Classical origin theories

Classical origin theories

. According to the fission theory (left), the rotational speed of the young Earth was great enough for its equatorial bulge to separate from the Earth and become the Moon. In the capture theory (middle), a vagabond moon-sized object once passed close enough to be captured by the Earth's gravitational embrace. We have pictured disruptive capture, with subsequent accretion, but the Moon might have been captured intact. The accretion theory (right) assets that the Moon formed from a disk near the Earth.

Copyright 2010, Professor Kenneth R. Lang, Tufts University