A new investigation of clay-like material found on the Martian surface suggests the planet did not have free-flowing water on its surface.
For years, evidence that Mars once held flowing liquid water - a key ingredient for life - has been pouring in.
NASA's surveys have shown ice-locked water at the poles, visual evidence of valleys apparently carved by water millions of years ago, and clays which appear to have formed in free-flowing water.
But the new theory by authors at Caltech University and printed in Nature Geoscience, suggests the clay may have been formed by lava which - at a temperature of 1,500C - would have been much less hospitable to life.
Source: Daily Mail. Read full article. (link)