NASA's Mars Global Surveyor shows the 'swiss cheese' pattern of frozen carbon dioxide on the south polar residual cap.

MGS MOC Release No. MOC2-337, 21 April 2003

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the "swiss cheese" pattern of frozen carbon dioxide on the south polar residual cap. Observation of these materials over two Mars years has revealed that the scarps that bound the mesas and small buttes are retreating-the carbon dioxide ice is subliming away-at a rate of about 3 meters (3 yards) per Mars year in some places. The picture covers an area about 900 m (about 900 yards) wide near 87.1°S, 93.7°W. Sunlight illuminates the scene from the upper left.

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