Terraform the moon. I want to look up to the skies and see a green moon every night. It is unfortunate we haven't spent a dime settling a moon base and studying the possibilities of creating a livable atmosphere on the moon being just a couple days away.
The maths are interesting. I tried figuring out how thick the atmosphere would need to be, but I kept coming up with ludicrous answers --- one model I tried, in order to get breathable pressure on the surface, the atmosphere had to extend out at least two lunar radii. That would have made the moon just a simple white fuzzy ball in the sky, and you'd never see the sun from the surface.
I need to get back to this and see if I can improve the models a bit.
This is excellent! I did not see any reference to the math. So you are saying, if there was an atmosphere that extended to two moon radii, it will stay with the moon and you will have breathable pressure on the surface?
I couldn't make the maths work, so the atmosphere in the pictures was picked solely to make them look good.
The moon's far too small to hold an atmosphere for geological periods of time; in real life it'll all leak away into space. The reason why my model produced such a huge atmosphere was that the more air I added, the deeper the atmosphere got; but the further away from the surface the lower the gravity, so I ended up with diminishing returns. Once you're a lunar radius away from the surface your air weighs only half as much as it did on the surface, so now you need even more, which makes the atmosphere even thicker, which means the portion up high weighs even less...
If you start from the premise of domed cities, then the expansion pattern pretty obviously says glassing in the entire moon is the natural end result of that. The lower-gravity drastically reduces your requirements, and the regolith can be fused into glass and moved a 100m up to form the roof.
It also reduces your energy requirements long term because you can use mirrors at the roof-level to reflect sunlight around the entire surface to avoid a 2-week night-time cycle, and adding an atmosphere means you "naturally" can keep it warm.
Since the pressure would be exerted outwards, the entire structure would be mostly self-supporting - requirements would lean towards figuring out how to repair it in the event of meteorite impacts, but self-sealing plastic layers could be developed.
Well, impacts. I suppose that a vertical hit at interplanetary speeds (or earth-orbit speeds, that high up) will leave a nicely clean hole, but think of the enormous cut made by something coming in on a trajectory that would slingshot close to the moon surface if the bubble wasn't there.
Sure, with technology indistinguishable from magic you could still do it, but i don't known if there would still be much incentive for building the bubble left in that case.
