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...
