How was the Moon formed?
There are various theories on the evolution of Earth and Moon system. Currently four main hypotheses have been considered to explain the origin of the Moon: 1. Simultaneous Formation: Earth and the Moon were formed from the solar nebula near each other. This theory is able to explain why the Earth and the Moon rocks are isotopically so similar, but cannot explain why the Moon is depleted in Iron (Fe). 2. Capture: Moon formed somewhere else in the Solar System where the iron content was lower. After it formed, it drifted close to the Earth and was captured by the Earths gravitational field. This theory cannot explain why the Earth and the Moon rocks are isotopically similar but explains the high angular momentum of the Earth-Moon system. 3. Fission: According to this hypothesis, the Moon broke off from the hot molten Earth while the Earth was spinning very rapidly. This hypothesis can explain why the Earth and the Moon rocks are similar, chemically and isotopically, and the low iron con
