I WAS EXPECTING AN EARTH-SHATTERING KABOOM: The world’s biggest, oldest impact crater hollowed out Greenland three billion years ago. “It’s not confirmed yet, but a potential crater site in Greenland would be the oldest, biggest impact ever observed on Earth. The original asteroid would have been about 18 miles across – that’s about half the length of Rhode Island, which is pretty damn huge by asteroid standards – and the crater it initially created would have been nearly 375 miles wide and over 15 miles deep. While we’ve seen evidence of impacts on that scale elsewhere in the solar system, we’ve never seen anything like this on Earth.”