verified by Nature and the Washington Post
@RobertCousineau living off of earth and not the result of near term spread from earth for example from a mars probe
If ancient panspermia it counts
Last 1m years perhaps? Or maybe even more
Example: during Sputnik era an earth bacteria spread onto mars. That is not alien
Example 2: 1b years ago a meteor knocked an earth bacteria to mars where it survived and evolved and now is a new thing. This is a hard case I'm inclined to say YES
Things that go into being truly alien: long time of separation, very different from us
Cases
Example3: a super weird alien life form has secretly lived on earth, which evolved elsewhere totally separately. It's been here for a super long time. That still feels alien even though its life history intersects earth
yeah it's kind of tough cause I've never thought about it. If we are forks of the same panspermia thing but they're nearly totally diff and in all ways appear alien, it's not that useful to say they're "not fully separate". But if we find a weird bacteria left over in space from sputnik that's surviving, thats not reasonably "found alien life". But it's hard to find a perfect line.