Martian sand dunes

March 08, 2014 - 12:42:47 am

Mars’ northernmost sand dunes emerge from their winter cover of seasonal carbon dioxide (dry) ice, in this image captured by the HiRISE camera aboard Nasa’s Mars Reconnaissance Orbiter. The dark splotches are places where ice cracked earlier in spring, releasing sand. Soon the dunes will be completely bare and all signs of spring activity will be gone.