Scientists Discover Immense, 460-Mile-Long Canyon Under Greenland's Ice Sheet

Using data from NASA's Operation IceBridge and other airborne campaigns, scientists led by a team from the University of Bristol have found that an enormous, 460-mile-long canyon runs from near the center of Greenland northward to the fjord of the Petermann Glacier. One of IceBridge's scientific instruments, the Multichannel Coherent Radar Depth Sounder, can see through vast layers of ice to measure its thickness and the shape of bedrock below. Hidden for all of human history, this immense feature is longer than the Grand Canyon and is thought to predate the ice sheet that has covered Greenland for the last few million years.