Originally proposed by George Darwin, (son of Charles Darwin), this theory suggested that a rapidly spinning molten earth, due to solar tides and its own vibrations, becomes elongated, than dumbbell-shaped. Eventually, the neck of the dumbbell breaks and the smaller part moved away and stayed in orbit to the larger piece. 

W.H. Pickering took it further by marrying to the theory of continental drift. He suggested that a thin crust had formed before the split took place. The fission would leave behind a large scar and the force of it could crack the remaining crust in many places. Pickering believes this led to the formation of the continental plates. North America seems to fit well in a jigsaw fashion with Western Europe, as does South America with the West coast of Africa.



Fig 1: The jigsaw fit of continents between the Americas and Europe-Africa


This leaves a large, roughly circular scar in the Pacific Basin, which he took to be the scar left behind when the Moon broke free from the Earth.


Fig 2: The circular scar left behind after the Moon broke free


There are two fatal flaws in this model. Firstly the Pacific Basin is far too shallow to be the purported scar. Taking the Earth to be the size of a tennis ball, the Pacific would only be as thick as a postage stamp while the moon is the size of a ping-pong ball! Secondly, physicists have found that the angular momentum and energy involved would give us an Earth and a Moon that should still be spinning four times faster than they do. Differences in the rock composition of both bodies are also not explained