Question:What is the most likely origin of the Moon?
The current favourite theory for the origin of the Moon is that the Moon was produced from material blasted upwards from the newly formed proto-Earth by a massive collision with a Mars sized body, which had also been formed in the early solar system.
This is often called the Giant Impact theory.
The collision happened billions of years ago.
Scientists calculate that most of the Moon came from the colliding object rather than the Earth, so the Moon is mostly the remains of this small planet.
In the collision more lighter elements were thrown upwards and more heavier elements remains behind, so the Moon has a lower abundance of the heavier elements than the Earth.