Researchers have identified an impact crater bigger than the city of Paris underneath a kilometer's worth of ice — a little more than a half-mile deep — on the Hiawatha Glacier in northwest Greenland. According to a study published November 14 in Science Advances, the 31-kilometer(almost 20 mile)-wide impact crater was formed by an asteroid that struck Earth within the last 100,000 years and possibly even as recently as 13,000 years ago.