Sunday, October 2, 2011
APOD 1.5 -- Start of the Martian Summer
At the end of each Martian summer, the ice on the south pole begins to defrost as the weather gets warmer, causing the dry ice to sublimate into Carbon-Dioxide. The walls of the thawed ices pits are of an unknown composition, and it is likely that they were formed by either water or lava. This image was captured by the Mars Reconnaissance Orbiter, which was launched in 2005 to search for evidence of water on Mars. It took the orbiter 13 months to reach its science orbit at which point its water detection instruments were switched on. Over the next few months, the Martian weather will begin to get colder until the atmosphere again begins to freeze into dry ice.