We were based on MARS initially.
We thought of being multi-planetary species.
We looked around and found EARTH to be habitable or rather worth surviving.
We sent few people to EARTH to start a new civilization.
We soon fucked up MARS with nuclear war.
We left MARS brethren stranded on EARTH with no hope from the home planet.
We eventually grew and civilized on EARTH.
We thought of being multi-planetary species again.
We looked around and found MARS to be habitable or rather worth surviving.
And we are going to send few people to MARS to start a new civilization.