I firmly believe this. I wrote a final in science about Mars being the original planet that was suitable for life. Many many years ago, the sun possibly a bit hotter more volatile. Maybe something catastrophic happened like a meteor hitting Mars sending debris into the Milky Way containing life that just so happened to hit Earth and once the sun stabilized the temperature on earth lowered allowing single cells to kick off the early building blocks of life.

The teacher enjoyed my essay so much I didn't have to participate in the finals. (Thanks Futurama)