New Images May Show Ancient Martian Lake

New images suggest Mars had a sizable lake on its surface billions of years ago, further evidence that the planet had a watery past. Images snapped by NASA's Mars Reconnaissance Orbiter reveal a 30-mile-long canyon where water once flowed and beach remnants surrounding a basin. Dubbed the Shalbatana lake for the valley it's located in, scientists believe it is about the size of Lake Champlain.

The lead researcher estimates the lake formed 3.4 billion years ago at a time when the planet was believed to be cold and dry. It probably evaporated or froze over, he said. A Cornell University Mars expert called it a neat find, but he said he would like to see other data besides images to support the notion of a lake. (More Mars stories.)