First post, long time lurker. Supposing that mankind were to first choose the Moon as the celestial body for colonisation (no questions at this point, those in favour of Mars pretend for a second it has some sort of life on it!), how would we go about creating a significant atmosphere on the Moon? Lack of significant magnetic field aside, what short and long term problems would be faced? Is the Moon a large enough body to hold onto an atmosphere conducive to life as we know it? And if so, what is the lower bound for a planet/moon in terms of mass for a significant atmosphere? Apologies for all of the questions, look forward to a good discussion getting going.