This evening club member Mark Christensen will discuss theories concerning the formation of the Moon, its post-formation history, and the future of the Earth-Moon system. This is a tale more complex and exciting than the casual reader might think. The Earth-Moon system is unique in our solar system in that it consists of a rocky planet and a single satellite that is 1/4 the diameter of its primary. The leading theory, based on, among other things, the chemistry of rocks on both the Earth and the Moon, is that the Moon formed when the Earth was struck by another planetary body. However, there is as yet no direct evidence that definitively proves this theory, with which there are dynamical problems as well. After this evening you may never look at the Moon again in the same way!