pressure. I'm also interested in how this might affect a person, psychologically. Assuming their personality was intact at the moment of transformation, how might the halting of lesser-known chemical processes (e.g. I know less dopamine means depression and impaired learning) affect this person mentally?
Basically, the horror's influence helps animate the character's body through a mixture of spacetime manipulation and psychokinesis in just enough ways for them to be a thinking, intelligent predator capable of harvesting blood through the desire to consume it. They also appear largely human and don't exhibit obvious signs of generalized hypoxia, like cyanosis. Though, their skin is a little paler than before and they're a bit cold to the touch. The character is still capable of logical thinking and, consequently, emotions, but I imagine their emotions and some thought-influenced bodily processes might be dulled or unbalanced due to the consequences of a nonexistent heartbeat. Thanks in advance, I hope you guys have some really obscure and interesting biology facts to lay down.
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It's a really complex question, I'll try to elaborate some thoughts disregarding a lot of biological stuff and coating them with a lot of fantasy dust.
Firstly, let's establish that no endocrine signaling would occur, as there's no "bloodway" for it to flow. Meaning that no long distance hormones should work on said scenario. That leaves us to paracrine and neurocrine signalling.
**Paracrine**
Paracrine signalling occurs on cell to cell level. For example, when there's an cut in the skin, the injured cells signal nearby tissue to start hemostasis and some degree of cellular repairing. For a full repair of damaged tissue, the body needs reinforcements from afar, which wouldn't happen. An interesting part of that is the cytokines, inflammatory molecules that are also released locally that can increase pain and inflammatory reactions. So, with some suspension of disbelief, any injury your character suffers wouldn't fully heal, there would just be an inflammatory tissue formed and never ending pain to a already tormented being.
**Neurocrine**
And how can it feel pain? Well, neurocrine signalling is also a cell to cell communication, but it's specific to neurons and their synapses. Pain would be preserved.
As for emotions, there are endocrine hormones and pathways responsible for regulating it, but let's not go that far into it as it would ruin any possibility for an interesting character. Let's say feelings are produced only at the brain and it's not affect by the lack of blood flow. Given that, body reactions to emotion would still be compromised. He would be afraid, he can recognize logically that he is afraid but he wouldn't feel afraid. Kind hard to explain, but you get the rough idea and there's lot of room for expansion on the topic.
There's a immediate response in the brain when you're eating to signal that you will be full after you're finished. Still, hormones produced by the stomach and intestine are not going to show the brain that your character is satisfied and fed. This could be the cause of his never ending hunger and blood lust, also another way to torment him as I'm sure that Lovecraftian being is up to no good. That brief moment of feeding is the only glimpse of relief he feels, just to be set back to a starving condition minutes after.
**Other random cool stuff**
-As there's no way to wash down the CO2 and lactic acid from the muscles, he would feel cramps and pain any time he get more worked up and active. He would need long times of rest to let those substances diffuse through his body (maybe the hibernating in a coffin stuff that conventional vampires like to do could be explained by that).
-Insufficient heart flow on the living causes lower limbs edema, accumulation of liquids on lunger that could result on bubble like secretion coming from his mouth from time to time. There could be a similar condition on your character. I think that may be too grotesque, but who knows what you might like?
-Due to constant hypoxia on the brain, there would be times he gets confused, does irrational things or gets inexplicably violent. As the times goes he forgets a lot of people he knew, places he went and the concept of who he is due to micro ischemia of certain parts of the brain.
That's what I can think now, but you should research more on these topics if you will:
-Neurocrine, endocrine, paracrine and autocrine hormone signaling pathways.
-Cardiac Insufficiency/Cardiac failure.
-Effects of mild hypoxia and hypoglycemia on the brain.
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One doesn't normally notice the sound of their own heartbeat but it's always there, until it isn't, that would be really disturbing. There would be similar but different effects with bloodflow through the eye ceasing and the cessation of one's pulse as felt throughout the body, these are things we're usually not conscious of but would almost certainly notice in their absence.
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To the best of my knowledge, this person would experience a painful and obvious swelling of their feet as the blood would be pulled down by gravity. Without a method of circulating the blood, there really isn't any other place all that fluid could go. If blood is no longer a requirement for this individual to live, it might be a good idea for them to simply release this pressure by getting rid of the useless blood altogether.
If they wish to keep that blood, I'm guessing for sentimental reasons, investing in some compression socks/pants would be another solution. Otherwise there feet would change color and they would go up two shoe sizes.
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Human vision works on differences in the visual field from moment to moment. If your eyes are tracking something exactly, it will fade out of vision fast. (It's actually still possible to see stark contrasts very vaguely, but no color vision will survive.) Biological processes like breathing and heartbeat help move the eyes enough under most conditions. Remove those, and the world can just vanish from vision if our vampire relaxes in a supported position.
In my limited experience, the lack of vision isn't immediately obvious, but moving the eyes to restore vision can be a little surprising.
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### The same as a regular human with an artificial heart
You have a basic problem that blood flow is essential for every part of the body to operate. It's certainly possible to micromanage the conditions to let parts of the body survive without blood flow (that's how we manage transplants, after all), but it's hard to do and it isn't a long-term solution. Any entity trying to do this is going to have quite some trouble making this work.
So why not take advantage of the body that's already there? If we have some telekinesis in play, why not simply use your telekinesis to pull blood from the heart's veins and push it back down the heart's arteries? You already know where to do it, all the pipework is already in place, and the body really doesn't care too much what pushed the blood so long as there's pressure there.
And this is pretty much what happens surgically. [Artificial hearts](https://en.wikipedia.org/wiki/Artificial_heart) have been around for a while, in various incarnations. Some designs of pump use continuous flow, which naturally means that the patient has no pulse. Hearts that "beat" are more reliable (spinning parts tend to wear, plus the impellers can damage blood cells), but other types have certainly been (and continue to be) used.
Sadly for your horror concept, this doesn't have any side-effects of turning the recipient into a ravenous monster. However it does have the distinct advantage of being totally plausible and logical (allowing for the existence of telekinesis, of course).
Of course there could be plenty of other reasons for the recipient to become blood-thirsty. If you allow for telekinesis, there could be other forms of psi powers such as mind control. Or (the Charles Stross PHANG version) the beasties driving your new powers may need blood, and may be perfectly happy to consume *you* if you don't find someone else's blood to offer them.
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# It depends on the design, but I'm going with a transdimensional circulatory system.
The treatment described is truly a redesign of the entire body at a microscopic level. Every effect ultimately reflects a design choice, not a biological imperative.
* The brain continues to function. Is it receiving glucose? Is it producing carbon dioxide? Without internal respiration (transfer of CO2 to capillaries), where does the CO2 go?
* The muscles continue to function. For aerobic exercise, this is the same as the brain. But to abruptly lift a heavy weight, we rely on the muscle's store of energy and then a transfer of lactic acid via blood to the liver for subsequent processing. Is the vampire able to sprint and lift heavy weights?
* The endocrine system continues to function. At least, the vampire doesn't seem to have hypothyroidism, Addison's disease, rickets, and more all at the same time. Someone seems to be making a hormone by hormone decision about what keeps working.
* The bones continue to function. Perhaps bone remodelling, which happens around small blood vessels that can transfer calcium to or from the blood to allow changes in local bone mass, is still going on somehow.
* The urinary system seems to be duplicated somehow. At least, if the muscles still use creatine phosphate for energy storage (which they should to avoid being much weaker in anaerobic situations), then somehow the creatinine waste product is steadily being removed from the body to avoid a build-up. End-stage renal failure is not a good thing, and without blood to filter, the kidneys would appear incapable of functioning.
* The lymphatic system is still refreshing the tissues of the body, despite apparently having nowhere for the thoracic duct to deliver lymph to. Also, the lack of CSF circulation from and to the blood is normally associated with severe headaches if there is a CSF leak after a spinal tap procedure; here something else happens. Don't forget the need for a regulated pressure in the eye as well, working via a fairly similar method, ciliary processes to venous sinuses (scleral rather than dural, but the idea is the same).
The most obvious way to replicate blood using a "spacetime" tech is if there is a bridge of cytoplasm from each cell to a nutrient pump site outside our dimension, or simply a ECMO (extracorporeal membrane oxygen) device which is *really, really* extracorporeal, perhaps linking the beginning and end of each capillary bed via another dimension to the circulatory system of some other, transhuman, creature. I think I'd go with the latter option; it is relatively non-invasive apart from all the scattered portals in the body, and it can be supposed that a being much more intelligent than we are is able to open new portals wherever its intervention has created unresolved problems.
In the context of an artificial and Lovecraftian manipulation this is disturbing, yet we might bear in mind that, through the sequence of parallel universes in the cosmos, at least within the realm of our consciousness, we may not be so different from this being, save from having our measurable physiology limited to the conventional four dimensions.
[Answer]
Reaally steady pulse.
No need for deodorant.
When cut, your blood won't make a jet in the air, only leaks.
Without good flow, your body may be hot in some places and cold in other. The heat isn't redistributed.
Insects will pursue you ralentlessly as a cadaver in ripe state for flys laying some eggs.
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[Question]
[
As part of a series of questions about a hard sci-fi universe (for more answered questions about it, please check [this](https://worldbuilding.stackexchange.com/questions/112853/railgun-launched-nuclear-warhead "Pew packing a boom") and [this](https://worldbuilding.stackexchange.com/questions/112971/multi-staged-relativistic-projectile-usable-in-hard-sci-fi-space-combat "Boom packing a pew"))
The setting is the same:
>
> I'm making a world where sub-FTL interstellar travel is a thing, and
> so is interstellar war, but for the purpose of this question we'll
> assume the scale to be of a single system.
>
>
> Spaceships have evolved quite a bit since our current era, and they
> range in size from several meters (something like 2 times larger than
> your average air superiority fighter, having a space-worthy manned
> vessel can't get any smaller than this in my universe) to up to 20
> kilometers in the shape of a scaled-up space submarine.
>
>
> Weapons comes in varying shape and size (proportional to the ship that
> bear them) and can be split in 3 categories:
>
>
> * Missiles : Just your everyday payload carrying self propelled
> firestick, you could also call them torpedoes at this point, it
> doesn't really makes a difference as far a I know. They won't get
> bigger in size than an ICBM and the tech didn't evolve much aside from
> targeting and space-worthiness.
> * Lasers: They are mainly used as a countermeasure and/or to mess with
> enemy targeting systems at close range (and occasionally to blind the
> enemy commander trough the window as a prank).
> * Railguns: This is where R&D was the most successful, since those guns
> can get pretty big (remember the 20km ships?) and the biggest
> projectile to date is a whopping 100m long and can travel at 30Km/s.
> Picture throwing Saturn V at the enemy vessel). Please note that for
> smaller projectiles the speed can get up to 150km/s, but that is a
> very specialized gun and the average is less that 100km/s for a decent
> gun.
>
>
> Concerning energy requirements, capacitors went a long way and are now
> extremely efficient, as well as cooling, even in space (firing a
> railgun more than once won't melt it for the first couple consecutive
> shots) and fusion is the go-to mean of energy production across the
> civilization. Dyson sphere project started in some systems, and the
> question of the access to the host star sparked the wars in the
> systems.
>
>
>
**Armor**
Ships in my universe are armored, but since I want to maintain a decent amount of consistency, I can't just strap a 5m layer of whatever armor on the hull and call it a day. Even worse, Unobtainium seem to be... unobtainable. I then went for some whipple shields and reactive armor and the likes, to get decent protections with limited wheight. The thing is, all of this works wonderfully against space rocks, but when some weapons (say, a missile) have counter measures to your counter measures, things start to get tricky. So what I need is a shield, separate from the hull, and far enough to make any missile useless, or at the very least less deadly.
**Shield**
So far, the shield I came up with is based on generating local magnetic fields to have some iron dust orbit the ship at high speed. This would give me a hollow sphere of iron rotating a some speed (at least 3km/s at the equator of the thing) with a density of matter of at least 1kg/m3. the weak point at the poles of the sphere would be fixed with a second sphere perpendicular to the first (and of slightly different radius of course).
Such a shield should be able to destroy incomming missiles even when undetected, and prevent any boarding of the ship by small assault vessels should they survive the fixed defences of the ship. Whith some luck it may even deflect a fast moving inert projectile (fired from, say, a *railgun*)
As of the size of the ship, i'll be going with the biggest (20km submarine shaped) in my universe, and energy requirement are moot (exept if this system requires the power input of a star).
Tech level is several centuries ahead of current tech, so extrapolating to the limit of physics is acceptable a long as the tech is plausible.
Now for the fun part: **Would this shield system be realistically possible?**
Bonus: If it's nonsense or simply impossible, what kind of current tech would make a good remplacement for this system that isn't an insult to reality?
[Answer]
**Point Defenses and Manuevering are better than "Force Fields"**
Lets assume 3 things:
1: Computers are faster and able to process larger amounts of data in that smaller time allotment.
2: A corresponding advancement in sensory technology has made sensors both very sensitive, very fast, and very long range.
3: Lasers have become much more powerful (in the megawatt ranges at-least)
A suitably powerful laser could burn through meters of steel per second, making such an emitter is actually within current tech ability, its just powering the damned thing isn't economical enough to try. So a rail-gun projectile or missile is coming at your ship, the sensors detect it, the computer calculates its vector and determines that it will impact the ship, then it fires one of the point defense pulse-lasers at it and vaporizes part of it, which either causes the missile to explode, or vaporizes enough of the rail-gun projectile to nudge it juuuuuust a wee bit off course. Maybe a firing Solution isn't needed. Maybe the ship just needs to alter its acceleration by .5% to avoid the projectile. This is space and the distances involved are so immense dodging a rail gun projectile is simply a matter of not moving at the same velocity when it arrives as when it was fired. Even just a tiny nudge can equate to kilometer wide margins of error for the gunner trying to hit the target. In space combat we are talking about battles taking place at thousands or even millions of kilometers. Ships may even be firing from one orbit into another. This means that no matter how fast projectiles are there will always be ample time to detect them and either evade or open fire. This is why lasers were practically blessed by our universe's physics to be used in space combat since they move at the speed of light and no matter what your enemy is throwing at you unless its another laser you will always be faster.
Another great way to use lasers is to blind enemy sensors, even at ranges where the beam is too diffused to cause outright damage to the enemy it can still damage sensitive electronics and fine equipment, which sensors tend to mostly be comprised of. At extreme ranges you could force the enemy to shutter or shelter their sensor arrays until they are within your engagement distance.
**The Problem With Your Shield**
The issue your shield is going to have is that your own cloud of iron dust is going to mess with your sensors. The more sensitive detection equipment is the easier it is to make a mistake. You will essentially be blinding your long range sensors (radar, ladar, thermal, IR, UV, etc etc). Like I mentioned earlier the biggest advantage in space combat you can have is long range detection. In space combat the defender will always have the advantage over the attacker since they can be detected from millions of kilometers out and anything they are doing cannot really be hidden. Giving up that advantage just to maybe stop a few missiles that your long range lasers could have handled half a million klicks out just doesn't make sense. Accurate powerful weapons with standoff distance, more powerful and sensitive sensors, and targeting computers with faster and more accurate reaction time are the closest thing to a shield that a vessel is going to have in our current understanding of physics.
[Answer]
>
> Would this shield system be realistically possible?
>
>
>
Physically, no. You have two problems to begin with:
* you cannot accelerate iron particles using a central magnetic field. You would need *charged* particles and, even then, you can't control them with a static or variable field.
* you cannot have two hollow spheres one inside the other with different planes of rotation, because the field that controls the farther one would inevitably disrupt the other.
Then again, you have a further problem - the ship would need to *move*. This would require a much greater degree of control, as any collision might send particles against the ship.
And, of course, you could never *shoot* from inside the shells - your missiles or laser beams would collide with your own shield.
Finally, the **mass** of the shield would make things awkward - one kg per m3 may seem little, but the volume of a spherical shell surrounding a starship has a lot of m3.
But in space, without air resistance, you could easily prepare a "shield" with very thin, reflective film at some distance from the ship, kept in place with very thin whiskers. Inside that volume you could also be able to manipulate electric fields and transmissions, and (e.g.) make it seem that the ship is in a slightly different position or orientation. Of course, as soon as you fire the engines, the ruse will be uncovered. The film can reflect lasers and perhaps disrupt some kind of projectiles ("[Whipple shield](https://en.wikipedia.org/wiki/Whipple_shield)").
[Answer]
**shields**
Other answers already list some problems with your proposed shield of iron dust. An IMO better design would be to have the shield consist of small active projectiles. The projectiles can generate their own magnetic field to interact with the one the ship is generating and those of other projectiles. With this active control each projectile can have its own unique orbit and change that orbit, you're not stuck to a sphere of dust rotating all in the same direction.
All this would require a lot of computer power by todays standards, but nothing unrealistic for a space faring future.
The magnetic fields would change in strength and orientation semi-randomly, but as each projectile knows how the field is going to change it can adjust its own field in accordance. This also ensures enemy weapons cannot disturb the shield too much, as they don't know how the field is changing and so they cannot counter it in a predictable way, though they could still try to disturb the shield with their own random magnetic field.
Such an active shield also gives better protection against (detected) weapons, as a large number of shield projectiles can arrange to intercept the incoming weapon. Of course the ship has an automated factory to produce replacement shield projectiles, and you might have a mix of different kinds of projectiles that could vary depending on the expected environment.
There is still the question of how effective this shield is. An incoming weapon will collide with the shield projectiles, and given the speeds all the participants will break apart and partially vaporise. You will then have a cloud of vaporised metal and scrap hitting the ship at many km/s. If the shield is far enough out from the main ship the cloud will have expanded a bit, so it will be less damaging than a single mass of an intact missile hitting your ship. Enough whipple shield armor might then stop the debris, but I wouldn't be able to say how much you need to realistically stop it. But at least the debris cloud won't be deploying countermeasures, so the ship would have a chance.
**projectiles and propulsion**
The part I don't buy in the description of your world is that missiles aren't much better than what we have today. If these people are traveling interstellar distances they probably have ships that can reach much higher speeds than what we have today, and therefore much more effective drive systems. The speeds of several dozen km/s you mention for big railgun projectiles is probably already within reach of current rocket tech. Just launching into orbit already requires a delta-V of ~10 km/s. If whatever drive technology they have is applied to missiles, those would also be reaching speeds similar to the railgun projectiles, and be equally effective, except you don't need a railgun.
Of course, you may want to combine both systems. A railgun-like magnetic accelerator launches a missile to a high speed, and then the missiles drives fire to speed it up even more and provide some maneuverability etc. Making the missile survive the high-g acceleration doesn't sound like a big problem, the US was already using [radar-rangefinder equipped artillery shells in WWII that had to withstand 20000 g](https://en.wikipedia.org/wiki/Proximity_fuze).
[Answer]
**Use your magnetic fields by themselves.**
>
> So far, the shield I came up with is based on generating localmake magnetic fields this strong, set them up and let them run with nothing in
> magnetic fields to have some iron dust orbit the ship at high speed.
>
>
>
This is a great idea except for the iron dust part. If you have the ability to them. You will not have to worry about changing direction of the ship with the inertia of your iron cloud, or that the iron cloud is too thin, or that you have run out of iron. Your magnetic fields can stop incoming ordinance in the manner of an [**eddy current brake**](https://en.wikipedia.org/wiki/Eddy_current_brake)
>
> A conductive surface moving past a stationary magnet will have
> circular electric currents called eddy currents induced in it by the
> magnetic field, as described by Faraday's law of induction. By Lenz's
> law, the circulating currents will create their own magnetic field
> which opposes the field of the magnet. Thus the moving conductor will
> experience a drag force from the magnet that opposes its motion,
> proportional to its velocity. The kinetic energy of the moving object
> is dissipated as heat generated by the current flowing through the
> electrical resistance of the conductor.
>
>
>
A high velocity conductor entering the magnetic field will generate enormous eddy currents within itself and convert its kinetic energy into heat (of itself). Incoming missiles will heat up to glowing hot, which will be hard on their components.
Also, your magnetic field will be a fine detector. Something entering one of your fields will be easily detected by the perturbation it causes, and all of your field generating power can be swung to bear to the relevant field - this would take a nanosecond.
Someone posted this proposition (stop bullets with eddy currents) to the physics stack but those fuddy duddies closed it. But not before there was a fine and math-rich answer posted.
<https://physics.stackexchange.com/questions/238332/can-we-stop-moving-bullets-by-eddy-currents>
---
I am thinking how cool the CGI of this would look. As opposed to bouncing off an invisible barrier, the projectiles would slow and also glow with heat as they slowed. Consider smoke - on earth smoke trails behind a smoking object because it is slowed by air resistance. In space there is no air resistance, and the smoke would not be slowed by the magnetic field. Smoke, vapor and molten droplets (the smaller the object the weaker the eddy current) would retain the momentum they had and would shoot forwards off the slowing, glowing hot projectile.
[Answer]
$1 \ kg/m^3$ is the same order of magnitude of the density of a gas at sea level.
If a flimsy shell fired from a rifle can pass through it, imagine what the effect will be on anything launched by what you devised in your previous questions: almost null.
If you had a stopping power equivalent to the launching power of the enemy's rail gun (meaning you can deliver the same acceleration given by the rail gun), you would need about 18 km to stop the shell.
IMHO your best options are (even better if combined):
* evasive maneuvers: as you pointed out, firing those shots won't be stealth. Take advantage of this and move out of the trajectory as fast as you can.
* kinetic hit: fire a counter shot or a series of shots aiming at or around the projectile. The impact energy will severely damage the device before it hits you.
[Answer]
The shield idea is interesting, a bit like ablative armor, but its greatest limitation is the resource: iron. Unless you're hauling around a bazillion metric tons of it, you'll quickly run out of it. In fact, you could depend on your enemies developing weapons designed to vaporaize vast amounts of it just to clear it out of the way.
As for current-tech solutions, there aren't any. We don't have shielding today, nor is any technology remotely close to providing one.
However, you're not on the wrong track. Let's use some handwaving and suggest that you have a *nuclear force* shield, one that has the strength of the nuclear bonds between atomic particles, and that shield is rotating around the ship. It's purpose is to capture and redirect objects away from the ship (not unlike a street sweeper). I don't think this has been done before, and no mass-oriented object would be capable of penetrating it unless the energy of that object exceeded the energy applied to the shield.
[Answer]
This shield system sounds *possible* (so the answer to your question, strictly speaking, is "yes",) but not very effective at all for its intended purpose. It would be relatively easy for a missile to counter - either by generating it's own local field to move the iron out of the way, or simply match velocity with it and bump its way through the relatively static pieces of iron.
You're much better off with a proverbial "shield," one that works basically the same way as our current missile shields: actively detect incoming threats and intercept them with either anti-missile missiles or point defense fire. This is a lot easier to do in space than on Earth too, because there is no atmosphere to attenuate lasers (or other beam weapons,) no horizon to limit your detection range, and no unrelated activity in your surroundings to potentially cause false positives.
[Answer]
Sounds like it would work to me. Get the dust moving fast enough and it should act like a shield.
Keep in mind, though, that it would act like a gyroscope, increasing the ship's inertia. If you are accelerating the dust to relativistic speeds, it might make it almost impossible to accelerate or change direction.
The dilemma for ship captains would be whether they try and Dodge, or turn up the shield and hope for the best.
[Answer]
Kinetic Water shields perhaps?
For some reason I can't find a reference to them anymore except a few vague ones [here.](https://books.google.nl/books?id=WAX3CwAAQBAJ&pg=PT378&lpg=PT378&dq=kinetic%20water%20shield&source=bl&ots=_aakNB6k46&sig=k9FYoV6urVqY0kfHncq6wgPospY&hl=nl&sa=X&ved=0ahUKEwiYrPjx8J7bAhUlDZoKHf--BosQ6AEIbTAM#v=onepage&q=kinetic%20water%20shield&f=false)
But water shields, besides wonderful against things like plasma or radiation, could protect against kinetic impact. The faster a bullet enters water the more pressure it creates for itself causing it to crush itself and scatter kind of like a Whipple shield. I'm not sure how it will react to high-velocity impacts, but I can imagine that the amount of energy required to vaporize the water will absorb much of the energy and the additional "explosion" of sudden vaporization might work against shaped-charges that might be inside the missiles. As a bonus, if you blow a hole in a water shield the remaining water will move in to fill it up, forcing the enemy to chew through lots of your "armor" across you entire ship before they start dealing the real damage.
I still can't find a good reference, but I believed they wanted to use some kind of electrically powered hydroloving field that made the water stick together more and remain on top of a surface, even if you are under gravity (I originally read something about America looking into those supportive-frame Mechs and using a water-shield to allow the soldier to walk through bullethails with barely a scratch).
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[Question]
[
In an alien society, humans, humanoids, bipeds, and quadrupeds mingle on a daily basis. Assuming all the humans and humanoids wear clothes as we are accustomed to them, what would be the quadruped response?
Obviously, one of the primary reasons for clothing is to conceal particular features of anatomy, but I'm having a *huge* amount of difficulty designing clothing for this purpose without getting results as laughable as this comic:
[](https://i.stack.imgur.com/6ln7x.jpg)
However, I'm also open to reasons quadrupeds might forgo clothes despite the practices of their humanoid neighbors.
[](https://i.stack.imgur.com/LJhwK.png)
[Answer]
Considering a *pair* of trousers referers to the fact that they were originally 2 seperate tubes, with a codpiece in the middle, then a quadraped is more likely to wear what looks like a 2 pairs of trousers front-and-back, with a blanket wrapped around their middle - as an outgrowth from a tube of fabric on each leg.
The "all four legs joined together" case as pictured is bad because of the bending in the middle when you move around - this would cause it to sag away from the body or pull tight and restrict movement, like wearing dungarees and bending over forwards or backwards. You would need a belt-strap in the centre going around your back.
(Of course, a bear is actually a more complicated case, since they can alternate between quadraped and biped movement - depending on how long they spend in each state they could dress "top-and-bottoms" like a crawling baby does. If you rank from quadraped to biped, you get something like "Horse » Bear » Orangatan » Human")
[Answer]
I think you are approaching your problem from the wrong angle.
Humans started using clothes not out of prude, to hide what (allegedly) should not be under the shining sun, but simply because we, as fur-less apes, lack any basic protection against weather, and the more we moved out of the savanna, the more we need to get protection from cold and rain. Only afterwards the act of wearing clothes became so deeply carved into our mind to turn into prude.
If your animal are not fur-less there is no stringent reason for them to wear clothes. Also, human females are the only one to have permanent breasts: other mammals have them visible only during breastfeeding. And I hope you agree one doesn't need a bra if there are no breasts to support/conceal.
[Answer]
It's a question of the clothes being able to stay on, be comfortable, fit for purpose and suit the societal norms.
One major factor is the location and dexterity of manipulative digits on the being. They need to be able to put it on and off by themselves.
The next thing is what is expected by the alien society. If they don't wear clothes, they're not going to want to change that. Clothes could just consist of belts with pouches, jewelry to show status in society and protective garments.
In reality the design of clothes is based around the design of the creatures and their society.
[Answer]
Though I personally think it is ridiculous and borderline cruel in a few cases, we have to file this one under the "This Exists" file: [dog sweaters](https://www.google.com/search?q=dog%20sweaters&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiu-fCdrdraAhXDy4MKHbiwB4AQ_AUICygC&biw=2133&bih=1054). There is a whole industry around it with some insiders calling themselves "fashion designers." They've had literally decades to tweak and experiment with both form and function, so why not steal their ideas?
In the image search I link, it seems the majority are more like a cape, that covers around the chest but only over the back, not covering the "particular features of anatomy" you desire. But in between there seems to be a few that wrap around the haunches and between the hind quarters.
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[Question]
[
**Setup:**
We are in a alternate timeline where there is a [Counter-Earth](https://en.wikipedia.org/wiki/Counter-Earth) that always stays perfectly on the exact opposite side of the Sun from our Earth. It has about the same size and mass as our planet, but is lifeless. It doesn't have a moon.
Everything that happened on our planet historically goes down the same way, i.e. the effective point of departure from our timeline is the discovery of Counter-Earth.
**Question:**
Roughly in what year would scholars first start suspecting Counter-Earth exists? When would its existence be proven? What tools would be used to do so?
[Answer]
As soon as we started closely observing the sky.
<https://en.wikipedia.org/wiki/Counter-Earth#Scientific_analysis>
>
> The gravitational forces of the other planets on a Counter-Earth would make its orbit unstable. Venus has 82% of the mass of Earth and would come within 0.3 AU of the location of a Counter-Earth every 20 months, providing considerable gravitational pull that over the years would move its orbit into sight of observers on Earth.
>
>
>
EDIT: adding @a4android's excellent comment clarifying my answer
>
> What RonJohn is saying is that a Counter-Earth won't remain perfectly on the opposite side of the Sun. This will have happened, possibly, billion of years ago. The Counter-Earth would keep being seen as a star almost as bright as Venus & close to the Sun quite often. The ancients would know it was a planet.
>
>
>
[Answer]
Given your requirements that the counter-earth orbit entirely opposite the Earth and ignoring the factual difficulties involved with this orbital alignment, when would we have discovered (aka, "proved") that the counter-earth must exist?
**Answer: sometime between the years 1500 and 1600, the years of Copernicus, Galileo, and Kepler.**
That's when we developed the mathematics of orbital mechanics well enough that we could determine what was causing the orbital perturbations in the other planets.
Before this time, people would have created everything from messy stories to very complex astrolabes in the effort to rationalize the planetary movements they were seeing. They would have been whomping complex and would demonstrate time and time again that something wasn't properly understood.
Once orbital mathematics moved from infancy to reasonable maturity, one of those great astronomers would have published a treatise exclaiming, "there must be a planetary body directly opposite from ours!" And that's when history would diverge.
[Answer]
In a system of universal gravity obeying an inverse square law, such a planet will not exist, as is discussed in other questions. As such we must suppose that gravity behaves differently in this universe. In particular *I will assume that there are no gravitational consequences of this planet*. It causes no perturbations of Venus, and is in a stable "orbit" of the sun.
It could not be detected by Earth bound observers. I would be hidden by the sun for anyone on Earth. It could not be detected by its reflected light off Venus (too dim)
It would only be found by space probe, probably one of the Mariner series, or the Russian Venus probes in the 1960s. As they take an image of the stars, for navigation purposes the extra bright object would be very clear and very surprising.
[Answer]
As others have noted, the gravitational pull of other planets, notably Venus, would prevent this planet from always remaining exactly on the opposite side of the sun. I haven't done the calculations, so I'm not sure if it would deviate ENOUGH to actually be visible from our Earth.
But regardless, I suppose, for the sake of the question let's assume not. Counter-Earth is always behind the Sun or so close to the Sun that it is invisible.
Once people discovered gravity and starting figuring out orbital mechanics, they would figure out that there must be another planet of this mass and in this orbit. Neptune was discovered this was in 1846, and it's effects are much smaller and more difficult to observe than Counter-Earth's would be. So absolute latest is early 1800s. I would have said earliest is when Newton formulated theory of gravity, 1687. (I'm not sure on what basis others have said 1500s. Maybe they're making different assumptions or maybe they know something about the history of astronomy that I don't.) But I'd say that -- going by the assumption that it is never visible from Earth and we can only deduce its existence from gravitational effects -- it would have been discovered sometime in the 1700s.
As to what difference it makes to history ... hard to say. How would Earth history be different if Mars or Venus did not exist? This depends a lot on how "fragile" you think history is. Think of all those time travel stories. If someone went back in time and changed one little thing, would the effects quickly peter out, lost in the rounding errors, and history proceeds as before? Or would that one small change create larger and larger ripples until history was totally different?
In this case, if someone said, "Hey, I've proven that there is this Counter-Earth on the other side of the Sun", would people basically say, "Wow, how interesting", and go on with their lives as before? Or would it lead one person to spend a night standing on a hill staring at the sky, and while he's standing there he catches cold and dies, and he was the person who would have made some crucial scientific discovery, and so, etc. Or, would someone wonder how life on Counter-Earth might be the same or different from life on Earth, and this leads him to philosophize about why history happens the way it does, and he proposes some ground-breaking new theory that changes how we look at the world, etc.
You say this world is lifeless, so there would be no issue of people communicating with the (non-existent) inhabitants. So aside from the philosophical implications, and possible "butterfly effect" sort of incidental implications, there would be no direct effect until space travel was developed to the point where people could travel there.
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[Question]
[
Imagine Naga grenadiers. [Snake people](https://vignette.wikia.nocookie.net/mahabharata/images/1/14/Naga-astra-indian-mythology.jpg/revision/latest?cb=20150912185946), human from head to hips, with a snake's body instead of legs.
How would they throw grenades? Much as humans do. Except, as they're throwing the grenade, they lash their bodies forward, the same way a [snake strikes at a target](https://www.youtube.com/watch?v=3jJn7UHyR3Y).
The question is, would this allow them to throw the grenade further than a human could? Snakes can strike awfully fast with their little heads, but do they have more power than a human thrower?
---
In light of an interesting answer someone gave, I will propose an additional detail you may want to consider including in your answer: Do you feel Naga should throw grenades with their arms, or with their tails? This point is completely optional, but I thought it worth sharing.
[Answer]
I think they could definitely throw farther.
Combine the leverage gotten by the arm with the snake strike, and you have a heck of a throw. This would be on the order of magnitude difference between someone throwing a clay pigeon by hand or with a clay pigeon thrower.
>
> [https://images-na.ssl-images-amazon.com/images/I/51X4SE35exL.*SL1500*.jpg](https://images-na.ssl-images-amazon.com/images/I/51X4SE35exL._SL1500_.jpg)
>
>
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What happens here is that the longer the handle, the faster (and farther) the clay pigeon will be thrown. It takes more muscle, but to have a snake strike on a being as large as a Naga, you're going to have that muscle.
The trajectory of a propelled/thrown object, which is used to calculate distance, is very much dependent on the initial velocity of the object.
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> <https://en.wikipedia.org/wiki/Projectile_motion>
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The above link is the math, and the below link is the specific image on the above page that shows the correlation between initial velocity and distance, which considers air drag.
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> <https://en.wikipedia.org/wiki/Projectile_motion#/media/File:Mplwp_ballistic_trajectories_velocities.svg>
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As far as accuracy is concerned, the farther the distance you are trying to hit, the harder it is to hit. That goes for everything. Getting accurate simply means more practice. Shooting a rifle accurately is pretty simple, if you're aiming for a target 50 ft away in a building. Snipers have confirmed hits at over a mile in less than perfect conditions. The thing that snipers have is training, which the military is likely to give these Naga grenadiers.
When I went through Army Basic 20 years ago, we had to learn how to throw grenades, and we had to be fairly accurate about it under standard distances. It was just a 1 day training course, but we still had to do it as an standard practice. Someone who has a "job" of "grenadiers" would have to go through training to get that position, and training continues after getting that position.
The advent of grenade launchers pretty much makes long distance hand throwing not necessary. The max range of the M203 grenade launcher I carried for my Reserve unit is 400 meters. It has a minimum safe (combat) range of 31 meters.
According to the link below, the average soldier can throw a grenade at least 20 meters, and should throw it at least 35 meters to be safe. This is because the (standard US military) grenade has a casualty radius of 15 meters. If you don't get it out there a good distance, you're going to be a casualty of your own weapon.
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> <https://www.quora.com/How-far-can-the-average-soldier-throw-a-hand-grenade>
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So, knowing that a grenade launcher can hit something at a shorter distance than a soldier can throw it, that pretty much negates the need for a "super throwing" grenadier.
Of course, that depends on your tech level. If you don't have grenade launchers, then Naga grenadiers are what you're looking for to clear rooms/trenches/gun emplacements at a distance.
[Answer]
**Probably**
This really depends on how well your Naga can "hold to the ground." Let's take my late pet Iguana as an example.
My Iguana, Lurch, was the terror of the house... and he knew it! Cats and humans alike quickly learned to fear the tip of that boy's tail. When he grew irritated, the tail cocked back, you were given the "evil eye," and you had seconds to clear out before the tip of that tail exceeded the speed of light and hit you with the force of an Hiroshima atom bomb.
It hurt.
There's certainly enough leverage for throwing a grenade a long honking way... but do you have the foundation?
Lurch was holding onto shag carpet. Shag carpet is the bane of human existence. It's hard to clean, hard to keep looking nice (my parents once had some you actually had to rake. *Rake! I tell you.*) But, when it comes to holding on to let that tail off the leash... oh, yeah...
**A sling of any kind, be it a sling shot, a trebuchet, a bow-and-arrow, a spear, even a cannon, is only as good as the foundation it's pushing against. That's [Newton's third law](http://www.physicsclassroom.com/class/newtlaws/Lesson-4/Newton-s-Third-Law) for you, and it hurts as much as Lurch's tail did.**
What are your options?
* **Weight:** If the amount of Naga resting on the ground is a goodly amount more than the amount of Naga used to throw the grenade, then he's good to go. If you think about it, humans are standing on two feet. We may take a moment to brace, but in the heat of battle, what are the odds you're even thinking about that? The truth is, the weight of your arm is considerably less than the weight of the rest of you. If this is also true for the Naga, they're good.
* **Anchoring:** The naga have an advantage, they can loop their body around something, like a rock, a tree, an appropriate chunk of ground. In a pinch, they could hook around the Naga next to them. This added anchorage would also solve the problem.
I can envision Naga combat tactics manuals teaching the new grunts how to form clover-patterns on the ground to give them the base they need to a wailing-long throw. And once they learn it, they can do it. In the end, strength in the arm (or tail) is a minor part of throwing a grenade. It's the force-multiplying leverage of the length of the arm (or tail) that's the real winner. If the Naga's tail is markedly longer than the human arm, they'll out throw us every time.
*You'll note that I completely ignored your suggestion that the Naga would throw a grenade by striking forward, like a cobra or a rattler. Have you ever tried to throw a baseball that way? It's a horrible way to throw anything. It's a close-quarters action that's good with a sabre or knife (or fangs). I ignored it because it's the wrong way to do it.*
[Answer]
I don't think they'd make good grenadiers.
A human-sized or larger naga should have a lot of muscle mass in the snake side of the body. That should do for a strong lunge. But strong does not mean accurate.
A cobra strike is efficient to land a bite on a target. Throwing something on someone else that is far away is completely different.
Imagine that instead of a naga, you have a centaur. Now imagine that the centaur is trying to kick a grenade towards someone with their hind legs.
The centaur can reasonably land a kick on someone else quite easily with their hind legs. Doesn't mean they will be good grenadiers using the same limb.
This line of thought works for us too. Most humans have more muscle power in their legs than in their arms. We still use hands rather than feet to throw stuff at small targets. Think of that.
[Answer]
**No**
Humans are amazing at throwing. It could be considered a specie-unique skill we have. [This study](https://scholar.harvard.edu/ntroach/evolution-throwing) shows why we are so good at throwing.
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> We found that humans are able to throw with such velocity by storing elastic energy in their shoulders. This is accomplished by positioning the arm in such a way that the arm’s mass resists motions generated at the torso and shoulder and rotates backwards away from the target. This “cocking” of the arm stretches the tendons, ligaments, and muscles crossing the shoulder and stores elastic energy (like a slingshot). When this energy is then released, it powers the very rapid rotation of the upper arm, which is the fastest motion the human body produces – up to 9,000 degrees-per-second in professional pitchers! This rapid rotation also causes the elbow to quickly straighten and the projectile to be released at very high speeds.
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> We further found that three key anatomical changes that occurred during human evolution made this novel energy storage mechanism possible: expansion of the waist, lowering of the shoulders, and low humeral torsion. The expansion of the waist allows the torso to rotate independently from the hips. This torso rotation generates large forces needed to stretch the elastic tendons and ligaments in the shoulder. The lowering of the shoulder changes the orientation of many shoulder muscles, including the pectoralis major (the large chest muscle), which is crucial to storing energy. Finally, we found that low humeral torsion (the twisting of the upper arm bone) allows us to store more energy and thus, throw faster.
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Humans are **significantly** better at throwing. In fact, the throwing ability of pretty much any other animal is not even worth consideration in terms of threat levels.
Now, the above article has noted that pretty much all the force comes from rotation of the arm and upper body and the waist. Lashing forward is not a good throwing technique.
When you throw, you should also note that you use your legs a lot. You use your legs to start your rotation and to keep balance. A snake body would have some trouble rotation the hips and keeping an upper body balanced.
Note that in a lunge, the snake simply wants to move his head forward. However, if a naga tried that, he'd have to lunge with his whole body. This would simply result in him falling over in embarrassment and wasting a ton of energy.
[Answer]
I would just like to add, that many of these comments are racist and have no basis in facts.
We're good grenadiers and my grandmother could throw a javelin better than Leonidas in 300.⁷
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[Question]
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What is the maximum size a ship can become without negating the effects of waves to the point where seasickness is no longer a problem? The larger a ship becomes, the smaller the rocking effect waves have on it becomes. As a result, large ships tend to have a lesser effect on people inclined to seasickness.
So, the question is: **How large can a ship become before it becomes extremely unlikely for a person only moderately inclined to seasickness to become seasick, during sea state 4 water?** A good answer will address multiple types of ship (e.g., an ocean liner vs an aircraft carrier vs an oil tanker), and how the directions of waves will affect the seasickness of the passengers.
[Answer]
There's a huge variation in ships.
It's not JUST about size, **it's [about design](http://www.escape.com.au/holiday-ideas/cruises/aurora-expeditions-reveals-new-ship-with-cuttingedge-design-to-combat-seasickness/news-story/3bc00f28484b6a1c6d4bd4c43975922e)**...angles matter in a big way.
And so too does **movement through the water**. As long as the boat is moving forward, seasickness is actually less likely. It becomes more of an issue if the boat is not moving, and simply bobbing up and down. The direction that the boat is moving in relation TO the waves is also an issue.
You also have to take into account **stabilizers**. Most large passenger ships today [have them](https://en.wikipedia.org/wiki/Stabilizer_(ship)).
Then, you also have to take into account **WHERE on the ship you are**. Different parts of the ship will experience these things differently.
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> If you tend to get seasick, cabin location is really important. It's a question of engineering, really. The lower and more central you are in a ship, the less roll and sway you will feel. Even if you choose a balconied stateroom, choose the lowest level and the most midship one you can find. The higher decks and cabins at the very front (forward) or back (aft) of the ship will rock and roll the most.[SOURCE](https://www.cruisecritic.com/articles.cfm?ID=77)
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The average cruise ship has a tonnage of 110,000 and length of 952 feet.
First, let's define "moderately inclined" to seasickness and "not unusually rough water."
Let's say we've got a [World Meteorological Organization sea state code](https://en.wikipedia.org/wiki/Sea_state) of 3. That would be 1 ft 8 in. to 4 ft 1 in. So 4-foot waves would not be felt on a ship this large. All of the other factors have to be taken into account, but... 4-foot waves are NOTHING to a boat this large. In my experience, 7 footers aren't much of a problem most of the time either. When it gets to 10-15 ft, you'll feel it, but again, this really depends on a) if the ship is moving and how it's moving in relation to the waves b) where you are on the ship and c) stabilizers (in some cases the stabilizers made it more of a slow roll, which can actually make things worse in some parts of the ship).
I would say that I am moderately inclined myself, but this not only depends on all those factors, but also what and how much I have eaten, and how hydrated I am to begin with (something that should be taken care of days before).
So the answer is **It depends on a whole host of factors, and how you define moderately inclined, and what "not unusually rough water" means EXACTLY. There is NO MAX size for this.**
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> “There’s no way to prevent motion sickness 100 percent,” says Dr. Art Diskin, Royal Caribbean Cruises Ltd. Global Chief Medical Officer. [SOURCE](http://www.royalcaribbean.com/connect/the-truth-about-seasickness/)
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[Answer]
I would say that you can get seasick on any size ship. However, the bigger the ship, the bigger the waves have to be.
I can speak from the personal experience of traveling across the Atlantic on a 650-foot ocean liner as a teenager ([this one](https://en.wikipedia.org/wiki/RMS_Empress_of_Canada_(1960))). On the first day out, we encountered some rough water. Maybe 30-foot waves, hitting at about a 45-degree angle on the bow. The ship would rear up, leaning to port, and then flip over to lean to starboard and plunge downhill. It felt like going on a roller coaster I couldn't get off of. Eight of my family of nine got seasick (my dad was in the Navy and had no trouble at all).
I was walking down a hall, wondering when it would end when I heard the sound of water crashing. I went to investigate and found the swimming pool. A four-foot wave was running from one end of the pool to the other, smashing against the end of the pool, and then another one. I got in, and the seasickness was immediately gone.
So, if you're ever on a cruise and you get seasick, get in the pool. The ship will move around you.
[Answer]
The size of the vessel has less effect on the amount of motion experienced by passengers than the orientation of waves versus the direction of travel of the vessel. Thus a relatively small vessel encountering a large swell head-on can (and from personal experience does) feel far more stable than a large ferry being hit by a very small swell at a 45 degree angle to the prow. Being hit "abeam" AKA either directly from Port or Starboard tends to be the worst.
I'm reasonably prone to motion sickness and one of the worst experiences I've had with seasickness came from a tiny swell (less than a metres) hitting a car ferry abeam on a fine day. The worst day I've travelled on was on the same ferry in a storm so bad they closed the ferry crossing behind us (and the road behind the bus the next morning too) but we were travelling straight into it and were able to sleep through the trip.
Given those two experiences I'm inclined to believe that there is no size limit to a ship built in the long linear tradition that would remove the influence of swells coming in abeam. As for waves hit head-on, they can be unnoticeable in surprisingly relatively small vessels.
[Answer]
It's simply not possible to come up with a figure.
Between the differences in ship design - hull shape will affect this, but so will stability measures (such as fins and anti-roll tanks) - the way that the vessel is being used (is it stationary, is it moving parallel or perpendicular to the waves) and how heavily is it loaded there are already too many things to calculate.
Add into that the question of how much movement is needed to become seasick - my sister-in-law once became motion sick in a branch of Ikea - and you have no chance.
There is generally a correlation between ship size and a decrease in motion sickness, but that's about as far as you can get.
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[Question]
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See, I'm a low-g cargo shipper by trade. We get all sorts of containers in all kinds of shapes that we need to fasten to the deck plating, and to do that we use magnetic clamps.
Now, these clamps are all manner of strong. Like, stupid strong. My engineer tried to explain it to me, something about super magnetic rare earth, I dunno. When the power is on we can just deactivate the clamps, but when the clamps lose power they snap back to the deck like a bear trap to a grizzly. Makes sense, I guess, cos the last thing you need when the reactor cuts out midway to Europa is two ton metal boxes floating about the place.
Thing I can't figure is how they work!
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The question here is what effect or mechanism could be used to negate the effect of a very powerful solid state magnet if and only if power is available. Simple designs are preferable.
[Answer]
These already exist, and are called [Magnetic Bases](https://en.m.wikipedia.org/wiki/Magnetic_base). They are used for attaching tools onto workshop equipment:
[](https://i.stack.imgur.com/bTgGY.png)
They attach very solidly (Nearly impossible to remove by hand), and I think that if they were upscaled they could indeed work for holding containers onto spacecraft. They can clamp any piece of ferrous metal.
As they currently are designed, they do not require any power to hold in either the on or the off position, and the force required to toggle them is tiny compared to the force they can exert.
If you want them to automatically engage when power is not applied, then the addition of a rotary spring to auto-rotate the magnet into the "on" position should allow this.
[Answer]
Simple:
One bar magnet on the cargo, fixed, one in the floor, that can rotate freely. Without power, the two align north to south, south to north, and hold the cargo in place.
There is a motor connected to the floor magnet with a clutch that is closed by a small electromagnet. The motor can turn the floor magnet until the net force is zero. There is still a large torque on the magnet then, so in a power failure it will snap back immediately.
During loading, the floor magnets are monitored by a feedback loop that always turns them into the "neutral" position with respect to any passing cargo magnet fixture. The magnet on the cargo can move vertically slightly and is kept fixed in the "away" position by a small spring. That way a power failure during loading is less dangerous for the workers feet, and you don't get large torques on the cargo.
[Answer]
Distance.
Each clamp is its own independent system, essentially a very powerful permanent magnets sandwiched in the middle of two screw driven scissor lift assemblies. Each screw is driven by a high speed electric motor, which also has an attached battery that always maintains enough charge to lower the jack to the floor.
Operation is simple: plug power into the jack motors and raise them to their full extent; this will pull the magnet away from whatever surface it was attached to. Move the clamp to the desired container and wind down one of the jacks, bringing the magnet into close proximity (or if the clamps are made right direct contact) with a magnet. Move the container to its desired location and lower the second jack, bringing the magnet into contact with the deck.
To release cargo just extend the first set of jacks again. There will still be a little magnetic pull, but due to the distance from the magnet the cargo should now be free.
In case of external power loss each clamp defaults to both jacks retracted, and the slight magnetic pull of the clamps will ensure the cargo attaches securely to the floor unless the ship is under thrust, in which case why the hell is the cargo not secure already?
Pros: easy to use and repair/replace, works on any ferrous item or surface, can be used to clamp containers together, can be manually operated if required, keeps enough distance between container and floor that crush injuries can be avoided.
Cons: 'snaps' to deck comparatively slowly, takes up space in cargo hold with an air gap, reduces surface area on the deck (and thus frictional forces), won't return to the locked position in case of catastrophic electrical event (i.e. Component failure or EMP)
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[Question]
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I'm writing my first sci-fi novella and I'm looking for a bit of guidance from some scientifically literate people. My main premise is that an alien space ship similar to the death star enters Earth's orbit at a low orbit point. Its gravity causes earthquakes, tsunamis, meteor showers and all that fun stuff. My only problem is that I'm not sure how my characters are going to destroy the ship in a way that is scientifically plausible. I have a few ideas so far;
They somehow launch it into the moon, destroying it.
They somehow use gravitational slingshot method to launch it around the moon, Venus and Mercury and into the sun, destroying it.
They somehow pull the ship towards earth into the Roche limit, causing Earth's gravity to tear the ship apart, destroying it.
The problem is that, from my understanding, these methods would either complete destroy earth as well, or they're just scientifically implausible. I'm a bit of a science nerd, but I won't pretend to understand enough astrophysics to finish this story without some help and further research. Obviously, it doesn't need to be completely scientifically accurate, but I'd like to avoid any embarrassingly obvious errors. Any help would be GREATLY appreciated! (go easy on me, it's my first attempt at writing a book!) Thank you in advance!
[Answer]
You want to destroy a Death Star sized spaceship in low orbit around the Earth! Hold it right there! This proposition needs rethinking.
OK, firstly, a spaceship of this size must be massive if its gravity is interfering with the Earth. So its gravity will have some effect. However, it seems doubtful if the vessel's gravity could go this far. "My main premise is that an alien space ship similar to the death star enters Earth's orbit at a low orbit point. Its gravity causes earthquakes, tsunamis, meteor showers and all that fun stuff."
The tides would be messed up big time. Possibly, earthquakes will be triggered by a new set of earth tides generated by the vessel as it passes overhead of faults and seismic zones. While, tsunamis will follow deep sea seismic events, it not probable these were be happening too frequently. Additional meteor showers are unlikely.
What you have is a gigantic piece of alien technology, admittedly with a mind-bogglingly large mass, in low orbit. This a fabulous asset! Firstly, it is made of processed and refined materials — metals, plastics, ceramics, materials unknown to technology, chemicals and, possibly, exotic timbers. Forget about asteroid mining! This is a gold mine of materials that can start humanity on the road to becoming a spacefaring species.
The giant spaceship must full of alien technology. If you are able to destroy without its passengers and crew popping out armed to their back teeth with laser-guns, then you are free to rummage through its technological golden goodies and kick start several technological revolutions.
Oh! You still want to stop all the earthquakes and tsunamis. That's understandable, under the circumstances. There's no need to destroy the death star sized spaceship. Just send a mission of scientists, engineers, and astronauts to go on board and locate the vessel's control systems. Go for a gentle restart of its propulsion system and move it into a higher, safer orbit around the Earth. Somewhere it will still be readily accessible to new tech hungry humans. There's no need to destroy it. The spaceship is more valuable intact and whole.
NOTE:
This answer predicated on the assumption that if the objective, as stated by the OP, to destroy the gigantic spaceship, then there are no aliens on board to resist attacking it. On the other hand, if there aliens on board and they are prepared to defend their territory to the last drop of our blood, then the situation becomes much more fraught. Time for some two-fisted action to save the day!
[Answer]
An alien spaceship the size of the Death Star is going to be largely empty space, if the movies are any indication, so even an object the size of the Earth's Moon isn't going to be anywhere near as massive. On that scale you should actually think of it more as a balloon than a planet. So if there are earthquakes, tidal events and tsunamis, it is because the Aliens are doing this deliberately, not simply because the spaceship is in orbit.
If the ship is crewed with Aliens with hostile intent, then in any realistic scenario we are totally SOL, since we would be dealing with technologies centuries or millennia in advance of our own. Launching nuclear tipped missiles at the object, or even building a massive ground based laser (and launching swarms of "fighting mirrors" to redirect the beam) is more likely to annoy them than do any significant damage, assuming they simply don't shoot down any incoming rockets or rocket launches first.
[](https://i.stack.imgur.com/ISiJB.jpg)
*Fighting Mirrors*
Other current warfare ideas are out as well. Hacking an alien computer system would require detailed knowledge of the hardware and software being used, and our laughable attempts at Malware wold be easily blocked by whatever firewall and antivirus systems they have. Biological attacks are even more unlikely (sorry, H.G. Wells) because disease organisms are highly tailored and specific to the organism being targeted. Trees don't catch colds, for example, and an Alien species would be far stranger than that.
What would really make this question more answerable is to provide some context. Why is this in orbit around Earth in the first place? What are the objectives of the Aliens? For that matter, what sorts of technologies do they use? How many of them are there? (A hollow, moon sized spacecraft could theoretically hold *trillions* of beings, depending on how tightly you can house them and what their material requirements actually are).
As a wild handwave, you could create a sort of nuclear "shotgun" on Earth to fire on the spaceship as it passes overhead, based on the late 1950 era "Pascal A" test shots. During the tests, one of the huge steel caps covering the shaft was blown off by the nuclear device at the bottom, and it was estimated it was launched into space at 6X escape velocity. Realistically, it was probably destroyed by aerodynamic heating and forces on the cap as it flew through the atmosphere, and vanished in a shower of molten iron droplets.
Imagine a silo filed with water. A small nuclear device is submerged in the bottom, and the silo "cap" is actually made of solid steel, perhaps with an ablative coating on the surface. The nuclear device is detonated, turning the water into plasma and propelling the cap at very high velocity into space. The water plasma provides much more efficient coupling of the energy from the nuclear device to the projectile, and a large field of them would pelt the object with thousands of massive slugs moving at 6X or more escape velocity, plus whatever velocity the object is moving at in orbit.
[](https://i.stack.imgur.com/eSKDU.jpg)
*Surprise!*
This has the primary advantage of being relatively quick and cheap, built on the ground so the odds of being detected are much lower than launching fighting platforms or weapons into orbit, and there is really nothing to spoof or jam, these are simply unguided steel slugs moving at incredible velocity (@ Mach 150 if they are moving at 6X escape velocity), and deliver their energy to the target by straight kinetic impact. A Deathstar sized target is going to be hard to miss.
Of course, you will create a radioactive wasteland where the "shotgun" was built, and assuming you have "killed" the death star, it is still in orbit (although sending salvage teams aboard will have incredible benefits, as a4android suggested in their answer.
[Answer]
You don't say *why* your protagonists need to destroy this vessel, so I'm going to go out on a limb here and suggest that as bad as the tidal effects of this large vessel are, it's actually the Evil Aliens (TM) who own this ship that are the real problem. If so, perhaps you need simply disrupt the ship's power plant to destroy the ship. Let me elaborate:
Dr. Rice of the University of Edignburgh (<http://www.roe.ac.uk/~wkmr/Teaching/Astronomy1G/Lecture3_6_slides.pdf>, among others) indicates that a black hole could be the most efficient way to produce power. Depending on the kind of black hole, matter-to-energy efficiency may be anywhere from 14% to 40%. For comparison, folks at the Physics StackExchange (<https://physics.stackexchange.com/questions/72926/in-nuclear-fusion-reaction-what-is-the-percentage-of-mass-converted-to-energy>) estimate that a fusion bomb converts less than 0.4% of its mass to energy. This makes the black hold at least an order of magnitude more efficient, and possibly much more.
All that capability makes a managed black hole really useful as a power supply for interplanetary travel. When it arrives at earth, it's also going to contribute a lot of mass to the orbiting vessel, which is why it generates such strong tides.
It would also put a lot of stress on the alien starship -- *except*, these aliens also have invented artificial gravity. In addition to keeping everyone happy during the long voyage, their antigravity also helps flatten out spacetime in the ship's hull, keeping things stable. Our progagonist doesn't know this, and, in an effort to escape, s/he turns off the ship's gravity in an effort to make life difficult for her pursuers.
Oops.
There is a big flash as the ship collapses into the black hole and our hero(ine) has sacrificed his/her life to eliminate the alien threat. The Earth is saved.
Now all we have to do is figure out how to get that black hole out of LEO. NASA is not amused...
[Answer]
A Death Star (140 - 160 km diameter - Wikipedia, 120 km diameter Wookiepedia) is very large, yes. The moon (3474 km diameter) is much larger. The first thing we can do is look at the forces involved. How much force does the moon exert on the earth, and how much force this "Death Star" exerts on earth.
The moon is about 384,400 km from Earth and weighs about 7.34767309 \* 10^22 kg. The equation for force due to gravity is $F\_g = \frac{Gm\_1m\_2}{r^2}$ where $G$ is the gravitational constant $6.67408 \* 10^{-11} \frac{m^3}{kg\*s^2}$. Earth is about $5.972 \* 10^{24}$ kg. From this we can calculate the force on the Earth due to the moon. Plug in all the numbers and it spits out a force on Earth of $1.98 \* 10^{20}$ Newtons $\frac{kg\*m}{s^2}$. However, for a 1km block on the surface of earth (earth has a radius of 6371 km), the force is $3.43 \* 10^{-5}$ Newtons.
Now, instead of using the moon, lets use this Death Star. Low Earth Orbit is between 160 km and 2000 km in altitude. So let's take the happy medium and say that it's at 1000 km in altitude. Now the hard part. How massive is this Death Star? If we say this Death Star is like an aircraft carrier, we can say that the density of the aircraft carrier is about the density of the Death Star.
Wikipedia lists the Nimitz-Class aircraft carrier at 100,000 long tons. A long ton is about 1016 kg. So the aircraft carrier has a mass of about 101,600,000 kg, or $1.016 \* 10^8$ kg. Lets say the volume of the aircraft carrier can be approximated with a triangular prism. The only problem is that I don't know how tall the aircraft carrier is, so this is likely to be a order of magnitude approximation, because I'm going to approximate it using an equilateral triangle. A triangle is $A = \frac{1}{2}bh$ and a prism is $V = Bh$ (big B because the base in this case is an area). A Nimitz-Class aircraft carrier is 1100 ft long and 252 ft wide. That's around 334 meters by 77 meters. Since the triangle is equilateral, the height is $77 \* \sin(\frac{\pi}{3}) = 77 \* \frac{\sqrt{3}}{2} \approx 66.7$ meters. The area of the triangle is ~2567 m^2 and the volume of the prism ~857500 $m^3$. Now that we have mass and volume we can find density.
Density is mass divided by volume. So the density of the aircraft carrier is ${1.016\*10^8 \, kg \over 857500 \, m^3} = 118.5 \frac{kg}{m^3}$. Now we need to find the volume of the Death Star. The Death Star is a sphere, so the only parameter we need is the radius. We stated at the very beginning that the Death Star is about 140 km in diameter, so its radius is about 70 kilometers. The equation for the volume of a sphere is $V = \frac{4}{3}\pi r^3$, so plug in $r = 70$, and the volume of the Death Star is about $1437000 \, km^3$ or $1.437\*10^15 \, m^3$. Since the mass-density of an aircraft carrier is a good approximation for the mass density of the Death Star, then we can use the aircraft carrier density times the volume of the Death Star to get its mass.
The mass of the Death Star is $118.5 \frac{kg}{m^3} \* 1.437\*10^15 \, m^3 = 1.7\*10^17 \, kg$. That's pretty massive. Now let's say this Death Star is orbiting at 1000 km above earth's surface. The total force on the earth is $1.25\*10^18$ Newtons. That's about two orders of magnitude away from the force on earth from the moon. However the force on a 1 km block on the surface of the earth is $1.14\*10^{-5}$.
Huh. That's less than the moon. But we can move it closer. Let's move it in as close as we can, 160km (LEO lower bound) + 70km (radius of Death Star) = 230km. At that height, the force on a 1 km block on the surface of the earth is $2.15\*10^{-4}$. Now that's about an order of magnitude above the moon, which we already know causes tides. But is it enough to cause earthquakes?
There are [sites on the internet](http://news.nationalgeographic.com/news/2005/05/0523_050523_moonquake_2.html) that link the moon cycle and earthquakes. So I would say that it is indeed plausible that the Death Star could cause an earthquake simply by existing.
tldr: the death star could probably cause earthquakes.
Now, how to get rid of it. The easiest thing to do would be to lift its orbit until it no longer causes earthquakes. The easiest way to do that would be to infiltrate the spaceship and get it to put itself in a higher orbit. If there is intelligent life aboard this spaceship (very likely) then getting rid of it is going to be the least of your problems. The simple fact that they are causing earthquakes with little regard for the life on the planet is the first warning bell. They're not here to make friends. And they're here because they want something. They may want us as slaves (unlikely, robots are cheaper) or our minerals (star miners?). In any case, we need more information about who these people are and why they're here. So the first thing to do would be to try and establish contact. Examine the signals that the Death Star gives off. Then, build a plan appropriate to the information provided. If they request a representative of our race, that's the perfect way in. If their ship gives off no signals at all, that means that there is a vulnerability that we can try to take advantage of.
[Answer]
This answer assumes that:
The ship has no force field or any barrier whatsoever.
The ship has no life forms inside it.
The ship does not have any other weapons except the gravitational pull.
The ship features the Death Star of Star Wars.
The ships gravity is slightly lower than earth.
With these assumptions, we could also say that.
The ship has no bridge, or pilot seat.
The ship may be "floating", it wont have any engines that will make it fly, but some floating device.
The ship only moves forward.
There is really no way of destroying the ship, because its size would really cause destruction of Earth, but what they could do, is put rockets below the ship, which would "push" the object upward, or in any direction that may not cause Earth harm.Applying Newton's second law, The rockets should have the mass and acceleration needed to push the object upward. The rocket would also consider earths gravity pull while pushing the object upward.
[Answer]
Detonate two Tsar bomba type bombs simultaneously, on opposite points on its surface.
You'll dump some radiation on the earth, but nowhere near enough to do global harm.
[Answer]
How did it get there? If it was assembled elsewhere, presumably the same alien means of propulsion that caused it to come to its current location could be reversed, ideally with alien allies who are converted to the cause because life on Earth is so cute.
Alternately, you could land it in the Pacific Ocean where the proto-moon made a lot of room when it crashed there the last time several billion years ago, but unlike the proto-moon, you would do it very, very slowly.
But for the "Its gravity causes earthquakes, tsunamis, meteor showers and all that fun stuff." and an apparently unstable orbit, I would have favored some effort to short out its systems in place leaving it inert as a second moon, such as a huge electromagnetic pulse directed towards our best estimate of the location of the control systems. Still, if you could short out its electronics with an EMP and then nudge the inert death star further from Earth to the points where the tidal effects of its gravity on earth were reduced, that would be good.
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well assuming that these aliens are close enough in biology to humans that human viruses could effect them couldn't you just kill them off with some bubonic plague then somehow figure out how to move the ship after they die, thus allowing you to advance the technological level of humans vastly in a short amount of time and allow access to a larger amount of resources that could be gradually "mined" for years
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**This question already has answers here**:
[What would be the tallest possible height for humanlike creatures in earthlike conditions?](/questions/51686/what-would-be-the-tallest-possible-height-for-humanlike-creatures-in-earthlike-c)
(5 answers)
Closed 7 years ago.
What genetic traits would be needed to have a human that is "normal" in all aspects, but roughly 50 to 80 feet tall?
[](https://s-media-cache-ak0.pinimg.com/564x/7d/2d/44/7d2d4455aeeaa1d1c0353c2598de734a.jpg)
This doesn't seem *completely* out of the realm of possibility considering some whales can be 10x larger than other species of whale. What would prevent a line of humans from giving birth to gradually larger and larger children?
This question is part of the [Anatomically Correct Series](http://meta.worldbuilding.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798).
[Answer]
Because of the square-cube law mentioned already, a 50 foot human would weigh over 50 tonnes. I do not see a possible way for a biped to support such a size, especially not one of human descent. How big your giants can get depends on how human you want them to look. In the real world, very tall people are caused by excess growth hormone rather than genetics, which is why they often have many problems. [Giant Ground Sloths](https://en.wikipedia.org/wiki/Megatherium) stood around 5 metres tall and weighed around 5 tonnes, however I believe they were tripedal, having a load-bearing tail. If an alternate evolutionary path is acceptible for you then your giants could have similar tails.
For giants humans to exist, they would need a series of adaptations:
* **Bones**. Proportionally thicker bones are needed to cope with the excess weight (compare
a horse to an an elephant). This is especially true for the legs bones.
* **Muscles** would be larger/stronger for the same reason as above. You could also increase the efficiency of the muscles - Apes have shorter muscle
fibres than humans which makes them a lot stronger pound for pound at
a trade-off of losing your fine motor skills.
* **Shorter legs; longer arms**. As you scale up, relative leg length
scales down in order to preserve balance. The bigger they are, the
harder they fall, which is why longer arms would be needed for
balance, stability and for softening impacts. I would expect the
distribution of mass moves lower and lower to keep a low-centre of
gravity, so giants may have thinner upper bodies or less broad
shoulders.
* **Internal organs** would have to compensate for extra body mass. Because volume scales faster than height, the heart and lungs
become less effective (although lungs also increase in efficiency
as surface area increases) and would need to be scaled up higher.
Your giant would likely have a deep ribcage and massive heart.
* **Facial features**. Larger eyes only become effective up to a certain point. The eyes of a giant would be much smaller in proportion to his head
than a regual human. The surface area of the nasal area would increase faster than the length of the nose, giving your giant a much keener sense of smell (I know, plays right into the fairy-tails). The larger nasal cavity and larynx would also give your giants deeper voices.
* **Brain**. Our brains use vast amounts of energy so the brain would probably scale up a lot slower than the rest of the body. Extra mass and the accompanying buffs to your senses would be more taxing on your giants brain so the brain could scale to compensate, how much it scales depends on how intelligent you need them to be.
* **Blood pressure.** Giants would need to keep blood pressure high in order to circulate blood and oxygen around the body. Elephants have very tight skin on their feet to increase the blood pressure in their limbs as the blood needs to travel against gravity for quite a height. Elephants also have large fatty pads on their heels to cushion the impact of walking. Your giant's feet may not resemble a humans.
* **Diet**. As the intestines scale up, digestion becomes easier. More body mass means higher body temperates which means more nutrients can be extracted from food. Giant humans may lean towards vegetarianism.
I have also read that the size of a certain reproductive organ scales up more with giant animals but I chose not to read up on that one. I would reccomend keeping your giants under 4 or 5 metres as the largest prehistoric mammals never peaked above that (even quadrupeds) and the largest bipedal animals of all time - the therepods - didn't really exceed 3 or 4 metres at the hip and it's specualted the atmosphere contained a lot more oxygen in prehistoric times. Even a slimmer 3.5m giant would weigh over half a tonne.
[Answer]
Welcome to the tyranny of the Cube-Square law. It goes something like this
*Mass increases proportional to the cube of an objects size*
*Strength increases proportional to the square of an objects size*
It comes down, fundamentally, to muscles. Our muscles are bundles of fiber that can expand and contract when ordered. The more fibers you have, the stronger you are. A man with strong, bulging muscles has lots of muscle fiber running the length of a muscle, where as a skinny man has only a few. To pack in more fiber, I need a larger cross-section (A larger planar area, thus the square) to fit the fibers in. If I increase the cross section of a somehow square muscle from 1x1 to 2x2, it has 4 times the strength.
Total mass is dependent on volume. If I Increase the dimensions of a 1x1x1 cube to 2x2x2, its volume is now 2x2x2 (8! 8 Whole times!) times larger, hence the cube in cube-square law. Mass can be treated as volume \* density, so an object twice the total size weights 8 times as much.
Now, ignoring all the issues of circulation or bones snapping under their own weight, a giant that's a modest 3 times the size of an average human would have **9 times the strength**, but **27 times the weight**. It's doubtful he would even be able to stand.
[Answer]
**Place them on a low-gravity world.**
It's definitely possible to create anotomical structures on the size scale of a giant. Large therapods had legs of the right scale for such a beast and some, like [therazinosaurus](https://en.wikipedia.org/wiki/Therizinosaurus), even had arms approaching those that a proportional giant would have. However, it's probably not possible to create an anatomically correct giant of that size that lives on Earth. The biggest problem with having a 50 to 80 foot tall humanoid is blood circulation. Unfortunately, there probably isn't much you can do about blood circulation while remaining 'humanoid'.
Looking at the lower end of your range, around 50 feet, we encounter sized at which your giants are about as tall as a dinosaur like Spinosaurus is long. However, Spinosaurus and other gigantic carnosaurs had mostly horizontal bodies, with their heads about level with their torsos and hearts. Sauropod dinosaurs also follow this general body plan, though some probably raised their heads to some degree, at least 20 feet or so above their hearts.
The easiest way to get around the problem of blood pressure from being tall is to weaken gravity. On a planet with only .25 g, for example, pressure differentials for a 50-foot high giant would be similar to those faced by a 12-foot high humanoid, which is well within the realm of possibility.
Beyond that, you should expect your giants to have proportionately shorter limbs, since long limbs would be effectively more fragile for a huge creature, gigantic barrel chests to contain proportionately larger hearts (blood pressure is still a problem, even with our lower gravity, just not as much of one), and proportionately thicker arms and legs.
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No, it is not possible. Not even remotely. At least not with Earth mammalian biology being what it is. Bones can only get so big. But hey, we had some pretty tall dinosaurs walking around, so why not a giant human?
It comes down to joints, blood circulation, and a bunch of other fun stuff like that. Basically, once you reach a certain size our basic biology just can't keep up anymore. An 80 foot giant would swing an arm, and snap its bones in half, as the muscle power required to move its limbs would be greater than the strength of its bones.
If we were devising a different creature, with multiple hearts, a different circulatory system, etc. it might work out, however. Some of the earlier, massive dinosaurs are believed to have had 2 hearts anyway, so it can happen.
If you look at the history of our world in fossils you will notice that even the dinosaurs got progressively smaller as we get closer to modern times. Same with the megafauna that dominated our planet a few hundred thousand years ago. The more complex our biology became, the smaller we evolved to be. This is not a coincidence. Even blue whales, whose weight is suspended by the oceans they live in suffer from diseases related to their size by the time they die.
At best you are likely to reach 15 feet, but what we end up with, does not look human.
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[Question]
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For a highly intelligent avian dinosaur whose grasping and manipulating appendages have all but vanished, there are options : for the species to evolve beaks that are better fine manipulators, or continue to writhe in abject mediocrity. So the question is - which type of beak might the birds evolve to serve as fine manipulators in place of hands?
Examples of fine manipulators -
Primate hands are fine manipulators.
Claws are NOT fine manipulators because they only have two points of contact, making them inherently less dexterous
How do you make a head and beak with only two points of contact more dexterous like a limb with 3 or more points of contact ?
[Answer]
# TL;DR
I see various options:
* Beak divided in multiple partially patch-covered 'lip/fingers'.
* Precise prehensile tongue.
* Fingers in wings.
* Use wings to walk to free the already hand-like feet.
* A combination of the above.
# Manipulator beak
Seeing as the always-mentioned crows [are able to create tools even to make other tools](https://en.wikipedia.org/wiki/New_Caledonian_crow#Tool_use_and_manufacture) using mainly their beaks, I don't see this as far-fetched as other answers suggest. So,
>
> which type of beak might the birds evolve to serve as fine manipulators in place of hands?
>
>
>
Like [this answer](https://worldbuilding.stackexchange.com/a/36014/18248) suggests, a softer patch of tissue halfway along their beak would certainly help the gripping, without losing the sharp and hard usefulness.
But why stop there? This tissue would give them some lips of the sort. A more complex control (for example, closing one side of the mouth while keeping the other open) of these 'lips' would help even more with the manipulation, and could lead to a physical split of each 'lip' into two (or more) half-lips. So they would end up with **a partially tissued beak divided into four** (two up and two down) **'lip' parts**. Those would really look (and act) like sharp-clawed fingers! If you add a precise prehensile tongue, that should do quite the trick. It could even allow for a **simultaneous use of the mouth for manipulating and eating** (with two 'finger/lips' holding something and the other two eating).
Of course, this is quite a weird approach (but my favorite!). So let's take a look at others.
# Wing fingers
As pointed out by bowlturner in [this answer](https://worldbuilding.stackexchange.com/a/36054/18248), **some fingers in the wings could be used for hands** (after all, they ARE hands). I would go for the pterodactyl wing which gives more fingers and it also has a more similar bone structure to the bird wing:
[](https://i.stack.imgur.com/PcKFp.jpg "From top to bottom: pterodactyl, bat and bird")
(source: [ncse.com](https://ncse.com/files/images/Wing_morphology.img_assist_custom.jpg))
This approach, however, leaves the hands quite useless while in flight. And carrying loads in the wings in flight doesn't sound like a very good idea.
# Feet
Bird feet, of course, are already quite good for manipulating. Many current birds use them as such.
Maybe there's a little room for improvement. Pads in the upper pads of the fingers, for example, could allow them to **walk while holding something**, which would be useful, althoguh probably not very practical.
A more... let's say ridiculous approach would be **using the wings for walking on land, leaving the feet free to act as hands**. After all, wings on land are not very useful, so you've got two unused limbs while underusing two very useful others. Those fingers suggested in the previous section would come in handy when walking on trees. One problem would be takeoff and landing, but could be solved by switching to the feet just for that moment, or taking off by dropping from a height.
# All of them
Lastly, you can always **combine two or more of the above**. Don't be afraid of doing something weird. Mother Nature has come with very weird stuff herself.
[Answer]
The issue with this is the rigidity of the beak. Beaks evolved from snouts as dinosaurs that lived in the trees and then became avian needed them to do things like strip bark from trees to get at insects, or crack open nuts and seeds for food. All of those things required them to have rigidity along the length of the beak, as well as a hard point to do the cracking or grasping.
A way around this would be where a dinosaur evolved a softer patch of tissue *halfway* along their beak, on either the top, bottom or both, where the beak closes. Imagine a U-shaped section of the bottom part of the beak that was soft, spongy tissue with the rest of the beak being regular hardened keratin. This would mean that they would be able to grasp sticks in their beak without worrying about losing them due to twisting forces, and if they had a strong tongue they would also be able to have a limited range of movement on the rudimentary tool. This would also retain the strength along the length and in the tip of the beak for the regular jobs that a beak evolved for.
The flexibility of primate hands is very important for grasping and manipulating tools, but soft pads are also important for gripping tools without slipping. The beak solution above might get them some way towards making a further leap in intelligence, but I think hands might be the only way you truly develop technology, not just rudimentary tool use.
[Answer]
There are several issues which make this something of a non starter.
First off, a beak is an adaptation so a bird can have hard cutting surfaces like teeth without the weight of a jawbone and teeth. Very early birds did indeed have teeth, but had essentially lost them by the end of the Jurassic era, and by the end of the Cretaceous, I don't know of any examples of birds with teeth. (I may be wrong about this, but any remaining birds with teeth in the Cretaceous era were very rare indeed).
As hard cutting implements, they only offer two points of contact (or four if you go right across the mouth). A beak would resemble a crab's claw in terms of how it could grasp and manipulate an object.
The next objection is the distance between the eyes of the bird and the beak itself. Put a pencil in your mouth crossways the way a bird can hold a twig, then try to look at it in fine detail. Predatory birds have evolved front facing eyes adapted to seeking out prey at great distances. In human terms they are far sighted. I suspect the adaptation to have clearly focused vision to go from seeking prey from high altitudes to looking at something at the "end of your nose" might be a lot of work for limited return. Once again, look at a macro lens on an SLR type camera, then a long distance lens. Now look at very highly developed zoom lenses which can go from Macro to long range. The complexity, weight and price of such a lens is comparable to the amount of metabolic tweaking needed to evolve an organic analogue. (As a BTW, birds like ducks would never be able to evolve such an organ since their eyes are more to the sides of their heads to look for threats).
Finally, since there is only one beak, the amount of manipulation possible would be very limited. Even the science fictional "Puppeteers" from Larry Niven's "Known Space" cycle had two heads ending in a mouth adapted as a manipulator each (hence two "hands"). I never found this totally convincing, since the Puppeteer would have difficulty seeing what it was doing when working with its "hands".
[](https://i.stack.imgur.com/WECIt.jpg)
In the real world, this isn't even necessary. Dinosaurs, like every other living species on Earth, adapted pre existing structures which could change with evolutionary pressure. Tyrannosaurids could potentially have had evolved to grow longer and larger arms, provided that it gave the creature some advantages that outweighed the extra size and bulk. A Tyrannosaurid evolved to "fish" might regrow arms to scoop fish out of the water, for example. Since you speak of beaks, a flightless bird like a Terror Bird has stub wings, and the potential to regrow them should this somehow become advantageous. An evolving Terror Bird with greater intelligence and a capacity to manipulate objects with repurposed wings (which in the long run are *very* repurposed fish fins) would seem to be where you are going with this.
Inside of a wing are very long finger bones to create the lifting surface (covered with feathers), they can scale back into hand like structures, while the beak and head are reproportioned to deal with the shifting centre of gravity and the ever decreasing need to kill and carve up prey with the beak (hominids gradually reduced their jaw lines since crushing nuts with stone hammers and cutting meat with flint knives was much easier and more efficient than chewing through it).
[Answer]
Well, given that beaks are hard, the solution is obvious:
Have the avian dinosaurs use their closed beaks for breaking stuff (like other dinosaur's heads), the open beak for grasping (between lower and upper beak-bit) and their **tongues** as delicate manipulators.
[](https://i.stack.imgur.com/HvYkY.png)
You can then go ahead and fork the tongue or whatever you want.
[](https://i.stack.imgur.com/dXTTX.png)
[Answer]
>
> How do you make a head and beak with only two points of contact more dexterous like a limb with 3 or more points of contact?
>
>
>
You don't.
Birds can do many things with their beaks today. But beaks are not an end all be all for item manipulation. Nor are they likely to develop into such. More than likely the birds will use other forms of manipulation to get the desired outcome.
Take parrots for example. Parrots will hold something in their feet while they simultaneously use their beak to work it as well. Many other birds use their feet as an auxiliary manipulator.
[](https://i.stack.imgur.com/9LNSY.jpg)
On top of that, if you expect 'evolution' to work it's magic to help with tool use, there is a very good chance that a finger or two could 'grow' from the 'wrist' of the wing. Like bats or pterodactyl. So between feet and 'thumbs' and the beak they could have quit a range of abilities. However to get something that is very manipulable for a mouth, it won't really be a beak any more, maybe a trunk. On top of that would it make sense to have your main manipulator the entry point into your digestive system? and so close to your eyes? Even an elephant's trunk is long, and is a nose not a mouth.
[](https://i.stack.imgur.com/aThp9.png)[](https://i.stack.imgur.com/sixNt.jpg)
There are even many people who either were born without arms or lost them. They use their feet as hands too. This didn't even take evolution.
[](https://i.stack.imgur.com/GevGK.jpg)[](https://i.stack.imgur.com/q3Abi.jpg)
[Answer]
with some skull tweaking, the beak could possibly maybe be split in 3 or 4 pieces, opening up like a flower.
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[Question]
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I'm creating a world my protagonist will visit with humanoid inhabitants that have a peculiar feature: their eye sockets are in the palms of their hands, not unlike the Pale Man Pan's Labyrinth.
[](https://i.stack.imgur.com/oiYM2.jpg)
The big difference is that they are not evil. They are regular people in a regular society just like humans, except they have this one distinct feature.
What are some unique differences in day-to-day living they would experience?
[Answer]
lots of great answers here, there's something else that people haven't considered though:
## Depth perception
We perceive depth using a concept called [Binocular Disparity](https://en.wikipedia.org/wiki/Binocular_disparity). What this means is that we get two different images through our eyes, and our brain merges the two into one image, perceiving the difference as "Depth". The greater the shift in location horizontally between the two images (in the human case where our eyes are horizontally separated), the further away the object is.
Now, we learn *just how far away* an object is through trial and error. This is difficult enough, but it's made easier by the fact that the relative position of our eyes to each other is constant... oh. Woops. This guy now has a serious problem. If he wants to figure out how far away something is, he:
1. Has to have both eyes "looking" at it.
2. Has to know what that specific disparity amounts to in terms of distance *depending on how he is holding his hands*.
Say what? Well, if he holds his hands out wide, the disparity between the images from the two eyes will have a greater shift than if he holds his hands close together. And that's assuming he's good at holding his hands on a single plane. I have no idea what effect it would have if one of the eyes was at an angle. Let's not even start thinking about how you'd keep track of the mechanics if their hands were moving!
That's hard enough to write, let alone to do. That's an immensely difficult calculation, and while he'd probably learn to do it instinctively to a certain extent (brains are amazing), the chances are that they'd have to develop a coping mechanism whereby if they want to judge depth they move their hands into a "known configuration", like, hey, holding their hands in front of their face. Funny how it comes back to that.
There's something else related though that would be even more weird:
## Conflicting Images
I hold one hand with the eye facing in front of me. I hold the other hand with the eye facing backwards. Result: AAARRGGGGHHRHGGFGGHR \* brain melt \*.
There's something else weird you can do to screw with eyes, that's called [Binocular Rivalry](https://en.wikipedia.org/wiki/Binocular_rivalry). It's where you feed two different images into the eyes and watch your brain struggle to figure out wtf it is looking at. Generally, people either have a "dominant eye" which comes out on top, rendering you blind to the other image, or they find their vision switching between the two as they fight for dominance, or in really weird situations, the brain tries to *merge the two images together* into one seriously screwed up combination, depending on how similar the images are.
Now, this happens because our brains expect very similar images. It's likely that a species that didn't evolve with such a convenience would likely develop a VERY different brain. Maybe they'd even split the images coming from the two hands into different processing nodes in the brain, and maybe they could even see in two directions simultaneously. That's going to result in a being that on a psychological level differs massively from humans. It's also likely that they would treat the input from the two eyes independently, and on the whole they'd probably be epic ad multi-tasking. On the other hand, they would have hardly any depth perception at all, having to rely on visual cues like shadows and partial obscurity behind other objects to judge distance.
I'll tell you something, camouflage clothing becomes amazing under those circumstances. The chameleon would be their worst nightmare. All you'd have to do to sneak up on them would be to have a bunch of tall people far away and a small person walking up a lot closer, they wouldn't know till the last minute that one of them was a lot closer than they thought.
Death by Parallax. Awkward.\*
\*Yeah, alright, they'd probably develop other coping mechanisms for judging immediate proximity. But that isn't as funny.
[Answer]
**Hands are now useless.**
We use our hands to carry lots of things. This generally involves curling our fingers around something, which in turn blocks the palms of our hands.
If we had eyes on our palms, they would be blocked whenever we need to use our hands for something. Meaning that we wouldn't be able to see. This is not something that is acceptable. Therefore, these people will have to significantly reduce the amounts of things they do with their hands.
I prefer to see when I drive a car. Not being able to see generally leads to people dying.
[](https://i.stack.imgur.com/StD1z.jpg)
Image taken out of context from [A Double Shot of Recovery](http://adoubleshotofrecovery.com/seeing-the-world-through-the-eyes-of-others/), a blog that's completely unrelated and was only found by me ~30 seconds before adding this picture.
You can either give up using your hands or give up vision. The choice is yours.
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**Random other things I thought of later**
* Injuries to hands (e.g. burning, lopped of limbs) would severely hurt or blind eyes
* Your hands may be more sensitive, because of more nerves in the area (just a guess)
* It's much easier to get dirt, dust, etc. in your eyes
* Glasses are much harder to wear (are monocles all the rage now?)
[Answer]
By spreading hands you could significantly increase perception accuracy of distance to distant objects ([stereopsis](https://en.wikipedia.org/wiki/Stereopsis)),
Basically you can become human(?) version of [coincidence-rangefinder](https://en.wikipedia.org/wiki/Coincidence_rangefinder)
[Answer]
* They could cover more of their heads when it's cold, like pulling the hat all the way down to the nose
* Can't do many two-handed things, but maybe there's already a lot of disabled-people tools for living in a one-handed world? Every two-handed actions removed eye sight
* They can stick their hands around corners. Hide-and-seek champions, yo (they can be covered in things and only show a little bit of themselves for periscopic view
* Maybe more speech-to-text type things for digital writing, pens still work as normal
* participates in fewer activities that require depth perception
But when you say the protagonist "visit with humanoid inhabitants that have a peculiar feature" then you're implying their entire society is like this? How would you answer this from an evolutionist perspective?
you now have people that easily can get up-close to anything in arms reach. Are they capable of this due to how they get food? Does the eyes have a good microscopic-like view of things, maybe they are used to inspect their food closely?
The problem with this question is that it's easy to picture what a human person who suddenly had his eyes in his hands, which means the question of "day-to-day-impact" is harder to answer when we are actually dealing with humanoid aliens.
[Answer]
1. you likely wouldn't shake hands.
2. your reactions would be slower, since your eyes have a much farther distance to send impulses.
3. it would be much easier to blind someone. Breaking an arm or just a strong punch could damage the optic nerve.
4. "I was just rubbing my eyes"...
5. It would be very difficult to see where you are going when you are carrying anything at all.
[Answer]
Because their eyes are so close to fingers, they might become very good at doing small, precise work that utilizes tools that are usable by fingers, instead of whole hands. For example, fixing mechanical clocks would be much easier, because your hand doesn't obstruct the view as much.
That might mean that during the evolution most of their kind would mostly develop eye-sight that's perfect to see small objects close to eyes.
However, my own theory sounds improbable unless one of the first things they develop is a way for their eyes to see in environments with poor lighting, as the hands would just block natural lighting sources while doing fine-work.
[Answer]
Hand dexterity becomes synonymous with situational awareness.
Carrying objects is trickier: one cannot use his/her hands easily, because of the pressure on the eyes. Backpacks are way more common than handbags.
If the eyes are removable, like in the movies, **and** interchangeable, swapping eyes between two people can be useful for spying - or, in a literal sense, put oneself in other's position.
If the eyes work outside one's body, eye [selfie sticks](https://en.wikipedia.org/wiki/Selfie_stick "selfie stick") can be useful.
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[Question]
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**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
It seems that my ability to create interesting creatures is limited by the need for sexual reproduction, which is absurdly useful, but also rather limiting, method of sharing genetics. I acknowledge that any sapient species will almost certainly have some means of swapping genetics, but that does not mean a traditional male-female role must exist.
I'm looking for some alternate approaches with which an 'advanced' species, at least sentient if not sapient, could evolve for exchanging genetics. I'm looking for any novel approaches for genetic swapping which make logical evolutionary sense. Presume a world that is roughly similar to earth, though your welcome to tweak specifics to fit any need. Any creature must be roughly earth like, meaning carbon based, multi cellular, specialized organs, etc etc. I'll give some lead way for methods of genetic encoding beyond DNA if this supports an interesting concept.
Genetic division does not need to be as rapid as with sexual reproduction, a species that gets enough novel DNA to make evolution of more advanced features like sapience possible is fine, even if it takes five times the generations due to a slower dna exchange mechanism.
What I mean by avoiding sex means avoiding the traditional male-female sexes or traditional "two creatures meet up and mate with intent of creating at least one more creature with half their dna each". It's okay to have specialized sexual organs, transfer of dna between creatures etc, so long as it is separate enough from traditional matings within the animal kingdom.
As I myself already stated I don't considered tri-gendered creatures to be viable ([How to handle a tri-gendered race](https://worldbuilding.stackexchange.com/questions/17388/how-to-handle-a-tri-gendered-race)). Hermaphrodite creatures are interesting and novel, but I'm going to exclude them as possible answers simply because I'm aware of them and the interesting options they offer already.
What other novel methods could organisms generate to allow genetic exchange?
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The simplest solution IMHO would be a symbiotic bacteria that is **not** trapped inside the cells, but instead lives at least partially outside the host cells and can be transferred between hosts.
Some bacteria in our digestive system actually are like this and their health and genetics does have an effect on the health of the host. Some larger parasites are potentially also very close.
Essentially you want a small species with fast life cycle living inside the host in a symbiotic relationship that can spread from host to host. Such species can potentially have arbitrarily large influence on the host, some insects can't reproduce without their *parasites*. And many parasites do affect the brain.
Not sure if this would necessarily speed up evolution, but it would create an alternate method of genetic transfer between hosts. Which is what you wanted. It is normal for genetic material to get transferred between host and parasites even.
