Huge Mars Region Shaped by Water, Rover Mission Finds

A false-color image shows Cape St. Vincent, a feature of Mars's massive Victoria Crater. After a dangerous descent into the crater, the Mars rover Opportunity has shown that the red planet once had a network of underground water spread across an area the size of Oklahoma, scientists announced in May 2009. Photograph courtesy Steven W. Squyres

From National Geographic:

Shifting sand dunes on ancient Mars once concealed a network of underground water spread across an area the size of Oklahoma, according to new findings from NASA's Mars rover Opportunity.

In 2004 Opportunity had spotted minerals and blueberry-shaped rocks indicative of ancient groundwater in the Martian crater Endurance.

The robotic explorer has now found similar signs of past water in Victoria, a crater some 3.5 miles (6 kilometers) away.

Opportunity also spotted unique rock layers in the sides of Victoria Crater, which are likely the petrified remnants of ancient sand dunes.

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