Web Special: Clay magic on Mars

NASA’s Mars Reconnaissance Orbiter has completed a week of picture taking from as low as 300 kilometers above the Red Planet’s surface. This scene is a composite produced from three images that were taken using infrared, red, and blue-green filters.

Astronomers suspect that the ground here contains clay, which forms only where there’s abundant water for long periods. The variations in color reflect different minerals in the clay. The area pictured is near the Mawrth Vallis, a channel cut by floodwaters slightly north of the planet’s equator.

The craft will soon lose communication with Earth for several weeks as Mars passes behind the sun. On Nov. 7, after the planet reappears, Orbiter will begin its main data-gathering mission. See the Oct. 21 issue of Science News for another image from the Mars Reconnaissance Orbiter.