By Nadia Drake
It’s no secret the early Earth took a beating from above, but now it seems the planet sustained a longer bombardment than initially thought.
Scientists used to think this pummeling — a spike of violent impacts during the lunar Late Heavy Bombardment – lasted several hundred million years at most. But new simulations that incorporate an extended asteroid belt, combined with evidence pulled from the Earth’s own rocky record, suggest Earth’s pummeling lasted for billions of years, two teams report online April 25 in Nature.
“It seems highly likely that these impacts affected the Earth’s biosphere in profound ways,” says planetary scientist and study coauthor Bill Bottke of the Southwest Research Institute in Boulder, Colo.