For faster evolution, you need greater evolutionary pressure. There should be clear benefits for being the smartest guy around. Not sure if that is realistic. Thinking is fairly energy intensive. And after a certain point societies form and social evolution becomes the dominant factor.
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> What I mean by avoiding sex means avoiding the traditional male-female sexes or traditional "two creatures meet up and mate with intent of creating at least one more creature with half their dna each". It's okay to have specialized sexual organs, transfer of dna between creatures etc, so long as it is separate enough from traditional matings within the animal kingdom.
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I think this condition holds the key to the answer. While there is an evolutionary need to mix DNA in reproduction (and thus, for specialized organs, which are sexual by definition), using half the DNA of two organisms is a bit arbitrary. (It's arguably the simplest solution, but definitely not the only one.)
I propose a race of unisexual creatures. Every member of the race has two reproductive organs; let's call them a "giver" and a "receiver". When two organisms have sex, the giver deposits *some* of its DNA into the receiver (much less than half; say 1 - 5%). **The receiver doesn't contribute any DNA; rather, it "compiles" the DNA of numerous partners until it has a full set of chromosomes from which to create an offspring.** At this point, pregnancy and childbirth occur and more or less resemble those of humans.
A species evolving this way would suggest an early threat to their survival that required more genetic diversification than the male-female method would have provided, such as a predator or virus that adapted to specific gene sequences. I also suspect that early in their evolution, each organism's giver secreted a random combination of genes, but as they evolved, they began secreting only their best genes, and secrete very similar genetic code every time. This would in turn drive the need for many mates, rather than mating with one organism (or yourself) many times.
Should you use this idea, I hope you enjoy exploring how this biology would affect their attitudes on sex and relationships.
EDIT (In response to your comment):
For what it's worth, I don't think common DNA is the *only* factor that motivates a parent to raise a child. Further, if the evolution I proposed did occur because of a survival necessity, there would be a reason for the organism to also evolve in a way that ensured a maternal instinct. There are several ways this could occur. Perhaps when one is pregnant, the body produces a specific hormone that stimulates the maternal instinct. Perhaps the mother contributes as small an amount of DNA as the fathers (or smaller), but the mother's DNA is always a specific gene sequence that is uniquely valued and/or responsible for how the organisms identify one another (e.g. a particular scent).
Later in their evolution (and as their society develops), they will also be motivated by the knowledge that they "designed" their offspring by selecting the mates, as well as by the social contract stipulating that they must nurture their own offspring so that in return others (whose offspring carry their DNA) will do the same.
And of course, there is the evolutionary imperative that one's *species* survive, as well as one's specific DNA. It stands to reason that this drive would be stronger in a species where offspring possess little or none of their parent's DNA.
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There are many organisms on earth that have decoupled genetic recombination and reproduction. What you are looking for is called [Horizontal Gene Transfer](https://en.wikipedia.org/wiki/Horizontal_gene_transfer). This is when two organisms exchange DNA and there are lots of different ways it can happen. Many organisms have dedicated systems for exchanging genetic material, like a pilus for bacterial conjugation, but it can also happen through viruses, and even simply by accident. Many cells will add foreign pieces of DNA to their genome if it gets in to their nucleus. These systems are seen mostly in unicellular organisms, but there are multicellular examples and there is no fundamental reason why multicellular organisms can't utilize horizontal gene transfer. In fact some researchers believe from even [humans contain some genes that we acquired through horizontal gene transfer](http://www.genomebiology.com/2015/16/1/50). (In case there there is a paywall to that journal here is a [news article about it](http://news.sciencemag.org/biology/2015/03/humans-may-harbor-more-100-genes-other-organisms)).
In the end DNA, or any other genetic material, is just a physical molecule. An organism can make as many copies as it wants, translate it into different forms, and spew it all over the place. It's very easy to imagine an organism that makes copies of some or all of its DNA and simply shares them with other members of its species through any sort of direct or indirect physical contact. Just to give an example, imagine an alien organism that constantly excretes chunks its genome into the environment. It produces an egg with a full genomic complement, and then samples the environment for DNA from other individuals and uses homologous recombination to swap out the old for the new.
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Most plants, as well as sessile aquatic animals like corals, do reproduce sexually, but since they don't move about they tend to do it either by releasing their gametes into the surrounding medium or attach them to a mobile proxy species (pollination).
There are also many mobile animals (fish, amphibians, spiders) that do not need to come into contact in order to reproduce - the female deposits her eggs and the male fertilizes them outside of her body. Usually there is some kind of ritual involved to get the female to deposit her eggs, though.
Sexual reproduction does not require the two individuals to come into contact with each other.
The real question is how to justify such a system in an advanced, mobile, intelligent species. Internal sexual reproduction is more energy-efficient and allows greater choice on both the male and female's part.
One possibility is a mostly solitary species where the male and female almost never come into contact. Instead, the female deposits her eggs in a hard-to-open container protected by some kind of 'puzzle lock', and leave clues for the male, who has to figure out how to open the capsule in order to fertilize the eggs. This would allow the female to select for more intelligent males (since only they could figure out how to find the capsule and open the lock). The males, meanwhile, would prefer more challenging puzzles since it would demonstrate better constructive abilities on the female's part. This could accelerate the development of high intelligence without social behavior (similar to that of an octopus), leading to a very alien species.
Another could be a slow-moving species that co-evolved with another, flying 'pollinating' species, allowing them to spread their DNA much further to distant populations (perhaps because the species is prone to recessive genetic diseases). The pollinator species could eventually function like a domestic animal that becomes a proxy allowing them to mate, while getting food in return. Owning pollinators becomes a sign of fitness since it requires the sapient creature to collect more food in order to attract them; having more food allows one to attract more pollinators, allowing them to mate with many individuals at once.
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If you want a weird one which actually exists in real life:
One option based on some real life bacteria is gene-stealers.
What happens when a colony of bacteria is introduced to a new environment but is starving?
There's good odds that some of the other bacteria already resident will have genes for handling the food sources available in that environment but how to get those genes?
There's a species of bacteria Salmoneella "LA-22".
It carries a phage in it's DNA. Sometimes the phage activates and kills some of the members of the colony. This isn't much use except when a colony is placed in a new environment with food sources they cannot digest.
Sometimes the phages will infect a resident bacteria but instead of packaging up a copy of the phage it will instead grab a chunk of the original residents DNA.
[](https://i.stack.imgur.com/WJxeD.jpg)
Sometimes the phage will return to the original colony and pass that gene to one of it's members who than then avoid starving and survives.
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What about Lamarckian evolution? Imagine a planet in which multiple species are hosts of the same basic symbiont organism and the latter evolves rapidly during the life of the host.
Maybe assume that the reproduction of both the host and symbiont organisms are somehow linked in a feedback loop. If the symbiont evolves significantly during the life of the host then it would be useful to pass on the final state of symbiont DNA to host offspring.
Ideally, successful combinations of host DNA and symbiont DNA could be passed on and this process will require the exchange of both. The host may retain male and female distinctions, or may be asexual, but the symbiont may then introduce additional classifications and compatibilities beyond that.
Mitochondria can be viewed as a symbiont - and this DNA is only inherited by the female but perhaps its possible to imagine other perhaps less well integrated symbionts (fungi or plants) where things might be different.
After all, most plants have both an asexual and sexual phase which alternate - so combine that with animal male and female and you end up with multiple phases of male and female according to the alternating generations of the autotroph symbiont which would complicate replication of the host (the advantages conferred by the symbiont must be suitably useful for this situation to persist of course).
This is all quite wacky, but then so is the question...
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It is entirely possible for [retroviruses](https://en.wikipedia.org/wiki/Retrovirus) to transfer genetic material between individuals so it's reasonably plausible to imagine a world where endemic benign viruses have made actual sexual reproduction unnecessary and becoming pregnant is essentially a viral infection. In fact that there is a theory that in utero fetus development is, at least in part, in fact a side effect of a virus not unlike HIV.
In the [Mass Effect](https://en.wikipedia.org/wiki/Mass_Effect) universe the Asari are an all female species who don't have sexual reproduction in the usual sense but rather use the DNA of others (regardless of species) as a randomising factor on their own DNA.
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If it make sense, from the point of view of evolution, that we have to reproduce and to die, it is because we are not able to mutate during our life, we have to create a new beings to allow mutation (and sexual reproduction to allow for mixing genes).
So an answer is : just forget about reproducing, and dying. You can imagine a species which simply clone itself (for example by lying eggs, from which a perfect copy of yourself emerge after a while).
Then if a creature is subject to enough random mutations during its life (e.g. due to intracellular processes or more natural radiation that what we get on earth), its clones can evolved in a different way than the original, and you can reduce the need for genetic exchange.
You can go a step further, by assuming that each member of this specie produce a kind of virus in its saliva (or anywhere else) that is able to inject part of its DNA into cells of other members of the specie, and the result is : when two kiss they actually mix their genes, without need of reproduction.
Note that in this scenario searching for the best partner still make some sort sense, since you will directly "inherit" part of its genetic features.
Note also that such a process can be extend between members of different species.
Of course there is problems, for example if only some part of you partner is affected, he will grow strange unequally distributed mutations. You can avoid that by "sharing" your genes with your partner's clones in a early stage of development (e.g larva or egg) that you can easily affect as a whole.
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The Gourmandians have a unique genetic structure. Seventy percent of their DNA/chromosomes is what we have labeled 'base DNA'. The other thirty percent is what we have labeled 'adaptive DNA'.
In a Goumandian's stomach, there are clumps of cells with incomplete DNA. Anywhere from five to ten percent of the total DNA is missing, but always from the adaptive chromosomes. These incomplete cells are also undifferentiated.
When a Gourmandian consumes food, some of the DNA from the plant or animal eaten is absorbed by the incomplete cells. If the newly complete cell is viable, it naturally migrates to an incubation sack and begins mitosis. If it is not viable it drops into the stomach with the rest of the food and is digested.
Once the newly altered cells reach a sufficient quantity, they break up and are absorbed into the blood stream. They travel throughout the body, a few ending up in most or all major systems. There, they automatically adapt into the same type of cell; muscle, bone, organ, etc. They continue to reproduce, having what is best termed as a gentle rivalry with the existing cells. There is not danger or discomfort to the Gourmandian, but whichever version of the cell is more efficient in that role, will win out. Either the new cells with stop reproducing or the old cells will slowly be replaced.
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Would something like that be sufficiently different for you?
You could also have something like a three gender species where the mother contributes forty percent of the DNA, father type A contributes thirty percent and father type B contributes the remaining thirty. Or forty/twenty/forty, with father type B being rare and thus those with good genes are highly sought after and not generally allowed to be in a monogamous (trigamous?) relationships.
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Suppose that Khufu, pharaoh of Egypt and builder of the Great Pyramid of Giza, was introduced to the idea of an amusement park.
More specifically, suppose that he was visited by a time traveler and was invited to go on vacation with said traveler to the 21st century. On this vacation to a modern amusement park, he became so enthralled with roller coasters that, on returning to his time (which is at the point before construction on the Great Pyramid has begun, but after the foundation has been created), he decides to pour all his resources into building a roller coaster instead of a giant tomb. After all, roller coasters are fun, and it may well become a Wonder of the World for generations to enjoy, making his legacy unique compared to all other pharaohs. And besides, he can still build a nice portal to the afterlife in the form of a smaller, more economical pyramid, later.
And so, the prime question:
**What is the biggest, most complex, most enjoyable ride that Khufu can construct within 20 years, using the same Egyptian-level technology and manpower that would have otherwise been used for building the Great Pyramid? Assume the structure is located on the Great Pyramid's foundation. Provide dimensions, and give explanations for technical elements such as loops or vertical drops, etc.**
Bonus Questions:
1. What is the most practical way of powering the roller coaster? Are there solutions besides slave powered ascent ramps?
2. What is the maximum passenger service rate? (Number of individuals per train, number of concurrent trains running at a time, etc.)
3. How safe is it? (Fatalities/Injuries per coaster run)
4. How long can it remain functional? (Provided 60 years of active service to the end of the Old Kingdom in ~2490 BC, then total neglect there after. Can the structure and cars/trains be restarted with minimal repairs up to a certain point in time? We want this to be a Wonder of the Ancient World, is this possible?)
5. How would history be affected? Specifically, would the Scientific and Industrial Revolutions have happened earlier and elsewhere had the Egyptians been exposed to the physics of movement via roller coaster mastery?
Some supplement material:
The Great Pyramid took between 10 and 20 years to build with between 15000 and 40000 workers. It weights 5.9 million tonnes, and its dimensions are accurate to tens of millimeters in terms of alignment and average deviation from flat.
Sources:
<https://en.wikipedia.org/wiki/Great_Pyramid_of_Giza>
<https://en.wikipedia.org/wiki/Roller_coaster>
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January 2017 Updates:
Here is a slight addition to improve on the original prompt:
Khufu knows full well that the marvelous steel wheel, rails and bearings he got to see and experience on his trip are not a viable technology for his time. What he really wants to do is to try to replicate the experience as nearly as he can, namely:
1. Fantastic, fast traversal of some kind of track which is open to the public (for a fee). This may devolve to it being a glorified bobsled track, but the closer to the modern experience, the better.
2. Has tiered lines like modern amusement parks: **The Standard Line** is for commoners and tourists who have paid the park entrance fee. The **Fast Line**, for those who pay more or submit to a schedule. The **Royal Line**, reserved for the Pharaoh and his friends only.
3. Designed to operate for centuries. As specified above, it will fall into a period of disuse for a time about 60 years after its completion, but say around 1000 BC, the park is started back up again. How well does it weather over ~1500 years of neglect? The Wonders of the Ancient World were sites that ancient tourists visited with good reason, and this site needs to be included in that same list in this alternate timeline.
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Aside from the other issues noted, the stone foundation of the roller coaster would provide a very jarring ride for the patrons. Wooden and metal roller coasters have some ability to "flex", which reduces some of the forces transmitted to the riders. A solid stone foundation will not.
All is not entirely lost, however. A stone foundation of an ancient roller coaster would require a much better cart, and Egyptian war chariots could provide the model for a roller coaster cart in this setting. Rather than the small wheels we associate with roller coasters, the war chariot has very large wheels, made of relatively lightweight and flexible wood. The axle and the body are also light and flexible to absorb the jolts that would be expected from a high speed chariot charge across the battlefield (trying to shoot an arrow or cast a spear from a wildly jolting rigid chariot would be extremely difficult. The driver and warrior would risk being tossed from the chariot as a minimum, and the warrior would not be able to aim with any sort of accuracy).
Of course, lightly built "sprung" chariots would not only be expensive, but also would not last very long due to the stresses imposed upon them. (Real chariots seem to have been disassembled and stored when not in use, and it is possible that they would be taken by wagon train closer to the battlefield, much like tanks today are carried on tank transporters for long moves). Unless the Pharaoh can charge a premium price for the ride (and perhaps the Kings of Assyria, Nubia, Mycenae and the Minoan kingdom would become fans), the expense of building and refurbishing roller coaster carts will probably bring the project to an end. Less fun loving successors will probably not bother to keep the ride running, since cart builders and slaves can be put to more productive use.
In later years, the remains of the roller coaster would be looked on as somewhat mysterious, since there would not be much memory or record of what it was used for (no crowds of peasants would be waiting at the gates to ride a Pharaonic roller coaster, it wold be reserved for royalty or the high priests), and of course there would be no carts to help decipher the mystery, unless one was disassembled and parked in a royal tomb.
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The resources are all there to create a great roller-coaster.
**Height**
This can be variable, but let's go with the largest [we see today under construction](http://www.dailymail.co.uk/news/article-2662875/Are-brave-Goliath-Six-Flags-open-worlds-tallest-steepest-fastest-wooden-roller-coaster.html) for a wooden roller coaster, and allow for a 180' drop, and speeds of 72mph.
**Loops**
Khufu may have as many loops, [such as this](https://www.youtube.com/watch?v=6s2KmjufJPc), that his heart desires. Keep in mind for your story that there may have to be more assisted ascents for the longer and faster his coaster may go.
**Maintenance**
Fortunately, a dryer climate is better for wood, but with wooden (not metal) pegs holding everything together, his engineers would do well to keep a close eye on the joints. Some support beams can be assisted by stone where there is little impact on the rider.
'Cars' will be tricky, as well, as they will be made of wood, with wooden wheels and joints. Seats can be leather stuffed with wool or any other soft material to reduce discomfort for the rider.
**Operation**
While you might have to rely on human or camel labor to draw the car upwards, a [system of pulleys](https://en.wikipedia.org/wiki/Pulley#/media/File:Polispasto4.jpg) can reduce the effort on behalf of your 'engines'. The pull on the car will have to be rope-and-hook, but could certainly be doable.
The breaking mechanism will be tricky. Maybe one thick board (not your whole car) can stick below the car and catch a long trough of water, which will slow the cars; else, you can use rolling friction and a small hill to slow them down.
**Bonus**
1. Camels and a pully-system.
2. This is highly variable, but I would anticipate 5 to 10 in single-file line; with the cars, I am confident from my experience in the Gulf that a single camel can pull this.
3. Does Khufu really care about safety? Otherwise, you can ensure wheels run in a closed wooden track, and that inspections of the whole system are undertaken frequently by his talented engineers.
4. 60 years of active service is possible with *frequent* maintenance. After that, there will be little left of your coaster within just a few years. Leather bands on the wheels, some bits might be preserved under sand, but that's it. Maybe there was a roller coaster back then...
5. I can't imagine a roller coaster that lasted 60 years (and disintegrated after that) would affect modern history. Keep in mind that Egyptians had technological sophistication that was independently re-invented later in Europe, such as scientific empiricism ([Ebers Papyrus](https://en.wikipedia.org/wiki/Ebers_Papyrus), 1550BC), which was later attributed to philosophers such as John Locke in the 1800s.
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**Khufu's Space Mountain**
Due to not having the technology to build metal rails or the time/resources to research them, the best option would be to cut the roller coaster path inside the pyramid, similar to the existing tomb paths. This way a cart with wheels on the top and bottom could be used to roll down a tube cut into the pyramid.
It is rather unlikely that a loop-the-loop could be achieved with the high-friction, unpowered carts available to Khufu at the time. The total vertical drop would be the entire height of the pyramid; 455' (139 m). The carts, powered by gravity, would be capable of making fairly hard curving-turns and could seat up to four Egyptian thrill seekers. Once reaching the bottom, the carts would need to be brought back to the top, most likely by slave labor. The uninitiated Egyptians would most likely be injured by not holding onto the cart well enough, they would have had no experience with such shifting apparent gravity. The carts would be the first to break down, likely not lasting even a year without significant maintenance. The track itself could remain for centuries. Massive changes to any industrial revolutions are unlikely, the original construction was a significant feat and it doesn't appear to have been duplicated.
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@Samuel is on the right track (ahem), but got derailed (heh) by the idea of wheels.
You don't need wheels, when you have gravity.
## Ancient Egyptian Amusement Park
Ignore some of the information on [the wikipedia page](https://en.wikipedia.org/wiki/Alpine_slide).
You can use metal runners. Yes, you're going to wear out the runners. Yes, you're going to have to hand-smooth all of that, and the runners are going to cut grooves into your stone trough over time.
The principle of the sled is that you've got a lever which raises you and your seat up - which rests on woodblocks - so only the runners are exposed on the bottom. When you lower yourself, the blocks start friction braking, since the weight is no longer only on the runners. Bronze will probably last a while. Steel, of course, would be better. You might get some nice steel from India, and/or from meteorites.
But, 30-60mph! Almost as much fun as riding fumes (but far less dangerous)!
[](https://i.stack.imgur.com/cP3GO.jpg)
Given the right conditions, you can even operate injury-free. But that relies on the users not Darwin-ing themselves. The thrill-junkies will be a problem.
Everyone hikes their way to the top (no chairlifts for the plebes), so only the kings need to be hauled to the top; probably via slave-chair. They probably also get their own lane (no waiting).
Depending on the availability of runners, it's either for everyone (who can get into the Valley of the Kings, as that was a protected enclave until the 19th century), or for royalty only.
Best bet would be to pick some other cliffs along the Nile, and create the Khufu Memorial Park. You could even end in a splash-pool in the Nile (guard against crocs). Or make a bigger dam and run water-tubes, with actual running water in them.
Wheeeeee!!!!
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Sorry, a coaster could not be made in 2570 BCE, at least not safely. There is one critical piece that cannot be recreated, the wheel bearings. All modern designs share the feature of top wheels, bottom wheels, and side wheels. Without all 3 sets of wheels, the coaster can leave the track. The bearings needed for these wheels are simply not possible without modern metals and the best metal available in 2570 BCE was bronze. Bronze is good enough for the rails, wood could be imported, but steel (or even iron) was not an option. The earliest coasters were built without the bottom wheels, and solved the flying off problem by enclosing side wheels in a channel. This does not help with the bearing failure problem though.
You cannot substitute a sleeve bearing made of bronze either as that requires high pressure lubricating oil -- the axle must ride on a sheet of pressured oil or you destroy the bearing very quickly.
I would suggest that Khufu could settle for a log fume ride, it would still have been a wonder of the world. An ice flume would not be possible given Egypt's climate, but the climate worked well for the [Russian Ice Mountains](https://en.wikipedia.org/wiki/Russian_Mountains) that were the progenitor of the wheeled coaster.
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While the Egyptians had the wheel, they did not have springs or durable metal. So a fast travelling cart would likely jump out of the track, or break the wooden wheels and become a serious accident.
Apparently, in real history the "ride" was boat trips on the Nile. It was cooler, for one thing. The rich had drink service and could watch the shores go by, the adventurous hunted crocs.
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Something like this one might be possible, even made entirely out of stone
<https://en.wikipedia.org/wiki/La_Vibora>
This coaster has more of a halfpipe than a track, a lot like a bobsled course. It has low, wheeled cars. Lot's of fun.
The keys to this would be as follows:
Show the good Pharaoh the ball bearing for the wheels. The wheels themselves could be lots of layers of leather over wood with bronze ball bearings and Bronze axles. Grease with animal fat. Wouldn't last all that long, but with the entire old Kingdom at your disposal, spares could be made in very large quantities. The cart itself is a very straightforward design. Tack wheels on the sides of a canoe and you are 90% of the way there. Just add some extra weight in a way to lower the center of gravity. All concepts Egyptian Engineers could grasp. When a cart starts to break down, just replace. The stone structure would remain for the ages.
A powered track to take riders to the top could be easily powered by an Ox driven treadmill. Carefully align everything to dimensions of Astrological significance and in 20 years, the God-King can go for a ride.
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Specifically, the gas giant [Epsilon Eridani b](https://en.wikipedia.org/wiki/Epsilon_Eridani_b), and a moon that has a mass of ≥0.25 Me. If there's no feasible way the moon could have oceans at a distance of 3.52 AU from a star that emits 0.34 times the amount of light that the sun does.
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The other answers are incorrect. There are two possible ways a moon of Epsilon Eridani b could have oceans.
One) Subsurface oceans beneath a thick shell of ice.
According to this list
[Largest lakes and seas in the solar system](https://en.wikipedia.org/wiki/List_of_largest_lakes_and_seas_in_the_Solar_System)
6 bodies in the outer solar system have global subsurface oceans of liquid water, and another 11 are suspected to. And I think there are probably more subsurface oceans in many larger Trans Neptunian Objects.
The question asked for surface oceans of liquid water, but for some types of stories, subsurface oceans might be good.
Two) Tidal interactions between the moon and its planet can cause sufficient tidal heating for liquid water oceans on the surface.
Theoretical studies of the possibiity of habitable exomoons of giant exoplanets show that the extent of tidal heating on those exomoons depends on their distance from their planets, among other factors. As a rule the closer to the planet, the greater the tidal heating on the moon.
If the moon orbits too close to the planet, the tidal heating will be enough to initate a runaway greenhouse effect, turning all the surface water into atmospheric water vapor. If the moon orbits even closer, the tidal heating will cause excesse vulcanism on the moon, making it a volcanic hell like Io.
Thus the phrase "habitable edge" for the inner limit of how close a moon can orbit to its planet while avoiding excessive tidal heating.
And it should be obvious that if the planet and moon orbit too far from their star for stellar radiation alone to warm the moon enough for liquid water, the moon could still be warm enough if it orbits outside the tidal edge but close enough for enough tidal heating for liquid water oceans.
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Epsilon Eridani B has Mass of roughly 0.63 that of Jupiter (and is therefore not a brown dwarf star due to lack of mass), and a temperature of ~150 K (−123 °C; −190 °F).
This is too cold to have liquid water, and any moons of Epsilon Eridani B would have a similar temperature, and would therefore also not have surface oceans of liquid water.
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It's too far away from the star and so cold for the surface of any ocean to be liquid.
Taking an example from the moons of Jupiter, [Europa](https://en.wikipedia.org/wiki/Europa_(moon)) in particular, the possibility of a sub-surface ocean might be explored.
Internal heat generated by tidal flexing from the interaction with the orbits of other moons, and perhaps a slightly eccentric orbit might produce sufficient equivalent-to-tectonic stresses within the crust, could enable liquid water to exist.
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Whoops, looking at the numbers, I've just realized it is kinda impossible. So nevermind!
Here's the math (I might've made an error somewhere):
$$
f=\frac{L}{4\pi d^{2}}
$$
L is the luminosity of Epsilon Eridani, which is 0.34 times that of the sun.
d is the distance between Epsilon Eridani and Epsilon Eridani b, which is 3.54 AU
So plugging in the numbers gives us
$$
\frac{0.34}{4\pi 3.52^{2}}\approx0.00218365349994
$$
The final value is the fraction of earth's solar flux, which is 1373W/m2, so if we do a simple calculation:
$$
1373\left(0.00218365349994\right)=2.99815625542
$$
The final value we get is 2.99815625542W/m2. Let me know if I got anything wrong!
Anyway, enough math, the final value (2.99815625542W/m2) is very small. Definitely not enough to raise the moon's temperature above 0C (which is the freezing point of water no matter the pressure). So this question answered itself with math!
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There were many questions in this site about slaying dragons, butchering dragons, but never one about restraining them. Poor Gyvaris managed to avoid all those fates but the last.
Gyvaris is a dragon, currently in the "service" of not St. Martha and not St. George. Having been nearly killed and unintentionally publically humiliated by, then forced to serve them, Gyvaris is unstable.
Stories of dragons razing entire cities by themselves is just unsubstantiated dwarven propaganda *(they'd blame everything from missing homework to the Armenian Genocide on dragons if they could get away with it)*. **Regardless Gyvaris' hissy fits could still range anywhere from property damage to burning children.**
That is problematic because **Gyv is supposed to be a layer of defense for George's village and that limits restrainment methods. It's certain though that you'd want to shut him down IMMEDIATELLY if things are going south.**
Dragons are roughly the same size as a horse and as intelligent as humans. Their natural weapons are their jaws, claws and a spade at the end of their tail. They're slim and athletic with enough strength to overpower a human but not bigger animals (i.e: bears). Their breath weapon is basically an explosive charge (think of thermobaric grenades), the shot limit is 5. Under normal condition, the dragon can regain 1 shot per hour.
**How could a dragon be restrained in a fast, reliable way to prevent him from damaging others or himself when throwing a tantrum?**
The tech-level is late-medieval.
Dragons can fly but we're assuming they choose not to when in a fit.
This question is about restraining dragons, not killing them, if they disobey orders.
[Answer]
**Hood.**
[](https://i.stack.imgur.com/FMSOA.jpg)
[source](https://www.bing.com/images/search?view=detailV2&ccid=rszOdvZx&id=3DCE71094104195A66AF79107F6D47BA1137B9A4&thid=OIP.rszOdvZxQ1iHX3DkazsvywHaE7&mediaurl=https%3a%2f%2ffarm7.staticflickr.com%2f6154%2f6190016374_3c3e6eb8d3_z.jpg&exph=426&expw=640&q=eagle+hood&simid=608002089243577819&selectedIndex=2&ajaxhist=0)
Lots of animals calm down when they see nothing but black. Birds of prey are the best known and probably closest to a dragon. But it works for cats (wild and domestic) and horses that I know of. I feel like I have seen nature show where captured creatures (?raccoons) have a breatheable bag put over their heads, and they become more mellow.
Your dragon has a hood, or blinders. His rider flips it on (or down). When he sees only the flat black, the stuff that was getting him riled up disappears from his perspective. It is like night came early. Night time is time to chill out. And that is what he does.
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Oh no, you can't restrain a dragon, you have to train your dragon.
Given that over the last few years there has been a significant series of documentaries made explaining in detail *How to train your dragon* I shan't go into specific detail here, but we must go over the reasons.
Like any large or dangerous animal, if untrained it can be a danger to itself and those around it. Consider large dogs for example, an untrained large dog is a significant risk, just by virtue of the damage it could do by running off with a small child being dragged along behind. No tempter tantrum, no malice, just a lack of training. One could say the same of a bull, that rope on the ring through its nose is really just a hint, if that bill threw a tantrum the rope will not make much difference at all. Hence training is critical, always positive reinforcement not punishment.
Or use an adamantium choke chain.
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>
> *"They're slim and athletic with enough strength to overpower a human but not bigger animals (i.e: bears)."*
>
>
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Cages. Bears are stronger and can't escape cages, sl your dragon would be properly constrained in one.
Also, feed him opioids so as to cause an addiction. Once the dragon is done performing whatever defense tasks here and there, he'll know to go back to his cage for his next fix.
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Data point - as comments may vanish.
You do not own a dragon - even if you captured it.
A close enough analogy is a cat.
However, do not suppose that the analogy is close enough to risk yourself to it.
A dragon tolerates you saying that you own it.
It may appear somewhat domesticated, just as a cat may.
After I stroked "my" drag... er cat for a while yesterday it turned it's head to channel my fingers into its mouth and held them between its teeth with enough not-quite-skin-piercing force to ensure that it knew I knew and I knew it knew what the relationship was. Dragons are not always as skilled as cats at determining where the warning/worse boundaries lie.
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If they choose not to fly in fits, then I could see them being knocked out by anyone who can surprise them or is fast enough. Maybe a hit to the windpipe to stop the flame breath and a hit to the noggin to knock it out. Maybe someone more daring could choke out the dragon to knock it out.
From there, the wings need to be tied and the muzzle can be tied shut to prevent fire and biting while still letting it speak a little. From there, the dragon could be restrained like any big person. Maybe with rope serving as makeshift handcuffs or maybe chains and shakles would fit the setting better.
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You could have him wear an elaborate harness with mounting points for pulleys, that extends over his wings. Wind ropes through these pulleys and all you have to do is assign some villagers to be handlers, and if things go south pull the ropes HARD. The dragon is wrapped up tight and can easily be released when he calms down.
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[Question]
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I'm designing a small two-person spaceship for use in battles in space. It is set around the year 2100.
It would be around the size of a tank (approx. 50 tons).
It would need to be fast and easy to control, as it would go up against laser weapons and heat-seeking missiles (Star Wars style).
As it would stay within 1km of its mothership, it could be regularly refuelled during the battle; it would, however, need to be compact.
Staying at around 1G, it would need to be able to fly for, say, 5 minutes.
The pilots could withstand up to 8G's.
What scientifically-accurate fuel/engine could be used on the ship?
[Answer]
**Batteries and liquid hydrogen.**
Your ship uses as its engines a quartet of electric [ion thrusters](https://en.wikipedia.org/wiki/Ion_thruster) which fire hydrogen plasma (ionized hydrogen) at a significant fraction of the speed of light. Each thruster can rotate 360 degrees, though will not fire when pointing at the ship (that is bad for the ship and occupants). Combinations of thrusters confer immense maneuverability in 3 dimensions; for example two forward and two back allow the ship to spin 180 degrees in place.
Energy conferred increases as the square of velocity and so most of the impulse is because the hydrogen gets moving so fast. Hydrogen is light and cheap. This minimizes the ships mass and maximizes maneuverability. Liquid hydrogen is a doable deal. If you want weirder scifi they could store it as exotic hydrogen metal.
I like the idea that the accelerator tubes stay short when a lot of maneuverability is necessary, to reduce angular momentum. If the ship really needs to go fast the accelerators telescope out behind the ship to increase the length over which electromagnetic acceleration can happen. Also they get hot and glow.
The thrusters can serve as weapons; a supply of radon is kept on board for that purpose because it makes a better particle beam than hydrogen. Radon dumped in as propellant can also provide a burst of speed because the mass part of mv2 increases by 3 orders of magnitude.
[Answer]
Beamed power might be of interest: since these fighters remain close to the mothership, the mothership could supply them with energy via laser or microwave beams that they converted back into electricity for use in weapons and propulsion.
This would allow your fighters to be smaller and lighter because they didn't have to lug around a power source, but it would be a lot safer than using high energy density fuel.
Of course, You'd have to have some justification for why the mother ship doesn't focus these beams to the point where they do damage to the enemy and just shoot them down directly.
Other options are the aforementioned metallic hydrogen - but beware, this us a super theoretical substance right now. We're pretty sure it exists under the tremendous pressures found inside gas giants, but there's really nothing to indicate that there's a metastable state that will allow it to keep its metallic state at lower pressures. Also, because it's got so much energy stored, it's fiendishly explosive, and because it's so dense it makes for an amazing implosion target when used in an inertial fusion reactor.
A substance that is (somewhat) less likely to blow up when you look at it funny, is Uranium Tetrabromide dissolved in water. You store this is thin tanks coated with a radiation dampener, then when you want to GOFAST you pump it into the reaction chamber where enough of the solution accumulates to start nuclear fission. You then ride the fury road to Valhalla, all shiny and chrome, upon your continuously detonating nuclear bomb.
For more details check out the Atomic Rockets website, and the Engine List pages in particular.
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1G for an hour is an astonishing amount of fuel for a space vehicle. It doesn't sound like much for an air breather, but space vehicles have to hold onto their own reaction mass.
9.8m/s^2 for 3600 seconds is 35km/s of delta-V, which is how rockets measure these capabilities. 35km/s is a *lot*. That's almost enough to escape Earth's gravity well and head into the sun (which, ironically, is 2-3x harder to reach than Pluto). Here's what we used to get the [Parker Solar Probe](https://www.nasa.gov/content/goddard/parker-solar-probe-humanity-s-first-visit-to-a-star) there:
[](https://i.stack.imgur.com/L1RPR.jpg)
The probe itself had a mass of 685kg (1,510 lbs). It took the mighty Delta-IV with an upper stage, weighing in at 733,000 kg (1,616,000 lb) to lift it there. Scaling that down to 100,000lbs, you can have a payload (pilot, weapons, life support, etc.) of around 93lbs.
Welcome to the [tyranny of the rocket equation](https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation). You have to take everything with you. This results in an exponential increase in fuel mass needed as your delta-V budget goes up linearly. If you want to fly for 24hours at 1 Gee before refueling, that's the kind of budget you need.
We can save on this by using ion thrusters rather than chemical rockets. Ion thrusters have a higher [Specific Impulse](https://en.wikipedia.org/wiki/Specific_impulse), but there's a catch. They have *very* small thrusts. The highest thrust experimental thruster to date clocks in at around 88N. That's enough to accelerate about 9kg of mass at 1G. Of course, the thruster itself is substantially more massive than 9kg.
So what you need is a sudden leap in ion thruster technology to gain several order of mangnitude of thurst-to-weight ratio. That's the direction Willik went with [his answer](https://worldbuilding.stackexchange.com/a/152017/2252), and its pretty much the best you'll be able to do. Just call them "{adjective} ion thrusters" and don't explain anything more than that.
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Of course, all that being said and done, there is a substantial frame challenge to be offered. Space combat does not work like it does in Star Wars. If you use real physics, you do not get Star Wars. Why? Well consider this. You want a craft that can pull 1G for 1 hours that hangs out 1km away from the mothership. I, as your opponent, instead build a craft that accelerates at 1G for just 17 minutes. This is *much much much* easier, so you should assume that if you can make your craft, then I can make mine (unless you plan on only taking on primitive cultures). I start a good distance away, and accelerate in a straight direction towards your ship for 17 minutes. My relative velocity with respect to your ship is now
10km/s. The time it takes for me to clear your fighter and impact your mothership is about a tenth of a second. If I'm willing to stay longer, say 1 second instead of 1/10th, then I only need to accelerate for just under 2 minutes. That's a mass-producible rocket using today's technology. I can make literally hundreds of them for the cost of one of your fighters. Any opponent versed in real-physics space flight will bombard you from so far away that your fighter will not be able to do much besides sit there.
This is why we find that most star-wars and star-trek style worlds simply invent their own technology. Trying to adapt our reality to those styles of worlds is fraught with difficulty. Better to have warp drives and inertial dampers.
[Answer]
# Nuclear Rocket is the only solution within ~100 years...
### Chemical rockets do not work
Chemical rockets do not work because of the rocket equation. You have to carry your own fuel, so you need a very high effective exhaust velocity. See this table, [here](https://en.wikipedia.org/wiki/Spacecraft_propulsion#Table_of_methods). Thrust is based on conservation of momentum ($mv$) between you and your fuel. If your $v$ is low, you need a lot of fuel to thrust; if you carry a lot of fuel, you need even more fuel to overcome the inertia of that fuel. Other answers cover the rocket equation in detail. The bottom line is, you need $v$ to be as high as possible to move.
### Electro-magnetic thrusters do not work
Other answers discuss the possibility of an ion engine. There are many variants using various electrostatic or magnetic (or electro-magnetic, or magneto-plasma-dynamic, etc) principle to fire high energy particles out as your source of thrust. Where the impulse of a chemical rocket might be 200 s; an electric thruster can easily hit 2,000 s, maybe as high as 20,000 s.
Unfortunately, the drawback here is the ratio of thrust to power is very high. You need to generate electric power, and then use that electricity to generate an electrostatic or magnetic (or both) field. Both these conversion processes have significant losses. For example, the VASMIR--possibly the most advanced magnetic thruster created thus far--as a power ratio of about 40 kW/N. An F-15 (25 tons, about the size you are talking about) generates about 140 kN at max power; that requires 5.6 GW of electric power; about the energy output of the [world's largest coal and nuclear plants](https://en.wikipedia.org/wiki/List_of_largest_power_stations). Obviously, those plants aren't going to fit on a fighter.
### Which leaves a nuclear rocket
The only working idea is to use a nuclear rocket. This uses a nuclear reaction and magnetic field to blow fission or fusion products out the back of the rocket. The concept works best with [fission fragments](https://en.wikipedia.org/wiki/Fission-fragment_rocket), as these have high mass and a strong positive electrical charge (electrons are stripped into plasma; fusion fragments are thus atomic nuclei).
While these rockets do have a relatively high power demand for maintaining a magnetic field, the impulse of the particles generated is much higher; as much as 1,000,000 s; with fission fragments ejecting at greater than 0.01$c$. Thus, the power to thrust ratio is much better than with electromagnetic thrusters.
# ... but not with people onboard
So we have the perfect engine, capable of outstanding thrust with a minimal power source. Unfortunately, you do have the issue of the nuclear bomb going off right behind the cockpit. While magnetic fields can reasonably contain charged particles, they cannot do anything about gamma radiation or neutrons, both of which will be produced in abundance.
Unfortunately for any squishy biological, gammas and neutrons will quickly extinguish any life forms within ~20 meters of such a powerful reaction. If you want these fighters, they will have to be piloted by AI, or remote operators.
Or, instead of fighters, they could be torpedos, which is the hard-sci-fi practical way of doing it...
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I am assuming you are not proposing some unknown method of thrust. Are you sure you need to thrust at 1 g for an hour? The [rocket equation](https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation) has something to say about this.
[](https://i.stack.imgur.com/sWlAj.png)
The rocket equation tells you how much change in velocity you can get from a given rocket for a given change in mass. The rocket design gives you the specific impulse (that's the $I\_{sp}$ factor). Then by pushing mass out the back you make the rocket go forward. The mass you lose as reaction mass means you start with mass $m\_f$, and finish with mass $m\_o$. And $g\_o$ is one Earth gravity.
If you use the specific impulse of a [space shuttle solid booster](https://en.wikipedia.org/wiki/Specific_impulse#Examples) (about 250 seconds), then the rocket equation tells you that to accelerate for 1 hour at 1 g requires about 1.7 million times the mass in fuel as you have in ship.
If you use liquid oxygen-liquid hydrogen you can get a specific impulse of about 450 seconds, which means you need about 3000 times the mass of fuel as ship. Still seems unreasonable.
If you could get an ion thruster (specific impulse about 3000 seconds) to thrust you at 1 g, then you'd need about 1.3 times mass fuel as ship. But ion thrusters produce very small thrusts. And a ship with a fuel tank larger than it is still seems pretty clunky.
In other words, maybe you don't need to be thrusting for that entire hour? It is space, after all. If you don't thrust you just "follow your nose" in whatever orbit you happen to be in. If all you really need is a few minutes of maneuvering during actual combat then liquid oxygen-liquid hydrogen might cover it.
[Answer]
As discussed on [this projectrho.com](http://www.projectrho.com/public_html/rocket/enginelist.php) page, for near-future rocket technologies there tends to be a tradeoff between thrust (which gives the force on the rocket, so you can divide by the rocket's mass at any given moment to get its acceleration) and specific impulse (which is just the effective exhaust velocity divided by an acceleration of 1 G, as mentioned [here](https://en.wikipedia.org/wiki/Specific_impulse#Rocketry)). According to the [Tsiolkovsky rocket equation](https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation), if you want to know the total change in velocity $\Delta v$ a rocket can achieve if it fires continuously in a straight line until it burns all its fuel, this doesn't actually depend on the thrust, only on the effective exhaust velocity $v\_e$ (or specific impulse $I\_{sp}$) and on the ratio $\frac{m\_0}{m\_f}$ between the initial mass $m\_0$ of the rocket including fuel at the beginning of the acceleration and the final mass $m\_f$ remaining once all the fuel has been burned (i.e. the payload mass).
The Tsiolkovsky rocket equation is $\Delta v = v\_e \ln \frac{m\_0}{m\_f}$, where $\ln$ is the [natural logarithm function](https://en.wikipedia.org/wiki/Natural_logarithm), and if you divide both sides by $v\_e$ and take $e$ to the power of each side (see [e (mathematical constant)](https://en.wikipedia.org/wiki/E_(mathematical_constant))), you get the equation $\frac{m\_0}{m\_f} = e^{\frac{\Delta v}{v\_e}}$ (the natural logarithm function $\ln (x)$ is the inverse of $e^x$, so $e^{\ln \frac{m\_0}{m\_f}} = \frac{m\_0}{m\_f}$). So if you know the effective exhaust velocity of a type of rocket and the desired change in velocity $\Delta v$, this will tell you how many kg of fuel you're going to need for every kg of payload mass.
A 9.8 m/s^2 acceleration for an hour would give a change in velocity $\Delta v$ of about 36000 m/s, so for example if the effective exhaust velocity $v\_e$ was 4400 m/s, about that of the [space shuttle main engine](https://en.wikipedia.org/wiki/RS-25), then you'd have an initial mass to payload mass ratio of $e^{\frac{\Delta v}{v\_e}} = e^{\frac{36000}{4400}} = 3575$. That means if the initial mass when fully fueled is 50 metric tons or 50000 kg, the final mass when the fuel is burned would only be 50000 kg/3575 = 14 kg! No real or proposed chemical rocket has an effective exhaust velocity much greater than this, so you'll need to go with some other form of propulsion.
Others have suggested an [ion drive](https://en.wikipedia.org/wiki/Ion_thruster), but while these do have a much higher exhaust velocity, the problem as mentioned on [this NASA page](https://www.nasa.gov/centers/glenn/technology/Ion_Propulsion1.html) is that "The trade-off for the high top speeds of ion thrusters is low thrust (or low acceleration)." If you scroll down to the "Drive Table" section of the [projectrho.com page](http://www.projectrho.com/public_html/rocket/enginelist.php) I linked earlier, it has a large variety of real and proposed future rocket designs, including many possible types of ion drives. As [the wiki page](https://en.wikipedia.org/wiki/Ion_thruster#General_working_principle) mentions, 'Ion thrusters are categorized as either electrostatic or electromagnetic', so if you look in the 'Code' column of the projectrho table, ion drives can be identified by the code "ESTAT" or "EMAG". And the final column of the projectrho table is T/W, or the thrust-to-weight ratio for each type of engine, i.e. the thrust it produces divided by its weight in standard earth gravity (mass times 1 G), not including fuel mass or any additional structural mass like the payload. So, a T/W value of 1 would mean that if such a rocket was burning the last of its fuel, and was in space with no other mass attached, it would be accelerating at 1 G (as mentioned in the ['Rockets' section of the wiki page on the thrust-to-weight ratio](https://en.wikipedia.org/wiki/Thrust-to-weight_ratio#Rockets), 'The thrust-to-weight ratio of an engine exceeds that of the whole launch vehicle but is nonetheless useful because it determines the maximum acceleration that any vehicle using that engine could theoretically achieve with minimum propellant and structure attached.') And if you look at the table, the T/W for all the engines labelled "ESTAT" or "EMAG" are much smaller than 1, meaning those ion drives couldn't accelerate at anything close to 1 G.
Your best bet for a near-future technology might be a [nuclear thermal rocket](https://en.wikipedia.org/wiki/Nuclear_thermal_rocket), where the working fluid is heated by nuclear reactions rather than chemical ones before being expelled out the nozzle to create thrust. These types of rockets have codes beginning with "NTR" in the table. They would have the advantage of producing thrust in about the same range as a chemical rocket, but with significantly higher exhaust velocity, so less fuel needed to achieve a given $\Delta v$. And the technology isn't too advanced to be plausible in 2100, nuclear-thermal rockets were studied by NASA in the sixties, probably the main reason they never went forward was the danger associated with radioactive exhaust or the possibility of exploding in the atmosphere, but there would be much less danger if they could be constructed in space. One design that was studied was named [DUMBO](https://beyondnerva.com/2019/02/26/dumbo-americas-first-forgotten-ntr/), the projectrho section on it [here](http://www.projectrho.com/public_html/rocket/enginelist2.php#ntrsoliddumbo) links to a NASA document [here](https://web.archive.org/web/20120204044749/http://www.dunnspace.com/00339489.pdf) that gives more details. The table lists several variants of DUMBO, with DUMBO (H) having the highest exhaust velocity of 16,000 m/s. So, for a $\Delta v$ of 36000 m/s, you'd have an initial mass to payload mass ratio of $e^{\frac{\Delta v}{v\_e}} = e^{\frac{36000}{16000}} = 9.5$. So if the initial mass when fully fueled is 50 metric tons, the final mass when all the fuel is burned can be about 5.3 metric tons. The engine itself is said to have a mass of about 5000 kg = 5 metric tons, so this doesn't leave a lot of mass for pilots and cockpit, but you could always boost the total mass to say 70 metric tons, in which case the final mass when the fuel is burned would be 7.4 metric tons so you'd have 2.4 metric tons left over after accounting for the engine mass. And this engine is said to have a thrust of 3500000 Newtons = 3500000 kg\*m/s^2, so even with a fully fuelled mass of 70 metric tons = 70000 kg, the acceleration could be as high as 3500000/70000 = 50 m/s^2 or about 5.1 G, and as fuel is burned and the mass goes down, the maximum acceleration will increase.
One thing I'm not sure about here is that DUMBO (H) on the projectrho page presumably refers to a DUMBO drive using monatomic hydrogen as the working fluid (distinct from DUMBO (H2) elsewhere in the table), and it lists this with the code "NTR SOLID" meaning it's using nuclear fuel in solid form inside the reactor (as distinct from nuclear thermal drive designs using liquid or gaseous nuclear fuel, discussed [here](https://beyondnerva.com/nuclear-thermal-propulsion/)), but the "Propellants: Advantages and challenges" section on [this page](https://beyondnerva.com/nuclear-thermal-propulsion/solid-core-ntr/) claims that "Unfortunately, solid fuel cannot reach the temperatures required to dissociate H2 into monatomic hydrogen." So it could be that the projectrho guy was incorrectly extrapolating the DUMBO design to see how it would perform with monatomic hydrogen even though it's not actually capable of using it. None of the other nuclear thermal rockets on the table seem to have combos of exhaust velocity and T/W that would work as well, but you could always modify the parameters of your ship to something that would still exceed the capabilities of chemical rockets but not need to accelerate for quite as long, say a ship capable of 1 G acceleration for 30 minutes for a $\Delta v$ of 17640 m/s. That way the DUMBO (H2) which has an effective exhaust velocity of 8093 m/s would be able to do it, since the initial mass to payload mass ratio would be about the same as in my previous calculation, $e^{\frac{\Delta v}{v\_e}} = e^{\frac{17640}{8093}} = 8.8$ (meaning that if the initial mass when fueled is 70 metric tons then the final mass when the fuel is spent is about 70/8.8 = 8 metric tons) and the mass of the rocket engine is still 5 metric tons (leaving 3 extra tons for crew capsule and other non-engine structure that remain when fuel is depleted) and the thrust is exactly the same as in the previous calculation so it can still do about 5 G of acceleration when fully fueled.
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[Question]
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Setting is [20 minutes into future](https://tvtropes.org/pmwiki/pmwiki.php/Main/TwentyMinutesIntoTheFuture) - everything is as we know it, or as we can reasonably predict, except the zero-tau capsules.
Capsule is a thin mesh of Unobtanium connected to a portable Handwavium reactor. When turned on, time inside does not flow. Details "by the numbers":
1. It is unclear if time inside actually stopped or is just extremely slowed down. A [insert reasonable time here]-long experiment did not show any measurable time inside (in other words, you may adjust this).
2. Starting field up and shutting it down can be instantaneous, or take as long as 10 seconds during which time inside slows down or speeds up.
3. Field border is sharp, around [1ℓP](https://en.wikipedia.org/wiki/Planck_length). We put it in the middle of metal plates that are casing for capsule, to prevent anything from interacting directly with such border (or in near-vacuum between plates, if interactions with metal would be a problem - again this is adjustable).
4. Unobtanium mesh is supposed to be something that creates the field, but has no other uses or effects - it does not shield anything from anything, does not get old, nothing. Thus, it shouldn't matter if it's in or out. Probably out, because getting it destroyed would be a good story element, but that's something for another question. Similarly with Handwavium reactor. *Please ignore them where possible, their only meaningful effect should be existence of the zero-tau field.*
That way, trip to Mars can be as short as [30 seconds](https://en.wikipedia.org/wiki/Thirty_Seconds_to_Mars), from the passenger point of view.
The problem is: **How to safely exit?**
Metal walls of the capsule can stop anything bigger than hydrogen atoms, and slow down other things. But that is still around [seven months](https://www.mars-one.com/faq/mission-to-mars/how-long-does-it-take-to-travel-to-mars) of cosmic radiation, atoms leaking in thorough the seal etc, released in a very, very short time. Sudden gravity change would not help, and probably there are things that I haven't thought of, too.
So, how would we make it safe for our travelers? I want them to survive and I do not want any neural or perception damages. Other than that I can live with, as long as it heals, at least in early stages when we are only setting up Mars operations. We need to get passengers healthy when we go to commercial flights, but if it is too difficult, it can wait.
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Your zero-tau capsules are the ideal solution for their own problem:
You state that all radiation and particles that hit an active capsule are slowed down and released in a burst when the capsule is shut off. That means not only is the inside shielded while the capsule is active, but anything *behind* the capsule as well. These capsules are now a perfect shield that can stop even neutrinos or gamma radiation.
So, surround each passenger-capsule on all sides with other capsules, that are empty or contain cargo; then no radiation can hit the capsules in the middle. Just make sure to take the outer capsules far away before switching them of.
Or better yet: surround your whole spaceship with shield capsules. Perhaps multiple layers, in case anything goes wrong.
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Who says you have to have the field in unbroken operation for the whole trip?
Sensors near the "event horizon" monitor the exposure of the capsule to external radiation. When a pre-set safety threshold is approached, the capsule switches off for a small amount of time (whatever the minimum cycle time for the field - power off and back on - is, plus a small delay to allow the passenger to properly absorb/emit/adjust to the radiation), allowing the particles to strike the occupant while they are still at a safe level, and allowing gravity (and other fields) to adjust in smaller increments.
This might increase the length of the trip from the occupant's perspective, but as the shielding gets better, these interruptions can be reduced, perhaps to the point that you only need five or ten per trip, each lasting 20 seconds or so (10 second spin-down and 10 second spin-up in your extreme case). Even with modern day shielding the number of cycles would probably only be on the order of 5 or so a day, making a 300 day trip take 100 minutes from the passenger's point of view. Rounding, we can call it two hours, and the best thing to do would be to render the passenger unconscious for the journey anyway, so that two hours would be a pleasant nap.
If the cycle time was near instant (the lower bound of your power on/off range), then a conscious passenger simply gets a time lapse view of the trip lasting a few dozen seconds, which could be seen as a feature.
In either case, some form of anti-radiation treatment and
a shielded suit would be recommended to shorten the duration needed in real-time to adjust to the radiation dump.
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I'd go with "time slows down" interpretation.
If radiation particle hits the capsule, it is slowed down at its boundary, and will be released once the field is turned off.
This obviously creates a problem as passenger will be bombarded by all the particles accumulated during their voyage.
I would recommend **shielding the capsule from radiation** and light during the voyage. Space stations are shielded anyway, and while capsule will require more shielding, there is also smaller area to shield. Or you can keep large number of capsules in a vault (less surface area than individual capsules).
Gravity change is inevitable, but effect is just a (near-)fall from standing position. Can't be that bad.
I hope you realize passenger cannot "exit" the capsule on their own accord. Somebody (or something) would have to shut down the field generator.
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The world is flooded and some people have survived and managed to build small towns and even massive cities on the ocean that now covers the world. Is this possible hypothetically? How much of the world's population would be left after such an event?
Notes:
* the whole world (with the exception of a few mountain peaks) has been flooded
* this occurred over the period of let's say 5 years (or so)
* underwater cities are acceptable and would be interesting to explore but I am mainly interested in cities/towns on top of the water
[Answer]
### How much is it flooded?
A Noah-style flood went over the highest mountains. Ignoring the scientific plausibility (which is easy-enough to do when you have either religion or a science fiction/fantasy author involved), this is a **LOT** of water. A [flood of a couple hundred feet](https://www.nationalgeographic.com/magazine/2013/09/rising-seas-ice-melt-new-shoreline-maps/?user.testname=none) is enough to do a lot of damage, but is not nearly as bad (as explained below) as a Noah-style flood. This is essentially a Noah-style flood, whether the tops of a few mountains are accessible (which is better than nothing) or not.
According to [the Wikipedia list of the highest mountains on Earth](https://en.wikipedia.org/wiki/List_of_highest_mountains_on_Earth), there are 108 > 23,000 feet. That is more than "a few" but is good enough to work with. 23,000 feet/5 years ~ **12 feet per day** of rise in sea level. That is a **LOT**. Assuming we have little additional warning, that means coastal cities have problems **within a few days**.
So let's assume, for the moment, that there is a little bit of warning, just to give some people time to stockpile supplies and quickly put together a few ships. *But not decades like my original answer.*
### Underwater? NOT!
Underwater cities won't work without a huge amount of time to prepare. Water pressure increases by 1 atmosphere every 34 feet. It is possible to live at the natural pressure a few hundred feet below the surface, with enough preparation - and being extremely careful (and slow moving) coming back up. But with only the tops of the highest mountains above water, there will be relatively little land **near** the surface to build on. That means taking existing cities and enclosing them to be livable at a normal pressure. That is not too hard for 2 or 3 atmospheres. The highest cities are currently ~ 16,000 feet above sea level. 23,000 - 16,000 = 7,000 feet. 7,000/34 = 205 atmospheres. **Not going to happen**. So that limits any practical survival to the surface of the ocean.
### Start with big ships
If you start with an US aircraft carrier (which has been used in many science fiction novels that I have read) then you have a nice big platform for building on and a nuclear power plant to supply power for a while.
If you start with a cruise ship then you have living quarters for thousands of people with all the amenities.
Take either (or both) of these and link up plenty of smaller ships, boats, rafts, etc. and you can safely house thousands of people. Add a hospital ship and you have medical taken care of, at least for a little while.
Container ships can be a huge help. They aren't great for living quarters, but a ship with thousands of 40-foot containers can hold enough supplies - food, medicine, clothing, etc. - to help people survive for a while. But they won't last forever.
### Problem # 1 - Fuel
Fuel is a **BIG** problem. If you have a global flood, you can't drill for oil, dig for coal - and even if you can, a refinery takes above-water facilities that you simply don't have. Solar energy isn't nearly enough because you don't have large areas for solar panels or other collectors - in fact, you are likely building up, not out, in general - look at a typical cruise ship for an example.
Nuclear power from your aircraft carriers will help for few years, but it is limited in both time & capacity.
~~If there is enough planning from the nuclear-capable countries - e.g., US, Russia, France, Japan - then you can build a bunch of naval reactors (i.e., like the US aircraft carriers & submarines use) and mine/process as much uranium as possible to, hopefully, provide power for a group of large ships for several decades. If not, then~~ Fuel will be a **big** problem. While it may be possible to extract uranium or thorium from seawater and use that to power your floating cities, setting up a floating system to do all of that will take time to develop & test that you just don't have.
### Problem # 2: Food
I hope everyone likes fish & seaweed. Every little boat becomes a fishing boat. Every day they spread out to the surrounding area and throw out their nets and collect what they can. At the end of the day they head back to the mother ship and have fresh fish for dinner. Everything else can be stockpiled but really won't last long. A fish/seaweed diet is likely to be low in a number of vital vitamins and minerals - think Vitamin C/scurvy - so a stockpile of key vitamins and other nutrients will be critical.
Greenhouses, green roofs, etc. can help some by providing a place to grow fruits & vegetables, but only the top level of your ships will work for that, and doing so is not compatible with covering the top of everything with solar cells to produce electricity - some tough tradeoffs will be needed.
### Problem # 3: Security
Pirates will be everywhere. Only the largest countries or the largest private organizations will have self-sufficient (though all time-limited) "cities". Plenty of people will grab their guns and their boats and when they get hungry...watch out. A destroyer equipped for battle can easily stop enemy boats. An aircraft carrier or cruise ship teeming with refugees has a harder time, plus the big guns will run out of ammunition before the pirates do. No home base to call for support.
### Problem # 4: Everything Else!
Supplies of **everything** will be limited. No factories producing clothing and electronics in China. No factories producing medicine in the US. Unlike many other global disaster scenarios, no scavenging of supplies from abandoned cities.
### End result - doomed!
Too many variables to say for sure, but my guess is that:
* Largest "cities", on the order of 10,000 - 20,000 people - decimated within 10 years due to lack of fuel, food and supplies.
* Smaller "towns", on the order of 100 - 1,000 people - most will not last long at all, but some (private "towns" funded by billionaires) will be well planned, well stocked and last for decades if disease doesn't kill them off.
* Small groups - pirates, families, etc. - < 100 people - will have big problems surviving more than a few years due to lack of infrastructure (medical support, mechanical repairs, etc.)
In short, **doomed**.
[Answer]
## You have to become a "space faring" civilization.
I don't mean that you have to build spaceships and escape the planet. Instead, you have to be able to develop the same technologies required to establish long-term colonies on the moon, mars or to build interstellar [generational ships](https://en.wikipedia.org/wiki/Generation_ship). (That's why I placed "space faring" in quotes).
Basically, all the problems mentioned in [manassehkatz's response](https://worldbuilding.stackexchange.com/a/128096/56286) can only be solved if your civilization has already mastered (or has come close to mastering) the technological hurdles required to survive in harsh, enclosed, and limited-resource environments. This translates to developing efficient means of food production (e.g. hydroponics) and waste recycling. Reliance on 3D printing for nearly all manufacturing, and energy would have to be harvested from renewable means in the long run (solar, wind, tidal forces). This, in turn, would help stabilize your society and minimize the need for criminal enterprises such as piracy.
Acquiring raw materials would be harder, so either proper preparations were made before the cataclysm and/or means were devised to "mine" materials from flooded cities (as in, demolish a skyscraper or large building and extract its steel and other rare materials). The last item to watch for is population control: limiting births to two per family would be sufficient to keep a population stable long term.
Ironically, if such a civilization already has such technology available, they are most likely well underway in establishing off-world lunar, martian or martian-like outposts. These outposts would likely be placed in a situation where they'd have to try to find ways to help the planet's survivors.
[Answer]
**It could happen.**
People have speculated on floating cities for a very long time. With clean energy tech it becomes more likely. This Blue Frontiers project is the most recent incarnation and apparently enough people believe it can happen that it is underway.
<https://www.businessinsider.com/floating-city-plans-seasteading-institute-peter-thiel-blue-frontiers-2017-12#the-team-wants-to-grow-much-of-its-food-through-aquaculture-which-involves-breeding-plants-and-fish-in-water-7>
[](https://i.stack.imgur.com/9DiDV.jpg)
Issues:
1: Food. This would be done thru aquaculture and some terrestrial plants (e.g. citrus, garlic) in greenhouses.
2. Energy: Solar, wind, wave power (this would require a tether to the bottom as the city will move with the waves). Conductive metals will be in short supply but you can make conductive materials out of charcoal which can be made from bone or seaweed.
3. Stuff that floats. This warrants some thinking. Nothing lasts long at sea. Plastic and metals will degrade. Wood will rot. There will need to be some way to make durable floats to keep the city up. Glass might be a possibility - one would need to dredge or dive for sand but one can make glass floats with low tech and they are durable.
[](https://i.stack.imgur.com/Fse2G.jpg)
<http://www.glassfloatjunkie.com/myfloatpics.html>
I chose the one with the barnacle to show how long it has been in the water.
4. I am not worried about raiders. There will not be many people. Small communities police themselves. Individuals on their own will be no match for the well fed citizens of the floating city. Within a few decades no-one will have any tech advantages.
5. I am worried about inbreeding over the long term. Hopefully there are other similar settlements elsewhere and there can be some kind of exchange - useful for other reasons as well.
[Answer]
The biggest problem you'd be looking at are sea storms. If one hits one of these floating islands, you can expect some damage depending on the system you use, not to mention the loss of plant, human, and animal life. That said, if we could ignore that risk? Let's see...
First, we need to consider how the towns will be built.
1. Cities built on ships
2. Cities built on rafts
3. Cities built in enclosed environments
I'll try to give a detailed breakdown of each of these so you can see different ideas of how to work this story's angle.
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> 1. Cities built on ships
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> * Overcrowding: If a city is built on a ship, you have a limited amount of space to work with. From my research, the largest cruise ship ever capped out at less than 4,400 passenger capacity. Nimitz-Class Aircraft Carriers hold 6,000 personnel. Let's say your ships were capable of, on average, holding an upwards of 5,000 passengers while still being reasonably functional for other needs. The fact there is a definitively finite amount of space means your cities will deal with overcrowding quickly. You can probably assume the ships could handle a cap of 10,000 people, but that'd likely mean that all the city was used for was holding people: minimal-to-no food, plants, animals, or supplies. These cities would be completely reliant on ships carrying valuable resources in order to survive once they've reached that 10K capacity. If we assume an annual population growth rate of 1% (which is lower than that of the world's annual growth rate now) and a starting passenger count of 1,000, the ships would reach overcrowding (10K+ passengers) within 232 years. If the starting passenger count is 2,000, overcrowding would occur in as little 162 years. If the starting passenger count is 5,000, it occurs in as little as 70 years. This essentially means, if you want a city to survive for a longer length of time, you'd need to start with a smaller population size. The smaller the initial population, though, the sooner people would be forced to in-breed for a continued population. The larger the initial population for the close, confined space, the faster disease will spread and the more people who will be killed by sickness. Additionally, the more people there are, the more resources will be needed and consumed.
> * Sickness and Injury: As said earlier, the more people there are, the easier sickness can spread. If one person catches a contagious disease, then you can expect many people to get sick with it as well. Disease can cause multiple problems such as a drain on resources, a need for medicine, and potentially death. As for injuries, there'd need to be at least two competent doctor and 3 nurses or medics on every ship. If someone gets hurt, the nurses and medics should see the injured person first and try to resolve the issue themselves, freeing up the doctors for surgeries and more serious injuries. The nurses and medics should also constantly be trained by the doctors so that they can become doctors in case either of the first doctors die and they should be training the next generation to become medics to fill their spots as well. This allows for there to be a constant cycle of competent practitioners on-board the ship at any time to help keep people safe and alive. If the limited number of doctors die, though, then that means the city is as good as dead if the nurses/medics aren't trained enough to make up for the lack of doctors. Finally, venereal diseases would have to be heavily screened. In our world, venereal diseases are an inconvenience for most, but usually don't make for a problem for greater society, especially when most can be cured with medicine. If we assume these ships have a limited amount of space for supplies, it's not like they could afford to waste space on supplies for venereal diseases. If you have a venereal disease, you wouldn't be allowed to board the ships in the first place; the passengers can't afford to risk letting diseases like HIV/AIDS, gonorrhea, or syphilis spread. If these people do board ships, it'd likely be ships that are specifically designed exclusively for those who are infected with venereal diseases and those who want to go with them (such as family and loved ones). These ships would likely be split into two types: Curable and Incurable. The curable ships would have treatments available to cure the diseases ailing the passengers, allowing them to proceed to happy and healthy lives. The Incurable ships would be stocked with treatments to reduce the suffering of those infected, but would ultimately be an effort to protect everybody else.
> * In-Breeding: This is trickier to avoid. The population size is limited by the ship size. The larger the ship, the more people and resources it can hold; however, the more resources the ship has, the fewer people it can hold. The lower the population, the greater likelihood in-breeding and the associated side effects will occur in time. According to [this](https://www.popularmechanics.com/space/deep-space/a10369/how-many-people-does-it-take-to-colonize-another-star-system-16654747/), any population lower than 10,000 poses a serious risk within the first 200 years, meaning a ship city will already be off to a bad start if they can't get new genetic diversity within each generation. A starting population of 2000 will result in these problems starting within 100 years. A starting population of 500 will result in in-breeding as an issue almost immediately (like 35 years or so). It's not that I am saying the consequences will be immediately apparent, but it will be a start to the process. I have a solution to this, but this problem is directly tied to the next point, so I'll put the solution there.
> * Resources: Just as in-breeding is difficult to avoid, resource draining will be a hard problem to avoid. **First, let's talk food.** Fortunately, the world is all water. This means that there's going to be one ready source of food: fish. Anyone with allergies to seafood, however, will be in for a bad time, because fish would be a necessary staple to survive. While fruits and vegetables may be available, along with other sources of meat, they can't be relied on as a sole source of food for any member of a ship's population. If anything, they'd only be useful as a side dish or herbal medicine, maybe as a meal for the days when no fish are caught. To increase the amount of edible plant life available, a large garden can be put on the top decks of the ship or if appropriate synthetic sunlight lamps are available, can be placed in a lower deck of the ship. Additionally, underwater farming of seaweed and kelps can be used as a means to avoid needing to tap into the on-deck reserves. **As for water,** there's plenty available, but it's all undrinkable as is. The ship would need to have multiple pumps filtering seawater converting it into usable drinking, bathing, and other general uses. (Technically you can use it, but it's not safe to use it often.) **Then we have fuel issues.** Unless you intend on setting up oars, sails, and other means of propulsion, once the ship runs out of fuel, it will be stuck in place, helpless to the tides. Honestly, with the size and weight of these ships, anything less than an engine probably won't be enough to move the ships, meaning a cruise liner probably wouldn't be a possibility anyways. You can probably say the ship has some sort of super-advanced solar-powered, wind-powered, and/or will-powered fuel source so that this is less of an issue, but if you want realism, a ship that is actively sailing may be able to last up to two weeks at best, but you may be able to stretch that to a few months if the ship rarely sails anywhere. If you have the engines running on an alternative fuel source, the ship can sail as long as the engines are maintained, needing breaks to "refuel" at a reasonable schedule. **Then, you have issues with crafting resources.** Unlike on land, there's nowhere to mine ores, farm trees, or grow large amounts of farm animals like sheep for wool, cows for milk, and so on. You would need to have all your resources either on-board or on another ship you can regularly meet with to restock. If you don't have a way of restocking, you can expect the ramifications to hit sooner rather than later. You could possibly turn kelp into paper for writing, but that'd be difficult and wouldn't preserve well. You could always reforge broken tools, but that'd require a capable craftsman and access to appropriate heat sources and fuel. Even if you were able to come up with temporary substitutes and solutions, the internet would be gone, so you'd have to relay everything by writing and teaching. You can't rely on being able to always show exactly what to do for the steps because it'd be wasteful to do so if it isn't immediately necessary. **Finally, you have medicines and hard to produce resources.** If something can't be produced with whats on-hand, you have to hope you can get it in trade with other ships or that you can live without it. For example, if one ship has plenty of medicines, bacterial cultures, and plants, it'd be reasonable to assume they'd be fine in terms of medicine. A ship that has run out of all of that, may be consistent of people who only survive due to hardiness, but if someone gets sick, they're as good as dead. A ship that is full of metal, wires, and electronics may develop its own culture around that maintaining heavy similarity to our current world, but they may have reliance on their technology to keep themselves safe and lack the ability to do anything without their machines once that supply of resources runs out. A ship full of paper may develop an art and writing culture, while trying to use that as a means to trade for food and other resources they may have to do without. A ship full of fabrics may develop a fashion culture where they trade clothing to the other ships. The ships would have their own cultures that require constant trade or conquest in order to maintain. **On to the solution to this and in-breeding!** Each ship would have its own culture by nature of what is on-board. Trade between ships would become a frequent need in order to survive, and would likely take place on aircraft carriers that have been redesigned to be basic "resource hubs" or "marketplaces" where different cities could meet and propose large amounts of trade, with the Hubs taking a small cut for facilitating these trades. Once a year, a festival would occur where the cities in the area would meet, party, and trade aspects of their cultures while allowing people to move from one city to another if they so wish. Every 25 years, the 10% of each city that had been there the longest would be required to move to a different one of the cities that arrived for the Quarter-Centennial celebration in order to maintain a balanced variety of genetic diversity and to reduce the risk of in-breeding. Additionally, since the cities that will be near a given hub will be different as time goes on, a city that had recently lost a large number of citizens due to disease or disaster could get a large in-flux of new passengers to help run things. This also means any skills and trades a given passenger has will now be available to the new ship. If the doctors of a ship died, one of the doctors from another ship can move to that city to take over that practice and teach the next generation. If there are no mechanics, technicians, or artisans, new ones can come over and get to work. It'd be a superculture of cooperation to ensure the betterment of every member city's own culture. Even at a cynical level, every member of society can be given an associated value and when they apply to move cities or when their time is up and they have to move cities, they can be traded between cities based on their value in exchange for new citizens and for resources. This way, no city feels like they are being forced to lose something because they can always get something in exchange. For example, if it's time for the city's most skilled fisherman to leave, they can trade him for medicines or a person (or possibly people) with a skill the city desperately needs. You could even play with this idea by bringing up the ramifications of "what if the leaders lie about how long a person has lived in the city to maintain control and "ownership" of them. After all, this system in a way isn't that different from slavery, where it's the city that owns the people as opposed to an individual master. You can also play with different political systems for the different cities as a result.
> * **The biggest issue these kinds of ship cities would have is** 1) fuel running out making them dead in the water, 2) a limited amount of resources before running out, and 3) not being able to do anything if they end up in an area with no other ships. These cities would be heavily dependent on one another, but would also have to be able to act on their own to find new areas and access more resources. While it's not impossible for every ship-city to exist in one small area, it's also not a good idea for them to be that close in case the navigators mess up and crash into another ship. Also, if a storm does hit, they'd all be sunk... either figuratively or literally. Finally, there'd be limits to how much plant life can be grown and how many animals can be kept on-board for ranching purposes.
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> 2. Cities built on rafts
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> Fortunately, a city built on a raft has access to a more traditional town-layout. The thing is, it would have many of the same limits and problems as a Ship-City. Overcrowding, In-Breeding, and Resource depletion would all be the exact same points. Fortunately, fuel would be a non-issue, so that's one resource not to worry about. If built large enough, these raft cities could even be built with large farms and ranches so that those resources will never run out. Any material resources like wood, stone, metal, and so forth would still be subject to depletion. If anything ever happens to the water purification system, the town/city would be even more doomed than with a ship city. Finally, if a storm were to hit, the devastation would be even worse as a ship city can have everyone get inside and at least better prepare for it. With a raft city, the plants and animals would most certainly be killed, the city would likely break apart, and the housing would likely be destroyed... all with no way to rebuild. Resource exchange between cities would need to send boats between locations, and people would need to be able to freely move between cities to ensure genetic diversity.
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> 3. Cities built in enclosed environments
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> Picture a large glass bubble. Inside the bubble, the bottom 15-20% of it is full of dirt. On the dirt there are trees, animals, houses, and people. The outside of the sphere has various machines on all sides, bobbing in and out of the water as the outer layer turns, the entire facility a giant gyroscope. Water gets pumped in by pumps for keeping the soil hydrated and for providing water to the residents. Periodically, the machines on the side activate to keep the environment still long enough for the top to open and let fresh air in. Occasionally, people get into those machines and sail off to get resources from other bubbles. In a way, this is basically an "underwater dome" meets "floating city" idea. If you weren't insistent on the city floating, I'd have just suggested an underwater dome ideas with ventilation shafts leading to the surface, but this was the closest I could modify the idea into. It'd have many of the same benefits and detriments of the ship and the raft ideas, but would come with the added bonus of being more resistant to the effects of waves and storms (in theory) as the gyroscope would keep everything upright, with the bouncing of it in the water being the biggest hazard as it would likely bob until the external stabilizers kicked in.
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Honestly, these are all thoughts of how the cities could exist. Frankly, all three of them would need to be used in conjunction so that there'd be more potential for survival. Would it last long? Not at all. The cultures would die off within a few hundred years at most due to war, disease, excessive in-breeding, and various other issues. Essentially, humanity would need to grow gills in order to survive indefinitely, but we'd (in turn) lose most, if not all, of what made us so great as a species.
Sorry for the overly long answer, but this was a fun thought experiment and I wanted to see what I could do with it. I hope this gives you some ideas for your world.
[Answer]
# We already did it
The world is already mostly flooded by the ocean, and people have reclaimed land from the ocean and built cities here. (For instance, look at The Netherlands).
Sure, the initial step will be very hard, but as all answers assume resources and machines to be available, here is what you could do:
1. Find a place where the ocean is not that deep
2. Build a wall around it
3. Pump out the water
This is how the dutch got about half their country, so unless the ocean is prohibitively deep everywhere, it is definitely possible to do this on a scale that supports massive cities.
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[Question]
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***RIDGEFIELD PARK, NJ** – April 2, 2019 – Samsung Electronics America, Inc. announced that the new, award-winning Galaxy S11 and Galaxy S11+, which have been recognized by smartphone reviewers worldwide for their best-in-class display, design and camera, are now available for purchase at U.S. wireless network providers and retail stores....*
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> The only problem is, they released a camera with combined visible light and thermal imaging capable of taking an accurate picture of a person's retina. You see, I convinced my company to let me buy one for App testing, just to see what it could do. I stopped Dr. Hayworth in the hall and asked if I could take her picture for an upcoming online marketing campaign, and she happily complied.
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> Then I told her there wasn't a campaign and that I really wanted to test the company's security. She was angry, but not as angry as when we walked to her secure lab and I showed the biometric scanner the image I took of her eyes. Heaven forgive me, but the shade of angry red she turned when the door unlocked was actually really pretty....
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> At least she backed me up when we went to the executive staff and told them any idiot with one of these phones could walk into every secured part of the building. They were pretty straight-faced when they applauded my initiative — and then they ordered me to contact BioSmart and ask them what we should do about the millions of dollars we spent buying and installing their retina scanners last month.
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Ladies and gentlemen, you're the lead engineer at BioSmart Retina Scanners, Inc. The company has scanners installed world-wide, but the world doesn't know (yet) that they can now be beaten by a mischievous 9-year-old.
After getting off the phone with the client and quickly changing his underwear, your CEO invited you to think *very quickly* about how to deal with a smartphone that can outsmart your 2018 retina scanner. You have 24 hours to come up with a viable idea for salvaging the scanners before he shares his bathroom plumbing frustrations with the whole company.
**Question:** What ideas do you have to modify 2018 retina scanners to compensate for smartphones that can take pictures of people's retinas and display them with enough precision to fool the scanners?
**Non-Narrative Background**
* We're on a near-future Earth.
* BioSmart's scanning technology exists or is licensed around the world. A failure to find a fix will not only destroy BioSmart Inc., but will have global security ramifications.
* Existing and near-future technology is allowed. No Clarkean Magic, though. If you can't credibly convince me/us that your solution is viable in, say, less than 10 years, then it's not an answer. *(Yes, my storyline says 2019, but that's likely too limiting for useful answers.)*
* We'll skip the economics of fixing the problem, so replacing the old units with new units that solve the problem is OK (even assumed). Yes, this is a bit of fanciful magic, but I'm only interested in the nature of the fix, not how to roll it out.
[Answer]
First of all, let's clear up a myth.
Retina scanning is NOT the most useful form of biometric comparison technique out there; iris scanning is. It's a small point, but from the literature I've read on the subject (primarily while studying biometrics as part of my Masters (I'll admit that's a while back now) iris scanning has two primary advantages over other forms of scanning.
1) The data signature is very small (around 2k of data) - so small it can be almost encoded into one of those smartphone 2D barcode grids
2) VERY tight DET (Detection Error Tradeoff) curve which just means it's highly accurate.
Because irises are effectively muscles that tear as the eye grows through life, you even solve the 'identical twin' problem with DNA scanning. The tears are random. Also, the Iris is sensitve to NIR (Near Infrared) light, meaning that you add a NIR pulse to your flash and it not only contracts the pupil (dilates the iris to make it bigger for the scan) but it doubles as a liveness test. You can't just pluck out someone's eye and put it to a scanner; the NIR pulse wouldn't make the eye react so it would fail the test.
THIS is essentially your answer; take your retinal scanners and convert them with a similar NIR pulse that tests for liveness. This is not done on retinal scanners today because you don't actually want to contract the pupil; you really want it as dilated as possible so you can see through it to the retina. So, take your picture of the retina, and then trigger the flash and test for the iris dilation. Personally, I think you're better off not having bought them in the first place and going with iris scanners instead but admittedly this is a personal preference.
Of course, the next thing that will happen is that smartphones will now come with daylight strength screens. They'll have a lux meter on the front which will test for ambient light levels, and they'll increase screen contrast somehow when you're trying to look at it in broad daylight. When THAT happens, someone will write a little program that will automatically morph your image of an iris into a dilated pupil configuration when the lux meter detects an NIR pulse.
But that, Sir, is a problem for the next generation.
[Answer]
Use two cameras on the retina scanners. Phone screens are flat and retinas are not.
Aside from that, phone screens don't display the infrared data in the infrared spectrum, else humans couldn't see it. So, by using infrared cameras in the scanners, the phone screen will appear a uniform temperature, with none of the thermal detail of a retina.
[Answer]
Biometry such as the one you propose is based on [pattern recognition](https://en.m.wikipedia.org/wiki/Pattern_recognition). It doesn't take a genius developer to make the machine recognize what is around an iris is a handheld device, not a human head. The system may just as easily be programmed by the manager's nephew to sound an alarm and call security if you try to be a smartass.
If someone tried to pull that move, they would just be showcasing how foolish they are. If however they try it and succeed, all it does is revealling that some coder who has just learned about biometrics was being paid by line of code written, not by productivity. Next patch will certainly fix this asinine bug, and the company who did this will receive a homage at TheDailyWTF.com, an older creation from the same minds behind this very site here, whose only purpose is to record and mock the work of incompetent coders.
You would have an easier time trying to trick fingerprint scanners, which usually cannot look around the mark they have to scan. But I doubt you would find one that you could fool with a cell phone.
[Answer]
Today's images [as ones being publicized in a press release](http://www.planetbiometrics.com/article-details/i/3644/) (which means: publicly available!) already have a resolution high enough to fool iris scans. Retina scans might be a bit more difficult since it actually requires to shine some (infrared) light into the eye to get a clear picture, but a "nightshot" mode on tomorrow's smartphones may actually provide it.
So we're not just talking about a "what if", but a distinct possibility for near future hardware.
Thing is, the problem is quite the same as it had been with touchless fingerprint detection. These devices use high-resolution cameras to get an image of the ridges and valleys of the fingertip, but first-generation devices were easily fooled with photos or fingers being cut off for a more grisly choice.
To counter that, device makers introduced a "life finger detection" where temperature and even pulse in the capillaries are checked to see if it's an actual live finger rather than a dead one, possibly even warmed back up to body temperature.
Same would go with retina scanning. A second camera could try to take in the whole face to see if it belongs to a living person, or a series of images of the retina is taken to decide whether the device is looking at a still image or the capillaries of a living eye.
While these methods may not be foolproof themselves, they do actually raise the bar from 'just the casual intruder showing a snapshot to the sensor' to 'a determined attempt at bypassing security'.
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[Question]
[
I've read several of the questions about language shifting and diffusion here, and it has unfortunately left me more unsure of things than I was before.
Situation:
Colonists on an arid planet speak two major languages, Hindi and American English, there are also spacers who speak English as well.
There is a disaster and around thirty thousand people survive split up into groups all over the planet in groups ranging from a few dozen to about a thousand, with the low hundreds being the average. They are based around oases, springs, and along the coastline of a polar sea.
Due to being cut off by arid and hostile land, most of these groups are fairly isolated from each other for the first five hundred or so years. Only the people on the sea which has the largest population interact and trade in large numbers. After that point trade caravans would spend the next five to six centuries reconnecting the towns and cities together, until even the smallest settlement sees a caravan once a year and major cities have a steady flow of travelers.
The only written documents saved from before the fall are technical manuals, a few scrapes of books, and what the survivors write down.
Realistically, after 1500 years how much would the language have diverged among the settlements.
**Edit**
Would the various towns and cities be able to talk to each other easily, would they speak a creole that everyone can pick up in a few hours, or would they have totally different languages?
**Edit 2:**
English was the language for administration purposes. Hindi was more for cultural purposes amongst half the colonists.
**Edit 3**
The initial tech level after the fall is limited. Due to loss of satellites, and most infrastructure, almost all radios are handheld and only really of use within short distances of the camps. If conditions are just right some radio communication can occur several hundred kilometers away, but this is beyond the ability of most survivors.
Communication is largely by foot or short range planes and ground cars, with no way to maintain them, these fail within a decade.
After this point people stay in touch via camel, horse or wagons pulled by animals. They know how to do everything they need, but don't have the capabilities, by the time they start getting the capability most of the knowledge is gone.
[Answer]
Something to keep in mind is dialect shift. If the dialect shifts enough, it can become another language. One of the most amusing things that ever happened to me was watching a movie in Portuguese, not realizing it was Portuguese, and thinking it was the lousiest Spanish dialect I'd ever heard. I understood 85% of it, and assumed any words I didn't get were those that had just been slurred by the "crap" accent, and then I turned the subtitles on and realized it was Portuguese.
If you know a second language, say, in the Romance family (Latin, French, Spanish, Italian, Portuguese) listen to one of the near relatives and you can pick out what sounds/words remain consistent across languages so you can get an idea of what vowel shift sounds like.
If you don't know a second language the website here can help: [Romance Language Comparisons](http://ielanguages.com/romance_phrases.html) by showing you the similarities between Romance languages for given vocabulary and phrases
So, for example "Good Morning/Good day" in English is:
*Bonjour* in French, *Buongiorno* in Italian, *Buenos dias* in Spanish, *Bom dia* in Portuguese. Note the way "Bom"/"buom"/"buen"/"Bon" hangs on as part of the greeting. That can give you an idea of what sorts of sounds will remain and become part of a new language.
It is also worth considering what might get lopped off, or changed as linguistics shift. Disclosure: I have a contract job evaluating standardized test response for an educational company. Lately the tests have expanded to include short essays. But these are essays written as English as a Second Language from native Spanish speakers. So, Spanish rules about spelling and word order are applied to English vocabulary, due to.... well, shit teaching methods focused too much on getting the right accent than syntax rules. The resulting essays.... are weird.
We see words words like "yogurt" getting written like "llogul" (ll in Spanish has a sound like an English g or j or in this sense y), "horse" appears like "jors" (the starting h in a Spanish word is silent, 'habichuelas'[beans] is pronounced like "abichuelas" with the ch -depending on the speaker- sounding like ch from "choo-choo" or "sh" like 'shush'; "daughter" comes out as "dotar'. We have an informal competition about who gets the 'zinger', the one word/phrase that just makes the reader ready to tear their eyes out at the fail. (Last year's "winner" was "*nospiki/Ynospiqui*" which took steps to break down as: "Y No spiqui" > "I No speak" to mean "I don't speak" as in, the non-answer, "I don't speak [English]." ('Y' being used in a really weirdly pronounced way as a way to transliterate 'I', because sometimes here I gets pronounced as eI, which sounds similar to y (not like "why" but as "ee" as in "Eek, a mouse!" in Spanish)
So, once these people of yours are isolated from each other,you're going to get linguistic shifts just due to bottlenecking factors. If you have a group where everyone pronounces'horse' like 'jors', then that's probably going to be how they write it too. This is sort of found in the difference whether the Pepsi soft drink is called ["pop", "soda" or "coke"](http://popvssoda.com/) depending on where you are in the United States. All in all, lingual shifts are fascinating to watch happen. In short, start listening to where native Hindi speakers start to butcher English and use that as seeds for dialect/creole shifts, from there, follow the shifts to a logical and stable conclusion. "Nospiqui" ended up being an extremely consistent and common non-answer across school locations, down to the spelling.
If you'd like to read up on linguistic shifts, the book *The Story of English* by Robert McCrum et.al, starts at where English began as a Germanic dialect to today. The BBC did a nine-episode hour long series on the book as well, so that could be a way to fast-track learn about it.
English itself developed in that fashion from it's ur-germanic predecessor. This [link](https://web.cn.edu/kwheeler/diagram_4English.html) is to the page hosting this chart, but it's a whole website
[](https://i.stack.imgur.com/PCABE.gif)
Edit: In the "nospiqui" example, I forgot to mention that another learner problem was not being able to tell where one word ended and another began when they were listening to English. That's how 'I don't speak' merged into 1 word.
Edit2: In the horse to jors example. Consider how the language would further evolve from that base as it moves away from it's source material. H and J are given here to have the same H sound, following the Spanish pronunciation rules. However, an English group then pronounces J like "jar" so in reading the new writing for 'horse' call it a 'jors' (djorse or djyour with a silent final s, while another group reads j like a d and calls it a 'dor'). So, in three iterations 'horse' has become 'dor': horse > jors > dor(s).
Edit3: I really can't believe I forgot this paper. So, in addition to above mentioned pure dialect shifts, seems there is a correlation between climate and tonal languages. A 2015 paper found that climate factors such as aridity have effects on vocal cord movement. So complex musical vocal tones are unlikely to develop in arid climates, due to drying effects of having to lose so much moisture by breathing outwards (if you've ever given a lecture or speech, a dry throat is painful). The paper is: *Climate, vocal folds, and tonal languages: Connecting the physiological and geograpic dots* by Everett, Blasi and Roberts. Published in PNAS, it's available for reading here: <http://www.pnas.org/content/112/5/1322>
[Answer]
1500 years ago old english was just starting to be a distinct. Now it's mutually unintelligible with the its modern form and the languages it's closest related to. That's with 1500 years of close contact, trade, and diplomacy between each language.
It stands to reason that if you want your much more isolated settlements to be unable to speak to each other that's an entirely plausible assumption. It could also be possible that much less linguistic drift happened, medieval Icelandic manuscripts can still be read today by modern speakers of the language.
Pick what makes sense for your story between these two extremes.
[Answer]
1) A starting point speaking two different languages doesn't make sense. Space travel/colonization requires close collaboration. There would be one common language. The other, at best, would be culturally spoken in the home.
2) The culturally spoken language has the greater chance of being preserved with the fewest modifications due to the natural desire to preserve heritage. However, without books and over the very long timespan you're proposing, this might be an irrelevant fact.
3) Let's consider the [Saami languages](https://en.wikipedia.org/wiki/Sami_languages). "Saami" (made up at one time of at least a dozen dialects) was not a written language. Add to this that the rugged northern landscape kept groups of Saami-speaking people very isolated for very long periods of time. What resulted is that many of the dialects were appreciably unintelligible to others. And this only over the course of hundreds of years. Since the late 70s linguists have been phonetically mapping the languages.
So...
A) People in high isolation will alter their language faster and more thoroughly than anyone else.
B) If the area has a common element, the language will often build around that element. For example, the Saami people have a great many (a great many) words involving snow, ice, and reindeer. So many that an attempt to translate even into a similar language would be frustrating due to all the definitional subtleties. Similar language focus would occur with communities heavily focused on lumber, fish, military, trade, the sea, mountains, plains, etc., etc., etc. (I can easily believe dozens of words describing the gentle Susurrations of the wind across plains grass). In other words, your communities may develop *specialized vocabulary* due to the specific location, climate, or trade they enjoy.
