gwern comments on New Year's Predictions Thread - Less Wrong

18 Post author: MichaelVassar 30 December 2009 09:39PM

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Comment author: gwern 19 August 2010 08:49:45AM 0 points [-]

Is it possible to have liquid water without life? I remember reading that an oxygen atmosphere was quite impossible, but am not sure about liquid water.

Comment author: Unknowns 19 August 2010 10:28:57AM 0 points [-]

There could be an oxygen atmosphere without life for a short period of a planet's history (I'm not sure how long.) It wouldn't be possible for it to remain permanently.

According to our evidence, Mars had liquid water for a very long period, but no one considers this to be proof that there was life there.

Comment author: gwern 20 August 2010 09:03:34AM 0 points [-]

According to our evidence, Mars had liquid water for a very long period,

I went to check this - maybe liquid water is a short-term enough thing that its mere presence is still weak evidence for an active biosphere, but apparently one timeline puts liquid water as present in large quantities for >600 million years. Bleh.