Astronomy Picture of the Day

Explanation: Scroll right and journey for 300 kilometers over Terra Sirenum in the cratered highlands of southern Mars. The infrared view, 32 kilometers wide, was recently recorded by the THEMIS camera on board the orbiting Mars Odyssey spacecraft. Beginning at the north (left) edge, the scene sweeps across the floor and over the rim of Koval'sky Crater. Continuing southward (right) of the crater's rim are lava flows exhibiting fractures and numerous smaller impact craters. The infrared image was made in daylight hours, so sun-facing slopes are still warm and bright while shadowed areas are cool and dark. But rocky regions also tend to remain cooler and darker than their surroundings, likely corresponding to the dark blotchy terrain along the Koval'sky Crater floor and dark rings of rocky ejecta surrounding some of the smaller craters.