BBC: Mars robot unearths microbe clue

BBC NEWS | Science/Nature | Mars robot unearths microbe clue: "Nasa says its robot rover Spirit has made one of its most significant discoveries on the surface of Mars. Scientists believe a patch of ground disturbed by the vehicle shows evidence of a past environment that would have been perfect for microbial life. The deposits were probably produced when hot spring water or steam came into contact with volcanic rocks. On Earth, these are locations that tend to teem with bacteria, said rover chief scientist Steve Squyres."