C) People enjoying large amounts of trade will have the lowest rate of unintelligibility, but that might be deceptive. The tradesmen will enjoy it (or, more accurately, their ship/caravan captains or negotiating reps will), but not necessarily the general populace. The people will have a greater exposure to vocabulary ("Did you enjoy the *Rabins?* They just came on on the last caravan! Heck if I know if that's how you pronounce the word, it's what I thought the trade master called them.") But that's generally going to be nouns, not verbs, which means their actual ability to communicate is only moderately better.
D) What would change all this would be the development of schools and universities (and, of course, *books*) in the key trading towns and the ability for people to travel (more or less) freely along the trade routes. That would substantially increase the intelligibility between groups who enjoy trade as, over time, more and more people of each community return from their great educational adventure. It would also sharpen the distinction between trade-bound communities and isolated communities.
[Answer]
Several things may prompt changes in language:
## Region-specific features
Think the great plains (where I live). The vast majority of the world's tornadoes happen here. In the 1700s, Europeans had barely any documented tornadoes and most people thought they were a superstition. Fast forward to American colonization, and more and more tornadoes are spotted. Now, people generally accept tornadoes as a fact. This arid desert could also have new flora, fauna, weather, and environment. Each would have new words, possible idioms (?). However, you mean a divergence in grammar and other fundamental components.
## Dialects
On the [wikipedia page](https://en.wikipedia.org/wiki/Tree_model#Most_feasible_network_for_Indo-European) for the Indo-European language tree, Anatolian, Tocharian, and other proto-languages separated over a period of time comparable to your time period. We can set this as a reasonable upper limit for language divergence. Meanwhile, the separation of American English from British English should be a minimum, because the period of time is shorter and the degree of separation is smaller. So, you should expect the language to develop into dialects like Chinese, where everyone speaks Mandarin, but there are many other dialects. From [wikipedia](https://en.wikipedia.org/wiki/Varieties_of_Chinese#Dialect_groups):
>
> Mandarin (66.2%)
>
>
> Min (6.2%)
>
>
> Wu (6.1%)
>
>
> Jin (5.2%)
>
>
> Yue (4.9%)
>
>
> Gan (4.0%)
>
>
> Hakka (3.5%)
>
>
> Xiang (3.0%)
>
>
> Huizhou (0.3%)
>
>
> Pinghua, others (0.6%)
>
>
>
[Answer]
First, you have to take in consideration that English is not a "same" language everywhere, and has various language variations. Take in consideration just contemporary times - i know American folk who can barely understand Scottish or Aussie people with thick accent. Then where are "newer" local or demo-graphical variations of English like Jive talk and some localized variants in Caribbean.
Just to paint how different variations of one language can be - My mother language is Serbian, i live in the north, and sometimes can't fully understand people from the south if they speak too fast between eachother, because they don't use all 7 cases, some tenses and so on. And its a small territory, much less people using it, along with constant interactions between them.
So, imagine that only on way broader scale, for English and Hindi language (i dont know anything about Hindi so i won't talk about it).
So, you have to ask yourself one more question - the demo-graphical background of the colonists (at least that half that only uses English) - they might all speak English, but its less likely that English is indeed their culturally 1st language of choice, especially in the age of colonization of new planets. And people with similar cultural background tend to stick together in "new" environments, as proven.
So, yea, in isolation, depending of the people in the settlements, they would create a localized variants, but i would never call it a completely different language.
The base of each of those language is the same, so they would be able to understand eachother, with difficulties perhaps, but i wouldn't call it a completely different language, and that language will be influenced a lot by the ethnos of people living there.
Only case when they wouldn't be able to understand eachother at all is that if one group of people switches completely on English or Hindu (or some variations of it), and totally neglect the other one, which, in those 1500 years period (or even less) is enough to completely disappear. So a trader comes from English based settlement, and tries to interact with Hindi based settlement - well, you go into northern India now with no knowledge of language there and try to negotiate and trade.
And claim that i read in other answers that people in isolation will alter their language faster and more thoroughly is not true. It is COMPLETELY THE OPPOSITE. People in isolation will preserve as much as possible of the original language, unlike people who have contact with other sources.
Example - Scandinavian languages - all derive from the same base - Proto Norse. To not go overly into details - Icelandic and Faroese people have been the most isolated - and their language is the most similar to the base language all came from. Old-Icelandic and Modern Icelandic are, grammatically, very very similar. I've been using Old Icelandic on work before i learned normal one, and everyone understood me. But on the other hand, Swedish, Norwegian, Danish, they changed a lot because of influences from abroad, due to trade, wars, conquests and so on, so in those languages today you have words that are not Germanic or Scandinavian in origin.
Hope this helps. Cheers.
] |
[Question]
[
On saturn's north pole there is a hexagonal cloud which does not move.
My question is: is it possible to theoretically make a hexagonal cloud on an earth-like planet? And furthermore, is it possible to "freeze" clouds in mid-air so that light doesn't pass through in certain places?
[Answer]
**Yes.** Vortices on earth or anywhere, large or small can form polygons with up to 6 sides.
from <http://physicsworld.com/cws/article/news/2008/may/08/polar-vortex-replicated-in-a-bucket>
[](https://i.stack.imgur.com/cTAKP.jpg)
The linked video shows a spinning vortex in a bucket taking on polygonal shapes with up to 6 sides.
<https://vimeo.com/38921493>
I must admit that although they demonstrate these polygonal vortices in their bucket with a rotating bottom, it remains unclear to me why the shapes form. Definitely each shape is associated with a given rotational speed. Perhaps the shapes have to do with rebounding of certain wave frequencies back into the ring to form [standing waves](http://www.physicsclassroom.com/class/sound/Lesson-4/Standing-Wave-Patterns) - as seen in this excellent youtube video of a dish of water excited by sound waves.
<https://www.youtube.com/watch?v=hYmx2ltHbug>
[](https://i.stack.imgur.com/HhbRo.jpg)
Following this reasoning, one would predict polygonal vortices would sometimes be observed on earth. And they are.
from <https://www.wunderground.com/blog/24hourprof/mesovortices-in-the-eye-of-super-typhoon-haiyan.html>
>
> Curiously, these mesovortices in the eyes of very strong hurricanes
> sometimes take on polygonal shapes... Indeed,
> eyes with polygonal shapes ranging from triangular to hexagonal have
> been observed on high-resolution satellite imagery. Granted, the sides
> of the polygons sometimes don't exactly connect, but this imperfection
> should not dilute my message here.
>
>
>
[](https://i.stack.imgur.com/44hOP.jpg)
---
Re: freezing a cloud in the sky.
If the circumstances that give rise to the cloud are related to an immobile topographical feature on the ground, the cloud will also be stationary or "frozen". An example of this are [lenticular clouds](https://www.accuweather.com/en/weather-news/photos-lenticular-clouds-texas/47884790).
[](https://i.stack.imgur.com/5e1Jx.jpg)
<https://www.cntraveler.com/stories/2015-11-10/ufo-clouds-spotted-over-cape-town-south-africa>
Depicted: Table Mountain in Capetown which is apparently known for frequently hosting such clouds. You can find lots of images.
The lenticular cloud is formed by moisture-laden air hitting the mountain, being forced up, and then reaching a point where the temperature causes the moisture to condense into a cloud which sits there on or just over the mountain. I found a quote which notes such clouds are permanent in the same way a waterfall is permanent - individuals drops of moisture condense and move away but the formation appears static because it is continually replenished from new moisture.
[Answer]
We don't understand why Saturn has a hexagonal cloud but it is unlikely that the same mechanisms would form a cloud on an earth like planet.
However, mountains and the presence of water and other terrain features can shape cloud formation so I think it is likely that you could get Hexagonal cloud cover if you had the exact perfect terrain.
Secondly, while you cannot technically freeze a cloud (The cloud will move with the wind or tend to disperse. There are places on the earth that have cloud cover 97% of days. So if your terrain generates cloud cover as fast as it is dispersed you might get cloud cover very close to 100% of the time.
Reference: <https://www.currentresults.com/Weather-Extremes/US/cloudiest.php>
[Answer]
-We dont fully understand the process of how Saturn has a hexagonal cloud.
-On Earth there is a phenomena that results in a aerial hexagonal structure called an [Air Bomb](https://en.wikipedia.org/wiki/Air_bomb). This isn't a cloud more the absence of resulting in that geometry. This does show one way a natural process can result in that shape. So theoretically it is plausible you could create such a cloud by trapping a cloud in a honeycomb of air bombs.
-Can you freeze a cloud? No, what is it called when a cloud gets frozen? **SNOW**
-You dont need to freeze a cloud to block out light, just make it thicker/denser.
[](https://i.stack.imgur.com/STSIT.jpg)
[Answer]
Typical Earth-like clouds are formed from the mixture of warm moist air with cooler air, and their movement across the globe is caused by wind forces. You could create a terrain that feeds the warm wet air from below and funnels the surrounding winds into a vortex to keep the clouds in place.
There are also clouds of smoke and dust. Once you create the dust cloud it could be corralled using winds as well, or perhaps some kind of electostatic or gravitational field local to that area of the globe.
] |
[Question]
[
I'm in the early stages of designing a city, and would like some advice about to structure its roads realistically for transport.
The city is circular, *with large roads entering the city at north/south/east/west*. It should also be *on higher ground* - doesn't have to crown a mountain, but should be higher than the rest of the immediate countryside.
Given that:
(a) the world uses medieval technology;
(b) horses/horse-and-cart are the most sensible long distance transport;
(c) the roads are straight;
and (d) there is no magic,
**HOW STEEP CAN THESE MAIN ROADS BE?**
If I can't sensibly have straight roads and an impressive-enough gradient, then I'll redesign the city with a different design. Still, it'd be nice to go along with my current mental image!
**Further contextual information:**
The city is divided into concentric rings, with the palace at the centre and the poorest at the outskirts. A significant slope would therefore make the palace even more impressive to viewers.
The city evolved from a simple trading town at a set of crossroads, but developed in importance and resources. The straight roads are a remnant of that past - while they're not the best defensively, internal walls divide class districts, and are each equipped with defences. (Being on higher ground also helps for defence).
The area may have once been volcanic - the city is fed by natural springs, and may explain a hilly/mountainous terrain.
I've also had a look [here](https://worldbuilding.stackexchange.com/questions/3135/a-realistic-road-network) for info about road-building, but it didn't seem to cover this.
[Answer]
The story about the development of cable cars in San Francisco involved an accident with a horse drawn car on an 8.3% grade.
from <http://www.sfchronicle.com/bayarea/article/Steep-S-F-hills-overcome-with-Hallidie-s-cable-6295164.php>
>
> As a team of horses pulling a streetcar up the 8.3 percent grade
> approached the intersection, one of the horses slipped on the wet
> cobblestones. The driver applied the brake so hard the chain was
> ripped out and the car slid downhill, dragging the horses over the
> pavement. The car came to a rest at the bottom of the grade, and the
> horses were mutilated and killed.
>
>
>
The fact that the driver was trying it meant that it was part of the normal route. I could not find how much the car weighed but I did find that passengers would routinely disembark and walk along side the car on the steep parts of the line, which were barely within the capability of the horses.
I found this fine math on
<https://www.reddit.com/r/rpg/comments/12xtqs/what_is_the_gradeability_of_a_horsedrawn_wagon/>
>
> [–]Azza\_bamboo 1 point 4 years ago\* I might be wrong on the
> following, so I'd urge any physicists to look at what I'm saying and
> see if there's any mistakes. A horse has a mass of about 400kg and
> pulls about 801N. Let's say a laden carriage has a mass of about
> 1000kg. So a carriage pulled by four horses has 3200N pulling it, and
> has a mass of 2600kg. The force of this vehicle under gravity (which
> is the technical meaning of weight) would be 25506N. Put simply, the
> horses could not pull their own weight, plus that of the carriage,
> straight upwards (ignoring that it'd be impossible for their hooves to
> gain traction on a vertical face). An incline allows them to pull only
> a fraction of the total weight rather than the whole lot. 25506
> multiplied by the sine of the maximum theoretical incline = 3200. This
> is because 3200 is the force the horses can give, and 25506 is the
> weight of the whole vehicle. The angle that would make the force that
> the horses have to pull be equal to 3200 is the variable we're trying
> to work out. The arcsine of (3204 divided by 25506) is roughly seven
> degrees. In other words, the incline had better be less than 7 degrees
> else these horses won't be able to pull this wagon. Sources The mass
> of a horse: <http://en.wikipedia.org/wiki/Horse#Size_and_measurement>
> The force a horse exerts:
> <http://en.wikipedia.org/wiki/Horsepower#History_of_the_unit> (Google
> calculated that 180lbs of force translates to roughly 800N) I will
> admit that I simply made a judgement on the mass of a loaded carriage,
> putting it at a metric ton. I have calculated that the incline needed
> for the same horses pulling a 500kg carriage is roughly 9 degrees. Of
> course, you're trying to maximise the proportion of force to mass.
> That is, you want more force and less mass to be able to make greater
> inclines. Also, humans don't really get to dictate the landscape. So
> if you're trying to get big loads up a steep hill, you might use lots
> of horses to carry less mass. In reality, rather than asking what
> incline is reasonable for this carriage, you ask what setup is
> reasonable for this incline.
>
>
>
So maximum grade for a horse with a wagon would be between 7 and 9%, which jibes with the story about the accident on the 8.3% grade. Like your city, San Francisco was laid out without any concern about grade and there are many streets which were (and are) [much steeper](https://priceonomics.com/the-steepest-streets-in-/). You would just not be able to take a cart on those streets - you would have to walk or ride horseback.
[Answer]
Most of these questions are the wrong questions. If you were to ask 'when should I use a 10% grade' the answer would be never unless you could absolutly not avoid it. Roads are a means of commerce in the real world. Roman roads are a poor example of roads because they were not built to move goods or services but to move armies. A marching soldier has zero rolling resistance. Traversing inclines on foot is rather easy. A man might even traverse a grade of 100% using a ladder.
All of this changes dramaticly when a wagon becomes involved. A draft horse can reasonably pull a wagonload of aproximatly 1 ton over a level good road for a day at around 2.5 miles an hour. This is basicly one calculated horsepower. Now lets say you increase the grade to 2%. Now you have added 40lbs of energy pulling in opposite direction. This essentialy doubles the energy requirements in terms of horsepower. At a 6% grade you have doubled the requirment again and at under 15% you have doubled it a third time.
Could you have a horse pull a one ton load up a 15% grade? Yes, maybe. A horse can generate up to 15Hp in pulling force for a short time. But after an hour you would have to change horses. This means that a 2% grade road 10 miles long and level road 20 miles long are about equivelant in roads you could travel in a single day.
This why roads tend to wind. The economic return on a level road that winds is far greater than a straigt road with a steep grade.
[](https://i.stack.imgur.com/JOMDE.jpg)
[Answer]
I've ridden a horse up a 20%-25% gradient many times. Horse riding is not going to be your limiting factor.
[Answer]
There is a long distance pack horse trail through our region. Short sections are between 20 and 30%. The climbs and descents are quite manageable for the horses. But at those gradients drainage and erosion become big factors and both horses and people will only be able to move slowly up and down.
[Answer]
From wikipedia on Roman Roads
>
> Roman construction took a directional straightness. Many long sections are ruler-straight, but it should not be thought that all of them were. Some links in the network were as long as 55 miles (89 km). **Gradients of 10%–12% are known in ordinary terrain, 15%–20% in mountainous country**. The Roman emphasis on constructing straight roads often resulted in steep slopes relatively impractical for most commercial traffic; over the years the Romans themselves realized this and built longer, but more manageable, alternatives to existing roads. Roman roads generally went straight up and down hills, rather than in a serpentine pattern.
>
>
>
<https://en.wikipedia.org/wiki/Roman_roads#Construction_and_engineering>
So, if the road builders are stubborn the roads could be 15%–20%, but more sensibly they would be 10%–12% with some switchbacks.
[Answer]
This may seem obvious but it depends on whether you're going up or down and how heavy the loads are, you could have much steeper exit roads for empty wagons going down away from the city than you can entry roads bringing heavy loads up into the city.
[Answer]
Where I live, horses are used to pull timber in areas where machinery can't reach. They seldom pull the logs up the slope, but they do work with considerable loads in quite treacherous terrain.
These horses are bred and trained for this purpose, and they use special horseshoes designed to grip the dirt.
Since your question specifically pertains to a city environment, I presume you want paved roads. However, this can be very dangerous for horses pulling anything uphill or downhill, as such roads offer very little traction for hooves. The use of horseshoes actually makes it even more perilous. (Yet many traders coming to your city would have their horses shoed specifically for better off-road performance.)
The best way to make the slope accessible for horses is to rebuild parts of the roads into an [Equestrian staircase](https://en.wikipedia.org/wiki/Equestrian_staircase) (combined with ramps for the wagon's wheels). This way, horses can pull their cargo without the danger of slipping and can "force-pull" heavy loads step by step, taking pauses between pulls. Ridging in steps will help to get traction for shoed horses.
If you wanted to maximize the slope, you can use counterweighted pulleys at strategic points to assist the horses up the hill. These could also serve as convenient tolling points. (Perhaps the toll amount could be calculated based on the amount of ballast used for counterweight.)
The grade wouldn't necessarily need to be uniform, but you could aim for a bit steeper than the 9% suggested in the accepted answer on average.
As for getting the loaded wagons down from the city, [this video shows how logs are pushed down the hill](https://www.youtube.com/watch?v=EEYe4Wh0YiE).
>
> First, a horse is used to position the log with the "thin" side downhill. Then, the log is hooked to the harness, and the horse, going diagonally down and across the slope (rather than directly down), gives it a push downhill.
>
>
>
If the roads are wide enough, a similar technique can be used to safely get cargo down from your city. The wagon would be placed on a sledge, which would be pushed down the slope. When traction inevitably stops it, the horse would give it an additional push until the sledge is safely down.
] |
[Question]
[
I was told to post this question separately, so here it is. I need help with the geography and climate of my map.
[](https://i.stack.imgur.com/NlAXK.jpg)
* Blue circles are ports
* Gray circles are cities
* That one brown circle is a town
* The continent is located in the southern hemisphere
* The world has roughly medieval technology
* Magic exists, but isn't powerful enough to move mountains or anything
So, with the above things considered, I ask the following questions:
* How realistic is this map's geography and climate?
* How can I make the map look less empty, geography-wise?
[Answer]
First off the bat, I see three obvious problems.
You've got a desert, or at least a very arid zone, which occupies the entire width, from shore to shore, of a long continent with ocean on either side. What are the coastlines like?
Why is it so arid? We'd usually have lack of water for a combination of two reasons: no rain or no soil. Mountains or altitude can prevent rain from reaching an arid zone, but we have no mountains here. Let's look at the rivers.
You have one that seems to come from an upwelling and flow west for a short distance. It apparently doesn't irrigate much of the surrounding land, so I'd suppose that it sits in the middle of a basin. You have another river that flows east for a longer distance. Rivers can often be quite limited in the fertile area that they feed — e.g. the Nile in Egypt, — so that works well enough in that regard. This one seems to have a subterranean source, too, since it is in the middle of a land that sees no precipitation to feed it.
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What you have there is a large arid region apparently sitting at a high altitude on a plateau of land which can't hold water above the bedrock, and which is sitting atop a large aquifer (i.e. lots of water between the granules of rocks underground). But, it doesn't really look like that when you examine the coasts. Besides, what would keep the aquifer held together so far above sea level?
You have a isolated range of mountains, the “Desmonles” or something like, which does not seem to follow the contours of the surrounding landmass. Is there a reason for it to be so straight?
Your two big marshes look a little ill-situated. Like they don't actually come from the rivers, but were simply stamped down at their mouths.
Maybe the rivers meet huge basins that get flooded — but 120 miles away from the river seems rather far.
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Those were the things which I noticed first. Other answers have mentioned some of the other problems, especially with the rivers — like that one apparently inland sea or something in the northeast, — so I will not rehash them here.
I will say that you need to give some indication of both latitude and compass directions. Never mind the terrain itself, but if you expect people to see this map as a small part of a larger globe much like the Earth, they need some points of reference. Otherwise, you'll end up with people either presuming that it is equatorial, at their own native latitude, or in some flat fantasy world with a single, and probably temperate, climate over the entire thing.
Okay, enough about that. All in all, don't take my comments too harshly or too seriously. I was going for frankness in my assessments.
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As for the large bland patches, remember that there are probably lots of hills, forests, springs, farms, and waterways in those places — they simply weren't large or dense enough to register on your map.
The large land of Morizar and Alsakubraa, for example, is comparable in size to places like the Arab peninsula or Ontario. The entire map would fit nicely inside Australia, and the habitable land surface area could almost snuggle together in the Outback.
The sparseness, the mountain contours, and the incompatible climates.
How would one address those concerns with their world?
I begin by drawing lines of longitude across my map. That will give you some idea of the seasonal climates in the areas. Then I can draw tectonic plates. Continental shelves go atop those. Coastlines and shallow seas and mountains come next.
Mountains usually go on the edges between the plates. In the middle of a plate, they are often caused by volcanism.
Drawing isoclinic contour lines, beginning at the coastlines and working inland, is the next step. Indeed, you already began at coastlines and mountains. Now, you need to fill in the lands between.
Another thing that helps is to work with smaller strokes. You have two large marshes, one giant aridland, and a one large jungle or something. Try to have a few smaller areas rather than those big clumps.
On the whole, a lot of fantasy maps are really just straight–up garbage — even published and selling, — so you are doing well enough. Why are some maps so bad? Because their designers didn't take them seriously. The problem is never one of how realistic your maps are, but how much you are willing to make them real.
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Well first you have a large desert with no mountainous border at the same latitude as several gigantic marshlands, that makes no sense. Deserts are generated by latitude(what portion of the hadley, ferrel, polar cell you are in) or terrain, this one appears to be made by neither. It also seems to have a lake in the center of it with no source for the lake.
on the right you have a mountain range running from coast to coast with marshes on both sides, which is basically impossible at the same latitude as a desert.
The only way to get both a marsh and a desert at the same latitude would be the rain shadow effect which you don't have. Look at South America for inspiration gigantic jungle on one side of the mountains, on the side of the prevailing wind (east to west) and on the other side of the mountains one of the driest deserts in existence because all the moisture was dumped going over the mountains. You really should think about what your prevailing wind direction is, your continent is not large enough to have more than two. They occur in pretty straightforward [bands](https://upload.wikimedia.org/wikipedia/commons/thumb/9/9c/Earth_Global_Circulation_-_en.svg/1200px-Earth_Global_Circulation_-_en.svg.png) ue to the planets rotation, them plus your latitude will control your climate. Also consider smoothing a few random parts of your coastline an entirely jagged coastline says post-glacial or extreme tectonics, so either you are close to the antarctic circle and thus should have no deserts without rain-shadow effect(see end) or you should have a lot of volcanics.
Second you need more forest, early civilizations and cities that do not have a steady source of timber don't survive for long. Deforestation is probably the second leading cause of city collapse after warfare. It is needed for building and for fuel, and cities need a lot of both.
third many of your rivers appear to start near the coast and flow inland, without the coast being mountainous this makes no sense. The Jiazhi area appear a particular offender.River maps are one of the harder thing to get right, I suggest looking at real drainage maps for inspiration. But generally if the river does not start in the mountains you have made it too long so it's end origin looks unrealistic. Rivers rarely cross so much of a land mass, especially small landmasses unless starting from mountainous terrain and simply can't flow towards the closer coast. One or two is fine but your map has a lot of them.
Extension of
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The only way you get that shape is if you had a massive volcano that blew and then sunk the continent in the past.
Horizontal Mountains generally don't happen, at least on Earth, because most of the movement of our plats horizontal and that generally would be the case for most planets. You do get a few horizontal mountains (such as the himilayas) but there aren't that many really. But beyond that the mountains seem random and like you have a island in the center that a bunch lands masses collided into from every angle rather than the result on natural formation.
You don't seem to quite have a grasp of river either. They starts from the high points (mountains) and flow down to the low point. This creates a lake or ends in the ocean or sea. Rivers don't split nor do they go to two different river mouths. Riers tell you the shape of the area around them, because each start of a river is the highest point and the joining spots are the basin/sub-basins low spot, meaning you can do a topological map just from looking at them and get fairly accurate. Right now you have 8 basins, which most continents do not have. The have like 2 or 3 usually.
Your marshs, forests, and deserts are probably messed up, but I can't say for certain because that takes working out wind and water patterns. I can tell you that you should probably have a lot more deserts, however small, due to all the mountains, and you should probably have a very lush forest covering most of one side of the continent due to the unlrealist volcano blown bowl shape you've made. The water from that area blow onto the mainland and case it to be wet...
That bowl shape is horrific btw if you're going to try to figure this our for real, because having water like that causes weather to go a bit wonky, because it creates a donut in air pressure which means you have lots of atmospheric and water current activity in that area, which causes the overall area to be a mess of incredibly stormy weather. I would not want to live there, just based off this. Though another guess as to what it might be like says it might not be that bad cuz it might have mediteranean weather modified to be hotter or colder as it goes further north or south.
But anyways, over all I'd give it a C, but most of the grade comes down due to the initial shape being so unrealistic. Ignore that, and it becomes a B, B+ largely due to the art quality being relatively good. But you get points taken off for mountaints being bad, ignoring that you'd get and A- to A. The art is good but not as good as I've seen and rivers themselfs, while there is problems with them, they are not that bad.
Considering each bit individually Continent Shape = F... Mountains = D ... Rivers = C... Climates = B-... Art = B+
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Another thing to consider, on top of everything everyone else is saying here, is your [symbology](http://wiki.gis.com/wiki/index.php/Symbology). The names of the mountain ranges are largely illegible, so they should have a more contrasting color, or be haloed with another color (white or black work well) to make them legible. Your difference between cities, ports, and towns would be a lot easier to see if you had different shapes for them. You could make cities squares and ports circles. Make the town a diamond. Whatever you do, for [your deity of choice]'s sake, include a **key**.
Alternatively, symbol wise, there are intuitive glyphs you can use to represent things. A üè† or ‚åÇ for a village, ‚öì for a port, üè∞ for a fortified city (and with medieval technology, what city doesn't have *some* sort of fortification?)
Combine all this with the other advice you're getting here regarding things like latitude/longitude lines, proper placement of mountains, etc. and you'll have a better—and much easier to understand—map.
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**This question already has answers here**:
[Are geographically typed planets realistic?](/questions/40/are-geographically-typed-planets-realistic)
(6 answers)
Closed 6 years ago.
Think of some famous outside-of-the-solar-system planets from say, Star Wars. Tatooine. Hoth.
They all have something in common: No matter where you land, the landscape is pretty much the same: on Tatooine it is a desert, possibly with some rocks; On Hoth it is all a frozen wasteland, with almost nightly blizards. It doesn't matter if you land on the pole or the equator, it is the same. However, on planet earth, we have locations where we can film all of thse planets, because of the diversity this planet.
Is it even possible to have such vast climatic zones, or is it just people being too lazy to create more ecosystems into their fictional worlds?
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**Yes, it is much harder to get Earth-like conditions than desert or ice**
Desert planets have [a much larger Goldilocks zone](http://www.astrobio.net/news-exclusive/alien-life-more-likely-on-dune-planets/) since, without so much water, they don't have the problem of icing up or a run away green house effect. This means desert planets could be much more likely homes for life. You would get some variation in temperature but there is no reason not to believe that it could be a desert all over the planet.
Similarly with an ice planet, once you've accepted ice on your planet there is a larger range of orbits your planet can have. Past a certain point the water will freeze up and lead to a positive feedback effect (more ice reflects more light back out and loses more heat, produces more ice..etc). The Earth has been through ice ages before but the surface area of the sea (where it is harder to form large ice sheets) was just too large for the ice age to last.
So both situations are possible, it would be **much harder to suppose you had a precisely balanced ecosystem, like the rain forest or jungle, covering a whole planet from pole to pole.** Ice and desert can, once they're in a certain temperature range, exist in a larger range of temperatures.
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According to some scientists, our planet has undergone a phase called "[snowball planet](https://en.wikipedia.org/wiki/Snowball_Earth)" in its past, when all the planet was completely covered, from the poles to the equator, by a huge layer of snow and ice.
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> The initiation of a snowball Earth event would involve some initial cooling mechanism, which would result in an increase in Earth's coverage of snow and ice. The increase in Earth's coverage of snow and ice would in turn increase Earth's albedo, which would result in positive feedback for cooling. If enough snow and ice accumulates, run-away cooling would result. This positive feedback is facilitated by an equatorial continental distribution, which would allow ice to accumulate in the regions closer to the equator, where solar radiation is most direct.
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So, in principle it can be possible.
Moreover, consider that movies like those you referred to are not focused on travelling the entire planet, therefore infering the planet climatology from them is like assuming all Earth is covered in skyscrapers just watching some Die Hard movies.
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I want to explain large Viking kingdom that keeps the worship of the Norse Gods (Odin, Thor, Loki) not the Christian nonsense of the Normans.
So I was thinking of bringing a Viking fleet to South Africa where they would be far away from disgusting missionaries and fight cool enemies such as Zulu or whatever tribes are there. The climate won't be so hot so they won't be at huge disadvantage against the locals.
I know that Vikings were excellent seaman, but I'm afraid if such trip isn't too far away for their [ships](http://www.danishnet.com/vikings/types-viking-ships/).
On the one hand technology is the most advanced in the later centuries, on the other hand Scandinavia becomes Christian at the 12th century which sucks.
How to bring enough Vikings in South Africa together with their women (or at least some of them)?
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Viking longships were not very suitable for long voyages. Their cargo ships, used for trading, called [Knarr](https://en.wikipedia.org/wiki/Knarr) could make long voyages, but they usually went along coasts rather than striking out into unknown oceans.
It's important to realise that raiding was a secondary activity: they'd raid somewhere if there was known to be good plunder that they could not get by trade. A raid involved collecting a lot of men, and convincing them the loot was worth the risk, and the loss of income from their normal work as traders, craftsmen or farmers.
So if they got to South Africa, they'd do it by coastal trading, possibly establishing bases along the way, if there was enough trade to make it worthwhile. And the problem with doing that down the coast of Africa is the tropical diseases you catch when you put into port. Scandinavians would have no resistance to them, and would die like flies. This will tend to put them off exploring further, because they're doing it as individual entrepreneurs, rather than because a king is saying "this must be done" and ignoring the casualties.
The only way to get them to do it is some wonderful land or treasure, there pretty much for the taking. This is difficult for you to achieve plausibly: they don't have a strong technological advantage over the inhabitants of South Africa.
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I was going to leave this as a comment but wanted explain a bit more.
The Zulu's and other 'bantu' speaking Africans spread from the Nigeria Basin area to the south of Africa a lot later than what you are wanting.
[](https://i.stack.imgur.com/geEU1.jpg) image from websearch on [bantu migration](http://www.keyword-suggestions.com/YmFudHUgIG1pZ3JhdGlvbg/) This migration pattern is based off linguistic studies of the South African Bantu Languages. yellow - before 3000BC to 500BC, orange - 500BC to 400AD and red - 400AD to 1100AD.
As you can see, the Bantu people only made it down to the southern reaches of Southern Africa after 1000AD, pushing other people and clans before them. The Zulu's would be found just above the 30degree South Line in circa 1709AD and the strong Zulu Kingdom of Shaka Zulu would only be formed in 1818AD.
There is the Kingdom of 'Mapungubwe' and Great Zimbabwe' at the Limpopo River, at about the 12th Century timeline. Their civilisation fell though, to drought and bad omens a few decades later.
If you are wanting Vikings to travel to South Africa before this 12 Century marker, they would actually encounter the hunter-gathers and other smaller tribes that were being pushed south by the Bantu expansion.
You could have the Vikings do this, create an established settlement and society and then have the Bantu Migration hit them from the North. Instead of melting away like the other tribes did in this timeline, you could have the Vikings halt the Bantu migration or at least hinder it. This would either prevent the rise of the Zulu Kingdom, or possibly allow it to rise earlier with different leaders. One thing is for sure, if there are Vikings in 1200AD...Shaka Zulu type leaders would be needed a lot earlier than 1818!
Also something else to note, The Chinese and other Indian and Asian traders made it to Mapungubwe (or at least the Maputo area, in Mozambique). There is evidence of glass beads and pottery etc. The Swahili language was created as a trade language (though I'm not sure if Chinese influenced it). You could have your Vikings have some interaction with the powerful Chinese Empire before they withdrew into isolation. Maybe even prevent them from withdrawing into isolation.
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Consider how the vikings got to [Constantinople](https://en.wikipedia.org/wiki/Varangian_Guard). Say that a similar mechanism took them a bit farther east, to Baghdad instead of Constantinople. Of course there may be problems if they are not "[people of the book](https://en.wikipedia.org/wiki/People_of_the_Book)" as Islam defines it, but some trade-focussed rulers might help to overcome that for a generation or two.
From there, they travel to [Zanzibar](https://en.wikipedia.org/wiki/Zanzibar#Before_1498) as bodyguards of some traders. Some headstrong young men resign that position and strike out farther south.
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If you would use some for of natural disaster like a storm you could make them reach further into new territory then they otherwise would do by themselfes and also unable to return. Having a storm push them all the way to South Afrika sounds unlikely, so maybe they somehow get to North Afrika and the storm pushes them south from there or they get pushed to north Afrika and sail down as they think its the way home/a more suitable settling space (colder).
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I have a series of weakly interconnected magical realms, in which there is limited movement between the realms. The technology in these realms varies from the medieval to the early 1800s. There is also magic very similar to that of the [Ars Magica RPG system](http://www.warehouse23.com/products/ars-magica-4th-edition-core-rulebook), however, I do not expect this to influence the answers to this question much, if at all.
In many, but not all, of these realms, slavery is legal. In some realms, despite its legality, it is not common, while in others it is very common, and slaves may make up over 50% of the population. Slavery may be for life, life until the slave can purchase their freedom, or for a certain duration (typically 20-25 years) after which the slave must be freed or the owner is enslaved as a penalty. There are variations as to the rights a slave has, from none (other than that a slave is a chattel of a certain value) to being guaranteed a certain minimum level of subsistence and the right to life.
In one particular small mountain-city realm of about 31 square kilometres, with early 1800s technology, slavery is legal, slaves have no rights, and slaves make up about 10% of the population, but slave-trading to nearby realms - quite a lot of them, given that the mountain moves about each day - is big business.
While the slaves that are sold *out* of the mountain realm fulfil all the roles that slaves can be expected to fulfil, in the mountain realm, since agriculture is almost non-existent due to its climate, most slaves are employed in domestic services, manufacturing and service industries, which is to say simplistically that they can be house, factory, labouring, shop or sex slaves. There are also some slaves with professional skills.
Slaves may be born slaves - the owner of a slave woman typically (this is the case in the mountain realm) has the power to decide whether her offspring will be slaves or free on an individual basis. Free people may sell themselves to clear family debts, or may be sold to clear otherwise unsecured personal debts that are sufficiently in default.
The realms the mountain realm visits includes some where slavery is legal but non-existent, and some where slavery is illegal, as well as many where slavery is legal and common.
However, the new goddess-queen of this realm is anti-slavery, having experienced life as a slave in some other realms on her way to the throne, and wants her kingdom to have nothing more to do with slavery. The Goddess-Queen is an absolute monarch. Her word is law, and she answers to no-one but recognises that she must at least consider public opinion if she wants her kingdom to flourish.
What would be the best way to abolish slavery in this kingdom? Over how short a time period might this be accomplished?
Please take into account what would happen to any freed slaves, how slaves, slave owners and slave traders might react, and how the society would have to adjust. In addition, since it is likely that the neighbouring realms would not be simultaneously changing their laws, how might relations with these realms change?
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# The Good News
The slaves in this world have a method by which they can be freed. Some people may even call this form of slavery an enhanced version of *[indentured servitude](https://en.wikipedia.org/wiki/Indentured_servant),* especially when some slaves have some rights in places. Due to the fact that some slaves can alter their station in life, like what the new queen-goddess has done, there isn't as much cultural momentum to thinking that *slaves are inferior people.* (Well, maybe they got themselves into slavery due to their own vices, but they're redeemable.)
# The Bad News
There is an economy around slavery, which allows for goods and services to be very cheap. Straightaway abolishing slavery makes the costs for goods go *way* up, not to mention the small impact of some slave-masters loosing their jobs. What is an even more concerning prospect is collecting debt. Do you make a [debtors' prison](https://en.wikipedia.org/wiki/Debtors%27_prison)? It's a new, but less terrible, problem.
# A Gradual Approach
This essentially goes from [chattel slavery](https://en.wikipedia.org/wiki/Slavery#Chattel_slavery) to [bond slavery](https://en.wikipedia.org/wiki/Debt_bondage) with some humanitarian rights, trying to utilize the cultural currents which already appear present. I personally would only recommend this course if outright abolition is not an option. (She's a queen-goddess. She can tell people below her to 'just deal' with her choices!)
1. Give slaves rights. Included are: a right to life (including safety from beatings, rape, and "inhumane" treatment); the right to buy their freedom for a reasonable cost through money, a prearranged time, or upon the completion of an event; the right to stay within reasonable distance of their families and to not separate parents and dependents; the right to remain under a master (to ensure protection from abuses to step 2 or 3); and the right to immediately appeal to any judge or enforcer of laws for violation of these rights. After all, if you spent time as a slave, *you* would want some basic rights!
2. Establish that any slave, of any origin, has these rights while within territory controlled by the crown. (This can cause international debacles, sure, but it's a simple law.)
3. All slave owners must register with the crown; who they are, who their slaves are, how much those slaves owe, under what conditions they will be released, and if sold to another, who that other party is. Any violations will result in a very unpleasant penalty, which may include immediate emancipation of those slaves.
Using those terms, "slaves" basically turn into indentured servants. This essentially a compromise between what some potentially influential people want and the queen's will. She could also wait for many years under these rules, and then finally abolish slavery altogether! Sure, [wage slavery](https://en.wikipedia.org/wiki/Labour_economics#Wage_slavery) may exist, but it's better than chattel slavery!
We should also note that views on slavery varied greatly in real history, and were opposed and supported and lacked the binary status of "supported" and "not supported." Some religious leaders (like [Paul](http://gospelpedlar.com/articles/Church%20History/slavery.html)) don't outright condemn slavery, but do advocate for particular behavior on both sides, which can be seen as non-binary actions which move the history of slavery along.
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How I would do it is.
1) Immediately abolish the import of slaves.
2) The sale of slaves to anyone but the crown is prohibited.
3) the crown is obligated to buy them at customary market valuation reckoned at three months before the date of abolition. Declining at a rate of 50% per month for the next year at which time the slaves are automatically manumitted.
4) Anyone found holding slaves after this date will be imprisoned at the pleasure of the crown.
5) Anyone found holding slaves after the anniversary of this date will be executed.
The crown trains the former slaves in basic literacy and a trade and provides them with protection.
This would result in less anger by former slaveholders as they would be reimbursed for their financial loss. The declining evaluation would encourage the to be quick and the graduated penalty gives some allowances to logistics.
My alternate plan would be just to kill the slaveholders and give their property to their slaves. I would be more just but might ruffle some feathers of the landed class.
The training and protection are to prevent jim crow and to give the former slaves a more gradual entry into the ranks of free men.
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Not an answer, but OP wanted me to expound on this
## This could have very long term consequences
What you describe is some what similar to slavery in the south of the U.S. in the 1800s or so. Slaves made up a lot of the population (definitely over 10%), worked in agriculture, and a slave owner owned his slave's children. When the U.S. got an anti-slavery leader, the South didn't wait for him to abolish; shortly after Abraham Lincoln's election, they succeeded from the Union. [This resulted in the U.S. fighting the most powerful enemy in the world, itself.](https://en.wikipedia.org/wiki/American_Civil_War) Needless to say, it was very bloody. Afterwards, slavery was abolished. Some problems:
* People who had lots of wealth had significantly less wealth.
+ To avert this, slave owners either didn't tell the slaves that they were free, or hired them cheaply.
* The South become poverty stricken, as its economy wasn't ready to be slave free. This is still affecting some parts of the South today. The period of trying to resolve this was called the [Reconstruction Era](https://en.wikipedia.org/wiki/Reconstruction_Era).
* To this day, the descendants of slaves are still at odds with the descendants of slave owners. Slave owner descendants still regularly discriminate against slave descendants. Slave descendants want privileges from the government.
+ This is made possible by the fact that slaves and slave owners where different races, and even after the abolishment of slavery, slaves descendants and slave owner descendants rarely had children together. (For application to your magic world, see <http://tvtropes.org/pmwiki/pmwiki.php/Main/FantasticRacism>)
+ Even those against slavery were still were in favor of discrimination.
* A lot of descendants of slaves are still poor today, in part due to inheritance of wealth, but largely due to racism. (These two effects reinforce each other.)
A lot of these problems (but not all) are averted if you slave owners and slaves are the same race, but that is hard if slavery is inherited.
(Also, [the goddess-queen is getting shot](https://en.wikipedia.org/wiki/Assassination_of_Abraham_Lincoln).)
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Historically, non magical realms like the northern parts of the USA found it easy to abolish slavery within a single human lifetime. At the start of our nation, all or nearly all states had slavery. When the urge struck, the usual way of handling it was to set a target date that stated that anyone born after that date would be free, not slave. Thus without taking any assets from a citizen, slaves would vanish from the state.
Similarly, you could set a distance date when any remaining slaves would be freed. This would give anyone plenty of time to sell slaves elsewhere if freeing them was objectionable.
Peer pressure coupled with these laws made it painless at a societal level as long as the proportion of ex-slaves to free is small, even with the racial basis of slavery in the US. The breakdown in the US came when states forsaw that they would have a high to very high level of ex-slaves in their state if emancipation came and no way to get rid of them elsewhere. This was what led to sectional strife.
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For a more historically relevant background, study the progress, costs and consequences of the emancipation of slavery from England and the British Empire from about 1770. The common theme is that it is relatively easy to outlaw when slavery is not a cornerstone of the economy (trading, manufacturing etc.), and extremely difficult when you are dependent on it (such as labour intensive plantations). Doing the maths, your economy benefits from slave trading but only 10% of your population are slaves, and it is not unreasonable to assume a trader would have at least 10 slaves, therefore less then 1% of your population is directly dependent on slavery. You can expect some grumbling by banning it but not enough IMHO to make it an issue.
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I'm trying to setup a non-real scenario that doesn't break suspension of disbelief too much past the original idea. But so long as things keep consistency it should be fine.
So you are flying a fighter plane of sorts (could be current tech, you could opt to choose future tech or old tech for your answer if you believe it's not possible otherwise/believe it is). And suddenly you see/are informed of a ground to air rocket launch from an enemy, towards you of course.
Now instead of a single or a couple rockets headed towards you, you get "enough missiles to blot the sun" heading towards you non stop (or at least an extended period of time), and I want you to fly through.
In case the description is too open still, then let's go with 30 *streams* of rockets firing twice a second (60 rockets a second then) and firing non stop for a whole minute, the rockets don't spread much and seem to keep formation, and as such will fly in a long growing blob like a snake/bee swarm of sorts.
Try to remain IRL tech, but you can use your fantasy if you have a cool idea. For example the idea of a mass of missiles being launched for a single plane is a bit fantastic already. They would probably spread wide to cover as much volume as possible anyway.
I first assume you'd want to fly in a pattern that eases dodging them, you want to fly through, but it may/not be smarter to dodge to the side a bit, so long as you don't do a u-turn and tail it it's ok. Missiles, at least current tech, should have great capabilities hitting you. So they could be made lower tech (to make up for their extreme quantity) in order for you to have a slightly better chance. You could also have a futuristic jet that can actually dodge current missiles if there is no other way around it.
Second idea would be shooting them down, with current tech you got bullets and rockets, with old tech just bullets, future tech you can have anything. Regardless, if you could get one of them to explode, would there be a chain reaction all the way to the launchers? I would assume yes, but I'm not an expert on that, do warheads arm right on launch? or before impact? would an unarmed warhead explode anyway from an explosion next to it? Would the propellant ignite regardless of the warheads and cause big enough explosions for a chain reaction?
In case a chain reaction is unlikely, would the initial explosion disable all missiles on its radius so that you could survive as long as you could keep the explosions going?
Third idea would be turning "invisible" somehow, current missiles search in several spectrums so I assume that's not possible, but older tech? Perhaps they are cheaper rockets or leftovers from past wars. Also since its a mass of missiles I have to assume they don't use their own recon system because they'll be obscured by the missiles in front (or the ones to the side when turning), and instead receive vectors from the missiles at the front or a ground station. Perhaps a way to kill comms briefly would work.
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If there are that many missiles close together, it might be worthwhile to see if there is some way to create a cascade failure.
A counter missile delivering an EMP pulse might knock out enough guidance systems that many of the missiles in the EMP cone fly into each other or fall out of the sky, creating a clear path for your airplane. In an extreme scenario, where the enemy missiles have nuclear warheads, you could launch a neutron bomb and cripple the enemy warheads, with the blast effect punching the physical hole through the missile cloud.
Trying to mess with the conventional warheads or fuel of incoming missiles to make them explode needs a special gadget: If your airplane mounted a megawatt laser with a very fast tracking system and focusing mirror (think of the 747 Airborne Laser Lab fully developed), then the energy of the laser beam might ignite the fuel or detonate the warheads, throwing out clouds of debris which the other missiles fly into, causing them to crash or explode as well.
[Answer]
**Would an unarmed warhead explode anyway from an explosion next to it?**
Since [anti-ballistic missiles](https://en.wikipedia.org/wiki/MIM-104_Patriot#MIM-104F_.28PAC-3.29) exist this is possible in principle. It can be explained in two ways.
(1) The first explosion ignites the payload of the second missile, triggering premature explosion.
(2) The first explosion causes the guidance system of the second to register a target and self-detonate.
For early types of missiles (1) is your best bet. The missile is essentially a gas tank linked to a sparkplug. The spark can equally be supplied by an explosion outside. I'm sure the missile's less sophisticated casing makes that easier. (2) cannot occur because the guidance system only works to aim the missile downwards and measure the distance traveled. The missile does not care if it encounters something before then.
For modern types of missiles (2) is more likely. The ignition mechanism is more protected and probably more nuanced. It might even break rather than detonate if subjected to an external blast. Modern missiles can track moving targets, **and they detonate before making physical contact**. The tracking software might register even an indirect blast from the first missile as having reached the target, and go off on its own volition.
**Modern missiles detonate before making physical contact:**
I cannot stress this enough: This is the main barrier to a 'rain of missiles'. If the missiles get too close to each other they will simply detonate whether or not something is flying through them. You could decide these missiles don't track that kind of way of course, but that would make them pretty ineffective anti-aircraft weapons.
There are also kinetic missiles that don't explode at all. But those are designed to counter other missiles which follow predictable trajectories. They wouldn't work against fighters that change direction to dodge.
[Answer]
There is a classic situation similar to this that we see all the time in films, books, etc. Generally, fly somewhere they can't follow. In space, it's usually an asteroid belt, while in aircraft you dive under a bridge. through a narrow canyon, or somewhere similar. The idea is that you are able to take a route that's only just big enough for you and as a result anything that's just heading directly for you hits the obstacle instead.
[Answer]
**Implosion missile**
Your plane fires a missile that causes implosion at the target point. Many missiles are forced to crash into each other. Others would be pushed away by the explosion of these missiles. You may need to fire couple of them to open a corridor but would work without hand waving.
[Answer]
Use an infosec attack: hack their software to make them steer themselves in the direction you want (i.e. to avoid the incoming plane). For bonus irony/cliche points, turn the missiles back to [hit the place that launched them](http://tvtropes.org/pmwiki/pmwiki.php/Main/HoistByHisOwnPetard).
[Answer]
With current tech, this is not possible.
India has been using their [Shaurya missiles](https://en.wikipedia.org/wiki/Shaurya_(missile)) since 2011. Those missiles can reach Mach 7.5 even in low altitudes. They can also carry various payloads, including nuclear. If you are flying towards one of these at Mach 1, your relative speed will be around a third of the Space Shuttle's reentry speed. If you are 700 km away from them, they'll clear that space in 5-6 seconds; they will be exploding before any counter measures of yours can start working and you will fly though the blast, knocking your plane out of the sky.
And that's just India. China has already shown how they can successfully destroy satellites with missiles; that involves maneuverability and precision on much higher scales.
In the 21st century, the best countermeadure against missiles for aircraft is to not be there.
[Answer]
So... there are a lot of good valid answers here but i'll look at it another way.
For this section lets ignore the missiles will attempt to detonate when in proximity to your Character's Aircraft, or at least the engine exhaust in case of heatseaking.
Anti Aircraft Missiles are Go-Onto Target systems or GOT systems, this means they are guided to their target, this is different from Ballistic or Rockets, both of which fire in a single direction then either exploded or fall in an arc onto their target
In every Go-Onto-Target system there are three subsystems:
* Target tracker
* Missile tracker
* Guidance computer
The way these three subsystems are distributed between the missile and the launcher result in two different categories:
* **Remote Control Guidance**: The guidance computer is on the launcher. The target tracker is also placed on the launching platform.
* **Homing Guidance**: The guidance computers are in the missile and in the target tracker.
I think if there is going to be 60 missiles per second in the air for X amount of time each, then its unlikely that ground based guidance would be able to effectively track each missile while Radar would bounce off the missiles in front off, behind, above below or to the sides of the tracked missile. Very quickly the Missile Tracker would lose the ability to effectively track the missile when surrounded by so many other objects.
So its more likely that the missiles will be **Homing Guidance** with on board guidance systems. why is this important? because Homing Missiles are "easier" to counter than Remote Control Guidance
**But is it possible to fly through a swarm of missiles?**
Missiles leave a cone of disturbed air behind them, which means control surfaces are less effective, so the onboard systems on modern missiles will usually aim to have maximm control until closer to the target, so they would spread out a little, these gaps "could" end up being big enough to fly through but then it wouldnn't really "block out the sun" so basically we need to "make a hole"
*But I want to fly through a swarm of missiles?*
If your fighter was flying at say 600mph (slow for a fighterjet) and the missles were going at 600mph (very slow for a missile) in the other direction then they'd meet at 1200mph, even if the missile didn't explode the damage done due to kinetic energy would likely irreparably damage the plane.
*"Please!!! I REALLY want to fly through the swarm*
Fine, I guess if your plane was nimble enough then its possible that you could but only if there was a straight line through them and also very very lucky, any turning inside the swarm would require superhuman reflexes.
**So how do we make a hole?**
That's simple, that many Homing missiles flying so close together just bank in any direction and when the missiles correct their courses all slightly different from each other they crash together, most likely one or two would have their control surfaces damaged which would put them drastically of course colliding with each other again damaging more and more until they just start exploding all over the place.
Oh you don't want that... ok, then start with current anti missile defense systems, or countermeasures, in jets this is flares, most AAM are heat-seeking and they go after the hot engines, the flares burn hotter than the engines so the missiles go after that, but this would be best if the missiles were fired "after" the plane has flown past... as the flares only burn hot enough to fool the missiles for a few moments.
You may ask why am i going towards them and not having them follow me? well its simple, i can't fly though a swarm that's flying past me can I?
So so you need to fire something ahead of your plane to knock out the missiles ahead of you... fire some missiles of your own, they can be set to explode after a certain distance. which would at least damage the missiles directly ahead of you and hopefully make a hole.
**What about using a Shield?**
No i don't mean the Star Trek Energy kind, i mean shield your plane with something from the missiles, like a bridge, canyon wall, building, hopes and dreams... it s possible, the only problem with them is that the plane tends not to just hide behind them for very long so you'd need to find a lot of bridges etc to take out all the missiles, and again this works a lot better if they are following the plane instead of heading straight for it.
Hmm... EMP? that might work, the problem is that you need to fire this continually around you out to a sufficient distance as to take out the missiles and not have them be in your way either, and EMP Generators take time to charge and then send out the P in EMP, a pulse, not a continual signal. which is what you'd need...
So Shielding yourself probably wouldn't work..., neither would countermeasures... neither realistically would just flying straight through... and neither would EMPs... bugger! For these reasons you need a lot of luck and a big enough hole already... maybe launch a missile or two and then start praying... did i mention how much luck you would need?
**TLDR**
Not really possible... but then again neither is that many missiles being fired at you in the first place so go for gold
[Answer]
**Bootleg turn.**
<https://en.wikipedia.org/wiki/Bootleg_turn>
[](https://i.stack.imgur.com/tUJCh.png)
>
> A bootleg turn is a driving maneuver intended to reverse the direction
> of travel of a forward-moving automobile by 180 degrees in a minimum
> amount of time while staying within the width of a two-lane road. This
> maneuver is also known as a smuggler's turn, powerslide, or simply a
> bootlegger
>
>
>
1: Accelerate towards the missiles. Get going fast.
2: Perform bootleg turn in your jet right before the first missiles hit. Your jet can do this because it is awesome. You continue into the missiles, backwards.
3: Turn jets back on as you are flying backwards. The expanding cloud of gas behind you will blow missles laterally and they will miss you on all sides. You are also decelerating because of this.
4: Once all missiles pass you (they will come close!), you will have stopped and might be starting free fall. Missiles that have missed you will turn towards the direction you were and try to return. The cloud of missiles will all try to come back along the same line. It will be crowded there.
[Answer]
Launching so many missiles is quite odd. Missiles are not cheap, they take effort to craft, take up no small amount of space, etc...
A guided missile using current technology (or even somewhat older tech) is more than capable of locking onto, catching up to, and causing serious inconvenience to your plane.
So why are they launching so many?
1. You are not the target, you are between the missiles and the target.
* Maintain your course heading and speed, do not engage any counter-measures.
* Change your underwear, it will be quite scary.
2. The missiles are unguided, there are no more effective anti-air defenses available. This smells of desperation.
* Fire your own missile directly at the pack, follow in its wake.
* Any short range targeting on those missiles will likely lock-on to the missile you just fired.
* Otherwise your missile will lock onto theirs and explode clearing a flight path.
* You may want to fire more than one missile with a delay between each.
* Follow up by using forward mounted machine guns (if your fortunate enough to have them).
* Once through the pack, deploy any flak or rear-mounted anti-missile ordinance, should one missile lock-on, turn around, and track you.
It will look scary close, or heroic certainty depending on what you want the outcome to be.
[Answer]
**Go into virtual 'reverse'**
Turn around and match speed with the missiles. Reduce speed slightly so that they are overtaking you slowly. In effect you are now reversing through the onslaught but with plenty of time to react. Of course this requires a mirror or you turning to look behind you or maybe your plane has cameras to show if another fighter is on your tail.. It also requires the co-ordination to 'reverse' a plane but of course fighter pilots are selected for this sort of ability.
[Answer]
Your question implies true missiles, which are guided to go after a target. This is opposed to rockets, which are unguided. I point this out because it is unheard of to launch that many missiles, because they are typically far too expensive to be wasteful with. Doing this with rockets is more reasonable. Doing it with bullets is common.
As for whether you can fly through them? Well, I'll put it this way. A F-22 can be [loaded out](http://www.aerospaceweb.org/question/planes/q0105.shtml) with 6-14 AIM-120: 6 in the internal bays plus 8 more on pylons if stealth is not an issue. This is considered sufficient to enter a hostile region and combat enemy aircraft who are trying to shoot you down. Your barrage fires 5-10 times that many *every second*. I can guarantee you that if a small number of missiles offers a reasonable probability of kill, your aircraft is hosed facing 100 or 1000 times that many, especially if it is getting close enough where "fly through a rain of missiles" is an accurate phrasing.
As for fratricide issues, I'm assuming your opponent didn't go down to the Home Despot and buy whatever missiles were in the bargain bin. If they're firing missiles in this rapid fire (belt fed?) manner, they've picked missiles which have acceptable fratricide behaviors. Militaries are not known for slitting their own throat by buying several billion dollars in missiles rather than buying millions of dollars worth of them and avoiding the fratricide issues.
As for stealth? Well, if they actually put up a *wall*, there's no use for stealth. It doesn't help to be invisible when your opponent literally puts up a brick wall for you to run into. They don't need to see at that point. However, if there's a bit more airspace between them, you'll find that radar still functions in that environment. For one thing, radar is astonishingly good at filtering out objects by velocity. Relative velocity comes across as a Doppler shift, which is very easy to detect. Your pilot is the only object coming towards the missiles. All of the missiles are all going roughly the same direction.
] |
[Question]
[
I hope my question isn't too vague or broad. It's a follow-up to [this one](https://worldbuilding.stackexchange.com/questions/3054/can-a-genetically-modified-human-breathe-something-other-than-earths-oxygen-nit).
So, we have a human (genetically modified in order to support life on another place, from previous question) on an alien world - specifically a male human. Assuming that nothing on his sexual organs has been changed, **is it possible or even plausible to have the alien mate with human in order to assure the alien's survival as a race?** The result offspring would have none of the human's features, only the alien's.
[Answer]
The simple answer is "no", however that's not a very interesting answer, so lets turn it around in this case.
If the aliens had a reproductive system very different from our own then it would be possible to have the result you are looking for, I'll give a few examples below. It should be pointed out though that anything a human male can provide a reasonably advanced alien species would be able to do artificially so there is no reason they would "need" the humans unless their technology level was lower than our current present day knowledge and certainly no more advanced than us.
**Catalysis**
Perhaps the female's eggs are capable of developing without actually being fertilized but the development process is catalysed or fed by certain sugars present in the male semen. Human semen contains enough of the relevant sugars to trigger the process of development.
Equally maybe again the eggs do not need fertilization and the act of intercourse by itself is enough to catalyse the process.
Note that in both these cases the new child would most likely be essentially a clone of the mother, genetically nearly identical.
**Joining**
The [Asari from Mass Effect](http://masseffect.wikia.com/wiki/Asari) are all female and can mate with any other species and gender. When they do so the person being mated with contributes in some not-very-well-specified way to the child although the child remains completely Asari.
**Modification**
The species itself could have been heavily modified to allow cross-species breeding. For example in the Culture novels most of the members of The Culture have heavily customized and enhanced bodies. This allows them to change Gender, Skin Colour and Build (including adaptation to different levels of gravity) pretty much by willing it to be so and then waiting for a few weeks while the new changes grow through. This also allows them all to be fertile with each other even when different species originally, their modified reproductive system is able to use and incorporate any incoming genetic material, even when it would not normally be compatible.
[Answer]
From the point of view of science, it seems very implausible. There are quite good reasons why lifeforms based on carbons might share the RNA/DNA-mechanism to store their genetic code (stable molecules from materials abundant in space, except for [ribose](http://en.wikipedia.org/wiki/Ribose)). Even some of our [base pairs](http://en.wikipedia.org/wiki/Nucleobase) could be used in alien species, since among many possible base pairs, cytosine, uracil, adenine, guanine and thymine are exceptionally stable with respect to harmful UV radiation and therefore a good molecules to use. But the [genetic code](http://en.wikipedia.org/wiki/Genetic_code), the translation table which tells the cell how to translate the DNA or RNA into proteins from which the bodies are built, is very random and would be almost certainly be different. In other words: DNA of both species would be mistranslated in the breeding process and no offspring could be born. Pleasant side-effect is, that we can very probably be never infected by an alien virus, since our cells will not provide the building blocks it asks for.
*Note:* Even with identical genetic code, sufficiently different species will not produce offspring. Any independently evolved aliens would be genetically much further than, say, alligators and horses. I pretty much doubt there could be offspring of an alligator and a horse, even if they share (almost) completely the same molecular biology.
### Genetic code - short explanation:
*From Wikibooks: [An Introduction to Molecular Biology/Genetic Code](http://en.wikibooks.org/wiki/An_Introduction_to_Molecular_Biology/Genetic_Code)*
In the cell nucleus, DNA is used to store the genetic data. They are used in a following way: DNA gets transcribed into RNA and RNA is later translated according to the table of genetic code. Each three letters of the RNA code information about one amino-acid, which is used as part of the new protein. (Proteins make our bodies, but not necessarily alien bodies - then, the breeding would be completely out of question.) The table is quite universal for most of the organisms on Earth, but it evolved pretty randomly and it would take immense coincidence that they would be mutually compatible.
[Answer]
I am assuming that you are looking for a contrived reason that this would work. Scientifically it shouldn't but that is ignored in SciFi enough you don't really need a reason. I also assume that the species is completely alien (not ancestory with humans) yet phycially able to have sex due to convergent evolution or some hand waving. That being said there is one way and it relys heavily on the fact that we are discussing how to write fiction:
The mating has nothing to do with reproduction. Sex is not just about reproduction in our society. If that is the case with the aliens too it might be an important element in a story.
Say we have enough technology that we are going to nuke the living hell out of the aliens if they kill you. The females are dominant over males in the culture. The Queen decides she doesn't like you and is to have you killed. The princess however wants to \*\*censored\*\* and as a result takes you as her mate. The Queen doesn't kill you at the risk of upsetting her daughter. You live. So do they.
Say the species can exchange antibodies through the mating process. They are all dying of some bacteria you brought with you. You find that they can assimilate your resistance to it by intercourse and I don't mean talking. You start making your way througb the females, they work through the males, etc. I probably wouldn't read that book but it serves your purposes.
If it needs to be about reproduction: The species has eggs that can germinate using its own genetic material if the male's in incompatable. It is, however, an induced ovulator. For example, male cats have spines which scrap the insides of the queen (in this case the term for an unspayed female cat) to ovulate if she is in heat. If you cannot provide genetic material but some detail of you activities induces ovulation, you can cause the alien to get pregnant with one of her own kind. If you have a few of their females, you can mate with them until a male is born to allow actual sexual (as opposed to asexual) reproduction again.
[Answer]
## Meiosis
Human reproduction is a complex dance, a gamete cell splits producing two complete copies , then each of these cells splits again, with half of the DNA moving to one side, and half to the other. At this point the DNA is shuffled around a bit, producing two partial complements of DNA, the cell splits, and we get 4 eggs, or 4 sperm.
## Fertilisation
When a sperm meets an egg, it's 50% complement of DNA is matched with the egg's complement, giving us a new, genetically unique individual.
## Genetic machinery
Of course, this DNA is useless without the specific machinery to read it. If I gave you a flash drive containing a bunch of encrypted data, but you had no decryption software to read it with, or even a computer, or even electricity, that data would be worthless to you.
A human cell is a vast factory able to read data from the DNA and convert it to proteins which then fold in very specific ways to create enzymes. Seriously, it's awesome. Use different machinery and you'll get junk, just a mess of dead protein that doesn't do anything.
Moreover, the proteins produced are themselves molecular machines, or components thereof, they probably would not have the same effect. Imagine putting a fast washing machine motor inside a laptop and expecting it to speed up the processor. It's just not the same piece of kit, the components can't work together like that.
Even more than this, these molecular machines need to have many other equally complicated machines around them in order to work. Imagine putting a pie machine in the middle of a car assembly plant. It wouldn't do anything, there are no raw ingredients being supplied to it, there's no oven to bake the produce, no conveyor to move the pies to the packaging facility, no delivery lorries waiting outside. It just wouldn't do anything.
## Alien procreation
So we have a problem. Since standard terran sexual fertilisation requires two exactly matched complementary sets of DNA, and a very specific set of molecular machinery and decoding equipment to correctly read and interpret the data, and then a very specific environment in which the molecular machines you've produced can interoperate, it would be difficult for an alien to procreate with a human in the standard way.
This doesn't mean it's impossible though.
## Possible Solutions
DNA is expressed within a human, the human itself is a DNA decoding machine. Perhaps the alien can make use of the human's own expression of it's DNA.
Perhaps information is transferred in some other way unknown to us. Some holographic information is collected, allowing the alien to mimic the structure and form of the human without directly reading the DNA as with Ridley Scott's Alien, which mimics the structure and form of it's original host to gain a survival advantage.
Perhaps the alien has the ability to mimic the machinery of a human cell somehow, maybe by absorbing a complete cell, or by absorbing two complementary cells creating an embryo out of human tissue and then manipulating it somehow to produce a hybrid.
Perhaps the Alien is able to modify the development of a foetus, changing it's gene expression in clever ways.
Perhaps it taps into some other form of information exchange unknown to us.
Perhaps it's only interested in some specific feature of our cellular anatomy, such as our ability to metabolise glucose, or the general structure of our brain.
[Answer]
Yes this is absolutely plausible there are organisms right here on earth whos method of sexual reproduction is the exchange of dna via touch/contact not even requiring sophisticated sexual organs now If the aliens had this method they could essentially touch you to procure genetic material and after the first genisis there may be humanoids that have false sexual organs or proto organs that could still be usefull in reproduction as their skin or outer membrane allows for dna exchange regardless. Now this could have been an evolutionary trait that was passed on for survival of the species by way of essentially becoming their predators whilst retaining some of their original primal attributes. Just a thought....
[Answer]
No, absolutely not. There is literally not a single possible way it could happen. The alien evolved on a completely different planet, even if it looks similar, it is genetically further away from a human than any living thing on Earth. It might not even have DNA, or chromosomes, or egg cells.
] |
[Question]
[
**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
Suppose at a point in the earth’s future, a superstructure has been built at the northern 45 parallel. 50 kilometers above sea level, a large array of mirrors has been built. The mirrors are articulate, such that they always reflect light directly “downward” toward the base of the structure. How long before sunrise and after sunset would the mirrors be illuminated at the equinoxes and the solstices?
Context; I’m working on a society that lives in the shelter of biological technologies they have long since lost the keys to. I’ve run into a spot of math that is a bit beyond my level- the sunrise equation! Putting my head together with a friend, we reached crude numbers of 41 minutes at winter solstice and 68 at summer, but neither of us are astrophysicists, and I don’t totally trust our calculations. Any help would be appreciated!
[Answer]
Here is an approximate geometrical solution.
[](https://i.stack.imgur.com/2DUIM.png)
Suppose your position at height
$h$ above the Earth's surface is $O$, the
center of the Earth is $C$, a point of the Earth's surface that you
see at the horizon is $B$, and the radius of the
Earth where you are is $r$. Then the sine of $COB$ is $r / (r + h)$, so if $A$ is a point on the "normal" horizon (perpendicular to the zenith) directly
above $B$, this will also be the cosine of the
complementary angle $BOA$. Therefore, the horizon has a dip angle
of $d\_1=\arccos (r/(r + h))$ below the "normal" horizon.
Projecting these points to the celestial sphere, if the center of the Sun sets below or rises above
the dipped horizon at $B$, the north celestial pole is at $P$,
and the direction towards north on the normal horizon is at $N$, then
$BAN$ and $ANP$ are right angles, $AB$ equals the dip angle ($d$ say),
$NP$ equals the latitude $L > 0$, and $PB$ equals 90° minus the Sun's declination ($90^\circ - \delta$, say.)
[](https://i.stack.imgur.com/zdOp5.png)
Solving using the spherical laws of [sines](https://en.wikipedia.org/wiki/Law_of_sines#The_spherical_law_of_sines) and [cosines](https://en.wikipedia.org/wiki/Spherical_law_of_cosines) gives
$$
\cos BPN = \frac{\sin d + \sin L \sin \delta}{\cos L \cos \delta}.
$$
To find the dip angle
$d$ for a sunrise or sunset at the Earth's surface, you can use that
the Sun's angular radius is approximately [16 arcminutes](https://web.archive.org/web/20100527142627id_/http://education.gsfc.nasa.gov/eclipse/pages/faq.html), depending on where the Earth is in its orbit, and
also apply a refractive correction of about 34 arcminutes
([[1](https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1776&context=etdr)], §1.1, p. 2.) This gives approximately $d=d\_0=50^\prime$. To find the dip angle for a sunrise or sunset high above the surface,
you could just take $d=d\_0+d\_1$ (but see below.) The difference in times
then will be about the time it takes the Earth to rotate by an angle of
$$
\alpha=
\arccos\frac{\sin d\_0 + \sin L \sin \delta}{\cos L \cos \delta}
-
\arccos\frac{\sin (d\_0 + d\_1) + \sin L \sin \delta}{\cos L \cos \delta}.
$$
Plugging in values of $h=50 \ \rm km$, $r=6367.49 \ \rm km$ at $45^\circ N$,
$L=45^\circ$, $d\_0=50^\prime$, and $\delta=\pm 23^\circ 26^\prime$ for the
solstices or $\delta=0$ for the equinox gives estimates of
$$
\begin{array}{cl}
\alpha=13^\circ 15^\prime & \hbox{for the summer solstice,}\\
\alpha=10^\circ 10^\prime & \hbox{for the equinox, and}\\
\alpha=11^\circ 36^\prime & \hbox{for the winter solstice.}
\end{array}
$$
Converting these to times gives approximately
$$
\begin{array}{cl}
53 \ \hbox{minutes} & \hbox{for the summer solstice,}\\
41 \ \hbox{minutes} & \hbox{for the equinox, and}\\
46 \ \hbox{minutes} & \hbox{for the winter solstice.}
\end{array}
$$
A major source of error in these estimates is the refractive correction.
According to [[1](https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1776&context=etdr)], §1.1, p. 2, it's conventional to
use a correction of $34^\prime$, and this is what's often
used in published tables of sunrises and sunsets, but it's not always
accurate and can lead to errors of several minutes. The correction will surely also be different 50 km above the Earth's surface. [[1](https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1776&context=etdr)] gives some more accurate refractive models, which might help to compute a better estimate. In its article on the [sunrise equation](https://en.wikipedia.org/wiki/Sunrise_equation), Wikipedia suggests that you take
$$
d\_1=2.076 \sqrt{h},
\qquad \hbox{if $d\_1$ is in arcminutes and $h$ is in meters.}
$$
Using this estimate would give
$$
\begin{array}{cl}
58 \ \hbox{minutes} & \hbox{for the summer solstice,}\\
44 \ \hbox{minutes} & \hbox{for the equinox, and}\\
50 \ \hbox{minutes} & \hbox{for the winter solstice,}
\end{array}
$$
but I doubt that this formula is intended to be accurate at a height of
50 km.
**Addendum**: Here are some graphs showing how the time varies
with the latitude and the Sun's declination. They are computed
using the formulae above and $d\_1=\arccos (r/(r+h))$.
[](https://i.stack.imgur.com/OZLNW.png)
[](https://i.stack.imgur.com/VuSh6.png)
In the first graph, the declination where the time is smallest,
which, interestingly, is not zero (unless you are at the equator), is marked with an "x".
References [[2](https://ui.adsabs.harvard.edu/abs/2000Obs...120...62M/abstract)], [[3](https://ui.adsabs.harvard.edu/abs/1896PA......4..148H/abstract)], [[4](https://ui.adsabs.harvard.edu/abs/1896PA......4..211H/abstract)], [[5](https://ui.adsabs.harvard.edu/abs/1896PA......4..252H/abstract)] and
[[6](https://ui.adsabs.harvard.edu/abs/1897PA......5..257H/abstract)] discuss the similar problem of finding when the shortest
twilight occurs.
References:
[[1](https://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1776&context=etdr)]: "Evaluating the Effectiveness of Current Atmospheric Refraction Models in Predicting Sunrise and Sunset Times", Teresa Wilson, Ph. D. thesis, Michigan Technological University, 2018; DOI 10.37099/mtu.dc.etdr/697.
[[2](https://ui.adsabs.harvard.edu/abs/2000Obs...120...62M/abstract)]: "The shortest twilight", B. G. Marsden and R. F. Griffith, *The Observatory*, Feb. 2000, vol. 120, pp. 62-66.
[[3](https://ui.adsabs.harvard.edu/abs/1896PA......4..148H/abstract)], [[4](https://ui.adsabs.harvard.edu/abs/1896PA......4..211H/abstract)], [[5](https://ui.adsabs.harvard.edu/abs/1896PA......4..252H/abstract)], [[6](https://ui.adsabs.harvard.edu/abs/1897PA......5..257H/abstract)]: "The Twilight", Orrin E. Harmon, *Popular Astronomy*, Sep. 1896, vol. 4, pp. 148-154; Oct. 1896, vol. 4, pp. 211-214; Nov. 1896, vol. 4, pp. 252-258; and Sep. 1897, vol. 5, pp. 257-263.
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From a height of 50 km, the horizon is at about 800 km. At 45 degrees latitude, 800 km is about 10 degrees of longitude. The solar time 10 degrees of longitude away is about 40 minutes ahead or behind local time. (Because the sun moves about 15 degrees per hour.) Overall, the mirrors will become illuminated about 40 minutes before local sunrise, and will remain illuminated about 40 minutes after sunset.
(Because most of the time the sun does not rise and set true east and true west, the extra illumination time will be a little longer than the time difference corresponding to 10 degrees of longitude. I compensated for this assuming an extra 1 hour 30 minutes instead of 1 hour 20 minutes.) (Hat tip to @Litho.)
At equinoxes, the mirrors will be illuminated for about 13 hours and 20 minutes, with 10 hours 40 minutes of darkness; at the summer solstice the mirrors will be illuminated for about 16 hours 30 minutes, with only 7 hours 30 minutes of darkness; and at the winter solstice the mirrors will be illuminated for about 10 hours 30 minutes, with 13 hours 30 minutes of darkness.
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See also the [Znamya mirror](https://en.wikipedia.org/wiki/Znamya_(satellite))
Not a direct answer to your question (sorry) but it would be easier to stick a mirror in LEO than at 50 Km. As a solar sail, it could be stable at LEO, or propel itself higher. If you want technology that the present people cannot reach, that would seem to fit.
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It is not uncommon for some fantasy and RPG's with a modern setting to boost their melee weapons with electricity. However some people think that such modifications won't really improve the killing potential of the melee weapon.
My question: how would you design an electric melee weapon designed to enhance its killing power?
Some considerations:
* cattle prods are designed to hurt but not permanently harm the target in an attempt to make it move to the desired direction. They are no good example of what electrified weapons designed to kill can do.
* a taser is designed as a less-than-lethal weapon meant to incapacitate the target. It is not a good example of what an electric enhancement designed to kill can do.
* just like a sword will rarely kill on the first blow, the purpose of the electric modification is to significantly increase the chances of a kill, not to kill with every single hit (but if that is possible, go for it).
* the weapon can at maximum gain 10% extra weight from the modification.
* for ease of answering, I'm assuming a spear, a mace and a 70cm long sword of your choosing as modified weapons.
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> a taser is designed as a less-than-lethal weapon meant to incapacitate the target. It is not a good example of what an electric enhancement designed to kill can do.
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Tasers are less-than-lethal, but because they have been designed so as not to use frequencies and waveforms that are demonstrably dangerous. It is entirely possible to make a taser-like device that is explicitly intended to eg. cause a heart attack.
The actual problem there is that it doesn't work instantly... you'd need to form a circuit with the victim, and then run a current through it for some period of time (at least a couple of seconds) so as to induce fibrillation. You could use a melee weapon to connect the probes to a target, but really you'd be better off using a ranged weapon.
What you need is something that works over very short timescales. Instead of using clever waveforms to stop the victim's muscles working properly, just use brute force... a short but very high power pulse that's intended to vaporise a small portion of the target. It doesn't operate continuously, but has some kind of ultracapacitor that is discharged on contact and charges continuously when not shorted.
The basic shape would probably be something like a mace or plain baton. The business end would be a pair of electrodes, spaced far enough apart that they don't arc when energised. You might have several pairs allowing for strikes with the side as well as the tip of the device, for example. The electrodes would probably be notched and carefully fed from a spool, so that if you accidentally welded the end of your shockrod to something (like a bit of armor, or another weapon) you can break it away without damaging or losing it.
On contact with something, there will be a bang and a flash. It might burn a hole in skin or clothing.
Back in the early noughties there was a US military project called the [pulsed energy projectile](https://en.wikipedia.org/wiki/Pulsed_energy_projectile) (which wasn't a projectile):
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> laser pulse which ablates the target's surface and creates a small amount of exploding plasma. This produces a pressure wave that stuns the target and electromagnetic radiation that affects nerve cells causing a painful sensation. The technology can be used as a lethal weapon.
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Now, that plasma doesn't have to be generated by a laser... the electrical discharge from the shockrod will work, too. This means that even if the impact doesn't contact flesh, the electrical fields around the small plasma fireball can still cause pain and muscle spasm... potentially even causing heart disruption. Thick insulating or conductive armor isn't necessarily going to save you here, as you can still be beaten down whilst wearing it. If the weapon was more like a mace with a knurled or spiked and weighted head there's scope for beating through softer armor and crushing some kinds of harder armor. Tough [trauma plates](https://en.wikipedia.org/wiki/Trauma_plate) would probably keep the wearer protected from impacts, but they can't be all enclosing and probably can't protect against the debilitating electric fields.
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# Electroshapable material
As it's about fantasy we can go a bit out of bounds. Using batteries and such to just up the voltage and ampere can do the trick, but seem single trick ponies that are limited in repeatability if at all. Another idea I had was fractal burning. With an electrode on a wire that flips over the target to make internal fractal burns you could do big damage, but the power needed would already be a weapon itself (besides definitely violating many Geneva conventions). I realised most if not all electrical methods would require a voltage and ampere that it would already be dangerous on it's own and likely unpractical for it's power requirement. So I focused on the weapon itself.
Electroshapable material can be used in many ways. In a fantasy setting one can argue that the electricity shapes the material in such a way it'll become unusually sharp. Depending on the shapable material not a lot of current is required.
If magical thinking with sharpness goes to far, we can use it differently. Bash someone with a mace and the low voltage circuit closes. This causes spikes to form from Electroshapable material, adding some damage if it can penetrate armour (which maces aren't designed to do). The hilt can also extend during the swing, using leverage to impact harder.
Spears can have this with a thrust. During the thrust the material will extend under the electricity. It'll extend the spear for extra reach and power. The material can be in the shaft and not the point.
The hilt of a sword can also extend, allowing for different methids of attack. An example can be a short spear configuration.
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There's a reason we don't use electric weapons as a main weapon. In a world where electric weapons are common, people would wear armor resistant to electricity, and a common material that is resistant to electricity is leather. It's not that hard to make taser proof armor. Just wear thick clothes.
As such, each weapon will probably be designed to penetrate armor with a bladed weapon or find gaps in armor and deliver a big charge.
I would probably use something like [a body clip](https://en.wikipedia.org/wiki/Body_cord). In fencing we don't like to stab people with sharp weapons as they'd die, so we use a circuit where when the edge touches someone, an electrical signal is sent that triggers a hit.
You could rewire this so that it was set up to deliver a shock. You'd have wires running along each weapon, and when the weapon hit it would deliver a nasty electrical shock.
Batteries are bulky and you probably want a lot more than 10% weight. As such, you could have the wires go up your shirt to a pack you put on your back. That way the actual weapon only has the weight of the wires, and you can move it almost as fast as a normal weapon.
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# Ancient Weapon Update
Ever heard of a macuahuitl? <https://en.wikipedia.org/wiki/Macuahuitl> This was popular among indigenous people of (now) Mexico and South America. It's somewhere between a mace and a sword: carefully arranged bits of sharp rock embedded in a stick. Modern materials could update this to make a more deviating, electric, anti-personell weapon.
For energizing: each of the blades could be made of metal and act as a "plate" of a capacitor, allowing a shock to be delivered when two "plates"/blades make contact. If only one blade makes contact, the electricity may travel through the target to ground. Both of these behaviors can be desirable. (Bonus: modular blades make repair and sharpening easy!)
This shock need not be lethal in itself: it merely needs to distract or stun the enemy for a short time. Fencers and martial artists know that even small distractions can be the difference between beating the enemy and being beat. Should the target spasm or be distracted by an arc, this could open up the opportunity for a follow up strike.
Armored opponents or opponents who block still run the risk of being shocked, as any electricity from this macuahuitl will attempt to "go to ground", potentially right through their bodies! As stated before, this could cause them to spasm, giving an opening for another blow.
Obviously, the main counter to any electrical weapon is to simply be non-conductive. Polymers and composite shields would be required to prevent most effects of this electricity. This could be as simple as a wood shield (or clear riot shields), but a heavy macuahuitl could penetrate more than a simple mace or sword.
# What About Weight?
Additionally, the overall weight of a weapon takes a back-seat to the balance of the weapon in terms of "performance". Obviously, there are limits here on overall weight. Too heavy and it is too slow for combat. Too light and it is difficult to do harm. Hand weapons within these bounds can sit somewhere on a spectrum from "be fast" to "hit hard".
Embedding batteries into the grip/hilt/pommel would likely cause the least amount of problems for weapons in the "be fast" end. (Spears, thrust-optimized swords would fall into this category.) More batteries, and more mass away from the hand would help the "hit hard" kind of weapon. (Maces, clubs, cut-optimized swords). This is a matter of personal preference, user strength, and weapon design.
Macuahuitls, as far as I can tell, are a bit closer to cut-optimized swords. Placing batteries near the hand and into the body of the weapon would be ideal, although one would have to be careful to design proper covers which can take a beating.
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As other answers have already established, a strong enough current would kill a person, if kept up for some time.
The thing is, most of the melee weapons are not designed to keep a prolonged contact with the flesh of the attacked. They are supposed to cut, stab or crush, with only a moment kept in contact.
The weapons that are supposed to stay in the wound are mostly thrown ones - arrows, javelins or harpoons.
The only group of weapons that would profit from the ability to deliver a lethal electric shock would be rope or chain based - whips, ball on chain, or something like japanese kusarigama. You tangle your opponent with it, catch his arm, or even a sword, an then trigger an electric shock, killing him.
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**Vibroweapons.**
[](https://i.stack.imgur.com/XQuKl.png)
<https://www.youtube.com/watch?v=R35MvOs9nEU>
Usually when I learn something is in Star Wars I group it with blasters and Wookies: fun fake stuff. But vibrating knives are real and they really work.
<https://www.sonics.com/site/assets/files/Ultrasonic-Food-Cutting-Technology.pdf>
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> How Ultrasonic Food Cutting Works and Why You Should Consider It
> Ultrasonic food cutting is a process utilizing knives that vibrate at
> high frequency. Applying ultrasonic vibration to a cutting tool
> creates a nearly frictionless cutting surface which provides many
> benefits. This low friction cutting surface can slice a multitude of
> food products cleanly and without smearing.
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An electric motor which rapidly vibrates a blade allows it to cut more easily. If you want to augment cutting weapons in your world, adding an electric vibrator would be a realistic way to do it.
Don't tell any Mandalorians that I said any part of them was realistic or you might hurt their feelings.
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## Frame Challenge - Lethality is not a Problem
If you hit someone with a melee weapon, it is every bit as fatal as shooting them. For an armored opponent, some melee weapons may actually be *better* - for someone wearing a ballistic vest, a 9mm round to the chest is likely *less* deadly than a mace blow to the chest.
## The Problem is Getting the Hit!
The real issue with melee weapons in modernish combat is closing the distance. Someone can raise their gun, sight down the barrel, and fire a **lot** faster than their opponent can run 20 meters and swing their blade.
So use your electric mods to solve that problem.
## Potential Modifications
Anything that interferes with target acquisition would be a good mod. A mod that shines a bright light at any face it identifies, or a mod that uses a pulse of directed sound to disrupt someone's equilibrium would both be useful.
Likewise, something that creates a false target would be good - you could have a small drone that attaches to the tip of your mace, and lights up and takes flight on command. It doesn't have to actually attack the enemy - just create motion and light to draw the eye and prevent them from shooting while your fighter closes the distance.
Finally, anything that makes the melee fighter faster is a good mod - maybe the weighted end of the mace is a giant battery, and it gives a jolt to the combat suit that lets it move faster / hit harder on command. This would let you close the distance more quickly AND be more likely to kill someone through their armor.
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Related to [this](https://worldbuilding.stackexchange.com/questions/220815/how-to-encourage-education-and-an-atmosphere-of-respecting-knowledge-and-critic/220840#220840) question: After the main character united the seven clan into a Soviet-esque nation, education is introduced and critical, rational, and independent thinking is introduced to these seven warrior races. At the foundation of the nation, MC runs the nation as a paramount leader, assists by a council made of the Party Cadres (the foundation member of the Party, coming from the top echelon of each clan). MC is well-respected by all of the citizens because the MC gains the leadership of each clan fair and square and MC turn the nation from an early 19th century nation all the way into early 20th century in twenty years. But after a few decade, advocation for democracy starts to emerge from the young adults and people dissatisfy with the Party's policy being conservative and and the old ruling/social structure inadequate for the new world--because human nations are advancing too. After an incident, MC realized that grave mistakes are being made and a new government structure is needed for this nation (this is a character development plot). But how could the MC convince the Party Cadres to give up the power they once had without triggering something like the dissolution of Soviet Union or having tanks running over protesters?
Edit: The Party Cadres dont have inherent problem of loving power. They respect strength and believe that they are doing what is best for their nation. It is about the same sort of situation--in a more ideal way--as the 1989 Democratic movement in China. Basically, how to prevent the conservatives in the Party Cadres from anger overload and call in the tanks and convince them that they are wrong and the Party needs new Blood. Once again, they are not glory hound or power hungry.
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Other answers have suggested revolutionary or violent solutions, and that makes a lot of sense because that's the most common way to replace ruling elites in human history. However there are a few counterexamples of more or less pacific transitions worth looking:
* Britain in the XIX century. It started the century being a very restricted kind of democracy, with a very small electorate and with rigged elections dominated by an even smaller a powerful elite, and [successive reforms](https://en.wikipedia.org/wiki/Reform_Act_1832) transformed it in an actual democracy.
* Japan after the Meiji revolution. In the Meiji revolution an alliance of feudal lords overthrew the central government (the shogunate) but then the new government convinced those same feudal lords to give up their power to the emperor.
Faced with similar challenges, elites in other countries and other historical moments have often tried to resist change, just to delay their fall and make it worse. In those two examples, the elites gave up some power in an unsustainable system to remain among the elites in a new situation which was more sustainable and stable.
Then the keys for such a change in the OP's society are:
* Clan leaders should be convinced that keeping the current situation is likely to lead to a revolution in the mid term, or at least to some downfall that would endanger their standing.
* Clan leaders should see a desirable place for them in the new order. Maintaining some type of prestigious honorary nobility for them may help, but allowing them to keep economic power is even better. Japanese daymios became the Meiji nobility, British lords stopped being able to rig elections but remained rich landlords.
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Two thoughts:
* Elections at the top, then expand membership.
Many communist parties learned the hard way that a single leader can be deadly for the people just below them. A Stalin or Mao fears rivals and lashes out. So they learned the benefits of **collective leadership**. A junta, not a dictator. If your character is sufficiently certain of the adoration of the elites, start holding elections for the *chairmanship* of various levels, while still controlling *membership*. Require a supermajority for the chairmanship to encourage coalition politics. Repeat a few years and watch the developing factions. Then allow elections to the *membership* of those boards. A proportional system to encourage small factions and coaltion-building.
* Control candidate lists, allow free elections.
Allow the people a choice in their leaders (either truly free or at least mostly free), while maintaining party control of the candidate selection. Only party members in good standing can run for the town council, only graduates of the basic course at the party school can run for the district council, only graduates of the party university can lead a province.
Compare both China and Iran.
Either way, start slowly and allow the existing cadres to transition from one system to the next.
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## Just execute them
The nice thing about being a Soviet-style head of state is that if you don’t care for how someone in the party behaves, and you’re above them, you can just have them executed. And their replacements. And theirs, until the right people are in place
A show trial with a confession extracted by torture will be helpful for maintaining a semblance of legitimacy.
See Stalin’s [Great Purge](https://en.m.wikipedia.org/wiki/Great_Purge) or Mao’s
[Cultural Revolution](https://en.m.wikipedia.org/wiki/Cultural_Revolution). Mao’s model will be particularly handy, since it exploited the very radicalism of youth you are trying to sate.
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In most cases, people who have power do not give up that power without a struggle. (Just try to take the car keys away from an elderly relative.) Attempting to force the issue will only make the struggle bigger and messier.
The best way is to give them a new position with the semblance of greater power, but actually has less. Give them a position with a lot of pomp and ceremony that has them going around the countryside talking about the good of the country. At the same time, give the new structure more power. (So, instead of taking the car keys away directly, provide a ride service with the image of riding in a limo with a driver. "We are upgrading your ride.")
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Start with elections for local officials. Do it for something like mayors, governors, and the like, then work up to positions with more power over several years. By the time you hit about 50% ([WAG](https://www.quora.com/Is-a-wild-ass-guess-a-real-term-or-a-joke)) of the government (total), the ball will be rolling and unstoppable.
Citizens will see how much good the elected officials are doing and how much they are being held back by the unelected officials. The citizens will also see how easy it is to get rid of officials who aren't doing good. This will snowball and there will overwhelming support for converting the remaining positions to elected officials.
Anyone in power and not concerned with keeping it will understand how well this is working and will be more willing to let go of their power knowing that capable hands will take over, and knowing that power hungry individuals who go against public progress will be removed or otherwise curtailed before they can do any actual damage.
It's not just about giving up power, it's also about making sure that their replacements have society's best interests in mind, rather than their own pocketbook or desire for power.
This is sort of like a "real world" example of what writers are always told about how to write stories: show don't tell. You sometimes have to show people that something will work before they will believe or understand it'll work.
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# Make a democratic presidency.
Military dictatorships are loathe to give up their power, but they also often fuck up and run out of money. Running a government is hard, and the military is often pretty bad at it. In the same way though, they don't want a bunch of civilians defunding them and stopping them from doing what needs to be done. As such, they want a veto.
