Big asteroid slammed into Greenland just a few million years after the dinosaurs died out

Hidden under Greenland’s thick ice sheet, scientists found what they thought was the scar of an asteroid impact perhaps just thousands of years old, fresh enough that humans were already on the scene.

But after several years of additional research, two separate teams of scientists have determined its age to be far older: 58 million years. Researchers from the University of Copenhagen’s GLOBE Institute discovered the structure, which they suspected to be a massive 20-mile-wide (31 kilometers) impact crater, in 2015 beneath Greenland’s thick Hiawatha ice sheet