Credit: Dr. Jacob Kegerreis
Scientists at Durham University’s Institute for Computational Cosmology used the most detailed supercomputer simulations to date to reveal an alternative explanation for the moon’s origin, with a giant impact that instantly sent a lunar-like body into orbit around Earth.
The researchers simulated hundreds of different impacts ranging from the angle and speed of the collision, as well as the masses and spins of the two colliding bodies in their search for scenarios that could explain the current Earth-moon system. These calculations were performed 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 computing power revealed that lower-resolution simulations may miss important aspects of large-scale collisions, allowing researchers to discover features inaccessible to previous studies. Only the high-resolution simulations produced the moon-like satellite, and the extra detail showed how the outer layers were richer in material sourced from Earth.
If much of the moon formed immediately after the giant impact, it could also mean that less melted during its formation than in the standard theories where the moon grew in a disk of debris around the Earth. Depending on the details of the subsequent solidification, these theories should predict different internal structures for the moon.
Credit: Dr. Jacob Kegerreis
Co-author of the study, Vincent Eke, said: “This formation route could help explain the similarity in isotopic composition between the lunar rocks returned by the Apollo astronauts and the Earth’s mantle. There may also be observable implications for thickness. of the lunar crust, which would allow us to further determine the type of collision that occurred.”
In addition, they found that even when a satellite passes so close to Earth that you would expect it to be torn apart by the “tidal forces” of Earth’s gravity, the satellite can not only survive, but also be put into a wider orbit. pushed, safe from future destruction.
The study’s lead researcher, Jacob Kegerreis, said: “This opens up a whole new range of possible starting places for the evolution of the moon. We went into this project not knowing exactly what the results of these very high-resolution simulations would be. So “Besides the big eye-opener that standard resolutions can give you wrong answers, what was extra exciting was that the new results could include a tantalizing moon-like satellite in orbit.”
Credit: Dr. Jacob Kegerreis
Credit: Dr. Jacob Kegerreis
The moon is thought to have formed after a collision 4.5 billion years ago between the young Earth and a Mars-sized object called Theia. Most theories create the moon by gradual accumulation of the debris from this impact. However, this has been tested by measurements of moon rocks showing that their composition is similar to that of the Earth’s mantle, while the impact produces debris mainly from Theia.
This direct satellite scenario opens up new possibilities for the initial orbit of the Moon, as well as the predicted composition and internal structure of the Moon. The many moon missions to come should reveal new clues as to what kind of giant impact led to the moon, which in turn will tell us about the history of Earth itself.
Credit: Dr. Jacob Kegerreis
Credit: Dr. Jacob Kegerreis
The research team included scientists from NASA Ames Research Center and the University of Glasgow, UK, and their simulation results have been published in the Astrophysical Journal Letters.
Supercomputer simulations can unravel the mystery of the moon’s formation
JA Kegerreis et al, Immediate origin of the moon as a post-impact satellite, Astrophysical Journal Letters (2022). www.hou.usra.edu/meetings/lpsc2022/pdf/1724.pdf
Quote: Giant impact could have formed moon faster, scientists reveal in new simulations (2022, Oct. 4), retrieved Oct. 4, 2022 from https://phys.org/news/2022-10-giant-impact-moon-rapidly- scientists .html
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