How does the moon, based on it's size and weight, orbit the Earth when the Earth has relatively weak gravity?

I don’t know if what I am asking is relative or ignorant, but I am curious to know based on what scientists said in Houston: “the Moon rang like a bell”.

One theory claims that the Moon was a part of Earth and it was chunked off from a collision.

Another theory claims that the Moon is hollow.

Another theory is that the Moon is an extraterrestrial craft.

Finally, there is a theory that the Moon isn’t real at all.

Has anyone heard or read about this? I’m not a David Ecke fan, but a point was brought up on his behalf that I have not confirmed because I am not savvy on the lines of physics.