image: This is a false-color image of dark sand dunes at high northern latitudes on Mars that are covered seasonally by a layer of condensed carbon dioxide (dry ice), shown in this image. When the sun rises in the spring the ice begins to sublimate. Gas flow from the bottom of the ice layer propels sand from the dunes out through cracks to the top of the ice and down the dune slipface. This image relates to an article that appeared in the Feb. 4, 2011, issue of Science, published by AAAS. The study, by Dr. C.J. Hansen of Planetary Science Institute in Tucson, Ariz., and colleagues was titled, "Seasonal Erosion and Restoration of Mars' Northern Polar Dunes." view more
Credit: Image courtesy of NASA/JPL/University of Arizona