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.

2001 March 27
See Explanation. Clicking on the picture will download the highest resolution version available.

Swiss Cheese-Like Landscape on Mars
Credit: Malin Space Science Systems, MGS, JPL, NASA

Explanation: Why do parts of the south pole of Mars look like swiss cheese? This little-understood landscape features flat-topped mesas nearly 4 metres high and circular indentations over 100 metres across. Since this swiss-cheese topography is unique to the polar cap covering southern Mars, exogeologists speculate that mesa composition might be high in frozen carbon dioxide (dry ice). Additionally, dry ice might have had a role in this strange landscape's creation. In the above picture, the Martian surface is illuminated by sunlight from the upper right. The above picture was taken in August 1999 by the robot Mars Global Surveyor spacecraft currently orbiting Mars.

Tomorrow's picture: Black Hole Universe

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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.