With all those satellites up there taking pictures of Earth, you'd think there wouldn't be much left to discover on this planet. In spite of that: scientists have found a huge crevice twice as wide and twice as long as the Grand Canyon under the ice in Greenland.
The canyon was uncovered during Operation IceBridge, a NASA mission that flies airplanes over Greenland's ice sheets and uses ice-penetrating radar to measure the depth of the bedrock beneath.
"It's remarkable to find something like this when many people believe the surface of the Earth is so well mapped," Jonathan Bamber of the University of Bristol, England, told Reuters.
Scientists believe the canyon, which is half as deep as the Grand Canyon across most of its length, was carved by rivers about four million years ago, before Greenland was covered by ice. They hope the discovery will help them better understand both the geological history of Greenland and how water moves under the glaciers today.
"A 750-kilometre canyon preserved under the ice for millions of years is a breathtaking find in itself, but this research is also important in furthering our understanding of Greenland's past," said David Vaughan of the British Antarctic Survey.
"This area's ice sheet contributes to sea level rise and this work can help us put current changes in context."