Despite its cold and arid surface, Mars displays signs of recent liquid water activity in numerous places, bolstering theories that simple life forms could have emerged on the red planet, scientists said Wednesday. Researchers detected evidence of past water seepage while looking at images snapped by the Mars Global Surveyor spacecraft, sources said. The photos suggest the water activity occurred at various locations and elevations, a senior space agency scientist said. Scientists have long thought Mars' surface coursed with water billions of years ago, based on evidence of liquid erosion and signs of ancient channels and seas. But the water all but disappeared as the planet cooled and its atmosphere thinned.
Water is known to exist today as ice in the northern polar cap and as vapor in faint clouds.
But vast quantities could remain trapped under the surface, according to planetary geologists. Many theorize that such groundwater remains in a frozen state. But the Surveyor images suggest that recent underground volcanic forces have heated water into a liquid state, said a scientist who has looked at the report. The report will be published in the June 29 issue of Science magazine. Groundwater would likely turn into vapor or ice soon after it bubbled to the surface.