Picture of the Day: Minerals Deposited by Water on Mars
By Rebecca J. Rosen
New pictures from NASA's Mars Exploration Rover Opportunity show a bright vein of a mineral deposit, believed to be gypsum. "This tells a slam-dunk story that water flowed through underground fractures in the rock," said Steve Squyres, a scientist at Cornell University. "This stuff is a fairly pure chemical deposit that formed in place right where we see it. That can't be said for other gypsum seen on Mars or for other water-related minerals Opportunity has found. It's not uncommon on Earth, but on Mars, it's the kind of thing that makes geologists jump out of their chairs." The above image appears in "approximate" true color -- what NASA scientists believe the scene would look like if humans could go to Mars and see it with their own eyes.