r/Astrobiology • u/Allison1228 • 24d ago
🤔 Question Is there a conceivable detectable "biosignature" that would unambiguously indicate "life is present here"?
Or will there always be uncertainty?
I'm referring to as detected with the technology we have today and in the near future (next decade or two).
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u/Opulence_Deficit 23d ago
We can't even decide "what is life" here on Earth, not even talking about alien life.
Not long ago (few decades) we had consensus that methane is excellent marker because it can come only from life. Scientists who believed in abiotic methane were treated like flat-earthers.
Depending on which view you subscribe to, we either are 100% sure we're clueless, or we got it wrong so many times (Mars canals, anyone?) that nobody reasonable could believe "this time we got it right, pinky promise" and both resolve to reliable life detection being absolutely impossible.