The details of the formation of the moon remain a mystery until then. Researchers from the University of Durham have developed supercomputer simulations showing how this ancient collision could have happened.
Most astronomers believe that the young Earth was attacked by a Mars-sized object called Theia about 4.5 billion years ago. From the wreckage, the proto-moon emerged. Orbiting the Earth, it cooled down and collected debris from orbit. At the time, the Moon was much closer to Earth than it is today.
Teia’s speed, angle of impact, and body rotation speed influenced the collision with the Earth and the formation of the Moon. The research team examined a wide range of possible conditions, from no spin to fast spin and from gliding to more direct hits in their new study. The data made it possible to simulate the collision of Theia with the Earth and the formation of the Moon.
When simulations tested the impact of the non-rotating Theia, the collision resulted in a satellite with a mass of about 80% of the Moon. And the addition of a small rotation led to the fact that the second moon was in orbit around the Earth. In doing so, some of the collisions studied led to the merger of the early Earth and Theia, while others showed a simple glancing impact between bodies.
Researchers will continue to refine the models by looking at how mass, speed, rotation, and other factors might affect the impact that formed the moon.