But all of its atmosphere leaked out into space
Wasn’t that because Mars isn’t heavy enough?
2 points
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Well, its small mass certainly contributed to it losing heat more efficiently. But Mercury (much less massive than Mars) and Ganymede (around the same mass as Mars) both have a magnetic field, so there are a lot of other factors at play. Something to do with a change in the chemical composition of Mars’ mantle, and the possible lack of plate tectonics, I’m not so familiar with the causes though.
