spacetoday.net: Curiosity finds new evidence Mars was once habitable

Posted: Wed, Mar 13, 2013, 8:08 AM ET (1208 GMT)
MSL first rock sample, Feb 2013 (NASA/JPL)

Analysis of a rock sample by NASA's Curiosity Mars rover has given scientists new evidence that Mars once had the right conditions to support life. Scientists reported Tuesday on the first rock sample collected by Curiosity, of a rock dubbed "John Klein", collected by the rover last month. They found that clay minerals make up at least 20 percent of the sample; such minerals form in the presence of relatively fresh water, and the presence of calcium sulfate indicates that the water was relatively neutral or mildly alkaline. The mix of oxidized and non-oxidized chemicals could also have provided an energy source for any microorganisms that lived there early in the planet's history, although Curiosity found no evidence of past or present life.