Re:Mars likely to have enough oxygen to support life: study
by richardknop on Thursday October 25, 2018 @11:32PM
(#18306578)
Moon has no atmosphere so there is very little protection against cosmic impacts. For Earth, at least, small meteorites burn when falling through upper atmosphere. I am not sure about Mars' atmosphere and how much it protects against impacts.
Finally, I don't think a meteor which wiped out dinosaurs will wipe out humans. We can always use a nuclear bunker and save a few hundred humans with years of food to survive on.