Another theory that just came to me is that Hitoshi was maybe sent across the Milky Way to the other end of the galaxy, like through near the middle (where super massive black hole apparently resides). And well... that would take a very long time, but the galaxy also rotates in the mean time too. The time it would take for Hitoshi to reach the other side, perhaps it would be enough time for the galaxy to rotate and have the solar system end as his destination.
We're talking millions of years here, and enough for Kemos to evolve?
This came to me when I was reminded of this trivia that our solar system during the era of the dinosaurs was on the other side of our galaxy relative to us, today.