Mars rover finds signs of microbial life

Nasa says its Mars rover Spirit has discovered “the best evidence yet” of a past habitable environment on the planet’s surface. Spirit has been exploring a plateau called Home Plate, where it discovered silica-rich soil in May.
Researchers are now trying to determine what produced the patch of nearly pure silica – the main ingredient of window glass.
They believe the deposits came from an ancient hot-spring environment or an environment called a fumarole, in which acidic steam rises through cracks.
On Earth, both of these types of settings teem with microbial life, said rover chief scientist Steve Squyres.