News FocusLunar and Planetary Science Conference

Asteroid Model Shows Early Life Suffered a Billion-Year Battering

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Science  15 Apr 2011:
Vol. 332, Issue 6027, pp. 302-303
DOI: 10.1126/science.332.6027.302-a

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Life was hard on early Earth, but geologists and planetary scientists at the Lunar and Planetary Science Conference reported evidence of even more biotic stress several billion years ago: a prolonged pummeling by huge asteroids that would have dwarfed the one that killed off the dinosaurs. The known impact beds suggest that there was a large impact every 40 million years on average in the Archean eon—the time from 3.8 billion years ago to 2.5 billion years ago—not every 500 million years, as has lately been the case.