Board Thread:General Discussion/@comment-27391307-20160529141427/@comment-27391307-20160601214108

It is thought that the Moon was formed when a proto-planet about the size of Mars collided with the early Earth around 4.5bn years ago. The debris left over from impact coalesced to form the Moon. Computer simulations of such an impact are consistent with the Earth Moon system we see in the 21st Century. The simulations also imply that at the time of its formation, the Moon sat much closer to the Earth - a mere 22,500km (14,000 miles) away, compared with the quarter of a million miles (402,336 km) between the Earth and the Moon today The Moon continues to spin away from the Earth, at the rate of 3.78cm (1.48in) per year, at about the same speed at which our fingernails grow.