Posted: Thu, Dec 7, 2006, 7:47 AM ET (1247 GMT)
Planetary scientists have discovered evidence that liquid water may have flowed on the surface of Mars, albeit briefly, within the last several years. Scientists said Wednesday that images of gullies in crater walls in the planet's southern latitudes, taken seven years apart, showed flow features in the new images not seen in the older ones. Those features are thought to be debris left by water emerging from the side of the crater and flowing downhill for a short time before freezing or evaporating. The gullies themselves were previously believed to be created by water from an unknown subterranean source, but it wasn't clear if the mechanism that created the gullies was still active. Other scientists noted that the features seen in the images could have been created by avalanches of sand or dust, without any water present.

Related Links:

•  SPACE.com article
•  Washington Post article
•  San Francisco Chronicle article
•  AP article
•  NASA press release