Posted: Sat, May 24, 2008, 12:53 PM ET (1653 GMT)

Scientists analyzing data collected by one of NASA's twin Mars rovers confirmed this week the discovery of silica deposits like those made by hot springs on Earth. In a paper published in the journal Science, scientists said an unusual bright patch of soil uncovered by the rover Spirit as it dragged a malfunctioning wheel across the terrain is made of nearly pure silica, confirming an initial analysis of the finding announced last year. The production of silica requires large amounts of water, and on Earth takes place at hot springs like those at Yellowstone, suggesting that similar features may have once existed on Mars.