Recent discoveries of living organisms in conditions where once life wasn't thought to be possible has greatly expanded our scope when looking for life in the Universe, as environments that should be sterile and dead could instead reveal to be teeming with life. It's important to keep in mind that, most probably, life on Earth didn't appear in such conditions, but just adapted to them after arising in a more comfortable environment; still, this leaves the possibility of life on worlds that once were more hospitable (such as Venus or Mars) or subjected to panspermia.