Impact crater 19 miles wide found beneath Greenland glacier
An illustration of the ice-filled crater discovered in Greenland. Photograph: Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark
A huge impact crater has been discovered under a half-mile-thick Greenland ice sheet. The enormous bowl-shaped dent appears to be the result of a mile-wide iron meteorite slamming into the island at a speed of 12 miles per second as recently as 12,000 years ago.