Welcome to the World Factory (Kintsugi Space World Building Thread)

Venus's atmosphere has a higher proportion of deuterium relative to hydrogen than Earth's, which could in theory (though I'm not sure it's actually feasible or worth the investment) be useful for harvesting deuterium as nuclear fusion fuel. Basically, water molecules in Venus's atmosphere (all the water on Venus evaporated due to the runaway greenhouse effect) were broken down by sunlight into hydrogen and oxygen (the oxygen has then pretty much entirely reacted with other stuff). Deuterium is an isotope of hydrogen that's twice as heavy. Both hydrogen and deuterium can escape Venus's gravity, but hydrogen does so more easily and at a higher rate since it's lighter, bringing up the deuterium/hydrogen ratio.

 

Cool!

(I may actually use that-got a story idea involving magitech-based spaceflight. Most things are technological, but nonmagical spaceflight is expensive, so they took the risk and the inconvenience and did magic-based.)

 

I'm not sure if that one setting I have really counts as sci-fi, it's set in the future, it has spaceships and aliens but also magic, and the Earth is flat and space is made of water, and AI uses both technology and magic, and basically it's a mess.
But I've been having lots of fun creating possible planet types for that universe (it helps that gravity isn't mass-based in-universe, and that planets don't form on their own but it's kinda complicated and possibly spoilery), and then figuring out what traits species from each of those planet types would end up with. As an example, species from hollow-sphere planets would have terrible night vision as there would be a huge amount of light at night from the opposite side being lit up.
(A recurring theme would be that each sapient species's homeworld has a very unimaginative name. There's obviously Earth, another is named Home, Here isn't exactly the homeworld of its main species but they've all moved there millions of years ago so no one cares...)

 

One thing I used to read had an entire sect of galactic society dedicated to renaming things.

Turns out, about 90% of species named their homeworld something like Earth.

 

Oh, incidentally-there's an online book somewhere about making plausible aliens. It includes things like listing known oxygen-carrying molecules and their colours, as well as doing a similar thing for known light-capturing molecules that could be useful in alien photosynthesis and what they store the light energy as (chemical or electrical energy).

It also described various possible body plans, eye types (specifically eyes and not, say, biological radio antennae) and their required size, various senses and some example evolutionary backgrounds for a sophont that uses that sense as its standard primary sense, and so on. There's even a section on How To Make Your Bizarre Alien Reproduction Scientifically Plausible, including, iirc, description of a possible three-parent system, where 'mitochondrial' genetic information is supplied by one parent and the other parents each contribute half of the nucleus information each.

Fake Edit: I found the book. Here it is!

Real Edit: Yes, the pages all have links to the previous and next pages. You do not need to open up 50 tabs of everything interesting like I did the first time.

 

Oh, one thing about that book that I forgot: it was written in 1979 and so reflects the social attitudes of the time-so warnings for at least sexism.
It also uses 'bisexual' to mean 'being that requires a single mate to reproduce', rather than 'attracted to two or more genders', in the section on plausible types of alien reproduction.

 

It also probably assumes that of course aliens would use projectile weaponry-aliens might generally use hand-to-hand combat, with frequently moving command posts to prevent anyone on the other side from finishing the complex calculations required for a species that cannot instinctively aim to actually hit something, and any use of projectiles having to be balanced against the risk that the other guys can then calculate how to hit your artillery.

 

@Wingyl U R A GIFT

 

@rats thank you!
More on the aimless aliens: their space combat would involve a mixture of trying to board ships, a lot of moving around to make themselves untargetable to projectile weapons, lasers (used mostly as point-defense, likely), and 'missiles', probably more like flying mines that would hit a ship and explode. The idea of 'throw a thing to hurt what you're attacking' is decently alien to these guys' pyschology!

This also means that you'd have an excuse to have space-combat take place within visual range-much farther out than that and even a guided missile could easily miss, hitting a friendly or going wide due to the entire battle moving.

You'd get ship armoured heavily to allow for ramming, and ships trying to push the ship they've boarded/docked with around to prevent them from being a target, and possibly ships using their exhaust as a weapon. You would not see any projectiles as such.

 

@QuotableRaven Is this thread strictly sci-fi or would, say, Spelljammer things go in here too?

 

I mentioned my weird-scifi-fantasy-mashup setting a bit earlier, so, I guess?

 

Anyway on an entirely different note: description of Witch at the Iron Core's terraforming solution

Witch at the Iron Core is a short story about someone meeting witches, who live apart from society because of a combination of a culture of finding weird new niches and wanting to not cause too much chaos if a magical accident happens.
One witch managed to get to space, and found a large, iron-cored asteroid with a cave system. On the surface, gravity is really low. But, because of the iron core beng so dense, deep in the caves (and at less than 1 g, really huge deep caves formed), gravity's higher. She hailstormed the cave systems with comets, adding in water and air which stayed put due to the gravity gradient and lack of solar wind. It warmed to a decent temperature thanks to compression heating, and stayed that way as heat was conducted from the sunlit surface to the caves.

