Could developing life on Mars generate an atmosphere?
Just to add a little detail to some of the earlier answers. The gas molecules in a planet’s atmosphere are all in motion. The warmer it is, the faster the molecules move. On Earth at the top of the atmosphere molecules of hydrogen can move so fast that their velocity is greater than escape velocity and so off they go into space. So for this particular reason, we don’t find any significant amount of hydrogen in our atmosphere. On Mars we have a slightly different situation. The planet is significantly smaller than the earth and so the escape velocity is lower. This means that many more molecules are able to escape the planet’s gravitational pull. That’s also why 95% of their atmosphere is carbon dioxide – a heavy and slower moving molecule. All the lighter molecules have already escaped. So if we could find a way of putting oxygen back into the martian atmosphere, it would be a waste of time because it would all slowly escape. Confining the oxygen within a dome may well work, but it is
