Honestly, we don’t know that life didn’t evolve more than once here. What happened 3.5 billion years ago is anybody’s guess. Perhaps there were competing biological paradigms, proto-bacteria using different basic designs. Who the hell knows.

I guess the part that makes it cool, is maybe you don’t need carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulphur. Maybe you just need atoms to play the “roles” these elements play. That would make a huge difference in where we look for life elsewhere.

It’s inevitable that life exists elsewhere. It’s ridiculously unlikely for it not to. this just means maybe its not so specific about conditions as we thought.