Submission + - NASA's "Opportunity" Rover Finds New Evidence For Once-Habitable Mars (space.com)
nedko.m writes: NASA's Mars rover 'Opportunity' found clay minerals in an ancient rock on the rim of the Endeavour Crater on Mars. The discovery suggests that neutral-pH water — slightly salty, and neither too acidic nor too alkaline for life — once flowed through the area, probably during the first billion years of Martian history. Opportunity's latest discovery fits well with one made recently on the other side of the planet by the rover's bigger, younger cousin Curiosity, which found strong evidence that its landing site could have supported microbial life in the ancient past. Such observations could help scientists map out Mars' transition from a relatively warm and wet world long ago to the cold and dry planet we know today
