This Acasta gneiss is a sample of the oldest known rock in the world. It was found in northwest Canada and is approximately 4 billion years old, just 500 million years younger than the estimated age of the Earth. | SSPL/Getty Images

Earth’s Oldest Rocks Were Likely Formed in the Crucible of a Meteorite Impact

The 4-billion-year-old rocks of Canada’s Acasta River were formed in temperatures much hotter than Earth’s core.

Published On 09/11/2018
1:20 PM EDT