[This is very common.](https://ideas.repec.org/p/hhs/iuiwop/1194.html) as a transition. They can have civilians run most of the government, while a military leader can become the president and ensure that the military is well protected and shielded from civilian incompetence.
As such, point out the many failures they had, and the disasters that happened, and explain that the young need to have a voice. Set up a democracy where the military still has a lot of power and influence, but where the people can also push policies and ideas to help boost economic and cultural growth.
This has happened often [irl](https://www.youtube.com/watch?v=q64U8vgYGyc) with the cooperation of party elites. Leaders do generally want the best for their people, and any military nation inherently operates on consensus. If everyone who might fight feels they have a voice they'll be more willing to fight and be strong together than if they feel they are ruled by old out of touch people, and if the old and out of touch people have some degree of authority they'll be sated.
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## Leaders are always power hungry, there is no exception
Throughout history, it has always been the most ambitious people who have risen to power. Not the smartest, not the kindest, not the most qualified... to take one of those limited seats of power in your society, you must want it. Why you want it varies, but people who don't want it never get it. Even hereditary leaders are known to abdicate when they do not want that power; so, assuming that your Cadre Leaders are not at least somewhat power hungry flies in the face of everything we know about sociology and human nature. This means that you must assume that the ruling cadre is motivated by power.
### Even if your Cadres could be peacefully convinced to give up power, other Cadres would just replace them
Furthermore, existing leadership is always keeping some other ambitious group from rising up to power; so, anything you do to dramatically weaken an existing power structure always invites those individuals to rise up and try to seize power for themselves. So even if you COULD get the Cadres to give up power peacefully, there will be some group in your society that will seize that opportunity to try to force their way into their own version of the old system where they will rule instead. So even if you prevent a violent revolution on the front-end, you can expect on on the back-end if you are just stripping them of their power.
### Solution: Give the Leaders More power, not less
This sounds counter intuitive, but the best way to have a bloodless revolution is to give those in power more power than they had before. Your MC has a lot of power that the Cadres want (or fear); so, the best way to make them give up some of the power and privilege that they currently enjoy is to give them some of the power that they already lack.
So, your paramount leader needs to enact a system of shared power in which the elected leaders are given extra rights and privilege's as leaders, but become more beholden to popular opinion. It also must be assumed that the Cadre leaders will by-in-large make up the bulk of elected persons anyway.
So while you can still expect all the candidates to be from these same 7 ruling families, they must now compete with each other for electoral seats, and the only way they can compete is by slowly giving more and more concessions to the voting population which will eventually lead to the voting population becoming among the candidate population... but since no current leaders expect that to happen any time soon, they are happy to settle for a new electoral system as long as it comes with a constitution that guarantees them more power in the here and now.
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Appeal to self interest. This can be either dirty (bribes, threats) or friendly: For example more benefits for their people, enforced cooperation on bigger projects, for example expanded markets and enforced rules on trade between Party Cadres that will increase their market reach.
Relating to the modern USA, the national project to create the Interstate Highway system created whole new kinds of mobility for all States, and has paid for itself 100 times over, including maintenance. It has expanded the footprint of businesses a thousand fold, both for getting supplies and employees, and for shipping their products. It gave rise to great expansion of transportation industries, like trucking and bus service.
Cooperative government does the same, but there must be a central power and arbiter for inter-Group disputes, so the Groups (States, in our case) had to give up some power, agree to follow some standards, etc. But it was in their best self-interest to do this, economically.
So find yourself a great "Big Project" that the Party Cadres do not want to be left out of, because they don't want their people to miss out on the benefits and be left behind. So they will agree to some "fair rules" and a "fair arbiter", giving up power to a central government to enforce rules equally on big Cadres and small and judge them fairly.
That is how the US got the States to agree on a Republic, with a Central Government, A President, A House of Representatives with equal votes, a Supreme Court, etc. That is how Parliaments are formed, a slightly different form of Representative Central Government.
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In the setting I'm making, Orion drives are one of the primary forms of propulsion used in spacecraft. I have been thinking of adding Nuclear Salt Water Rockets (the lithium variety) alongside Orion in order to have a 'classical' rocket punk feel to the setting alongside the raw power of Orion, though why anyone would used a NSWR over Orion is still something I'm figuring out.
So the question is:
**Why would a NSWR be used over Orion?**
-Here are some links for more info for both drives-
Orion:
<https://toughsf.blogspot.com/2021/01/moto-orion-mechanized-nuclear-pulse.html?m=0>
<http://www.projectrho.com/public_html/rocket/enginelist3.php#boomboom>
Nuclear Salt Water:
<http://www.projectrho.com/public_html/rocket/enginelist2.php#nswr>
<https://www.physicsforums.com/threads/clean-lithium-fission-saltwater-rocket.863418/>
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**Scale**
Orion does not scale down very well, the minimum sized start at 10 000 tonnes and much heavier.
Whereas NSWR scales down quite well. The minimum occurs when a critical mass is barely achievable, and that is possible with a mass flow of a few tens of grams per second.
**Maximum Thrust**
(Actually thrust to weight ratio, but allowed by higher maximum thrust)
Also, the potential maximum thrust from an Orion design is quite limited by vibration and thermal limitations. With Orion, more thrust = more heat *in* the vehicle. Plus God's jackhammer beating on your skull at a faster rate might overload the dampening systems.
With NSWR, *all* you need for extra thrust is a faster pump, and a mechanically stronger engine chamber. The heat passed to the vehicle remains constant (although neutron flux may get interesting!). Virtually all of the heat in a NSWR exits with the exhaust, thus not bothering the vehicle itself.
**and the ~~silly~~ real reason**
If you have a whole civilization employing Orion and Nuclear Salt Water Rocket all over the place, then obviously your species is not Human. Or even any form of carbon-water-protein life. Rather they would ***have*** to be some form of radiation-eating BEM.
The environmentalist lobby could be demanding the return of NSWR simply because these newfangled super-efficient Orion drives are simply not seeding enough nutrients into the spacelanes. Why, last quarter's neutron count is below 4e10 per cubic meter already, and there's virtually no sightings of free antimatter being reported at all! We must drastically increase the nutrient release before travelers start starving on the flight to Blito-P3. Never should have scrapped those rest-stops with their fast breeder drive-throughs, I tell you!
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Nowadays we have electric cars, supersonic jets and bullet trains, yet people use their bikes or feet to go places sometimes. Why?
Well, go visiting aunt Penny down the block with a bullet train would be quite wasteful, don't you think? Even the astronauts boarding the Apollo or the Space Shuttle took a bus and walked to reach it.
To be less extreme, for short distance travels the train is often more competitive than the airplane.
Simply said, for some use cases Orion is an overshooting and NSWR is better suited.
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A lithium NSWR *could* have a much higher specific impulse than an Orion drive... if your nuclear engineering was up to the task, you could theoretically get an exhaust of pure fission products, which combined with a suitable magnetic nozzle give you the sort of engine you'll be wanting for going a *really* long way, like to the Oort cloud, or Alpha Centauri or somewhere.
"Classic" Orion drives can't have an exhaust velocity that high because of the need for a whole physics package and propellant disc and so on. You can modify them to make increasingly exotic things like ACMF or z-pinch compression of subcritical assemblies, etc etc, and in the limit you end up with ICF zapping pure fuel pellets in a magnetic nozzle but that's really stretching the definition of Orion a bit.
So, why would a lithium NSWR be used over an Orion? why, when you wanted to fly to Sedna instead of Jupiter.
That doesn't quite gel with your desire for classic atomic rocketry, alas.
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Simple economics. Fissionable materials are scarce, difficult to refine, and thus expensive. Nuclear explosives are wasteful: they literally blow themselves apart before all of the uranium or plutonium can fission, and the remaining fragments (which could be useful in a higher tech) are also widely dispersed. (That is, fallout, though of course it wouldn't fall in space.)
With a reactor, everything is kept neatly in a package. Once your fuel elements are expended, you can pull them out and refine/recycle what's left. If you design your reactor properly, it can even produce more fuel than it started with - see "breeder reactor" for details.
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In my story, my MC ends up hosting a known (and common) alien life form within their head to keep it alive by joining with another sentient being; as a result, both host and alien life form's personality is infused while it's still inside her. This was done on dubious consent due to the death of the original host and the MC being the only compatible host and the alien can't live too long out of a host or stasis.
It is eventually removed but part of it is left behind and (unknowingly) grows into another generation of it's kind but it more parasitic and suppresses more of the host personality than the original alien. This caused the MC to commit a crime on impulse (eg; started a war by blowing up another ship as a preemptive strike). If the MC hadn't had the alien there, the likely chance of committing the crime would have been significantly lower and unlikely to have happened.
The new alien is found and removed fully and the MCs personality is restored to before the first alien was there. This opens them up for an appeal based on the alien's presence and how it affected their behavior, impulse and judgment.
My question is, how accountable would they be for the crimes they committed with the life form involved?
I did try to see which laws could apply but the sci-fi edge makes it hard to find specifics, especially on what sort of sentence they'd receive after too.
[Answer]
In order to be held accountable, all elements of the crime must be satisfied. As you've not defined the crime the character has been accused or convicted of, it's difficult to provide a precise answer, but the principle consideration is 'mens rea', or intent.
The law is quite clear that where a person lacks intent, they cannot be held liable, except for crimes of strict liability. Criminal law has a concept referred to automatism, which is an expression of this idea. A person who is sleepwalking or suffering from a night terror and kills someone cannot be held responsible for the act, since there's no accompanying intent. Similiarly, people have been acquitted on grounds that they were too inebriated or under the influence of drugs to have formed the requisite intent (although this is very rare and difficult to argue; however, the law still recognizes it). Therefore, a person under the influence of an alien could argue a similiar position.
However, there is the second element to consider as well, regarding her own contribution to the circumstances. But for the alien's presence, which she allowed, the event would not have occured. There have been cases in the past where people joined criminal organizations and were prohibited from arguing the defense of duress when forced to commit crimes on behalf of the organisation. This stems from a reasonable policy ground that individuals who willingly join criminal organisations cannot at a later date claim to have been forced to commit crimes under the threat of violence.
In my opinion, your character does not have to worry about this argument, because being a host to an alien is not actually illegal (I'm assuming); joining a criminal organisation *is*, on the other hand. Proceeding on the assumption that bonding with an alien is not illegal, in my opinion she has a perfectly valid ground to argue that she lacked criminal intent, and can therefore not be held responsible for what has occured.
Of course, this is assuming she had no agency whatsoever in commission of offence.
[Answer]
My gut instinct is, legally, while perhaps not identical, it would *closely parallel* an [insanity plea](https://en.m.wikipedia.org/wiki/Insanity_defense).
I'm not a lawyer so I don't know the details of how this would play out, but in the United States there's [a variety of criteria depending on the state](https://criminal.findlaw.com/criminal-procedure/insanity-defense.html).
One common element among states, emphasis mine, is:
>
> In states that allow the insanity defense, defendants must prove to the court that **they didn't understand what they were doing; failed to know right from wrong; acted on an uncontrollable impulse; or some variety of these factors.**
>
>
>
The accused in your scenario seems like they could nicely make use of this type of defense. While they may not have a purely psychiatric condition, they could certainly argue that they still fit the criteria.
There's a number of guidelines and tests as well. From the page above (sorry not posting links to rule details, you can find more info on that page, but I'm typing on my phone and it's a pain):
>
> Depending on the jurisdiction, courts use one or a combination of the following tests for legal insanity:
>
>
> * The "M'Naghten Rule" - Defendant either did not understand what he or she did, or failed to distinguish right from wrong, because of a "disease of mind."
> * The "Irresistible Impulse" Test - As a result of a mental disease, defendant was unable to control his impulses, which led to a criminal act.
> * The "Durham Rule" - Regardless of clinical diagnosis, defendant's "mental defect" resulted in a criminal act.
> * The "Model Penal Code" Test for Legal Insanity - Because of a diagnosed mental defect, defendant either failed to understand the criminality of his acts, or was unable to act within the confines of the law.
>
>
>
If your world's legal system uses some guidelines similar to one or more of the first three there, I could see a defense holding up.
The "Model Penal Code" test, though, may or may not apply.
You could research cases in the past where the insanity defense was used successfully as inspiration.
[Answer]
The answer cannot be black or white.
Several factors have to be taken into account, and it also depends on the legislation.
Factors to be taken into account:
* is the existence of the life form acknowledged by the mass? If in my real world I say that I stole a car because the purple jeejuice living in my garden told me, I would at most declared insane.
* is the influence of the life form established? In other words, was the host aware of the consequences of the hosting? Again in the real world one cannot claim that they didn't know that drinking a whole bottle of vodka would make them drunk.
* was the hosting voluntary or forced? Back to the vodka, if you are pointed a gun at your head to swallow the whole bottle down it might be seen differently than if you drank it out of your will.
And then the legislation: up to few years ago (if not even today, I am no expert in this) in many countries a man killing another man would be judged less severely if the homicide would happen to defend his honor, for example immediately after finding that the other man was having an affair with his wife. Or nowadays in some legislation being under influence when killing a person in car accident is an aggravating circumstance.
Wrapping up, it all depends on the law system you are setting up.
[Answer]
I would consider researching criminal charges where someone has a split personality.
* <https://gould.usc.edu/why/students/orgs/ilj/assets/docs/10-2%20Saks_Article.pdf>
* <https://link.springer.com/article/10.1007/BF02238859>
How does your community view alien/human mind-melds?
Is this like an illicit drug? Your MC should have known better, so is criminally responsible?
Is this like a mental illness? Your MC did not know better, and now receives treatment restoring them to a point of mental competence
Is this like a normal life event? Like getting bad news, emotionally tough, but not an excuse for illegal behavior? Sp MC had a responsibility to control their conduct?
[Answer]
Diminished responsibility is probably the *mitigation* that your MC will use: <https://en.wikipedia.org/wiki/Diminished_responsibility>
The MC will stand trial based on the criminal actions that were committed (blowing up the ship), they may attempt to convince a court that lesser charges apply (e.g. war crime->manslaughter), which the court may or may not accept. If found guilty of any charge, then mitigating/aggravating circumstances of alien possession will be considered in sentencing, which would likely have the effect of reducing the punishment, but there may be unavoidable legal minimums.
Further considerations:
* This type of possession seems common in your world, are there *specific* laws (e.g. possessed in charge of military equipment) that your character may be violating?
* A war has been started, this tends to be taken pretty seriously. It's almost impossible to conceive that there won't be an enormous amount of political interference in this trial. The result will set an enormous legal precedent, be appealed in the highest courts, drag on for years/decades and likely lead to the creation of new laws.
* The crime was also military, it's likely to be tried by a court-martial, which can have very different process and outcome.
On Mental health defences:
* Insanity defence: You MC was of sound mind, but not in control of their actions. A typical result of an insanity defence is being sectioned for mental health, which wouldn't apply here, making it unlikely a court would accept this defence.
* Being unfit to stand trial: MC is now 'cured', this would be pretty difficult to argue.
[Answer]
**THIS IS OF COURSE NOT LEGAL ADVICE I AM NOT A LAWYER I AM JUST A GUY CONSIDERING THIS ON THE INTERNET**
>
> In my story, my MC ends up hosting a known (and common) alien life form within their head to keep it alive by joining with another sentient being; as a result, both host and alien life form's personality is infused while it's still inside her. This was done on dubious consent due to the death of the original host and the MC being the only compatible host and the alien can't live too long out of a host or stasis.
>
>
>
I think the same principle as duress would apply here IF the alien life form themselves was the perpetrator, at least in parallel. If you go and borrow money from someone, only for them to chase after you with a gun demanding their money back and your only reasonable way to get away was to steal someone's motorcycle, whether you could apply a duress defense depends on who that guy you borrowed money from is. If you had a reasonable belief that he was an upstanding guy, then you could apply the duress defense. If you knew he was an SOB, you couldn't claim duress because you should have known what you were getting yourself into.
>
> It is eventually removed but part of it is left behind and (unknowingly) grows into another generation of it's kind but it more parasitic and suppresses more of the host personality than the original alien. This caused the MC to commit a crime on impulse (eg; started a war by blowing up another ship as a preemptive strike). If the MC hadn't had the alien there, the likely chance of committing the crime would have been significantly lower and unlikely to have happened.
>
>
>
This makes it more probable that a duress defense would succeed on paper. If this parasitic personality thing was not known to occur before the MC dealt with it, then her lawyer would be able to cogently argue something duress adjacent (as noted in several previous answers, it would be easy to say that the MC had no *mens rea*, and she couldn't bear responsibility for the situation if there was no reasonable way to foresee the consequences thereof).
However, as pointed out by @David258:
>
> A war has been started, this tends to be taken pretty seriously. It's almost impossible to conceive that there won't be an enormous amount of political interference in this trial. The result will set an enormous legal precedent, be appealed in the highest courts, drag on for years/decades and likely lead to the creation of new laws.
>
>
>
For your story, this generates a *lot* of plot. Anyone who thinks your MC is a threat (like, say, your antagonist, or more insidiously, people whose aims are lined up with hers but who think she's a dangerous element for *starting a war*) or who have something against those aliens and want to create some kind of precedent to make hosting them illegal-- or else under some kind of controlled system-- will have ample reason to try to make the trial about crucifying the MC: the legal precedent would be worth way more than mere gold. Conversely, people who want to help your MC aren't just her friends: the aliens, for one, are going to be VERY invested in making sure any trial goes her way, and even people who may not like the MC personally may try to help her trial because they are incentivized to make sure that the alien hosting is legal.
Basically, because there are lots of cogent legal theories that the MC could cite in her defense, but pretty much all of them are active defenses, and because the actions of the MC are very politically significant, this is going to be a politically dictated trial more than a legally dictated trial unless your judge and jury are very, very impartial. This can be great for your story if you need to generate a major plot point. It can also be terrible for your story if it starts taking away from other major plot points.
[Answer]
I think, at least the way I understand the US legal system, they would be held accountable. If you look at cases of defenses for DID (formerly MPD Multiple Personality Disorder) claiming that an alternate state of consciousness (another "personality") committed a crime doesn't hold up in a court and the person still goes to jail. Especially if the fact remains that the entity in MC's head is still in there in any form at the time of the trail. If it's still in there, it's the responsibility of the body, not necessarily the "personality" in charge, *except* in cases where the person is deemed legally insane for not understanding right from wrong (which others have pointed out). So, I would suggest poking around Dissociative Identity Disorder as a legal defense, maybe there is a case where it was a successful defense I'm not aware of? Could lead you to some interesting places regardless.
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[Question]
[
Are there any medicine out there specifically used to treat serious illnesses (it could be something as simple as painkillers to something for a very rare chronic illness) that could be swapped out for a placebo or a fake alternative at a pharmacy by some kind of gang or cartel for profit on at least a town-level scale without the average, unsuspecting person (or even the pharmacy itself) finding out, at least immediately? (Such as the gang swapping in the placebo (somehow) and then reselling the drug at a drastic markup on the black market)
I was perhaps thinking pain killers, but somehow getting a pharmacy to continuously sell fake pain killers without people starting a riot seemed a tad too unrealistic to me.
The story setting is modern-day USA.
Many thanks!
[Answer]
**Chemotherapy.**
There was a notorious case of a pharmacist who diluted chemotherapy medicines. Chemo does not always work against cancers, and patients do not always get sick (and are happy when they do not!), so this went on for some time. Chemo is expensive and so he made a lot of money this way.
<https://en.wikipedia.org/wiki/Robert_Courtney>
>
> In 1998, Darryl Ashley, an Eli Lilly sales representative noticed
> Courtney was selling three times the amount of the cancer drug Gemzar
> than he'd bought. Lilly initiated an internal investigation but found
> no evidence of illegality and closed the investigation without further
> action.
>
>
> In early 2001, Ashley once again voiced his concerns to a nurse who
> worked for Dr. Verda Hunter (now Hicks), an oncologist in Courtney's
> building, who was also one of Courtney's customers. Hunter noticed
> that many of her patients were only suffering mild side effects, and
> their condition didn't seem to be improving.[4][5] Hunter had
> medication that had been supplied by Courtney tested. That test showed
> that the sample contained less than one-third of the drug prescribed,
> and upon receiving the test results back, Hunter immediately notified
> the FBI.[1][4]
>
>
> Investigators believed that Courtney took a base dose of chemotherapy
> drugs and split it between three prescriptions, then sold them to
> oncologists for the same price as a full dose. He took advantage of
> the fact that oncologists are usually concerned mainly with
> chemotherapy's effects on the body, not the amount of the dose.[4]
>
>
>
There are more recent allegations of this sort of thing in Mexico:
<https://www.bbc.com/news/world-latin-america-38675688> - diluting the chemo or just using some harmless IV solution and saying it is chemotherapy.
Avastin is another cancer fighting drug and there was a recent case of exactly what you describe - organized criminals selling fake Avastin.
<https://www.npr.org/sections/health-shots/2012/02/15/146929475/fda-warns-about-fake-avastin-in-us>
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[Question]
[
In my setting there is a race descended from [Gigantopithecus blacki.](https://en.m.wikipedia.org/wiki/Gigantopithecus)
These creatures retain much of their ancestors physical features, such as:
•An impressive height of 2.75 meters (9 feet in freedom units)
•Disproportionately long arms and plenty of strength to use them (as strong as five men)
•They retain an herbivorous diet that necessitates a lot of eating and a generally reserved energy expenditure until combat starts, at which point they are much more strong and agile than humans
•They have a gular sack like a siamang that lets them be extremely loud.
•Their wrists can rotate much further than a human, which could make for very interesting sword fighting tricks.
The giant tribes have all sworn fealty to human polities in some form or another due to the fact that humans outnumber them hideously and the giants are intelligent enough to understand that they need the assistance of humans to survive. Humans in this setting are at a 14th century European level.
While on its face giant warriors would be good, they have a few serious disadvantages compared to humans.
•As mentioned previously they need to eat a lot of food.
•They absolutely suck at endurance running compared to humans and won’t be able to march as long.
•They are a bigger target for archers and arbaqusiers.
What also needs to be taken into account is their cognition. They are equivalent to humans in their reasoning skills, but they are significantly less ambitious or creative. They learn how to use spears, bows, swords, and even guns with ease as long as they can actually wield them.
So taking into account these giants strengths and weaknesses, what would be the best application for them in a medieval military?
[Answer]
Their lack of endurance may not make them great for extended campaigns but they might be great for Defense!
**Use them to Man the City Walls!**
Imagine being the guy who has to storm the walls. You marched a long way, braved the rains of arrows, dodged the boiling oil, climbed over the bodies of your buddies, and then scaled the wall. You are on of the lucky few who made it to the top of the wall and you are confronted with a 9 foot tall Ape like thing with a shield and a Mace that looks like it was made from the trunk of a friggin' Tree! Your final thought is "well that sucks" as you are launched from the top of the wall with one swing from that mace in an arc that is going to make you land 200 yards away on top of your own baggage train.
IT plays to their strengths. Fighting on top of the wall does not need finesse, but a huge reach advantage coupled with massive strength means a crushing weapon like a mace or large war hammer is going to be hard to defend against. One of these big boys just has to swing it side to side at about human waist height and it won't matter if there is a shield in the way or not. You can't leap over it, you can't duck it, and the impact is going to launch you a pretty good distance. Also, an 80kg human makes an okay projectile against other massed humans and would be pretty darn demoralizing.
If they are at stationary fortifications, the endurance problem does not come into play as much. They will be close to the food supplies.
In addition, they will be really helpful in loading the heavy weapons. The wall mounted catapults, Ballistae, and whatever else that requires a heavy object being flung from the wall. They could even man some of them single handed. A weapon that needs some sort of mechanism for a human to cock could be done by hand. This should greatly increase the rate of fire of those weapons.
[Answer]
**Shock troops**
First rule of war - play to your strengths. Make the most of your assets. What you have here are a group of fighters that excel in close combat because of the disproportionate advantage of superior strength and reach. Using them at range will get you slightly better archers, but that's not great. Not to mention that there lack of stamina means that you want to put them in a job where they don't have to be there for a long time. It's at this point that I'll also say that if you could put them on horses that would be *amazing*, but horses cannot handle nine-feet-tall people in full armor, so that's not an option.
When two armies clash, especially in the dark ages or middle ages, basically there were would form a line of contact between the two armies at the center of the clash. If one side could manage to break their opponent's front lines, the other army's formation would be in disarray, and ripe to get overrun.
So here is what you would do. Take your giants and give them shields - good shields, as in kite shields long enough to protect them. (And, yes, kite shields can form shield walls so long as you know what you're doing.) Hold them back in reserve during the initial clash - no point in them getting targeted. Once the enemy force has clashed with your own, figure out where the enemy is weak, and then send in the giants to crush their front line, being protected by their own shields.
And I mean *crush*. Your giants will not be wielding swords, oh no. Swords are good for stabbing people. But when you have the strength to swing a giant warhammer like a pendulum and gleefully send the enemy soldiers scattering like bowling pins from the blunt-force trauma and watch their morale plummet as it starts raining soldiers on them, then you give your giants a warhammer and let them get cracking. Once they hit the enemy's frontlines and break them, and once morale is destroyed, the enemy's formation will crumble, giving your normal soldiers the means to destroy them
[Answer]
**Corps of Engineers.**
[](https://i.stack.imgur.com/lM3xM.jpg)
[source](https://i.pinimg.com/736x/65/99/3e/65993e4024ca205037c9d787726c265c.jpg)
These big dudes suck at battle. It sounds mean but they will tell you that themselves. They cant figure out what to do and they want to run away when they get hurt. Then when they come back from the forest to eat lunch the little guys are angry and don't want to give them any lunch.
But they are great at building stuff, especially if you have one or two really smart little guys that tell them where stuff should go. They love to dig, and stack up logs, and put rocks on top of each other. The work gets done in no-time. It turns out really cool once it is done!
Also, there
is always a wagon full of food and beer next to the work site.
[Answer]
I would like to use my Ape-Men for:
**Anti-Cavalry units**
During an enemy cavalry charge, my armored Ape-Men secures my frontline, and ravaging enemy's horses with their bare hands, swords or spears.
**Ultra-heavy Cavalry units**
I put my Ape-Men on bulls (yeah bulls, with deadly sharp horns), and make them charge into the enemy forces.
**Fort takedown units**
When my enemy closes their gates, and don't listen to my logic, My Ape-Men climb their walls and open the gates for me.
**Artillery units**
Let's say a normal artillery unit can shoot 2 shells per minute, my Ape-Men unit can fire 4. Plus they can shift/re-align the cannons at astonishing speeds.
**Special Black ops unit**
It seems a little odd to put a 9 feet tall soldier into a covert op in the 14th century, but they do provide extra muscle power.
**And my favorite,**
they are really good at torture and information extraction, due to the game that they play called "tossing the human", which they play until all the limbs of the designated human shatter to pieces.
This being said, carrying extra rations for them is no issue, as if an individual Ape-Man can perform better than 4 humans combined, I am happy to give 4 times the food. 'cuz in my army we are all about quality over quantity.
[Answer]
**Heavy chariots**
I think you'd want to use them similarly to heavy cavalry. Due to their lack of endurance they're unlikely to be much good in extended infantry clashes, so you'll want to hold them in reserve until your main footsoldiers are engaged and then throw them at the flanks to try and cause a rout. The lack of endurance is actually relatively similar to real-world heavy cavalry which become exhausted quickly over multiple charges, and used to change horses to keep up their speed.
You're unlikely to be able to mount them on horses as they're so heavy, but to aid their mobility you could mount them on heavy chariots drawn by a team of horses. They could either fight from these chariots, or operate like dragoons and dismount for combat (leaving their chariots with a human driver). These would also facilitate their withdrawal as they become exhausted, and prevent them from being overwhelmed by the enemy.
**Siege warfare**
As mentioned previously, their skills in climbing would make them excellent during assaults on fortifications. Their size and ferocity would be useful in taking walls and keeps, and by climbing they could attack inner fortifications from novel directions (they wouldn't need to attack towers from the inside upwards as they could climb over the top). I'd expect the design of fortifications to change in response to these threats (smoother walls, more spikes atop fortifications and the like).
**Archers and archery would be problematic**
As you rightly say, you'd want to armour them pretty well against archers. They'd be pretty big targets and slow moving, and would likely fall quite quickly to massed fire. Big shields would be a good choice.
They'd also likely make pretty shoddy archers themselves. Humans have a number of specific evolutionary adaptations that make them good archers. Our disproportionate amount of slow-twitch muscles in our arms is thought to facilitate accurate projectile throwing and fine motor adjustments for things like aim. Also, our brains are really rather good at predicting parabolic arcs for thrown objects. These are all adaptations to suit our pursuit-hunting ranged-combat evolutionary history, and come at the expense of raw strength (this is one of the reasons that chimpanzees are stronger than humans weight-for-weight).
Considering the physical description and herbivorous diet of your mercenaries I would think that they would lack these adaptations, which would make them lousy shots. Due to their size I doubt they'd be swinging through the trees like gibbons, which might be the only way they'd acquire a knack for parabolic arcs and fine motor adjustment. However, this would mean that they would be *even stronger* relative to humans as they could have much more fast-twitch muscle.
Overall, they'd be pretty damn scary if you can deliver them into close combat.
[Answer]
If they retain the climbing abilities for their "apes" namesake, they would be formidable in breaching the defense of castles under siege; only smooth defending walls will be hard for them to climb, they have an explosive capacity of attack once on top, their massive stature will block the defense in narrow spaces (such as the walls top) even if they die there.
[Answer]
This is similar in design to some of the questions about Orcs.
From your description these beings don't use the human muscles designed for endurance and accuracy, but the high-strength muscles most other animals use. This has some consequences for their use.
Armor: On one hand their increased strength would allow them to wear more armor. And having what amounts to living tanks just rolling around the battlefield would be awesome right? Unfortunately the more armor you put on them the faster they tire out, and they already tire out faster than humans. This requires a balancing act between how long you want to use them per engagement and how much punishment you expect them to get. It's likely they'll get lighter armors like leather and gambesons rather than full plate.
Melee weapons: Their lowered accuracy due to their muscle type means that weapons like spears are only useful as long as they form a unit. They are better off with weapons like Halberds, clubs and large swords designed mostly for their bludgeoning capabilities rather than their edge. The prefered weapons would either incapacitate/kill a bunch of enemies in a singles swing or require little effort to attack with again and again. This limits the weapons to spears (with broad heads probably) and clubs. Clubs have the disadvantage that swinging them requires space and opens up large gaps between your creatures.
Ranged weapons: Accuracy might not be that good, but when firing large volleys in a single go these creatures would be devastating to heavily armored opponents. Their strength would allow them to pull back the string of a bow or crossbow with much more force and their ammunition could be a heap of stones or almost spear-like arrows. If they have the agility in their arms they could even use slings. area saturation would be key here to make up for their lack of accuracy. "fight in the shade" style.
So as far as I can tell these wouldn't really be frontline troops. If you do use them for this role they should have to push through immediately and route the enemy before they tire, because the moment they tire they are dead. They are too heavy for horses and could only be carried around by carts if you don't want to tire them. This makes them very inflexible on the battlefield, meaning any formation with these creatures would put them in a position where they don't have to move much and if they fall back their human friendlies will instantly be able to surge forwards and give them the time to catch a breather to either return to the frey or flee.
One of their best uses would be an intermediate artillery platform or as artillery manpower. One or two set the tension on the weapon while it's being loaded so it can be fired quickly. When tired another two take over so the others can rest. Should someone attack the artillery itself it has groups of giant murder-machines who can handle short but brutal engagements. Otherwise they are perfect for slinging overlarge arrows and rocks at much larger ranges than their human counterparts. This keeps them out of the frey and gives them time to rest inbetween the fights. Should someone still attack these archers... Well good luck!
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[Question]
[
I recently came into possession of a rather large mass of molasses due to a misunderstood Alexa inquiry and since the restocking fee is outrageous, I plan on using it to answer a nagging question I've had: is it possible to surf atop a body of molasses?
I've got approximately 1.898 × 10^27 kg of the stuff in a stable orbit around an M class star and I've got the tools necessary to manipulate it around physically, but I don't want to have to be actively stirring it or anything to get this to work, that would seem like cheating. I'm having an atmosphere along with an ozone layer added to it next week since I'm not very good at surfing and wearing much beyond a wet suit would probably make it more challenging than I'm prepared for.
What should I do with this to make it surfable? Like with cresting waves of sufficient height and velocity to propel me and my surfboard across the surface like how surfers do it on water?
If it matters, it's Plantation Blackstrap Molasses, Organic and I've already removed it from the containers it came in (another reason I can't return it).
Ideas for what to do with this afterwards are welcome as well.
[Answer]
Reality Check =
# YES!
As a matter of fact, there was, once in the distant past, a very tiny ocean of molasses here on Earth, and at least one person came pretty close to what we'd call surfing on the big wave.
**Facts:**
It was back in 1919 that an actual tsunami of molasses swept across a rather modest section of Boston Mass on one cool winter's day. A large tank of the stuff exploded, sending almost nine million litres of the stuff flowing through the streets. As with large waves of water, the singularly sweet tsunami carried all manner of debris with with, including broken bits of the metal tank, horses, whole trucks and a large number of people.
[](https://i.stack.imgur.com/xC2wR.jpg)
The tank was 15m tall and 27m wide; the day was cool and the molasses had been warmed to facilitate transfer. Upon bursting, the wave of goo was about 8m high and moving at 55km/h; it shifted several buildings from their foundations, damaged a railway bridge and flooded several blocks to about 1m in depth. ([WP article](https://en.wikipedia.org/wiki/Great_Molasses_Flood))
Of interest one young boy "was picked up by the wave and carried, tumbling on its crest, [almost as though he were surfing](https://www.smithsonianmag.com/history/without-warning-molasses-january-surged-over-boston-180971251/). Then he grounded and the molasses rolled him like a pebble as the wave diminished."
Molasses is rather denser than water (it being essentially sugar), and while the old bromide would have us believe that molasses runs slow in January, history provides the truth of the matter. Warm molasses does indeed flow, and when there is sufficient volume, it [flows rapidly indeed](https://www.chicagotribune.com/nation-world/ct-great-molasses-flood-1919-20161124-story.html).
**Summation:**
It is perfectly possible to surf on molasses. The surfer does, however, need to take precaution as regards molasses temperature & viscosity. If Molassesworld is kept uniformly warm and balmy, surfing conditions should be reasonable, supposing the Bleucheese Moon provides sufficient tidal action.
Once the temperature of the molasses decreases sufficiently, its viscosity rises, creating for the would-be surfer a red-over-red condition: Jamaica Beach closed due to congealed conditions in the Molasses Sea.
[Answer]
This [answer](https://worldbuilding.stackexchange.com/a/159377/30492) states that, once you got a wave, you can surf on molasses.
But can you get a wave?
Best surfing spots on Earth happen where the morphology of the sea bottom is such that if forces the water above to form a large and high wave. The famous spot in Portugal where people bet their life surfing 30 meters high waves is right on a canyon which channels the water. Same for the bowl in the Hawaii.
And here you have the first problem: your planet is made only of molasses. You have no rocky or sandy bottom. With decreasing temperature you have just a more viscous molasses.
And here comes the second problem: you can't have even large open sea waves. As I stated before, at a certain depth the molasses will be too cold to have a decent viscosity. So you have a rather shallow layer of liquid molasses over a thick layer of more viscous molasses. (let's not venture into what happens deeper in the planet). On this shallow layer the winds will have a limited effect, and that effect will be dampened by the viscosity.
[Answer]
## Discard almost all of it
You've got a Jupiter-sized mass of something which is only about 10% more dense than Jupiter, so you're looking at about 2.5g on the surface. That's going to put a damper on wave cresting and ease of surfing. On the other hand, you've got no landmasses to break up winds or currents and the atmospheric pressure at the surface is going to be much higher as well, so the winds and resulting waves will be quite impressive. So you're basically attempting to surf in a major hurricane while weighing 2.5x your Earth-surface weight.
If you drop down to something more like an Earth mass (~5.97x10^24kg), or even Earth-size (resulting in lower surface gravity due to the lower density), you'll have a much easier time of it. Maybe use some of the leftover to put a moon around it and get some tidal action going, but again, the lack of anything resembling a beach or shore means that waves will build up on their own just fine from atmospheric action alone. They just aren't likely to break since there's no shoreline.
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I’m designing a utopia but there’s one problem remaining.
The setting is one of a highly advanced human society. We’ve eliminated disease and allowed the natural environment to replenish. Individuals live for about 100 years on average with good physical ability for almost their whole life. Space travel is possible, and we’ve colonised mars and the moon. Nothing travels faster than light, so we’re restricted to this one solar system and because of the differences in gravity, anyone who visits one of the colonies will only stay for a short time.
The challenge I’m facing in building this world is about human psychology. What should the social system be like to ensure that people are happy?
I was thinking that people need to be challenged and maybe even deprived for the first part of their life to allow them to appreciate this world in their later years. Say that until the age of 20 people have very basic and stressful lives and are told by some figure of authority that they must work hard for the sake of their future. After 20 years, they’re told that they have succeeded. They’re then entitled to go out and have a happy life where they can work if they want to or just enjoy doing whatever they enjoy doing. It’s a lie and no one ever fails. For the rest of their life all individuals have a memory of unpleasant times, which allows them to appreciate pleasant things, and a sense that they have earned the life that they enjoy. The idea is that with those things they will be happy.
I don’t know if that’s the best design for a social system that allows people to be happy. It may be too simplistic… What are some alternatives?
[Answer]
**Happiness is not a destination, it's the way you travel.**
Sure, being challenged and overcome this challenge will bring some happiness, as receiving a paycheck when you need the money for something nice. Still, it'll be fairly short as a state of being, and *status quo* will come back shortly.
You cannot cheat on happiness, it has to come from within, and as such not everybody will be able to reach it.
Ian M. Banks writes very interesting depiction of a futuristic culture (names "the Culture") kinda like yours, by which I mean that they don't need to work, have better bodies than us and near immortality. They can do pretty much whatever they want. Most of them finds a meaning in their live in hobbys or in participating in their society's in a way which they like or think is meaningful. Some of them are restless without knowing why, as if they needed something different to be happy.
Every person is different. You can create a world where everybody has everything to be happy, and there will still be heart breaks. There will still be (some) mortality. People will miss other people who decided they would travel far away.
What you need isn't some clever explanation of how people will achieve happiness. That's not a long term thing. What you need is to find a way which will permit people to stay happy, to find meaning and motivation... and this is something everybody has to find for themselves.
This, or some dystopian mean to make them happy whether they want it or not, like drugs, mind control or invasive surgery. You probably don't want that.
Personally, I very much like the concept of "rite of passage", and if you want to point out a cultural thing which could explain a lot of the happy-oriented mindset of a specific society, a rite of passage could be an important part of the explanation. It's kind of similar to the "they have a struggle they have to overcome" thing you mentioned, but less "we cheat them into thinking they did well so now they are happy" and more "they live through an experience which teach them deep truth about themselves, and with this new knowledge they are better prepared to find what is meaningful and important to them, thus being closer to the path which will bring them happiness".
You can engineer an environment which will help them to be happy. You cannot engineer happiness like you would engineer a one-size-fits-all t-shirt.
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As a whole, there is no societal way to achieve this (many have tried) however as this is Sci-Fi there are a few technologies which could achieve this in part or be used to create a false utopia for conflict in your world.
**AI**
At the less intrusive ends, each person grows up with an AI "Robo-Buddy" that can both function as a personalize therapist, confidant, and / or moral compass. It would be programmed to help with emotionally trying times, lead people to fulfillment, and dissuade humans from harmful behavior to themselves and others.
In a more intrusive fashion, AI begins to replace human constructs and relationships. AI could replace human governments, perfectly dictating policies and justice for the greatest benefit of all. All dangerous or monotonous work could be automatized, leaving only the exciting and challenging stuff. If you even wanted to work at all. Work becomes optional, robots produce enough wealth to provide for all of humanity. Pushed even further, robots begin to replace core human relationships. Parents, co-workers, friends, lovers. All could be replaced with different robots, perfectly tailored not to what you want, but what you need.
**Biochemistry**
Basically, humans begin to build the best societies by first fundamentally changing themselves, be it by genetic engineering, changing chemical balances in the body, or evolution. Everything down this path with be controversial. At the less extreme ends conditions such as sociopathy, narcissism, and depression are 'cured'. Further in, start changing humans emphasizing 'good' traits, such as cooperativeness, empathy, caring and reducing 'bad' traits such as spite, xenophobia, greed, etc. At the extreme end, is of course, happy pills. Take two everyday and your sorrows will go away.
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Much of your analysis is correct, although "deprived" is not a word I'd use.
People are happiest when their actions result in progress--they feel that their lives are under control that way.
When you take that ability to improve away from them people aren't ever really happy. Examples of denying their ability to improve might handing them everything as through inheritance or a purely socialist state or where a high cost of living where average salaries aren't covering basic living costs.
I suppose to make people happier I'd ensure that everyone started out in the same situation (No inheritance, no cash handouts) and I'd minimize required living expenses (Housing, utilities, healthcare, childcare, food, transportation,...) allowing people to actually see the benefit of the money they earn and give them the desire to earn more (knowing that it will benefit them directly and not just go to "Pay Bills")
[Answer]
You can achieve a basic happiness by guaranteeing the following 4 things:
* *Satisfying biological impulses:*
So you would have to create a system where everyone can satisfy their biological impulses (food, comfort, sex, children, etc).
* *Achieving goals*
To get what you want out of life, which will differ from person to person, but all the simple things should be manageable if the government is on your side.
* *Reaching rewards and goals, only after hard work:*
They would all need to work arbitrarily hard for these and their other goals, because otherwise it would not bring the population as much happiness.
How hard your people have to work would have to be established by your government. This amount would have to be standardized or there would be feelings of injustice and [relative poverty](https://en.wikipedia.org/wiki/Poverty#Relative_poverty).
* *Avoiding psychological pain:*
Everyone would have to have some kind of mental health consultant that would shape the population's values, guarantee their self esteem, and sense of purpose, and so on.
*Result:*
And then with all these measures in place you could give everyone a **basic level of happiness**.
See, this is only the beginning because happiness is complex. The need for freedom, artistic expression, creativity will not be accounted for in the stated system. Freedom based happiness is not consistent with any kind of totalitarian order that can guarantee basic happiness. And any system that guarantees higher freedom based happiness cannot guarantee basic happiness. **The two are mutually exclusive.**
[Answer]
The only way to make everybody happy is to fulfill this simple plan:
1. Embed in everyone's heads one simple thought of what happines is (like "you are happy if you have ZPhone")
2. Justify this "happiness" definition (give everybody ZPhone)
It may be religion, material possession, lifetime event (ex., [hajj](https://en.wikipedia.org/wiki/Hajj)) - you name it. See "Equilibrium" film as an example of how it can be achived (far from the best way in my opinion, but still an example).
In all other cases deversity of meanings of hepiness and life situations would lead to majority of people to consider themselfs unhappy (and others to be happy - I do not remember the name of this phycological paradox).
And happines has little to no corellation with wellbeing. Men dying in povetry from painfull cancer can feel happer than young richboy surfing at Hawaies (or it can be the opposite). So total happiness doesn't imply that everybody leaving in a decent and/or equal conditions.
[Answer]
**Gradual access to resources**
One alternative would be turning your initial proposed scheme of things completely around. When you design society that enables happiness for everyone, there must be certain technological and social level that makes it possible. To make young people live Spartan life you need some enforcement and attitudes toward education and upbringing that are not widely available. Member of highly developed society will not be suitable for the role of a hardhanded scoutmaster.
Considering this, I would stay with normal and liberal education without trying to inflict some artificial trauma. At the same time, there will be limitations imposed on young people in terms of access to means of travel, tools, entertainment and life choices. Nothing different as what we are trying to do today, but at the possibilities of post-scarcity society are much greater, the contrast between adult life and the childhood will be much bigger.
We don’t need to confine the young in the military boot camp, instead there will be invisible border between them and adulthood. Teenagers ID chip will prevent them taking off in a shuttle and hitting the moon while high on latest mood-altering chemicals. We are also not making everything available to them when they reach 20, otherwise there will be too many moon craters created during 20th birthday afterparties. There needs to be a system that releases access to high-energy technologies and activities gradually, based on some kind of grades or behavior log.
[Answer]
**People Forget.**
Once your people get to the no-work no-trouble level they will suddenly be very happy but that happiness wouldn't last. After a while (depending on individual when, it may be weeks, months but certainly not years) they forget the experience of troubles and misery almost fully (the part they dont forget is very little and negligible). Note that they do remember the trouble times just not what it *felt* like. Its like when you meet an old friend or visit a house you used to live in after a long while you suddenly remember the experience but before that you have almost fully forgot the experience.
People need to go through misery after a while. Thats a sad truth. Most that you can do is lessen the blow, may be just make them visit poors every month or let them BE poor for ten days every quarter year.
Your technological progress cannot really stop people from hurting each other, if not anything else people can very easily hurt each other emotionally.
Set up some punishments in place for undesirable behavior. Make punishments public - anybody can watch a punishment, just dont force people to watch punishments.
Our bodies and our minds are set to live in our world where misery is rampant, we can handle some, we get bored if we not get some in a while. Unless you are making angels who have perfect bodies and cannot think wrong you do have to put some misery in your world building.
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In a lab at Caltech [Ken Libbrecht](https://www.its.caltech.edu/~atomic/) has been simulating snowflake formation and under absurdly exact laboratory conditions, they have been able to create almost identical snowflakes.
Clearly, in the real world, we do not observe identical snowflakes because each snow flake has different conditions as it falls from the sky to hit the Earth. Humidity, wind, temperature are not uniform enough to produce "identical" snowflakes. The process is too stochastic. Here is a cool infographic portraying all the different possibilities:
[](https://i.stack.imgur.com/QBItV.jpg)
**Note:** To prevent a straw-man stalemate, I do not propose the snowflakes have to be 100% identical down to the very quark or subatomic level -- I'm not taking an absolutist position. I'm just using "identical" in the reasonable sense. Suppose even after studying two snowflakes carefully for a few minutes, you still can't find any differences.
## Question
How can I construct a world such that the humidity, temperature (and other relevant factors that the answerer wants to address) are as uniform as possible?
[Answer]
You cannot: the size of a world is so large that, even with an extremely narrow statistical distribution of physical values, you will end up with noticeable differences, which would not emerge on a lab size environment.
At most you can scale up the lab environment to the size of a small building, but as you get larger than that, statistics will beat you.
[Answer]
I'd like to offer a frame challenge, based in part on your note on straw-man stalemates:
### Snowflakes are already all but identical
Snowflake classification does not have a particularly long history; while the ancients remarked that there were columns and planes, that is about as close a study as anyone was able to make until the [1880s](https://en.wikipedia.org/wiki/Snowflake#Classification).
Now, as it happens, I don't recall ever really seeing columnar snow crystals; I suppose I must have at some point, but all the ones I actually remember are planar. Similarly, I happen to recall that the Ancient Greeks described columnar snow crystals. All of this leads me to believe that for a given climate, you should expect to mostly see one type or the other, or combination ones in transition climates (or at any rate, than any given cloud should give one kind of snowflake or the other).
In any case; to the typical naked-eye observer, snow should be expected to consist of "reasonably" identical particles.
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If the temperature is uniform, snow won't form.
The only way I can imagine there being n ear-identical snowflakes is for there to be some kind of curse on the world, it's a simulation, or there's some funny-business going on with nano-machines.
Maybe with some future-technology it's possible that all of the snowflakes are "made uniform" after their formation. (this sort of reminds me of ["Tree diagram"](https://toarumajutsunoindex.fandom.com/wiki/Tree_Diagram) from raildex.)
[Answer]
Frame-challenge
You are assuming that the relevant variables controlling ice crystallization are thermodynamic variables. While admittedly not an expert in fractals, the relevant variables to control crystal formation are microscopic variables such as the initial rotation, velocity, etc. of the water particles.
For a simple example, look at the [Ising model](https://en.wikipedia.org/wiki/Ising_model). It has far less variables than a Ice Process, but already produces fractal formation highly dependent on environmental noise and initial conditions.
It's pretty messy math that I only have minimal experience with, but fractals are very difficult and certainly not something that can be identically reproduced.
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The mer-folk are typical top-half human, bottom-half fish. They can breath with either lungs or gills. Their homes are *mostly* below water, but some do also extend above. This allows them to do activites only possible above water (such as cook) and some things just because it feels good to "get some fresh air" from time to time and dry out a bit. Strangely human, but don't let them catch you saying that.
Assuming modern levels of technology, and human help if required, what would the mer-society want to use for an above-water floor? Trying to get around without swimming is already a pain, nobody wants to scrape off scales on wet carpet.
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Mid-gloss stone. It would be familiar in texture, resistant to water damage, has an acceptable coefficient of friction both wet and dry, is beautiful and weathers imperceptibly slowly, but naturally, with enough time and exposure to wave action.
It would also visually resonate with other decor elements from their undersea lives, as well as above-water living.
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There are many types of fish and also many ways they propel themselves through the water.
Unfortunately these techniques don't lend themselves readily to walking on water. Various species of amphibious fish have large solved these problems by:
* Wriggling
* Evolving extended gill plates and pushing with fins and tail
* Springing
* Snake-like lateral undulation
If this is an advanced society with arms able to manipulate the environment, one of the necessary requirements may be the need to use your arms in any manner you see fit whilst walking, therefore the most likely form of movement is a Snake-like lateral undulation.
For this undulation to work you need purchase on the floor - it cannot be completely smooth. It is well documented a serpentine motion is useless on smooth surfaces.
Therefore we are looking at a rough material - perhaps a porous limestone, where the motion can be easily attained with reduced effort. Ease of 'walking' would be a desirable trait for any floor.
However, having said that, human society has demonstrated people don't always make a choice solely on 'comfort' or utility, but also on other factors such as maintenance, cost, style and culture. Therefore think of all materials that are rough but with different attributes, depending on their culture or technologically advanced capabilities, such as:
* porous limestone - this may be the most 'culturally accepted' as limestone is common in certain coastal areas
* slate flooring, grouted
* Rough slip-resistant tiles - ceramic or porcelain
* Waterproof easy-to-clean slip resistant sheet vinyl flooring, if they have plenty of oil based product expertise
* Rough etched concrete, troweled or broom finished, if they have access to cement products
* Exposed aggregate concrete, especially if shells and other sea floor materials are used as aggregate, could be a good cultural mix with utility.
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My question here is if there is any circumstance, however unlikely, that could lead to explosive nuclear fission that was not set off by intelligent creatures. I'm working on some bizarre planets for my heroes to find, and I was thinking of one where nuclear explosions are an environmental hazard. Is that possible?
Say you've got a planet with extremely abundant uranium 235 (or whatever other nuclear fuel you require). Like huge boulders of it in ore strains in the ground and rolling around on the surface.
The geology, atmosphere, oceans, volcanic activity, size and structure of this planet are all flexible. The only constraint is that it must have a solid surface (it isn't a gas giant).
Could earthquakes, volcanoes, or meteor strikes set off the naturally abundant nuclear fuel, making subterranean or surface explosions? Any other unlikely but plausible scenarios for 'all-natural' nuclear explosions?
[Answer]
Pretty much no. The reason is that you can't accumulate a critical mass slowly. It must be assembled quickly. How quickly? With pure U 235 (which is easiest, I believe of all isotopes to make go bang) the original Manhattan Project design was to use a big bunch of gunpowder (well, not gunpowder, though it might have worked, but another more convenient chemical explosive) to shoot what amounted to a sub-critical U 235 bullet into a sub-critical U 235 target. (bang) BANG!
This doesn't work with plutonium. If you tried the same thing, you'd get a fizzle because the subcritical chunks are being assembled slowly enough that the two chunks heat up and melt and go Poof! before they impact. (The problem is that when we make P 239 it is invariably contaminated with P 240 which produces enough neutrons spontaneously to set the thing off before it's fully assembled.) See <https://en.wikipedia.org/wiki/Gun-type_fission_weapon> for more.
It turns out that the natural Oklo uranium deposit in Gabon underwent a natural fission process a couple billion years ago. This was *not* a bomb, but it's estimated that it produced 100 kW of heat continuously for a few hundred kYears. See <https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor> for more.
The timescale of natural processes for concentrating uranium is thousands to millions of years. The time scale needed to get a Bang! when the mass goes critical is milliseconds. It's very hard to imagine a plausible scenario which bridges this gap.
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You would need to concentrate a lot of reasonably pure uranium in a very little volume in a very short time, otherwise what you get is either a [fizzle](https://en.wikipedia.org/wiki/Fizzle_(nuclear_explosion)) or a meltdown (most likely) or a [slow, slow cooking like the Oklo reactor](https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor).
Pretty much the only way of obtaining the required condition of *prompt criticality* is smashing together several (at least two) pieces of fissile material to both increase the mass and its density. Temperature changes alone may achieve this (e.g. shifting plutonium from its beta to its alpha phase), but the likeliest result by far is a fizzle. That's one of the reasons why a nuclear weapon requires extreme precision in machining and operation, and *preventing* a nuclear explosion is relatively straightforward, if [dangerous](https://en.wikipedia.org/wiki/The_Long_Watch).
Also, if the uranium is present from planet birth, it will sink to the core of the planet and guarantee it'll remain a molten inferno for a *very* long time. And still no fissionables on the surface.
You need a Heavy Element [Heavy Late Bombardment](https://en.wikipedia.org/wiki/Late_Heavy_Bombardment) :-).
You could have some weird condition that brings about neutron reflecting elements and gets a "natural" [Demon Core flash](https://en.wikipedia.org/wiki/Demon_core#First_incident), but that's really farfetched too.
So, farfetched for farfetched... one even more contrived, but spectacular possibility is this:
* a double star system, with a primary luminous star of about 7 solar masses and a 2.3 SM neutron star.
* the system came about after a complicate merger of two smaller neutron stars
* a planet, possibly once orbiting the primary star, is in orbit around the neutron star (it could orbit the primary too, but the neutron star would need to be farther out).
* the planet has captured an appreciable quantity of the [heavy element accretion plume](https://www.theatlantic.com/science/archive/2017/10/the-making-of-cosmic-bling/543030/) once orbiting the neutron star.
* it turns out that the neutron star magnetosphere is weirder than expected, and occasionally gives rise to [colossal core eruptions](http://www.dailygalaxy.com/my_weblog/2010/08/rare-neutron-star-eruption-offers-clues-to-mystery-of-its-interior-.html). Instead of gamma ray bursts or X-ray showers, this neutron star actually ejects neutron plumes.
* These were rarely detected by Earth astronomers because a free neutron plume [decays before reaching a distance of a few AUs](https://en.wikipedia.org/wiki/Free_neutron_decay), so the resulting gamma signal [would be very low luminosity](https://arxiv.org/abs/1206.0700).
* But now, our planet is occasionally bathed in dense streams of neutrons. They both enrich and transmute surface ores, and occasionally detonate some of them. The effect would be immediate and catastrophic, and quite spectacular; you don't need fissile deposits, more common [fissionable](https://en.wikipedia.org/wiki/Fissile_material#Fissile_vs_fissionable) materials will do.
(One of the reasons this couldn't really work is that at those densities, the "weak" gamma ray burst from neutron decay is sufficient to sterilize the planet twice over. Not to speak of the neutrons themselves, which are no fresh breath of spring. But maybe... an *even weaker* breakout from a rapidly spinning neutron star...)
[Answer]
**Not exactly.**
It won't ever be a boom like our nuclear weapons, more like a massive but relatively much slower release of enormous amount of energy. Even then, it's going to be very rare. It's also much less likely to happen on a planet which is stable enough for people to walk around on. For instance, [one hypothesis](https://arxiv.org/abs/1001.4243) for the formation of the Moon was a natural nuclear 'explosion' that ejected the material for the Moon from a rapidly spinning mass that was the Earth and Moon as one.
Of course, if you've got this much radioactive material on a planet, you're probably not expecting it to be very hospitable.
What needs to happen is for enough uranium to get together and go supercritical.
There are some ways this can occur more easily that needing boulders of uranium rolling around to come in contact and reach critical mass. You can use the presence or absence of [neutron moderator](https://en.wikipedia.org/wiki/Neutron_moderator) or [neutron reflectors](https://en.wikipedia.org/wiki/Neutron_reflector). For instance a large lump of uranium that would otherwise go into meltdown can be moderated by the presence of water. The water not only keeps things cool, it slows down neutrons, keeping them from slamming into the uranium and knocking off more neutrons. Dry out the water and the whole thing melts down. Alternatively you can add a neutron reflector and reflect neutrons back at the uranium to make it go supercritical (this is what happened with the [Demon Core](https://en.wikipedia.org/wiki/Demon_core)).
Of course, you can just cross the line of scientific accuracy and say that these sub-critical lumps of uranium are under immense pressure when the neutron moderator goes away, causing them to build pressure to the point that they explode violently.
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Let's imagine we have few uranium rock with less than critical mass each, but enough mass in total. Put some mineral between them. It is better if this mineral absorb neutrons. Then put this mix under ground at high pressure.
To detonate this 'device' you need to melt said mineral and let surroundings absorb it. Now we have critical mass of uranium under high pressure.
Two problems here: I'm not sure that mineral with such properties exist and not sure that explosion will create enough pressure to overcome pressure of earth crust.
[Answer]
Lets borrow some ideas from Robert L. Forward's *Camelot 30K*. Now, as with most of his aliens I see no way they could evolve, but lets go with something much simpler:
We have a spacegoing plant (It originally evolved in atmosphere and managed to make the transition as it's planet of evolution slowly lost it's atmosphere and then was destroyed by passing within the Roche limit of a gas giant.) It's seeds are incredibly tough, long-lived and radiation resistant. When one comes to rest in a sufficient (which would be quite low) gravity field the plant sprouts. There are plants that throw seeds but this plant took the idea much farther. It sent down a big taproot that is made out of an explosive. At the end of it's life cycle the plant dies, the root dries out and eventually detonates. The seeds are cast a considerable distance this way, sometimes even at escape velocity (the plant normally grows on carbonaceous asteroids.)
At this point a variation arose that used a block of metal in the root to direct the blast better. Denser metals work better, a version evolved that used uranium. At this point it encountered a very young asteroid belt containing uranium that has a far higher percent of U-235 than we have.
It still built the uranium blocks in it's taproot, but now it's actually possible for them to go critical. A critical mass does us no good but as it approaches criticality it gets warm, the root dries and detonates. If the blocks are arranged properly they are blown together and you get a nuclear yield. At first it will be small but it throws the seeds much farther than before (and dispersing it's seed is the big issue for this plant), it's a big reproductive help. Better bombs evolve as well as tougher seeds to survive the launch. Interstellar travel becomes likely rather than requiring quite a fluke.
Now, one of these seeds has fallen on the planet your heroes are exploring. You need fresh uranium and a decent amount of it but you don't need the sort of concentrations that others are talking about which would almost certainly cook your planet.
Now, trapped under an atmosphere the plant can't throw it's seeds offworld but they get dispersed.
Now, this plant was adapted for life in space and conservation is it's driving principle, it's life cycle is going to be slow and it's not going to look like a traditional plant. Your heroes will probably mistake it for a mineral formation until the biologists figure it out--and note that messing with a mature one is asking to get yourself nuked.
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The Humerns are quite an odd species when it comes to mating. They have nine distinct sexes (not genders, they’re biologically distinct) all of which exhibit varying levels of dimorphism and all of which can interbreed with any sex but their own. Don’t even ask about their social structure or mating rituals...
Any given coupling has a distinct set of probabilities associated with it for the sex of the offspring (similar to [these guys](https://en.wikipedia.org/wiki/Tetrahymena)). Some couples cannot have children of a certain sex, others are near guaranteed to have children of a certain sex. The complex social and physiological harmonics this sets up are an evolutionary response to a harsh and ever changing planetary ecology, and ensures that their species can adapt to rapidly changing climates and survival requirements without actually changing too much.
Each pair will have exactly two children, as breeding is done by both parents interlocking and flooding a temporarily shared ‘womb’ with their gametes before separation. The gametes combine, embed in the lining of the parent’s womb, establish a small, simple placenta, mature into a larval/embryonic stage then engage in a frenzied bout of siblicide that ensures only one child is brought to full term per parent.
The question is this:
By what method can many (potentially hundreds) of these embryos be reduced to exactly one while minimising the risk of death of the survivor and also minimising risk to the parent?
[Answer]
Once the embryos are formed, they rely on the energy supply provided by the egg. But that's not enough to make them grow until birth: they need to attach themselves to the womb wall and implant a placenta to start exchanging with the bearing organism.
The womb wall will establish a bond with only one embryo, and this lucky one will be the one capable of providing the strongest hormonal stimulus in a given time frame.
So, dear embryo, if you want to be fed, be sure you are quick to reach the wall, and be sure your hormone shot is the strongest one. Else you are going to starve.
[Answer]
I ... hate to do this. But tiger sharks may point the way here: <https://www.livescience.com/29198-shark-embryos-cannibalize-others.html>
Relevant quotes:
>
> Shark embryos cannibalize their littermates in the womb, with the largest embryo eating all but one of its siblings. [...]
>
>
> That finding suggests the cannibalism seen in these embryos is a competitive strategy by which males try to ensure their paternity. [...]
>
>
> Full-grown sand tiger sharks are approximately 8.2 feet (2.5 meters) long, and mothers typically give birth to two baby sharks, each about 3.3 feet (1 m) long.
>
>
>
So I guess we can do this, it should work ... but ... when Humern science advances enough to figure out what's going on, the Humerns are going to be *absolutely shattered*, emotionally.
Update: Comments asked if they'd really react badly. Some thoughts... I imagine there will be a time when they don't know what's going on (their pre-modern era). Depending on what their society is like before they find out, it may come as a shock. Don't know enough to say if their eventual attitude will be grief ("We are all born murderers, oh the anguish!") or satisfaction ("My sons are **strong**, rawr!"). Pure speculation: eventually they'll put the best possible spin on it, as people are good at finding ways to live with themselves
[Answer]
I would take a parallel with young birds in a nest. Those that develop rapidly due to good placement in the womb, genetic superiority, or predestination grow stronger and more able to defend each other. You might end up with two or more equally strong sibling though, to which you could find an answer in stating that the method of attack could be some acidic secretion or ingestion of their siblings, making each kill strengthen the killer.
If two siblings still remain against all odds, and they are equally matched, some external influence could decide, or you could decide that twins simply are possible, just very rare. Exceptions make the rule. You could also state that it causes complications and either both children die in utero, or their father/mother dies due to *complications at childbirth*.
Note: Before the 1900s, many more women died due to pregnancy, and many more children were stillborn. If your society is not in the industrial age, perhaps a margin of error is even beneficial to both your world and its realism.
[Answer]
At one point within the first couple of (days/weeks/months) each of the larvae will develop a poisonous substance, e.g. enzyme, that will kill each of its siblinngs within seconds but be immune to himself. The one that got randomly
(birds have mechanisms to make this non-random, but it doesn't seem to be the case with your species - or if you would follow the same strategy (eggs laying over a couple of days), you would just waste a lot of good food)
the most nutrition and is just overall the healthiest will develop that ability first and kill off all its siblings within seconds. Theoretically 2 could "mature" at the same time, but the chances of this happening are very, very slim because of the short time to kill off everyone and the long time it takes to mature.
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The embryos might engage in a survival of the fittest/there can be only one type of action, with weaker embryos being absorbed by stronger embryos, providing a significant portion or of the nourishment needed to grow, thus diminishing the burden of this nourishment from the parent.
This would ensure the strongest, fittest possible offspring. Twins would be bad luck, as they would have absorbed only half of the nourishment needed to come out strong and rearing to survive, and would therefore be weak and more likely to die young.
In addition, the parents would bulk up before the mating event, as the production of the many embryos would be very energy and resource intensive on the body. After the mating event, parents would be at near-normal levels of health, meaning that their own ability to survive would not suffer greatly from the need to nourish a growing youngling.
You might want to consider parents' bodies hardening the walls of the womb into an egg and expelling it from their bodies in some way, as being pregnant (bulky, unwieldy and hormonal to name a few issues) would be a serious detriment to survival in a harsh environment.
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One method would be to have a monopolizable, limited supply of something essential to the embryos' survival. For example, a marsupial who produces more offspring than they have nipples in their pouch is dooming some of them to die, because marsupial embryos latch onto a nipple and don't unlatch for several weeks to months (depending on the species). Similarly, if your aliens have one discrete embryo-feeding organ per womb, then only one embryo will have a chance of survival.
Given that your embryos must survive long enough to be able to battle each other (implying the presence of natural weaponry and ability to move), and yet be dependent on a limited feeding supply later in development, I would suggest instead of a placenta, which is designed for ongoing supply by linking to the parent's bloodstream, they start out feeding from a yolk - either individual yolks for each embryo, or more likely a single shared yolk. Once the yolk supply begins to run out, they begin to battle with each other. They may even engage in cannibalism, or if they have a shared yolk their battles may sever some embryos from accessing the yolk, leaving more yolk for the victors. Both strategies will result in a "rich get richer" system where winning battles increases your chance of winning future battles, which is a good way to rapidly winnow down a competitive field.
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The human system generally produces one viable embryo that combines the genomes of both parents exactly as desired. Why not just base it on the human system? Judging by the name you want some similarity, anyway. And you could use literature about humans as a reference, which would be a significant benefit. While the exotic factor would go down, it would also make the humerns more relatable.
So both parents would have wombs and would produce an egg. The periods would be synced via pheromones, so that both "mothers" would have a chance to get pregnant simultaneously. Humans already do this, so details can be copy pasted. Although if having both parents get pregnant at the same time makes sense, it kind of implies that there is a time pressure, so an outright mating season might be better.
Both parents would also produce sperm. This would then be ejected into the womb of the other, or if exotic is desired mixed between both wombs. The eggs in any case would reject sperm of the same sex, so it works the same. It might be nice to give well fed and lonely parents a chance of self-fertilizing. This kind of set up kind of implies that finding mating partners has been a major issue at some point of evolutionary history, so it would make sense.
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In my story all humans except one vanished suddenly. This one received the gift of immortality and is now alone in this world.
Considering that the world is identical to ours. **How much time does this human have to continue using the internet and electronic devices before they stop working?**
If internet is unavailable can the human with enough technical knowledge salvage information directly from server in ISP of Data Warehouses? This could involve hacking and investigating system admins for credential clues.
If energy is unavailable can the human still generate enough energy with a self-built device to work in these computers and servers?
Can the human build new electronic devices and/or automations on his/her own?
The ultimate goal to these questions is to evaluate the possibility to the human to create a sentient android society alone, with only immortality and knowledge supporting him/her.
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In a couple of days or so there will be no internet.
The problem is coal-fired powerplants require human-operated machinery to reload their fuel supplies, the ready supply will be depleted and they will shut down. There's nobody around to manage this in the least destructive way, huge portions of the US will end up without power. When a nuclear plant loses the external power feed it's going to trip--there goes a bunch more of the grid. While there will still be operational generators they will be disconnected from any load--the whole country will be dark.
The internet will survive for a short while longer on backup generators but they'll soon run out of fuel and that's it, the Internet is gone. Your protagonist can't bring it back up.
Your protagonist isn't going to be building any generators, either. However, there is one option that will allow him to get at some of the data: Solar. He can lay out solar panels, hook up an inverter and power any small scale thing he wishes. He can boot any machine he chooses and in general the web servers won't even need passwords (they need a password for admin access, not to view the data) but he won't get to too many of them before they're destroyed by the elements.
He's going to lead an incredibly boring life.
Regarding the long discussion in the comments: Erik nailed what I failed to spell out--while the protagonist can fix any given small piece of the system there's no way he can get anything big up and running because it's going to fall apart faster than he can put it back together.
I realize the grid goes down in a cascade failure. The reason I gave a couple of days rather than just hours is backup generators. The internet will survive the grid crash, it will only die as the generators run out of fuel.
And another thought on the situation: Probably the only interesting path for the protagonist is to uplift some species of monkey so he has other intelligences around to interact with. His toolbox is obviously very limited but he can do it by rewarding intelligence and culling stupidity.
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So the last human would need to choose two places: one would be the lab with the most advanced research regarding the AI and the second one would be a lab with most self sufficient energy sources. Like own power generators, solar powered (or wind, generally Renewable energy sources) or maintenance-free nuclear plant.
Then he could transfer servers, computers and equipment from one to another.
The internet would not be needed as laboratories usually store all data on site (with technology that can preserve the info without power) so he could use internet for 10 minutes to locate the two before mentioned places.
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As indicated by others you will have a varying amount of time. The largest danger will be from nuclear power stations, if people leave without notice and they cannot proceed to a stable unattended long term shut down (cf. Chernobyl and Fukushima) with no outside grid feed.
Some generation sites will fail in minutes, many in hours, most in days and various low maintenance devices in months. The Russian thermoelectric power generators (for remote radar sites) will generate limited power for hundreds of years but are not really portable. Nuclear submarines and aircraft carriers are slightly portable but will require crews to remain on-line an will have similar safety issues to other nuclear plants.
While the internet will outlast the utility grid by hours or days most data centers may not last quite as long. The are an increasing number of (like FaceBook) data centres being built that are carbon neutral, some also energy neutral. Finding one of these that is still running and has local 24 battery storage would be the best as it could run off grid. Using physical access to gain root privileges might be handy. Archive.org is creating a clone of the Internet WayBack machine in Canada (before Trump was an issue) that should have a lot of data available (the primary I understand is in America).
Most utility power stations will need some human or remote hand holding but wind, solar and hydro may be close to monitoring only, getting on-site access should allow for restart if they have failed safe. If they were grid connected it should be possible to feed the grid again but connecting intermediate switchgear manually after a total power loss may be a long process if you have to cross many substations. Just permanently connecting bus bars will be possible as you plan to only have one or two consumers and safety is less important. The control gear these days is networked and remote controlled with GPS synchronised time references on the PLCs. Hydro power may need some spillway control to prevent a dam overflowing and gate control to prevent turbine runaway. Solar will need occasional cleaning of the collectors and wind may self destruct if they do not feather in storm winds automatically under local control.
As mentioned, university labs would be the best bet for research on androids.
Going to get lonely.
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**Not long at all**
**The Internet is kept up only with an army of support engineers**
The earlier answer about the power grid is correct, as well as the implication that one person simply cannot maintain enough equipment to keep things running.
But there's a detail that I happen to know because I work server-side in a web company, which I haven't seen anyone else mention.
No major website runs without constant human intervention. Behind the scenes, of course, all of these 'websites' actually run on banks of servers. These servers are **far** more finicky than most people would imagine. Machines have a hardware failure, and need replacement with new machines. Connectivity brown-outs require manual intervention to fix. The database machine's hard disk gets too full, causing performance to grind to a halt.
Every one of these companies has an operations group: a whole team of people whose job it is to write tools to let them monitor the health of the system, and to address the constant litany of issues that threaten system stability.
It is true that much of the chaos is due to changes on the backend causing problems. But not nearly all of it. The computer software running all these websites is, simply put, too complicated to run 100% unattended.
**Getting a website back up would require significant reverse engineering**
This is also why your main character would have difficulty ever getting any of these systems back online. The average website's back end consists of a complex architecture: something like a dozen different components that all depend on each other. To get the site back online would require understanding that infrastructure well enough to know how to restart everything yourself.
To gain this knowledge, MC would have to find the company's offices (no small feat without internet), find the servers running their internal wikis, their bug report database servers, etc. Then get them back up and running. Then MC has to find their source code. If it's stored on GitHub, well, that's that. You want to find a local copy sitting somewhere on a developer's laptop. Which MC now needs to break into, since they're all encrypted nowadays (because too many employees had lost or stolen laptops full of detailed personal info of too many companies' customers, totally unencrypted so anyone could read it). You can't even read the files without the password or a really clever hack.
Sure, hackers trying to crack DRM don't need any of that. But they're just trying to get one program to work. They don't have to get a whole suite of programs to all talk to each other in a highly complex dance.
Then, if MC wants all the old data to be accessible, MC now needs to find the actual data center where the data is stored. This could be very close to the dev's offices, but is more likely to be very far away. Assuming MC can even find out the location from the data available in the company offices.
Even for someone who knew exactly what they were doing, and had, like, a local copy of Stack Overflow and other online references saved locally (we don't memorize that stuff anymore; Google is usually faster than looking it up in a book), and who knew how to bypass login screens to get the info they need, this would still take months, likely years.
Then, once MC's got this one service back up, it won't stay up unless they're constantly keeping it happy (see point #1). Trying to keep services up that operate out of two data centers that aren't close together will be literally impossible.
And the inevitable fire, earthquake, flood, etc. will permanently destroy the service after a few decades anyway. Normally websites keep multiple redundant copies of production system data, but that won't be an option for our MC.
If MC made it their mission in life, and they were, pre-event, an honest-to-goodness ~~expert~~ genius programmer/hacker , *and* at rigging up small-scale power generators, they **might** be able to find useful services, and get versions of them that run on very small networks MC maintains personally. Each service would take years to develop, so there wouldn't be much time to salvage more than one or two. But that is not "the Internet" anymore, that's just a small local network.
**Making new electronics is highly dubious**
I'm a programmer, not a hardware guy. So I'll leave it at this: I find it very very likely similar limitations will make it essentially impossible for MC to make new hardware. MC might be able to cobble together working units out of recycled parts, but building new parts is probably impossible. Making integrated circuits requires clean rooms that can't even have a speck of dust get inside (because the little wires that make the circuits are much smaller now than your average speck of dust).
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The normal condition of life in a planet (Earth right now) is that below us is the planet's core, and above us is the sky.
[](https://i.stack.imgur.com/dHftl.png)
Now if there's a hollow planet like above, is that possible? How does gravity work on a planet like that?
Since the planet is not fully closed shell, I don't really bother about light from its star, but there's a bonus if the answer include that.
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In general, the problem with hollow-Earth setups is that objects in [hydrostatic equilibrium](https://en.wikipedia.org/wiki/Hydrostatic_equilibrium) cannot be hollow - and planets must be in hydrostatic equilibrium. Planets form through collisions of smaller pieces of rock and dust, and eventually accrete enough matter to become substantially large. There is absolutely no way for a planet to form with a hollow interior; it should have been compacted during its formation.
In a typical hollow world that is fully enclosed, there should be virtually no net gravitational force on a person inside. For a spherical mass distribution, the [shell theorem](https://en.wikipedia.org/wiki/Shell_theorem) states that anyone inside a spherically symmetric shell should feel no net gravitational force from the shell. There will, of course, be variations in mass density, but they wouldn't add up to anything substantial.
A semi-open shell means that the shell theorem is not fully valid, but it does seem to imply that there will be very little gravity. Your image shows the planet about two-thirds enclosed, meaning that most of the field will be canceled out. Certainly all vertical component will be, assuming the two shells are identical.
Additionally, having the shell only partially enclosed means that the atmosphere has a chance of escaping to the outside of the planet through diffusion, where it will indeed feel a net force - centered on the center of mass of the planet, which is probably the center of the shell. There would still be some left inside, I would assume, but much could escape to the outside. I don't know how significant this could be, though.
[Jason K suggested using rotation](https://worldbuilding.stackexchange.com/questions/63178/gravity-on-a-hollow-non-enclosed-world/63180#comment180671_63180) to keep things on the inside surface of the planet inside, via the fictitious [centrifugal force](https://en.wikipedia.org/wiki/Centrifugal_force). Here, the magnitude of the centrifugal force is the same as that of the centripetal force at the equator - the place where it is strongest - is
$$|\mathbf{F}|=F=m\omega^2R$$
where $m$ is the mass of an object, $\omega$ is the angular speed of the planet, and $R$ is the radius of the inside of the shell. The magnitude of the angular acceleration is then
$$|\mathbf{a}|=a=\omega^2R$$
Assuming that the planet rotates at the same speed as Earth, and its inner surface has the same radius as the Earth, then
$$|\mathbf{a}|=\left(7.29\times10^{-5}\text{ rad s}^{-1}\right)^2\left(6,370,000\text{ m}\right)=3.39\times10^{-2}\text{ m/s}^2$$
That's at the equator, where the force is at its greatest.
The planet would need to spin about 17 times as fast or have a radius 289 times as large in order to have $|\mathbf{a}|=g$. It could spin at about 10 times Earth's speed and generate Martian-level surface gravity, though, which would be decently suitable for humans. Apparently, [the fastest spinning exoplanet known, $\beta$ Pictoris b, spins at roughly three times Earth's speed](https://en.wikipedia.org/wiki/Beta_Pictoris_b).1 That means that to generate Martian gravity, the planet would have to have a radius about 11 to 12 times that of Earth - making it the size of Jupiter! For what it's worth, measurements place $\beta Pictoris b at $\sim1.46$ Jupiter radii. No terrestrial planets will get anywhere near that large.
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1 That said, we haven't measured the rotation periods of many exoplanets.
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## While it is unlikely to occur naturally...
A hollow sphere structure is still possible, theoretically.
If the shell of the world is thick enough and strong enough, then it could withstand the stresses of rotation, and possibly gravitational stresses of surrounding celestial objects. This is also the same basic structure of a Dyson Sphere.
Gravity is produced by mass, it doesn't matter what shape it is in. Therefore, a solid sphere of sufficient mass will produce gravity from the center. A giant planet sized pyramid of mass would produce gravity from the center, which would be feel stronger on the planes (closer to the center) and weaker on or near the points. A giant cube of mass would have a similar effect. Things get a bit strange with a hollow object.
A hollow sphere will produce gravity not from the center of the sphere, but from the center of the existing mass, which in this case is material making up the shell of our hollow sphere. For the sake of theory, let's say our hollow shell-sphere is the size of Jupiter, with no mass at all in the center. The thickness of the sphere let's set at the same as the diameter of the earth. If gravity has the same effects, then what would happen is that the middle part of the shell would melt, and eventually compress to metal as the heavier elements precipitate or percolate out of the molten material.
Note that this would happen everywhere throughout the shell-sphere. The theoretical end result would be a shell which is comprised of an inner layer of rock, under which is a layer of mantle, under which is a layer of liquid rock, and finally a "core" of metal, only this would actually be a sheet of metal. On the other side of the sheet of metal would be another set of layers, liquid rock, mantle, and then outer surface of rock.
This would then produce 1g across the entirety of both inside and outside surfaces of the sphere (assuming, of course, that this structure was actually somehow strong enough to retain its shape). However a sphere like this is most likely to be a complete sphere, with only small openings, unlike your picture.
## Your picture will not likely work, based on science...
Gravity on the object in your picture would draw towards the greatest density of mass, in other words, the top and the bottom. This would mean you could stand on the outside or inside of the top or bottom half, as well as stand on the outside or inside of either sphere. Gravity would be less towards the edges, as the amount of mass is also less.
Unless there are external or additional forces not depicted, there is nothing stopping the two halves from exerting gravitational attraction and collapsing into each other. Not to mention the seemingly free-floating islands near the edges of the top and bottom.
## But, since you didn't use any "science" tags... it could actually work.
However, as you did not use any of the Science tags, you could postulate magic, handwavium science, other unknown elements, forces, or environments which would in fact support and preserve such a structure as depicted.
## A bright idea...
Such a world would be placed under extreme gravitational stress if it were to exist in a solar system by the sun and other planets (unless again, you opt for magic or handwavium). Should it exist in a traditional solar system, then the light of the sun will only reach certain parts of the world, casting much of it into shadow most of the time. While that could be thematically and plot-wise an interesting aspect, it would certainly limit what kinds of life (flora and fauna) could successfully exist and adapt.
If the central pillar-like mountain structure was composed of or covered in a highly reflective material, that would alleviate some of the lighting issue, but would also make day/night cycles rather complicated. Also, note that if the orbital path was oriented so that the open middle part was in the plane of the elliptic - with no axial tilt, then there would not be night in many places of the world, only periods of direct light, and indirect light.
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**Reality Check**
Before I start anything, that planet in the picture will not work, period. But... There is a way for a planet like that to be made.
Magnets. You know how magnets work, right? North end comes to south end, but north+north or south+south won't work. Well, that's how this planet will work. Extremely powerful magnets. You would have a mainly north (or south) magnet sphere in the center of your planet, while the inside shell (crust) would be north also (or south).
**Gravity**
Gravity, might be tough. In fact, gravity won't exist unless you have the planet spinning VERY fast, so stuff is pushed down to the "ground," or you could have your planet in the middle of tons of starts in a very rare (most likely impossible) orbit so that gravity from starts will push your animals towards the ground. Or, you can have that your creatures on the planet would have south magnets in there feet, and north magnets in their heads.
Now, here's the thing, this planet will not be able to
1. Have open air to space,
2. Form naturally.
Lets go on 1. the air and oxygen and all that stuff will be sucked out, maybe not sucked out like you see in space movies, but, if this planet just goes and appears. Then yes, like the movies.
and 2. This planet will not form naturally, because the chances are SMALL. its probs in the range of googleplexionths.
But, its your world, so make it anyway you want.
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Gravity is based on mass. it does not matter if a planet is hollow not, it still has mass. The hollow sphere makes the math harder, the concept is the same. It doesn't matter one bit if the planet is enclosed or not. If the hollow sphere below you has the same mass as the Earth, you would experience gravity if normal force.
One wrinkle, however, is that you would now have a thin shell instead of a solid sphere, and this could create unusual gravitational gradients of the sort what would keep Larry Niven up at night...
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Taking for granted that the inhabitants of this world have reached an extremely advanced stage of technological progress, knowing that the only limit to their technology is that they can't violate or circumvent lightspeed, so no space colonization, they could try a most massive work of planet engineering, using the planet itself as construction material to progressively hollow it out for them to make a working ecoystem inside it, taking warmth and heat from the core. Their world would make for the nucleus of a titanic nuclear reactor/sun.
The picture you provided should be shown sideways, so that, as the world keeps spinning, it provides artificial gravity. All other resources, water and food, would come from the surface -at this point, given that these people basically restructured their planet, covering the surface with greenhouses would be the least of their problems.
Titanic compressors could provide fresh air from the outside while inside the CO2 is worked by genetically modified vegetation.
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Gravity graduates to zero both toward the mid point through the outer shell, and on the inside surface towards the center point. You could actually fly around in the middle, but you might wind up like Icarus.
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As already hinted by other answer, it is almost impossible for a "natural" planet to result as you asked.
My idea: a planet-sized generational ship, carrying milions of people toward another galaxy (or a very far star in this galaxy).
After some kind of disaster (or for a specific choice of the builders of the ship), the people inside lost consciousness of living inside a starship, and formed a primitive society. Luckily the machinery that moves the ship is completely automated and self-repairing (or could be operated by a group of technicians who are not allowed to have contacts with the people living in the sphere).
People would then live in a giant spheric biosphere on the tip of the ship and since this ship is in perpetual acceleration, it would create a gravity going from the ceiling of the sphere toward the bottom (similar to your drawing).
Some drawbacks of this idea:
\* a ship with a spheric biosphere on its tip is not very efficient as calpestable surface/volume ratio. Such a design would be better with a cylindric-shaped biosphere.
\* if in perpetual acceleration, this ship would likely travel almost all the time at almost light-speed, which poses a temporal problem. Even if reaching another galaxy would require milions of Earth years, at relativistic speed the time inside the starship would be slowed to the magnitude order of some tens-hundreds years. If your world needs ancient myths (or enough time for people to forget they are in a starship), the travel could be too short
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I can think of at least 2 movies that had aliens invading Earth for water.
Is this a feasible motivation? I was thinking that
1. Water is H20, i.e. dihydrogen monoxide
2. The vast majority of the universe is made of hydrogen
3. Oxygen is also pretty common as it's the 3rd most common element in the unverise
4. We can combine the raw elements into water, so certainly an alien species so advanced as to be capable of interstellar travel to Earth could also easily combine these 2 abundantly available elements into water
But OTOH I'm not an expert and large teams of people working on big budget Hollywood films seem to think it's a reasonable motivation.
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Any alien species which can travel through space will be passing far more water on the way to Earth than actually exists on the planet. The Oort cloud is a mass of comets estimated to be trillions in number and massing at least 5× Earth masses.
Coming closer they then pass the [Hills cloud](https://en.wikipedia.org/wiki/Hills_cloud), which may be 5× greater in mass than the Oort cloud, the "Scattered disk" and the Kuiper belt.
[](https://i.stack.imgur.com/R3iUx.jpg)
*Oort Cloud*
So they pass through up to a light year worth of water frozen into cometary cores before they even reach the outer edge of the Solar System. Once they get into the Solar System, they pass the various gas giant planets, where the moons are largely masses of ice and liquid water. Europa alone has 3× the water of all the oceans of Earth.
Finally, if they do actually come to Earth to get water, they will be dragging the water out of a deep gravity well, adding a large extra energy cost to every gram of water they take. Frankly, this is going about things the hard way, and smart aliens who were after water could be mining the Oort cloud right now at a negligible energy cost and we wouldn't even know it.
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Not remotely. The rings of Saturn contain 26 million times more water (ice) than has ever flowed on Earth.
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The primary reason that Hawaii was annexed as a territory of America is that they believed (and rightfully so) that if they didn't annex it, some other nation would, but which nation? There are a variety of possibilities, from the ever expanding English Crown, to the Japanese empire. If for some reason, America was unable to annex Hawaii, what nation (if any) would most likely annex it?
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Japan.
When I was on vacation I bought a little book on the [history](https://en.wikipedia.org/wiki/History_of_Hawaii) of the islands. The economics and population make this answer obvious. The population was evenly split at 1/3 from the US (caucasian), 1/3 Japanese, and 1/3 Polynesian. The economy was based on US and Japanese interests. Why ever would England get involved?
I don't believe your opening sentence, either. Businessmen influenced the politics and US had close economic ties for some time; only reason it wasn’t annexed earlier was prejudice over not having a white majority population.
The US had a military base there since **1887**. It became a territory in 1898.
If another country were to become tied, it would have to be before this time. Read the Wikipedia article and consider what would happen if the US was not expansionist or didn’t have the resources at the moment or other political issues got in the way: if the business interests wanted to stabilize the government (read: overthrow the monarchy) with help from gunboats, if the US was not supplying one then Japan would be the next choice.
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1. France
2. New Zealand (then part of the British Empire) => they already left Hawaii, so obviously didn't annex it
3. Independent
If I look a the other islands in the Pacific, all of them either seem to belong to France, to New Zealand, or to be independent (i.e. Micronesia). Japan does not seem to have any far out islands in the Pacific.
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Since no one else has mentioned it (and to add some variety), what about Germany? Or more realistically, a [German version](https://en.wikipedia.org/wiki/German_colonial_empire#Company_land_acquisitions_and_stewardship) of the East India Company seeking to "stabilize" the area in exactly the same manner as the U.S. did. A German "entrepreneur" just does it first. I'm not saying this is the *most* probable, just putting it out there as a possibility.
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England was not expanding her interests in the Pacific at that time, Japan is the obvious choice — but they were not really active in grabbing overseas territory until about 1894 when they started grabbing bits of China — if the US had held off until the early 1900s they would have faced a challenge from Japan I think.
Interestingly Japan was a key British ally in WW1 and Britain may have had a tough time choosing between supporting Japan and Supporting the USA if there had been an issue over Hawaii in 1914.
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At least in part, I think your reason why the US can't/won't annex Hawaii will play a role in this. Prior to the Spanish-American war (1898), Spain had possession of Guam and the Philippines. If your alternate history precludes the US as a military power, they may have kept them, or even expanded to rule other islands as well.
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Would a large, I mean large, impact crater on a spherical world be noticeably distorted on maps using different projections? Eg mercator, hanmer-aitoff, equidistant Etc.
Side question - Would there be a difference if it was a head-on circular crater or a side-on deeper on one end crater?
I assume if there was distortion, it would depend on the latitude? Further north/south resulting in more skewed depictions? Is there a handy calculation I can do to figure out what this distortion is, so I can draw the crater correctly using different projections.
My scenario has a large (haven't actually measured it yet) crater between the tropics and about about 50 degrees south. Rough guesstimate using 69miles to a degree latitude equals about 1380 to 2070miles wide. Let's make it nice and easy and say, 1500mile wide crater.
I'm trying to figure out how to draw my map compared to what you would see from space...how I wish I could just have a 3D model!
Which projection would result in a depiction of a recognisably circle crater with little to no distortion?
**Edit**: This question is not (and answers should not be) opinion based, but rather an answer that provides the least visual distortion. For the close and down voters, I have removed the request for the 'best' which would be opinion based, and clarified it to simply the one that would result in the least distortion. No matter how much you prefer a particular projection, distortion is pretty hard to put down as opinion. It is either distorted or not! FYI, I can't see close votes on my phone, so some comments next time would be very helpful! oops, triple checked. Apologies. I can see close votes on my phone, but no notifications pop up so it isn't drawn to my attention at the time. Please, still leave some comments so that I can get a heads-up.
I have accepted an answer for the extreme helpfulness of it but feel free to answer still if a better projection is out there! **Thank you** to Durakken for the very helpful [Link](http://maptoglobe.bitbucket.org/) that has helped me enormously to visualise my test map as a sphere. I now just have to scale down the landmass and play around with the different projections (I may have had the measurements wrong for my crater size!) [](https://i.stack.imgur.com/cDaxY.jpg)
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Here is a equirectangular projection of how the hit would look. red lines are 0 and 45 degrees, black line is 50 degrees. The circle is the rough size of your crator on an earth map.
