3 December 2004
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an exposure of finely-detailed layers in the martian north polar region. The polar ice cap, which is made up of frozen water (whereas the south polar cap is mostly frozen carbon dioxide), is underlain by a thick sequence of layers. Some have speculated that these layers may record the history of changes in martian climate during the past few hundreds of millions of years. This picture is located near 86.0°N, 30.2°W, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.