The early Earth was hit by huge asteroids 10 times more often than anticipated.
Earth has been massively bombarded by asteroids, but new analysis shows that the number of these impacts may have been 10 times more.
The new study is also looking at what impact asteroids might have on Earth’s evolving near-surface chemistry.
The authors of the work note that asteroids had a significant impact on the chemistry of the earth’s surface and the ability to support life, for example, one such collision led to the extinction of dinosaurs.
Impact craters from such collisions can be seen on the Moon and other rocky planets, but atmospheric weathering and plate tectonics tend to mask any direct evidence of such events.
However, their evidence can be traced back to ancient rocks, in particular the presence of spherules: strong impacts ejected molten particles and vapors, which then cooled and fell to the Earth, where they turned into spherical vitreous particles. The stronger the impact, the more of these particles would spread from the impact site.
Using this approach, the authors note, they found that current models grossly underestimate the number of known asteroid impacts.