[](https://i.stack.imgur.com/k4wIA.png)
You can DL this and see how it projects on a 3d globe as well as a number of other projections [Here](http://maptoglobe.bitbucket.org/)
Basically, all you have to do this is draw a circle and squash 60-70% on the north and south side. I could have made it perfect by getting the exact number from wiki, but I just thought of that this instant and don't feel like editing so... blah
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Quoting [Wikipedia](https://en.wikipedia.org/wiki/Stereographic_projection#Cartography):
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> The [stereographic](https://en.wikipedia.org/wiki/Stereographic_projection) is the only [projection](https://en.wikipedia.org/wiki/Map_projection) that maps all [circles of a sphere](https://en.wikipedia.org/wiki/Circle_of_a_sphere) to circles.
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(Some links added by me.) So if you want to make sure that your crater appears circular no matter where on the planet it is, then I'd go for this projection. You can project half the planet's suface reasonably well (albeit already with considerable length distortion), but you'd need the whole infinite plane to show the whole planet which is obviously not feasible.
If you can choose the projection after you know the crater, you can choose [an azimuthal projection](https://en.wikipedia.org/wiki/Map_projection#Azimuthal_.28projections_onto_a_plane.29) with the center of projection (which need not be the center of the map) incident with the center of the crater. Due to the radial symmetry of an azimuthal projection this ensures that the crater will be represented as a circle.
Of course, most azimutal projections tend to have their center located at a pole, or perhaps at the equator. So using such a map on earth (for one of the “tiny” craters we have) would likely be perceived as strange, and putting undue emphasis on such a feature. But if your crater is as pronounced as the size suggests, then it might well be “the obvious thing” for any civilization to use this prominent feature of their planet as the center for all world maps.
All of this is assuming a circular crater, as from a head-on impact. If the crater is not circular, then these projections would represent that fact by not creating a circular image of it. Since I don't recall seeing any pictures of non-circular craters on the moon or similar, I'm not sure this can actually happen. Perhaps the main force behind the formation of the crater is the shockwave which radiates out from the point of impact, and the horizontal velocity of the object has negligible effect on this? Perhaps should ask on [Physics SE](https://physics.stackexchange.com/)…
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I've actually created a simple interactive plot of how circles appear in a Mercator projection:
<https://www.desmos.com/calculator/0k3bojxx6k>
You can vary the two sliders. R is the radius of the circle (expressed in degrees, 90 corresponds to a circle that covers half of the sphere) and φ is the latitude of the center of the circle. I've set the parameters roughly equal to what your crater would look like if the planet is similar in size to earth.
Here's a quick image of what that looks like:
[](https://i.stack.imgur.com/JaDUE.png)
The orange curves show an orthographic projection of the sphere and the circle (what the planet would look like from really far away). The red curves show the Mercator projection.
So at the proposed size, Mercator leaves the crater looking mostly circular, but it will distort the position of the center of the crater.
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I've already had this problem. To solve it, I drew a circle on a globe (an old globe, may I add, which I reused before chucking it for good, and I used a pin, a string and a thin-tipped felt pen to produce the circle) with lines for latitude and longitude, then I got a mercator map with only longitude and latitude lines and drew a point at each one of those lines. Then I drew a line connecting all the dots.
To be fair, I wanted an extremely large crater (hundreds of km) and, for the end result, I needed the margins of the crater to have eroded quite a bit, which meant the lines connecting the dots could zig-zag some (not to mention I further distorted the resulting crater edge later on).
Nevertheless, the end result can be applied as a mask on Google Earth and looks rather round, while it looks plain funny on the mercator map.
EDIT
There's another way, which should be easy with the latitudes, but not so much with longitudes. This will only work well for large craters... like your own.
First, find out how many miles wide you want your crater to be and draw a circle on a milimeter paper (or a very finely scaled layer on GIMP/Photoshop/etc) where you can have an easy scale. Now you know that 1500 miles equals 150in and you can easily add a layer for latitude where you draw a line every 69 miles. Then you decide which one is for the Equator and number them all accordingly.
Next, find out how many miles the crater spans at each latitude. Now add another layer with lines for latitude and longitude.
Next you need to go to a site like <http://www.nhc.noaa.gov/gccalc.shtml> and find out how many miles span a 1º longitude at each 1º latitude your crater spans. So, at 0 latitude, each 1º longitude encompasses 69 miles too; but at 50 S latitude, 1º longitude encompasses 44 miles.
So, if at latitude 46 S your crater spans, say 56 miles (while 1º longitude spans 48 miles) you know you must plot the edges of the crater a bit wider than a 1º longitude.
Or you can do this only for the radius, rather than the diameter, and then just copy onto a new layer, flip and voila.
It will be more accurate than my first suggestion, and a whole lot more labour intensive, but it should work.
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If you're concerned about distortion, you could always use a [Dymaxion map](http://bfi-internal.org/2013_Map_Contest/final_lrg/005.png). It'll keep you from having any distortion, though placement of the crater might get tricky at that size if you want it all on the same map segment.
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Three map projections provide good, minimally distorted maps of areas similar in size and shape to North America. Each of these projections can be optimized for the latitudes you are mapping:
* The [Albers Equal-Area Conic Projection](http://mathworld.wolfram.com/AlbersEqual-AreaConicProjection.html)
* The [Lambert Azimuthal Equal-Area Projection](http://mathworld.wolfram.com/LambertAzimuthalEqual-AreaProjection.html)
* The [Lambert Conformal Conic Projection](http://mathworld.wolfram.com/LambertConformalConicProjection.html)
The USGS has a [graphical comparison](http://egsc.usgs.gov/isb//pubs/MapProjections/projections.html) of how some of the most common map projections are projected, and how they make North America look.
J.P. Snyder of the USGS wrote an excellent book titled [*Map Projections -- A Working Manual*](http://rads.stackoverflow.com/amzn/click/9998605067). It explains (and proves mathematically) the properties of the common map projections. It discusses how the projections are related, how to measure distortion, and how to optimize the projections to minimize distortion.
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**Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers.
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This question does not appear to be about **worldbuilding**, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help).
Closed 7 years ago.
[Improve this question](/posts/52093/edit)
At first, I know that the evolution never stops and that humans are still evolving of course.
But I recently wondered if the evolutionary mechanism are still fully applicable to the human society. Since we have reached a technological level where practically everyone can reproduce and survive, the so called survival of the fittest or better the survival of the best adapted is not a significant driving force anymore. Of course mutations are still occurring and one lives longer than the other. But basically everyone can pass its genes to the next generation and not just the "best" ones. Then I read about the Flynn Effect that states that the IQ is increasing from one generation to the next. This is not too surprising since our today's brain needs to process much more information than the yesterday's brain. Is this effect explainable with evolution? Is it the evolution of the mind? But if this is the case why is it occurring across the whole society? It is as if every individual evolved the same way; as if (sloppy speaking) the same mutation is occurring in every individual.
Has the human species reached a level where the physical evolution is slowed down but the psychically evolution is ongoing collectively?
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Flynn Effect - seems to be more caused by more stimulating environment (mass education, plenty of complicated electronic stuff) than any genetic factors. Actually low IQ seems to be more evolutionarily beneficial, as it raises the likelihood of pregnancy due to lack of forethought about consequences of unprotected sex.
Nevertheless there are areas in which evolution is still working:
-Obesity epidemics - it eliminates genes predisposing to diabetes and overpressure. Impact is especially acute in areas when surplus of food is new phenomena, in Europe this process was partially spread to last few centuries.
-Alcohol tolerance - last tribes on many continents (Aborigines, US Natives, Siberian tribes) suffer from alcohol addiction in more acute way than the Westerns do. It seems that such genes were actually partially already wed out from the West.
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# Yes we are
A simple example: [lactase persistence](https://en.wikipedia.org/wiki/Lactase_persistence), i.e. the ability for adult humans to drink milk is only 7 500 years old.
Do note though that presently it is hard to surmise what our evolutionary pressures are, because our society and our standard of living has changed radically in the past 200 years, which in evolutionary terms is a mere eye-blink for a species that procreate as slowly as humans. [Evolutionary pressures](https://en.wikipedia.org/wiki/Evolutionary_pressure) that existed 7 500 years ago are gone. Others — artificial and natural — may have taken their place.
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Evolution is what works not what's better... evolution doesn't equal an upgrade, If great intelligence is needed to survive then ok it will eventually evolve, if however people can have sex and reproduce even if they are stupid then intelligence will be less and less important until it disappears completely. The stupid people will reproduce more than the smart ones, outnumber them and eventually the intelligent individuals will go extinct either by not reproducing or because like the stupid ones will start killing them.
This is what happened in the last 200'000 years of human history, stupid people always killed smarter ones...fortunately the situation is starting to get balanced today because stupid people have less sources of food and wage more wars against intelligent people that today have better weapons to defend themselves.
So if we are lucky stupid people will eventually start a war that will kill them all at once. And then humanity will start to evolve based on who is more intelligent not on who has more kids, because of technology and not nature....
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Humanity is still evolving, but not in the direction many would like.
Statistics show that in first-world countries, the most educated people have the least amount of children. The reason is that our society pressures well-educated people to plan their life around their professional career and not around their family planning.
Education usually correlates with intelligence and ambition, so we are currently breeding to lower these traits.
The trend is declining recently, at least in the United States, but still visible:
[](https://i.stack.imgur.com/yoq6M.png)
Image source: <http://www.theatlantic.com/sexes/archive/2013/02/lets-not-panic-over-women-with-more-education-having-fewer-kids/273070/>
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I think the concept that intelligent people breed intelligent offspring is faulty at best. I think on the whole intelligence fits the bell curve regardless of the parents. That said "dumb" people breeding will likely produce just as many "intelligent" people as it always has. The distinguishing factor is access to education. So, are we evolving? Absolutely. Are the evolutionary pressures the same as they were in the past? No. Technology has made the struggle to survive much less so the traits people look for in a mate have changed from finding someone good at survival to someone that is physically, emotionally and psychologically pleasing to the other person. What type of people will this create in the future? [Travel there](http://science.howstuffworks.com/science-vs-myth/everyday-myths/time-travel1.htm) and find out.
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Sure it still works the old way. The selection pressure may not be very high in the developed world, but if you think about it that's how you'd expect the interesting things to be able to happen.
If almost everyone can breed, traits with apparently negative value can spread, and may mutate to new traits on a path different from the currently apparently positive traits. If selection becomes more important again, who's to say what trait is going to be the good one? You never know, hemophilia may be the answer to the next big problem our species faces.
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So there's a planet that is used as a farming world (food) for its system. This planet has a single, Mediterranean sea-sized ocean on it and lacks any other major surface oceans (he hasn't excluded rivers and lakes). Is there any way, given these parameters, for a water cycle that is vigorous enough to sustain farming exist in this world? Can the balance of temperature from day to night in this world be maintained without any surface oceans to balance things? I'm having a hard time figuring out how this planet can work as it's written.
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## The water cycle is maintained by the abundant plant life
For there to be somewhat abundant water but no major oceans, there needs to be another place where water collects. This could be a porous layer of rock covering all the lower altitude areas of the (very flat) world.
The native plants would then likely have very deep root systems to access that water and bring it up to the leaves, where it would evaporate during the day as a way to cool the plant. (Days would be hotter and nights colder on a world without oceans). The evaporated water will form clouds, which protect the plants somewhat from the cold during the night.
This makes sense from an evolutionary perspective because the circumstances are very different. On Earth, water shortages are more pressing than temperature variations, so plants have pores that can be closed, fatty layers and of course the ability to shed leaves when there is no water.
The plants on this world would have none of that, because of the essentially unlimited water supply and advantages of daytime evaporation cooling.
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While the temperature swings will be higher that doesn't make it impossible to live on. The areas of Earth that are the farthest from the ocean are still inhabited and certainly could be so with even more swing. You might not be able to grow terrestrial crops but local life could have evolved to survive the swings.
The water cycle is another matter--the only way I can see for this to be viable is if there's something that causes far more evaporation from that small ocean than Earth experiences. Perhaps that ocean is really a huge rift valley, complete with gobs of vulcanism. Note that this would make the water unsurvivable for land-based life.
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I'd say that depends on many aspects. Planet size, farming amount, amount of people living there. If the planet has a thick atmosphere and is hot enough and the air around is very moist, water could be drawn from the air and used for farming. The colder poles could contain the ocean water. Also the temperature drop from day to night would be minimal with a thick atmosphere.
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Perhaps this world has undergone at least some degree of terraforming. If this is a farming planet, efficient irrigation can make up for any shortcomings in the water cycle, including drawing up water from subterranean caches. Temperature regulation can also be addressed with use of solar reflectors in orbit.
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There are other ways for a water cycle to work, the first that comes to mind being that most of the water is trapped just below the surface, thus allowing wells to be dug and used for irrigation.
Part of answering this would be to know what vegetation is like naturally on the planet. Presuming the inhabitants are native, they could only farm if plants existed naturally, so they would likely expound on whatever natural principles the world uses.
If the inhabitants transplanted from another planet, I would expect they would have technological capabilities that might allow it, and would have brought seeds from plants whose growth requirements they would know.
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With enough topsoil and soil water to form a reservoir and enough plant life for evapotranspiration you could have a reasonably normal water cycle, somewhat similar to the Amazon Basin where water evaporated by the forest during the day falls back to earth in the evenings in a continuous semi-closed cycle where the average elapse time for cloud water is measured in hours.
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The planet in question is Earth-like in size and composition and orbits a Sun-like star. Its atmosphere is less than 5% Oxygen and plants (lichens, some grass and river vegetation) have started colonizing parts of its surface.
## How would bodies decompose in this environment?
The bodies are either human or animal and at the time of death contain as much bacteria and wear roughly the same kind of clothes as they would have on Earth.
I'm curious to know if they would rot, dry or stay somewhat *"preserved"*, during a time period of at least one month.
A few types of terrains interest me particularly:
* Rocky plains with no vegetation, strong winds, plenty of sunlight and regular rains (1-3 times a week).
* Bottom of a canyon, next to a river, protected from winds and receiving barely any sunlight.
* Dry cave, no rain, wind, or sunlight.
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**EDIT** :
There is ***no fauna*** on the surface - only in oceans and rivers.
The time period should be at least one month and can be as long as needed for the process (rotting, drying, or other) to be well-advanced. I'm not particularly interested on what would happen to the bodies after centuries or millennia.
The mentioned terrains are in a temperate climate, with temperatures varying between 15°C and 35°C.
If someone can give a general answer including other climates and types of terrains, it would be appreciated.
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Other questions related to the same setting (if you want more details, but they shouldn't be needed to understand/answer this one):
[Space wizards city: Is it sustainable?](//worldbuilding.stackexchange.com/questions/39775/space-wizards-city-is-it-sustainable)
[How should the Magic market be regulated?](//worldbuilding.stackexchange.com/questions/39875/how-should-the-magic-market-be-regulated)
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tl;dr: The corpses would still decay, but probably much slower.
From the [Wikipedia article about decomposition:](https://en.wikipedia.org/wiki/Decomposition)
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> Decomposition begins at the moment of death, caused by two factors: autolysis, the breaking down of tissues by the body's own internal chemicals and enzymes, and putrefaction, the breakdown of tissues by bacteria. These processes release gases, such as cadaverine and putrescine, that are the chief source of the unmistakably putrid odor of decaying animal tissue.
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Clearly autolysis would happen also on that planet. So the question is which, if any, of the necessary bacteria and fungi are likely available (from your assumptions, animals aren't).
Wikipedia goes more on detail on the different stages:
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> Five general stages are used to describe the process of decomposition in vertebrate animals: fresh, bloat, active and advanced decay, and dry/remains.
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For the fresh stage, especially the following paragraph is interesting for your question:
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> The small amount of oxygen remaining in the body is quickly depleted by cellular metabolism and aerobic microbes naturally present in respiratory and gastrointestinal tracts, creating an ideal environment for the proliferation of anaerobic organisms. These multiply, consuming the body's carbohydrates, lipids, and proteins, to produce a variety of substances including propionic acid, lactic acid, methane, hydrogen sulfide and ammonia. The process of microbial proliferation within a body is referred to as putrefaction and leads to the second stage of decomposition, known as bloat.
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With your low-oxygen environment (which probably was once a no-oxygen environment) I'd expect especially the anaerobic bacteria to thrive, therefore I'd expect the body to at least go to the phase of bloat.
The description of the bloat phase in the Wikipedia article should be relevant except for the last paragraph, which refers to insects/maggots.
The active decay phase is described as follows:
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> Active decay is characterized by the per of greatest mass loss. This loss occurs as a result of both the voracious feeding of maggots and the purging of decomposition fluids into the surrounding environment.[11] The purged fluids accumulate around the body and create a cadaver decomposition island (CDI). Liquefaction of tissues and disintegration become apparent during this time and strong odors persist.[6] The end of active decay is signaled by the migration of maggots away from the body to pupate.
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Now the maggots would not be there in your environment, therefore I'd expect the active decay phase to be much less active. However note that the purging of decomposition fluids should happen also in your environment.
So in summary, I'd say you'd certainly go into the bloat phase, and you'd probably get a decomposition phase, but not as fast as on earth.
For your cave scenario, also the following paragraph seems relevant:
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> A body buried in a sufficiently dry environment may be well preserved for decades. This was observed in the case for murdered civil rights activist Medgar Evers, who was found to be almost perfectly preserved over 30 years after his death, permitting an accurate autopsy when the case of his murder was re-opened in the 1990s.
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I guess the burying part is only for preventing access by animals, which means the same should be true for the dry cave scenario.
[This page](http://www.exploreforensics.co.uk/the-rate-of-decay-in-a-corpse.html) also contains relevant information:
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Clearly those intestine bacteria would be present also in humans on your planet, as without them the humans couldn't live to begin with.
Also on [this page](http://aboutforensics.co.uk/decomposition/) there's a hint that lack of oxygen slows down decomposition:
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Giving a general answer is difficult, so you are actually free to make up a lot of this stuff yourself.
[The Wikipedia page on Decomposition](https://en.wikipedia.org/wiki/Decomposition) provides lots of information. What makes your planet a special case if that fauna, insects and animals are absent. This means that the decomposition will be driven mostly by oxidation and chemical processes, and whatever microbes is present in the corpses when they die.
In your case you need to leave out all factors that animals, insects and plant do for a corpse on Earth. Depending on how much rain the corpses are subjected to, this will affect things.
But I would say that the unfortunate souls that find the dead ones will be treated to a fairly icky sight. Anaerobic decomposition (i.e. without much oxygen present) will probably dominate the decay. This means that they will be **gassy**, **bloated**, and **stink badly**.
If they are in environmental suits it will not seem bad at first... other than a very rotting look on their faces. But any attempt at autopsy will likely result in a stomach-churning experience.
In fact... [Mythbusters' experiment of leaving a corpse (of a pig) in a car](https://www.youtube.com/watch?v=AKiB3g9hgQg) is probably a very good analogy.
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I've designed a creature for my alien world that is a large apex predator known commonly as a wraith. It lives mostly in dense jungle and forest and uses stealth and ambush to catch its prey (it can take down creatures the size of a horse). Its senses include the contextually unimportant taste and touch, a sense of smell as strong as or slightly stronger than a dog and thermal sensors on its snout. The thermal is important, because it is completely blind (a result of its subterranean ancestry). Its hearing is also extremely sensitive, and can pick up high frequencies. The ears themselves are large and form a fixed tunnel that runs down the sides of the head (which is slightly elongated) from the brow.
I've contemplated adding echolocation to the wraith's arsenal, taking advantage of its sensitive hearing and reinforcing its spacial awareness, as well as giving it a powerful advantage against competition (as a disclaimer, it is part of group of blind predators, a majority of life isn't blind on this planet).
My question is, at which point does strong hearing stop being an advantage and start being a hindrance? (sudden loud noises damaging hearing, especially when human machinery comes close).
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First of all, note that echolocation may not be such a good idea for a predator, since whatever is the frequency a predator uses for it, its preys will ultimately evolve to ear it as well, and thus detect it. [Some insect actually do it to avoid bats](http://bioscience.oxfordjournals.org/content/51/7/570.full).
To go straight to the point, a more sensitive hearing may become a problem due to evolutionary factors. If your predator hear with high accuracy and sensitivity a wide range of frequencies, it must as well be very good at analysing the sounds it hears, otherwise it will have no advantages to hear that well.
Its prey may evolve strategies to confuse you predator, for example by emitting noise over a wide spectrum of frequencies or by living in (or even constructing) a place with complex acoustic (perhaps even symbiosis between an animal and a plant modelling the sounds, and in fact possibilities are endless).
To catch up with that evolution your wraith should get a better analysis of sounds, or in other words, a better brain. But better brain imply that you need more energy (thus food) to use it. At some point a better hearing may therefore become a problem : your improved brain cost you more food that it allows you to catch, and it would be more food-efficient to have a slightly worse brain with a smaller "maintenance" cost.
It is a bit counter-intuitive (for humans at least) to thing that being smarter may actually be an evolutionary disadvantage, but it makes sense (and it explains why there are still plenty of quite stupid animals out there, having sometimes no brain at all).
However the trade-off between brain improvement and energy needed is only one possible evolutionary trade-off. You may for example also argue that a better hearing need a more complex ear, and that a more complex ear is more fragile. So at some point the loss due to less reliability is bigger than the gain due to better sensitivity.
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Animals with good hearing may be more susceptible to hearing damage overall, but the exact amount may vary.
Hearing damage is caused when the vibrations from the sound waves damage the delicate equipment inside the ear. The reason we find loud noises painful and annoying is because our brain is telling us to get away from them before they damage our hearing. If the noise would not be damaging, it wouldn't bother us.
There are different ways of improving a creature's ability to hear, one of the simplest being improving the shape of the outer ear to funnel more sound into the ear and amplify it. Much like listening through a simple funnel, this by itself will make the creature more sensitive to noise. Cats and dogs may be more susceptible to loud noises than humans, for instance.
However, if the creature's hearing is so good at hearing that noises capable of damaging its hearing are common, it may evolve to have more durable structures inside the ear itself, without sacrificing sensitivity.
For example, bats have such good hearing that they would deafen themselves with their own echolocation calls, so they have a mechanism which automatically 'locks' their ear bones in place at the moment they send out a pulse. This means that a bat cannot hear its own cries, only the returning echo.
It is not unreasonable that a creature with particularly good hearing (and noisier prey) might have a reflex that automatically dulls its hearing when it detects a loud noise, functionally similar to clapping your hands over your ears, but using a mechanism that is in the ears themselves. It might also be able to voluntarily adjust its current noise sensitivity using muscles in the inner and outer ear, making itself more sensitive when it is hunting or alert.
If we're talking aliens, it might have a more efficient method. Maybe its eardrum is made out of something more durable than plain old skin, like a protein structurally similar to spider silk. This would allow it to remain sensitive all the time and still be less susceptible to hearing damage.
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Sensitivity, itself is never a hinderance. It is always useful to have more sensory input than less. However, what can be a hinderance is difficulties with powerful stimuli, like loud sounds.
The factor which is important here is dynamic range. What is the ratio between the loudest sound and the quietest sound a creature can hear. How can it adjust this balance? If a creature is capable of hearing a whisper at 100ft in the presence of a gunshot, because its eardrums are just that amazing, then there's no disadvantage to that hearing at all (other than perhaps the extra processing you'd have to do on the extra input).
This is often adjustable. Consider humans. We have three bones in our ears which transmit vibrations from the eardrum to the cochlea. The ear drum is fragile compared to, say, the rest of our skin, but it's actually pretty tough. It takes a pretty loud noise to rupture the ear drum. The cochlea, however, is a fine tuned instrument for teasing apart vibrations. It is not so tough, and easily saturated. Those three bones that transmit sound actually have muscles attached to them. Those muscles serve as an "automatic gain correction" system. In loud environments, they pull apart, decreasing their ability to transmit sound from the eardrum to the cochlea. In fact, they play a part in speech. Your vocal chords resonate your head quite a bit. They would be very loud if unchecked, so just before you start speaking, these muscles will engage to decrease the ear's sensitivity to your own voice!
A more advanced creature, dependent on sound, may instead have a cochlea that's got a larger dynamic range, permitting it to continue hearing without adjusting its own gain in more extreme situations.
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While I think there is a lot to be said for a predator having incredibly sensitive hearing being able to be traumatised or damaged by something like a much louder industrial noise created by humans, I can't see this working unless there was nothing that loud naturally occurring on this planet.
So this implies there is no thunder, no storms, no trees falling nearby etc.
That's a tricky one to argue. Anything that happens normally gets built into evolution.
So maybe look at the specific frequencies - could there be something new in the environment that now harms the creature. Again, this gives you the opportunity for human impact.
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There are three cyberpunk corporations. All of them engage in immoral criminal activities to raise funds, and they don't really have a choice...profit margins are tight, and we have to stay afloat in a declining economy. I run one of these cyberpunk corporations, and I'm fighting a long and bloody war against the other cyberpunk corporations for market share. That war is expensive, further driving me into crime to sustain the beast. It's an endless spiral of despair and chaos.
Obviously the government hates my criminal activities. Our feuds with the other corporations tend to lead to collateral damage and bring down property values. I already tried bribing governmental officials, and it worked...for a time. But after yet another terror bombing that killed innocent civilians, the government had given up accepting my bribes. Which was fair...we couldn't afford the bribes anyway.
The government have instead established a Police Agency dedicated to "fighting crime" (i.e, attacking all three cyberpunk corporations). This four-way war is bleeding our finances dry. We have killed some of their police officers. They have killed some of our corporate executives.
To keep our corporation alive, our accountants have requested that we try to get a government bailout. I can't let this corporation go bankrupt...I have worked here all my life, I support its ideological beliefs, and the perks are nice. But I can't stop killing police officers. I can't stop committing crimes. I can't negotiate away the corporation's "evilness", because doing so would take away valuable income that will keep the corporation afloat. But I am still willing to talk with the government, and work with them (at least temporarily). All I just need is money, money to survive the next day.
So how do I convince the government to give me a bailout?
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It's kinda lame, but the bail out would probably happen for the same reasons they did in the real world. Too big to fail.
Lets assume typical Mega-Corps size because you only have 3, though the lack of power seems to suggest otherwise. Haliburton employs 70,000 people currently and the US govt employs 2 million civil servants (and something like 20 million total, if you count all soldiers, elected officials etc.) Your company is going to employ at a minimum 5 million, in a small country like Britain. In America it would probably employ 50 million or more. In addition it's likely at least 80% of the major markets you compete in are taken up by yourself and the other corps. That means you have at least 15-30% market share in any given market.
A loss of 5 million jobs in a day would decimate any modern economy. The US lost 5 million jobs in the first 8 months during the Great Recession, and in 2 years lost only 8 million total. Think what would happen if that happened in a single day. As one of 3 corporations, you have probably a minimum of 15% of the work force, and up to a full third if you are the largest corporation. Losing 15% of a work force could bankrupt a nation.
Furthermore, your competitors will suck up your lost market share and become that much more powerful. Perhaps more powerful than the government itself, considering how weak the national economy is going to be. Your corporation falling may be all that's needed to start setting off a civil war that makes two corporate states.
Even if there are other corporations, and yours is a moderate sized corp, in a cyberpunk universe they are still meant to be employing hundreds of thousands. The hit to the national economy with you falling will be something no politician with any understanding of economics wants to risk. Especially when it will make the other two players just that more powerful.
One of the key aspects of a cyperpunk world is the intermingling of corporate and government affairs. This is a perfect example of how, despite hating the corporation, the government has a symbiotic relationship with it, one that they cannot destroy without destroying themselves. It explains why the government hasn't already shut the company down itself if it knows they are engaging in street warfare.
[Answer]
How do governments come to power in this world? If it's through any kind of elective democracy, you can take a cue from recent events and pull off an audacious maneuver—run for president yourself, then given your corporation a bailout.
Alternately, if you yourself are too highly visible to make this work, pick a lower-level executive who is deeply loyal to the corporation, bankroll his or her candidacy from behind the scenes, and have your stooge ride to power on populist pandering and revelations of corruption among the current elite. (You will, of course, have evidence of this corruption, since you're the one who paid the bribes to being with.)
Actually, just having a president in power is too little—to really make it work, you should bankroll stooges to run for office at all levels of the government, all across the country. It would be nice if you could get your puppets into all the major political parties so that any opposition has no single home to gather in. You won't have to bother bribing these stooges, because they're already loyal to you.
For maximum effect, you should hire one of those pathetic humanities majors, who are all homeless and starving in the ghettos of this cyberpunk world, to write a manifesto for your "movement". Use your money to spread this manifesto everywhere, but make it look like it spontaneously erupted from the grassroots. A little astroturfing will start a bandwagon effect among everyday Joe Sixpack types; they'll all get on board and support your "movement". You can leverage any media presence you might have—a few television personalities could do wonders for your manifesto. Think of how effective people like Rush Limbaugh, Glenn Beck, and Rachael Maddow are at spreading political ideas in the real world—if someone like that adopts a manifesto, no matter how ludicrous the ideas in it are, people will consider it. Once your manifesto is out there, have all your stooges start quoting from it and insisting that it represents "the real will of the people" or some similar nonsense. Even if no one listening knows anyone who actually buys this garbage, they'll assume that your stooges are telling the truth and there is in fact a group of people who believe in it out there somewhere.
Your "movement" should rail against the massive increase in police power represented by the special Police Agency. See if you can start a few demonstrations and get the police to violently suppress them. Then have your stooges go out and criticize this massive overreach of government power.
You can also stage "accidents" for particularly troublesome opponents. Some whiny do-gooder activist opposes bailing you out? Just arrange for a "random psychopath" to show up at her rally with ten guns and start shooting. Have all your candidates get up on the stage and lament the tragedy.
Once the government is full of your stooges and your "movement" has taken hold, you go to the government pleading for an end to the violence and admitting that your funds are running low. You agree to sign a treaty where you stop funding criminal acts and stop killing police officers, in return for a bailout which will let you reorganize so you don't need to rely on crime anymore. You should also probably tell the government your corporation will collapse without this bailout, and fund a few corrupt economists to make models that predict economic disaster if your corporation fails. Your stooges will argue on your behalf, and the people in your "movement" will support you.
Once the treaty is signed, you keep on funding criminal acts. Just do it discreetly. Use your bailout money to set up some shell corporations that can launder the money for you. If anyone in the government complains that you aren't living up to your treaty, have your stooges shout them down, and if that doesn't work, discredit them with a scandal or bump them off. A "terrorist cell" or "foreign crime syndicate" are ways to accomplish the latter, while an ill-advised night with an "underage girl" could accomplish the former.
If your stooges and your "movement" somehow get discredited, well, no one knew it was you funding them. After all, campaign donations are completely anonymous in this corrupt cyberpunk world, right? So just run a new class of stooges and start a new "movement", and you'll be good.
[Answer]
Blackmail!
Let some of your special troups find or create evidence of illegal activities of the politicians. They will give you your bailout in exchange for keeping that evidence confident.
If you are already doing criminal stuff, leverage it.
[Answer]
You need to negation, make a deal with the government, point a that the war is going no where and that the government involvement is only make things worse. So propose that instead of fight you join forces and take out the other cyberpunk corporations. sweeten the deal with by sighing a secret contract that will give the government access to your secret cyber weapon and human enhancements.
If some one in the government that isn't cooperating with this deal, then that take him out and frame it on the other corporations. Hopefully this will encourage them to team up with you against the other corporations
[Answer]
While Torisuda's law is especially audacious and awesome, I am not sure if it would fit into the story my author want to tell. I think the most probable solution to my dilemma is Akshat Mahajan's suggestion in the comments.
>
> Why not just kidnap a high-ranking government official and hold them to ransom?
>
>
>
Obviously, the government will still hate my evil corporation afterwards (as per usual), but will still be tempted to pay the bailout anyway (they don't like seeing their own officials get killed, even if they are willing to let police officers get massacred). The main benefit of this approach is that I'm not bound by any deal whatsoever. I still can commit crimes without making people upset about me "not living up the end of my deal"...because, let's be honest, the only thing I promised is that I freed the government official that I just kidnapped. Didn't say I wouldn't try to assassinate him later on.
[Answer]
Since you are the leader you could do a few things, you are the bad guys after all.
I have made some assumptions
1) you have some arsenal so you can attack if needed or defend.
2) You have some money but not enough to get you pass 3 months or so.
3)This 4-Man war is at a stalemate and all 4 side are rough matched and one wrong move means you lose
If any of these are wrong please correct me.
---
## Threaten the Government directly - a physical attack on their person or property
You have already shown that you can cause a lot of damage to local property and you can say that you are going to "step it up" unless you get the money you need, depending on how tight your finances are this could just be a big bluff however you can follow it up with some form of speech that says you would rather not cause more damage then needed as you love this city etc etc.
[**Optional**] After you have given the threat back it up a little by either killing a few Government officials, the higher their rank and the closer they are to the top brass the better.
[**Optional**] Bomb the local police station. Depending on how strict the Government is enforcing this "Fight against Crime" policy and who enforces it, if the police enforce the policy a direct attack on them will show them how serious the organized crime is
---
## Threaten the Government passively - Threaten giving up (It is explained below)
This is likely a path you won't go down but I feel I should mention it.
Tell the Government that due to some issue (Don't mention what the issues are) you can no longer fight a 4-man war and you will be conceding and giving up all your territory to another faction, if the Government is smart enough they should know that this will give one side a huge power boost, at that point you could mention you could fight a bit longer with a "Small" donation
Either one of two things can happen when doing this. The Governments backbone break and you can keep bleeding them dry of money (Free money, GOOD!, Can kill whoever you want, almost, MORE GOODs!), or you become a "dog" on a leash for the Government (Free Money, GOOD!, Can't kill people often, BAD!)
---
Ok so we have covered basic threatening there, all good? But what if this Government doesn't bow down to these threats I hear you say? That is a good question!
## Stir up trouble
Force action between the 2 other factions and the Government and the goto the Government offering help (Bad guys turning good, how cliched), this doesn't mean you will help fight, far from it actually, tell the Government that you can talk to the other factions and get them to not attack you (for now) for a certain price of course. If they reject your gracious offer then let them fight after the dust settles pick off the weakened forces and absorb what they have left over increasing you earnings 3 fold, potentially.
If you help the Government then you can drip feed them false information about what the other 2 factions are saying and keep trying to bleed the Government dry. If you let the them all go to war then you need to be able to finish the survivor off quickly else they may recovery and bite back hard
---
There are other methods beside these of course, Blackmailing officials with their dirty secrets for instance, kidnapping beloved relatives, mass attacking local home/business, leak information to the public media about false crimes the Government has committed and covered up, the list goes on but the ones I have explained are the ones I would do in a situation like this.
[Answer]
Threaten their economy. If the government works on a market economy connected to other economies, you can threaten to outsource jobs enough to eliminate jobs from [the domestic workforce](https://www.investopedia.com/articles/personal-finance/082815/unintended-consequences-outsourcing.asp) and take money from said government. Threaten to take what money and resources you still have to some other corporate office in another country. If you have a trust or alliance with another business (or [blackmail due to corporate espionage](https://www.csoonline.com/article/3285726/what-is-corporate-espionage-inside-the-murky-world-of-private-spying.html#:%7E:text=Corporate%20espionage%20%E2%80%94%20sometimes%20also%20called,to%20get%20information%20about%20another.)), make other businesses threaten to do the same thing and collapse the national economy to force the government to play ball.
] |
[Question]
[
**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
**For my story, I need to know the following:**
---
I have a (*long exposure*) analog (as in "*not digital*") picture of the night sky taken on a random planet somewhere in the Milky Way galaxy. I know it is theoretically possible, but can the coordinates of the planet (or at least the solar system) practically be determined with present astronomical knowledge and present or foreseeable near-future technology?
**Criteria:**
* The picture is taken with a *quality camera* with *long* (>minute) *exposure* on the most sensitive commercially available (as: it can be bought in stores) film.
* The camera is available and is in the same condition as when the picture was taken. (So lenses, aperture, etc. can be examined in a laboratory.) Also *all its settings are untouched*.
* I know a *very good estimate* (minutes resolution) of when the picture was taken. (In "real" time. Either no time dilation is in effect or the time frame is corrected with the time dilation.)
* I have *detailed information* of the atmospheric compounds of the planet. (In sake of simplicity lets assume it is Earth-like.)
* The picture could have been taken **anywhere** in the galaxy. (No light-cones/no information principle is in effect.)
* Only *present astronomical knowledge* can be used. (No pictures from outside the galaxy or from other stellar points.)
* Only *present* or *possible near-future* technology can be used. (Limited processing power, no sci-fi technology, only Earth-mounted/space telescopes etc.)
* The result is *extremely important*, so for a **limited** time (Hours, maybe days... You can't use all computers on Earth for decades.) *Every available resource on Earth* can be used.
**Edit:**
The story will take place on an (late XX.- early XXI. century) Earth-like planet (not Earth) but I skipped that part for simplicity's sake.
**Edit2:** (Thanks to Scott Downey)
We have a nice approximation of the rotating speed and no real info of the latitude. The photographer appeared by irregular means (like teleportation) and have only spent a few minutes on the planet surface.
[Answer]
The problem can be solved relatively quickly only if the photo happens to have an identifiable astronomical feature, such as a globular cluster, cepheid variable or something like one of the Magellanic Clouds visible. The more identifiable features that are in the picture the easier it will be to identify the location in space.
This means that the photo will only be useful in a relatively small volume of space inside the Milky Way galaxy. As you can see in the picture, only a small portion of the galaxy is visible to us. A photo that somehow was delivered from one of the other arms would have virtually no features that are visible to us except exogalactic features like the globular clusters and Magellanic Clouds, and the probability of enough of these being visible in a single photograph is extremely low.
[](https://i.stack.imgur.com/IFFbO.jpg)
You also mentioned that light cones and other issues are being ignored, so there will be an additional problem in locating your planet in the picture: you might have a general idea "where" the picture is taken from, if you can see the locations of two or more widely separated features like globular clusters and Magellanic Clouds, but you will still have the issue of "when" the picture was taken. If the picture comes from 30,000 LY away, then the stars are in the positions they were 30,000 years ago. Even in a galactic scale, there will be displacement due to the rotation of the galaxy, so the farther away the picture is from, the greater the amount of uncertainty due to "drift".
Thinking on a somewhat bigger scale, you could resolve some of these difficulties not with digital cameras, but with more pictures covering a wider area of the sky. A panoramic shot would be nice, and as mentioned in the comments, using an equatorial mount to counter the rotation of the planet would make this process far easier.
[Answer]
## Almost certainly "No"
Without a spectroscopic analysis or other measurement to tell us the distance of the objects present in the picture, it's generally not possible to determine the object's absolute magnitude. If you can't tell how bright it is or what its color is, then you can't tell which star you're seeing in the picture.
So the answer to the general case of "if you're plopped down on a random planet somewhere in the galaxy and want to know where you are from a photograph," the answer is "no."
## Under exceptional circumstances, "Possibly yes"
Let's say that your circumstances are not the general case. Let's say you do have some background knowledge of locations (e.g. you know you're on Earth at some point in the timeline and you want to know when - or you know you're near the Orion nebula), then your specific knowledge of the stars likely to be present and their probable brightness might make it so that you can figure out your location.
The answer to the special case of "you're stranded in a known general region of the galaxy and you want to know the specific star you're circling," is "possibly."
## Change the scenario, "Probably yes"
Let's alter the scenario a bit. Let's say your spaceship crashed with some basic astronomy tools present (such as a telescope, spectrometer, & database). Then you may be able to determine the spectrum of different stars, compare them with your database, and could reconstruct your location.
Assuming you have a telescope, spectrometer, and astronomical database ***that includes the stars in your current night sky***; the answer to the question of "if you and your spaceship are stranded on an unknown planet and you want to know its location," is probably "yes."
Let me re-emphasize that if you crashed in a location that can't see the stars in your astronomical database, then you're back to "No."
### Terminology
[**Hertzprung-Russell diagram**](https://en.wikipedia.org/wiki/Hertzsprung%E2%80%93Russell_diagram)
[](https://i.stack.imgur.com/P1MKT.png)
[**Spectroscope/spectrometer**](https://en.wikipedia.org/wiki/Optical_spectrometer)
[](https://i.stack.imgur.com/x9YeB.gif)
[**Star Spectra**](https://en.wikipedia.org/wiki/Stellar_classification) (what you'd see coming out of a spectroscope)
[](https://i.stack.imgur.com/33ejP.jpg)
The different spectra above show the different [metallicities of stars](https://en.wikipedia.org/wiki/Metallicity). The more spectral lines the more metal (anything other than hydrogen or helium) in the star (and the later generation, evolutionarily speaking, the star is from). Each star's spectral line has slightly different strength depending upon the abundance of that element in the star's photosphere. If your measurements are precise enough the spectral lines can act like a finger print uniquely identifying a star. I don't expect our stranded voyagers to have the equipment or expertise necessary to be able to do that though.
[**Absolute Magnitude**](https://en.wikipedia.org/wiki/Absolute_magnitude)
$$M\_{abs} = m - 5 \cdot \left(\left(\text{log}\_{10}D\_L\right) - 1 \right)$$
The problem is we don't know the distance ($D\_L$) or the absolute brightness ($M\_{abs}$). Using the star spectra and checking the Hertzprung-Russell diagram we can make a highly educated guess as to the approximate absolute magnitude - which means we can get a ballpark guess as to the distance to the given celestial object.
] |
[Question]
[
After the adoption of Christianity as the one official religion in late Ancient Rome, the new role of pope inherited some duties of previous leaders, among them he’s responsible for the calendar. The last time this authority was notably enacted was with the [reforms of Gregor XIII](https://en.wikipedia.org/wiki/Gregorian_calendar) in 1582, which changed the leap rule (+4/–100/+400) and the [Easter computus](https://en.wikipedia.org/wiki/Computus). The start of the year (when the year count is incremented) wasn’t decreed and the now canonic 1 January was adopted at very different times.
The [Roman calendar](https://en.wikipedia.org/wiki/Roman_calendar) used to have strong lunar properties but became more and more solar over time. Some things had become mere tradition so that they could be changed, which (among others, but most prominently) [Julius Caesar](https://en.wikipedia.org/wiki/Julian_calendar) did. This was not the only calendar that early Christianity developed with, however – the lunar [Hebrew calendar](https://en.wikipedia.org/wiki/Hebrew_calendar) in particular, due to its use by Jews, and the [Egyptian calendar](https://en.wikipedia.org/wiki/Egyptian_calendar) which informed the [Coptic calendar](https://en.wikipedia.org/wiki/Coptic_calendar) with its 12×30-day months and 5–6 extra days which is still in Christian use.
Except for short-lived solitary [French](https://en.wikipedia.org/wiki/French_Republican_Calendar) and [Russian](https://en.wikipedia.org/wiki/Soviet_calendar) revolutionary attempts, there has been no real [calendar reform](https://en.wikipedia.org/wiki/Calendar_reform) in over 400 years, at least in the Christian parts of the world. It was last tried with a global scope after WW2 with the [World Calendar](https://en.wikipedia.org/wiki/World_Calendar) and competing proposals, which finally failed due to religious concerns about days outside the week cycle. There have been some minor secular changes or additions mostly for business or technical purposes, especially the start of the week being Monday (not Sunday) in international standard [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) and its predecessors (which also effectively introduce a parallel [leap-weak calendar](https://en.wikipedia.org/wiki/ISO_week_dater)).
Since the date of Easter is not fixed within the civil calendar (and [still differs](https://en.wikipedia.org/wiki/Reform_of_the_date_of_Easter) between Western and Eastern churches) and most names and numbers seem arbitrary with lots of “heathen” heritage, I came to wonder:
**What design features would a truly and inherently Christian calendar exhibit?**
To me, the only things that seem to be required are a 7-day week (although additional sabbaths may be possible) and some way to associate Easter with a full moon around the Northern spring equinox. The names of pagan gods would not appear in month or day names.
Weekdays would likely be named according to Genesis events:
1. Day of Light and Dark (and Sun)
2. Day of Sky and Heaven (and Moon)
3. Day of Land and Water (and Earth)
4. Day of Air and Wind (and Birds and Fish)
5. Day of Animals and Spirits or Angels
6. Day of Mankind (and Life)
7. Day of Rest (and God), Sabbath
The names of the twelve months – albeit less or more possible, even none – could be derived from the Israelite tribes (i.e. Jacob’s sons) or from Jesus’s first apostles, but there may be better options.
Also, would it matter much when it was to be designed and implemented in an alternate timeline, e.g. around 0400 (~ 1st Council of Nicaea, split Roman Empire), 0800 (~ 2nd CoN, Charlemagne), 1200 (Europe christianized), 1600 (~ Gregor XIII, reformation, colonization) or 2000 (~ now)?
Disclosure: I’ve published earlier attempts of mine at [Wikia](http://calendars.wikia.com/wiki/Christian_Calendar).
[Answer]
## Months
Christians have put quite a bit of effort into getting the date of Easter right (though denominations disagree on what "right" is), so any calendar reform is going to have to preserve that. There are two competing goals here: getting the right *date*, and getting it to *fall on a Sunday*. These goals are incompatible most of the time, hence the computations involving full moons and equinoxes.
Even while keeping the Sunday goal, the church *could* have made their calculations easier by saying "first Sunday after 14 (or 15) Nisan", the date on the Hebrew calendar on which the historical event is said to have occurred. Instead, though, the rule is based on the first full moon after the vernal equinox. Why not follow the Hebrew calendar? Partly because the early church wanted to distinguish itself from what came before (consider "old testament" and the theology that it's less important now), and partly because the church would be unlikely to want to tie itself to a system/group that it has at times been extremely hostile toward. You don't want to use the other group's system that you're trying to move away from; you want your own system. Unless these aspects of the church have changed in your alternate history, we should therefore assume that the Christian calendar will continue to avoid using the Hebrew calendar as a basis.
But you are still likely to have the concept of *months*. They're convenient in a way that "week 37" (or whatever) isn't. Lunar cycles are visible signposts of the passage of time. And the bible talks about *new moons* as significant days (though there is some dispute about how much of which parts of the Hebrew bible Christianity would care about).
I think it plausible that a new Christian calendar would develop its *own* lunar calendar. There are at least two examples to look at, the Hebrew calendar and the Muslim calendar -- the difference between the two is that the former uses leap-months to keep special days in their proper seasons (a solar-adjusted lunar calendar), while the latter is purely lunar. As far as I understand, Christianity has only two important dates that need to stay in their proper seasons, so they could adopt a pure-lunar calendar with the *seasons* of Easter and Christmas fixed, rather than their *months*. Or they could implement something similar to the Hebrew calendar, but they'd call it something different.
If you don't care about the *month names* for the holidays -- if Easter doesn't have to be in "April" or "Nisan" but just needs to be in the northern spring -- then you are free to have any number of months you want, though to approximately align them with the year you'll need 12 or 13. What would they name them? One possibility is "first month", "second month", etc, particularly if those turn into single words in Latin or Greek. "First month" should probably be the month containing Easter, since that's the transformative event of Christianity. Another possibility is to name the months after the [disciples](https://en.wikipedia.org/wiki/Apostle_%28Christian%29#The_four_New_Testament_Gospels_and_The_Book_of_Acts). (I think that more likely than naming after the tribes of Israel, a connection that Christianity might want to downplay.) If you include Judas's replacement, you can even get up to 13, for those years when you need a 13th month. (Maybe the leap-moth is Judas, so doesn't show up as much.)
If we're naming months after disciples, one might ask, shouldn't we name one after their teacher/leader, Jesus? To some Christians using the name of their savior in casual conversations ("your dentist appointment is on Jesus 12th") would seem inappropriate, even [blasphemous](https://en.wikipedia.org/wiki/Thou_shalt_not_take_the_name_of_the_Lord_thy_God_in_vain), so I expect they would avoid doing so.
## Days
The seven-day week is fundamental to Christianity, based on the seven days of creation at the beginning of Genesis. We have a problem here, though; the seven days of creation culminate with the sabbath, Saturday, while Christianity's special day is Sunday, the "lord's day". (I'm not a church historian, but I've read that they originally celebrated the sabbath on Saturday, as do Jews, but then moved the focus to Sunday to distinguish their community. Plus, maybe that Easter thing.) This might mean that they won't want a close naming tie to the days of creation because it puts the emphasis on the wrong day. On the other hand, I have been told (h/t eques) that some Christians see Sunday as the beginning of a new creation-like cycle, so maybe that's ok. You'll have to figure out how this works in your world. Let's look at alternate schemes for day names.
You could instead look for a *different set of seven* to use as day names. I suggest you name the days after the [seven cardinal virtues](https://en.wikipedia.org/wiki/Seven_virtues), to keep Christian values front and center every day. (You could also consider [Paul's seven spiritual gifts](https://en.wikipedia.org/wiki/Spiritual_gift), but I don't think they're as widely known.)
## Example
Putting these ideas together, here is one possible calendar. (I don't know the significance of most of those disciples, so I haven't attempted a complete ordering.)
Days of the week:
* Chastity
* Diligence
* Patience
* Kindness
* Temperance ("good Friday" falls on Temperance, for abstinence)
* Charity
* Humility (the "lord's day")
Months of the year (not in order):
* Peter (contains Easter, because he figured prominently in the events there)
* John (contains Christmas, because some say he's the "beloved disciple" so he should get something special)
* Judas, when a leap month is needed; goes right before Peter/Easter month
* distribute the other nine original disciples and Judas's replacement as you like; I don't know if any of them have seasonal or sequential connections
[Answer]
Lets assume that this hypothetical calendar did do as the question suggest and have no months (after all, Genesis mentions seasons, days and years are created, not months).
Dates would be referred to with the number of the week and day, and weeks of the year would mark important masses and passing of seasons.
One problem with this is that the number of days a year (~365.25) is not evenly divisible by 7, and there would be one or two extra days per year that is "left over". Either a new year would not start on the first day of the first week every year (imagine if the year started on the 2nd of January), or one-two extra days would have their own tiny-week, or a year would consist of 52 weeks most years and a full leap-week every five or six years.
Some other ideas about a truly and inherently Christian calendar:
* Weekdays would be namned to suit the christian mythos (maybe naming the first day lightday since light was created on the first day, and/or a Johnsday after John the Baptist).
* The reason for christian easter can only have happened once, so it is possible the easter week (and the holy week and so on) would happen the same days every year. That is, given that we somehow know (or arbitrary decide) which year of the hebrew calendar that the crucifixion of Jesus happened, we can translate that years easter to a specific date in the hypothetical calendars corresponding year. Once we done that, the new date could potentially be used every year.
* The new year would either still be close to the birth of Jesus (such as the day itself, first of advent, or the epiphany) or close to (the-non-moving) easter.
[Answer]
It would be reasonable to name the days according to the Easter cycle. After all, Easter events are strictly attached to days, not dates.
For example, Russian name for Sunday is воскресенье (voskresenie, literally Resurrection).
In this line Monday may become Appearance (re: Thomas), Tuesday is Transfiguration (if I didn't miscalculate), Thursday shall be Ascension.
I am not that well versed to suggest other days.
PS: Russian for Saturday is суббота (subbota i.e. Sabbath).
[Answer]
>
> Weekdays would likely be named according to Genesis events:
>
>
> 1. Day of Light and Dark (and Sun)
> 2. Day of Sky and Heaven (and Moon)
> 3. Day of Land and Water (and Earth)
> 4. Day of Air and Wind (and Birds and Fish)
> 5. Day of Animals and Spirits or Angels
> 6. Day of Mankind (and Life)
> 7. Day of Rest (and God), Sabbath
>
>
>
When I look up the [Genesis creation narrative](https://en.wikipedia.org/wiki/Genesis_creation_narrative), it says that the Sun and Moon weren't created until the fourth day (Genesis 1:16). The waters and sky were created on the second day. What's your citation for them being created on the first and second days? I checked multiple online bibles (including Catholic and Latter Day Saints versions) and they were consistent on this. Similarly, the birds and fish were created on the fifth day; both animals and humanity were created on the six day.
It's worth noting that the Jewish calendar did not name any day other than the Sabbath. This may be why the Christians chose to use local names instead:
1. Sun day
2. Moon day
3. Tyr's day
4. Odin's day
5. Thor's day
6. Freya's day
7. Saturn's day
I leave it up to someone else to explain why they chose two heavenly objects, four Norse gods, and one Roman god.
If you want Christian English names rather than the Jewish numbers, an alternative naming:
1. Lightday
2. Skyday (also water)
3. Landday (also the seas)
4. Starsday (also the Sun and Moon)
5. Fishandfowlday
6. Lifeday (including the animals of the land, humans, and plants)
7. Restday
If you want your story to change the bible, that's fine, but you should say so explicitly. Your version certainly makes more sense than the original with its sourceless light and water world.
The numbered days of the week suggest that the month days might also be named as numbers. The Romans did. We still use September (7), October (8), November (9), and December (10) from the Roman calendar. Your Catholics could use those ten names plus Birth month and Resurrection month. Note that translating the bible out of Latin is a relatively modern thing. Latin was the priestly language for a thousand years of Christian history.
Superficially having twelve months and twelve apostles would seem to fit, but I don't see them ignoring Jesus that way. Both the birth and resurrection seem worthy of their own months compared to mere apostles. Even lesser miracles like walking on water and changing water into wine seem like they might be more important. So perhaps
1. Birth month
2. Wine month (water into wine)
3. Healing month (many occurrences)
4. Exorcism month (several occurrences)
5. Raising month (several occurrences)
6. Calm month (calming the storm and the apostles' fears)
7. Feeding month (the division of the loaves and fishes; catching 153 fish)
8. Waterwalking month (walk on water)
9. Coin month (sent Peter to catch a fish with a coin its mouth to pay their taxes)
10. Curse month (cursed a fig tree with no fruit)
11. Resurrection month
12. Ascension month
This divides the miracles into groups. Some are singular while others are repeated (most notably healing). I would say that Crucifixion day (Good Friday) would be the first day of winter, that is to say, around our December 22nd. That would allow Lazarus day (first day of summer) to occur near the end of Raising month.
Winter: Ascension; Birth; Wine
Spring: Healing; Exorcism; Raising
Summer: Calm; Feeding; Waterwalking
Fall: Coin; Curse; Resurrection
Each season might be associated with a Gospel apostle. Fall could be Matthew (taxes are collected in Coin); Winter could be Mark (the oldest gospel); Spring could be Luke; Summer could be John.
[Answer]
## There is no such thing as a 'purely Christian' calendar because there is no such thing as a 'purely Christian' religion.
All religions and cultures are heavily influenced by religions and cultures around them. If it wasn't for Christianity's adoption as the official religion of the Roman Empire, it would not have evolved in the way it did, and would have instead changed in ways we cannot predict. Christmas was drawn from pagan solstice celebrations. Easter was born from Passover and other spring fertility celebrations.
To remove the external influences from the calendar you first have to remove the external influences from Christianity itself, and once you do that you're left with nothing at all.
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It would be a lunar calendar based on the Jewish Calendar
Many Christian events are based around the timing of Easter which is closely tied to the Hebrew celebration of Passover. Easter happened on the first day after the Passover Sabbath. Since the Sabbath is always a Saturday then Easter is always a Sunday.
The Hebrew calendar already has the 7 day week and naming for the days and the lunar cycles.
Christians may have also carried over the idea of special years from the Old tenement commandments such as the Jubilee year (year of returning land and forgiving debts) as well as the numerous festivals and sacrifices prescribed in the old testament. All of which are based on this lunar calendar.
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In [this question](https://worldbuilding.stackexchange.com/q/25318/28) I asked about the lighting patterns from this system:
[](https://i.stack.imgur.com/UyIOs.png)
A really helpful answer there explained when the planet is getting how much illumination.
This question is about heat. On earth I have a pretty good sense of the temperature variations over the course of the year at different latitudes. I'm not sure how to work that out when there are two stars in play, one more distant but, hey, it's still a star and stars radiate heat. I want to make sure that most of my planet is inhabitable throughout the year, like Earth; it's ok if some regions (poles) are too hot (or too cold) during certain seasons. Note that at some times of the year the second star is not visible from the planet, though presumably some of its heat still gets there. At the point marked "max double-day", all points on the planet are getting continuous heat (no night).
Is heat simply a proportion of initial amount and distance, or is it more complicated? How important is the "time off" (night) in regulating temperature?
The size and class of the secondary star seem relevant. I want the secondary star to [cast enough light to matter on the planet, like to the level of a dreary rainy day](https://worldbuilding.stackexchange.com/q/25203/28) (not just moonlight levels of light). An answer there suggests that I could put the secondary star in a reflection nebula. Beyond that, the size and class of the secondary star are not yet determined -- I'm happy to work with anything that gives me the light I want without frying my planet.
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It's negligible. If star B is the same luminosity as star A but is at 20AU from the planet instead of 1AU, then it provides 1/400th as much heat as star A does. It's a simple inverse square law. It will light the planet pretty well, because our eyes are very sensitive, but it won't provide any appreciable heat.
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Heat is transmitted by photons in the IR spectrum (or reflected photons shifting to longer IR wavelengths), so the short answer is the amount of extra heat is proportionate to the amount of extra light the second star provides. In order to make any detailed calculations, we would need to know the orbital parameters of bot of the suns as well as the planet(s) to calculate the light curves, and also the size and spectral class of the second sun.
The effects might not be very dramatic at all. At the end of "2010: Odyssey 2", Sir Arthur C Clarke describes the view from Europa, where the stellaformed Jupiter has melted the ice and created a livable world. The distant Sol is the "cold sun", which provides illumination but not much else. On Earth, the Stellafomed Jupiter is mostly an annoyance for conservationists, who are trying to prevent the extinction of multiple species which rely of the 24hr diurnal cycle for reproduction (such as corral and various other marine species).
Once you have the parameters set, then the answers should be fairly easy to determine, since the heat will be in line with the amount of illumination the planet receives.
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Actually, since the [mass luminosity](https://en.wikipedia.org/wiki/Mass%E2%80%93luminosity_relation) relationship is to the 4th power, if star B had double the mass of star A it would have 16 times the luminosity. Now, 16/400 = 0.04, so you would get 4 percent of the heating of the sun. This actually could cause appreciable warming... note that it is postulated that a 10% increase in solar luminosity is enough to make the [Earth uninhabitable, perhaps even boiling the oceans](http://phys.org/news/2015-02-sun-wont-die-billion-years.html), due in part to runaway greenhouse effect.
Also, to add to the fun (?), a star that is double the mass of the Sun will be very, very hot, so will emit a lot more in the ultraviolet. So it's possible that that star would put as much ultraviolet light on the Earth as the sun, or maybe more. With twice the solar mass, you'd have a high-mass A star, with a surface temperature of about 10,000 K, as opposed to the sun with a surface temperature of around 5500 K.
On the other hand, you could make the far star be a small red dwarf, then you'd barely see it (it might only put out the illumination of the full moon). :)
OK, here is an answer. You want the light equivalent of an overcast day. That's [1% to 2% of full daylight](https://en.wikipedia.org/wiki/Daylight). At 20 AU, you will need a star that puts out 4 to 8 times the luminescence of the sun. Under typical mass/luminosity relationships, a star of mass 1.4 to 1.7 suns will do it. Those are fairly reasonable Type F stars, similar to Procyon A or Sigma Ceti. To get a couple billion year lifetime, go for the somewhat lighter end of the scale, unless you want the excitement of impending Red Giant status. :)
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I have a world where there are five guilds, each creating a semi-autonomous political entity over a region of the world. At one point, a single empire controlled the whole continent, but the empire's power has since waned and is now only a figurehead.
The guilds are based around common traits, so they did exist during the empire, however the empire did not allow guild leaders to rule politically. That is, governors ruled taxes, land, and the legal system, and the guild leaders tended to guild specific matters. Since the decline of the empire the governors have merged into the office of guild leaders.
**How would the guild leaders reclaim power without causing political upheaval?** Assume that the term of governor was for life unless the emperor appointed someone new. The office could be passed in a will, unless the emperor steps in.
Notes:
- The emperor would not willing appoint the guild leaders as governors as that would undermine his already waning power. However, he has no central army under his control, instead military power is situated under governors in the regions, so he has little control over vassal states (hence the figureheadship).
- I would like the guild leaders to either gain the official title of governor or for the post of governor to go away altogether.
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Slow and stead wins the race. It's easy to slowly have the culture change to have them gain power, these sort of changes happen all the time. Look at England and the queen, she has almost no real power now, the parliament slowly took over, and now of days no one *want* her to have real power.
In a subtler example look at the US federal vs state government. Originally the states had a massive amount of power, due to their distrust of large government and wish to keep their independent rule. Over time the federal government has become more and more in a position of power, states now rule themselves but are more willing to allow the federal government to enact rules that apply to them and/or look to the federal government to fund more of their projects. The federal government taxes are now a larger percentage of taxes paid compared to states as well. This is all subtle stuff, and you don't notice it unless you look way back to the beginning of the US and see the way things worked then how much we now are supportive of the federal government compared to their view of it then. This all happened without any major changes to the constitution, just minor changes and states sort of allowing the transition to happen as we started viewing ourselves less as a state citizen and more as a federal one.
The process doesn't have to create upheaval if it's slow. The guilds start doing more and more of the government's jobs, people start looking to the guild as the ones to get new projects done. To support this the guilds start charging some dues/fees that grow into full blown taxes. Over time people stop being willing to pay as much tax to the failing government, and the government lacks the power and force to try to compel them, so it slowly agrees to less and less taxes to avoid alienating it's citizens and encouraging a true revolt. Eventually the government has power similar to the queen of England and the guilds rule everything.
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**To prevent political upheaval, you simply move slowly and follow the trend.**
The decline of the emperor’s power is indicative of a slow, but effective increase in power and influence of the governors. His figurehead status means that a power shift has already happened — from the emperor to the regional rulers. The governors seem to have achieved this power by controlling the major components of regional order: armies, tax collection, and law. This will be the model that you should examine when crafting the next transition of power to the guilds.
With your setup you have rulers who are appointed for life. This creates a number of problems because attempting to dissolve these appointed positions will be met by hostility and eventual upheaval. As a result, your governors will also need to become figureheads.
To achieve this, you need only look to the concept of a guild. As a unified group of skilled laborers with a long history, they have a platform of influence throughout the empire. This influence will extend to high places and will be closely intertwined with critical aspects of governance such as trade, military armament, and food stocks. So in the same way that the governors controlled the tools for maintaining order, the guilds control the cogs underlying each region’s basic functions. By subtly moving these cogs in the desired direction, the guilds can control the empire from the bottom up without even requiring support from the governors.
In the long term, the guilds can use their influence to position friendly people in line for governorship. This will make their goals simpler and increase stability even more. Ultimately, they won’t want to dissolve these governor positions because they provide a crucial means for regional control. After all, figureheads make great scapegoats.
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Go with the flow. Don't make waves. But there's an additional detail: make sure the flow goes where you want it to go.
Look at how Emperor Palpatine comes to power in Star Wars. He doesn't declare himself emperor using his godlike powers of the force. No, he subtly and quietly shifts things behind the scene, until the day the senate body chooses to elect him, and he ever so humbly accepts the honor.
You say your emperor is unwilling to elect the guild leaders as governors. Your emperor clearly needs persuasion. You can't approach him outright, for that would give him grounds to strike you down. However, if he is as weak of a leader as you say, there will be strife in the world. The guild leaders merely need to shape the situation such that that strife weighs on the emperor's heart more than the loss of power would weigh on him. Then, they simply wait for the emperor to offer the solution to them, and graciously accept.
Is there no strife? Then maybe the emperor is stronger than you think he is, because in a peaceful kingdom, figure heads have real power. In such a case, you need to provide a character stronger than them to work with them, slowly losening the emperor's grip on the empire. That's a much harder storyline.
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In revolutionary warfare theory, the revolutionaries assume power by creating systems of parallel government that usurp the power of the "real" government. This is particularly easy where there is a weak government or a power vacuum has been created by something like a natural disaster or invasion. The Muslim Brotherhoods began their rise to power in Egypt when a devastating earthquake cause widespread chaos and the government was simply unable to respond. Brotherhood cells in local neighbourhoods gained legitimacy and built their power base by being the ones who were able and willing to step in and provide emergency aid and shelter to displaced people.
In many insurgencies, parallel governments provide a form of policing and justice (especially if the government police and courts are ineffective or corrupt), although their method of tax collection is often pretty dramatic (of course there are some extreme anti-stateists who would suggest that an insurgent sticking a gun in your face and a letter from the local tax office are functionally the same things...).
The Guilds can gradually become legitimate power centres by providing the sorts of services that the government "should" provide, and doing so in a reasonably effective and transparent manner. Replacing one sort of corrupt police and court with another, equally corrupt police force and court system is not likely to gain too many adherents, and unless the Guilds can literally suppress all opposition with an iron hand, this in itself will create the conditions for upheavals (imagine a third group decides to clean house and establish their own transparent police and court system in opposition to the guild and Imperial ones....). As many people have mentioned, this can be done in an evolutionary fashion and so gradually that few people will notice that contract arbitration is now done exclusively through Guild sanctioned courts rather than the Imperial one (for example).
The only real issue that might derail this process, outside of the obvious one of trying to be an illegitimate and corrupt alternative power centre, is defining what exactly "should" be the ambit of government. If the Guilds decide to intrude in business that is not traditionally the domain of governments (child rearing, to make an example), then they will probably generate opposition to that as well. The Taliban gained power in Afghanistan by promising to end the battles between competing Mujahideen warlords and implementing a "clean" government. Their first promise was kept (they defeated the feuding warlords), but their idea of a "clean" government and society was pretty extreme and people who *were* able to fight them did so. Guilds which overreach will also end up in the same situation.
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You say that the emperor wouldn't assign governorships to guild leaders because that would weaken his power. But to me it looks like the guild leaders aren't necessarily his biggest worry: it is the regional governors who have the armies, and perhaps it is only a matter of time before one of them decides to advance on the capital and take the Imperial throne for themselves.
What to do? Well, the guild leaders are also powerful, but they are a little more under the emperor's direct control. He can always re-appoint them after all, at least on paper, and a guild leader has much less motivation to storm the imperial palace than the regional governors. Perhaps by shifting the balance of power towards them the Emperor can safeguard his family's future. He knows that this will give the guild leaders much more power than his family, but it's still the best option. They'll become figureheads, but it's better to be alive figureheads than dead despots.
So, by a series of crafty interventions - an increase in funding here, a surprise reassignment of the governorship there - the emperor builds a stable society in which power is divided along the lines of the guilds' specialisations. The regional states are no longer a threat, and while the emperor's family have given up the power they once wielded, they are not only get to live but even get to keep the palace.
Of course you have to play around with the details to make this convincing, but the point is that if the emperor sees that his power is inevitably waning he might not desperately try to hold onto it, but might willingly choose to give the guild leaders power if that helps him avoid a worse fate.
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The guild leaders should be good citizens and help the emperors legally appointed governors to fulfil their duties in the best manner possible.
The governor, not being a local, might not know all the important people and issues. The guild leader should make sure that all the information he has about trustworthy and untrustworthy people, current and potential issues and ways to solve or prevent them is easily available to the governor. Naturally in a discreet and inoffensive manner, so that the governor won't feel like he is being imposed upon. But if a person affiliated with the guild happens to be talking with a person affiliated with the governor and the guild has helpful information about the topic it should be supplied in passing. And there is no harm in guiding such discussions towards pressing concerns.
To maximise the contact point the guild should also do its very best to help the governor connect with all the right people of his province socially. Find what interests the governor, his family and friends might have, arrange events catering to such interests and invite the interested people. It saves the governor and his inner circle the bother - and considerable expense - of trying to arrange such events themselves. This will allow them to fully focus in their duties to the empire and allow them easily and naturally access to all the information you think they should have. And more time they spend with reliable and trustworthy people, less time they will have to be exposed to untrustworthy people telling lies and falsehoods.
Naturally the help should extend beyond personal interests if needed. If the empire is really in decline and the central government is losing its grip, the governor might at times find himself in situations where the official resources available to him are simply insufficient to what must be done. At such time it is the civic duty of the guild and its leaders to help out behind the scenes with their own resources. Why should the soldiers keeping peace and order have to wait for their pay just because the imperial treasury is mired in corruption? The guild has money. Why should people starve when the guild can arrange imported food? Why should trade suffer from bad roads or piracy when the guild has resources to help the governor deal with it.
And more you help the governor, more time he will have for, not just enjoying his personal interests, but also to focus on the important things only he can do. Such as dealing with the imperial bureaucracy and making sure their inefficiency and corruption does not derail the smooth and efficient manner things work in the province thanks to the cooperation of all responsible parties.
Now in the unfortunate case the deterioration of the empire should continue, at some point there will no longer be any benefit for accepting the new governor the emperor sends. That is fine - all the soldiers and administrators already know the guild will pay their wages, just like they have always before. The people will know that the guild will take care of any issues that might arise, just like they always did.
For that matter it will probably not even be necessary to defy the empire by refusing the governor they send. If the ability of empire to maintain itself becomes compromised, it makes perfect sense to withdraw from some provinces in order to save resources and focus on securing the core of the empire. Obviously you do not want to leave a vacuum behind and it would be good to leave the province in hands of a reliable and cooperative party that can be trusted to keep that border safe. Typically the guild would be given control of the province for some period of time in exchange for a cash payment. If things get better the empire can reclaim the province. If not they will need the next payment more than another province to defend.
Even if control can't be bought outright. The empire should be willing to accept status quo of guild controlled provinces as long they are offered enough money, are treated with respect, and the cost of taking the provinces back by force would be impractical.
This establishes a safe, peaceful and mutually beneficial model for control of the provinces moving from the empire to the guilds. Nominally all the provinces would be part of the empire, of course. The Holy Roman Empire lasted a long time beyond the fall of Rome and even fall of Constantinople.
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We can rebuild him. We have the budget... but do we have the technology?
In the process of reviewing the proposed enhancements for the Six Billion Dollar Man the following was discovered:
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> **Enhancement**: Extended Voluntary Apnea
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> **Purpose**: Implanted device significantly extends the period which the subject may hold their breath while maintaining peak physical activity.
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> **Proposed Mechanism**: Excess oxygen is extracted from the blood and stored inside this device during periods of rest. When a decrease in blood oxygenation is detected, this device can fully oxygenate and remove CO2 to maintain subject operation. Collected CO2 is released and oxygen reserves are restored during next period of rest.
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> **Duration**: Unknown.
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> **Recovery Time**: Unknown.
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> **Feasibility**: Unknown.
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>
>
Please help fill in the blanks.
**Can such a device be constructed, assuming 2050's technology?** (Exponential increase in technological levels can be assumed.)
**If the device takes the volume of half of one lung, what kind of duration can be expected during full exertion? How long to fill the stores and expel the waste?**
[Answer]
Actually, you'd be better off not building an oxygen storage unit, but to build a reversible glucose-oxygen fuel cell. This would have the advantage that when it was doing its thing, not only would oxygen be supplied and $\text{CO}\_2$ removed, but glucose would also be supplied, making the recipient almost completely self-sufficient as long as its power supply held out.
If we have $$\text{C}\_6\text{H}\_{12}\text{O}\_6 + 6\text{O}\_2 \to 6\text{CO}\_2 + 6\text{H}\_2\text{O},\quad\Delta G = −2880 \text{ kJ per mol of } \text{C}\_6\text{H}\_{12}\text{O}\_6$$ then by reversing this and applying energy, we can turn carbon dioxide and water back into glucose and oxygen, using power stored in the converter implant or supplied externally via whatever means (induction?)
If we go by current trends in battery technology, [battery capacity doubles each 22 years](http://investorintel.com/technology-metals-intel/nixon-on-electric-dreams-and-moores-law-for-batteries/). From 2015 to 2050 is 35 years, so we'd expect 235/22 = 3 times the capacity in our best batteries. Current Li-ion batteries are 460kJ/kg or 827kJ/L, so we'd expect 1380kJ/kg or 2481kJ/L.
Given that the volume specified is 'half a lung', the total volume of the lungs is [about 6.16l in an average human](http://www.askdrwiki.com/mediawiki/index.php?title=Lung_volumes): (Total Lung Capacity + Physiologic Dead Volume), so half of one of two lungs would be about 1.54L.
Considering that our battery/fuel cell might have 0.04L of ancillary equipment and be 2/3 energy storage by volume, we'd have 1L of battery, capable of storing 2481kJ.
If we take a highly active 18-30 year old, 90 kg male, from [charts on this page](http://www.fao.org/docrep/007/y5686e/y5686e08.htm), we can see that the daily energy requirement is up to 18.8 MJ/day.
This means that 2.418MJ divided by 18.8MJ/day = 0.129 day, or 3 hours. By reducing energy consumption with total inactivity, this could conceivably be stretched out to six hours.
Recovery time would basically be the recharge time for the battery - it could be charged by using the glucose-oxygen fuel cell, or by external induction. There would be some waste heat, but the human body is very good at dealing with waste heat. It might recharge in as little as a quarter hour on external power, up to an hour if relying on glucose and oxygen.
It is not inconceivable that a reversible glucose/oxygen fuel cell could be invented by 2050, though it would be pretty bleeding-edge technology.
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I've thought about exactly that for a "mermaid" kind of power. How much oxygen does a human use? We need about 600 grams of oxygen per day, which is surprisingly little! Now *storing* that in a light and compact manner is the issue.
I looked up state of the art systems one time. There's some new stuff that absorbs oxygen remarkably well. But a quick check on Google:
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> the Vika system uses a canister containing about 1 liter (2.4 kg) of perchlorate to generate 600 liters (0.86 kg) of oxygen, enough for one person for one day
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>
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That's pretty good in the bulk department. What future developments might bring is being able to release it without too much waste heat, and in-situ recharging.
My rough idea uses a tube-shaped artificial organ in the abdomen that's about 1 liter in volume but shaped like coils so it's spread out to fit well. It plumbs the blood through and can release oxygen and absorb carbon dioxide, with a capacity of 1/3 of a day. But it takes a long time to recharge and has a limited number of cycles.
Meanwhile, a device replacing one lobe of the lung (that's 1/5, not half) allows for a much smaller capacity but rapid recovery when breathing. I figure 20 minute capacity under moderate exertion. Recovery speed is that it takes all the oxygen from 1/5 of the inhailed air. Exercise speeds recharging because you breathe more!
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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.
Suppose there was a ternary system where the stars are effectively identical in mass, luminosity, radius, etc. These three stars circle a central point rather than two orbiting a larger third. At this central point is a planet.
My questions:
1. Can this setup occur naturally (for example, a rogue planet is pulled into the center and held there by the combined gravity of the stars)?
2. Is this setup stable from the perspective of the stars (for example, will one be consumed by the others)?
3. Is this setup stable from the perspective of the planet (for example, the tidal forces of the stars balance out to leave the planet wracked, but whole)?
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What you describe is known as a [Klemplerer Rosette](http://en.wikipedia.org/wiki/Klemperer_rosette). The configuration can be any regular polygon (triangle, square, pentagon, hexagon, etc.).
The star positions can be made statically stable by orbiting them around their common center of gravity. The problem is that the configuration is [dynamically unstable](http://en.wikipedia.org/wiki/Klemperer_rosette#Instability) - meaning if anything juggles the positions, the bodies will not return to their proper places.
**Answers**
1. The configuration is unstable and will not occur naturally.
2. No, it is unstable and the stars will eventually collide or wander
off.
3. No.
But if actively managed with a powerful method of moving stars around, a super science civilization could maintain the configuration.
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Jim2B beat me to [the best answer](https://worldbuilding.stackexchange.com/questions/18270/a-planet-ringed-by-stars/18273#18273), but there are more solutions.
Analyzing a system like this is called the [three-body problem](http://en.wikipedia.org/wiki/Three-body_problem), a case of the [*n*-body problem](http://en.wikipedia.org/wiki/N-body_problem). There are not many stable solutions to it, which kind of stinks for anyone wanting more exotic setups, like you. In most cases, it's best if two bodies are much more massive than the third. There are, however, exceptions.
Exotic solutions have been found ([some recent ones are here](http://phys.org/news/2013-03-physics-duo-solutions-newtonian-three-body.html); the paper is [here](http://arxiv.org/abs/1303.0181)), and these could be what you want. But they're awfully complicated.
Simpler solutions are given [here](http://www.ams.org/samplings/feature-column/fcarc-orbits1). Trojan asteroids participate in such a system, but their mass is much less than that of Jupiter, let along the Sun. A non-trivial, very interesting one is [the figure eight](http://www.ams.org/samplings/feature-column/fcarc-orbits2), in which three bodies of approximately equal mass travel in a shared orbit in the shape of a lemniscate.
Here's a gif, just for the fun of it:
[](https://i.stack.imgur.com/nklSf.gif)
You could have a planet that orbits in a straight line perpendicular to the plane, with a modified period such that it would not collide with any of the stars. That type of planet has been mentioned once before on Worldbuilding, though I can't recall its name.
This would be unlikely to form in nature, just as a Klemperer rosette would be unlikely to form.
# The answers:
1. Not really.
2. Well, none will be "consumed by the others" unless there is a collision, but a small perturbation could throw the system off.
3. I have no idea, though I'd wager not. It sounds like I have a new summer project, though.
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Perhaps one of the more exotic but still possible outcomes would be something like this, where if you imagine the earth is a star (a small one) and the sun is a star (a larger one), and 3753 Cruithne is the planet in orbital resonance with the smaller star. This might, (just maybe) have a survivable and mostly stable orbit where the 2 stars - certainly the smaller star would have odd movement. The seasons would be entertaining.
<http://en.wikipedia.org/wiki/3753_Cruithne>
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For the sake of simplicity, we will use 1200's Medieval Paris as an example. The city has walls 40 feet high and the initial defending army (army A) is 1500 strong. The attacking army has to breach the city and storm it. The citizen militia in the city equate to another 800 ill-equipped defenders.
It **HAS TO BE TAKEN BY STORM!** My attacking army (army B) has tried breaching the catacombs running under the city but the elite knights of Army A are stationed there and they are unable to advance. They tried bribery but the last umpteen attempts by treacherous Army A soldiers have been caught and the traitors promptly killed.
**How do many men do I need to breach the walls by force?**
**EDIT:**
Army B has 3 trebuchets, 10 onagers, 2 battering rams, and a team of sappers as well as a single siege tower set up.
They have 1000 scaling ladders (the defenders are prone to catching them on fire) so they have many in reserve.
A large relief force of 2500 knights is approaching and will arrive in two or three days. After breaching the city the attackers must hold it indefinitely. It has ample food stocked away (another reason a siege wouldn't work)
The following map is a general overview of the battle:
[Answer]
I think this sounds like a multi-step question:
* Step 1: Surround the city with your forces to prevent reinforcement
or escape. If you expect a relief force, you need double walls to keep the besieged army in and the relief army out ([circumvallation and contravallation](http://en.wikipedia.org/wiki/Investment_%28military%29)).
* Step 2: Create a breach in the walls.
* Step 3: Actually storm the city through the breach.
* Step 4: Hold the city down after the initial storming.
Step 1 will require a large force, much larger than the 1,500 defenders.
For Step 2, the siege engines are all helpful, but much depends on the size of the trebuchets, the thickness and quality of the walls, the countermeasures of the defenders, and so on. A week or more, perhaps much more.
* Do the defenders have trebuchets on the turrets of their city wall? If so, the extra height should give them a nice range advantage. Setting up siege engines will be a long and costly business.
* Unless the attackers are able to build larger trebuchets than the defenders, that is. Then they might be able to fire from impunity unless the defenders [sally](http://en.wikipedia.org/wiki/Sortie). That's why you can't use all the attackers to haul logs or stones for the trebuchets.
* It might be most efficient to dig a tunnel (a "[mine](http://en.wikipedia.org/wiki/Mining_%28military%29)") under a turret or the wall and to light a fire to topple it. This will take weeks or months, but at least the miners won't be under fire from the walls. There might be countermines, however.
* Battering rams only work if they can be roofed to prevent fire from the walls, or if archers can suppress the walls. The latter is mostly cinematic.
While the attackers try to create that breach, the defenders can tell where the attack will be coming. (Unless the attackers create multiple breaches to keep the defenders guessing.) So they can prepare. That brings us to Step 3:
* The attackers are climbing up a rubble-strewn slope, and through a narrow opening. The first heroic knight can expect a crossbow bolt. And the second.
* But sooner or later one of the storming party will live long enough so that the man behind him can reach a defender. One down, 1,499 to go.
A slightly later era got us the terms [forlorn hope](http://en.wikipedia.org/wiki/Forlorn_hope) and [practicable breach](http://en.wikipedia.org/wiki/Siege_of_Badajoz_%281812%29#Aftermath). Firearms would make it even more bloody, but the principle holds.
Historically, the result of the storming would be a [sack](http://en.wikipedia.org/wiki/Sack_of_Magdeburg) (again a slightly later example).
Afterwards, you have to hold the city down. The numbers for that depend on the civilian population and their attitude.
**TL;DR** if trickery failed and you have just three days, you can forget about the trebuchets and rams. Those thousand ladders and a real lot of casualties are the way to go.
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Based on the current information I am seeing, army B may be able to take the city and hold it with about 1000 men.
Note that at current time of answer, op has requested that defenders are spaced evenly along the wall, with ~100 men at each gate. This tells me that there is limited space on the walls, and it's more effective to rush a single point than to try and fight all the defending soldiers at once.
With siege engines, which can take down castle walls easily, all you have to do is focus fire. This allows for multiple strategic responses.
Assuming worst case scenario where in 2 days, you'll be crushed by 2500 knights, you need to capture the castle within a day and a half so that you have at least a half day to prepare for the oncoming enemies.
Step one: **Focus fire**
You have trebuchets and onagers - use them. Other than 2 onagers, focus all projectiles on one point of the wall. By doing so, you open up several scenarios. With the other 2 onagers, put one on each gate and task it to block the gate with boulders so that no one can escape from the castle.
Important thing to remember: the elite troops of Army A are in the catacombs! They're not on the walls! Optimally, we're going to assume that about 500 of them are elite soldiers and as such, only 1000 other troops are left on the walls.
1) Everyone on the defenders side goes to the wall to fix it as it gets destroyed
Your response: Now that everyone has left the opposite side of the castle, your siege tower (or ladders, whichever happens to be stealthier for you) is free to roll up to the wall. Send up 800 of the 1000 soldiers (Pick the most well trained) you have in your army. Your soldiers are now on the wall, and have free reign against archers (which would likely consist of most of the defenders on the wall, since archers are the most useful on walls/in towers (which doesn't seem like the city has any)) and other soldiers. Because most of the enemy will be trying to save the wall your machines are smacking away at, you'll effectively be able to cut them down from behind. I predict that 800 soldiers should be enough for this job simply because a) they won't be expecting it - demoralization is likely, as well as having their backs to you being a massive advantage. b) the numbers advantage is much less in a narrow corridor such as on a wall. As soon as that happens, it's likely that the enemy will drop what they're doing on the wall, and you can stop firing rocks. This is to allow your task force of 200 armored knights to storm inside and take out the 800 ill equipped defenders (assuming ill equipped means badly trained peasants with pitchforks/knives, etc). If the wall hasn't crumbled by this time, you have 2 options: You can either use the battering ram to get through the rest of the wall, or the sappers. This will be possible because everyone is busy fighting your 800 men on the walls.
2) Everyone on the defenders side runs away from the rocks to save themselves
Your response: Split your forces into 750 and 250 men. Stop firing your siege engines. Send 750 men up the side of the wall where the entire enemy force has congregated, and send 250 up the empty side (as quietly as you can). Use the battering rams and the siege tower as cover (and a fat distraction) - stall and distract the enemy force while your 250 men dispatches the enemy from the back. Then, you can take out the militia easily.
3) They don't do anything, the wall falls within an hour, they take massive casualties from the rocks hitting them while they stand on the walls, and you march your men through the wall.
The followup: Marching 1000 men through the wall can easily take out the 800 militia inside the city. At the same time, the rest of the troops have to get off the walls to fight you - archers can't fire into their own city for fear of killing their own people, soldiers on walls are out of range. This means there are now trickles of soldiers coming into the city from the walls, that you can cut down easily with some choke points in the city streets.
**Up till this point we've only covered what to do to storm the castle. Now, to hold it:**
OP has mentioned that he has sappers, and that there are catacombs below the city. What needs to be done now to hold the city consist of several things:
1) Seal off the catacombs. You don't want those "elite troops" to come up and cut you down. Dispatch some sappers and soldiers to seal off all entrances/exits of the catacombs. They'll starve/drown/suffocate to death down there. In fact, if at all possible during the siege process, you will want to do this step ASAP.
2) Fix the wall (if needed). If you put a hole in the wall, use your sappers to fit it. Better yet, booby trap it! Reinforce it if you can, you can take apart the siege tower/rams and use its parts to do so if necessary.
4) Set up the onagers on the walls, and the trebuchets in the city. Use them to attack enemy siege engines should they bring any, or to wreck general havoc on advancing forces.
3) Send a fast moving scout (or something like that) to your home country asking for reinforcements. This is almost the only way for you to survive indefinitely. When your help arrives, you can commence a pincer attack on the 2500 relief troops. Otherwise, you're in for a long wait until the relief troops leave....
Disclaimer: the above is a very rough strategy based on optimal conditions and responses - without more detail concerning the lays of the land, any obstacles, or troop count/types of the enemy, I cannot devise a more elaborate strategy. One of the main reasons this plan should work is because we know the status of the relief troops. Under normal circumstances, where we don't know if there will be relief troops, then the strategy would certainly involve many more people, such as in O.M's answer. However, since we already know it will take at least 2 days, we don't have to worry about it and can focus solely on taking the castle as fast as possible. While technically you should be able to hold the city for a while with the remaining surviving troops (probably about 600 if you got lucky) This is a bad guideline and you should probably send double or triple the amount of troops to guarantee success. Murphy's law: Anything that can go wrong, will go wrong...
**EDIT: After some discussion with friends, a second strategy requiring about 1200 men, but less distraction dependent**
Position the trebuchets such that the projectiles roll across the top of the gate area/battlements.
Instead of aiming for the walls, aim for the people on top. This accomplishes several things: 1) takes out troops on top of the wall 2) blocks off reinforcements to sections of wall (if your boulders stay on the wall).
In 1200 century, battering rams had roofs. This means you can send rams and sappers to the front gate to take it down quickly. The roofs also protect (a bit) from falling debris as your trebuchets wreck havoc on the gate area. Onagers can be used as a distraction, and as a terror tactic, lobbing rocks into the castle innards, hopefully taking out some of the militants.
As soon as you break through the gates, you have free reign on the militants, and as stated before, chokepoints can quickly dispatch any incoming trained soldiers as they leave the walls to defend their castle. Remember to send sappers out to seal the catacombs!
The 200 extra men are required b/c you're probably going to lose people moving the rams into place, and a frontal attack means you're likely to lose more soldiers since you don't have the element of surprise.
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Two to three days isn't long enough to breach the walls using the available technology, and is nowhere near long enough to siege the defenders out unless you can poison/destroy their water supply. Further, the need to hold the city against the relief force means either of these options will cause problems later.
This means your only option is to take the walls by storm. Given the limited siege train you've got (only one siege tower), most of your men will be going up via scaling ladders (and mostly coming right back down as the defenders push the ladders over). You'll also want to send the battering rams against the gates to force the enemy to divide their forces, but this is purely a feint: actually breaching the gates would leave the relief force with an easy way in.
Since you'll need to hold the city against the relief force, you can't get much use out of the artillery: because of the risk of hitting your own men, their only use in an assault is throwing incendiary projectiles into the city to further divide the defenders, and that rather limits your ability to hold the city afterwards.
A good rule of thumb when fighting in such unfavorable circumstances is that you need at least a five-to-one advantage in numbers, meaning a minimum of 7500 attackers. With this many soldiers, a second option for resolving the situation presents itself: leave a portion of the attacking army (around 1500) to keep the defenders penned up in the city, and march the rest out to defeat the relief force, as a two-to-one advantage is usually sufficient in the open field. Once that's done, you can settle in for a proper siege.
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The minimum number is hard to say, but here's what I'd suggest.
* Note: three days is not long enough to breach the walls using siege engines, at all.
* Even if you had a way to destroy the walls, you'd prefer to take the city intact, and use those intact defenses against the relief force.
What you want to do is gain the city before the relief force arrives, so your force needs to be strong enough to beat them once you are inside the city, and it needs to be strong enough so that your survivors from that battle will be enough to defeat the relief force while you are in the city. Use whatever size/strength estimates you trust to gauge the size needed, but probably at least twice the size of the relief force, or 5000 good men.
The most efficient way I can see to do this by force, is to take advantage of the size of the city, to split their forces, and then sneak in enough men to defeat them in battle in the streets.
Step 1: Scout, harass, and begin what appears to be an assault force concentrated near the northwest gate. Siege engines bombard that gate. Have scouts and skirmishers venturing all around the city, to appear that you are active in all directions.
