Quote:
Originally Posted by jeff_wilson
That's not the whole story; pre-life Earth did not have a breathable atmosphere or surface water and you can see how Venus has a similar distance from the sun but a very different condition from earth's current one.
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We owe our present concept of life to the great oxygen event. But I'm not sure it was necessary to prevent a runaway greenhouse event at Earth distances.
I thought surface water coalesced very early, but that it's hard to absolutely prove without known hydrates and oxides from later in the geological record. Blasted tectonics messing up the data. ;)