There were three theories about formation of Earth'[s moon.

Moon formed along with planets in solar system Moon was captured later as it passed bye A mars sized object hit earth about 4.6 billion years back.Outer layers were thrown out..THe debris orbited and formed Moon. The great impact theory. The giant inpact theory is now considered to be ore correct after samples were brought from Moon missions. Picrture credit nhn.ove.edu. ,.