Would they always need earth to be habitable?
Because if they somehow managed to terraform and colonise another planet like mars, wouldnt they just make earth so uninhabitable that the rest of us would be forced to go where they are? (Prolly as slaves)
What?! When was that?
A while ago.
Fr? Tf
The kind of atmosphere a planet can have in the long term depends on having enough gravity to keep gas particles from floating off into space. Mars’ gravity is smaller than Earth’s, which means that even if it had oxygen, that oxygen would be lost over time. Mars likely once had a dense atmosphere heavy in carbon dioxide, it wasn’t lost in one specific event, but gradually losing it over a long period of time.