Here's something you don't see every night: the far side of the Moon, photographed by one of NASA's Gravity Recovery and Interior Laboratory (GRAIL) spacecraft.
The Moon is "tidally locked" in its orbit around the Earth, meaning its rotational and orbital periods are exactly synchronized. As a result, we always see the same view of the Moon no matter when or where (on Earth) we look at it. In this interesting video, released last week by NASA, we get a rare glimpse of the Moon's other side, starting with the north pole and moving toward the heavily cratered south.
The video was captured on January 19 by the "MoonKAM" aboard one of a pair of GRAIL spacecraft that were launched last Fall and began orbiting the Moon on New Year's Eve and New Year's Day. The primary mission of GRAIL is to study the Moon's interior structure and to learn more about its thermal evolution.
GRAIL is also the first planetary mission by NASA to carry instruments dedicated solely to education and public outreach. The "KAM" in "MoonKAM" stands for Knowledge Acquired by Middle school students. The program, led by former astronaut Sally Ride, will engage fifth- to eighth-graders from across the country in selecting target areas on the lunar surface to photograph and study. Educators interested in participating can register at the MoonKAM website. To learn more about the video and GRAIL, see the NASA news release.