The age of discovery isn't over yet. A colossal canyon, the longest on Earth, has just been found under Greenland's ice sheet, scientists announced this week in the journal Science.
"You think that everything that could be known about the land surface is known, but it's not," said Jonathan Bamber, lead study author and a geographer at the University of Bristol in the United Kingdom. "There's still so much to learn about the planet."
The great gorge meanders northward from Summit, the highest point in central Greenland, toward Petermann Glacier on the northwest coast, covering more than 460 miles (750 kilometers). Researchers think the ravine could be even longer, but they don't yet have the data to prove where the canyon peters out deep under the interior ice sheet. "It may actually go farther south," Bamber told LiveScience's OurAmazingPlanet. (See Photos of Mega-Canyon Under Greenland Ice Sheet)
The broad chasm is up to 2,600 feet (800 meters) deep and 6 miles (10 km) wide, similar to America's Grand Canyon in scale, the researchers said. The distinctive V-shaped walls and flat bottom suggests water carved the buried valley, not ice, Bamber said. Though it is not the world's deepest canyon, it's the longest, handily besting the 308-mile-long (496 km) Yarlung Tsangpo Grand Canyon in China.