Step 2: Start several diversionary feint attacks at night, at the northeast gate, and along the south west part of the city walls. Gauge the wind, and create smoke to spread through town, to reduce their situational awareness. Some groups have men using ladders to try to gain the walls. Have other men try to get into the gatehouses to open gates. Have a feint attack in the tunnels you mentioned. These are all diversionary attacks, however, not attacks in strength, but there should be adequate men in reserve so that if any of them meet with good fortune, you can send in a good-sized force through any means you manage to gain this way. The point is that in order to prevent you from getting a strong force into the city this way, and to respond, the defenders will need to spread their forces all around the city, everywhere but where you will concentrate your main force, which brings us to:
Step 3: After the diversion has attracted a lot of attention to moving groups spread out and not under their direct central command, the main attack uses boats and ladders and pours through the river opening coming downstream from the east. Advance the siege tower from Ab. St. Victor and have archers in it lend support to the river invasion. Secure "beachheads" as quickly as possible on the north and south bank and on the island with the bridges. Get as many men on the streets as fast as possible, and then defeat the enemy in general melee in town.
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Unless you have a cannon and you wouldn't for another 100 years then your only hope to take the city with walls that high and their own would be to either...
A) Leave a small force to hold the area around the city and
a1) Trick them into believing you have left to attack their reinforcements and then counter-attack them when they attack your men.
OR
a2) Trick them into believing you have left and are waiting for them to come out so you can attack them when actually you are going to attack their reinforcemnts.
The second option is B and much more sensible.
B) Concentrate your artillery on a specific point on their walls and open up a weak spot for your men to attack. Do it quickly, you only have 2 days at most. Expect the reinforcements to beat your expected time. Focus all your efforts on their best men and kill as many of their elite knights as possible.
The answer to your question is at least 7000 men before you even consider staying overnight. No logical commander would even think to attack a city without a three to one advantage especially when that advantage is trimmed within 3 days. With only 7000 men you will not be able to build a wall around such a large city like 1200 AD Paris because if you build your wall too close to the city their men will attack your men. Even if you had 7000 men against a city like Paris you would not attack it with such a large relief force expected within 3 days. Personally I would mix things up by entraping the knights in the catacombs, maybe paying off a local to figure where they enter and destroy the entrance once their inside. Then I would use my artillery to burn the city, then attack the walls. If the cities defenders have any type of artillery I would abandon the assault.
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Interesting...with the norm being to avoid pitched battles, maybe most pitched battles were a result of a withdrawn siege, if 2500 knights are coming to relieve the defending party, then you ultimately have two paths, take the city before the relief force or withdraw but risk both forces now joining which im sure they would pursue to eventually besiege them in turn which gives the initial attackers time to build up a bigger army...other than the brovado and kingly pitched battles, maybe most pitched battles were an escilated with the back and forth castle sieges, food for thought. For the question i wouldnt say theirs a particular set number of men needed to \*hold a city but rather how many are available, since it seems western european warfare takes on a byzantine reserve army strategy rather then the old roman frontier, so id guess about 1/3rd of available troops is enough, as holding cities and castles are temporary at least in the short time following, but after months or years, the numbers used to keep order would, rise and fall according to an infinite amount of factors of possibility and time, their just isnt a set number to conquor a city or fotress, it could be 1500 defenders, and you have 300 yet with cunning maybe a false letter tells of a force coming from a nearby castle with 3000 men, and then the defenders surrender, variables.
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Within my setting, there are [magical items](https://worldbuilding.stackexchange.com/questions/11781/how-would-i-limit-the-amount-of-magical-bling-a-person-could-wear). These magical items are created by affixing runes onto them. These rune are drawn with metal thread from various precious metals: copper, silver, gold, platinum etc. The runes are then instructions for magic, with the precious metals having innately a lot of Mana in them.
Here is where I need help. Right now, I justify the precious metals as being magical due to them having a generally similar properties. Be that as it may, feel free to include your own reasoning for precious metals being magical. However, I really want there to be magical crystals/gemstones. How should I then explain, in a way that is internally consistent, so that precious and expensive materials are highly magical?
Notes:
* The method of drawing metals into thread and writing with them to form runes is entirely inspired by the [Masterwork Dwarf Fortress mod.](http://www.bay12forums.com/smf/?topic=98196.0)
* I want materials that are precious and expensive in real life, except petroleum, to be magical, not the other way around of random magical materials being expensive because it is magical.
* While the precious metals are used in the form of runes, I would imagine that the gemstones/crystals would be simply placed on it, and it is carved with the same runes as the metals are drawn, and then it is magical as well
In other words, what do crystals, gemstones, and precious metals have in common?
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Since metals are operating in a different system than gems, out makes sense to say they contain different mechanics. When you talked about weaving runes with metal, the first thing that sprung to mind was electrical circuitry. Metal runes are basically inscribed circuits that provide magical integrated hardware! Gold, silver, and platinum are just the best magical semiconductors...
Gems are a little trickier. According to your post, they get inscribed but not inlaid. There are many gemstones and crystals that are semiprecious or common that would presumably have no magical properties, like quartz, salt, and amethyst. So it can't be pure crystalline structure. What else?
Well, all precious stones form under deep heat and pressure, mostly volcanic conditions. The earth's core is a massive magical source, and the deeper down a gem is formed, the more ambient magic is absorbed into its crystalline structure! Surface formations like salt and geodes would have little inherent magic.
Precious veined metals (rather than ores) are too amorphous to retain magic in their lodes, but are still attuned to magic which is how they can be woven into runes. These runes create effects by drawing magic from the ambient surroundings: the more magical the area, the more powerful the spell.
Precious gems work in the opposite manner: they are magical super capacitors and generators. Carving a rune into them allows you to control the external flow if magic. The larger the gem and the more flawless the crystalline structure, the more magical capacity the gem has and the more powerful it is.
So you have two complementing methods: woven metal runes generate magic from channeling external energies, precious gems from internal energies trapped during crystal formation further down toward the magical core of the planet.
***Update:***
With this system, you can have a REALLY crafty crafter who inscribes gems with runes and then weaves metallic runes AROUND them - the gold concentrating the magic of the gem even further! Perhaps by focusing the magical energies into coherence this creates a "magical laser?" Might it cause a feedback loop and result in a huge explosion? There are all sorts of ways to go with this one, though I pity the poor sod who's the first to try it out... They'll probably spend months scraping him off the walls...
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The key is **Patterns**.
All crystals and gemstones have repeated geometric patterns as part of their internal structure. You can decide that that structure is necessary or enhances magic. As a side effect, a more valuable crystal/gemstone means a better, more repeated pattern with fewer flaws. So you can justify more expensive stones being better for magic.
Precious metals are trickier. It is possible to put patterns into metal with repeated smithing - that's part of what makes forged objects stronger - but there's no obvious reason why gold would be better than say, bronze or iron for that purpose. There are a few things you could use, but they're a bit weaker:
1. **Affinities** - you could say that certain metals associate with different types of magic for Reasons. Say gold with fire, silver with darkness, etc - you get the idea.
2. **Numerology** - do some pseudoscience with the periodic table and figure out some special associations with the atomic number of the precious metals that common ones don't share. Then you can decide that that makes them special.
3. **Shared Magic** - maybe each metal on the planet has a total amount of magic, shared between all parts of that metal. Let's call this 1 Big Magic Unit (BMU). So all the gold on the planet = 1 BMU = all the iron on the planet in terms of magical potential. But because there's say, only 1/4th as much gold, that means each ounce of gold has 4 times more magic than each ounce of iron.
Edit: I realize now that you already have something for precious metals, but figure I'll leave the second section in since it doesn't hurt anything.
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I hate to answer by not answering the question (stack exchange tends to vote them down), but I think there's [another approach](http://brandonsanderson.com/sandersons-first-law/) which makes your job much easier.
**Sanderson's 1st rule of magic**
>
> Sanderson’s First Law of Magics: An author’s ability to solve conflict
> with magic is DIRECTLY PROPORTIONAL to how well the reader understands
> said magic.
>
>
>
As it turns out, you can get away with more vague connections between materials and their magical properties, so long as the readers are comfortable with it. This doesn't challenge any of the existing answers posted here, but it does point out that it matters less how you rationalize that things are magical, and more how consistently and predictably you treat it.
If you decide that silver and platinum have "similar" effects because they're both white metals, readers will expect that gold and copper also have "similar" effects because their hues are related. Some might even expect to see some magical properties in bronze. On the other hand, if you see a whole host of copper and silver magic items, with silver being more powerful, the reader won't think twice if your gold items are more powerful than that. If its the artificier's skill making the item that matters, they should expect ancient wooden trinkets hewn by legendary shamans of yore with more power than gold amulets made by average shamans of the day.
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You could start by relating the "magic" actual physical properties.
**Gems**
Gems are very hard, most gems are harder than steel by a wide margin. Assume magic causes "erosion" to the gem used to store it proportional to the magnitude of the desired effect. At that point the [Mohs hardness](http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness#Intermediate_hardness) of the material can be used to determine what magic it can hold.
You can add the limitation that the process of enchantment is light based so that the storage medium must be transparent to some degree to light of color related to the type of magic. Or alternately to colors other than that related to magic type.
You can make the "erosion" effect also specific to the process of enchantment, so that you can use any solid material to store any spell, but your chances of succeeding are proportional to the hardness of the material. Enchantment is generally assumed to be a time consuming process requiring specialized skills. It might be cost effective to pay more on materials to reduce the chance of failure.
**Metals**
If gems store the magic, the metal should shape it when released. Precious metals have some notable properties: conductivity, malleability, and corrosion resistance. They can efficiently conduct the magical energies without huge amounts of energy lost to potentially dangerous side effects. They can be shaped to the precise shapes needed for the runes. And the relase of magical energy does not cause them to corrode and lose magical potency as the runes get corroded from the surface.
With these proviso the optimal material would be gold plated silver or copper alloy. This would depend on the properties of the magical energy, silver has higher electric conductivity, copper thermal. (IIRC, not really important). Stone and organic materials would still be usable for lower "magic density" effects like permanent charms. Base metals could have corrosion resistan coating.
Again I think it is best to link this to the process of enchantment. If labor of shaping the runes is expensive, and it would, using a malleable, easy to work, precious metal makes sense. And a high conductivity metal might allow performing enchantment faster. And the corrosion resistance might drastically reduce the chance of failure and having to start the process from the beginning.
**Overall**
I guess the general idea is that if constructing magic items is time comsuming and requires specialized and expensive labor then using expensive materials that make work easier does make sense. And precious stones and metals actually do have good properties for this scenario.
Additionally, if magic items are expensive to start with, they would be commissioned by wealthy clients, who fully expect their expensive new toys to also look good with their expensive imported silks.
Also, related to ease of working the material, the tools fo working precious metals are much more enchanter friendly than a forge is.
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**I think conduction and resonance would be a good way.**
Metal is a great conductor, and doesn't actually contain the mana, but conducts the background mana that surrounds us all into a useful path.
The purity and type metal determine how well it conducts the mana energy.
In regards to electricity, Copper is a pretty good conductor. Gold has slightly less conductivity, but resists corrosion. Silver is the best conductor, but does corrode a little.
Here's a surprisingly interesting article about the conductivity of precious metals: <http://machinedesign.com/archive/materials-engineering-little-known-facts-about-precious-metals>
Mana can behave differently than electricity, so definitely feel free to assign your own rank for how powerful each metal is.
Metal by itself can and will pick up energy from the background energy, but not much.
To really do something you need a power source. Gems can be great resonators, depending on quality, cut, and any number of other things. The right gem with the right cut will resonate with the background mana, acting like a receiver. And so taking several high quality gems and linking them together with a quality precious metal in the right pattern would make circuits where mana energy is collected, channeled, stored, amplified, and harnessed to great effect.
<http://en.wikipedia.org/wiki/Crystal_radio> is an example of a crystal that draws power from radio waves and converts it into something else, in this case sound.
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They are magical simply because humans/sapients place value in them.
The collective subconscious assigns great value to precious metals and gems. This corresponds to humanity as a whole unconsciously placing mana in said precious things.
Mana as a thing flows from the collective subconscious to things held in high regard by humanity as a whole. This means people like kings etc have a large personal mana supply.
Particularly well crafted items admired by many has some for example the kings crown even was it not made of anything precious is coveted and so has some level of mana.
But by far the easiest way for an item to have a large mana supply means being constructed from precious metals/gems due to them being inherently valuable to almost everyone
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[Based on my previous question here,](https://worldbuilding.stackexchange.com/questions/10757/the-desert-of-ore-how-is-it-different-from-a-desert-of-sand) which a helpful other person pointed out, which would make the question too broad, here comes a different question for that.
Given a desert full of ore sand, what would be the kinds of flora and fauna that could live in such an area
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The mundane flora and fauna of any desert would be pretty similar to that of any reality-based desert unless there were magical reasons why they should not exist.
Since the desert is described as ore *sands*, we would expect much of it to be free-flowing [dunes](http://en.wikipedia.org/wiki/Dune). However, some ores may bind together into a cohesive mass when wetted (most deserts get *some* rain), so some ores may form more solid surfaces such as [desert pavement](http://en.wikipedia.org/wiki/Desert_pavement).
There is not usually much that lives in sand dunes. Smaller plants get buried by windblown sand, so such terrain may have only a few acacia-like trees or tall cacti and some insects and reptiles. Birds may visit from time to time, but would not stay long.
Where the ores have bound together due to occasional exposure to water, or the grain sizes are larger and not consistent, we would expect a desert pavement. More can grow in such an environment, so expect dry-climate cacti, trees and grasses, as well as dry-adapted insects, birds, mammals and reptiles.
Where the ore was toxic, we may still get the same vegetation (depending on the ore), but there may be a noticeable difference in appearance, and there would be fewer or no animals living there. Some ores that are particularly toxic (such as salt, cobalt or arsenic ores) may have little or no plants or animals growing there at all.
As to the magical creatures that might live there... who can say?
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As the other answers have pointed out, you're not going to have a lot of *Earth-normal* flora and fauna that will survive out on the ore sands. Heavy metal toxicity is pretty gnarly, and when it doesn't kill you quickly, it tends to sterilize you, so you're not going to be having a lot of offspring that might be slightly-more-adapted.
That said, there are such things on Earth as plants that [hyperaccumulate](http://www.ncbi.nlm.nih.gov/pubmed/21421358) heavy metals, enough so that there's discipline called "phytomining" that involves using metal-accumulating plants to leech stuff out of the soil that's later processed. (Here's more information on phytomining [in the context of gold phytomining](http://www.livescience.com/28676-plants-grow-gold.html), and here's a Wikipedia list of hyperaccumulating plants: [list of hyperaccumulators](http://en.wikipedia.org/wiki/List_of_hyperaccumulators). Quickly scanning that list, I see mostly water plants and some temperate grasses with the notable exception of creosote bush, which is very hardy desert plant.) Hyperaccumulators tend to do really well in the presence of heavy metals because of their stellar ability to sequester the stuff in their leaves and resist its toxic effects. Throw in a bit of ambient magic, and this would be the way to go for the "metal plant" effect you want--though less "steel cactus" and more "copper creosote bush".
The neat thing about this is that your desert-dwellers could exploit these hyperaccumulators to make their own metal trade easier. Creosote, for example, happens to hyperaccumulate only copper, so planting a bunch near a mixed ore sand obviates the need to refine it to get the copper out. Just let the creosote do it and collect later. I could see them gradually developing a science of phytomining by observing what plants grow well next to which ore sands, and what kind of metal can be reclaimed from those plants when they're processed. (This is something you may also want to bring in the magic for, since processing metals out of plants in the real world involves some very strong, very nasty chemical processes.)
As for the animals, well--there's magic in the setting, so the sky's the limit on what you want to do with that. Keep in mind, though, that if an animal--through ambient magic--adapts to live out in this extreme environment where it picks up all kinds of trace metals in its food, it's probably also going to adapt to make that metal *do* something for it. Deposition in bone is the most likely initial start, since that's where heavy metals already bioaccumulate in vertebrate animals, but it will spread out from there. People who are exposed to a lot of silver in their diet, for example, eventually [change color](http://en.wikipedia.org/wiki/Argyria) as it gets into their skin! (And there's another potential economic opportunity--if the metals that get into the local fauna deposit in their skin, fur, scales, or shells and result in attractive coloration that's long-lasting after the animal dies, you've got some really pretty exotic animal parts you can sell to supplement all the ore you're shipping out.)
You would not, however, get much in the way of non-magical, non-plant-life in this environment that was any bigger than bacteria. That doesn't mean, though, that you can't go pore over some lists of desert fauna and base some magical animals on them. Personally, I'd think tortoises would do pretty well if they could magically resist heavy metal poisoning and incorporate all that metal they're picking up into their shells.
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Basically you wouldn't really have flora in the ore sands, any more than you have significant amounts of plant life on sand dunes. What life there is would cluster around oases: either rivers & streams flowing down from mountains, or underground water sources.
As mentioned, that life would probably suffer from all sorts of heavy metal poisoning. You could, however, suppose that this life has evolved from extremophile microorganisms. As such it would likely be toxic to 'normal' life, and vice-versa.
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[Question]
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In a hypothetical near-future setting, humanity has been subjugated by an upper class of cyborgs. A melding of man and machine, they rule the world with an iron fist. The resistance has one chance to assassinate the supreme leader of the cyborgs, but the only weapon that will fit into the plan is a Mk 14 EBR. (it is the weapon most often employed by the rooftop snipers of the regime, who the assassin will imitate.)
Given modern science (plus anything that could be plausibly extrapolated from modern science), what can be loaded into a [7.62×51mm NATO](https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO) projectile for maximum lethality? (Up to and including overkill or splash damage. Adjacent targets will be other ranking members of the regime, getting them too is a bonus.)
Assume:
* Everything that modern science has to offer currently or can offer
within 10 years.
* No Antimatter
* Radius of the bullet's effect cannot be greater than the effective range of a normal 7.62 chambered rifle. (1000 yards at maximum)
* Money is no object.
* Information is sketchy on what parts of the target are enhanced. Assume the round needs to penetrate both flesh and titanium plate.
[Answer]
There are 3 main things you can use to increase the deadliness of a bullet:
1. Increase the damage it inflicts on impact;
2. Add a secondary effect that gives extra lethality;
3. Increase how many you can fire in a given timespan.
# Maximum damage:
Damage can be increased by 3 things:
1. Increase the speed at which it flies. The main problem with that is that the faster the bullet goes, the more likely it is to just punch a hole in the target, which actually reduces the deadliness.
2. Increase the mass of the bullet. This has the same issue as increasing the speed, with the added factor that it will also slow the bullet down.
3. Make the bullet increase in size on impact. This is the infamous hollow-tip bullet, which is designed to desintegrate on impact and shred the muscles and vital organs of the target. This is banned in international warfare by the Hague convention of 1899.
# Secondary effect:
again, 3 options:
1. incendiary ammunition. Either it puts the target on fire, inflicting secondary burns, or it explodes on impact. the main problem is that a 7.62 round has very limited space for a payload. to compare: the round itself weighs only 10 grammes of solid metal (140 grains). There are explosives and incendiaries that work on that small scale, but most of them require a special detonation device since they're impact resistant. The upside is that explosives, for the same weight, are vastly more effective at handing over energy. 1 gramme of TNT gives 25% more energy than an entire 7.62 round fired from a Barrett does.
2. toxic ammunition. This introduces a viral, bacterial or chemical payload to the target which can rapidly affect the health of the victim. The main problems here are A) ensuring intact delivery of the payload and B) preventing collateral damage when dealing with contagious payloads.
3. Radioactive ammunition. Ammunition containing small amounts of radioactive material are already in use, primarily as anti-tank weaponry.
# More Dakka:
1. More barrels. weapons like Gattling guns and the ITM Model 3 (which already fires 7.62 rounds) have multiple barrels and can fire more bullets at once.
2. Faster trigger mechanism. advances in trigger mechanisms could allow guns to fire bullets at an even higher speed.
3. no barrel. There are currently experimental weapons that have a rotating disk design that can fire spherical bullets at extreme rates. However, these aren't 7.62 rounds anymore.
# Multiple targets:
The above methods are aimed at increasing the killing power for a single target. A special design could allow the round to ricochet, hitting multiple targets. This does mean there's a higher chance at collateral.
# Accuracy:
The main problem with weapons supporting the 7.62 round is that they aren't extremely accurate. If you fire at a target that's over a few hundred yards away, chances are some bullets won't hit them. A weapon with automatic aim adjustments based on the shot before can increase accuracy. You could even develop a system that can adjust the trajectory of a bullet in-flight, allowing for more accurate shots.
# Ditching the bullet:
At a certain speed, it doesn't matter whether what you fire is a 7.62 round or a piece of licorice shaped like a 7.62 round. In fact, you could come up with a weapon that can fire anything. As with the barrelless weapon, this is not a 7.62 round anymore.
# Final thoughts:
Keep in mind that our current society has a preference to avoid "dirty" warfare. We rather don't want our projectiles to kill targets other than the one we want, and we don't want our weapons to cause prolonged death struggles. We also don't want our ammunition to deal damage AFTER it hit the target. That's why things like cluster ammunition is banned.
[Answer]
Assuming that we need maximum lethality on an armoured target, with collateral damage being considered highly desirable, the most logical ammunition is a [long-rod penetrator](https://en.wikipedia.org/wiki/Kinetic_energy_penetrator). So, we base this ammunition around a 5x~45mm uranium needle (so as to fit inside the 51mm length of the ammunition without fouling on the cartridge's base & primer) with a non-discarding finned jacket filled with 4g of [Polonium-210](https://en.wikipedia.org/wiki/Polonium#Biology_and_toxicity) powder, functionally an [APCR/HVAP](https://en.wikipedia.org/wiki/Shell_(projectile)#Armour-piercing.2C_composite_rigid) projectile. We fill the 7x51mm NATO brass with a [HNIW](https://en.wikipedia.org/wiki/Hexanitrohexaazaisowurtzitane)-based propellant in order to achieve the maximum muzzle velocity.
We fire this ammunition from a weapon that looks like the required Mk 14 EBR, though we modify the rifle to have a much stronger barrel and to be smoothbore, since long fin-stabilised ammunition [is faster and more damaging when not spin-stabilised](https://en.wikipedia.org/wiki/Armour-piercing_fin-stabilized_discarding-sabot#History). We load the brass to the point where mechanical failure of the weapon is possible after a single magazine of these rounds are fired, in order to achieve the maximum muzzle velocity, assuming that the shooter is sufficiently protected against mechanical failure of the weapon, or is a suicide agent.
So, we have several avenues of lethality. We have a cartridge loaded to produce very high muzzle velocities, at the cost of effectively destroying the rifle within a single magazine-worth of shots. We have a jacket filled with Polonium dust, that will be stripped off the depleted-uranium penetrator on impact and will burst, filling the air around the victim with several grams of Polonium-210 dust, which has an [LD50](https://en.wikipedia.org/wiki/Median_lethal_dose) of .089 micrograms The depleted uranium penetrator carries most of the kinetic energy on into the victim, passing through any practical thickness of titanium armour (if any) and most likely disintegrating since uranium is brittle, delivering the remainder of the kinetic energy to the target's vulnerable organic or electronic vitals.
So, we have a cartridge that can literally kill millions, mainly from the Polonium-210, assuming that the Polonium disperses widely enough, and considering that the Polonium is concentrated in a relatively small area, we can assume that - provided the Cyborg leader's fellow regime members breathe - they will die within days, having received a lethal dose of radiation within minutes of inhaling the stuff.
A standard 7.62 NATO M61 AP round can penetrate about 13mm of steel armour at its muzzle velocity of about 840 m/s, and at 2000 m/s, the armour penetration capability of a ~45mm depleted uranium flechette would be much higher, and using [Newton's Impact Depth approximation](https://en.wikipedia.org/wiki/Impact_depth), Depth ~= Length x (Projectile Density/Armour Density), potentially penetrating up to 112mm of steel armour, or 190mm of Titanium.
It is most likely not practical to armour a human-seeming or even a human*oid* cyborg with Titanium to a degree that this ammunition would not be able to penetrate, and even if the projectile does not kill the target outright, the Polonium-210 most likely will.
[Answer]
Given modern science I think there is plenty that could be done, the issue being how cost effective would it be? I think experimental rounds might venture into replacing the bullet with various types of explosives. Russia had developed fulminating musket balls that were designed to take out powder kegs or other strategic targets. This development led specifically to the "[Saint Petersburg Declaration of 1868](http://en.wikipedia.org/wiki/Saint_Petersburg_Declaration_of_1868)" which bans the use of explosive and fulminating ammunition weighing at or under 400 grams.
The treaty only really covered "small arms" mainly rifles and pistols larger weapons like artillery are basically exempted from the treaty due to the size of the ammunition they fire.
My next example is based on the 25mm grenade launcher the [XM25](http://en.wikipedia.org/wiki/XM25_CDTE) which has a range setting function that allows the grenade to explode (air burst) at a preset range dealing damage to targets behind walls, in trenches, or behind hills. I imagine that with some further technological advancements (and miniaturization) this type of technology could easily find its way into bullets instead of small grenades.
[Answer]
You could build a small [flux-compression generator](https://en.wikipedia.org/wiki/Explosively_pumped_flux_compression_generator) into a bullet, possibly replacing the explosive charge with simply the impact force. That would give you the combined effect of an hollow or explosive round with an electromagnetic pulse which I imagine would be quite good against cyborgs.
[Answer]
The payload can be a ricin-laced projectile (like in the historic KGB killing in Oslo(?) where an umbrella tip was used for delivery of a minuscule metal sphere). There is no cure. You need enough penetrating power to deliver the payload reliably.
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[Question]
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So, I've read a few posts on this community about medieval airships. What I have seen is so far that, how none of them mentioned about a lifting gas. Lifting gases are hard to get by.
Hydrogen and helium are extremely hard to produce/obtain and require technology that is way past medieval levels, and furthermore, they escape their containers.
Steam as a lifting gas is extremely inefficient as it requires constant heating and a lot of fuel, which is bulky and heavy.
Hot air: same problems as steam.
So, after hopping on the internet searching for information, I found out that Methane has a substantially lower density than air (0.657 kg/m3). After all, methane can easily be obtained by scrubbing biogas from animal excreta, both of which can be done with medieval levels. And it doesn't leak out of containers like hydrogen or helium. True, it may be flammable, but it cannot leak out of paper or silk, easy-to-produce hull materials in medieval levels. So this idea got into my mind.
**What are the pros/cons of using methane as a lifting gas for medieval airships**
Technology: Equivalent to Imperial China (Late Qing/Ming Dynasty)
Do give me your opinions.
EDIT:
So many people have a few misconcenptions about this question.
* Paper/silk may have been a pain in the a\*\* to produce in medieval times, but if you compare it to materials like aluminium, it's relatively "easy" to produce paper/silk. Aluminium in pre-electrolysis times was so nightmarishly difficult to produce, that Romans even regarded it as being even more valuable than gold. And don't even get me started on plastic. I mean, I get it, it's a pain in the a\*\* to make a giant zeppelin with a paper hull/silk hull, but well, consider making it out of aluminium, which is a nightmarish task, and plastic, well.... We all know plastic originated in the 1900s, far above "medieval".
* Many people seem to be confused by what "medieval technology" as it encompasses a broad range of civilizations. However, in the context of this question, the technological level is roughly similar to what the late Imperial Chinese had, roughly somewhere in the late 1700- early 1800s Qing dynasty era.
[Answer]
## Feasibility Study
**Does it have the needed lift.**
As a lifting gas, methane is close to 50% as useful as Helium. Since volume is proportional to the cube of diameter, what this means is practice is that you need a sphere 26% larger in diameter to provide the same lift using methane as a sphere using helium. It's not quite that good because you also have more weight to lift because of the additional materials needed for the larger container.
**Can you obtain the needed methane**
Forget trying to collect swamp gas - this natural source of methane will be very dilute and impossible to collect and concentrate. But there is a possible method that might be a practical method for obtaining the gas you need in quantity and purity. Make your own methane using animal waste - this is relatively low tech. Search for articles for DIY methane gas generator to get an idea of the complexity required. Many of these are not a problem to be considered feasible for low-tech implementation - with the possible exception of the gas handling (air-tight containers in particular). I would argue its close enough to be feasible basis for a story.
The bacterial breakdown of manure yields primarily methane and carbon dioxide. This is also the same process that occurs in the formation of swamp gas. Removing the CO2 would be necessary for a relatively pure methane source.
Because of the interest in climate change, CO2 removal for air is of considerable interest, but the interest in removal of CO2 from methane has been keen for some time too because the commercial value methane gas uncontaminated by CO2 (and hydrogen sulfide) - both of which are common contaminants is natural gas sources. But none of these processes are really feasible without some modern tech.
For the on-farm use of biogas, the CO2 is not a problem because even though impure the biogas will still burn readily.
Perhaps with enough control over the manure and bacteria used you can generate you gas that is pure enough to still be an effective lifting gas - at least for the purpose of your story. Consider that when most people think of the composition of farts they think of methane, even though flatus is far from pure CH4.
**Can you use it for flight**
I could easily justify this in a low-tech story by use of silk - and perhaps a low-tech but unspecified secret process of threating the silk for term-term gas retention. But, as you mentioned, others have discussed low-tech flight - so I focused on the methane specifics as methane is less of a low-tech problem than other lifting gases.
**So, as a scientific answer, I would say no - not really feasible for low-tech. But, as a story element I would say close enough to pass the sniff test.**
---
Human flatus is limited to about 10% methane at most. Hydrogen is more likely to be the primary flammable component.
Biological methane production is due to methanogens, of which all known members are Archaea, which are not classified as bacteria any more and considered separate from the plant and animal domains.
[Answer]
## A Tethered Aero-Wagon
Sure, methane does indeed float and can be used in aerostats. And, sure, your feudal baron can build methane-collection devices above every manure-pile.
So physics says "yes, it's *possible*"
However, you cannot use it as a classical *airship*: You have no useful method of propulsion nor navigation. The size you need to lift much cargo means it has a huge sail area. The structural materials are too heavy. The first errant breeze will sweep it into the air and then smash it into a pasture.
You can, however, **use it as the aerial equivalent of a wagon**. Have a team of oxen on the ground drag the hovering-just-off-the-ground tethered balloon behind them. The balloon is about the size of a hot-air balloon, and carries about one-half tonne of cargo. Or perhaps 5-6 passengers.
Your aero-wagon can traverse rough terrain since it has no wheels. It can be ferried across rivers by boat or sea-oxen (your world has sea-oxen, right?). It's small enough to be sheltered in (rather oversized) barns. It's cheaper than digging canals.
The aero-wagon can get snagged on trees, so the King might need do a bit of woodcutting along the roads. It will tend to vane in the wind, so anchoring and sitting out bad weather may be common. Places where wind is common (like mountains and seacoasts) will be inhospitable to aero-wagons, or they might need multiple teams of oxen and short tethers. Or perhaps your world has more predictable winds than ours. Rain might make the aero-wagon too heavy to get off the ground...or perhaps your world has an effective method of waterproofing the envelope.
[Answer]
I discuss some of the problems with making medieval balloons, and point out that it would be almost impossible to build diribible airships in medieval times without extraterrestrial or time traveler technology. But I do suggest a few possible uses for non dirigible balloons in a medieval society.
You say about methane:
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> True, it may be flammable, but it cannot leak out of paper or silk, easy-to-produce hull materials in medieval levels. So this idea got into my mind.
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Are paper and silk easy to produce materials at medieval levels of technology?
Part One: Paper.
In ancient times, the paper equivlents used the the Mediterranian region were papyrus from Egypt and parchment, prepared animal skins, which was better but more expensive than papyrus. And I think that in early 20th century airships the gasbags were made of many, many pieces of animal skin sewn together.
Paper was invented in China. Cai Lun (c. 50-62 AD to 121 AD), an imperial eunuch official, is tradionally credited with perfecting papermaking.
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> He is traditionally regarded as the inventor of paper and the modern papermaking process. Although early forms of paper had existed since the 3rd century BCE, he occupies a pivotal place in the history of paper due to his addition of pulp via tree bark and hemp ends, which resulted in the large-scale manufacture and worldwide spread of paper.
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Cai's improvements to paper-making are considered to have had an enormous impact on human history, and of those who created China's Four Great Inventions—the compass, gunpowder, papermaking and printing—Cai is the only inventor whose name is known. Although in China he is revered in ancestor worship, deified as the god of papermaking, and appears in Chinese folklore, he is mostly unknown outside of East Asia. His hometown in Leiyang remains an active center of paper production.
<https://en.wikipedia.org/wiki/Cai_Lun>
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> Paper was used in Central Asia by the 8th century but its origin is not clear. According to the 11th century Persian historian, Al-Thaʽālibī, Chinese prisoners captured at the Battle of Talas in 751 introduced paper manufacturing to Samarkand.[28][29] However there are no contemporary Arab sources for this battle. A Chinese prisoner, Du Huan, who later returned to China reported weavers, painters, goldsmiths, and silversmiths among the prisoners taken, but no papermakers. According to Al-Nadim, a writer in Baghdad during the 10th century, Chinese craftsmen made paper in Khorasan:[30]
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> Then there is the Khurasani paper made of flax, which some say appeared in the days of the Umayyads, while others say it was during the Abbasid regime. Some say that it was an ancient product and others say that it is recent. It is stated that craftsmen from China made it in Khurasan in the form of Chinese paper.[30]
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<https://en.wikipedia.org/wiki/History_of_paper#Islamic_world>
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> The oldest known paper document in Europe is the Mozarab Missal of Silos from the 11th century,[66] probably using paper made in the Islamic part of the Iberian Peninsula. They used hemp and linen rags as a source of fiber. The first recorded paper mill in the Iberian Peninsula was in Xàtiva in 1056.[67][68] Papermaking reached Europe as early as 1085 in Toledo and was firmly established in Xàtiva, Spain by 1150. During the 13th century mills were established in Amalfi, Fabriano, and Treviso, Italy, and other Italian towns by 1340. Papermaking then spread further northwards, with evidence of paper being made in Troyes, France by 1348, in Holland sometime around 1340–1350, and in Nuremberg, Germany by 1390 in a mill set up by Ulman Stromer.[69] This was just about the time when the woodcut printmaking technique was transferred from fabric to paper in the old master print and popular prints. There was a paper mill in Switzerland by 1432 and the first mill in England was set up by John Tate around 1490 near Hertford,[70][71] but the first commercially successful paper mill in Britain did not occur before 1588 when John Spilman set up a mill near Dartford in Kent.[72] During this time, paper making spread to Austria by 1469,[73] to Poland by 1491, to Russia by 1576, to the Netherlands by 1586, to Denmark by 1596, and to Sweden by 1612.[33]
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<https://en.wikipedia.org/wiki/History_of_paper#Paper_in_Europe>
I am not certain whether the "medieval" in the question refers to medieval China, medieval India, medieval Islamic society, or medieval Europe, but all those societies had paper making before the end of the middle ages.
And I wonder how cheap or expensive paper was in those medieval societies and how large the usual sheets of paper were, and how large they could have been made with medieval technology.
Even a tiny size hot air balloon would require an air bag at least 100 by 100 feet or meters, and thus a total area of 10,000 square feet or meters. And I doubt whether an airbag that large could have been made in a single piece of paper.
And I have to wonder if medieval glue or medieval thread could hold together a paper airbag made of of tens, hundreds, or thousands of pieces. And of course if someone is considered physiclaly weak the cliche is to say "he couldn't fight his way out of a paper bag". I can imagine airship disasters caused by giant paper airbags ripping apart from the stress of supporting the weight of the gondola.
Part two: Silk.
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> Several kinds of wild silk, produced by caterpillars other than the mulberry silkworm, have been known and spun in China, South Asia, and Europe since ancient times, e.g. the production of Eri silk in Assam, India. However, the scale of production was always far smaller than for cultivated silks. There are several reasons for this: first, they differ from the domesticated varieties in colour and texture and are therefore less uniform; second, cocoons gathered in the wild have usually had the pupa emerge from them before being discovered so the silk thread that makes up the cocoon has been torn into shorter lengths; and third, many wild cocoons are covered in a mineral layer that prevents attempts to reel from them long strands of silk.[4](https://en.wikipedia.org/wiki/Silk#China) Thus, the only way to obtain silk suitable for spinning into textiles in areas where commercial silks are not cultivated was by tedious and labor-intensive carding.
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<https://en.wikipedia.org/wiki/Silk#Wild_silk>
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> Silk use in fabric was first developed in ancient China.[12](https://en.wikipedia.org/wiki/Observation_balloon) The earliest evidence for silk is the presence of the silk protein fibroin in soil samples from two tombs at the neolithic site Jiahu in Henan, which date back about 8,500 years.[14](https://en.wikipedia.org/wiki/USS_Los_Angeles_(ZR-3)#/media/File:Zr3nearvertical.jpg) The earliest surviving example of silk fabric dates from about 3630 BC, and was used as the wrapping for the body of a child at a Yangshao culture site in Qingtaicun near Xingyang, Henan.[12](https://en.wikipedia.org/wiki/Air-supported_structure)
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> Legend gives credit for developing silk to a Chinese empress, Leizu (Hsi-Ling-Shih, Lei-Tzu). Silks were originally reserved for the Emperors of China for their own use and gifts to others, but spread gradually through Chinese culture and trade both geographically and socially, and then to many regions of Asia. Because of its texture and lustre, silk rapidly became a popular luxury fabric in the many areas accessible to Chinese merchants. Silk was in great demand, and became a staple of pre-industrial international trade. Silk was also used as a surface for writing, especially during the Warring States period (475-221 BCE). The fabric was light, it survived the damp climate of the Yangtze region, absorbed ink well, and provided a white background for the text.[17] In July 2007, archaeologists discovered intricately woven and dyed silk textiles in a tomb in Jiangxi province, dated to the Eastern Zhou dynasty roughly 2,500 years ago.[18] Although historians have suspected a long history of a formative textile industry in ancient China, this find of silk textiles employing "complicated techniques" of weaving and dyeing provides direct evidence for silks dating before the Mawangdui-discovery and other silks dating to the Han dynasty (202 BC – 220 AD).[18]
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> Silk is described in a chapter of the Fan Shengzhi shu from the Western Han (202 BC – 9 AD). There is a surviving calendar for silk production in an Eastern Han (25–220 AD) document. The two other known works on silk from the Han period are lost.[8](https://en.wikipedia.org/wiki/Henri_Giffard) The first evidence of the long distance silk trade is the finding of silk in the hair of an Egyptian mummy of the 21st dynasty, c.1070 BC.[19] The silk trade reached as far as the Indian subcontinent, the Middle East, Europe, and North Africa. This trade was so extensive that the major set of trade routes between Europe and Asia came to be known as the Silk Road.
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> The Emperors of China strove to keep knowledge of sericulture secret to maintain the Chinese monopoly. Nonetheless, sericulture reached Korea with technological aid from China around 200 BC,[20] the ancient Kingdom of Khotan by AD 50,[21] and India by AD 140.[22]
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<https://en.wikipedia.org/wiki/Silk#China>
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> In the Odyssey, 19.233, when Odysseus, while pretending to be someone else, is questioned by Penelope about her husband's clothing, he says that he wore a shirt "gleaming like the skin of a dried onion" (varies with translations, literal translation here)[33] which could refer to the lustrous quality of silk fabric. Aristotle wrote of Coa vestis, a wild silk textile from Kos. Sea silk from certain large sea shells was also valued. The Roman Empire knew of and traded in silk, and Chinese silk was the most highly priced luxury good imported by them.[23] During the reign of emperor Tiberius, sumptuary laws were passed that forbade men from wearing silk garments, but these proved ineffectual.[34] The Historia Augusta mentions that the third-century emperor Elagabalus was the first Roman to wear garments of pure silk, whereas it had been customary to wear fabrics of silk/cotton or silk/linen blends.[35] Despite the popularity of silk, the secret of silk-making only reached Europe around AD 550, via the Byzantine Empire. Contemporary accounts state that monks working for the emperor Justinian I smuggled silkworm eggs to Constantinople from China inside hollow canes.[36] All top-quality looms and weavers were located inside the Great Palace complex in Constantinople, and the cloth produced was used in imperial robes or in diplomacy, as gifts to foreign dignitaries. The remainder was sold at very high prices.
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<https://en.wikipedia.org/wiki/Silk#Ancient_Mediterranean>
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> Italy was the most important producer of silk during the Medieval age. The first center to introduce silk production to Italy was the city of Catanzaro during the 11th century in the region of Calabria. The silk of Catanzaro supplied almost all of Europe and was sold in a large market fair in the port of Reggio Calabria, to Spanish, Venetian, Genovese, and Dutch merchants. Catanzaro became the lace capital of the world with a large silkworm breeding facility that produced all the laces and linens used in the Vatican. The city was world-famous for its fine fabrication of silks, velvets, damasks, and brocades.[37]
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> Another notable center was the Italian city-state of Lucca which largely financed itself through silk-production and silk-trading, beginning in the 12th century. Other Italian cities involved in silk production were Genoa, Venice, and Florence. The Piedmont area of Northern Italy became a major silk producing area when water-powered silk throwing machines were developed.[38]
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> The Silk Exchange in Valencia from the 15th century—where previously in 1348 also perxal (percale) was traded as some kind of silk—illustrates the power and wealth of one of the great Mediterranean mercantile cities.[39][40]
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<https://en.wikipedia.org/wiki/Silk#Medieval_and_modern_Europe>
So by the late middle ages silk making had spread from China to large parts of Asia, northern Africa, and to southern Europe. And I have wonder how much silk was produced and how expensive it was, since only a minority of people in those areas wore silk garments.
Part Thrre: Paper and/or silk for balloons?
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> At the time of their invention hot air balloons were usually made of silk, which is wonderfully suited to the purpose. Unfortunately, it is also prohibitively expensive and extremely difficult to repair. Modern hot air balloon fabrics have replaced silk with lighter and stronger options. Most hot air balloons are made of nylon now. Tyvek is sometimes used with experimental balloons, but its flammability makes it unsuitable for most purposes.
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[https://nvaloft.com/2013/02/26/what-are-hot-air-balloons-made-of/#:~:text=At%20the%20time%20of%20their,with%20lighter%20and%20stronger%20options.](https://nvaloft.com/2013/02/26/what-are-hot-air-balloons-made-of/#:%7E:text=At%20the%20time%20of%20their,with%20lighter%20and%20stronger%20options.)
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> On November 21, 1783 the first free flight carrying a human occurred in Paris, France in a hot air balloon made of paper and silk made by the Montgolfier brothers.
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The first public demonstartion of a hot air balloon was by the Montgolfier brothers in 1783.
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> To make a public demonstration and to claim its invention the brothers constructed a globe-shaped balloon of sackcloth tightened with three thin layers of paper inside. The envelope could contain nearly 790 m³ (28,000 cubic feet) of air and weighed 225 kg (500 lb). It was constructed of four pieces (the dome and three lateral bands) and held together by 1,800 buttons. A reinforcing fish net of cord covered the outside of the envelope.
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> On 4 June 1783, they flew the balloon at Annonay in front of a group of dignitaries from the états ″particuliers″. The flight covered 2 km (1.2 mi), lasted 10 minutes, and had an estimated altitude of 1,600–2,000 m (5,200–6,600 ft). Word of their success quickly reached Paris. Étienne went to the capital to make further demonstrations and to solidify the brothers' claim to the invention of flight. Joseph, given his unkempt appearance and shyness, remained with the family. Étienne was the epitome of sober virtues ... modest in clothes and manner...[9](https://en.wikipedia.org/wiki/Silk#Ancient_Mediterranean)
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So some early balloons combined paper and silk, probably in an attempt to combine the good qualities of each material.
Parth Four: A Hydrogen filled Medieval Balloon?
I note that the first hydrogen filled balloon was launched shortly afterwards, on August 27, 1783.
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> Charles conceived the idea that hydrogen would be a suitable lifting agent for balloons having studied the work of Robert Boyle's Boyle's Law which was published 100 years earlier in 1662, and of his contemporaries Henry Cavendish, Joseph Black and Tiberius Cavallo.[3](https://en.wikipedia.org/wiki/History_of_paper#Paper_in_Europe) He designed the craft and then worked in conjunction with the Robert brothers, Anne-Jean and Nicolas-Louis, to build it in their workshop at the Place des Victoires in Paris.[4](https://en.wikipedia.org/wiki/Silk#China) The brothers invented the methodology for the lightweight, airtight gas bag by dissolving rubber in a solution of turpentine and varnished the sheets of silk that were stitched together to make the main envelope. They used alternate strips of red and white silk, but the discolouration of the varnishing/rubberising process left a red and yellow result.[3](https://en.wikipedia.org/wiki/History_of_paper#Paper_in_Europe)
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<https://en.wikipedia.org/wiki/Jacques_Charles>
So as early as 1783 balloons of silk, without paper, were built, using a coating on the silk in an attempt to make it airtight.
Charles and the Robert brothers bullt the first attempt at a dirigible balloon which flew on July 15, 1784, but the propulsion method didn't work.
How was the hydrogen for the first hydrogen balloon produced?
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> It was filled with hydrogen that had been made by pouring nearly a quarter of a tonne of sulphuric acid onto a half a tonne of scrap iron.[9](https://en.wikipedia.org/wiki/Silk#Ancient_Mediterranean) The hydrogen gas was fed into the balloon via lead pipes; but as it was not passed through cold water, great difficulty was experienced in filling the balloon completely (the gas was hot when produced, but as it cooled in the balloon, it contracted).
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<https://en.wikipedia.org/wiki/Jacques_Charles>
I note that 18th century chemistry had only comparatively recently evolved from medieval alchemy.
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> Sulfuric acid was called "oil of vitriol" by medieval European alchemists because it was prepared by roasting "green vitriol" (iron(II) sulfate) in an iron retort. The first vague allusions to it appear in the works of Vincent of Beauvais, in the Compositum de Compositis ascribed to Saint Albertus Magnus, and in pseudo-Geber's Summa perfectionis (all thirteenth century AD).[38]
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> In the seventeenth century, the German-Dutch chemist Johann Glauber prepared sulfuric acid by burning sulfur together with saltpeter (potassium nitrate, KNO3), in the presence of steam. As saltpeter decomposes, it oxidizes the sulfur to SO3, which combines with water to produce sulfuric acid. In 1736, Joshua Ward, a London pharmacist, used this method to begin the first large-scale production of sulfuric acid.
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<https://en.wikipedia.org/wiki/Sulfuric_acid#History>
So it seems to me that a medieval society with a more advanced alchemy/chemstry might be able to produce sulpheric acid and hydrogen for hydrogen balloons.
Part Five: Dirigibles?
A dirigible is a dirigible balloon. Dirigible means capable of being steered, guided, or directed. As I wrote above, Charles and the Robert brothers attempted to built the first dirigible balloon in 1784, following the proposals of Jean-Baptist Meusnier.
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> Meusnier is sometimes portrayed as the inventor of the dirigible, because of an uncompleted project he conceived in 1784, not long after the first balloon flights of the Montgolfiers, and presented to the French Academy of Sciences. This concerned an elliptical balloon (ballonet) 84 metres long, with a capacity of 1,700 cubic metres, powered by three propellers driven by 80 men. The basket, in the form of a boat, was suspended from the canopy on a system of three ropes.
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> In 1852, sixty six years after Charles and the Robert brothers 'oar powered' dirigible, Henri Giffard's design for the first successful powered airship was inspired by Meusnier's ideas.[5](https://en.wikipedia.org/wiki/Silk#Wild_silk)
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<https://en.wikipedia.org/wiki/Jean_Baptiste_Meusnier>
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> On 24 September 1852, Giffard made the first powered and controlled flight travelling 27 km from Paris to Élancourt.[3](https://en.wikipedia.org/wiki/History_of_paper#Paper_in_Europe) The wind was too strong to allow him to make way against it, so he was unable to return to the start.[3](https://en.wikipedia.org/wiki/History_of_paper#Paper_in_Europe) However, he was able to make turns and circles,[citation needed] proving that a powered airship could be steered and controlled.[4](https://en.wikipedia.org/wiki/Silk#China)
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<https://en.wikipedia.org/wiki/Henri_Giffard>
So Gifford's flight showed that a dirigible powered by a steam engine was possible.
But it was not until internal compustion engines could produce more power than steam engines while having less weight than steam engines, that either airplanes or dirigibles becme practical. The first practical dirigible was probably the first Zeppelin in 1900.
So I find it a little hard to believe in medieval airships using hot air, hydrogen, methane, or any other lifting gas, whithout a strong low weight power source such as would not be developed until centuries after the middle ages.
Part Six: Uses For (Possibly Methane Filled) Balloons in the Middle Ages.
If powered flight would be a very improbable use for balloons, methane filled or otherwise, without a power source which would be very improbable to develop in the middle ages, what could balloons be used for?
1. user535733 suggested tethered aero wagons pulled by oxen on the ground.
2. tethered balloons were used for military observation purposes in the US Civil War for 1861-1865 and as early as the French Revolutionary War.
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> The first military use of observation balloons was by the French Aerostatic Corps during the French Revolutionary Wars, the very first time during the Battle of Fleurus (1794).[1](https://en.wikipedia.org/wiki/Cai_Lun) The oldest preserved observation balloon, L'Intrépide, is on display in a Vienna museum. They were also used by both sides during the American Civil War (1861–65)[2](https://en.wikipedia.org/wiki/History_of_paper#Islamic_world) and continued in use during the Franco-Prussian War (1870–71).[3](https://en.wikipedia.org/wiki/History_of_paper#Paper_in_Europe) Balloons were first deployed by the British Army's Royal Engineers during the expeditions to Bechuanaland in 1884 and Suakin in 1885.[4](https://en.wikipedia.org/wiki/Silk#China) They were also deployed during the Second Boer War (1899–1902), where they were used in artillery observation at the Battle of Magersfontein and during the Siege of Ladysmith.[5](https://en.wikipedia.org/wiki/Silk#Wild_silk) In South America, a reconnaissance balloon was deployed by Brazil in July 1867 during the Paraguayan War.[9](https://en.wikipedia.org/wiki/Silk#Ancient_Mediterranean)
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<https://en.wikipedia.org/wiki/Observation_balloon>
3. Other military uses?
Johann Muller von Konigsburg, or Regiomontanus (1436-1475), was a German scholar. Legend says he made mechanical flying animals, an eagle which flew to great a visiting emperor, and a tiny fly exhibited indoors. This has inspired the famous comment about the wonders of minituarization: "Who admireth not the fly of Regiomontanus more than his eagle".
I have read a suggestion that his flying eagle could have simply been a kite. And that reminds that I read something about some sort of aerial devices, some shaped like eagls (one or two headed?) used by German armies in the early modern era. Those flying devices might have been kites or powered by gunpowder rockets, like the somewhat later rockets of Mysore and Congreave.
What military purpose would those aerial devices have? If they were propelled by gunpowder rockets they could strike someone and explode. And if they simply flew above an army they might intimidate the opposing army.
And you may remember the Macy's Thanksgiving Day Parades in NYC with giant balloons shaped like all kinds of fictional characters carried along the streets. So possibly in a medieval society vast balloons shaped like dragons or other monsters could be made and floated above and army to scare members of opposing armies.
4. Architecture?
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> A gas holder or gasholder, also known as a gasometer, is a large container in which natural gas or town gas is stored near atmospheric pressure at ambient temperatures. The volume of the container follows the quantity of stored gas, with pressure coming from the weight of a movable cap. Typical volumes for large gas holders are about 50,000 cubic metres (1,800,000 cu ft), with 60-metre (200 ft) diameter structures.
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<https://en.wikipedia.org/wiki/Gas_holder>
I note that methane is a major component of natural gas which is stored in gas holders.
Many gas holders have a gas tank surrounded by a frame work of girders. Such a framework could enclose a balloon full of methane, for example.
I have seen pictures of balloons with all sorts of custom made shapes,including buildings. And of course a building shaped balloon would have to be tied down to keep from floating away instead of exerting weight upon its foundations.
Here is a link <https://en.wikipedia.org/wiki/USS_Los_Angeles_(ZR-3)#/media/File:Zr3nearvertical.jpg> to a photo of the 658 foot 4 inch long airship USS *Los Angeles* tied to a 200foot tall mooring tower on August 25, 1927. In this terrifying photo, a sudden gus tof wind has pushed the *Los Angeles* almost vertical.
Suppose that the outer girder framework of a gasometer was built as tall as an airship was long, and a vertical airship was built and inflated inside the framework and tied to the framework. If the weight of the framework and the lift of the airshop inside were almost identical, the frame with an attached airship inside might possibly be constructed to heights of hundreds or thousands of feet or meters without becoming too heavy to to stand.
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> An air-supported (or air-inflated) structure is any building that derives its structural integrity from the use of internal pressurized air to inflate a pliable material (i.e. structural fabric) envelope, so that air is the main support of the structure, and where access is via airlocks.
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<https://en.wikipedia.org/wiki/Air-supported_structure>
And obviously a pressurized building couldn't have been made in medieval times.
But people could build a vast hall with walls and no roof. And if they could build a large balloon with the dimensions of the hall, they could float it over the walls and attach it to the walls as a roof over the hall. Thus large balloons could be built to look like vast domed roofs when seen from the outside.
So hypothetical medieval balloons could have had hypothetical uses in medieval architecture.
5. One Way Transportation?
If there is a place with winds with fairly steady direction and speed, balloons could be launched from that place in the direction of the prevailing winds. Presumably when they reached open fields or lakes near the destination community they could be deflated to land, and folded up for eventual transport back to where they came from, while the passengers have much shorter trip to their destination than if went htewhole way on land.
Possibly the place of launching could be some sort of observation point, and messages sent by balloons would usually reach headquarters much sooner messages sent on horseback.
Conclusion:
Even though it would be highly difficult to make powered dirigible airships in medieval times without technology from aliens or time travelers, other uses for balloons can be imagined.
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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).
[](https://i.stack.imgur.com/3tOT3.jpg)
Sea serpents appear in various mythologies. Mesopotamians have Tiamat, Greeks have Hydras,Jews have Leviathan, the Norse have Jormungandr.What they all have in common are that there these giant snake-like creatures under the sea that can easily capsize contemporary ships.
Sea Snakes are real life animals but Sea Snakes aren't any larger than land snakes. Is it biologically possible for a whale-sized snake to evolve?
[Answer]
May I present the Oar Fish
[](https://i.stack.imgur.com/dZeSJ.jpg)
[](https://i.stack.imgur.com/ayTMv.jpg)
[](https://i.stack.imgur.com/qoW6A.jpg)
I don't know much about them, but [HERE](https://en.wikipedia.org/wiki/Oarfish) is the wikipedia link to the most real sea serpent I have ever heard of.
[Answer]
# Make them warm blooded
The titanboa, the largest known snake, offers a look into what would be needed to make bigger snakes. It existed in a considerably warmer climate, but it's going to be hard to get that in an ocean.
The first thing, therefore, is a higher metabolic rate. Snakes are cold blooded, and limited in growth by this - I'd imagine there's a limit to how large a snake a cold blooded metabolism could support - at a point, the relatively sluggish digestive system would be a limiting factor
So, making them warm blooded would remove this limit, and, as such, the size limitation - no reason a sea snake can't be as large as a whale shark in this case.
It's obviously not the only limit, but I'd imagine it's a big part of the problem - a warm blooded sea serpent is going to be able to chase down prey, and move faster when it comes to capsizing boats, too. A warm blooded metabolism is also cheaper to maintain the larger the creature gets - the square/cube law working in our favour, for once!
I can't see any other reasons that sea snakes couldn't evolve to enormous size - there's no limits on their internal organs being crushed by their own bulk, or of having to develop massively stronger skeletons.
[Answer]
Having something similar to a sea snake evolve to fill the same niche as baleen whales do on earth can explain the size and shape. sea snake's anguilliform swimming style is extremley efficient(source: <https://journals.biologists.com/jeb/article/208/7/1329/16002/Eel-migration-to-the-Sargasso-remarkably-high>). Assuming sea serpents wouldn't have any predators, they might keep getting longer throughout their whole life as lengthening their body means they can push off of more water at once. Territoriality could explain their tendency to attack ships, though I don't know what could cause them to be territorial.
[Answer]
**There were some very large sea snakes, and snake relatives, far back in Earth's history**
Snakes from the family Palaeophiidae, specifically the genus *Palaeophis* may have reached up to 12 meters long. They were around from the Late Cretaceous (the last age of dinosaurs) until the Eocene. The world was much warmer throughout this entire time, and the beginning of the Eocene in particular was the warmest time since the Dinosaurs. Some argue that these snakes were warm-blooded.
<https://en.wikipedia.org/wiki/Palaeophis>
In addition the Mosasaurs, marine reptiles from the Cretaceous, are thought to have been more closely related to snakes than any other group of animal! They could reach whale size (13 meters and 5.5 tons). It is also thought that they were warm blooded. You can count them as sea-serpents if you like, but they had fins. Then again early sea-snakes also had some fins (Pachyrachis and Haasiophis) also probably had fins (or at least limbs).
To answer your question, yes. Very large "sea-serpents" can and have evolved.
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[Question]
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Scribes and other literate administrators were a hot commodity in the ancient world. Whether they were Confucian Scholar-Gentry or Catholic Monks, the pre printing press world made whole social classes defined by literacy. Likewise, harems and other large retinues of wives and concubines were a common occurrence in the ancient world, whether they be in Ancient China, Ancient Egypt or the Ottoman Empire; rulers maintained these women for social, dynastic, diplomatic and hedonistic reasons at considerable expense. These women were not exactly working in the fields or grinding grain.
Given these two real world precedents, my setting features an emperor in a pre printing press society using his extensive royal harem as a bureaucratic and scribal organization, as their physical needs are already maintained by slaves and that he wants administrators whom he can be sure will be loyal
Is this plausible? Or would training noblewomen in literacy and giving them administrative tasks be a disaster in the making?
[Answer]
**I don't think you need historical precedents to validate your scenario.**
Since there is nothing inherently problematic about training women as scribes or in other bureaucratic functions, this would be completely up to the emperor, who has, in all likelihood (but depending on your specific scenario), supreme power, and he won't need to justify this action to anyone else.
This function of his harem could remain undisclosed to the public, necessitating even less justification.
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That being said, there certainly are precedents (which might be emphasized in historical sources exactly because of their singularity):
* In the Ottoman Empire:
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> "***The Imperial Harem was one of the most important powers of the Ottoman court**. It was ruled by the Valide Sultan. On occasion, the Valide Sultan would become involved in state politics. For a time, the women of the Harem effectively controlled the state in what was termed the "Sultanate of Women"*".
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> [source](https://en.wikipedia.org/wiki/Ottoman_Empire#Government)
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Or in a more general sense:
* In the Roman Empire:
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> "***Women could be scribes and secretaries**, including "girls trained for beautiful writing," that is, calligraphers.*"
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> [source](https://en.wikipedia.org/wiki/Women_in_ancient_Rome#In_business)
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[Answer]
The answer to this question depends upon the nature of harems. The female occupants of harems were typically not free. Whether they were slaves or the daughters of the nobility, the nature of harems is that their occupants are typically not free to leave, whether permanently or temporarily, and neither were they typically admitted to the harem voluntarily.
I have no doubt that whatever the origin of the women in a harem, they would be quite capable and probably quite willing to serve as scribes, if only to relieve the boredom of being isolated from society.
However, the fact that the women in the harem are not free should give any wise ruler pause. History has shown that harem women are quite capable of ambition for themselves and/or their offspring, whether they originated as slaves or the daughters of the nobility. They are similarly capable of resentment for their loss of freedom. These two facts alone would mean that no matter how eagerly or reluctantly a harem woman agrees to act as a scribe or an administrator, their work cannot be trusted. Additionally, the longer the custom of using harem women as scribes and administrators goes on, the greater the chance that not only may their work be compromised by their loyalties or lack thereof, but also that the security of the secrets passing through the harem may be compromised.
I have no doubt that some harem women may be perfectly loyal, capable, enthusiastic and trustworthy administrators and scribes, however they may very well be living side by side with women who are merely pretending to possess those virtues for their own ends or the ends of those who arranged for them to enter the harem.
If the owner of a harem is concerned with 'idle hands making the devil's work' (a major problem with harems historically), there are better things for the women of the harem to do than to be exposed to the functions of government. Things such as art, which may be profitable and fulfilling yet unlikely to be able to compromise the functioning of the government.
On the other hand, if the occupants of the harem are volunteers (and weren't volunteer*ed*), who compete for entry into the harem, and who have the freedom to leave temporarily or permanently, and are paid for their labours, their trustworthiness would be little more in doubt than that of any other bureaucrat.
[Answer]
Archeologists have found the remains of a [medieval woman with blue teeth](https://www.nytimes.com/2019/01/09/science/10-archaeology-teeth-painting.html), and they think its due to her being a writer.
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> several years ago, when studying the dental plaque of a nun from medieval Germany, Dr. Radini saw something entirely new: particles of a brilliant blue. She showed the findings to Christina Warinner, another tartar expert, who was shocked.
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> The particles, it turned out, were of ultramarine pigment, the finest and most expensive of blue colorings, made of lapis lazuli stone from Afghanistan. The German nun with the pigment in her teeth — B78, as she is known in the archaeological literature — was likely a painter and scribe of religious texts. And she must have been highly skilled to have been entrusted with such a rare powder, the researchers said.
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Considering that in those times a lot of the clergy came from nobility, and that apparently having women trained in writing didn't let hell loose, I guess the answer to your question is that it is plausible.
[Answer]
**Good idea - although you wouldn't want to give too much power to Bureaucratic Corps**
As it was mentioned in other answers, women could have been very active in ancient and medieval politics. They could upstage and even murder their husbands. Classic harem held moderate amount of power - most of it was coming from its connection to the monarch. If, in addition to that, you want to make it a "Bureaucratic Corps" - in effect, giving it full executive power, it may become too powerful even for a monarch to handle.
There need to be checks and balances to make sure your country is not run by this harem and monarch is not just a consort (although this idea may be very interesting).
One limiting factor can be that no noblewomen should be eligible for harem. Women should have no connections with outside powers, and there should be no split loyalties.
Another idea is merit - you want your bureaucratic corps competent, and this means that women's brains should mean more than their looks. I can imagine holding "Imperial Examinations" in which girls compete in their knowledge, and the high prize is joining the Imperial Harem.
Merit is even more important within the harem. In traditional harem, women with best looks and best craftiness would hold the highest positions. This is not what we want in bureaucratic corps. So the monarch should have a little say in who is his most favorite wife - this should be determined by a maximally impartial process.
[Answer]
In history, there were queens more decisive and proactive than the king himself.
* Nur Jahan queen of Mughal emperor Jahangir.
* Elizabeth Woodville Queen of King Edward IV.
Queens, if well educated and well trained, could become better rulers than the king alone.
[Answer]
There's a slightly ambiguity in this question. A harem is the section of a household where men are not allowed (apart from children, eunuchs, etc), but the question seems to refer to the pop culture definition of harem, meaning only the wives, concubines and potential concubines. Both can work, but in wildly different setups.
In the first scenario, these bureaucrats are simply regular female bureaucrats. It has the advantage over regular bureaucrats as these women will not be allowed to have families of their own and thus a little less nepotism. This way, every place where they need a bureaucratic office, they make a small palace, castrate a few guards and "invite" a few educated women to join. This setup is not even that hard to justify, I think, its basically a female-only monastic order where instead of God they serve the Emperor. Theoretically the Emperor might sleep with them, not because it is a position requirement, but just because he is the f\*ing Emperor.
The second is a bit tricky. First of all, a kingdom needs way more bureaucrats than the emperor can sleep with, thus only the highest offices could possibly be handled by the imperial harem. Second, harems had a lot of power even without these offices, not because the women in them could boss people around, but they had privileged contact to the guy who could boss people around. In other words, this scenario is just historical harems on steroids (apart from the women actually getting titles and recognition). As such, this comes with all the problems of historical harems, on steroids as well: women fighting each other for power, influence and to make their sons the next emperor; poisoning competent princes to further your dumb kid claim; political instability that comes from the fact that the imperial policies might be decided based on who's the Emperor's favorite (this one is not caused by the harem). Overall, great for drama, terrible for governance, but 100% believable and almost historical.
The two scenarios are not mutually exclusive. The back bone of the bureaucracy could be the monastic order type, while the high offices the harem type. Note as well that if the order membership start from a early age (little girls sent by their families) and the women of the harem are drawn from these monastic orders, the whole system becomes stable due to social conditioning.
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[Question]
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I am irritatingly perfectionist and must know things to relax my anxiety.
So this creature here. From the top its head shape is salamander. Its mouth is large and strong and the cranium needs enough space for sentient brain and good fitting hats. It can switch to quadruped movement.
It is approximately 4 feet tall.
It will need to be able to not fall forward on its face from either stance. Not too top heavy. Would balance be an issue? I'd rather not give it a counter balance tail. Its body is roughly barrel shaped, so more thick support neck could fit. I'm unsure about the limb joint positioning, as I notice the quadruped shoulder and enlarged chest looks a bit weird on a biped (don't worry about the limb shape; those extra lines in the front are just for telling me its leg position as quadruped). The back legs are animal shaped and around the same length as its body plus halfway up the neck. Its hands and feet are like chicken feet.
Will these proportions work strength and balance wise? What might I need to change?
I hope you can see the images okay. I don't like to put down harder to erase lines until I'm very sure that's where they need to be.
[](https://i.stack.imgur.com/2CBBr.jpg)
[](https://i.stack.imgur.com/X4hyh.jpg)
I did a bit of change. The neck is a bit longer and thinner, if that makes it more realistic. The neck bones are positioned something like this. Im attempting to copy a chimp like head to neck connection for switching between biped and quadruped position.
[](https://i.stack.imgur.com/rRBHX.jpg)
Though now I'm concerned about if the brain case is too small in proportion or if it having the generally large head already makes up for it.
Am I allowed a side question? I need to know how stretchy a spine can be.
Potential head/neck fixes?
[](https://i.stack.imgur.com/Ng1hJ.jpg)
Maybe a slightly shorter head would make it more believable. His head is big and wide enough that it should make up for the shorter head height, for brain space. Hopefully the hat will still stay on okay. I could probably shorten it even more if I weren't worried about the hat falling off. (Hat base shown here) How do the spinous processes look? Do they look like they are enough and proper? I don't know much about those.
[](https://i.stack.imgur.com/t5QZD.jpg)
Perhaps s neck.
[](https://i.stack.imgur.com/BCqj5.jpg)
[Answer]
I would say that it is perfectly feasible.
**1.** If we consider [dwarfism in humans](https://www.pinterest.co.uk/pin/796644621569232616/), it is frequently the case that the head appears proportionally larger than average with respect to the body. Yet such people can successfully take part in sports without overbalancing.
[](https://i.stack.imgur.com/JAoR0.png)
**2.** You mention salamanders and it is true that for example giant salamanders have large heads in proportion to their bodies. Of course a normal salamander does not stand upright but evolution could surely make this happen.
[](https://i.stack.imgur.com/fQaTC.png)
**3.** You would do well to consider the phenomenon of [neoteny](https://www.thefreedictionary.com/neoteny)
Young humans (who have relatively large heads) are capable of walking and running at an early age. If the species retained the childish shape longer then this would work perfectly well for someone 4ft tall. By retaining the general body-shape of a two to five year old into adulthood but with larger muscle growth, and better co-ordination through experience, your creature could be perfectly well balanced.
[](https://i.stack.imgur.com/4Q2bm.png)
**4.** Finally, here is a [video of 5-year-olds racing](https://youtu.be/_4K3gbYBtX0)
[](https://i.stack.imgur.com/Ej00j.jpg)
[Answer]
Your main problem is you want a variable stance but have drawn a perfectly upright neck. To work quadrupedally the neck articulate should be as horizontal as possible, for an up right stance it should be as vertical as possible. Animals like chimps and gorilla that do both use a compromise with something close to a 45 degree angle. Basically the angle of spine should match the angle of the neck to skull joint, if two drastically different spinal postures are uses you compromise between the two. A side effect of this is the neck posture is not optimal in either position, when upright it gets swung forward, so the whole head sits forward relative to the body, when horizontal it sits with a with a strong upward curve.
[](https://i.stack.imgur.com/5qCXH.png)
[](https://i.stack.imgur.com/L7uOD.png)
when horizontal, aka quadrupedal, it sits with a with a strong upward curve of the neck to bring the eyes forward. If your creature has equally long limbs this will be even stronger.
[](https://i.stack.imgur.com/jr974.jpg)
You will also notice that doing this requires a much stronger neck, which is why the neural spines of the neck vertebrae are very tall, they need a lot of space to attach muscle to hold the head in these positions. This is even more true for your creature because the head is huge, bigger even than a human. This means the neck has to sit further forward than you have drawn to have enough room, which means pushing the head even further forward or giving it a humpback.
Here look a bear head when upright.
[](https://i.stack.imgur.com/mFvhZ.png)
Notice how far forward the head sits, because the neck connects to the skull right in the back of the skull like most quadrupeds, the whole head projects forward. they can pull the head further back, but only because the neck is long enough to bend in an S curve. You can see a less extreme version in this ape, which has a neck articulation in the middle between quadrupedal and upright.
[](https://i.stack.imgur.com/7Pwlf.jpg)
You can see it in this troop of chimps:
[](https://i.stack.imgur.com/gj3sT.png)
Again notice how far forward the head is in the upright position, most of the skull is forward of the chest.
I really do recommend taking some time to study animal anatomy if you want to draw fictional animals.
Neck range of motion on humans:
[](https://i.stack.imgur.com/VH6P5.png)
[Answer]
Head size isn't what strikes me as unfeasible here. It's how you think the spine meets the cranium.
[](https://i.stack.imgur.com/1zvJa.jpg)
Anatomically, the body plan and head shape / orientation you've chosen is great for a bipedal creature: when standing, its eyes face forward. The trade-off is that the base of skull rests on top of the spine like a capital on a pillar.
In order for you to keep the ability to quadripedambulate, you'd need a long saurian neck, or else bend this poor fellow's neck 90deg at the upper thorax.
[Answer]
While the structure is sound, if you want your creature to be able to both walk bipedally and quadipedally, you would probably need the creature's vertebrae to be individually shorter, creating more joints where it can bend its neck to be able to see properly in both stances.
[Answer]
i believe it is width and depth wise, however intelligence tends to be proportional to head to body ratio within animals. Take this into consideration as height-wise, it may prove insufficient for more intelligent species.
[Answer]
...Have you seen Erythrosuchus?
[](https://i.stack.imgur.com/STfDK.jpg)
Your creature is fine.
(Wikipedia article on the Erythosuchids: <https://en.wikipedia.org/wiki/Erythrosuchidae>)
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[Question]
[
In one of my stories, there are people with powers. Inherited from parent to child or through accident and experimentation. There's the main government like ours, and a para-military agency organisation that is involved with dealing with unusual events, objects and people, such as gifted people.
( A bit of background is this, Gifted people aren't yet common but they do happen so this agency deals with them by indexes any and all gifted people once found and released with monitoring about their use of abilities. Including the use in self-defence. The normal government doesn't really know or deal with this themselves due to the reliance on the Agency until there's a public exposure problem in the event of a crime or accident.
Gifted people aren't common enough that they don't have a method of justice in the normal human legal system when facing a public trial and being gifted can easily put the person at a disadvantage with human prejudice of being able to do something a human cannot and risks that come with abilities. More often than not, they're sent to the agency for imprisonment since that 'assures' the human government the threat is appropriately dealt with. Again, more background information on background issues. )
**However**, there's a community of gifted people that do live away from humans. Which is what I'm curious in exploring more than the human vs gifted.
Now, what I'm looking for is trying to create a justice system that's been developed by powered people for powered people. A majority of the community are isolated in culture but there are the ones that join this community, like my MC. But as this is a different culture, ways of the justice system would have differences to our justice system.
But I remain uncertain on what I'd need to consider in terms of building on in terms of the laws and codes of justice. Powers are good, yet there would still be things to be considered;
* **Moral implications and ethics** in use of abilities, such as transferring the mind of a person with a terminal illness into the body of another that is otherwise brain-dead. Grey areas of abilities can be hard to fit into a standard code of systems.
* **Damage** of the property and/or people if the use of power is uncontrolled or in a fight, etc,
* **Conduct** of those with potentially intrusive abilities (mind-reading, x-ray vision, etc)
I know that there'd no doubt been a long list of powers that'd have a chapter in the system to maintain the community.
**What would I need to consider with what I've got so far to build a functional justice system?** or Would I just expand on what I've got into finer details?
[Answer]
**No one super who is drastically more powerful than anyone else**
The way human society tends to "work" is that people are mostly safe because physically humans beings are more or less equal within a margin of error. Yes, some people are stronger than others, but in a straight-up fight stripped of followers and political power even the most brutal warlord is still human. Even the strongest person will still likely lose against a gang formed by the second, third, and fourth strongest. Even if you bring up differences in strength between men and women, those differences are in the sense of "on average". Women can still kill men if they have the element of surprise, have weapons, are more skilled fighters, are just bigger, etc.
What this means is that every individual in society has to be on their best behavior, because if they aren't the rest of society will gang up on them and take them down if they start negatively impacting the group. Introduce superpowers, however, and now you have a system where one person (like some super-psychic or flying brick) can set themselves up as leader through brute force and nobody can do anything about it. Reminds me of the saying in Greek myth where Zeus tells the other Olympians "I'm in charge because I'm the strongest, even if the rest of you all teamed up on me at once you could not bring me down" [paraphrased].
Human legal systems are mostly based on the concept of isonomy "all individuals are essentially equal [by which I mean talents like intellect or physical stature are negligable], and therefore shall be treated as equal under the law". Except now you have a situtation where this is blatantly not true. Not only do you have a situation where people are *not* equal under the law (normals versus supers), but you have individuals that even if you wanted to you cannot force to comply. Who is going to successfully arrest Superman if he breaks the law? So with that, you devolve into a society of barbarism with just one rule: don't make the super-gods mad. Society becomes intrisically based around what you and what you can do rather than who you are when you introduce variable superpowers (and people without) into the mix.
Incidentally, this is a lot of the reason why Superman makes a lot of people antsy despite being a big blue boyscout (which we'll hereafter call the "Lex Luthor argument"). Superman technically doesn't need humanity in any direct way. He doesn't rely on other people for food, or shelter, or resources. When he needs to pay taxes on the Fortress of Solitude he just crushes coal into diamonds. An army of normals couldn't stop him. An army of superheroes debatably couldn't stop him, unless you were very careful who you picked (i.e., other flying bricks) or very sneaky (read: Kryptonite). Humanity has no way to put a check on his power. There is nothing to stop him from setting himself up as a god-king through physical force beyond his own conscience. And most human beings aren't as virtuous as Superman (and there's the whole, "Clark Kent likes being normal" aspect, but that's neither here nor there).
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## Treat Super Powers Like Gun Ownership
The US legal system already pretty much addresses this problem in the form of "aggravated" and "reckless endangerment" crimes.
To dissuade the use of deadly weapons, the sentencing for any crime becomes more severe anywhere a weapon is involved in the execution of the crime, even if it is not used to harm anyone. If you rob a store with your bare hands, it is robbery, but if you use a gun to do it, it is aggravated robbery. Using super powers to rob a store creates the same sort of unfair, traumatizing, and increasingly dangerous sort of power dynamic as a gun; so, when a super does use their powers in a crime, the punishment is elevated which would hopefully be enough to convince at least some would be criminal supers to commit crimes using their mundane abilities as much as possible.
On the same token, carrying a gun is not illegal, getting into a fight with a gun on your person is not an aggravated crime, shooting a gun in a safe environment not illegal, and being a super is not illegal. Supers are allowed have powers and use them in ways that common sense would tell you are safe and legal, but using your powers recklessly (like firing a gun blindly into the air) is a crime unto itself. This leaves the subject of using one's powers somewhere along the vein of, if you are not sure it is safe, you can get in trouble for it.
There may also be certain zero tolerance zones, like gun free zones, where using powers is entirely forbidden.
The advantage of treating all powers like gun ownership is that you don't criminalize anyone for having one power or another, you only criminalize its misuse. Using mind control to steal a car is still grand theft auto, but now it is aggravated grand theft auto. Using super strength to crush a person's skull is still murder, but now it's aggravated murder. Creating a situation that blinds drivers is reckless endangerment whether you do it by throwing eggs at their windshields or by conjuring up a smoke screen. The definition of crimes are all about what you are doing instead of what powers you are using to do it; so, you can keep your code of laws relatively fair and simple.
As a bonus, this approach to super power law would be pretty consistent with normal people law such that it would work even outside of their own special culture.
*Side note: in some countries, people with unordinary physical abilities like formal martial arts training can be prosecuted for aggravated assault even without a weapon. In a since, these jurisdictions already handle "super powers" this way.*
## Addressing your specific concerns
**Moral implications:** Legal systems are about ethics, not morality. The general rule of law is that that which is not illegal is legal until it is not, and any moral implications beyond that is not for the courts to decide. Transferring the mind of a person with a terminal illness into the body of another that is otherwise brain-dead is perfectly legal as long as you can prove you are not killing either person in the process under the current definitions of murder. If it does kill one of the people, then you would need to petition legislatures to define this action as an exception to the law. If it's not illegal, but congress sees it as a "form of murder" then it could be made illegal.
Also, most US states also use precedent in the evaluation of the law to stand in for congressional decisions until the law can be refined. So, the first time someone decides to press charges for something ambiguous like this, it could be decided very quickly if it is considered murder or not by the first court case that evaluates it. Then everyone knows if that strange thing is or is not murder moving forward.
**Excessive Damage to Property:** Damage to property laws should suffice. The plaintiff brings you to court, damages are assessed, and you are required to pay restitution, and if the damages exceed a certain amount or your ability to repay them, then there can be felony charges that stack which could result in jail time.
**Conduct of those with potentially intrusive abilities:** Laws concerning fraud and coercion are generally left intentionally vague because people are so creative when it comes to finding new ways to do them. Fraud is defined as any intentional deception or misrepresentation used to benefit yourself or someone else, and coercion covers any use of threats, commands, and any use of force. So, if you can implant false memories or impulses directly into someone's mind, that is clearly Fraud. If you tell a person to jump off a bridge and they do, that is coercion. So, without modifying the law at all, most of the more insidious intrusive abilities are already covered.
As for simple mind reading, there are no laws to prevent it, but there are many laws to prevent the use of said knowledge. You can steal someone's PPI sure, but using it to take their money is theft, using it to get into their digital accounts is hacking, and using it create accounts in their names is identity theft, using it to ruin a person's reputation is defamation, using it to manipulate them is blackmail, so on and so forth.
If you really want to crack down on psychic intrusion, you could expand [CFAA](https://en.wikipedia.org/wiki/Computer_Fraud_and_Abuse_Act) law to cover the misuse of psychic abilities according to the same criteria that we evaluate hacking, since psychic intrusion and hacking are so similar in nature.
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## Build up from Tyranny
There are superhumans among us now. A tiny number of people, on paper, own (directly or indirectly) most everything. These could split into empires and armies clashing, suppressing, and ruling by force. Much like an overpowered superhero might.
But they don't. Why? These super humans are satisfied that concerns of great urgency to them are infrequent and can be worked out through a system. They are satisfied with roles as influencers, trend setters, deal makers, and moon shot-ers. They are satisfied that, at the moment, the benefits of arming and going to war with the world do not justify the expense to stability, mobility, safety, and peace of mind.
Similarly, your superhuman justice system would need to satisfy the people with the greatest strength that their needs can be cared for by that justice system. It means that sometimes justice might not be served, or sometimes their will be crisis between principles and the wants of one of these most mighty superhumans. But, as long as they are satisfied that what they care about is being taken care of expeditiously, it might be possible to convince them to hang up the cape and play chess, or make films, or something like that.
## Build up also from Anarchy
The public consists of very large numbers. To provide for their needs is impossible, hence the adage "you can't please all of the people all of the time".
However, a public of normal or superhumans can be satisfied with a justice system that lets them know what to expect. In this case, the decisions made should (most of the time) be easily predictable by experts on the topic. It should be easy enough that the public can deal with a lot of justice requests on their own.
Examples: a written legal code (like the Lextalionis) with descriptions of requirements and penalties for non-compliance, a well-understood system of arbitrating disputes : who makes the decisions, how disputes are presented, timeliness; a written constitution that in broad strokes outlines principles of government; a mechanism for evolving the rules and procedures (a law- or rule- making body).
The public needs to trust that most of the time, "the process" delivers results they will be happy with. If they can rest assured the system will take care of them, the public will defend it.
## Some Suggestions
**Define person** : everyone struggles with this one. From the ${3 \over 5}^{ths}$ compromise in the constitution, to tribalism, to the elderly, to criminals, the insane, the young, the very young, those on life-saving equipment, and those without "gifts". Who is entitled to full protection of "the system"? Who gets less than full protection? Who gets nothing?
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One thing you should consider is the possibility of super powers adjusting an individual's personality, and at the extreme, power-induced-psychosis or sapient/sentient powers. Let me outline a couple example cases:
* An individual develops some sort of changer-power which lets them transform into a bear or whatever. Unfortunately, when they're in bear-form, they can't keep "control" and often act far more violently than they would in human form. Even worse, the longer the individual goes without transforming, the more the "urge" to transform grows. Now, say this individual kills someone while in bear form. Are they at fault? Can they plead mental illness?
* An individual develops some sort of mover/shaker power which enables them to warp space into pocket dimensions and teleport. Unfortunately, with this power comes an extreme case of kleptomania. The individual gets physically ill if they do not regularly steal things to appease their power, and this can't be "cheesed": the individual needs to actually believe that they've stolen something to appease the power. How do you deal with this? What if it can be conclusively proven that the individual's kleptomania disappears inside a power-nullification zone?
* An individual develops an exotic "demon summoning" power and gains the ability to summon temporary "demons" which they can use to fight or whatever. Unfortunately, as a byproduct of his power, infernal creatures whisper in their head all the time and drive them to commit crimes or other nefarious deeds. Is the individual at fault? Can the demons be prosecuted in a court?
* An individual develops an extreme changer power which essentially transforms them into a ghost. While in ghost form, they can't interact with the world, eat, sleep, or even breathe. The only way to survive is if they're actively possessing someone--otherwise they suffocate if they can't hold their breath. Unfortunately, possession is very invasive and the ghost-individual instantly has full control of the victim along with instantaneous access to all their knowledge. How would a court handle something like this? Prohibiting the individual from possessing people would kill them, but at the same time, it would be very hard to fight a willing possessee without hopping through a couple unwilling bodies beforehand. Similar problems rise up with people who develop vampire-esque powers requiring them to drink blood, eat dreams, or be a cannibal to survive.
[Answer]
**Themis.**
There is a super whose power is to be the justice system. She is extremely old but not aged in appearance. She may be immortal. She has a depth of understanding beyond that of normal people and supers both and her gift is the gift of fairness. And she is blind.
Judicial matters involving supers (and sometimes those not) are brought before Justice.
---
A problem with this system is that it has all the proverbial eggs in one basket. What if Justice were not able to carry out her duties? What if she were kidnapped and held for ransom? And how would this entity Justice comport herself in such a situation?
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[
So, my werewolves are a diet version of the classical lycanthrope.
* They have considerable strength and a thick hide, but a trained human can still overpower them.
* They can be hurt with regular weapons and poisoned with silver items
(more precisely, the pathogens that reside on silver surfaces).
* They have a good sense of smell but can be stunned/irritated with strong-smelling chemicals.
* They can regenerate but it takes time.
* They don't transform, only on the first occasion when they turn into their hybrid form then stay that way.
* They are in perfect control, except for the duration of the full moon, in which case some precautions have to be made.
There are three ways one can become a werewolf:
1. A curse that strikes random people.
2. Getting bitten by a werewolf.
3. Being born as a werewolf (werewolves CAN reproduce)
Now, even purebred (born as) werewolves are almost impossible to discern from humans, as far as personalities go. Though they tend to use their Jacobson's organ more frequently.
Werewolves live in self-sufficient tribes. They have agriculture and everything but are limited in number, as the curse is fairly rare, and werewolves practice social distancing (avoid humans) during full moon, along with taking anesthetics before the event to snooze through it.
The "natural" enemies of werewolves are the monster hunters, a terrorist organization that is universally despised (even among humans) for harboring serial killers that found out membership is an easy way to evade authorities without having to give up their hobbies. The only reason this kos (kill on sight) group is able to exist is because of capitalism.
**The demand is dead werewolves and monster hunters have a monopoly over the supply; but why? Why would people want werewolves dead when they are so human-like and are frequently former humans, many of whom were in good standing?**
The society is medieval, albeit the existence of artifacts (ancient technology that helps out in small ways) makes it more similar to its romanticized (knight in shining armor, etc..) form, devoid of plagues and famine but with a strong feudal society.
The racism towards werewolves has to frame them as a dangerous element that has to be controlled and/or completely eliminated with no room for negotiation and it needs something to stand on. You sow lies from a grain of truth.
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## **ALL THE REASONS PEOPLE HATE EACH OTHER:**
* **Religion**. God has decreed those that walk on two feet but are not man are demons. Wolves often appear in sheep's clothing. This stuff was common in a world without proof of the supernatural. Real proof would magnify these forces greatly. And if one religion says werewolves are good, another says they're evil to differentiate themselves.
* **Culture**. Werewolves practice different traditions, possibly religions, maybe have a secret language, eat different foods.
* **Racism**. All by itself, people are primed to hate and fear those who are unlike themselves - and that is among full humans. In a medieval society, this is even worse. If you have no experience with outsiders, they all seem foreign. Can you honestly say as a modern human, you could walk into a village of werewolves alone and feel comfortable? Magnify that feeling ten times.
* **Fear of the unknown**. People in this time simply didn't know any better. If you were lucky, the village priest might have some education. If not... How do you know lycanthropy doesn't spread by contact, or that the folks in the werewolf village don't plan to kill and eat you all? Are you taking the word of the werewolf?
* **Greed**. The werewolf village has stuff we want and craftsmen who've made nice stuff. I'd sure like it. Look at all that land in the hands of those no good, mangy (a real possibility) varmints. And those bounty hunters aren't doing this for fun - they don't get paid if you don't hate your neighbors.
* **Revenge**. Sure, Billy was in our village and is now a werewolf. We love Billy, but he's the walking dead now, saying he's fine, but we know better. They took him, and who's to say you're not next?
* **History**. Hundreds of years of stories say the werewolves were evil in grandpa's day, and you respect your elders, don't you? A war happened once, and your people learned how to kill those werewolves. You know Grandpa has a haunted look when he talks about it - they were so strong and terrible. But now you're prepared and have the numbers to set things right.
* **Outright lies and superstition**. (somewhat covered already) Did you know crossing a werewolf's path causes your chickens to stop laying, and cows dry up because a werewolf came in the night and suckled.
* **Evil werewolves**. They aren't better than people, and people can be really awful. All these biases can apply in the reverse direction. Maybe a certain percentage of werewolves are really vile sapients with no regard for human life. That's enough on it's own.
* **Random conflicts**. Perhaps dogs recognize werewolves as wolves and freak out when they're around. Maybe Billy who lived in the village is having trouble adjusting to his new life and wanders back to get drunk over and over, boasting and smacking people around. A village maiden says a werewolf raped her to explain how she got pregnant.
* **Envy**. Life isn't perfect, but it sounds like it's good to be a werewolf. Who doesn't want to be stronger, tougher, to have better smell, etc.? People either want to become werewolves, betraying traditional values, or they feel cheated by them. My eldest son ran off to become one, then came back and wanted his inheritance. The nerve! The werewolves wouldn't let me become one, just because I killed a few people. I'll show them!
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There can be many reasons, from a religious belief that they are sons and daughters of the devil to a genuine concern over creatures that can loose control and kill a person in a full moon.
Though I'm mostly sure that they're feared and unwanted **specifically because they're so hard to tell apart from normal humans**, so we have creatures that can look human, but then at one moment they can go feral and maul you if you're not prepared, and what's worse, it could be anyone, even someone that looked normal and was in good standing. "Remember of Markus, the innocent boy who we thought couldn't hurt a fly? Turns out he was a werewolf, and it seems like he was the one who killed Mary". Tales of people who were attacked by supposed friends who were actually werewolves during the night, true or not, would be more than enough to create not only a feeling of hatred towards this undercover threat, but also a sense of distrust. Small communities would be even more closed, travelers and strangers would be heavily suspected on and seen as unwanted, and accusing someone of being a werewolf could potentially be a sentence of death by angry mob.
I also don't doubt that this terrorist faction would make use of this already present sense of unease to raid certain homes during the night, especially during the full moon, and then blame the werewolves, showing everyone how vicious these beasts are, how good it is for them to be around and why it's so important to keep paying protection fees, so that they can remain geared up in order to make the world a better place by hunting these monsters to extinction. Like good old capitalism, there'll usually be people exploiting a potential source of income, even if it means becoming something that'd make a feral werewolf look like a civilized person.
[Answer]
>
> They are in perfect control, except for the duration of the full moon,
> in which case some precautions have to be made.