As a result, she had a vast maze of caverns at livable gravity, temperature, and pressure. It was dark-she had to use massive solar-panel farms on the surface to gather electricity and bring it down to the caves with huge cables-but also enormous, relatively cheap, and there was no need for massive rocket boosters to get off her asteroid; she'd just ride a pressurized train to the airless, low-gravity surface, where it was far easier to send anything valuable she mined or grew back to Earth.

She also didn't have to worry about pressure seals or meteor punctures on anything except her pressurized train, and she had a non-pressurized train for things that didn't need pressurization too. The caves weren't pressurized.

The math apparently holds out.

ETA: This only works on worlds with an iron core and surface gravity too low to hold onto an atmosphere. If it can hold onto an atmosphere for a million years or so (our Moon could keep an atmosphere for millions of years, it just lost it in the billions of years since it formed) then this method would be better as a temporary measure while surface terraforming gets going.

 

I was thinking any planet that isn't earth, and operates more than very slightly different.

 

Okay!

Does anyone here want the link to the Bowering Dragons post?

 

... Okay, I just realized.

Spoiler: Really rambly

Things I already established for that setting:

• Gravity couldn't possibly be based on mass, and artificial gravity can't practically be achieved using spinning since the ships are in water. After realizing this, instead of just going "magic" (that one's for later), I decided that gravitational fields were created by a material that can't be found on the inside of planets (only the bottom of flat planets and the outside of hollow-sphere planet) and creates gravitational forces, which mostly cancel themselves out but typically have a relatively weak pull acting on stuff inside planets, as "outwards-pointing" forces are deactivated by some cosmic law (that may or may not have been put into place by some creator deity to avoid the problem of infinite water pressure), but that can be "aligned" with an electromagnetic field allowing for artificial gravity in ships using only a thin layer of that material. (Gravity conductivity is complicated, but essentially, it goes mostly unaffected through most solids and liquids, is weakened by gases depending on the pressure, and is completely blocked by vacuum and the transparent material that makes up the dome of flat planets and the center sphere of hollow-sphere planets)
• You know what that means? Perpetual motion energy generators. Just carefully place artificial gravity plates in a pattern around an axle, attach a weight off-center to said axle so that it will pick up a spin on its own, strap that to a generator, use part of the energy to power the plates, and here you go, free energy. I then realized this could be how most ships power themselves, and also a possible energy source for space-water-dwelling lifeforms as there's no light or oxygen out there. (Basically, they use the electricity produced from these to electrolyze water into hydrogen and oxygen which are then used for their metabolism, additional minerals and stuff are filtered out of the water. Those lifeforms have a very important role in-universe but I'm not gonna expand on this because, depending on what I do with this setting, it could be spoilers.)
  
• You know what that means? Thermodynamics are a lie. Conservation of energy is an approximation that pretty much only works on planetside environments (especially on Earth where there's some kind of magic-dampening field because probably-spoilers), and energy in the universe is actually steadily increasing. Waste heat would be a problem, at-least-millions of years of civilizations throughout the universe would have noticeably heated the water by now (at least locally, the Here cluster's pretty active), except there's a universal constant for water: 4°C, 1 atmosphere (sea level pressure is the same for every planet because of that, note that local gravity messes with stuff but that's the overall constant). Where does waste heat that diffuses into the water go, then? Well, magic is real, and permeates all of the universe but can vary in intensity depending on location, so, it probably gets converted into magical energy. This is a slow process that, if they let it happen naturally, would be inconvenient for slow-moving ships, but hey, what if it could get accelerated artificially? Maybe there's a reason candles and fire are used so much in magic, and that reason isn't the light.
  
• So, people in this universe now have the ability to get infinite energy, convert waste heat into another type of energy that's easier to take care of (mostly), and, and I just realized that, remove a world's natural gravity by mining the outside and replace it locally with easier-to-manage artificial gravity, since they could actually have the resources for such very-large-scale operations.

Imagine the possibilities this opens. I think I might actually have figured out a possible plot from this.

 

@palindromordnilap slight quibble: a planet with a higher dome/deeper air column would have higher sea level air pressure, allowing for creatures to have a lower wingspan for the same flightweight and stall speed, which also means that a larger creature could comfortably take off and fly without resorting to magic.

 

Yeah, but that planet has openings that lead to space-water-thingy, and the pressure would equalize. I think there might be a way to do that if the planet had deep depressions that weren't filled with water and were way below water level, though.

 

Anyway here's a link to most of the Bowering Dragons stuff, on Roachpatrol's blog because Twocubes seems to have deleted all of it?

The general posts.
And here's a bit of example fiction using it, without the 'sequential hermaphrodite' aspects.

 

And @palindromordnilap something like that actually happened on Earth during the last ice age! The Mediterranean Sea dried up for a few million years, but it was a giant salt flat-if it had been stable for a few million years more, the salt would've been buried under the ground and it'd have gotten the chance to come alive again.

 

Yeah! Something like that but in the future was the setting of Randall Munroe's Time. (Click the pic to see the full thing)