More evidence of water on Mars

This story is extra cool, b/c it's an example of serendipity - they discovered the evidence b/c the rover's wheel is broken! Below is an excerpt and link to the full story.

NASA Rover Finds Surprising Evidence for Mars' Watery Past
SPACE.com
May 21, 2007

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."

This discovery came about unexpectedly as the result of a mechanical failure.

Both Spirit and its twin rover Opportunity completed their original three-month missions in April 2004, and are aging. One of Spirit's six wheels no longer rotates, gouging a deep impression as it drags through soil. That scraping has exposed several patches of bright soil, leading to some of Spirit's biggest discoveries in its Gusev Crater exploration site, including the most recent find.

http://news.yahoo.com/s/space/20070521/sc_space/nasaroverfindssurprisingevidenceformarswaterypast