A NASA spacecraft explores the moon's permanent shadows.
The walls within some craters at the moon's poles have gone without sunlight for as long as two billion years. Known as permanently shadowed regions, these craters lie almost perpendicular to the sun, never receiving its warmth or light. By bouncing laser beams off the moon's surface, NASA's Lunar Reconnaissance Orbiter (LRO) mapped the shape and elevation of these incredibly dark areas. Detailed 3-D models constructed from the data, combined with data collected by other instruments aboard the spacecraft, reveal which craters are fully hidden from the sun's rays, and which crater floors are cold enough for chemicals such as water to build up in the lunar soil. Watch the video to learn more.