Mars Images Provide Evidence of Big Long-Gone 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 researchers believe water once flowed and apparent beach remnants surrounding a basin.

Dubbed the Shalbatana lake for the valley it was located in, scientists believe it was about the size of Lake Champlain that borders the states of New York and Vermont.

The findings were published in this week's Geophysical Research Letters.

Lead researcher Gaetano Di Achille of the University of Colorado at Boulder estimates the lake formed 3.4 billion years ago, an era of the planet that scientists generally have believed was cold and dry. The lake probably evaporated or froze over, he said.

Cornell University Mars expert Jim Bell called it a neat find, but he said he would like to see other data besides images to support there was a lake.