NASA’s Mars Reconnaissance Orbiter captured this intriguing view of “corduroy” sand dunes rippling across the permanent polar cap of Mars. The dunes “march across a fabric of patterned ground,” according to a NASA caption that explains “at this time of the Martian year the dunes are free of the seasonal dry ie that forms a temporary cover every winter.” Launched in 2005, the MRO braked into orbit around the red planet in 2006 to study the history and distribution of water. Its High Resolution Imaging Science Experiment, or HiRISE, which took the image seen here, is one of the most powerful cameras ever launched aboard a planetary spacecraft.
