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.

March 20, 1998
See Explanation.  Clicking on the picture will download 
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Mars: Ridges Near The South Pole
Credit: MOC Team, MGS, NASA

Explanation: No, it's not breakfast ... but looking down from an orbiting spacecraft, the odd intersecting ridges covering this area of Mars do present a waffle-like appearance. The cause of the ridge pattern is unknown but it suggests that more complex layered deposits lie below. The south polar region in this Mars Global Surveyor image measures about 8.5 by 12 miles and is spread with a layer of bright, seasonal carbon dioxide frost. Mysterious dark spots which pepper some of the interridge areas are 60 to 300 feet across. Their exact nature is also unknown, but these spots have apparently defrosted early and lack the bright layer of frozen carbon dioxide.

Tomorrow's picture: The Gamma-Ray Sky

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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.