A Supercomputer Simulations Gives us a New Look at The Formation of the Moon

Researchers from Durham University’s Institute for Computational Cosmology used the most precise supercomputer simulations ever, revealing an alternative for how the Moon formed 4.5 billion years ago. It showed that a colossal impact between Earth and a Mars-sized body could place a Moon-like body into Earth’s orbit.

Next level simulations

In their hunt for circumstances to help understand the present-day Earth-Moon system, the scientists simulated numerous different impacts at high resolution, altering the angle and speed of the collision along with the masses and rotations of both colliding bodies. These calculations, executed using the SWIFT open-source simulation code, run on the DiRAC Memory Intensive service (“COSMA”), hosted by Durham University on behalf of the DiRAC High-Performance Computing facility.

The additional computational power showed that lower-resolution simulations could lack important elements of large-scale collisions. With high-resolution simulations, scientists can find features that weren’t available in previous studies. Just the high-resolution simulations generated the Moon-like satellite, and the additional information showed how its external layers contained more material originating from the Earth.

Suppose much of the Moon developed directly after the collision. In that case, this might indicate that less became molten throughout development than in the typical concepts where the Moon developed within a debris disk around Earth. These concepts ought to predict different internal structures of the Moon.

Study co-author, Vincent Eke, stated: “This formation route could help explain the similarity in isotopic composition between the lunar rocks returned by the Apollo astronauts and Earth’s mantle. There may also be observable consequences for the thickness of the lunar crust, which would allow us to pin down further the type of collision that took place.”

Additionally, they found that even when a satellite passes so near the Earth that it is expected to get torn apart by the “tidal forces” from Earth’s gravity, the satellite can survive. In reality, it can be driven onto a wider orbit, secure from future destruction.

New possibilities

Jacob Kegerreis, the lead scientist of the study, stated: “This opens up a whole new range of possible starting places for the Moon’s evolution. We went into this project not knowing exactly what the outcomes of these very high-resolution simulations would be. So, on top of the big eye-opener that standard resolutions can give you wrong answers, it was extra exciting that the new results could include a tantalizingly Moon-like satellite in orbit.”

We understand that the Moon developed after a collision between the young Earth and a Mars-sized object called Theia 4.5 billion years ago. Many theories describe the formation of the Moon as a progressive build-up of the particles from this impact. However, this has been challenged by measurements of lunar rocks revealing their composition resembles that of Earth’s mantle, while the impact creates particles that mainly originate from Theia.

This immediate-satellite scenario opens brand-new possibilities for the initial lunar orbit along with the Moon’s predicted makeup and inner framework. This might aid in explaining mysteries like the Moon’s slanted orbit away from Earth’s equator; or generate an early Moon that is not completely molten, which some researchers suggest could be a better match for its thin crust.

The many upcoming lunar missions ought to reveal new hints regarding what kind of colossal impact resulted in the Moon, which consequently will tell us more about Earth’s history.

The researchers consisted of scientists at NASA Ames Research Centre and the University of Glasgow, UK, and their simulation findings have been published in the Astrophysical Journal Letters.

Originally published by: ScitechDaily

Reference: “Immediate Origin of the Moon as a Post-impact Satellite” by J. A. Kegerreis, S. Ruiz-Bonilla, V. R. Eke, R. J. Massey, T. D. Sandnes and L. F. A. Teodoro, 4 October 2022, Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ac8d96