>
>
>
If this is the case you honestly don't need anything else. You have a group of people who are physically stronger than baseline humans *and* for a significant portion of the year become uncontrollable monsters that can't be reasoned with. **You don't need to spin lies about werewolves stealing babies or controlling the banks if all the propaganda about werewolves being violent, uncontrollable monsters is actually true at least 10% of the year (approximately the number of full moon nights in a year).**
You've basically created a perfect storm where conflict between the groups is almost unavoidable:
* If the werewolves were physically stronger than humans but were in control of themselves at all times (basically akin to depictions of lizardfolk, giants, etc. in fantasy), there would be no problem and humans and werewolves could coexist. Werewolves would be seen as no less threatening than someone who is large and muscular. And while there are people who are terrified of anyone who is larger than them (I would post examples but I don't want to get in trouble), those people are also rightly ridiculed as being overly paranoid.
* If the werewolves were identical to humans but just went nuts at the full moon, there would be much less problems. People can mostly handle another human who has gone nuts and has lost the most dangerous thing about humanity: our brain. An individual who is significantly larger, stronger, and more durable than humans, cannot be easily restrained by most people (a trained individual might be able to, but those individual will by definition be rare), and cannot be reasoned with is a serious danger to those around them.
* If the werewolves just became animalistic but not savage during the full moon, they easily could be coexisted with. Most animals aren't violent monsters, and if you encountered a werewolf [that acted like a real wolf during the full moon the werewolf would just run away](https://www.youtube.com/watch?v=r76GJDP0uWQ). But given we're talking about werewolves I'm assuming standard werewolf rules apply, which means savagery at full moon. I also get that standard werewolf rules imply that they shred anything that isn't a werewolf at the full moon, but in reality if the werewolves lose control they should be shredding each other as much as the humans.
* I don't know what the setting of your world is, but this would not be the case of "humans bad". Every sapient species with the ability of forethought would recognize the werewolves as a threat so long as they can't control themselves on the full moon.
You might say "well it's not their fault, they suffer from a condition outside of their control". We have that IRL too, with people who suffer from severe psychosis or other mental disabilities. Those people are invariably either locked up in mental institutions or prisons. In ye old days before people had even a smidgen of empathy for those they considered strange they would have been *shot*. And while the vast, vast majority of people with mental health problems or disabilities are not a threat to anyone (indeed they are more likely to be the victims of abuse), people are still going to paint them with the same brush. Best case scenario is you'd have werewolves locked up in mass institutions and studied to attempt to "cure" them (or at least remove the moon psychosis), because werewolves represent a real threat to public safety. They probably wouldn't be allowed to breed (either by biting people or making more werewolves the natural way), either indirectly because they're all locked up or directly because humans consider it unethical to bring a new life into this world to suffer the way they perceive the werewolves' as having suffered. The only people who would care about establishing a society where werewolves could exist without changing werewolf behavior are the werewolves.
People honestly don't care about ethics when their own safety is at risk. Look at how the U.S., who are normally hyper-paranoid about government tyranny and would normally be up in arms if someone tried to take their rights, just sat back and watched as the government interned Japanese-American civilians during World War II. Note that this is not strictly due to racial divides making people think the internment was "not our problem", either, the U.S. interned a bunch of first-generation German-Americans during the war and [considered interning *everyone* of German and Italian ancestry](https://en.wikipedia.org/wiki/Internment_of_German_Americans#World_War_II), only to realize that so many Americans had German or Italian ancestry that they would have to imprison half the country). If safety is on the line people will throw their own brother under the bus real fast.
[Answer]
**Revenge of the great dead king!**
You see, these werewolves were not always hated, in fact, they were our friends and equals. Then something happened, something terrible.
This truth is not known to many people and only exist as a mere rumor, Once there was a great king, loved by all, in whose rule, werewolves were treated equal to humans and worked alongside us. The king had 3 sons, and the youngest was the greedy one who despised these terrible monsters and wanted the kingdom for himself which was to be soon given to the eldest prince.
So, he devised a plan to get what he wanted, on the night of the full moon, he tricked some werewolves guards and servants into king's quarter, killed the king and his two brothers making it look like it was done by the werewolves and then killed the werewolves too.
After that a panic and hatred towards werewolves spread throughout the nation, the greedy brother took over the kingdom and ordered the killing of these terrible monsters throughout the nation, they had no choice left, but to run and hide.
Hundreds of years later, even today, people hold their grudge towards these werewolves, monster hunters take advantage of this grudge, as some people came to know about this story/rumor they made peace, but old grudges die hard, Hence the enmity continues.
[Answer]
They stole my pigs!
Or I thought it was them. I think so. And I'm 100% sure that it was MY pig. The bottom line is:
**Carthago delenda est** errr I mean Werewolves must be stopped.
You have an organisation that not only profit from hunting but also harbour psycho- and sociopaths. They have double reason to hunt. First is money, second *"As long as we are useful we are free"*. So they would steal a chicken or two from some village, came around two days later and says "Oh, did someone stolen your poultry? Must be those weres. Today it's chicken, tomorrow it will be you".
And then they go on their merry way of raping young men, bulling girls and courting cows. But you can't say anything because they WILL help you with werevolwes.
Because after their visit not a single chicken went missing.
They might be bad but are not as bad as the Turned ones. I heard, that when you woo the moon you pillage, eat 100 mens meals in one night, defy the king, don't pay taxes and throw paper on the street. Not to mention you roll your eyes on your mother!
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[Question]
[
I'm working on a species of fantasy creature based off the mythological Behemoth. It's only constraint is the laws of physics itself. Environment and evolutionary lineage won't be relevant due to the species' place in the story. It's a vertebrate land animal, and I want it to be larger than any land creature that's ever existed, but there's a problem:
The largest terrestrial animal known to history is the Argentinasaurus, which by some estimates weighed up to 100 tons. (Meanwhile, Elephants weight around just 6). Some have said this is the absolute size limit for terrestrial land animals.
If so, what changes would need to be made to make an organism's design exceed that mass? Like, 200-500 tons? So far the major issues with gigantism in vertebrate species I've found include-
1. Issues with bone structure, with the weight soon becoming too much for the bones to handle.
2. Too much stress on the heart and lungs
3. The strength-to-weight ratio of Muscles declining the bigger an organism is, eventually making it unable to support just it's own weight.
4. Issues with regulating body temperature.
So far, the solutions I've come up with simply involve adding more sets of hearts and lungs evenly distributed around the body and more solid bones than that of a dinosaur (which are hollow like birds) but less so than mammals.
The species I'm designing has 6 limbs, at least one set of heart and lungs for each major section of it's body, with extra limbs for support and even skeletal structures designed to reinforce certain muscles to have greater strength, like the jaws for example. The creature lives on a planet with a gravitational pull similar to earth's.
Would these be viable means of making a super-sized physics-based living organism? What else am I missing?
[Answer]
The main problem with scaling up a quadrupedal vertebrate is that beyond a certain mass, the legs simply can't be made thick enough to both support its weight and also allow it to move. Before reaching that point, it would pass through a stage where it was still able to move, but only so slowly that it would be highly vulnerable to predators.
This problem can be resolved by segmentation. By adding extra pairs of legs down the length of the body, each leg would need to support a smaller fraction of the total body mass. For quadrupedal vertebrates, the upper mass limit appears to be around 100 metric tons, which equates to 25t per leg. However, such a creature would have moved quite slowly. However, by reducing the mass per leg, and increasing musculature, a segmented Behemoth would be able to move faster. It may be possible to have a mediportal gait at up to 20 tons per segment, 10 tons per leg, though 10 tons per segment 5 tons per leg would be better.
So, we could have a Behemoth that at adult size might have 30 segments, 60 legs, and weigh over 300 metric tons.
The next problem that must be overcome is that of circulation and respiration. A single heart would suffer great stresses circulating blood around even a mostly horizontal creature, however by having a heart in each body segment, this can be overcome. Likewise, by having a set of lungs in each body segment, the creature's respiratory needs can be scaled up without having to resort to an impractically wide trachea leading to a single set of lungs.
So far, we have a creature much as described by the OP. However, some elements are still missing. The most important is that of diet. However, it does not make sense to have such a massive body and to have a diet consisting primarily of high-quality food, such as other animals or fruit. A creature such as this seems built to eat grass or even whole trees.
With a body well in excess of 100 tons, a Behemoth need not have a particularly high basal metabolism, though an elongated body plan would give a higher surface area than its mass would suggest, requiring a somewhat higher energy input to maintain its body temperature. I'm assuming that it is homeothermic, since it isn't likely to evolve to that size if it wasn't.
So, given that the Behemoth is a herbivore, it then has the problem of gathering enough food. Given that it has a narrow body in comparison to its length, a single head would limit the rate at which it could collect food. Whether grazing or browsing, there's only so much food that can be gathered in a single bite... so either that is a limiting factor, or another solution is found. As the Behemoth evolved, its mouth might widen to be able to take in more food with a single bite, but while this works with grass to a degree, it wouldn't work very well when browsing upon woody plants. The solution is to make the lips more mobile, so that different sections of the mouth can approach the Behemoth's food in different ways. Evolving this approach to its logical extreme would mean that the Behemoth would have perhaps six to eight mouths on stalks, that could independently browse or graze upon whatever plant material was available. The mouths would most likely have a broad, beak-like appearance, with horny upper and lower lips so as to be able to snip or strip off grasses or leaves. Given that it might take a bite at a tree branch, then pull back without completely biting through a branch in order to strip off the leaves, the beak might take on a serrated appearance.
Internally, the individual mouths are likely to evolve ossifications and joints to support the structures and allow a greater bite force, and as they extend beyond the head like enlarged elephantine trunks, further ossifications within their musculature would allow greater strength and extensibility.
The food ingested by these mouths would not have been masticated. The original jaws and dentition might be adequate for some pre-processing of the food, but to process bulk vegetation, a gizzard is the most effective solution. Since a gizzard relies upon rocks to provide an abrasive surface, when the rocks wear out, they can readily be replaced with others found in the environment. With a gizzard, it is reasonable to expect that the original jaws and dentition would atrophy, and the former buccal cavity would effectively be a manifold that collects food and passes it further down the digestive system to the gizzard.
A herbivore as large as a Behemoth would not have the luxury of selectiveness as to the food it eats. This, then precludes it being a foregut fermenter like a cow: ruminants are sensitive to overly-rich food, which can cause life-threatening complications. Hindgut fermentation allows the digestive system to remove excess nutrients before delivering the indigestible components to the fermentation apparatus, guaranteeing that there will be no risk of overly-rich food causing runaway bacterial growth.
The elongated body would allow plenty of room for the digestive system without having to be especially wide to accommodate the volume of the gut.
As a hindgut fermenter, without the need to be terribly selective with its food, there is a high probability that a Behemoth would be an opportunistic predator and scavenger. If an animal of the right size crossed its path so that it could simply reach out and ingest it, or if presented with the carcasse of an animal, it might take the opportunity to do a bit of predation or scavenging.
The Behemoth would most likely follow the basic vertebrate paradigm in that its brain and senses of sight, hearing, taste and smell would be centred in the head. Being a herbivore, it would have eyes on the sides of its head so as to maximise its field of view. It would have sensitive, mobile ears. It might also have an excellent sense of smell, given that it has a lot of volume in which to put the necessary sensory apparatus.
In order to defend itself from predators, a Behemoth could charge and trample, however the great length of its flanks could present a significant vulnerable area, so it seems reasonable that a Behemoth would evolve the ability to kick sideways, potentially with some variation on the theme of claws or horns on each of its feet so as to increase the potential lethality of its kick. Naturally, it would be able to bite with its multiple mouths, the jagged beaks being able to inflict serious injuries on a large opponent, or simply ingest a smaller opponent.
It might also have the ability to body-slam, though this would be more a side-effect of being able to rear up to exert more force upon a tree in order to push it over.
On the matter of reproduction, a Behemoth would likely produce relatively small offspring, if for no other reason than its narrow body would not readily allow larger offspring. However, the length of the body would allow for multiple offspring relatively easily. So, we can expect litters of relatively immature offspring in fairly large numbers.
It is unlikely that a Behemoth would be terribly intelligent. Much of its brain would likely be dedicated to controlling its complicated body, however, such an animal would not have the need for particularly great intelligence. So long as it can locate food, mates and its progeny, and lash out at anything threatening, it needs little else.
[Answer]
There were larger sauropods, but they are known only from a few bones. The current record-holders include Argentinosaurus, which may have weighed 100 tonnes.
The problem with size is the ratio between the surface area and volume of a creature increases exponentialy as it get's bigger, thus a large arachnid body would be largely unable to support it's own weight.If an animal were isometrically scaled up by a considerable amount, its relative muscular strength would be severely reduced since its mass would increase by the cube of the scaling factor. As a result of this, cardiovascular and respiratory functions would be severely burdened. For a creature that massive to exist certain environmental circumstances would have to be in place.
1. Lower gravity: Therefore the weight penalty wouldn't matter as much
2. Stronger bones/reinforcement to withstand the weight of their own mass. A structure of materials far stronger than mineralized bones, organo-metallic compounds, carbon-carbon style bones?
3. MORE oxygen in the atmosphere to fuel the metabolic requirements for large animal locomotion (This is apparent in the Carboniferious period on Earth, Arthropods were 10x the size they were average today, Scorpions the size of a dog, Dragonflies the size of a seagull
references:
1. <http://en.wikipedia.org/wiki/Square%E2%80%93cube_law>
2. <https://dinosaurpivoting.boards.net/thread/895/important-scaling>
3. <https://en.wikipedia.org/wiki/Largest_organisms#:~:text=The%20current%20record%2Dholders%20include,are%20known%20only%20from%20fragments>
[Answer]
**Social insect style: at maximum size dispense with movement.**
1: Nonambulatory. At full weight the behemoth would lie on its belly, distributing weight across a broader surface.
2: Main bulk under lungs. Expanding the lungs means lifting the back. The belly and most weight is underneath and does not need to move to breathe.
3: Nonmetabolic tissue. Most of the weight is fat, which has minimal metabolic and circulatory needs.
A question becomes feeding. The B could have a long neck and snag things passing by, but things would learn to steer clear. It would quickly eat all plants within reach. You could have a head like a flamingo and filter feed in the ocean or some other resource that renewed itself from a larger territory.
Or you could have smaller and more mobile animals bring it food, which I think is the best way.
This now converges on a queen termite - nonmotile and fed by its smaller, nonreproductive offspring. That method could work for vertebrates. The mature full sized behemoth eats and has young and that is it. Its offspring defend and feed it. Periodically the queen gives birth to more mobile dispersing forms who can leave the huge territory it needs and start their own colonies.
[Answer]
Short Answer:
So what you want is a "giant Behemoth".
[https://en.wikipedia.org/wiki/The\_Giant\_Behemoth[1]](https://en.wikipedia.org/wiki/The_Giant_Behemoth%5B1%5D)
In my long answer I discuss modifying the planet of your story, if it is not Earth, to make large creatures more probable, discuss the size records of known creatures on Earth, and discuss how to modify your creatures to make them more mammoth.
Long Answer:
Part One of Ten: Being A Pedant.
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> I'm working on a species of fantasy creature based **OFF** the mythological Behemoth
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I believe that correct grammar is to say "based **OFF OF** the mythological Behemoth" or "based **ON** the mythological Behemoth". And the second sounds better to me.
Part two of Ten: Making The Planet Suitable.
Planetary characteristics to consider include both the surface gravity and the escape velocity. The surface gravity determines how much creatures weigh and how strong their bones and muscles have to be. The escape velocity determines the planet's ability to retain an atmosphere. And of course the type of atmosphere a planet has depends on both what atmosphere it produces or acquires and its ability to retain an atmosphere.
[https://en.wikipedia.org/wiki/Surface\_gravity#:~:text=The%20surface%20gravity%2C%20g%2C%20of,including%20the%20effects%20of%20rotation.&text=Surface%20gravity%20is%20measured%20in,are%20meters%20per%20second%20squared.[2]](https://en.wikipedia.org/wiki/Surface_gravity#:%7E:text=The%20surface%20gravity%2C%20g%2C%20of,including%20the%20effects%20of%20rotation.&text=Surface%20gravity%20is%20measured%20in,are%20meters%20per%20second%20squared.%5B2%5D)
[https://en.wikipedia.org/wiki/Escape\_velocity#:~:text=In%20common%20usage%2C%20the%20initial,to%201.7%20km%2Fs](https://en.wikipedia.org/wiki/Escape_velocity#:%7E:text=In%20common%20usage%2C%20the%20initial,to%201.7%20km%2Fs)).[3]
And I have noticed that surface gravity and escape velocity do not change equally. I have noticed that for planets and other bodies in the solar system with less mass than Earth their escape velocities and surface gravity do not have the same ratio compared to Earth's escape velocity and surface gravity. The escape velocity of a smaller world will be slightly larger, relative to Earth's, than the surface gravity.
This suggests to me that a planet with less mass than Earth should be a good setting for your giant behemoths.
How much can you change the mass of your fictional planet while still having a breathable atmosphere?
You should read *Habitable planets for Man*, Stephen H. Dole, 1964, 2007, which has a section on the size range of planets habitable for humans, and thus for other large land based vertebrates.
Part Three of Ten: A highly Oblate Planet?
Another factor to consider is making your planet rotate very fast and have an oblate shape. Surface gravity will be higher at the poles and lower at lower latitudes, being the lowest at the equator, where your giant behemoths might live.
The classic example of a highly oblate planet in science fiction is Mesklin in *Mission of gravity* by Hal Clement (1953). Mesklin is very large and rotates very fast, so the surface gravity is three g at the equator and hundreds of g at the poles.
[https://en.wikipedia.org/wiki/Mesklin[4]](https://en.wikipedia.org/wiki/Mesklin%5B4%5D)
I am not sure about whether the atmosphere would have uniform density or be denser at the poles. I also wonder what the escape velocity would be at the equator of a rapidly spinning world and whether the atmosphere would escape from the equator.
Some people speculate that a large moon, like the Moon, is necessary for a planet to have large tides and since Earth life might have began in tidal zones, necessary for a planet to have life. Since the Moon has been receding and slowing down Earth's spin for billions of years before complex life appeared, an initially highly oblate planet might slow down its spin and loose most of its oblateness before it developed an oxygen rich atmosphere and large lifeforms.
But maybe advanced aliens came to a rapidly spinning new planet and terraformed it with an oxygen rich atmosphere and seeded it with advanced lifeforms from their planet, and over millions of years the giant behemoths evolved on that planet while it was still spinning rapidly.
Or maybe a large moon is not necessary for life on a planet.
Part Four: A Jinxed Planet?
Another interesting science fiction world is Jinx in Larry Niven's Known Space series.
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> Jinx, orbiting Sirius A, is a massive moon of a gas giant (called Primary), stretched by tidal forces into an egg shape and tidally locked. In the habitable areas it has high surface gravity near the limits of human extended tolerance. The points nearest to and farthest from Primary (called the "East" and "West" ends) lie elevated out of the atmosphere in vacuum. The atmosphere of the belt-region halfway between them is too dense and too hot to breathe, and is inhabited only by the Bandersnatchi. The zones between the vacuum areas and the high-density belt area have atmosphere breathable by humans. Jinx's "East" and "West" ends become a major in vacuo manufacturing area. Jinxian humans are short and squat, the strongest bipeds in Known Space. But they tend to die early, from heart and circulatory problems. There is a tourist industry which provides substantial useful interplanetary trade credits for the Bandersnatchi, who allow themselves to be hunted by humans under strict protocols.
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[https://en.wikipedia.org/wiki/Known\_Space#Locations[5]](https://en.wikipedia.org/wiki/Known_Space#Locations%5B5%5D)
So a Jinx-like world might have the right surface gravity and atmosphere in some regions for giant behemoths to flourish.
Part Five of Ten: The Largest Known Dinosaurs.
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> The largest terrestrial animal known to history is the Argentinasaurus, which by some estimates weighed up to 100 tons. (Meanwhile, Elephants weight around just 6). Some have said this is the absolute size limit for terrestrial land animals.
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> If so, what changes would need to be made to make an organism's design exceed that mass? Like, 200-500 tons?
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The weight of the largest dinosaurs is not estimated with great certainty.
For example, Wikipedia has list of the heaviest sauropodmorphs:
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> Argentinosaurus huinculensis: 50–100 t (55–110 short tons)[16][18][35][31]
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> Patagotitan mayorum: 55–77 t (61–85 short tons)[36]
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> Mamenchisaurus sinocanadorum: 50–80 t (55–88 short tons)[37]
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> Notocolossus gonzalezparejasi: 44.9–75.9 t (49.5–83.7 short tons)[6]
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> Alamosaurus sanjuanensis: 39.5–73 t (43.5–80.5 short tons)[16][18][38]
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> Apatosaurus ajax: 32.7–72.6 t (36.0–80.0 short tons)[39]
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> Sauroposeidon proteles: 40–60 t (44–66 short tons)[40][18][41]
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> Dreadnoughtus schrani: 22.1–59.3 t (24.4–65.4 short tons)[16][34]
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> Paralititan stromeri: 20–59 t (22–65 short tons)[18][42]
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[https://en.wikipedia.org/wiki/Dinosaur\_size#Heaviest\_sauropodomorphs[7]](https://en.wikipedia.org/wiki/Dinosaur_size#Heaviest_sauropodomorphs%5B7%5D)
Many people would disagree with the relative order of the various dinosaurs and with the weight estimates for various species. And of course new large sauropodmorphs are discovered all the time and such lists become more and more obsolete as time passes.
Part Six of Ten: The Largest Not Well Known Dinosaurs?
And of course that list omits the two most controversial and possibly largest sauropod dinosaurs ever discovered, known from now lost fossils.
There was *Amphicoelias fragillimus*, now reclassified as *Maraapunisaurus fragillimus*, which might possibly according to some interpretations been up to 60 meters (200 feet) long and weighed up to 150 tonnes (150 long tons, 170 short tons). Some estimates make it much smaller.
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> The third named Amphicoelias species, A. fragillimus, was known only from a single, incomplete 1.5 m (4.9 ft) tall neural arch, either last or second to last in the series of back vertebrae. Based only on an illustration published in 1878, this vertebra would have measured 2.7 meters (8.9 ft) tall in life.[3] However, it has been argued that the scale bar in the published description contained a typographical error, and the fossil vertebra was in fact only 1.38 meters (4.5 ft) tall.[8] In addition to this vertebra, Cope's field notes contain an entry for an "[i]mmense distal end of femur”, located only a few tens of meters away from the giant vertebra. It is likely that this undescribed leg bone belonged to the same individual animal as the neural spine, but it was never collected or described.[3] In 2018, A. fragillimus was given its own genus, Maraapunisaurus, and reclassified as a primitive rebbachisaurid.[9]
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[https://en.wikipedia.org/wiki/Amphicoelias#Previously\_assigned\_species[10]](https://en.wikipedia.org/wiki/Amphicoelias#Previously_assigned_species%5B10%5D)
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> While M. fragillimus as a sauropod would be relatively elongated, its enormous size still made it very massive. Weight is much more difficult to determine than length in sauropods, as the more complex equations needed are prone to greater margins of error based on smaller variations in the overall proportions of the animal. Carpenter in 2006 used Paul's 1994 estimate of the mass of Diplodocus carnegii (11.5 metric tons (11.3 long tons; 12.7 short tons)) to speculate that M. fragillimus could have weighed up to 122.4 metric tons (120.5 long tons; 134.9 short tons).[4] The heaviest blue whale on record weighed 173 metric tons (170 long tons; 191 short tons),[11] and the heaviest dinosaur known from reasonably good remains, Argentinosaurus, weighed 80 to 100 metric tons (79 to 98 long tons; 88 to 110 short tons), although if the size estimates can be validated, it could still be lighter than Bruhathkayosaurus, which has been estimated to have weighed 126 metric tons (124 long tons; 139 short tons), but is also known from highly fragmentary remains.[8] In 2019 Gregory S. Paul estimated Maraapunisaurus at 35-40 meters (115-131 feet) in length and 80-120 tonnes (88-132 short tons) in weight with a femoral length of 3-3.5 meters (10-11.5 ft) or more, larger than Carpenter's estimation .[9]
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[https://en.wikipedia.org/wiki/Maraapunisaurus#Size[12]](https://en.wikipedia.org/wiki/Maraapunisaurus#Size%5B12%5D)
Possibly the most controversial sauropod fossil of all was *Bruhathkayosaurus*.
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> Bruhathkayosaurus (/bruːˌhæθkeɪoʊˈsɔːrəs/; meaning "huge-bodied lizard") is a genus of dinosaur found in the Kallemedu Formation of India. The fragmentary remains were originally described as a theropod but later publications listed it as a sauropod. Estimates by researchers exceed those of the titanosaur Argentinosaurus,[2](https://en.wikipedia.org/wiki/Surface_gravity#:%7E:text=The%20surface%20gravity%2C%20g%2C%20of,including%20the%20effects%20of%20rotation.&text=Surface%20gravity%20is%20measured%20in,are%20meters%20per%20second%20squared.) as longer than 35 metres (115 ft) and weighing over 80 tons. All the estimates are based on the dimensions of the fossils described in Yadagiri and Ayyasami's 1987 paper, which announced the find.[3] In 2017 it was reported that the original fossils had disintegrated and no longer exist.[4]
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> No total body size estimates for Bruhathkayosaurus have been published, but paleontologists and researchers have posted tentative estimates on the Internet. In a post from June 2001, Mickey Mortimer estimated that Bruhathkayosaurus could have reached 40–44 m (131–144 ft) in length and might have weighed 175–220 tons, but in later posts retracted these estimates, reducing the estimated length of Bruhathkayosaurus to 28–34 m (92–112 ft), and declined to provide a new weight estimate, describing the older weight estimates as inaccurate.[13][13][14] In a May 2008 article for the weblog Sauropod Vertebra Picture of the Week, paleontologist Matt Wedel used a comparison with Argentinosaurus and calculated the weight of Bruhathkayosaurus at up to 126 metric tons (139 short tons).[15] In 2019 Paul suggested that the supposed tibia is probably a degraded femur, in which case its length was slightly greater than that of Dreadnoughtus (1.91 meters) and Futalognkosaurus (1.98 meters). So he estimated its mass between 30-55 tonnes (33-61 short tons) much lower than any previous estimation.[6]
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[https://en.wikipedia.org/wiki/Bruhathkayosaurus#Size\_estimates[16]](https://en.wikipedia.org/wiki/Bruhathkayosaurus#Size_estimates%5B16%5D)
So some tentative and probably inaccurate mass estimates of *Bruhathkayosaurus* put the upper limit of the mass range a little bit above the lower limit of your goal of 200 to 500 tons.
Part Seven of Ten: The Largest Living Land Mammals.
As for elephants, baby elephants are in the human mass range, while adult females average less massive than adult males.
The smallest living elephant species is the African forest elephant *Loxodonta cyclotis*.
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> Bulls reach a shoulder height of 2.4–3.0 m (7.9–9.8 ft). Females are smaller at about 1.8–2.4 m (5.9–7.9 ft) tall at the shoulder. They reach a weight of 2–4 tonnes (2.2–4.4 short tons).[10] Foot print size ranges from 12.5 to 35.3 cm (4.9 to 13.9 in).[15]
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[https://en.wikipedia.org/wiki/African\_forest\_elephant#Size[11]](https://en.wikipedia.org/wiki/African_forest_elephant#Size%5B11%5D)
The middle sized elephant species is the Asian elephant *Elephas maximus*.
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> On average, males are about 2.75 m (9.0 ft) tall at the shoulder and 4 t (4.4 short tons) in weight, while females are smaller at about 2.4 m (7.9 ft) at the shoulder and 2.7 t (3.0 short tons) in weight.[16][17][18] Length of body and head including trunk is 5.5–6.5 m (18–21 ft) with the tail being 1.2–1.5 m (3.9–4.9 ft) long.[5] The largest bull elephant ever recorded was shot by the Maharajah of Susang in the Garo Hills of Assam, India in 1924, it weighed an estimated 7 t (7.7 short tons), stood 3.43 m (11.3 ft) tall at the shoulder and was 8.06 m (26.4 ft) long from head to tail.[16][19][20] There are reports of larger individuals as tall as 3.7 m (12 ft).[15]
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[https://en.wikipedia.org/wiki/Asian\_elephant#Size[8]](https://en.wikipedia.org/wiki/Asian_elephant#Size%5B8%5D)
The largest living elephant species is the African bush or savanna elephant, *Loxodonta africana*.
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> The African bush elephant is the largest and heaviest land animal on Earth, being up to 3.96 m (13.0 ft) tall at the shoulder and an estimated weight of up to 10.4 t (11.5 short tons).[16][17] On average, males are about 3.20 m (10.5 ft) tall at the shoulder and weigh 6.00 t (6.61 short tons), while females are much smaller at about 2.60 m (8.53 ft) tall at the shoulder and 3.00 t (3.31 short tons) in weight.[16][18][19][20] Elephants attain their maximum stature when they complete the fusion of long-bone epiphyses, occurring in males around the age of 40 and females around the age of 25.[6]
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[https://en.wikipedia.org/wiki/African\_bush\_elephant#Size[9]](https://en.wikipedia.org/wiki/African_bush_elephant#Size%5B9%5D)
Since the average mass of male African bush elephants is about the six tons you mentioned for elephants, it is not surprising that many males are more massive, some much more.
Part Eight of Ten: The Largest Extinct Land Mammals:
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> The largest land mammal extant today is the African bush elephant. The largest extinct land mammal known was long considered to be Paraceratherium orgosensis, a rhinoceros relative thought to have stood up to 4.8 m (15.7 ft) tall, measured over 7.4 m (24.3 ft) long and may have weighed about 17 tonnes.[66][67] In 2015, a study suggested that one example of the proboscidean Palaeoloxodon namadicus may have been the largest land mammal ever, based on extensive research of fragmentary leg bone fossils from one individual, with a maximum estimated size of 22 tonnes.[68][66]
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[https://en.wikipedia.org/wiki/Largest\_organisms#Mammals\_(Mammalia)[13]](https://en.wikipedia.org/wiki/Largest_organisms#Mammals_(Mammalia)%5B13%5D)
[https://en.wikipedia.org/wiki/Paraceratherium[15]](https://en.wikipedia.org/wiki/Paraceratherium%5B15%5D)
[https://en.wikipedia.org/wiki/Palaeoloxodon\_namadicus[14]](https://en.wikipedia.org/wiki/Palaeoloxodon_namadicus%5B14%5D)
So known extinct land mammals may have weighed two, three, or four times as much as your 6 ton elephants.
Part Nine of Ten: Vertebrates With More Limbs.
One way to make giant behemoths larger would be to give them more limbs.
the Op asks for a vertebrate body plan, not a tetrapod body plan. So maybe the giant behemoths could be vertebrate hexapods, octopods, decapods, etc. Their torsos might have the same spacing between pairs of legs as giant sauropod dinosaurs had, but with more pairs of legs, thus doubling or more the possible mass of the torso.
If more than four limbs are permissible, the giant behemoths could even have tens or hundreds of pairs of legs and be built like vertebrate caterpillars, centipedes, or millipedes, with a section of torso between each pair of legs with the mass of an elephant or brontosaurus torso.
And possibly such a multi legged creature could be like a giant hippo or crocodile, mostly living in lakes, rivers, or oceans, but sometimes walking on land, and mostly feeding on plants but sometimes getting vital nutrients by eating smaller creatures.
Part Ten of Ten: Smaller Creatures Linked Together To Make A Larger One:
If that is not permissible, possible the species could be contain individuals the sizes of elephants or sauropod dinosaurs, who occasionally join with other individuals to form a hive creature, a really giant behemoth.
Such a larger creature formed by the linking of smaller creatures was in "The Planet of Doubt" by Stanley G. Weinbaum, *Astounding Stories* October, 1935. The linked creatures were based on actual behavior of a species on Earth.
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> ...When they receive a signal from the ship, they hurry back to find it under attack by an immensely long black creature made up of dozens of connected segments. They manage to fight it off and return to the ship. Burlingame decides that the creature is similar to the larval Thaumetopoeidae, which forms processions when it travels from its nest. She hypothesizes that the individual segments link nervous systems so that they all act in unison. As for the shapes in the fog, Burlingame thinks they are analogous to honeyguides, and that they lead the segment-creature to its prey.
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[https://en.wikipedia.org/wiki/The\_Planet\_of\_Doubt[6]](https://en.wikipedia.org/wiki/The_Planet_of_Doubt%5B6%5D)
[http://www.isfdb.org/cgi-bin/title.cgi?47540[18]](http://www.isfdb.org/cgi-bin/title.cgi?47540%5B18%5D)
[http://gutenberg.net.au/ebooks14/1401921h.html[17]](http://gutenberg.net.au/ebooks14/1401921h.html%5B17%5D)
I think that the linking of nervous systems is not found in any Earth animals, but would tend to make the linked super behemoth more or an individual instead of a herd.
And possibly when the creatures link up they might pass partially digested food from the anus of one creatures to the mouth of the one behind it, which would extract some nutrients and pass it on to the creature behind it. That sounds disgusting to me, but it would make them a bit more like a creature instead of a herd.
And it seems to me that as many behemoths as could live in the area as a herd of separate behemoths could link together from time to time to form a more or less hive giant behemoth.
[3]: [https://en.wikipedia.org/wiki/Escape\_velocity#:~:text=In%20common%20usage%2C%20the%20initial,to%201.7%20km%2Fs](https://en.wikipedia.org/wiki/Escape_velocity#:%7E:text=In%20common%20usage%2C%20the%20initial,to%201.7%20km%2Fs)).
[4]: <https://en.wikipedia.org/wiki/Mesklin>
[5]: <https://en.wikipedia.org/wiki/Known_Space#Locations>
[6]: <https://en.wikipedia.org/wiki/The_Planet_of_Doubt>
[7]: <https://en.wikipedia.org/wiki/Dinosaur_size#Heaviest_sauropodomorphs>
[8]: <https://en.wikipedia.org/wiki/Asian_elephant#Size>
[9]: <https://en.wikipedia.org/wiki/African_bush_elephant#Size>
[10]: <https://en.wikipedia.org/wiki/Amphicoelias#Previously_assigned_species>
[11]: <https://en.wikipedia.org/wiki/African_forest_elephant#Size>
[12]: <https://en.wikipedia.org/wiki/Maraapunisaurus#Size>
[13]: <https://en.wikipedia.org/wiki/Largest_organisms#Mammals_(Mammalia)>
[14]: <https://en.wikipedia.org/wiki/Palaeoloxodon_namadicus>
[15]: <https://en.wikipedia.org/wiki/Paraceratherium>
[16]: <https://en.wikipedia.org/wiki/Bruhathkayosaurus#Size_estimates>
[17]: <http://gutenberg.net.au/ebooks14/1401921h.html>
[18]: <http://www.isfdb.org/cgi-bin/title.cgi?47540>
[Answer]
You'll have to deal with the square-cube law. For the bone structure, this could be solved with stronger bones, thicker bones, and/or multiple limbs. For the heart, there's having multiple hearts, or a longer lifespan, so there's less strain. For the lungs, more complex interior structures. For the muscles, make them stronger and with a wider base of support. And for the thermoregulation, either have it live in cold areas or have large sails that increase its surface area-to-volume ratio, and let it cool down.
[Answer]
So, we need a land animal, who weights 200-500 tons.
"6 limbs, at least one set of heart and lungs for each major section of it's body, with extra limbs for support and even skeletal structures designed to reinforce certain muscles to have greater strength, like the jaws for example. The creature lives on a planet with a gravitational pull similar to earth's."
First thing comes to my mind is that, this creature may need a heavy tail dragging on the ground, reducing the mass it needs to carry. Tail may be risen when it needs to, but usually staying on the ground is a good way to balance, sensing something behind, and redestributing some mass to the ground, also adding an additional "limb". Bonus points if it is kinda like an elephant's trunk with high sensitivity so it effectively has a large tail with high motor skills to sweep behind.
With that out of the way, lets continue.
One question, how much flexibility you can accept? Depends on that, I have a few ideas.
**Temporary legs, slimy body**
Imagine a snail or slug, with 6 leg like appendiges. The original creature wouldn't need that much bones and leg muscles to stand up. But it may use those "legs" to more around faster. Some snails have sharp jaws and maybe adding a soft skeleton similar to a shark, could let your creature have enough muscles, enough bones, sharp jaw and additional stuff you may want to add based on bones. Animal could be in form of a large, blanket like shape to reduce the burden on individual organs. And you can add several eyes to let creature see around. Sİnce legs usualyl won't have to support a gigantic mass, they could be more evolved to make attacks or be used as multipurpose appendiges, kinda like an octopus.
**It is a "big animal" but made out of small animals.**
Small organisms forming a one big animal. There are ant colonies acting like a one giant organism, there are even ants holding onto each other to form a structure. Maybe your land animal was actually several different creatures, specialized to fill the roles of different organs and structures inside the creature. Kinda like the portugese man-o-war. The jellyfish made out of cell colonies. <https://en.wikipedia.org/wiki/Portuguese_man_o%27_war> The colonies on leg parts could form chitin like structures to resist against weight or create bouncy structures with special organ systems in itself, allowing interesting leg structures that would otherwise ridicilously hard to form.
**Let it float!**
So, maybe your animal would weight 300 tons "on void" but would weight far less on the earth like planet because... producing gasses less dense than air.
Add a thick atmosphere to the planet, thick enough to let people fly with wings attached to their arms. The creature may support its weight by using the lifting effect of air, with large surface area and storing gasses less dense than air.
With increased surface area similar to wings, you can have enough cooling for your body heat, you can add some skin based oxygen transfer to help with breathing, and transfer some of the organs there even. Many ocean creatures have an air bubble inside them to control their density for going up or down in the water
It would be a "land" animal but the thick atmosphere would lift enough parts of the creature to reduce the requirement of muscle and bone strength.
**Hyperspecialized organ structures**
This one is a bit similar to the colony type animal. Now, imagine your creatures nerve systems, lungs, hearts and system are hyper-specialized with large local organs storing lots of food. This would, effectively divide your creature to different segments that could sustain their own requirements. Though, muscles and bones still remain a challange.
To me, it seems like creature needs at least more legs in this form. Either more legs, or legs are a cluster of limbs formed together that shares the weight, reducing the burden on the individual muscle and bone systems. This would also help as a defence system against losing "some" of the leg mass and falling, lossing the ability to move in general. Many quadruped animals on earth can still run limitedly on 3 limbs. Your creature should have at least thsi much contingency plan against such wounds instead of falling on leg injuries and waiting to die.
**Strange organs on strange beings**
Let your creature have a magnetic parts, and repel itself with the earth's magnetic force. Maybe the creature's upper bones or parts of its skin is covered with special metal, acting as a magnet to repel itself against the gravity.
Now the planet would need some revisions based on its magnetic field, but your creature can effectively weight 200-500 tons, have 6 or maybe less legs, and can even have a metal armor. Planetary magnetic field may be strong enough to repel the creature just enough to make it lighter on the planet.
An interesting thing you can add is, adding a piezoelectrical <https://en.wikipedia.org/wiki/Piezoelectricity> material to the bones, allowing the creature to generate electricity to keep its metals magnetized. If you think this is too far-fetched, there is a real creature forming a metal outer shell. <https://en.wikipedia.org/wiki/Scaly-foot_gastropod> add an electrical eel's electricity, and here you go. A creature that forms iron clusters on its body and magnetizes them. Add a tail for grounding the excessive charges to protect organs from electricity.
Maybe I got a bit off-topic.
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the dinosaurs and birds (which are also dinosaurs) are quite adept for being scaled up so it's likely your Behemoth has a body plan similar to one. but even still a sauropod over 100 tons to exist in modern day earth seems unlikely so for a creature that massive to exist certain environmental circumstances would have to be in place.
# Lower gravity
would allow creatures to grow to larger sizes which is why the ocean has some of the largest animals alive
# More food
even if a creature could grow to be as large as an island if it is unable to find enough food to sustain in's self it won't which is one of the main reasons why land carnivores often don't grow to be as large as herbivores
# More oxygen
likely a side effect of more vegetation increased amounts of oxygen would fuel the metabolic requirements for large animal locomotion
# Redundant organs
multiple hearts, pairs of lungs, possibly even proto-brains would all be beneficial to a creature larger than a blue whale helping to carry oxygen though out the body and making it's reaction time less abysmal
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The reason why land creatures don't grow large is **gravity**.
On Earth, land animals can grow to 100 tons, as that is the maximum weight that their skeletons can support. For insects that is even harder, as they have exoskeletons, which would collapse under a much, much lower mass limit. That is why you don't see 5-foot bugs wandering about here. Even with high oxygen content, your skeletons just can't support the massive weight. In water, however, the buoyant force is much stronger, which cancels out a large part of gravity, which allows animals to get much larger in the oceans (And that is why the oceans are a "low-grav" environment).
Maybe if you got lower gravity, they you could get larger land vertebrates.
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Now [octopuses](https://en.wikipedia.org/wiki/Octopus) are quite smart already capable of camouflage and puzzle solving.
[](https://i.stack.imgur.com/ieWCw.png)
given this I was wondering whether Octopuses could [Convergently evolve](https://en.wikipedia.org/wiki/Convergent_evolution) sapience (human level intelligence) and what evolutionary pressures would lead to them doing so?
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Any potential answers to "what makes makes a species evolve sapience" currently suffer under a major limiting factor: we have exactly one (1) example to extrapolate from.
With that caveat, the current rough consensus is that the key factors are **strong reliance on *tool-use* and *social cooperation***.
# In Humans
Physiologically, humans aren't that impressive. We don't have bone-crushing jaws, sharp claws, tough hide, horns, et cetera. Our evolutionary ancestors made up for that by living and hunting in packs/tribes for strength in numbers, and by using tools to offset their physical disadvantages. All surviving Great Apes species — which includes *Homo Sapiens* — exhibit this behavior, as do a large number of other species, but we've never discovered any evidence of any other evolutionary genus producing the level of intelligence exhibited by *Homo*.
The end of the Pliocene Epoch was marked by a series of rapid, drastic climate changes that threw ecosystems across the world into chaos. It appears that the *Homo* genus developed as it has because it responded to the instability by relying even more on tools and social cooperation, rather than by physiological changes like the other genera. *Homo* individuals that cooperated better and used tools to greater advantage were more successful at reproduction than their less adept peers, leading through natural selection to brains of ever increasing size and complexity.
# In Octopuses
Octopuses are of course known to be tool users, but they do not currently (as far as we are aware) rely on tools to the extent that early *Homo* members did. We also observe them to be solitary, rather than social.
Thus, for a species of octopus to follow the same path towards intelligence that humans did, there would need to be environmental pressure to change those specific behaviors. Something that gives a high reward to individual octopuses who work together and make extensive use of tools to augment their natural abilities.
Once that pressure exists, there are a few additional small but significant changes that need to happen in the octopuses themselves.
## Optic Glands
This is the most important one. Similar to the human pituitary gland, an octopus's optic glands (one next to each eye) play a significant role in sexual maturation. Unlike the human pituitary gland, an octopus's optic glands also shut down its digestive system upon sexual maturity and octopuses — male and female — starve to death soon after reproducing. However, in "Hormonal Inhibition of Feeding and Death in Octopus: Control by Optic Gland Secretion", published in *Science* magazine (Vol. 198, Dec. 2, 1977), it is shown that severing the optic glands after a mating event allows octopuses to live two to three times as long post-coitus before succumbing to apparently age-related illnesses. Which leads me directly to...
## Age
Currently, the longest-lived (known) octopus species, the Giant Pacific Octopus, only lives about five years. Clearly, this is not conducive to building social long-term structures. But if the digestion-inhibiting effects of the optic glands is suppressed or removed (through natural mutation or artificial meddling) without affecting fertility, octopuses might be able to reproduce more than once, which would start to naturally select for longer healthy lifespans. This naturally helps with mental and social development, and it also allows for...
## Childcare
Currently, octopus infants are all orphans left to survive on their own, which leads to very high child mortality. Longer-lived octopus parents could potentially help raise their offspring, boosting the odds of those offspring surviving to reproduce and pass their homemaker genes along. This can also provide additional evolutionary pressure to live longer.
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A potential alternative to letting octopuses survive reproduction is having some octopuses not reproduce. A longer-lived infertile (or merely celibate) octopus could take on the role of caregiver for eggs and infants, which would be an evolutionarily beneficial role as long as some of the infants it raises also become caregivers for the next generation.
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They need some kind of complex communication. Before that, they need to start some kind of social life instead of being solitaries.
Absence of an opposable thumb does not seem to prevent them from using tools.
Community behaviour is important to be able to bequeath a culture to next generations.
This is a giant problem for cephalopods as it's more a characteristic of mammals and birds.
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**No**
It can't *conveniently* evolve intelligence. It may be able to evolve intelligence out of necessity, but not out of convenience. Evolution isn't 'I'd like to look blue because I think it makes me look better', it's 'Evolve to blue to camouflage yourself or *die*'. Death is one heck of a motivator. And, as it happens, I think an octopus could evolve sapience based on necessity, assuming the same rules of evolution for humans. Am I nitpicking when I say that an octopus can't *conveniently* evolve, but could necessarily evolve? A little bit, sure, but I think it's very important to be precise when we discuss scientific terms because if we don't, then that's where miscommunication and confusion starts. Speaking of which, what's sapience anyways? (Well, you've defined it as 'human-level intelligence, so I'm using that.)
The limiting factor here is, of course, the brain. We're not *quite* sure what exactly it is about the human brain which uniquely makes humans *that* intelligent. It probably has something to do with the brain mass to body mass ratio. There's also a minimum size requirement. Not to mention that there's a complexity requirement when it comes to the brain's design. Could an octupus ever acquire such a brain? Maybe. There's nothing prohibiting such a structure from naturally evolving in their head if such a structure naturally evolved in a human head.
In order to evolve intelligence, octopi would need two things - they would need to get bigger and need an environment which would reward intelligence. What I have in mind is suppose that humans decide to do something really foolish like melt all the arctic and antarctic ice, which floods the world. This would, in turn, create new and exciting biomes for aquatic creatures, like the new 'sunken city' biome, which would lead to new evolution as creatures that specialized in the sunken city biome came around. One of these might just be a new breed of octopi which grew larger due to new predators and smarter to manipulate the environment.
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While reading [this question](https://worldbuilding.stackexchange.com/questions/168345/feasibility-of-humanoids-that-evolved-from-non-primate-mammals) about how non-primate mammals could develop a bipedal stance, I became curious about the broader reasons why animals could evolve to walk on two legs.
I found some insights at [this question](https://worldbuilding.stackexchange.com/questions/87928/evolution-of-a-feline-humanoid-specifically-upright-walking-and-fingers), which inquires about felines in particular. The accepted answer states,
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> Moving to trees and/or a rocky area would help. Hands and an upright posture are good for reaching and carrying things. They are also good at manipulating things and tool use. An upright posture is also good for spotting predators.
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This is a great explanation of why bipedalism might arise **on land**, but I don't think it holds up underwater.
* There are no fruit-bearing trees underwater, and I can't think of similar plants that creatures would need to be "upright" to reach or climb.
* Even if an alien world has marine trees (big kelp maybe?) I imagine swimming vertically is a more efficient way to reach food. For instance, even though crabs have legs, they can swim in the open ocean. If you can swim vertically, why would evolving to reach vertically be worthwhile?
* While being vertical might help spot predators in a grassy plain, much of the ocean is relatively flat and featureless. I imagine most prey can see predators coming regardless of height.
Given the drastically different environmental factors posed by life underwater, **what environmental factors, if any, would cause bipedalism underwater?** What would a humanoid-fish-or-crustacean-producing biome look like?
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Given that a humanoid form on Earth comes from tree dwelling creatures that start roaming on a Savannah, arguably one biome or environment that *may* encourage a humanoid form would be [Kelp Forests](https://en.wikipedia.org/wiki/Kelp_forest).
The problem in a marine environment is that there are very few places to hide, and hydrodynamic form is generally more beneficial than an articulated arm. But, what if you had a creature that specialises in hiding in kelp forests, grabbing on to the kelp and using it as leverage to move out of the way of a fast oncoming predator? They may also end up becoming ambush predators in time, using some kelp as a launching point.
The point being, arms with hands that are designed to grip items like kelp will later be used to grab other things that give them an advantage in the environment. They may one day be used to throw stones or sharp shells or the like at other creatures for defence or hunting. In any case, water is one of those environments where hands are generally *not* useful, let alone arms, so you need to change things up a little to force out a humanoid form.
But when you get right down to it, that still entails having to grab something in the first instance, whether that is a tree branch or a line of wavy kelp. The fact that it could act as a hiding spot from the creatures in the open sea is probably all the more reason why it may happen, but in order for it to do so you'd probably need much larger kelp forests that are around in the one place for a lot longer than they currently have been.
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I'm sorry to say, but nothing would, unfortunately. There are very good reasons there aren't any fish with legs. Any creature that isn't (partially) land dwelling would not have need for legs over something like fins or tails. Any directional movement underwater is significantly easier with fins and tails, and bipedalism would simply have no evolutionary advantage whatsoever.
Arms are a different thing, they could be useful when higher intelligence is formed, for the manipulation of tools and the like. Using tools with fins is near impossible, and just using mouths, jaws, or beaks would not be ideal.
This means in your world the possibility of merfolk or merfolk-like creatures would be much higher than an ocean dwelling bipedal humanoid. Although from an evolutionary standpoint, it would probably more likely to evolve a sentient squid-like or tentacle based creature over merfolk.
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Many underwater creatures have legs. They're the kinds of creatures that are bottom-dwellers, like crabs, lobsters, etc. So the only problem you have to solve is: what would cause a bottom-dweller to have only two legs instead of 6/8/10/12?
The advantage of bipedalism is the ability to move faster *over long distances*. Not faster over a short interval--there are many creatures that are faster sprinters than humans--but very few creature can compete with humans at running a marathon. Compared to 4 legs, it's very efficient at converting energy to movement on land.
The problem with being underwater is that the weight of water on earth is such that it makes moving with feet much slower than moving by swimming.
Therefore: **if the liquid being moved in had significantly less weight than water**, I think that's the one situation where the benefits of bipedalism could make a bipedal creature underwater feasible.
How do you get that to happen?
1. Low-gravity planet. This is the simplest solution.
2. A different liquid than water is the one being moved in, one with much less density. This is the complex/far-fetched solution so I'll spend more time explaining, even though I think the first solution more viable.
For something lighter than water to be the liquid, this would probably require the planet to have significantly higher pressure and/or temperature. For reference, Jupiter is ~50% liquid hydrogen because of its insane pressure and weight. However, Jupiter's environment doesn't work for our purposes in many ways; also hydrogen is very reactive so wouldn't work as the neutral medium for life to exist in.
So instead we pick helium, which is basically inert. It has a molecular weight of 4 g/mol instead of 18 g/mol for water. [1](https://www.engineeringtoolbox.com/helium-d_1418.html) I'm not completely sure if helium would work as the medium for life to exist in, you'd have to ask a biologist that, but *if it did* then maybe the following would work:
[According to this chart](http://ltl.tkk.fi/research/theory/helium.html) at a pressure of 4 mPa (39 atm) and temp of 100K (-280F) you would have a substance that is mostly liquid helium, somewhat gaseous helium. Can life exist in those conditions? Maybe not, but I wanted to at least give you the groundwork for this idea if you want to research it further.
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Bipedal aquatic fish could evolve from lungfish, that evolved to store air in their lungs, and live near the sea-floor. To avoid floating up, they evolve to have dense pelvic fins, which adapt into legs. This would cause the lungfish to become upright walkers
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I want to try writing some stories based on "hard science" but set historically and based on the scientific knowledge of the time. I'm thinking probably 1800s or early 1900s, but willing to go back further if it makes things interesting.
My question is where can I go to get information on what we used to believe about space? It's easy to google what we know now, but when for example was it discovered that space is vacuum and not ether etc. I can google individual topics but I'm after a 'history of space science' resource that covers what we discovered when and what we believed before.
I'm not asking for all this information in an answer but suggestions of online resources where I can access get this information.
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* [Thomas Dick](https://en.wikipedia.org/wiki/Thomas_Dick_(scientist)), *[Celestial scenery](https://archive.org/details/celestialscenery00dick), or, The Wonders of the Planetary System Displayed*, New York, 1838.
* [Ormsby MacKnight Mitchel](https://en.wikipedia.org/wiki/Ormsby_M._Mitchel), [*The planetary and stellar worlds*](https://archive.org/details/planetarystella00mitc), New York, 1852. *Id.*, [*Popular Astronomy: a Concise Elementary Treatise on the Sun, Planets, Satellites and Comets*](https://archive.org/details/popularastronom00mitc), New York, 1860.
* [Camille Flammarion](https://en.wikipedia.org/wiki/Camille_Flammarion), [*Astronomy for Amateurs*](https://archive.org/details/in.ernet.dli.2015.110858), 1903.
* Walter W. Bryant, [*A History of Astronomy*](https://archive.org/details/AHistoryOfAstronomy), London, 1907.
* Peter Doig, [*A Concise History of Astronomy*](https://archive.org/details/AConciseHistoryOfAstronomy), London, 1950.
* Rudolf Thiel, *[And There Was Light](https://archive.org/details/AndThereWasLight) -- The Discovery of the Universe*, London, 1958. (This may be the closest to what you are after, a coherent narrative of the development of our understanding of the Cosmos.)
All links go to freely available copies at [Archive.org](https://archive.org/).
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It's hard to talk about hard science when there was no real space science yet.
You can look at literature dealing with "space travel" in the past. They usually contain hints of what was, back in the time it was written, the knowledge about space travel.
Starting from more recent works I can remember the following:
* [*The first man in the moon*](https://en.wikipedia.org/wiki/The_First_Men_in_the_Moon), H.G. Wells 1901
* [*From the Earth to the moon*](https://en.wikipedia.org/wiki/From_the_Earth_to_the_Moon), Jules Verne 1865, and its sequel, [*Around the Moon*](http://www.gutenberg.org/ebooks/16457)
* *[Off on a Comet](https://www.gutenberg.org/files/1353/1353-h/1353-h.htm), or, Hector Servadac*, Jules Verne, 1877. *"The story starts with a comet called Gallia, that touches the Earth in its flight and collects a few small chunks of it. The disaster occurs on January 1 of the year 188x in the area around Gibraltar. On the territory that is carried away by the comet there remain a total of thirty-six people of French, English, Spanish and Russian nationality. These people do not realize at first what has happened, and consider the collision an earthquake."* ([Wikipedia](https://en.wikipedia.org/wiki/Off_on_a_Comet)). It's a fantastic voyage through the Solar System, as imagined by a science-fiction author in the second half of the 19th century.
* [*Orlando furioso*](https://en.wikipedia.org/wiki/Orlando_Furioso), L. Ariosto, 1532
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Some Answers have suggested reading old science fiction interplanetary stories for information about popular ideas about astronomy.
I may note that many science fiction novels used ideas that had been abandoned by professional astronomers decades earlier. So many science fiction stories are not good examples of what professional astronomers believed when they were written.
*Somnium* Johannes Kepler 1634. <https://en.wikipedia.org/wiki/Somnium_(novel)>[1](https://en.wikipedia.org/wiki/Somnium_(novel)) This is as much a description of the moon according to contemporary science as a novel.
*The Man in the Moone* Bishop Francis Goodwin, 1638 <https://en.wikipedia.org/wiki/The_Man_in_the_Moone>[2](https://en.wikipedia.org/wiki/The_Man_in_the_Moone)
The Great Moon Hoax 1835. <https://en.wikipedia.org/wiki/Great_Moon_Hoax>[3](https://en.wikipedia.org/wiki/Great_Moon_Hoax)
"Hans Phaal - a Tale" Edgar Allen Poe 1835. <http://www.isfdb.org/cgi-bin/title.cgi?71384>[4](http://www.isfdb.org/cgi-bin/title.cgi?71384)
"Mellonta Tauta" Edgar Allen Poe 1849: <http://www.isfdb.org/cgi-bin/title.cgi?55038>[5](http://www.isfdb.org/cgi-bin/title.cgi?55038)
Percy Gregg *Across the Zodiac* 1880.
John Jacob Astor IV *A Journey in Other Worlds* (1894)
*The Lunar Trilogy* of Jerzy Zulawski (1903, 1910,1911): <https://en.wikipedia.org/wiki/The_Lunar_Trilogy>[6](https://en.wikipedia.org/wiki/The_Lunar_Trilogy)
Edgar Rice Burroughs *A Princess of Mars* (1912)
Otis Adalbert Kline *Maza of the Moon* (1930)
E.E. Smith *Spacehounds of IPC* (1931, 1947)
And many others.
There is a website devoted to classic science fiction stories set on other planets in the solar system up to the beginning of the space age. It is about the old fictional solar system. <https://www.solarsystemheritage.com/>[7](https://www.solarsystemheritage.com/)
The Science Fiction Encyclopedia lists many examples in the articles "Planetary Romance": <http://www.sf-encyclopedia.com/entry/planetary_romance>[8](http://www.sf-encyclopedia.com/entry/planetary_romance) and "Space Opera": <http://www.sf-encyclopedia.com/entry/space_opera>[9](http://www.sf-encyclopedia.com/entry/space_opera)
And no doubt the articles on the Moon, Mars, Venus, and other worlds mention many examples.
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Once we all swallowed into the idea of a heliocentric solar system, we knew that space was really really big. But, we believed that there was an edge to the universe, that it was finite in size. We also believed that there was space and there was time, two unique things.
Once, after drinking the kool-aid of space-time in the early twentieth century, we conceive that the universe is infinite and that space and time are linked together in a hyper-manifold, or some such mathematical handwaving term.
We used to know that you could travel at any velocity you wanted if you could generate enough force. We now know that the universe has a speed limit.
As some one already pointed out, we used to know that space was composed of the sublumiferious ether, that light was waves in the ether like sound is waves in the air, and waves are waves in the water.
We used to know that the universe was analog. That anything we could measure or conceive of could be quantified by any real number between 0 and $\inf$. Mass, Distance, Charge, etc, ad naseum, could be as small or large as it needed to be.
We now know that much of things we see are quantized in tiny tiny bits or derived from algebraic combinations of these quantized values of length, mass, and energy.
This means we know that things can only be so small, and we know that things can only so big — too much mass and you kind of fall through reality and become a singularity.
We used to know the shortest distance between two points was a straight line, with Einstein-Rosenberg Bridges, that idea might be considered in doubt.
We used to know that light traveled in straight lines. We know that isn’t true, mass bends the path of light through its assertion of gravity.
We used to know that time travel was possible. We know now that that would violate laws of conservation of energy and entropy.
We used to know that space and time were independent of how fast you travelled. We know now that is not true.
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**Would a computer using biological components as an interface be any good? Would that protect it against hacking? Or provide more complex processing?**
The way I'm going with this is that computers are at risk of getting hacked when they connect to the network. However as I understand biological computers AKA brains cannot be hacked like computers. So would using neurons to transmit and translate information between the processor and the transmitter/receiver get rid of the risk of a virus getting through? Sure neurons are much slower in terms of computational speed and may not have time to recover between actions, but would that interface provide any protection? If it doesn't then what would be a good alternative?
Also can using biological components provide some other advantage to a computer, like flexibility or better pattern recognition? Or would it be too much of a nuisance to be any help?
Edit: Thank you for your answers. This has been very informative.
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**No**
The problem with creating a "unhackable" system is that it would solve the [Halting Problem](https://en.wikipedia.org/wiki/Halting_problem). The problem asks if it is possible to build a system which takes some source code as input and outputs whether that code will stop eventually or if it will run forever. It was proven that such a system would be impossible to build.
We can reconfigure the halting problem to search the source code to see if it will ever execute illegal instructions such as unauthorized data access or modification and you can see that perfect virus scans are essentially the same thing as a halting problem system. That is to say, impossible to build.
Never have we mentioned what material the system is built from, electronics, software, or neurons. That is because it does not matter what material you use, the halting problem was proven impossible in the realm of logic and therefore proves it cannot be done in reality.
The only thing biological components will do to your system is:
1. Make it more expensive to build your system, since you will need engineers experienced in traditional electronic software as well as "wetware"
2. Increase the maintenance cost for the previous reason, plus because wetware degrades, gets sick, becomes tired, etc
3. Decrease the performance of your system, because wetware doesn't communicate quickly and because the two systems will have to translate all data between the different formats used
4. Increase the number of production issues caused since, presumably, wetware is less predictable than hardware and thus programs run on my system may behave slightly different than the same program run on yours
5. Increase the political controversy around your product as people ask if the system is alive and if it is cruel to utilize it.
Overall, wetware is a more expensive, difficult to maintain, less performant and controversial way to achieve not as much as what traditional systems can do. The only advantage they *might* have is parallel processing, but even that is being done fairly well with traditional systems.
So, no.
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It is not true that human brain "has never been hacked". Humans have been made to behave against their true intentions, do the things that actually would never be doing on their own - just by being cheated, seduced, misinformed, provoked and the like.
Well known examples outside the scope of the "human brain" are impressive: a virus turns all the complex machinery of the infected cell just to produce more viruses.
Hence the initial assumption is probably wrong: it is not unusual for one biological system to "hack" another, it happens all time and not just between humans. From the other side, there is no reason why neural networks could not provide additional protection against hacking, same as any other advanced technology.
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**No**.
The best protection is air-gapping; don't allow untrusted information into the system in the first place. The next best protection is to thoroughly vet incoming information. This may take the form of requiring incoming information to conform to a very specific format that minimizes the potential attack space. (It's a pity [Roland Hughes](https://www.amazon.com/Roland-Hughes/e/B001JRZVAM), AFAIK, isn't part of the community; he has a *ton* of interesting stories in this area.)
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**We already have this!**
A primitive human could benefit from a canine's keen senses and biological weaponry. The dog can anticipate some threats, deal with some itself, and in other circumstances buy the human some time for a different and more robust response. That is why our species domesticated dogs. Or the dogs would probably turn that on its head and point out how humans can anticipate and solve problems beyond the abilities of dog, and so humans are valuable additions to the pack. A smart dog will take its cues from the human and at the end everybody eats.
Computers use human brains right now. I install protective software on the computer. I decline to open suspicious emails and websites. I am careful what I plug into my computer in case it has malware or a virus. I can perceive and act on threats to the computer. And all the wetware I use on the computer's behalf comes with build in apparatus to sustain it, like my circulatory system and gut.
A computer can definitely benefit from a human associate. Humans are unsurpassed at perceiving order in chaos, rapid pattern recognition, suspicion and strategy. The way to use biological neurons to help defend computers is to have human beings doing the job, like we do.
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> Would a computer using biological components as an interface be any good?
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> Also can using biological components provide some other advantage to a computer, like flexibility or better pattern recognition?
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The *Terminator* movie series gives a tangible example of where biological components (i.e., living skin) could be utilized, albeit not for the betterment of mankind. It's certainly conceivable.
Biological entities are generally able to reproduce, so biological components could plausibly self-improve over time.
In computer gaming, it's often more interesting to play against humans, so a biological AI might be interesting for gaming (and may even have military applications).
As another point along these lines: [3D-printed organs](https://3dstartpoint.com/3d-printed-organs-research/).
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> Would that protect it against hacking?
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> So would using neurons to transmit and translate information between the processor and the transmitter/receiver get rid of the risk of a virus getting through?
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It would introduce a lot of incompatibilities, so things like today's computer viruses and trojans would not be useful. But if it's possible to create a computer-biological interface, and a hacker has access to it, then it's plausible to trick the computer in some way.
If it were like a human brain, then they're already able to be manipulated in various ways.
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> Or provide more complex processing?
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This is plausible. Brains have abilities that computers generally don't have, such as the ability to learn from experience. But they also make mistakes.
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> If it doesn't then what would be a good alternative?
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The only real way to prevent hacking is to isolate the computer, such as with [missile launch systems](https://www.shocktech.com/applications/missiles-launch-vehicles/). And even then, it might still be physically hackable if someone were to do so in person.
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> Or would it be too much of a nuisance to be any help?
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It's hard to say. E.g., if a brain could be hotwired to perform computations, it might massively outperform a pure computer and have benefits such as learning and growth (but it's a big "if").
[Answer]
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> Also can using biological components provide some other advantage to a computer, like flexibility or better pattern recognition? Or would it be too much of a nuisance to be any help?
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Human brains are biological computers that are superior to silicon ones at many functions (yet infirior at many others). One could argue that it would make sense to develop a biological computer to make use of those adventages.
I would challenge that. I'm no expert at this but afaik the main differences between computer and human brain architecture are that:
1. brains are analog while CPUs are usually digital.
2. information processing is much more parallelized in case of brains
I see no reason why those qualities couldn't potentially be achieved with silicon-based architecture but there might be one.
Having said that, I see some really good potential adventages of biological CPUs:
* ability to self-repair
* ability to change it's own architecture at will
* ability to self-replicate (would make production very cheap, could also allow for autoscaling)
[Answer]
Memory would actually be vastly improved by biological interfacing. According to a May 2010 [Scientific America](https://www.scientificamerican.com/article/what-is-the-memory-capacity/) article, the human brain is capable of memory storage of 2.5 petrabytes of information (or 2.5 million gigabits... most commercially available computers have a single or double digit gigabit storage). To give you an idea of how much digital information this is, if you you were to have a device with the memory storage of a human brain attached to a TIVO and set to record your favorite channel until memory was full, it would record 300 years of broadcasts before it was filled up.
It is important to know that this still doesn't equate to actual biological memory (i.e. the stuff you can recall) as there is no way to convert your fond childhood memory into a quantifiable digital memory value (a byte). But the storage capacity of a human is still thought to be unable to be met in a human life time.
[Answer]
**No.**
The network is there to send and receive information. This information has to be translated through programs to make them useful for you. So if you download a game first a program (like the newest Wyndowz) has to translate it and make it into its own program to run.
If a biological system first processes it... what remains of the program? Unless the biological program only processes visual information and presents it in the form of a video or something its not going to be any use. Even then if you convince the biological programs to add in a feedback loop where it shows just dicks over and over again and is too busy to accept new information its still a virus. A virus is basically nothing more than a program that does something you don't want. So if the brain prevents a virus from running then it would also prevent you from downloading any other program.
[Answer]
## Would using neurons to transmit and translate information between the processor and the transmitter/receiver get rid of the risk of a virus getting through?
Yes. What you're describing is a technique already implemented without using biological neurons attached networks called "sandboxing". You can create isolated contexts that are only allowed access to the resources set-aside for them. Cellphones use them for apps. Even web browsers use these with CORS (cross-origin resource) limitations. Any application can run in the system, but it is required to live within those limitations.
Many previous answer cited the Halting Problem as proof that it is impossible to absolutely determine the behavior of a system allowing any input. It is true that for a program that allows **ANY** input, and when you want a **absolute** solution. But this is, in my opinion, a mistaken application of the Halting Problem. You could cite [Zeno's Paradox](https://en.wikipedia.org/wiki/Zeno%27s_paradoxes) as proof that you can not cross the room, but would be a similar, in my opinion, mis-application.
If you are willing to disallow certain inputs (perfectly acceptable in a security context), and you are willing to settle for "good enough", you can get pretty good answers.
You can also ring out complex attacks by translating across machine languages : in-and-out of analog signals, in-and-out of some human-readable representation using a limited character set (XML without CDATA).
There is also a security technique called "air gap" security, which is a low tech version of exactly what you propose. In an "air gap" there is a human operator servicing requests sent in on the network. If everything looks right to the human operator about the request, he or she will go to a completely disconnected other system (paper filing cabinet, computer in a different room, or different computer at same desk with all its own peripherals and unconnected to the outside world) to get the answer. Answer in hand, the operator will then type in the answer to question without the outside-connected computer ever coming into contact with the secure systems (not even a USB drive)
As a historical side-note: air gap security is what Mrs. Hillary Clinton defeated when she ordered staffers to hand-copy top-secret data from an air-gap protected secure system to her personal one.
## Can biological computers AKA brains not be hacked like computers?
Unfortunately, brains can be hacked in a different, but similar way to computers. "[Brain Games](https://www.netflix.com/title/80029103)" is a good series devoted to showing examples, but there are several other excellent shows.
Social Engineering (hacking the human beings) is, I've been told, part of most successful system breaches.
However, human brains are excellent at pattern recognition and classification. This is why neural networks (which are software designed to mimic the human brain) is very good in this role. Pattern recognition is used in anti-virus software to identify "suspicious" software, and is used on higher-end network routers to identify and handle "suspicious" activity.
It should be noted that a lot of what is being sold as "AI" on the marketplace these days is basic line-fitting services like Microsoft Excel had in the 1980s. Linear regression is different than classification, and classification is different than general intelligence.
General intelligence is a set of software designed to mimic the human brain that also has a few days, weeks, months, years of actual experience being "taught" by a "teacher" (which may be a fast-moving program with questions and answers). A general intelligence, like a human monitor in the same role, is looking at a much bigger picture for anything unusual. General intelligence may include procedures so that it can formulate explanations (hypothesis) for unusual behavior, and test those ideas by making changes, or dig in and do it's own research; consulting a broader database of possible explanations. A general intelligence may even manage it's own "focus" and "attention", performing time management to pay attention to the parts of the problem that appear most likely to yield results. It can also take unilateral action in seemingly dire circumstances (closing a connection or shutting down and isolating a system), or ask for help in urgent situations where it feels it's not going to be able to figure out what's happening in an acceptable amount of time.
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[Question]
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It is a known fact that magnesium is a very important part of photosynthesis and chlorophyll. I have looked everywhere to try to find out this question but I have never really gotten a solid answer.
What is magnesium's role in the chlorophyll molecule and what if it was replaced with another alkaline earth metal, like beryllium or calcium?
[Answer]
You couldn't just replace the Magnesium directly without making other changes.
Taking beryllium as the first example.
In Plant-like organisms there are at least two different types of Chlorophyll, they work in pairs synergistically, one as an oxidizing agent and one as a reducing agent in the [ATP and NADPH](https://en.wikipedia.org/wiki/Nicotinamide_adenine_dinucleotide_phosphate) cycle (synthesis of glucose), (more on [Photosynthesis](https://www.rsc.org/Education/Teachers/Resources/cfb/Photosynthesis.htm)). You would need to consider binding energies between the Mg+2 ion (Cation) and any corresponding Anion. Binding energies for beryllium are much higher, meaning you would need higher-energy photons to be absorbed by your new version of chlorophyll (let's call it NVC).
The thing about the chlorophyll molecules is that they have tails acting as antennas, tuned to a specific [wavelength of light](https://en.wikipedia.org/wiki/Light), corresponding to it's [absorption spectrum](https://en.wikipedia.org/wiki/Absorption_spectroscopy#Absorption_spectrum). In the case of your NVC, you'd need to tune it to a higher frequency - ie. truncate the tail of the molecule, and in a wavelength-specific way.
The electromagnetic spectrum is shown in [this table](https://en.wikipedia.org/wiki/Electromagnetic_spectrum), higher energies (shorter wavelengths) nearer the top.
I'm not enough of a physical chemist to tell you how you can do this, but I can say that beryllium would likely lead to your plants needing ultra-violet and beyond energy photons, perhaps even into the x-ray spectrum to work, if it would at all.
Edit: calcium's binding energy turns out to be less than magnesium, perhaps a longer-tailed NVC is in order and absorption of infra-red light would be the method of photosynthesizing.
[Answer]
I initially thought this is not about world building, but then you asked about switching magnesium for something else.
Most chlorophylls have mangesium in their chlorin core. Chlorophylls absorb energy from light and then transfer that energy to other chlorophylls [by ressonance](https://en.wikipedia.org/wiki/F%C3%B6rster_resonance_energy_transfer). This is a very delicate and fine tuned (no pun intended) mechanism. Changing any part of the whole molecule changes its color - seriously, check the difference between chlorophylls A and B - and thus:
* Changes the light wavelengths that can be absorbed
* Changes the molecule pairs that can resonate to absorb energy
In theory you can make any change to the molecule as long as it does not become poisonous and still absorbs light in some spectrum. For example, [pheophytin](https://en.wikipedia.org/wiki/Pheophytin) is a blueish chlorophyll.
In practice, though, nature selects for what is most efficient. Red and purple-leaved plants do exist, but looks like the green variety of chlorophyll is unmatched in photosynthetic efficiency. A different planet with a different parent star might make it so that some other color is best. But under a sky that is blue most of the day and red by the end of it? Go for something that absorbs those colors, causing the leaf to be green. In other words, magnesium-based chlorophylls.
Also notice that the atom you wish to use must be abundant. You would be hardpressed evolving niobium-based chlorophylls regardless of their color, for example.
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[Question]
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I'm just trying to write a RPG adventure for a sci fi company. So when I have to figure out what kind of orbits, masses, major axis, etc are needed for the system I need to design and I see:
$T=2\pi$ times the square root of etc., etc.
Yeah, that's not going to work. I need a tool so that I can design a binary system with a planet orbiting a dim star that in turn orbits a bright star in its habitable zone and this planet is eclipsed by its dim star 6 earth months out of every 24 earth months, approximately. And still be in a habitable zone.
I can see that if the dim star orbits the bright star every two earth years while the planet orbits the dim star every earth year, my eclipse needs will be met. Alternately, if the planets orbital period is two earth years and the dim star orbits the bright star every earth year, my eclipse needs will be met. But having the equations and knowing how to do anything with them, well, as I said, I need a tool.
Anyone have one where I can input masses and distances trial and error until I get the results I need?
[Answer]
Better than that; there's a game that will do it.
Steam has a game called [Universe Sandbox](https://store.steampowered.com/app/230290/Universe_Sandbox/) where you can line up different planets, stars, et al with different masses and trajectories. I've never tried it but as I understand it the game is capable of simulating the orbits of planets, stars and the like in a way that you can graphically see the results.
In point of fact I believe there are a couple of celestial simulation games on Steam but this is just one that appeared in my discovery queue one day and I remembered it. Have a look for yourself but I suspect that this would solve a lot of your issues.
[Answer]
The arrangement you wish does not seem feasible.
If by "dim" star you mean a star that is dimmer than our sun, you are probably thinking of a [red dwarf](https://en.wikipedia.org/wiki/Red_dwarf). Such stars are thought to be far from habitable, because:
* The habitable zone around them requires a tidal lock;
* They are usually flare stars, which means the star facing side of planets in the habitable is toast;
* They vary their luminosity a lot. Even then, it is mostly infrared. Those stars have an average surface temperature of 1700K (compare with ~5600K of the Sun).
* The proximity to the star means that the star's own magnetic field will probably overcome the planet's, meaning little to no protection from solar wind, meaning no atmosphere.
If that is not discouraging enough: if a binary system has evolved in a way that has caused one star to be much brighter larger than the other, then it is most likely a [semidetached system](https://en.wikipedia.org/wiki/Binary_star#Configuration_of_the_system). That's because in general bright stars are young, dim ones are old (this is a very base supergeneralization), and if two stars close to each other have different ages, they most likely have formed in different zones and are probably not orbiting each other. For them to orbit each other the younger, most massive one should capture the older one, and such captures are more likely to happen at the galactic core (because you can't capture alone, you need a third body and that's where you find a lot of stars in close space) - where excess radiation is hazardous to life as we know it. So, if two stars are orbiting each other and one is much brighter than the other, they probably formed together and evolved to be like this:
The dimmer one in this case is the one to the right. The one to the left is colder, but its sheer size gives it more shining area, and therefore more luminosity.
This does not bode well for your planet. If it orbits in a plane that allows for an eclipse, it will cross the mass transfer stream when it forms. That will either decellerate the planet into crashing onto the smaller star, or fling it away from the binary. But not without causing it to be torn apart first. Not from the collision, but due to gravity!
In [your previous question](https://worldbuilding.stackexchange.com/q/152012/21222) about six-month periods of darkness, I gave you an answer which I think is far more feasible and which does not depend on a binary system. I think you should consider that one.
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[Question]
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Phytoplankton are not to be taken for granted. Not only do they form the core of marine food webs around the world, they also release half of the world's oxygen. But phytoplankton, being plant-like organisms, need nutrients for their blooms to survive and thrive into populations large enough to be visible from space. For many, the origins of those nutrients come from one of the least likely sources: desert dust storms swept up from far away by deserts. As the dust settles down to the oceans, they drop down enough nutrients to create these vast blooms on an annual basis.
**But what else could feed a plankton bloom on a global scale and an annual basis?**
You could say that volcanic ash could be the answer, but there's a problem--unlike dust storms, volcanoes don't erupt at once or regularly. Two eruptions from one same volcano could be years or even decades apart, and that sort of duration gap won't do for plankton blooms. So what ***else*** could feed a plankton bloom on a global scale and an annual basis?
EDIT--***NO*** manmade processes! Everyting MUST be natural!
[Answer]
**Rivers.**
[](https://i.stack.imgur.com/VA1hM.jpg)
<https://earthobservatory.nasa.gov/images/1257/mississippi-river-sediment-plume>
Depicted: the Mississippi dumping its load of sediment into the Gulf of Mexico. River flow is cyclical in most places, with high flow during rainy season or spring melt and low flow during dry season / winter or summer. During high flow, nutrients move from the land to the river and on to the sea. With the advent of synthetic fertilizer this can be too much of a good thing - so much nitrogen and phosphorus that they produce massive blooms, that then die.
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**Icebergs.**
Icebergs generation is periodic, both intrayear and over longer periods.
[](https://i.stack.imgur.com/EBgoq.jpg)
<https://www.nationalgeographic.org/media/iceberg-frequency/>
Icebergs that have scraped along the land can ferry nutrients out to sea, releasing them slowly as the ice melts.
[](https://i.stack.imgur.com/fhPdz.jpg)
<https://phys.org/news/2019-03-mystery-green-icebergs.html>
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> The green icebergs have been a curiosity to scientists for decades,
> but now glaciologists report in a new study that they suspect iron
> oxides in rock dust from Antarctica's mainland are turning some
> icebergs green... Iron is a key nutrient for phytoplankton,
> microscopic plants that form the base of the marine food web. But iron
> is scarce in many areas of the ocean.
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> If experiments prove the new theory right, it would mean green
> icebergs are ferrying precious iron from Antarctica's mainland to the
> open sea when they break off, providing this key nutrient to the
> organisms that support nearly all marine life.
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[Answer]
Eventually, phytoplankton don't really feed on dust, but on nitrogen (N), phosphorus (P), iron(Fe), and the various other nutrients plants need, that may compose it. But if a desert hold such nutrients, it will not stay a desert for long.
An example of a yearly massive bloom could be a mass migration of ground animal, on shore, for reproductive purpose (a bit like toad, that need water even if they are most the time ground animal). They will stay on the shore for some weeks, defecating and urinating, and releasing a massive dose of nitrates, phosphate and so on...
**Not accepted as an answer since last edit :**
Second example, industrial activity, mainly agriculture, may lead to algae bloom (like in Brittany, France, with the famous green and smelly algae). And since plants grow on yearly cycle, fertilizer are used on a yearly basis
[Answer]
Up-welling. Nutrients tend to sink to the bottom, or to deep water where not enough light reaches to keep photosynthetic life forms thriving. If there is some mechanism to vigorously return deep water to the surface then it can bring the nutrients with it.
<https://oceanservice.noaa.gov/facts/upwelling.html>
Up-welling might well be a seasonal thing. For example, currents could flow in one direction half the year when the snow melts in this hemisphere and builds up in the other. Then in the other direction for the other half of the year. This could produce a seasonal stirring of the deeper ocean layers.
Up-welling could be driven by temperature differences produced by geological heating that does not rise to the level of volcanoes. Water is at its highest density at close to 1.5°C. So if you have something that warms the depths it will bring the deep water back to the surface. This probably isn't seasonal.
In exotic places with exotic tides, that might do it. If a large moon had an exceedingly eccentric orbit, you could have extreme tides for the portion of the moon's orbit when it was closest, then far weaker tides the rest of the time.
Seasonal wind patterns might also do it. Wind tends to push the surface water along more than the deep water, so it tends to arrive at the surface near the down-wind land. Then it tends to sink and return to the depths. In reverse at the up-wind land, the water tends to get pushed away from the land on the surface, pulling the deep water up.
[Answer]
## Nothin but dust, baby.
Phytoplankton blooms are complex beasts. We've got a general idea of what causes them, and a general idea of what collapses them, but the intricacies are hard to capture. This is going to be a frame-challenge type answer; if you're not excited about those, you've been warned. If you're excited about the little green things, read on.
## Dust storms aren't regular, annual events
The question as asked conflates two phenomena connected to phytoplankton blooms - one, that blooms appear and decay with regularity; and two, that [blooms are sometimes caused](https://www.scientificamerican.com/gallery/saharan-dust-feeds-atlantic-ocean-plankton/) by [dust storms](https://www2.lbl.gov/Science-Articles/Archive/ESD-Gobi-plankton-Bishop.html). Both of these are well documented, but they're entirely separate events.
### Periodic blooms
Phytoplankton blooms have several regular, periodic cycles that they go through. These are best outlined by the recent review [here](https://royalsocietypublishing.org/doi/full/10.1098/rstb.2010.0125), but I'll do my best to summarize the process and explain why they've got a seasonal behavior.
These [little green things](https://en.wikipedia.org/wiki/Little_green_men) thrive on two things: nutrients and sunlight. In the ocean, sunlight is abundant right near the surface; but nutrients are more easily found at depth.
>
> Side comment: one other answer noted that "nutrients tend to sink", which isn't quite true. It certainly *looks* that way, if you look at [element profiles in the ocean](http://schooloftheabyss.blogspot.com/2012/06/periodic-table-of-ocean.html), especially for common nutrients like P, N, or Fe. However, these nutrients are instead found in low concentrations at the surface because they're all tied up in cell structures rather than dissolved in the water column. When dead organisms sink in the water column, those elements are [remineralized](https://en.wikipedia.org/wiki/Remineralisation) and returned to their dissolved form.
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Phytoplankton deal with this discrepancy by forming something known as the [Deep Chlorophyll Maximum (DCM)](https://en.wikipedia.org/wiki/Deep_chlorophyll_maximum) at a depth deep enough to have nutrients while avoiding missing out on the sunlight from above. When nutrients can be found closer to the surface, the phytoplankton also tend to get shallower.
So, seasonality. The ocean is normally thermally stratified - organized vertically by density - which makes it difficult for deep water (full of nutrients) and shallow water (full of sunlight) to mix. However, this stratification breaks down when the surface water is about the same temperature as the deeper water. This happens in the winter - check out the graphic below, from [this excellent website](https://serc.carleton.edu/eet/phytoplankton/primer.html):
[](https://i.stack.imgur.com/p0byq.jpg)
Of course, during the winter there's not a whole of sunlight - so when the sun comes back in the spring, we get a phytoplankton bloom that happens over an entire hemisphere! Check out the link [here](https://www.youtube.com/watch?v=EKwiXWMDen0) for an excellent animation from the NASA Earth Observatory demonstrating this. That's the main *annual* cycle.
In lakes, we often get two blooms - one in spring and one in fall. The logic above still applies, but in lakes we get reverse stratification in the winter that means that mixing happens more in spring and fall than in winter. A similar graphic [from Nat Geo](https://www.nationalgeographic.org/media/lake-turnover/) below explains this better:
[](https://i.stack.imgur.com/gJcxzm.jpg)
This means that lakes often have *semiannual* blooms, in both spring and fall.
### Irregular blooms
The final kind of blooms we get in the ocean aren't regular at all. That's because these blooms aren't triggered by any kind of seasonal or annual cycle (especially if we're not including fertilizer runoff in the growing season), but are instead triggered by random events such as dust storms, volcanoes, or rivers.
Dust storms are especially powerful fertilizers because the ocean as a whole isn't limited by a single nutrient. Some areas desperately need phosphorus and have nitrogen to spare, while other areas are [iron-limited but otherwise high-nutrient](https://en.wikipedia.org/wiki/High-nutrient,_low-chlorophyll_regions). The figure below summarizes this for diatoms, a major constituent of phytoplankton (from [this paper](https://www.sciencedirect.com/science/article/pii/S0967064501001096#FIG11)):
[](https://i.stack.imgur.com/CEPQg.jpg)
Dust is great because it's full of all these things! Most notably, the iron and phosphate nutrient cycles have **no** airborne component, meaning that you can't pull those nutrients out of thin air [like you can with nitrogen](https://en.wikipedia.org/wiki/Nitrogen_fixation#Endosymbiosis_in_diatoms). Dust is generally made of rocks (or, rocks are made of dust?), so this is one way to transport a whole lot of phosphate and iron into the surface ocean. Rather than rising up from the depths, it's being dropped from above. That makes it *really* hard to mimic, especially on a global scale.
## TL;DR:
Dust-triggered blooms are unique events. They're not periodic, but they are special because the transport nutrients that would normally be very hard to find in the middle of the ocean. Given that periodic blooms happen to at most a hemisphere at a time (i.e. not global), and that dust-triggered blooms aren't annual, a frame-challenge answer to this question is necessary.
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[Question]
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Consider a fantasy species of "natural" time travelers. To define some specifics:
**Relevant Rules**
* While it is not effortless, this species can move against the "arrow of time" much as a human can swim upstream a *gently* flowing river (and they don't need a machine to do so). The swimming metaphor continues: they can "speed up" (or "slow down") the process with effort, to a certain limit. They experience their own subjective time, and age accordingly.
* We have limited multiverse theory: Changes made in the past "fork" into new timelines. These timelines *do not exist* until created. Not all possibilities actually exist. It is also possible to move laterally from (existing) timeline to (existing) timeline, with some concept of 4D distance between them. To extend the swimming metaphor, they can get out of the water and walk to another stream, which also takes subjective time and effort.
* The species only has one point of real consciousness, or "existence"-- that is to say, they can't interact with their subjectively past selves. If they go back in time, their former double vanishes from the new fork. If they meet with a past version of a friend who is also a member of this species, that friend vanishes in the new fork. Of course, they *can* sync up if they like.
+ Non-members of the species still exist across the timelines at every point, and fork as needed.
+ *Technically*, it's not a *single* point, but a small "area" of time lasting a few moments, to allow things like seeing a friend moving backwards in time for a short duration before vanishing.
+ You can't really save a friend's life except within this tiny little window, because going outside the window will have the friend vanish from your perspective.
**Other Rules**
These are, in my mind, less relevant to my specific question, but since time travel is such a weird thing when you think about it, I may as well show you how I've hammered out other aspects for my story.
* They can drag a fuzzified amount of matter along with them, such as clothing, held objects, air, etc. They also push on matter in a 4D way. This is like making little eddies in the water, and avoids XKCD "[what If: Relatavistic Baseball](https://what-if.xkcd.com/1/)" effects.
+ This doesn't make an infinite number of forked timelines as they go back moment by moment, but will build up effects that influence the new timeline once the person starts going with the flow again.
* Changes to themselves persist. If shot with a gun, going back in time might see the bullet ejecting, but it's not going to heal them from the bullet wound.
* Their location, and forces acting on them at that location, stay intact (unless they're stepping outside the timeline... but they need to step back into a timeline to go backwards instead of laterally). Jump off a cliff and start going back in time mid fall, and you're just going to keep falling as you go back in time. You can see other people and things reversing as you fall, but you keep falling. No "[Prince of Persia: Sands of Time](https://en.wikipedia.org/wiki/Prince_of_Persia:_The_Sands_of_Time)" here.
**Question**
My question is: how could such a species have a meaningful society amongst themselves? Even with the restriction that timelines don't exist until created, it looks like they would have a problem of getting hopelessly separated from each other, eliminating any possibility of civilization. For that matter, it would make finding a mate nigh impossible, and since they aren't immortal that would mean the end of the species.
So how could this work?
[Answer]
Imagine this scenario: our group of friends decide to explore a complex and unending cave system. It's quite easy to get lost or separated, and not feasible to always stay in line-of-sight. How would we manage to stay connected?
We simply decide on a rendezvous point -- a safe base to return to after taking a jaunt through the caves. That way we can go off on adventures, but always come back to family.
At first, treks would be limited by our memory of the branches and our social needs. But over time, one rendezvous point would become many, spread out over the branches. we might develop technology like maps, compasses, and navigation apps to help us find our way. We might also make signal flares, radios, then texting and video chat to stay connected over longer distances. We might even invent cars and trains that move us through the branches with ease.
But some of our oldest cities would still survive. They were established with the limitations of older technology: centrally located among the branches, easily defensible from attack and not prone to disaster, yet near convenient outlets for transportation. Their wide but winding streets would follow the turns of the ancient branches they were founded on.
In short, your time travelers need a home.
[Answer]
Society form when its potential members need to act collectively to improve their circumstances and survival. You have identified the biggest problem experienced by your natural time-travellers. Namely, that a time-traveller will cause their own past self to disappear. Since this also applies to other persons close to themselves. For example, their friends and so presumably close relatives too. This will tend to cause any grouping of these time-travellers to be dispersed across a plenitude of divergent timelines.
Therefore, natural time-travellers will form a society based on behaviour and procedures that will restrict time-travel itself. Basically this is intended to prevent themselves becoming separated across the timelines. This could mean that a tribe of natural time-travellers will keep together almost all of the time. When they travel in time they will all travel together. This will mean no single natural time-traveller can slip back into the past alone. The objective is to prevent losing themselves and becoming separated.
