Far side of the Moon, photographed by Apollo 16

The far side of the moon is not my typo of the album Dark Side of the Moon by Pink Floyd. (That album concept was originally called Dark Side of the Moon: A Piece for Assorted Lunatics and is widely considered one of the greatest rock albums of all time.)

I’m not sure that most people know that our Moon is “tidally locked” in its orbit around the Earth. Tidal forces from Earth have actually slowed down the moon’s rotation so that the same side is always facing the Earth.That means that its rotational and orbital periods are exactly synchronized. And that means that we always see the same view of the Moon no matter when or where you are on Earth.

The far side was first photographed by the Soviet Luna 3 probe in 1959, and was first directly observed by human eyes when the Apollo 8 mission orbited the Moon in 1968. The far side has been suggested as a potential location for a large radio telescope, as it would be shielded from possible radio interference from Earth. To date, there has been no ground exploration of the far side of the Moon.

Here is the far side of the Moon, photographed by one of NASA’s Gravity Recovery and Interior Laboratory (GRAIL) spacecraft.  The video starts with the Moon’s north pole and moves toward the heavily cratered south.

The video is from January 19 and was recorded by the “MoonKAM” aboard one of a pair of GRAIL spacecraft. They went into orbit around the moon this past New Year’s Eve and New Year’s Day.

GRAIL’s mission is to study the Moon’s interior structure and its thermal evolution. But an interesting note I found is that the “KAM” in “MoonKAM” stands for Knowledge Acquired by Middle school students. It was a program that was designed to get grade 5-8 students involved in selecting target areas on the lunar surface to photograph and study. If you’re a teacher, you might want to get you class involved – see https://moonkam.ucsd.edu/home.

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