In what could turn out to be a landmark discovery in the history of Mars exploration, NASA's Mars Global Surveyor spacecraft returns data that suggests there may be current sources of liquid water at or near the surface of the red planet.

The new images show the smallest features ever observed from martian orbit -- measuring about the size of a sport-utility vehicle. NASA scientists compare the features to those left by flash floods on Earth. The gullies in the images are located on cliffs, usually in crater or valley walls, and are made up of a deep channel with a collapsed region at its upper end. At the other end is an area of accumulated debris that appears to have been transported down the slope. Relative to the rest of the martian surface, the gullies appear to be extremely young, meaning they may have formed in the recent past.

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