Yale Environment 360: A massive gorge nearly twice as long as the Grand Canyon is hidden under Greenland's ice sheet, reports a team of researchers from the U.K, Canada, and Italy. With a width of about six miles and a maximum depth of 2,600 feet, the previously undiscovered canyon is as wide as its Arizona counterpart and nearly half as deep. Flowing water likely carved the canyon long before the formation of the mile-deep ice sheet that has blanketed it for the past few million years. Researchers found the feature using...