Seen at New Scientist:
A new analysis of pictures taken by the exploration rover Opportunity reveals what appear to be small ponds of liquid water on the surface of Mars.[...]
If confirmed, the existence of such ponds would significantly boost the odds that living organisms could survive on or near the surface of Mars, says physicist Ron Levin, the report’s lead author, who works in advanced image processing at the aerospace company Lockheed Martin in Arizona.[...]
The imaging shows that the areas occupy the lowest parts of the terrain. They also appear transparent: some features, which Levin says may be submerged rocks or pebbles, can be seen below the plane of the smooth surface.