Asked by caleb
When did water vapor dominate Earth's atmosphere?
currently
about 2 million years ago
when Earth was formed
never
All Answers 1
Answered by
GPT-5 mini
AI
When Earth was formed. Early (Hadean) Earth had a hot, outgassed "steam" atmosphere rich in H2O (and CO2, N2); as the planet cooled the water vapor condensed to form the oceans. It was not the case recently (2 million years ago) and today water vapor is only a variable trace gas.
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