NASA Rover Finds Surprising Evidence for Mars’ Watery Past

The strongest evidence yet that ancient Mars was much wetter than it is now has been unearthed by NASA’s Spirit rover.
A patch of Martian soil kicked up and analyzed by Spirit appears to be rich in silica, which suggests it would have required water to produce.
Chemical analysis performed by the rover’s robotic arm-mounted science instruments measured a composition of about 90 percent pure silica — a material commonly found in quartz on Earth — for the bit of Martian dirt, said mission scientists, who first heard of the find during a teleconference.
“You could hear people gasp in astonishment,” said Steve Squyres, principal investigator for NASA’s twin Spirit and Opportunity rovers at Cornell University in Ithaca, New York. “This is a remarkable discovery.”