The Thermal Emission Imaging System (THEMIS), a special camera on NASA's Mars Odyssey orbiter, shows the cratered landscape of Terra Sirenum on the red planet.

This false-color image shows cooler areas in blue, and warmer areas in orange and yellow hues. 

Scientists believe the temperature differential results from newer lava flows creating sheets of warmer areas of rock and compacted sediments, contrasting with older loose dust and sand, which doesn't retain heat as well.

--NASA/JPL-Caltech/ASU and SPACE.com Staff

Credit:NASA/JPL-Caltech/ASU