It is called the dark side of the moon because it never faces the earth, this is caused by the fact that the moon's rotation is the same number of days as it's revolution around the earth. Even though it is called the dark side of the moon it still is as bright as the front side. __________________________ There is no "dark side of the Moon"; the entire Moon has a day-night cycle of 29 days. The Moon always has the "Man in the Moon" face turned toward the Earth, and the other, hidden side is the "far side of the Moon".