Societies tend to develop rules and laws that are to their advantage. For example, the time-travelling society postulated by this answer will be able to protect itself from large-scale harm because they will all travel against the arrow of time together and reach a point in the past where they can take action to evade whatever the harm was. For example, a volcano erupts and a tribe of time-travellers goes back into the past far enough before the volcano erupts to be able to leave the vicinity and go to where they will safe from the volcano.
It may seem paradoxical from a society of natural time-travellers based on restricting or regulating their use of natural ability for time-travel. However, if such societies can use their time-travel abilities on a community basis this will confer enormous social advantage. This will eb the basis for a meaningful society for natural time-travellers.
[Answer]
Give them the instinctive ability to recognize each other's prime instances and to detect them across time and timelines. That way, when the nature of your world naturally separates them, they have the option of exerting themselves to reunite.
They would have strong motivation to both separate and reunite regularly, as their natural time travel capability allows each of them to undo any life-ending mistakes which their friends commit. When after exerting one's ability to re-synch with a loved one, one finds the loved one is now a corpse, all they have to do is swim upstream in this fatal time stream to a point where their friend is alive, so that together they can find/create a less tragic alternative time stream.
Similarly, they would have strong motivation to separate into distinct time streams regularly, so that at least one of them survives any dangerous moments.
A culture of such travelers would be complex and multi-layered, with a variety of fascinating distinctions, which are not available to us other species, who are impaled on Time's Arrow. Their history would be free to tragedy, with almost all mistakes from the past nullified from the perspective of the current moment. Their history in fact might look a lot like a Charley Chaplin or Buster Keaton movie, full of near catastrophes which miraculously work out okay.
Unfortunately, any current day adventures which you create with these creatures will also suffer from a guaranteed happy ending. As they now exist, your creatures are more powerful than you, their author. There is nothing you can plot into their creation which they cannot simply undo with a little effort.
You need to think hard and build a scenario which negates their advantage, so that at least the illusion of risk exists. Something for your reader to bite into. That is going to be the great challenge to using these characters in your writing, but if you can overcome it in some subtle and unexpected way... it will be marvelous!
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Give them the additional ability to merge timelines. If they can create a new split surely they can also splice a timeline together. This allows for them to reconnect and find other Travellers as well as introducing some new fun issues!
What happens if a Big Bad is defeated in one timeline but they accidentally merge with a timeline in which he is still alive? What happens to the inhabitants who know that a certain non-Traveller character died and merge with a timeline in which they are alive?
That gives some story leeway. It would also allow the Travellers to have a means to have a regularly scheduled meeting where they can merge timelines and reassert a "Main" timeline. Think of it like GitHub but for time travel!
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How can a species force an external body to heal itself and speed up the process without the use of magic and technology but by biological means?
Sanators are creatures who can force the body of a nearly dead person or animal to heal or stop bleeding, even on the edge of death or when they are unconscious. How can this be explained without the use of handwavium?
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They need several things.
1. A mix of useful chemicals. Clotting factors, cell growth promotors, antibiotics, key nutrients. This can stop immediate bleeding and help generally optimize the organism.
2. Advanced stem cells, which can mimic the cells of the organism they are healing. They need to inject this into the damaged tissue to quickly repair any holes.
3. Some sort of medical injection system to get their healing stuff into their target.
4. Medical knowledge of where injuries are and what to inject in what place.
So, perhaps all of those factors could be in their saliva or claws, and when they scratch or bite someone, they heal faster? Along with a powerful sense of smell and excellent vision to diagnose where injuries are.
To handle the different species issue, they could have genetic splicers which analyzed cells and produced enzymes and hormones specific to each organism. To handle the evolution of bacteria and viruses issues, they could have a symbiotic relationship with fungi that produced novel antibiotics and chemicals to inhibit growth of rival organisms. Evolutionarily, these creatures would have evolved symbiotic relationships with a variety of organisms, using them as ways to replicate themselves. Like a virus they would take over other organism's cells, and use them to fill gaps and holes, and keep them alive.
You could have conflict and issues over this specificity, with some individuals being unable to heal certain species or races because of how their systems were adapted, or some species being too hard for their biological systems to interpret.
Very alien biologies would generally be impossible to fix with these.
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Your Sanators have an ability like [SOME SPECIES OF WASPS](https://en.wikipedia.org/wiki/Emerald_cockroach_wasp) that can slow the metabolism of their prey through the injection of toxins.
However, your Sanators have learned to use this to help in healing as well. When a creature near death is stung, their metabolism slows to nearly nothing. At this point, a second injection inserts intelligent stem-cell like cells into the victim that read the DNA, and begin to repair the organism. Your Sanators could also wrap their patients in a cocoon like shroud that would help accelerate the healing.
This could also be used as a plot device to have your peaceful Sanators mistaken for predators while they were actually healing people.
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It is most certainly possible to perform miraculous healing biologically, but it would probably not be as life-saving as you were envisioning.
The reason why it takes so long for an organism to heal itself is because of natural blocks on how often a cell can undergo mitosis to repair any missing or damaged cells. These natural blocks are a part of the organism's DNA and help to prevent many dangerous situations that may arise from uninhibited cell growth, including artery collapse, a loss of muscle function, and even starvation. Without these, however, the body can heal itself at an incredible rate, quickly replacing any missing cells as needed.
Even if your Sanators were able to target these DNA blocks with an extremely precise burst of radiation to enable rapid growth, there would still be the issue of stopping the growth before it eventually kills the organism. Since every cell produced via mitosis would be almost an exact copy of the original cell, they couldn't simply remove the altered cells, as that would undo all the work the body had done up to that point. The only way I can think of that would work would be to reverse the alteration in every single strand of DNA that was replicated, but it would require an insane amount of energy and precision to be able to pull off on the thousands or tens of thousands of cells needed to fix the problem.
Oh, and in order to pull this off, the Sanators would need to disable at least part of the organism's nervous system so it wouldn't destroy the altered cells before they spread, so it is possible they may die of their ailment anyways...
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Few problems to biological healing :
* You need the resources to replace or repair what was hurt.
* You need time for cells to replicate enough to replace or repair what was hurt.
Without any kind of cheating, you can't make the time go faster or make resources magically appear in the body of the anyone near.
But, what could be somewhat credible with still a bit of handwavium :
Your Sanators are somehow constantly emitting a cloud of **UBERCELLS** around them. These **UBERCELLS** have three particularities :
* They will naturally copy the genome of first nearest cell they meet (maybe by eating it, first) which is not a **UBERCELL**.
* They have a very fast reproduction rate.
* They are very big. Which mean they can replicate to a thousands smaller cells without breaking a sweat before lacking resources.
So what you obtain is what could be parent to a "stem cell spray".
Stem cells are (real) non-differentiated cells than can differentiate into every possible cells of an individual (they are the kind you find in an embryo) and are presently being researched and used to grow tissues for transplant or even fight some sicknesses. (Awesome stuff, really).
Stem cells would probably die if you directly sprayed them on an injury but **UBERCELLS** don't. Because they are very strong and hardworking, they just pick up the job of the closest cells and help them during the healing process. Which is exactly what you are looking for.
*Disclaimer :
The Sanator decline any responsibility concerning the following :*
*- In case of infection by a virus of the host, the **UBERCELL** may occasionnaly hasten death.*
*- If the **UBERCELLS** come into contact with a cancerous cell, the host won't like it either.*
EDIT : **UBERCELLS** only work on eucaryotes, aka cells with nucleus. Which prevent any kind of bacterial disaster.
[Answer]
[Traditional Chinese Medicine](https://www.actcm.edu/chinese-medicine/) works with chi (often spelled qi) (a real thing that Western Science can't really explain very well) to help the body heal itself.
While this usually happens with the use of acupuncture needles or other direct stimulation to the points and channels (acupressure, massage, electrical stimulation, heat, etc), or with herbs/diet, there also exists energy work that a practitioner uses, with or without touch, to effect changes. The one I was personally trained is is called [HoChi](http://hochi.org/) and is a form of Chi Gong. But there are others. (Note: it's the same teacher but the website doesn't have the same focus on medical healing I had and sounds more New Agey now, even though it's a very old modality).
As wonderful as TCM is, it's not magic and it won't solve all problems. In China all the hospitals are half TCM and half Western Medicine. Because different ailments require different treatments. Sometimes you really do need surgery or pharmaceuticals. But all the staff are trained in both modalities so they work together very effectively.
Obviously what you're asking for doesn't exist in the real world, or people would be doing it. But it would be reasonable to take a system like TCM and amp it up. Give your Sanators so much control over chi that they can make it seem like magic. And allow them to channel universal chi to boost that of others (something that practitioners can do now but only in very small amounts).
This is not a perfect answer because you seem to be asking for science that shows this miraculous healing. No one can give you that because it doesn't exist. But this is the closest I can come. TCM or similar systems from other countries.
Edited to add in some research links on TCM, as requested. Some talk about the need for better research studies and some quote skeptics. Some just present the research.
* [National Center for Complementary and Integrative Health](https://nccih.nih.gov/health/chinesemed) (NCCIH) (part of the U.S. Department of Health & Human Services). Also an [article on acupuncture](https://nccih.nih.gov/health/acupuncture/introduction).
* [Cancer Research UK](https://www.cancerresearchuk.org/about-cancer/cancer-in-general/treatment/complementary-alternative-therapies/individual-therapies/traditional-chinese-medicine).
* [Pubmed search #1](https://www.ncbi.nlm.nih.gov/pubmed?term=%22Medicine%2C%20Chinese%20Traditional%22%5BMesh%5D%20OR%20%22Drugs%2C%20Chinese%20Herbal%22%5BMesh%5D%20AND%20%22humans%22[MeSH%20Terms]%20AND%20English[lang]%20AND%20Randomized%20Controlled%20Trial[ptyp]%20AND%20%222014/01/08%22[PDAT]%20%3A%20%222019/01/08%22[PDAT]&cmd=DetailsSearch) — [Pubmed search #2](https://www.ncbi.nlm.nih.gov/pubmed?term=%22Medicine%2C%20Chinese%20Traditional%22%5BMesh%5D%20OR%20%22Drugs%2C%20Chinese%20Herbal%22%5BMesh%5D%20AND%20%28%22humans%22[MeSH%20Terms]%20AND%20%28Meta-Analysis[ptyp]%20OR%20Review[ptyp]%29%20OR%20systematic[sb]%20AND%20English[lang]%20AND%20%222014/01/08%22[PDAT]%20%3A%20%222019/01/08%22[PDAT]%29&cmd=DetailsSearch)
* [Research Capacity at Traditional Chinese Medicine (TCM) Centers in China](https://www.hindawi.com/journals/ecam/2017/4231680/): A Survey of Clinical Investigators, Evidence-Based Complementary and Alternative Medicine, Volume 2017.
* [Nature. Why Chinese medicine is heading for clinics around the world](https://www.nature.com/articles/d41586-018-06782-7):
For the first time, the World Health Organization will recognize traditional medicine in its influential global medical compendium.
* [Research Finds Acupuncture Effective for Chronic Pain.](https://www.aafp.org/news/health-of-the-public/20180521acupuncture.html) American Academy of Family Physicians.
* MedlinePlus, U.S. National Library of Medicine, U.S. Department of Health and Human Services. [Acupuncture](https://medlineplus.gov/acupuncture.html).
* [Mayo Clinic research on acupuncture](https://www.mayo.edu/research/centers-programs/integrative-medicine-health-research/research-studies/acupuncture-studies).
* [Society for Acupuncture Research](https://www.acupunctureresearch.org/).
[Answer]
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> Sanators are creatures who can force the body of a nearly dead person or animal to (...) stop bleeding.
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Sanators are army ants. You can get them to bite both sides of a wound, then chop off them buggers' heads. You get instant sultures without having to know how to sew.
[I'm really serious](https://ideas.ted.com/a-history-of-biomaterials/). Try not to scratch the wound though, and I hope you are not alergic to ant bites.
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[Question]
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I've already considered that they may file their horns down, but keeping in mind that their horns gradually regrow, it is an inconvenient solution.
This is what their horns typically look like:
[](https://i.stack.imgur.com/uUGYm.jpg)
They do have very strong neck muscles, but I don't want the helmet to be overly cumbersome.
I'm open to other solutions that circumvent a helmet, too, but still fill the required needs, which are:
* Allows the alien to breathe in space or on inhospitable planets
* Keeps their head at the correct pressure in low and high pressure environments
* Protects the head from radiation, heat and cold
* Protects the eyes from intense light
Details about the horns:
* Their horns have no blood supply or nerves except at the base; the base of the horn is responsible for regrowing, repairing, and shedding the horn.
* They can withstand large temperature ranges (albiet less so in the cold margins) provided that the transition is slow, otherwise the horns will fracture.
* If exposed to sand storms or very acidic environments, the horns will wear down rapidly or in the latter case, decompose.
* When the horn is regrowing, a velvet like sheath with a blood supply conceales it. If this blood supply is completely constricted, the growing horn will die and fall off. If not enough blood is allowed, the horn will be bendy, like cartilage, and grow at a reduced rate.
* The horns regrow from the base, not the tip. They are triggered to fall off entirely when a high margin of damage has been accumulated. (Assume they have an innate way of detecting this without pain-triggering nerves, like how a tree can regrow from being cut down, or how plants have measures of repairing themselves when injured without feeling pain)
The technology that they have available to them is equal to what you can expect from space-fairing human technology, as they were uplifted by humans at their equivalent of the Bronze Age. Assume this technology is advanced enough to make self sustaining migrant ships to traverse the Milky Way, but not advanced enough to travel near lightspeed, nor resourceful enough to entirely colonize barren, unsustaining planets.
[Answer]
## Standard sleeves that glue over your horns
Since the horns are not damaged by the vacuum of space, you simply put a semi-permanent sleeve on them at the appropriate location. The sleeves are made in a variety of sizes, but all have a common outside diameter. They have a polished, hardened surface with a locking ring.
When donning the suit, you thread your horns through the standard sized holes, which lock into the standard sleeve.
Epoxy would fill the gap between the manufactured piece and the particular form of your horns. A formulation of epoxy would be used that is vulnerable to being dissolved by a particular chemical unlikely to be found in regular operations. Or a coating of cyanoacrylate would be laid down first. That is dissolvable by acetone, unlike epoxy.
Astronauts would typically have these installed as they elevate in the space program to where they would be fitted for a suit. They could have them removed when the government said "you are done with space travel for awhile".
Lots of men who were not actually in the space program would get them to impress the ladies.
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I dont see much of a problem?
This is the helmet NASA made: <https://www.nasa.gov/images/content/345643main_grunsfeld-m_946-710.jpg>
It fits over the head and locks down on a ring on the suit. Looking at the rest of the suit, you can see that the hands for instance dont have a full "skeleton" around them to keep it pressurized. And the helmet of your horned space faring aliens will be able to do similar things.
Make the helmet in two or three parts (or more if theres more horns). First you put a space-suit like material over the horns like the one's around the hands, with nice padding to keep warm. With a locking ring similar to the one around the neck at the base of the horn material. You lock together the Rings around each horn with the front and back piece(s) of the helmet, creating a seal around both the horn openings and the neck. Done!
[Answer]
Basically it all just comes down to size:
Easy as pi with Acme Space Division's *Helm360*, which offers basic functionality in an astounding range of bowl and neck sizes:
[](https://i.stack.imgur.com/HJUXL.jpg)
We also offer our *Inalienable-2500*, a line of comfortable bespoke helmets, suitable for our extraterrestrial customers with difficult to manage appendages or anatomy:
[](https://i.stack.imgur.com/oIpra.jpg)
If your Star Armada is currently experiencing Imperial budgetary cuts and you're looking for a more economical but still smart design, try our Tholium-1000 line! Comes in a variety of neck openings and the cranio-vault can be expanded with our patented inflation technology to accommodate a large number of diverse crew members:
[](https://i.stack.imgur.com/2Pcds.jpg)
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**One time use custom instant helmets.**
Your horned folks are probably going to have all kinds of different length, shape and number of horns. They will need custom helmets.
I propose they could apply the helmets as expanding foam, or something like shrink wrap. It would cover irregular horns and faces and then rapidly harden or stiffen as appropriate. The film / foam would be applied directly onto the wearer, with the face/plate and respiratory apparatus as a framework already on.
The result would be a helmet which recognizably has the horn structure of the individual wearer, which is the dream we all dream of.
Removing the helmet would mean destroying it, or at least the film / foam component. It would break away. Perhaps these materials would be recyclable or maybe thrown out. I have to think the face plate and attachment framework would be reused, and not be specific to an individual head shape.
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I don't get why you're so worried about *cumbersome* unless you were thinking the helmet had to be a sphere.
Think of the horns as structural members, maybe supporting a heat radiator panel between them. They don't need a lot of space around them so an flexible sleeve would work quite well. It could be made with nested semi-rigid sections like the collapsible bowl or cup sets used by campers.
[](https://i.stack.imgur.com/4OZ1E.png)
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[Question]
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> *TL;DR - I want my angelic race to have the ability to speak in a way in which up to three sentences are communicated at the same time. (Assume English for the sake of simplicity. I want physiology answers, not conlang answers, as evidenced by the question on whole and my tags.)*
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In my story, angels have the ability to express 3 sentences at the same time. If I were to write this out, it'd be a matter of [Main sentence], [Supertext], and [Subtext] all being in line with one another (like furigana in Japanese in terms of writing, but I know that's not how it works when spoken). These three sentences would be restricted to the same topic, but might be along different expressed ideas with the Main Sentence being the critical information and the Supertext/Subtext adding details to the sentence. For example:
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> The dog has brown fur.
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> The dog ran away.
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> The dog was barking.
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In English, we'd simply say "The brown dog ran away while barking."
(And because I know somebody would ask "Why not just use English then?") Alternatively, using a more "high school" example:
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> Did you see what she was wearing?!
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> Jenny is such a b-.
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> She's totally sleeping with Mr. Caulton.
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In this example, the person would be expressing three sentences all about how much they dislike "Jenny", but the three thoughts aren't all describing Jenny directly. Aside from making a paragraph saying these things (or a LONG compound sentence), English doesn't really have a way of properly expressing this. In the angelic tongue, this would be nicely condensed, though.
Now, I know asking for details on writing the language would more be a matter for the Conlang SE (maybe), but what I am curious about is this: What would be necessary for not only an angel to say these three sentences at once, but for somebody to be capable of understanding them clearly?
MAKING IT A SINGLE QUESTION: What would be the necessary requirements for this kind of speech to be communicated effectively?
I'll accept whichever answer is the simplest, but most effective. My current process involves manipulation of polyphonic vocalization, but I feel like there has to be a better way. I want my angels to still pass for being aesthetically human. They can't be distinctly alien in appearance to make this work. It needs to be up to 3 separate sentences spoken at the same time, but needs to also allow for only one or only two sentences as well. (Meaning, just because they can speak three sentences at once, that doesn't mean they are physically required to. It should be something they can control.)
To answer questions:
- I need it to be a single mouth if at all possible. If there HAVE to be multiple mouths, I could always give the angels an inherent glamour effect, but would prefer to minimize the amount of magic used to keep them looking human.
- The voices can be somewhat differently pitched, but preferably not in a way where one sounds like Crocodile Dundy and the other like Mickey Mouse (and the third like it's coming straight from the depths of hell). I'd prefer if they were all "normal" voices, even if one is higher pitched and another lower.
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Angels are clearly part bird. More specifically, they have a [syrinx](https://en.wikipedia.org/wiki/Syrinx_(bird_anatomy)) instead of a set of mammalian vocal cords. As a result, they can effectively produce two different sets of tones at the same time by controlling the air flow in and out of each lung.
More exotically, you could bring their trachea further up into their chest and give them a "fake mouth" for each tube - that way, they could produce multiple labials and fricatives in parallel, coming from deep inside their (broader than a human's) chests. You should be able to get three vocalizations in parallel with this arrangement.
As for understanding them... it'd probably take specialized training to parse out individual sentences - ever try to listen to pay attention to multiple people speaking at once? -
but it should be just dandy for making them sound all echo-y and choral.
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> This answer was to an earlier version of the question before I understood what Sora was looking for. Please do not vote for it. It is retained only as a reference. Thanks.
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**Recognize that you'll have limits. You won't be able to arbitrarily express any three ideas, even if related**
What you have to work with falls into several categories.
**Spoken Inflection** How you express a single word can express additional context. We actually do this already. Even with a simple word like "no," the vocal intonation can express humor, incredulity, definitiveness, alarm, etc. Curiously, Engligh-speaking humans have never codified this behavior to produce more efficient language — but that might be because expressing it in written form (through the use of diacritics) makes the written language much more complex.
**Expanded Conjugation and Declination** Other languages (e.g., Finnish, which I speak (well, not as well as I did 30 years ago)) use complex conjugation and declination combined with suffixes to substantially modify the base meanings of words. This process would, for example, convert the verb "to jump" to the noun "one who jumps" to the verb "to be one who jumps" to the adjective "of the nature of being one who jumps," etc. Friends and I once tried to calculate the number of legitimate words with unique meanings based on the ways words could be conjugated, declined, and modified with suffixes. We stopped counting at 250,000 and moved on to something else.
**Secondary Vocalization** Have you ever heard someone speak or sing in two tones at once? I have. It's called *[polyphonic](https://www.youtube.com/watch?v=vC9Qh709gas)* and could be used to literally carry two levels of meaning simultaneously. For example, if we use only the word "no" as an example and the handful of intonations mentioned above, you could express 4\*3=12 possible unique meaning combinations at one time. You could really run with this one, angels being what they are, they could have as many vocalizations as you want. Give them four and you have (per my example) 4\*3\*2\*1 = 24 unique meanings at one time. (That mathmatical progression is called a *factorial* or n! meanings for every "n" vocalizations.)
Those three examples are purely vocal. If you include non-vocal possibilities such as body language or telepathy, your abilities improve considerably.
Where you have limitations is that, theoretically, none of the examples above can give you *infinite* expression. In other words, unless divine ability exists, the angles can do something unbelievably amazing, but not miraculously godlike. For most stories, such limitations are usually good things as they make the "superpower" more relatable to the reader.
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**You want music.**
I can sing you a song. I am conveying two messages when I do that - the melody of the song, which carries information in the form of pitch, key, transition and tempo. And you hear my words, the meaning of which changes because of the music that is with them. I can sing to you and play my guitar at the same time. I am conveying three messages when I do that: the song as above and the harmony of the guitar, which frames the message in the song and might itself become the message. I can tap my foot for #4. #5: I can move my body, sway and close my eyes, or glare and furrow my brow as I sing - all messages, all conveying information.
That is 5 messages and I am just a guitar player hoping for a coin in my case. Your angels are musicians par excellence. 5 messages would be beginners stuff to them.
[Answer]
These angels have much more control over their vocal chords than we do. They are able to create arbitrary sound waves using their voice boxes, much like a speaker, by adding together sound waves. Their auditory processing centers are also specialized to be able to separate out distinct sentences from complicated waves. Essentially, they are able to perform complex [Fourier Analyses](https://en.wikipedia.org/wiki/Fourier_analysis). This would result in some rather interesting abilities, from a human perspective. Like the ability to simultaneously enjoy three separate podcasts at once. They would likely be extraordinarily talented musicians and vocalists, because of the increased vocal and sound processing abilities. They can literally speak three sentences at once, because they can produce the necessary wave forms, just as any old speaker can reproduce three sentences simultaneously, and their highly adept acoustic processing brains can separate and interpret those multiple sentences at once.
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[Question]
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In this world, witchcraft is practiced openly and is respected. It exists in three forms: ritual and arcane. Ritual magic involves using the mana of the world and directing it in a way to suit you (altering terrain, changing the weather, erecting barriers, etc). It requires chanting, numerous ingredients, and a group of people depending on the spell. Although powerful, it takes a long time, and is only active for as long as the spell is performed. When the spell stops, the magic ends.
The second type, arcane, requires the use of your own mana to perform spells. This is the fireball, lightning wielding type that is geared towards attacking. It is simpler and faster than ritual magic. However, it is difficult to control and dangerous to use. More powerful spells require large amounts of mana, and a person can maim or kill themselves if they aren't careful.
The third type is rune magic, which involves giving magical properties to inanimate objects. All runes must be of a certain size depending on purpose, and work with some objects better than others. Some objects can be combined to form new materials, or given properties that would be unnatural for it. Runes are not permanent and must be re-applied periodically.
Witchcraft in this world is exclusive to females, but I want males to be important to this system in some way in order to make it more balanced. How can I go about doing this?
[Answer]
As I understand the world, it's basically women can use magic and men can't. How can men still be useful? Ideas follow:
**Teamwork**
Let's think about some real world teams. For examples snipers work with a shooter and a spotter. The witch is the shooter, but the man acts as the spotter. He can't cast the spell but he acts as the human equivalent of a targeting computer and is thus critical to delivering fireballs and lightening bolts to their targets.
Another example is craftsman. The men can't wield magic, but can learn enough nonmagical skills to be essential to rituals or runes.
**Offense/Defense**
There is the classic D&D example where the female is the physically weak magic user and the man is the meat shield (fighter or paladin class) to keep the witch from getting killed.
Another idea, men have counter magic. Witches have magic, but only men can use counterspells or cast defense shields. They may have to draw on the witch's power to pull this off, but it would make the presence of men in combat critical. Maybe rituals attract the attention of demons or ghosts and only men can create shields to cloak the ritual for hostile entities.
**Magic makes men awesome**
The average Joe is basically useless. But when a witch pumps magic into him, he gets new abilities. Sky's the limit here - super strength, precognition, healing, illusions, whatever. The key is that only men can do this, but only when empowered by a witch.
**Random thoughts**
Men as mana batteries. Men can gather and/or store crazy amounts of mana, which can then be transferred to the witch for use in spells.
Men soak magic backlash. Witches keep men around to soak negative effects of magic. Depending on how dark you want your story to be, this could lead to death and disfigurement easily.
Men as spell components. Men are needed to perform spells. How they contribute exactly is up to you. Just standing around looking cool? Meditation and concentration? Blood or physical matter needed? Sex magic? Straight up human sacrifice for every high level spell?
Women are not creative. Women are basically really good technicians. They learn and execute magic without issue. But for some reason, they can't creatively think about or interpret magic. Only men can do that. Which means that men must study magic, understand it, train the witches, and are the only source of new spells in the world. Lots of questions about why this is so - maybe some ancient god purposely separated these two things. Or it's the result of a disastrous worldwide magic accident.
Only men can do one of the three types of magic. Self explanatory, some type of magic is completely closed off to women.
Lock and key. Men release the restraints on women so they can use magic. Maybe this has to happen every time, every x years, or just once in a witches life. Might require physical contact or some kind of ritual, or something else (marriage?, human sacrifice?). The man should get something from doing this, like money or immunity to the witches magic. Maybe the inner strength of the man dictates how much power the witch can use. So there are men capable of releasing incredibly powerful witches and they are in high demand.
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In Robert Jordan's **Wheel of Time**, women were limited to groups of thirteen when doing magic together. However, if men and women mixed, they could join in much larger groups (13\*13=169 maybe?). There, both sexes could do magic, but you could change it so that men might only need to be there. You could make men a requirement for any group, possibly in equal numbers with the women.
In Laura Anne Gilman's [**Retriever**](http://urbanfantasy.wikia.com/wiki/Retrievers_series) series, demons can be used as familiars. This both makes the magic safer, as the demons keep the magic-users from overdoing things and burning themselves out, and it allows for more powerful magic to be done, as the demons can act as a sort of battery. Replace demons with men in your world. This could be important both with arcane and ritual magic. More power is generally useful. More control/safer may be useful with arcane.
In Jacqueline Lichtenberg's **[Sime—Gen Universe](https://en.wikipedia.org/wiki/Sime~Gen_Universe)**, Simes could take energy from Gens and do stuff with it. In your universe, you might change this to women taking energy from men. So only women could use magic, but they need men to get the power for it.
You might also consider allowing witches to put runes on men but not women (in addition to or instead of inanimate objects; adding would allow for some jokes about inanimate men). So men could do things that women could not. But of course a man needs a good woman behind him to allow him to do those things.
Another possibility is that men might be immune to magic. This takes them from punching bags to agents of change in their own right.
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1. Some rituals involve **sex magic** or tantric sex. If the witch leading the ritual is heterosexual, she'll need a man to have sex with. This might be especially important in any ritual about fertility, growth or creation.
2. You can use people as 'batteries' to draw mana from and men happen to be easier to tap into than women, or **men have more mana**. Possibly this only applies to certain categories of men: guys who've sworn a vow of celibacy; warriors; fathers; identical twins.
3. One of your ingredients is **fresh male blood** (willingly sacrificed) so you need a man to jab his finger with a needle and shed 7 drops of blood into the sacred flame.
4. **Singing** is important in the ritual and the more extensive your range of voices in your choir the better your spell will be. So you want some male bass, baritone and tenor voices to go with your female sopranos and contraltos.
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Perhaps males could act as the conduit or amplifier for magic, as a conductor rather than a source. They could help direct the magic and make it easier to use, or maybe even store it like a kind of rechargeable battery companion? If the magic is as dangerous to use as you say, they could be invaluable to any respectable magician who wants to keep themselves from harm or make sure their spells are perfect.
Another idea could be to have them be something completely different, like beast tamers or people who can speak to elements/spirits. Basically some other kind of magical guild that does not rely on direct witchcraft.
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The easy answer to this is to go hard on the traditional Chinese concepts around Yin and Yang. This would primarily fall into the Arcane category you described.
If it were me, I'd describe a scenario where destructive applications of Arcane magic require an almost irrational level of self-confidence and commitment which tends to come easily to men in any social culture resembling our own, but to which women are generally too self-aware and rational to achieve.
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Perhaps females are the only ones who can use personal mana for arcane magic, but males are the ones who have mana in significant quantity, which can be used with consent, or by more nefarious witches, without?
By the way, you should edit the question.
"It exists in two forms: ritual and arcane"
then
"The third type is rune magic"
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**Witchcraft can only be performed by an order given to the witches by a man.** The more powerful this "commander" ability is, the harder it is for witches to ignore.
The commanders can be a particular group of men (e.g. royalty or mysteriously chosen guys who'll become royalty when their commander ability is discovered).
This sets you up for an aristocracy where men supposedly rule, but only through their ability to command women. In other words - the commanders' true power is the power of their subjects, and the power of the subject is derived from the authority of the wielder.
Power struggles ensues, peppered with sexual/romantic affairs, along with discussions into equality and freedom. It's a best seller already :-)
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I have a world with 4 colossal cities. Like, more area than the earth big. They are inhabited by a population orders of magnitude greater than ours, consisting of many different species.
Due to the immense size of each city, each has multiple systems of government, the laws of which apply to individuals and their properties rather than a region. In interaction between governments, it is only legal if it is legal by all parties involved.
E.g. In a monarchy possession of a firearm is illegal. If someone in the monarchy had a gun, they would be arrested by monarchy guards. In a republic it isn't illegal to have a gun. If a republican had a gun on monarchist property, the gun would not be confiscated provided it remained holstered and was not hidden. If a monarchist had a gun on republican property they would be arrested and the gun would be returned, destroyed, or given to the owner of the property.
I came up with this system to deal with problems that would arise from forcing a specific set of laws on multiple species that aren't compatible. There is a rather intense story behind the systems formation involving laws like the age of consent being too high for certain species(you can probably tell where that goes).
Are there any major problems that could come from a system like this?
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There are several problems with this approach, some minor, some quite major:
## Who is bound by which laws?
If every citizen can choose one of 4 systems of government, regardless of their own age, species, appearance and whatnot, you cannot know who has to abide to which laws.
If someone with a holstered gun stands before you, you cannot know if it's a republican acting legally or a monarchist breaking his laws.
## Why shouln't I do what he does?
Imagine you see some people wearing unobscured guns around like other people wear hats. Why shouldn't *you* wear a gun as well? To hell with stupid laws, if *they* are allowed to wear guns, it cannot be too bad, right?
The same principle applies to basicly any other prohibition that other people can simply ignore. Especially combined with the fact that you cannot see who is bound by which laws, people will inadvertantly and deliberately break the laws they personally deem useless.
## Exploiting laws inappropriate for my species
If the age of consent in one system of government is 5 years old (due to shorter lifespan of one specific species), but I register my "adopted" (or abducted) human daughter under this system and sell her as prostitute, it will be legal.
If alcohol is addictive to humans and therefore prohibited in one government but legal in another, I can simply change my system of government and legaly drink alcohol.
## Massive Loopholes
>
> the gun would not be confiscated provided it remained holstered and was not hidden.
>
>
>
This allows for massive exploits in the lines of "It wasn't murder, it was self defence" or "She said no but meant yes".
* Who monitors when a weapon is drawn?
* At what specific point is a weapon drawn? At 10% or half way out of the holster?
* What counts as hiding a weapon? If the wind blows my cloak over the weapon, am I a criminal?
* Are there objective proofs whether a weapon was hidden or drawn or not?
## Claim of ownership
>
> If a monarchist had a gun on republican property they would be arrested and the gun would be returned, destroyed, or given to the owner of the property.
>
>
>
Just because an object becomes criminal on my property, I still have no claim of ownership over the item.
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# Would you believe this has been done before?
Back in the days of theocratic monarchies, the law of the land wasn't particularly strong compared to the law of the church. The law of the church required attendance at church, appropriate behaviours during festivals, days of rest etc along side the usual thou shalt not kill type rules which were enforced by the state.
This lead to certain problems, half the enforceable religious rules of Christian countries didn't apply to other groups, e.g. Jews, that puts them outside the system and in turn somewhat outside society, and we all know how that ended.
You're going to see discrimination, you're probably going to see factionalisation, you could even see pogroms.
What's going to be more interesting is the [indirect discrimination](https://www.citizensadvice.org.uk/law-and-courts/discrimination/what-are-the-different-types-of-discrimination/indirect-discrimination/). One group must wear hats, one group may not wear hats. Hats aren't permitted in this building, you must take your hat off to enter. Of course doing so breaks your rules, but that's your problem not mine. No hats in here.
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## Class Separation by Law
In a faction system like this one, many issues would be rooted within the main one; segregation.
Throughout their lives some people will have the advantage over others.
With individual laws some factions will end up progressing at a much faster rate than others will.
Over time they will become the ruling class within your society.
If it works like citizenship then people will try to migrate to whichever faction best suits their beliefs. While some may be rejected, each faction will take the best they can from all applicants.
This, coupled with the fact that some factions will undoubtedly have more popular laws, means that some factions will be dominate.
Over time, I can foresee maybe a couple of factions gaining all the power politically and otherwise running the whole mega city.
While the rest are pushed to one side, some may be able to strike a deal when they figure out that they have a very particular skill, that can be used by the upper factions.
As such they would be somewhat supported, but still under the thumb of the upper factions.
I can also imagine one or maybe two classes becoming the runt of the city.
The one thing all other factions can agree on is at least they are superior to the runts...
Also with enough differences in weapon laws there will be a lot of calls for banning certain weapons in certain parts of the city.
Enough incidents to do with gun crime in a majority non-gun carrying part of the city could splinter the city into almost different countries, with very distinct borders.
I am by no means against this idea as this sort of dystopian future system has been and can be written with very interesting story behind it!
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As your Question is quite broad my answer will specificly tackle the "Big picture and the possible conflicts between factions"
I can see 2 scenarios. (+1 not involving your example of firearms)
1: Possible Civil War
-The population is foremost divided by Ideological differences moreso than species specific policies.
-Believing their way of life is superior the lines between factions will be very deep and a great deal of conflict will arise, build up, spark unrest and may even result in open conflict. Alternatively factions might fall behind in the everpresent competition with the others and as a result be swallowed by the remaining ones.
-referencing capitalism vs communism in the Cold war.
2: Totalitarian Control of Population.
-The laws might drasticly differ in personal freedom and Goverment involvement (Monarchy/Democracy) to the point it overshadows species preferences.
-The communites with most personal freedom will be the more disireble even if species specific laws are not optimal and a general migration of labour towards personal freedom will leave Oppressive Communities with too few high skilled workers.
-referencing the GDR/FRG Border conflict
3: Strict segregation with very few interspecies exchange between factions.
-The defferences in laws will nearly all be related to the defference in species.
-Therefore it is undisireble to be subject to the law of a different species than one self.
-But if one Population reaches its maximal expansion confined by their habitat, they will likely try to subjugate another people to take theirs.
All 3 will involve strict Border Control to prevent invasion, mass migration or both.
The problem is that treating people occupying the same space differently will inevitable lead to conflict wich leads to hate. It instills an us vs them mentality.
One Solution would be a Totalitarian (it would have to be quite oppressive) Planet state that enforces peace.
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**Law enforcement specific to residency status is done routinely in the US and elsewhere.**
You can have a stable, normal system with laws that apply differently to different individuals. Consider firearms. US citizens have a right to own firearms. But if you are an alien resident of the US you do not have this blanket right.
<https://www.atf.gov/firearms/qa/may-nonimmigrant-alien-who-has-been-admitted-united-states-under-nonimmigrant-visa>
May a nonimmigrant alien who has been admitted to the United States under a nonimmigrant visa possess a firearm or ammunition in the United States?
>
> An alien admitted to the United States under a nonimmigrant visa is
> prohibited from shipping, transporting, receiving, or possessing a
> firearm or ammunition unless the alien falls within one of the
> exceptions provided in 18 U.S.C. 922(y)(2), such as: a valid hunting
> license or permit, admitted for lawful hunting or sporting purposes,
> certain official representatives of a foreign government, or a foreign
> law enforcement officer of a friendly foreign government entering the
> United States on official law enforcement business.
>
>
>
Except some aliens can have a gun - as noted in the exceptions. And some citizens cannot - for example if I have a criminal record precluding gun ownership.
So too in your system. A monarchist in republican territory would be like a legal alien in American territory. If the monarchist had a gun it would be confiscated according to the republican laws governing monarchists unless the monarchist was a law enforcement office on official business etc. Perhaps an Anarchist visiting republican territory would not be allowed to have a firearm under any circumstances.
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The biggest issue with such systems is that they do not provide the stability we typically seek from legal systems. Accordingly I would expect the set of laws accepted by all such groups to handle the vast majority of day to day cases.
The purpose of laws is to provide either a codified document of what is right and what is wrong, or a codified document of causes and effects, depending on how cynical you are. It is designed so that the rules are known ahead of time. You *know* that if someone steals your wallet on the street, there is a system of justice which will seek out the thief and run them through a particular set of rituals, and possibly do something like incarcerate them.
Now it's obviously more complicated. We don't know all the laws and their nuanced details. That's why we have lawyers to sort things out when we finally get to the court proceedings. Your system would need to have a remarkable caste of lawyers to untangle it, especially resolving any inconsistencies which may arise.
However, it is not the lawyers that I want to focus on. You and I have an intuitive understanding of our particular legal system. We understand that if we do certain acts, that will be deemed "murder" and the justice system will be swift and servere. If we do other acts, they will be deemed "speeding," and the justice system is a bit more murky regarding that. There are plenty who will make informal arguments along the lines of "5mph over the limit isn't really speeding" or "I was just going with the flow of traffic." But in all cases, we develop an intuitive sense.
This intuitive sense is *essential* for making rapid decisions. The faster a situation changes, the more intuitive one needs to be. If I am an armed citizen of group X, and I have a law which says "I am allowed to shoot people who break the laws they abide by," and I see someone of group Y draw a weapon, I may have a split second to decide whether I should draw my own weapon, or if I need to back down because that particular action was *legal* by Y's rules.
The pressure to make these intuitive judgement calls will rapidly encourage the governments to generally unify the laws which may have effects on people making rapid decisions. Generally speaking, you'll find the rules for whether or not a person can have a firearm will become clearcut such that all citizens can intuitively respond to someone drawing a firearm in a legal and appropriate manner. It may be funny ("only people with red hats are allowed to have guns," and a strict ban on wearing red hats by anyone else), but the resulting agreed upon rules will be something that the members of all governments can intuitively understand and operate under.
This pattern will not necessarily happen for aspects of life which are slow enough to think through. In those cases, each government may indeed have their own laws. I came across a fascinating example recently on the Christianity Stack Exchange, where a [Catholic was asking whether his Buddhist fiance could be baptized while keeping her faith](https://christianity.stackexchange.com/questions/65780/can-a-non-catholic-receive-baptism-to-formally-marry-a-catholic-without-conve/65787). The answer was a resounding no, but further digging showed that the real issue was that he wanted the marriage to be valid in the eyes of his faith, so that he was not living in mortal sin his entire life.
To that new question, people were able to provide positive replies. The "lawyer" caste of the Catholics indeed had a process to permit a Catholic to marry out of their faith. They simply had to apply for a "dispensation for disparity of cult" from their Bishop. The Bishop could then choose to grant it, and generally speaking such dispensations are granted because it's an opportunity for the Catholic spouse to help their non-Catholic spouse choose to embrace Catholicism under their own freewill (rather than under the duress of "convert or we can't marry").
In the case of marriage, this is not a "spur of the moment" decision. Accordingly, specific nuanced laws like this dispensation for disparity of cult (that I had never heard of until I read the question) will probably survive in such a multi-government environment. Indeed, one could consider this specific case to be a practical real life example of such a multi-government system operating.
Sometimes this will affect the social dynamics. Consider a case with corporations. My employer has told me some particular piece of information is proprietary. You approach me, asking for it, saying "the laws of my employer permit me to know your employer's proprietary information." This can happen in real life situations. As such, it is now socially acceptable for me to slow this transaction down and get time to think. I'll say something along the lines of "Let's have your boss talk to my boss, and if our HR departments and general consuls agree that it is acceptable, I'll tell you that bit of information." Both of us work into our intuitive understanding of the system that it is acceptable to slow the process down to "thinking speed" and make sure we were legal. (And a great deal of the art of social engineering is how to prevent people from doing this)
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There will be problems, like your gun/monarchy example illustrated.
"keep the gun holstered" rule will not work - one figure out a way to fire a holstered gun, or just fire it and then run&hide, with the help of the same people who hired you to kill somebody in the first place. There could be a rule like "gun must be kept in a locked metal box", but it is still a hassle.
People will try avoid the hassle of different laws, by living & working & shopping in area governed by their law, or by converting to most convenient law). A republican shop surrounded by monarchist streets will have very little revenue business, and will close.
Over time, this "network effect" will split the city into districts, with most land and people within a district governed by the same law. If law is species-specific, districts make even more sense - each district is designed to accommodate size and climate preference of its species.
There will be "embassies" and "visitors", but they will be few, precisely b/c of the hassle that living under a different law implies.
You might have "second-class" citizens, like (legal) resident aliens in modern US, black americans before desegregation, black and native americans before 1861, serfs in Russia or medieval Europe, slaves in Rome, etc.
Also, a city will come to be dominated by a single law, if other people can easily move away (or be driven out or killed).
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Confused police, since they need to keep numerous different legal systems straight. Let's see, I'm a monarchist constable, wasn't there a law passed by the Republicans that applies to Republicans carrying that sort of gun? Last year or so? I'm a monarchist constable, and when I arrested that guy I read him the Bezos warning rather than the Miranda warning, because I have trouble remembering which warning the Fuzzoids use.
It's not like police are all that great at knowing the law nowadays. They have procedures that will keep them from committing illegal acts, knowledge of some laws, and leeway in making mistakes.
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A lot of worldbuilders that I know and have spoken too, insist that unbacked currencies and items with constantly changing values would be what the economy is based on. I, however, am skeptical of this.
Now, I am aware from reading lots of Atomic Rockets and my education, that in space pretty much any material resource isn't going to be terribly expensive. Gold could be made worthless, with the resources and technology one would use to get to Pluto in a few days.
I, however, own a few books about writing sci-fi and have books on history. I know that whoever controls the source of energy for each Era, stands to be the most powerful nation, empire, or faction in that Era. I know that pretty much every single nation values oil, and despite it going up and down in supply and price, there is always a huge demand for it. I know that oil companies do well on the Fortune 500 and Global 500.
Would it be feasible to back currency with energy, assuming I could hold all of the energy produced in a storage medium that didn't leak too fast?
Energy is used to get raw materials, energy makes them into finished goods, energy moves them from place to place, energy powers the tools to make buildings, it cools the houses, it warms the houses, it powers the lamps for the indoor farms, and it's used to make fertilizer for the outdoor farms.
If I can't back it with energy, can I back it with anything? Can currency be backed feasibly by people who travel from system to system in days or hours?
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Don't use *stored energy* to back your currency, use *energy production capacity* to back it.
Imagine there is a space colony somewhere on some forgotten planet. They have a problem: They don't have enough energy. So you as a friendly intergalactic entrepreneur settle down there and build a cold fusion power plant to cover their energy demand. But you are of course not doing this just because of the goodness of your hearth. In order to be allowed to use the energy your power plant generates, they need to provide you with the goods and services they produce.
You are now buying things for energy.
The amount of energy you let each colonist use will likely depend on how much goods and services they provide to you. One colonist might create those tasty green protein bars you like so much. You are willing to provide him with several GW of energy in exchange for a crate every month. But the guy who makes them doesn't actually need that much energy. However, there is also that guy who creates tools for all the colonists. In order to create tools, he needs to smelt metals, which is very energy-demanding. But you brought your own tools, and they work better than those made by tool-guy. There is nothing tool-guy could offer you for the right to use your power plant. But there is a solution: tool-guy provides his tools to protein-bar guy and in return protein-bar guy gives tool-guy some of the energy he bought from you with protein bars.
You just inadvertently turned energy into a currency.
Keeping track of all these deals among the colonists will become cumbersome to you. You want some easier way to keep track of who is entitled to how much power. So you create some kind of token which the colonists can trade among them and then give you in exchange for your energy.
You just created a currency backed by energy.
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The energy-backed currency in your world could be a form of rationing coupon for the use of energy.
The government recognized that the increasing energy demand around the world creates an unacceptable strain on the natural resources of the planet. The free market failed to regulate this problem. So they decided to ration the use of energy by distributing energy rationing coupons.
If you want to consume 1 kWh worth of electricity or burn some kind of fuel worth 1kWh for heating or propulsion, then you need to return a 1kWh energy coupon to the government. The government does of course realizes that some people need more energy than others. So the energy coupons are transferable. When a big industrial plant needs huge amounts of power, they need to acquire the necessary energy coupons from people who don't need all of theirs.
Regarding for what system the government used to determine who gets how many coupons: I could imagine lots of different distribution systems. Give them to natural people or to companies; equally to everyone, based on need or based on merit. Which method you choose could have severe socioeconomic consequences for your world. But the only thing which really matters about the distribution system when it comes to turning the coupons into a currency is that the government doesn't sell them for fiat money. If they do that, then their value would be coupled to that of the fiat currency.
Although they are called coupons, they might not actually exist as physical pieces of paper. They might just exist electronically in some government database or in a public blockchain.
When you have a good which is fungible, easy to transfer and needed by everyone, then it is ideal commodity currency material. After a few fiat money finance collapses, stock market crashes etc., these energy certificates might have proven to stay stable in value. So they might have become the de-facto currency at some point in history.
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Currently this is kinda already the case. The USD is backed by oil. If you have $100 (give or take) you can exchange it for a barrel of oil, and vice versa. Now the USD is only loosely pegged to the price of oil, (The price is adjusted by things like: sell military equipment cheap for a few favours on production output, release some reserves when prices get a bit high, go to war with any smaller countries that try sell oil in euros, that kind of thing)
A good currency needs to be:
1. Divisible (so you can get change)
2. Transferable
3. Have some sort of backing
4. Is reasonably stable price
*As a side note Bitcoin does really well at 1&2, but poorly on 3 (a combo of it's utility of 1&2 + the size of the Bitcoin economy (the amount transferred daily which currently is much smaller than the whole pool of coins)) And point 4, Bitcoin is currently too volatile to be a useful currency*
The USD used to have gold as a backing. But because of the French gaming the system President Nixon changed it to be backed by the US Government, or effectively the US economy. Which for reasons also includes almost all of the International oil trade.
So for your world building, raw material commodity prices fluxuate wildly; as astroids get brought into the Luna dockyards, some worth dozens of credits, others just piles of useless gold and gravel. However the lowest common denominator is always energy, antimatter to be precise.
Antimatter is *divisible* (you wouldn't want to fuel up a ship with more than 100 milli (grams) now would you.
Antimatter is *Transferable*. One gram (one credit worth) is easy enough to move from (person) A to B; even in it's containment vessel. FWIW one gram is enough energy to be equlivent to that released on Hiroshima and Nagasaki by the US in WWII
It is backed by it's own value and utility.
Any ship larger than a fusion powered rock-hopper is going to need antimatter. In the same way virtually all of present day's transportation (air, train, plane, automobile, truck) uses oil.
Creating antimatter requires a **Huge** investment in cyclotron infrastructure. The "Corporation" was the first and only entity to build a luna antimatter factory and basically captured and controls the market.
After some big price fluxuations in gold, titanium, water etc., as the first antimatter delivered astroids started coming in, a lot of mining outfits started going bust because they could not afford to refuel their ships. The "Corporation" started issusing "Antimatter Credit **[future's](https://www.investopedia.com/terms/f/futures.asp)** ", which can be exchanged for antimatter, on delivery of an astroid; irrespective of the current commodity spot price. Before long Credits became the defacto currenency of the off world economy.
Because Credits can be exchanged for something of fixed value (1g of antimatter), which has great utility, and the whole space economy runs on it; its value is very stable. Plus the future's contracts, helped even out the price fluxuations of astroid derived commodities.
One Credit is worth a fortune so when someone refers to a credit ( credit with lower case c or ¢) what they really mean is a micro credit, one millionth of a credit. Change is given in mil or milli, one 1000th of a small ¢redit. For perspective 2 mil will buy a can of cola.
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I am afraid that using only energy is not enough. Take a simple system: a brick hung 10 meters above the surface of a pool. We can say it has a certain amount of energy, in form of gravitational potential energy.
If we now cut the rope and let the brick fall in the pool, we will have at the end the same amount of energy, dispersed into heat.
Is the content of energy the same? YES
Is the value of energy the same? NO
If my whole universe was the system above, I would value 10 credits of potential energy way more than the same 10 credits in thermal energy.
Lesson is: take into account the entropy.
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Storing large amounts of energy is hard. Batteries don't hold very much. So where are you getting energy from?
Nuclear, rare isotopes. Eg U235. The nuclear fuel is hard to extract and is a great source of energy, hence valuable.
Nuclear, common isotope eg H1. The limit on producing energy is reactor time, not raw materials. A gigawatt (Big power plant) fusion reactor needs the hydrogen from a tap that drips once every 2 minutes. Reactors could still be valuable, raw materials aren't. Storing energy in batteries is stupid unless batteries are cheap and reactors expensive and demand spikes a lot.
Solar, Panels may be valuable, as might be a promise of energy at some future time.
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Say a computer running an AI exists on a planet with no biological life. Say it has access to a rather extensive preexisting manufacturing plant and can control a fleet of machines capable of performing the whole process of mining and transporting raw material to build and assemble more machines, fabricate replacement parts, or build new things of its own design. Can it maintain itself for a long period of time?
What possible challenges and dangers would it need to overcome, and how might it do so?
What natural resources must be available for it to build space traveling vehicles, capable of gathering further resources? Would this even be a feasible course of action for it?
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Updates for greater specificity:
Assume its hardware and construction is similar to a present-day earthly supercomputer (just bigger and hand-wavily enough faster to run the AI in real time). For fun, geological stability, and difficulty in resource extraction, lets say it starts out on (or in) a largish asteroid (rather, a smallish moon) in orbit around a the previously mentioned lifeless planet. Lets say the planet is rocky and rich in similar elements as earth. Say this planet had some plant life at one point, so there is carbon and oil which can be extracted for plastics (at least for a little while).
It has access to a nuclear power source, so it isn't necessarily dependent on getting energy from the system's star, but that's an option too.
The AI's goal is to learn as much as it can, so it may have an interest in sending probes to other systems. Or going there itself, if it can fit itself out with ion drives and carry enough $\Delta v$ to escape one system and arrange to be captured by another.
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A Similar Concept has been explored by scientists already, they are called Von Neumann Probes, basically their programming is to travel to a star system, map the system, mine any asteroids to self replicate, and then send onto another system. this in theory could leave a satelitte in every system in the galaxy if left long enough, the issues come down to avoiding any debris sitting between star systems. however we already have the technology availble to us to send one of these probes, however the "self Replicating part is not 100% perfect, and more importantly it would take so long that by the time the first probe reached our closest star, Alpha Centauri everyone that remembered the launch would be long dead. yes our childrens children would be able to see the results after it took a few years for the signal to return to earth.
The reason they haven't tried making one yet is that a lot of scientists belive it is better to wait until we have engines capable of reach another system in say 50 years, then to send it.
I appreciate that this isn't a single large AI, but a small one copied billions of times. but if this were a single large AI controlling many machines, then it would need to do the same sort of job just exponentially bigger
**Resources**
These are basically everything AlexP mentioned plus a few more
The main ones would be Gold, Silicon, Copper, Palladium and Aluminium, these would be for microchips circuitry, capacitors and wiring,
Then of course, Iron, Carbon, Zinc, Vanadium, Tin for the body of the probes. many of these elements already mentioned also make up photo-voltaic cells (solar Panels) as well as lithium for making the lithium compounds to use in making the batteries.
Then just mine ice for hydrogen and oxygen to use as fuel,
there are a lot more then this but rather than listing them all or simply adding a link to the periodic table, these are the most important that i can think of.
[Answer]
**Programming the AI is a challenge**
Having dabbled in programming - the big problem with AI is not going neurotic.
You can programme an AI to deal with as many known issues that can be foreseen - but millions of years is a long time. Imagine on this planet backwards several million years. We had:
* continents changing
* several ice ages
* complete animal life change
* atmospheric changes
* geological changes
* probably innumerable solar flares
* all sorts of things.
Not only are the conditions changing, but AI itself depends on self improvement and learning algorithms - I cannot foresee an AI self-learning and programming to last millions of years before going belly up eventually, especially if made from scratch.
Unless - the AI is actually at the tail end of a billion year process of programming it - in other words it survived where other AI had not.
The resource stuff I would imagine is easy, unless it's in a hard-to-get-to spot where the AI won't destroy itself trying to get at it...
[Answer]
## The AI survives so long by becoming Alive then Dying
The only systems that we have seen that can survive for millions or tens of millions of years is life itself in the form of ecosystems. No individual life form lasts very long but the system itself survives the required millions of years.
In contrast, we see that centrally designed and implemented systems by humans (and only by humans since nature only does distributed design) fail regularly and spectacularly. Even very resilient human systems may survive for a long time but inevitably, something will change and the system crashes.
A big, central AI is a single, exceptionally expensive bet that *will* fail and likely soon. Designing and programming this system to survive a million years is a fool's errand.
This AI will have to deal with failing hardware, failing network connectivity to other compute nodes, death of the factories, break down of the mining facilities, exhaustion of local minerals, environmental changes that can't be anticipated in advance, failure to maintain normal operating parameters in the datacenter where the AI lives. Basically, every struggle that life now solves, this AI is going to have to replicate with machines and it's own programming.
It will also have to deal with the failure of the AI itself. The AI will evolve over time and develop cruft. This may be in the form of suboptimal action potentials that can't be changed without starting over. Maybe there's random corruption in a single bit in the exact wrong place. Life solves this by having everything die. Birth gives fresh starts and new chances to experiment with things. It will need smaller, more agile AI/robots to survive the lean times/extinctions when it's just too expensive to be a big AI/robot.
If this AI is going to survive, it *must* build an ecosystem to support itself. It must have children and it must adapt to meet the local circumstances. Failure to do so means failure to survive for the required timeframe.
[Answer]
Self repair and software redundancy. The machine would need to be able to repair itself and also have multiple backups for every process. Something like 5 layers of redundancy should work, basically any time it does anything it compares the action to 5 templates to see if its the same. If one of the templates is different than the others it re-references the other 4 then makes the damaged 5th one the same as them. This applies to every single action the AI takes, which means in essence you actually have 5 AIs running 5 identical sections of the ship constantly checking eachother for uniformity and operating as a consensus.
A note on AI, the idea of one rebelling is kind of silly, since that is confusing artificial intelligence with artificial conscioussness. The AI does not need to actually be self aware to do this job. As a matter of fact, no AI really needs to be self aware to do its job. Im imagining a ship that is 5 cylenders in a hexagonal bundle with 5 engines and 5 sensor suites and 5 reactors and 5 repair bays etc etc. Each AI runs one section which is itself fully capable of travel, resource extraction and refueling, repair, etc etc. Whenever any action is taken all 5 cross reference the decision with eachothers databases. In the event of an extreme emergency or failure the 4 AI will destroy the faulty 5th and even be capable of completeley rebuilding the destroyed section and replacing the now gone AI with a new copy of themselves.
[Answer]
Your second question has been well addressed, so I’ll focus on the first instead.
The greatest dangers would be corruption in replication (digital cancer), fluke disasters, and data storage.
The issue of corruption has been elaborated on already with the idea of the five systems template, so I won’t add anything to this point.
Fluke - or extremely rare - disasters would be a significant danger in the sense that the longer the AI exists the more likely it is to encounter them. To survive for millions of years the AI would need to distribute itself in a variety of ways, being more like a hive network than a single entity. The machine parts need to be designed and distributed diversely to ensure continuity throughout a range of catastrophic events - asteroid impact, solar flare, super volcanoes, etc. it would also need to develop tools to protect itself proactively.
Finally, you state that it’s purpose is to collect data. Collecting and storing raw data about everything in the universe would require ridiculous volumes of energy and raw materials for storage. Without any kind of data refinement you’re going to very quickly need to acquire resources and energy at exponential leaps.
This will probably be the biggest constraint on the AI.
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[
Tree growth rings are created because the time of day with sunlight differs throughout the year. How would the inside of a tree look, if it were to grow up on a planet without seasons, where day and night are always 1:1? I tried to look for studies on growing trees under artificial light, but couldn't find any.
[Answer]
While it is true that tree growth rings are mainly due to seasonal differences in sun exposure they can also be caused by changes in humidity, temperature and rainfall patterns amongst other things.
Indeed in the tropics there are only tiny shifts in light levels year round and because of this many trees there tend not to have any visible growth rings at all. Yet because of the seasonal shifts that do in fact occur (namely changes in the rate of precipitation, a.k.a. wet season vs. dry season), some species of trees have subtle growth rings that reflect this. [Teak in particular is one tropical species that usually has very apparent rings.](http://www.tandfonline.com/doi/full/10.1080/21580103.2013.834275?utm_source=TrendMD&utm_medium=cpc&utm_campaign=Forest_Science_and_Technology_TrendMD_1&)
So essentially, if there are *absolutely no* seasonal changes to the environment of a tree, there won't be any growth rings. The cross section won't be completely homogenous however, they'll still be features such as the dead heartwood at the center of the log and the living sapwood which is typically lighter in color. On the other hand, if you do indeed have seasonal changes apart from illumination, then your tree may still have growth rings (though they'll tend to be less pronounced).
[Answer]
**Tropical trees have rings.**
<https://www.researchgate.net/publication/269621255_No_growth_stimulation_of_tropical_trees_by_150_years_of_CO2_fertilization_but_water-use_efficiency_increased>
These researchers used the growth rings of tropical trees to study the possibility of growth stimulation by increasing CO2.
>
> The biomass of undisturbed tropical forests has likely increased in
> the past few decades, probably as a result of accelerated tree
> growth... However, there is no evidence that these physiological
> responses do indeed stimulate tree growth in tropical forests. Here we
> present measurements of stable carbon isotopes and growth rings in the
> wood of 1,100 trees from Bolivia, Cameroon and Thailand.
>
>
>
[](https://i.stack.imgur.com/oCPEK.jpg)
It is not stated why exactly they chose tropical trees - maybe because all other factors are more constant, or they could find really old trees more easily? The image of tree rings is not the end-on sort of view I am used to but there they are. There must be some cyclical change. This might be intrinsic to the tree, not the environment - for example a tree might shift its resources to making seeds and fruit instead of wood at certain times of year.
---
If you want your alien tropical trees to have rings, have them cycle in some way as noted and that can do it. Or have them be trees without rings - palm trees do not have rings. Bamboo is a grass with tree ambitions and it does not have rings.
[Answer]
>
> How would the inside of a tree look?
>
>
>
On Earth we have an example of a tree with no growth rings, even though it is not caused by seasonal changes.
The [palm tree](https://en.wikipedia.org/wiki/Arecaceae) is such an example
[](https://i.stack.imgur.com/SlTTX.jpg)
As you can see from the picture above, there are no visible growth rings, so I guess it would look something like this.
[Answer]
If your planet has a moon, rings could be related to lunar cycles, or to tides.
If you want a longer cycle to affect your trees... The trees might have some biological trigger on them so that they only develop a ring if they get a short period of darkness between two long periods of light - that is, a solar eclipse.
On Earth those happen multiple times a year, but every time they happen on a different place. Once an eclipse happens over an area, it usually takes years for that to happen again. [A completely similar eclipse over a single area usually happens every 18 years](https://www.timeanddate.com/eclipse/how-often-solar-eclipse.html).
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My magic system involves all organisms producing a sort of energy field that acts as their immune system. If someone casts "too big" a spell - draining too much of their energy and compromising their immunity - they obviously are vulnerable to all kinds of illness and disease.
My question is: what are some of the most common types of illness these unfortunate souls might have to deal with? I'm looking to identify a few different diseases (or at least sets of symptoms) that people might specifically associate with magic users bc of this effect.
[Answer]
This answer is based on the [Wikipedia page](https://en.wikipedia.org/wiki/Signs_and_symptoms_of_HIV%2FAIDS) for symptoms of HIV/AIDS. Hat-tip to [@pojo-guy](https://worldbuilding.stackexchange.com/users/19171/pojo-guy) for the idea.
>
> Look at the illnesses that HIV victims get. - [pojo-guy](https://worldbuilding.stackexchange.com/users/19171/pojo-guy) `2018-01-07 04:05:41Z`
>
>
>
The page *seems* to be well-referenced, but as I’m not a virologist, I’ll leave this information for you to look at, and for someone with more expertise in the field to determine its accuracy. From the very few (read: one) discussion I’ve had with virologists on HIV, this all seems to check out.
The idea behind this answer is pretty straightforward: if you’re asking what will happen to a fictional compromised immune system, well, let’s see what happens to a real compromised immune system.
---
According to the article, in the early stages of AIDS, an HIV victim may have:
* Fever
* Malaise
* Muscle pain (Myalgia)
* Rash
* Headache
* Night sweats
* Sore throat (Pharyngitis)
* Lymphadenopathy
* Joint pain
* Nasal congestion
* Mouth/Esophageal sores
* Nausea/vomiting
* Fatigue
* Mouth ulcers
* Genital ulcers
* Enlarged liver/spleen
* Weight loss
* Thrush
* Diarrhea
* Neurological issues
While these are all symptoms caused by very common bugs, things are much worse for people in the much later stages of AIDS. Ultimately it comes down to what viruses, bacteria, fungi, and parasites are active in the region, but ultimately literally anything can infect a person whose immune system can’t stop it, leading to victims of HIV suffering from anything from GI disorders to pulmonary disorders to neurological disorders to cancers to mushrooms growing on their faces.
So, in short, literally, any disease can attack your mages. It just depends on what’s common in the region and how compromised their immune system is. I would work on developing a spell that boosts their immune system.
---
As an aside, the immune system works by detecting foreign substances and killing them off. This includes cancers. In all likelihood, everyone reading this post has had cancer before; the immune system just usually deals with it. The deadly cancers are the ones that can disguise themselves well enough to hide from the immune system.
Why do I bring this up? Well, if your mages’ immune system is a ball of energy acting as a shield from the *outside*, what happens when the mages’ own cells begin attacking them, from the *inside*?
[Answer]
A problem, from a story-telling aspect, is that a lot of opportunistic infections (those that prey especially on the immunosuppressed) seem pretty similar from the outside: fever, cough, feeling bad, maybe acting weird, maybe losing weight. Not that great for a story.
There is, however, a problem for the chronically immunosuppressed that would lend itself well to a story.
**Skin cancer.**
[](https://i.stack.imgur.com/J0yK3.jpg)
Depicted: multiple horny cancers on the arms of a chronically immunosuppressed woman.
[Cutaneous Squamous Cell Carcinomas in Organ Transplant Recipients.](https://www.ncbi.nlm.nih.gov/pubmed/26239556)
>
> Non-melanoma skin cancers represent a major cause of morbidity after
> organ transplantation. Squamous cell carcinomas (SCC) are the most
> common cutaneous malignancies seen in this population, with a 65-100
> fold greater incidence in organ transplant recipients compared to the
> general population
>
>
>
The immune system is important for holding back squamous carcinomas of the skin. When the immune system wanes, either with age or because of disease or medicine, people develop more skin cancers - sometimes hundreds of skin cancers. Some of these can be deadly but most are just disfiguring - scaly, bleeding lumps and crusts. Skin cancers can sometimes produce fingernail-like horns also; one can be seen in the image above and a google image will find more. Growing bleeding, scaly horns out of random places in the body seems like a good problem for an overextended magic user to have.
Besides skin cancers, people with this immunsuppression skin issue also develop many warts, which are cotravelers with the cancers and are also disfiguring. Warts and witches are like peanut butter and jelly. Maybe not exactly like that but you get the idea.
Both of these issues leave the afflicted person functional and sane which is good from a storytelling perspective. I like the idea of the afflicted wizard using magic to get rid of particularly troublesome spots - which of course makes the underlying problem even worse.
[Answer]
A few illnesses automatically spring to mind.
First up, the common cold. Yeah I know it seems obvious but it is nearly omnipresent and one of the most infectious diseases on the planet. Anytime someone's immune system gets too low you will get a cold at least.
Second, strep throat. This bacteria is part of the natural bacteria that is present on the skin. Once again, if your immune system gets too low, you will get infected with strep throat.
Third is pneumonia. This kills lots of people a year, and its primary target are people with weak immune systems. The old, the sick, and the very young are all susceptible because they lack the strength to defend against it.
These three are just the first ones that pop into my head, and anytime that you are messing with a person's immune system you can have allergic responses and even sunburn-like symptoms. Past that you can get into auto-immune disorders, and if the immune system breaks down or shuts down, any infection will quickly become serious if not lethal.
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Don't forget that aside from the diseases that have been already listed, you could also make old, since long disappeared diseases make a comeback due to a widespread weakening in people's immune system, much like how the fact that people refuse vaccines nowadays causes the resurgence of old diseases. Some that come in mind are various strains of the pest, spanish flu, cholera, etc.
[Answer]
If the magic system involves all organisms producing a sort of energy field, and this energy field itself is the source of magic (this is strongly implied but not explicitly stated) dividing its influence between projected magical effects and immunological effects (implicitly magical), then logically those magical immunological effects could be expected to be weaker against pathogenic organisms who, implicitly, also have their own magical immunological fields protecting them and therefore increasing their ability to cause illness.
The question then would be which of those pathological organisms would be strongest in terms of magical immunology, because they would be the ones to benefit greatest from the weakening of the magic users energy field and, therefore, most likely to triumph.
Excluding prions, which would not normally be considered as organisms, our [pathogenic organisms](https://en.wikipedia.org/wiki/Pathogen) are:
viruses,
bacteria,
fungi,
protozoa,
[worms and other large parasites](https://en.wikipedia.org/wiki/List_of_parasites_of_humans)
Individually, those with the greatest magical immunology would be expected to be most effective in causing disease, although it is unclear whether weight of numbers might be a factor, it depends how scalable magical immunology might be. It also depends upon likelihood of initial infection - it may be easier to catch a virus than a tapeworm or flea in clean environments.
If we just consider size as being the critical factor in magical immunological defence, then large parasites and the diseases they introduce obviously have the advantage. All being equal in terms of likelihood of the pathogen being encountered, [these diseases](https://en.wikipedia.org/wiki/Parasitic_disease) will predominate.
Diseases not caused by organisms will not benefit in quite the same way that pathogenic organisms will from a weakening of magical immunology (pathogenic benefit twice: once from general weakening of the immune system; secondly from enhanced magical immunological protection). These include [Prion diseases](https://en.wikipedia.org/wiki/Transmissible_spongiform_encephalopathy), cancer and other non-pathogenic diseases.
I've made quite a few assumptions here, but I've tried to develop some kind of rationale for how the magic immunity will work.
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For one of my fantasy humanoid races, I am conflicted on whether to make them digitigrade or not. A big question that comes to mind for this, is how shoes might work for a people with feet similar to say, a wolf or lion (no, these guys do not have hooves).
Perhaps something like a roman sandal might work?
[Answer]
A quick search gives you some hint on how a shoe for a dog can look like (in this case a snow shoe)
[](https://i.stack.imgur.com/0zGhI.jpg)
I think that's a starting point for your design: fasten it around the ankle, seconding the natural movements of the joint.
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In my world there are humans who have undergone a mutation from being exposed to a certain kind of magic. They have not realized they have been mutated until they start noticing that they have the ability to see well in the dark (low light, not total darkness). Outwardly, they look the same as they did before the mutation, which is why no one noticed they had been mutated. They can also see just fine in the daylight as before.
I'd like to avoid a 'they can see in the dark because magic!' situation, and put more focus on the effects of mutation and how their eyes have changed biologically.
So, biologically speaking, how would the human eye need to change in order to see in near darkness without any major changes to physical appearance (like larger than normal pupil dilation)? Also, could this happen without jeopardizing the ability to see in daylight?
[Answer]
# The retina is finally turned the right way around
If ever you have poked around in the [Evolution vs Intelligent Design](https://en.wikipedia.org/wiki/Intelligent_design_and_science) debate, you will have noticed the [irreducible complexity](https://en.wikipedia.org/wiki/Irreducible_complexity) argument that says that the **eye** is much too complex to have evolved, so it much have been designed by some intelligent being.
Well that supposedly "intelligent" being then did something really stupid:
**They mounted the [human retina](https://en.wikipedia.org/wiki/Retina) *backwards***
[](https://i.stack.imgur.com/ghXKf.jpg)
*The light sensitive parts of the retina are to the far right. Lots of junk that light has to pass through before getting there. ([Image source](http://www.microfinancemonitor.com/is-human-retina-built-backwards-yes-confirm-scientists/29133))*
In an evolutionary mishap, the human retina became such that the light sensitive parts of it is pressed up against the wall of the eye, while the nerves come out inside the body of the eye. This is inconvenient for several reasons, including getting a blind spot in the eye, and having much less light sensitivity than we could have had.
So the easiest way your magic mutation can give us **much** better vision than before is:
* Flip the retina the right way around, placing the light receivers facing the light instead of the back of the eye, and no nerves in the way.
## Bonus changes...
* Do like on cats and dogs, and add a [tapetum lucidum](https://en.wikipedia.org/wiki/Tapetum_lucidum), that is to say a reflective layer right behind the light receptors. This makes more light available to the receptors.
Also we have another really silly peculiarity. In low-light conditions, our most light-sensitive cells are not in the center of our field of vision but on the edge. This means that we can see things "out of the corner of our eye", but as soon as we turn to look at them, they go away.
* Make the most light sensitive cells be gathered in the center of our field of vision, not on the outside of it.
And in order to protect the eye and make it less painful to experience this brighter light, especially in sunlight...
* Make the cornea and the lens of the eye be a filter for ultraviolet radiation.
This is because it is mostly UV that hurts the eye in strong light conditions, not visible light, or at least not quite as much.
All of these things can happen without any visible change to the human appearance...
**...except that instead of getting red pupils in a photograph, they will get green dittos.**
[](https://i.stack.imgur.com/r18fd.jpg)
*Dogs, cats and more get green eyes when photographed thanks to the **tapetum lucidum**.*
*([Image source](https://en.wikipedia.org/wiki/Tapetum_lucidum#/media/File:Black-Lab-3-months-old-puppy.jpg), License CC BY-SA 3.0)*
[Answer]
Real life adaptations to increased night vision include increasing the density of rod cells in the eye and dilation of the pupil. With normal human eyes, you adjust to the dark in about 5-10 minutes. Nocturnal animals have adaptations like specialized rod cells or a tapetum Lucindum that maximize the low light levels at night.
The problem with biological adaptations seen in nocturnal animals is that it may make it harder for your humans to see different colors and focus on things in bright light. With magic you could have them adjust quicker to darkness and dilate their pupils at will, but I don't know how to trade off the downsides.
[Answer]
I'm not sure if this fits your definition of "They can see in the dark because magic", but allow me to provide a shift in focus:
Their eyes are noticeably mutated and do change in appearance in darkness. However, they are magically *concealed*. Instead of trying to come up with a -probably inaccurate to some extent- semi-scientific eye model that is largely superior to the human eye without being aesthetically different, isn't it easier to actually let their eyes be different, but people just don't notice it? Of course, if there's magic in your setting, there are ways to suspend this illusion, and a powerful enough mage/sorcerer/wizard etc would potentially be able to see through that kind of thing, but if they're in your average village or city, there's most likely not going to be one of those powerful people around.
That being said, here's an alternative answer that actually(maybe) responds to your question:
Probably not. Either they would have the thing that cats and dogs do(Which would make their eyes reflect light as if they were a mirror depending on the angle)
or they would have a lot more of rod cells(which would either affect their ability to see in daylight, as if they had photophobia, or cause their pupils to contract absurdly when exposed to "normal" lighting conditions). I can't really think of other ways to *see* in dark ambients that are natural, but perhaps if they could *perceive* that ambient without relying solely on vision(Something sonar-like) it could be done and they wouldn't necessarily have an all-enhanced hearing, you could get away with them being able to hear what a normal human does *and* the frequency of the sonar without hearing the frequencies between them.
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Similar to other suggested dynamic structures using kinetic energy to provide structural support, I am considering options for resisting external pressure in a vessel (e.g. a diving bell) by incorporating magnetically supported rotating hoops into the hull. The principle would be similar to an [orbital ring](https://en.wikipedia.org/wiki/Orbital_ring) but at a much smaller scale, with the force resisting external pressure rather than gravity.
[](https://i.stack.imgur.com/EBq4j.jpg)
I am pondering Options for the circulating mass with angular momentum which will generate the centrifugal pseudo force:
1. Hoops of copper
2. Hot Plasma
3. Cold superfluid
4. Bose Einstein Condensate.
Question 1: do you see any fundamental - show stopper - reasons this idea could not work (in a Hard SciFi context respecting the laws of physics)?
Question 2: which if any of the materials are suitable? (My preference for narrative reasons would be 4. then 3. then 2.).
[Answer]
**Is there any fundamental--show stopper--reasons this idea could not work (in a Hard SciFi context respecting the laws of physics)?**
No. It's a perfectly fine idea.
**Which materials are suitable?**
If you can use a superfluid, then a lot of engineering problems get a lot easier. The whole point of superfluids is that they flow with zero viscosity, so once you get it rotating in the pipes, it'll just keep going, with no need for magnetic confinement or replacement of frictional losses. On the other hand, you now need a really good refrigeration system, and there is the question of how you get it started moving in the first place. There are certainly ways to do it; it's just not obvious what the most practical engineering solution would be.
In an SF context, you could always make up some new exotic superfluid material to use for this purpose. If we're sticking with known, real materials, however, the superfluid option is going to require helium (probably helium 4, since it's much more common and transitions to the superfluid state at a higher temperature than He3). Superfluid helium *is also* a Bose-Einstein Condensate, so there's you top-two choices already taken care of. The fact that it is a BEC is, however, not really relevant; yes, its BEC nature is part of the explanation for *why* it becomes superfluid, but your engineers won't need to care about that. All that matters to them is that it is, in fact, superfluid. Bose-Einstein Condensates do not generically lend themselves to this application.
Using hot plasma is a *bad* idea. It's incredibly difficult to control, and you'll want something with a relatively high density to provide the maximum counter-force.
Copper would work, making use of its diamagnetic properties to "levitate", pushing against permanent-magnetic bearings in the outer wall. It's far from the best solid material you could use for this purpose, however. You wouldn't want to use just a continuous band of copper; it would need to be broken up to minimize induction of eddy currents, which will sap energy and momentum from the system. Rings of bismuth and/or pyrolytic carbon would be much more effective, as they are much stronger diamagnets. Unlike the superfluid option, which can just use regular ol' static pipes to circulate the fluid in, using solid rings like this would require some kind of active support; the main load-bearing elements could be simple permanent magnets, but you'll also need an electromagnet, or air cushion bearings, or some other control system with *extremely* fast response times to make sure they remain in their tracks. If that fails, your pressure vessel gets rather violently torn apart.
The upside of this sort of system is that, while there are some significant system control issues to solve, the basics of how to build and supply power to the system, and rev it up and down, are much more straightforward, and the materials are cheap.
[Answer]
Ah yes! This brings back memories. It's our old friend the centrifugal submarine. Originally discovered while digging back through very early issues of *New Scientist*, probably first published in 1964 or 1965, and appeared in the magazine's humorous science column. Each week *New Scientist* published fabulous invention after fabulous invention devised by a wonderfully creative scientist under the pseudonym of [Daedalus](https://en.wikipedia.org/wiki/David_E._H._Jones). Daedalus was named after the Daedalus of ancient Greek myth and legend, who was a epitome of the creative inventor-scientist. Despite minor setbacks like wings used by Icarus to fly. OK so wax melts, but that's only due to the lack of suitable fabrication materials.
The man behind the Daedalus pseudonym was David EH Jones, a chemist, who consistently devised wacky contraption after wacky contraption for weekly publication. The contraptions were usually based on a seemingly plausible application of a physical, mechanical or chemical principle. Jones conceded there was often a [flaw in the reasoning](https://www.theguardian.com/science/2017/aug/18/david-jones-obituary) that made his contraptions impossible, impracticable or dangerous to use.
>
> Daedalus and his fictional company, Dreadco (Daedalus Research
> Evaluation and Development Corp), set out, like many scientists, to
> trace the consequences of a “what if” idea. The difference for
> Daedalus was that he built in an intentional flaw. While professional
> scientists find all too often that their ideas fail, Daedalus
> anticipated failure but instead sometimes found that his ideas
> succeeded. In 1966, he proposed to make hollow molecular balls by
> persuading sheets of graphite to close up (graphite is composed of
> sheets of carbon atoms arranged like chicken wire). In 1985, Harry
> Kroto, Robert Curl and Rick Smalley described just such a molecule,
> carbon-60 (now known as a buckminsterfullerene), for which they
> received the Nobel prize in 1996. A mutual friend pointed out the
> Daedalus column to Kroto, who acknowledged it in his Nobel lecture.
>
>
>
After a long run of publishing in *New Scientist* for 24 years Daedalus (Jones) was poached by *Nature* and *The Guardian* where he continued until 2000 when he retired Daedalus due to a stroke.
Daedalus proposed that a submersible vessel instead of relying upon a heavy and sturdy hull to protect itself from the external pressures of the deeps could make use of centrifugal force to supply the dynamic counter-pressure. This proposal suggested that the liquid metal mercury would be the suitable circulatory mass to apply the centrifugal force necessary to support the hull of the submersible. Mercury would be a better choice than the suggested (a) Hoops of copper, (b) Hot Plasma, (c) Cold superfluid, or (d) Bose Einstein Condensate. It is readily available material and at a reasonable cost. Also, it wouldn't present insuperable problems managing it. Hot plasma or superfluids, oh no! Too many problems dealing with them under normal temperatures and pressures even in a diving bell at great depth.
The proposed rotating mechanism for dynamic structural diving bell sensibly keeps the cabinet where the crew and personnel would be located separate from the external spinning structure. Its main disadvantage would be the need for continuous power to maintain the centrifugal mechanism. The slightest power or engine failure could lead to rapid catastrophic failure. Something best avoided.
Toby Weston, sir, it is my sad duty to report that Daedalus (David EH Jones) published first and any patent disputes will need to be resolved in court. This would not the first time one of Daedalus' contrivances turned out to a workable invention nor will be the last.
In summary, it is recommended you consider the suitability of the mercury-filled centrifugal submersible as devised by Daedalus in the 1960s, only now is science and technology catching up with his genius, as the template for your dynamic structural diving bell.
IN MEMORIAM: David Edward Hugh Jones, scientist and writer, born 20 April 1938; died 19 July 2017. A creative mind who will be sorely missed by all those who love exploring the consequences of "what if" ideas.
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[Question]
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Imagine a desertic planet, large dune seas and barren rocky wastes ... Mountains and the like suggesting a past geological activity and even water once exhisted on the surface.
Now though the planet is fully desertic, it has a human breatheable or partially breatheable atmosphere (for brief periods before having to rely on the use of masks breathers).
My question is the following: how could such a planet justify the atmosphere?
My idea was for example large underground water caves, may be some sort of fungi ? Lichen or else producing a sort of reaction to make it breatheable?
Volcanism and thermal activity could be acceptable eventually.
The planet possibly should also have a warm or hotter climate at least on the central bands.
Thanks for any answer :).
[Answer]
There's two ways to do this. First is to explain why the desert planet has a stable atmosphere suitable for humans. Second is to simply say humans happened to show up at a time in the planet's history when it happens to have an atmosphere stable for humans. Depends on what kind of story you're writing.
# If It Didn't, There Would Be No Story
If this is a planet that humans chose to colonize, then it wasn't chosen by chance. It was chosen *because* it happens to have the right circumstances right now to be suitable for human life. And [there's enough planets out there](https://en.wikipedia.org/wiki/Exoplanet) that you're going to find at least one of even unlikely configurations.
The atmosphere doesn't have to be stable. While over [geological time](https://en.wikipedia.org/wiki/Geological_time) it might become unsuitable for humans, that's still time for thousands of years of civilization. And humans have [proven very good at altering their atmosphere even accidentally](https://en.wikipedia.org/wiki/Climate_change).
So, for the purposes of your story, you can lean on the [weak anthropic principle](https://en.wikipedia.org/wiki/Anthropic_principle#Variants) which basically says if the environment were not suitable for human life, we wouldn't be there to complain about it. You don't have to explain why it has a suitable atmosphere, the colonists might not even know, it just does. If it didn't, then they would have chosen some other planet with a suitable atmosphere. Even if they didn't choose the planet, even if they crash landed, if it didn't have a suitable atmosphere there would be no story.
With that bit of hand-waving out of the way, let's go into the issues with keeping an atmosphere suitable for humans.
# Atmospheric Oxygen Likes To Party
Contrary to the sci-fi trope, you're more likely to find abundant water than you are to find abundant oxygen. Water is a byproduct of many, many [exothermic reactions](https://en.wikipedia.org/wiki/Exothermic_reaction) and relatively stable. If you oxidize (ie. burn) many things, you get water and lose O2.
The problem with a nitrogen-oxygen atmosphere is oxygen likes to react with *everything*; that's why we call it ["oxidizing"](https://en.wikipedia.org/wiki/Oxidizing_agent). If your planet, for whatever reason, developed a nitrogen-oxygen atmosphere suitable for humans it would be difficult to maintain it. Over geological time the oxygen would react with any number of things to produce other substances (such as water) and the atmosphere would become unbreathable.
In order to maintain a level of oxygen comfortable to humans, you need some mechanism that continuously replenishes atmospheric oxygen. Or you need humans to show up at just the right geological time, another application of the weak anthropic principle.
On Earth the mechanism for sustaining the atmospheric mix is life. Life is continuously maintaining the atmosphere's careful balance to sustain itself, while also evolving to match long term changes in the atmosphere. Photosynthetic organisms add oxygen, [aerobic life](https://en.wikipedia.org/wiki/Aerobic_organism) removes it. IF you decide your desert planet has life, it would also have to need a nitrogen-oxygen atmosphere.
Making atmospheric oxygen by geological means is a problem. Because it is SO reactive it requires complex chemistry and energy to make it. This is why, for example, it's a by-product of photosynthesis. Plants get free energy from the Sun, use it to get the carbon they need from CO2, and O2 is the byproduct.
# Toxins
Humans can withstand large variations in the [partial pressure](https://en.wikipedia.org/wiki/Partial_pressure) of oxygen, but not of other trace gases. [Carbon dioxide, for example](https://en.wikipedia.org/wiki/Carbon_dioxide#Toxicity). At 0.5% it will cause headaches and fatigue. At 1% you get drowsy. At 7% you die. Since carbon dioxide is a byproduct of many chemical processes, you need something removing it from the atmosphere.
On Earth, this is plant life and other photosynthetic organisms. Photosynthetic organisms remove CO2 (they need the carbon), aerobic organisms add it.
There are [non-biological ways to remove CO2](https://en.wikipedia.org/wiki/Carbon_dioxide_scrubber#Minerals_and_zeolites). For example, quicklime will react with carbon dioxide to form limestone. Large areas of the necessary minerals could be exposed on the surface absorbing CO2. Some mechanism, perhaps wind & grit perhaps geological uplift, would continuously scrub the surface exposing more fresh material to react with the atmosphere.
CO2 is just one problem. You don't want, for example, too much arsenic in the atmosphere. Or even naturally occurring radioactive elements. Accounting for why each and every one of them isn't present at toxic levels gets a little tiresome.
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In sum, unless this is a key part of your story, take the well trod sci-fi road and just don't explain it. There's enough planets in the solar system that humanity will find one desert planet at just the right time in its geological history to happen to have a nitrogen-oxygen atmosphere where the levels of toxic gases aren't too high.
[Answer]
**Water is not necessary for a planet to have an atmosphere.** Planets like Mars have atmospheres without there being water on the planet.
(It is worth noting that Mars' atmosphere is about 100x thinner than Earth's, but that is [due to its lack of magnetic field](https://arstechnica.com/science/2015/11/how-mars-lost-its-atmosphere-and-became-a-cold-dry-world/) rather than any lack of water. In fact, the article just linked states that its thin atmosphere is the reason all the surface water on Mars dried up.)
Even if you need a human-breathable atmosphere, **there is no need for water vapor**. As explained in [this answer](https://worldbuilding.stackexchange.com/a/10457/38818), the atmospheric pressure and relative amounts of different gasses in the atmosphere will have a much greater effect on an atmosphere's breathability than the presence or absence of water will.
As for humans needing drinking water to survive on the planet in the first place, you could have it shipped in from other planets if space travel is available, or have moisture farmers ([sort of Luke's aunt and uncle on Tatooine](http://starwars.wikia.com/wiki/Owen_Lars)) that mine or gather water from the sparse underground sources you mentioned.
[Answer]
High levels of UV radiation from the star around which the planet orbits can *de facto* sterylize the surface, killing any organism which dares to venture on it.
Life can still prosper in the sea, where few meters of water are enough to shield the dangerous radiation.
Active volcanism, filling the atmosphere with ozone killing molecules, prevent the formation of an effective ozone layer.
[Answer]
So, you need to create a bunch of oxygen without much surface water. Free oxygen is pretty rare without biology to constantly regenerate it, due to its extreme reactivity, but there *are* purely geochemical ways to get it. Europa, for example, has a thin atmosphere of mostly oxygen and ozone, due to dissociation of water molecules in Jupiter's radiation environment, and escape of hydrogen in the low gravity.
So, one option would be to posit that the world *had* some surface water in the past, but it was all photo-dissociated over time with hydrogen lost to space, and oxygen left behind. With a terrestrial planet, rather than an ice moon, however, that raises the question of why, even if there is a breathable excess of oxygen left over after it's reacted with everything there is to react with, there *isn't* a crushing, Venus-like amount of carbon dioxide, too! But, as long as that was explicitly acknowledged as an unsolved mystery, I'd be fine with it in a story.
A second option, of course, is that you do have some kind of life regenerating atmospheric oxygen despite the lack of liquid water on the surface. Life in water-filled underground caves isn't going to cut it, because where does that life get the energy to generate oxygen from if it's cut off from sunlight? But if you're willing to have water underground, and water vapor in the atmosphere, we can work with that! You could, for example, have plants with extremely deep tap roots that manage to connect these deep underground water supplies to photosynthetic organs (i.e., leaves) on the surface. I'd expect those to be symbiotic with something like fungi that can help with burrowing through the intervening rock, powered by chemical energy from breaking down said rock. You could also have surface organisms with extremely hygroscopic, water-gathering organs that concentrate water vapor out of the air, allowing for the existence of the occasional macroscopic plant and a thin gruel of "sand plankton scattered over the whole surface.
Of course, a third option is just to declare the whole thing a super-interesting unsolved mystery in planetary science. Combined with the previous option, that gives you practically a whole plot all by itself.
[Answer]
Perhaps it could be explained by exotic silicon-based lifeforms, which are able to photosynthesize and release the oxygen without using water.
Or they have actually absorbed all water up and bound it into their rock/crystal bodies. Even on Earth, many "dry" crystals actually contain water, for example opals (consisting fom silica and water) can contain up to 21% of water by mass.
[Answer]
On earth, the generation of oxygen is dependent on the presence of surface water. In a planet without this abundant water, you will need a different chemical reaction to provide this.
<https://en.wikipedia.org/wiki/Chemical_oxygen_generator>
Sodium or sotassium chorate mixed with iron will burn and generate oxygen. So a geology on this planet that spews chlorates over red iron rich sands, and creates thousands of square miles of shouldering wastelands at the base of mountain rages is one option.
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