Description: January 24, 2008 - Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite captured this image of Tenoumer Crater in Mauritania, which lies deep in the Sahara Desert. Nearly a perfect circle, it is 1.9 kilometers (1.2 miles) wide, and sports a rim 100 meters (330 feet) high. In this simulated-true-color image, the arid landscape appears in varying shades of brick red, brown, and tan. The crater's outline is unmistakable, yet it doesn't necessarily look like a crater; the light and shadows make it look more as if someone pressed a giant cookie cutter into the rock. In this image, the sunlight shines from the southeast (lower right), and the bright arc along the northwestern part of the crater is where the crater walls slope up to the rim. Around the perimeter, the relatively steep walls cast dark shadows. Although it resides in ancient rock, Tenoumer is geologically young, ranging in age between roughly 10,000 and 30,000 years old.
