How was the Moon formed?

Various possibilities have been put forward thru the years

THe following information was known before Apollo

We now know these pieces of information about the Moon.

In 1975, Will Hartmann and Donald Davis proposed the theory that the Moon formed as the result of a major collision.

Giant Impact

  1. A planetary embryo strikes the Earth.
  2. Its core accretes onto the Earth's core.
  3. Its mantle is fragmented and vaporized (along with a lot of the outer surface of the Earth).
  4. Some returns to Earth, but the rest clumps together gravitationally.

The nagle of impact is very important here - by no means every impact will produce the required outcome.

This is likely to have been the last giant impact suffered by the Moon, because any further impacts would have destroyed the Moon.

A central tenent of lunar formation appears to be the magma ocean suurounding the new-born Moon. Observations from Clementine in 1994 confirmed this part of the theory. Initially the entire Moon may possibly have been molten.