Eli5: how does the earths atmosphere work? E. G how does the oxygen not fade away into the cosmos

Question

I’ve had a conversation with a guy that claimed “it’s a myth”. An obvious face-palm, I know, but I realized I’d like to know.

In: 71

Answer 1

It actually does. The sun actually blows some away. It’s gravity that holds it down but the magnetic field of earth actually helps protect our atmosphere. It’s actually a major problem for space flight and Martian colonization.