According to Israeli researchers, the moon was formed when Earth’s former moons collided. Their theory has been published in the journal Nature Geoscience.

“Our model suggests that the ancient Earth once hosted a series of moons, each one formed from a different collision with the proto-Earth,” adds study co-author Hagai Perets, of the Technion, and Weizmann Institute. “It’s likely that such moonlets were later ejected, or collided with Earth or with each other to form bigger moons.”

The research team created 800 simulations of impacts with Earth. Consequently, the team determined that their new model is consistent with the understanding of how the planet formed.

“We believe Earth had many previous moons,” stated Perets, who added that, “a previously formed moon could therefore already exist when another moon-forming giant impact occurs.” The scientists speculate that the moons’ gravitational attraction caused them to cross each other’s orbits, collide and then merge eventually. Over time, such moon on moon collisions resulted to the bigger moon that we know of today.

Previously, scientists believed that the moon was formed by a giant collision with the ancient Earth and another planet, which had the size of Mars.Researchers from the University of California, Davis, SETI Institute in Mountain View, California, University of Maryland and Harvard University also developed a new model that also tried to explain how the moon was formed. According to them, the moon and our planet originated from the debris of a giant impact.

This explains why the moon has some Earth-like compositions. The scientists believe that the moon then went into LaPlace plane transition. At this point, Earth was flipped upright but did not experience changes in its orbit.

Subsequently, within tens of millions of years, the moon slowly distanced itself from Earth. It then underwent into Cassini transition, which resulted to its current position now.