The most likely theories state that the Earth’s moon was created by a collision of the Earth with another planet. The other planet was about the size of Mars and hit the Earth in a grazing collision. Some of the material that was thrown up fell back to the Earth. Other material got into Orbit around the Earth and created the moon. It is also possible that the left-over material from this collision formed the asteroid belt. This expanse of rubble is located between the paths of Mars and Jupiter. The planet that collided with the Earth destroyed itself by doing so. Studies of rocks from the moon have especially supported this theory. If it’s true then the moon should be made out of material from two planets. There must also be a lot of material from the other planet on the moon.
A slightly modified simulation in closer view and higher Resolution
(half particle size = 8-fold number of particles = 64-fold calculation time)
The movies show double collisions. What exactly happens in a collision strongly depends on the flight path parameters