Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

February 5, 1998
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

A Martian River Bed?
Credit: MGS Project, JPL, NASA

Explanation: This canyon on the surface of Mars appears to have been carved by flowing water. Known as Nanedi Vallis, the terraces and channels visible within the canyon strongly suggest that a river of water once ran here. But the lack of smaller surface channels and other features argue that the valley was formed by a surface collapse. Further images of Martian valley systems will help distinguish the degree to which these processes affected the Martian surface. This image was recorded on January 8th by the Mars Global Surveyor's camera during its 87th orbit of the red planet. The area pictured is about 6 miles wide. High resolution versions of the image show features that are as small as 40 feet across.

Tomorrow's picture: Jules Verne's 170th

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.