Posted: Fri, Nov 14, 2003, 7:29 AM ET (1229 GMT)
Images of what appear to be alluvial fans of debris on the surface of Mars have led some planetary scientists to conclude that ancient Mars had rivers that lasted for a significant period of time. Images dating back to the Viking missions in the 1970s shows what appeared to be ancient river channels, but scientists debated whether those were filled with water for a long period of time or were carved out by brief, intense floods. Scientists examining images taken by NASA's Mars Global Surveyor spacecraft show what appear to be delta-shaped fans of debris in an unnamed southern crater hardened into curves of rock. Scientists think are evidence of meandering river channels, something that would only happen if water was flowing for more than a short period of time, creating a lake in the crater.

Related Links:

•  NASA press release