The most well accepted theory about the Moon formation bases itself in the idea that a planet with roughly the size of Mars crashed into Early Earth about 4.5 billion years ago, leaving behind big chunks of crust that with time bonded and formed the Moon.
Although there’s good evidence to support that idea, scientists from the University of California, Davis, have formed a new hypothesis, which states that both the Earth and the Moon have formed from the same material, and helps to explain why both Earth and the Moon have very similar chemical composition.
This new model suggests that the ‘giant impact’ that occur, was much intense than previously thought, destroying grand part of the Early Earth and the hypothetical planet that smashed into it, Theia. Then, after the planet start cooling down, most of the material has fallen back.
So, a violent planetary smash still occurred, but the Moon isn’t the remnant of something that hit Earth, but instead, is a big piece of the same material that formed Early Earth.
As you can see, the team’s new model show that the Moon’s original position was much higher, and Earth would most likely spin very fast, so we would have had a 2-3 hours-a-day, but tens of millions of years of gravitational forces, have caused this spin to slow down, and a second transition point happened, bringing the Moon to its current 5-degree inclination. So, in other words, the scientists suggest that the Sun helped to shift Earth to its current 23-degree tilt, which made Moon shift to its 5-degree inclination, and they say that this inclination is a big piece on this new hypothesis and they plan to test various parts of their theory in the months to come, more specifically in terms of the chemical composition of the two celestial bodies.
This research was publish in the Nature.