11 March 2005
Vol 307, Issue 5715

About The Cover

Cover image expansion

COVER False-color image of the north polar region of Mars in summer, showing its composition as inferred by the OMEGA/Mars Express visible and near-infrared imager. The cap is made of water ice (blue) mixed with mineral grains (shades of gray), with dark zones of ice-free minerals within which vast areas of gypsum (red), a hydrated sulfate, have been discovered. See page 1574. [Image: © Institut d'Astrophysique Spatiale]