Oh! Oh! I’ve thought about this!
It would make more sense to build habitat craters, dug deep enough into the ground that the surface air pressure would be at a level tolerable to humans (even if the atmosphere mixture was bad, being able to simply wear a respirator instead of an entire suit would be huge).
I did some math once, on Mars a crater several miles deep would have a pressure similar to Earth’s surface.
I think the Moon was like 40 miles or something, which at that point would probably run into other problems that I am not smart enough to worry about lol
You won’t even need to dig the hole! If you do this before much other habitations on the planet, you could precisely direct astroids to impact the same place to dig the whole for you. I think Cody’s Lab did a video about it, but I can’t find it right now.
Awesome answer but could you still answer the question for those still curious?
Well the craters could be domed off to maintain a healthy Earth-like atmosphere, and because the pressure is maintained by the depth of the crater the dome itself wouldn’t actually have to hold the air pressure in against a low pressure environment.
Also, presumably the reason a habitat would be planet-side is to take advantage of mineral resources, so a lot of digging will happen anyway.
The low-gravity planets/moons we have access to have rather harsh radiation environments, too, so neither. Dig into the ground. You would put a bunker or dome up on the surface for observations and airlocks, but it’d be foolish to live that exposed on a surface without a deep well of atmosphere & Van Allen belts.
Now I know next to nothing about it, but listening to the Art Bell Tape Vault and other alien/conspiracy theory/etc podcasts I know that one of the big theories popular amongst some in the UFO community is that the intelligence behind UFOs is some kind of breakaway civilization that survived one of the last cataclysms on Earth and kept advancing.
Low gravity planets are probably small planets with a low escape velocity, so they probably can’t hold a thick atmosphere. Domes are better at maintaining internal pressure.
If you take two planets of the same density, but one with a radius that’s twice as large, the mass and volume is going to be 8 times higher (2³), while the radius is only going to be twice as high.
The gravitational field is inversely proportional to the distance squared…
But escape velocity is only inversely proportional to the distance… This means that if you made a really dense, small planet where the surface gravity is identical to earth, it would still have a much lower escape velocity, so the gases are going to be likely to escape due to atmospheric escape; when a molecule is moving at a higher velocity than the escape velocity of the planet.
Thus, a smaller planet with the same surface gravity would lose it’s atmosphere due to atmospheric escape at a much higher rate than a larger planet.
You can take it the other way, and have a hypothetical megaplanet that has a lower density, but because of it’s enormous size, it still has an earth-like surface gravity, but it’s escape velocity could be so high that a hypothetical civilisation could be stuck there and might never be able to escape their planet’s gravitational binding energy, thus never becoming an interstellar civilization. In theory, a large enough black hole could have an event horizon where the acceleration is the same as on our planet’s surface, but the escape velocity would literally be the speed of light and people would never be able to leave.
First of all, domes in general aren’t a great idea except for maybe greenhouses - at least on planets in our system. NASA and ESA have done some cool concept experiments as to what pressurized architecture could look like, and it’s a lot more like a cross between a space station module and Earth architecture.
Second - assuming we’ve adapted/evolved to the low gravity, skyscrapers are probably the way to go. That said, if we’ve adapted that heavily we probably have similar adaptations to the atmosphere etc. - in which case architecture would probably be similar to Earth architecture, but able to build higher assuming the same materials.
But if we were trying to colonize a low-gravity world, we’d have to use an orbital station with centripetal-force “gravity” and only research stations on the surface, with a science crew rotation every 6-12 ish months to prevent bone loss.
This is actually the plan for the Moon and then Mars - use Gateway as a station to resupply and host crew rotations for Moon and Mars missions, and eventually to support long-term habitation. But until such a station exists, Lunar Gateway will be used for a waystation for crew rotations between the Moon and Earth.
Space engineering is about to become a very high demand field, on the absolute frontier of human exploration…
It depends on whether you need to contain atmosphere.
Kim Stanley Robinson’s Mars Trilogy goes into exquisite detail about the tradeoffs between different construction methods on Mars and other worlds in our solar system.
