The prisoner said. This hypothesis holds that the moon was originally an asteroid in the solar system. Once, because it traveled near the earth, it was captured by the gravity of the earth and never left the earth again. There is also a view similar to the capture theory, that is, the earth keeps accumulating substances that enter its orbit. As time goes on, more and more things accumulate and finally form the moon. However, it has also been pointed out that the earth may not have that great ability to capture a planet as big as the moon.
Homologous theory This hypothesis holds that both the Earth and the Moon are floating nebulae in the solar system, and they form stars simultaneously through rotation and accretion. In the process of accretion, the earth is a little faster than the moon and becomes a "brother". This assumption is also challenged by objective existence. Through the laboratory analysis of the rock samples brought back from the moon by Apollo 12 spacecraft, it is found that the moon is much older than the earth. Some people think that the moon should be at least 7 billion years old.
Big collision theory. This is a new hypothesis about the origin of the moon. At the symposium on the Moon and Planets held at Johnson Space Center in Houston, Ben Ci and Slattery of Los Alamos National Laboratory and Cameron of Smith Center for Astrophysics of Harvard University put forward the collision hypothesis. This hypothesis holds that in the early stage of the evolution of the solar system, many "star particles" were formed in interstellar space, and asteroids grew up through collision and accretion. Planets and asteroids merged to form the primitive earth, and at the same time formed a celestial body equivalent to 0. 14 times the mass of the earth. During their respective evolution, these two celestial bodies respectively formed a metal core mantle and a shell dominated by iron and silicate. Because the two celestial bodies are not far apart, there is a great possibility of meeting.