Spotted Arabia Dunes

Sand dunes mottled with blue-black spots lie next to a central hill within an unnamed, 120-kilometer-wide crater in eastern Arabia on Mars taken by the Thermal Emission Imaging System instrument on NASA's Mars Odyssey orbiter in 2003 and 2004. False colors depict the nature of the ground surface: Areas with bluish tints have more fine sand at the surface, while redder tints indicate harder sediments and outcrops of rock.