A giant impact may have quickly put the moon into orbit around Earth rather than creating a disk of debris from which the moon gradually formed over time, according to new research.
A very detailed computer simulation created by Durham University’s Institute of Computational Cosmology has revealed this alternate origin story for Earth’s lunar companion. This aptly named new “immediate satellite scenario” would mean that the proto-moon melted less during its formation and suggests that much of the moon formed immediately after a giant impact on Earth.
This faster-forming theory would also suggest a different internal composition for the moon that could offer an explanation for some of the curious Earth-like features seen in lunar samples.
Related: How did the moon form?
The moon It is thought to have formed around 4.5 billion years ago when the Earth was hit by an object from space about the size of March which scientists called ‘Theia.’ It was previously theorized that this impact threw up a debris field from which the moon gradually formed. A consequence of this would have been that the moon was primarily created by material provided by Theia as opposed to material from Earth. This idea was challenged when it was discovered that moon rocks seem to have a composition which looks a lot like the coat of Earth.
The high-resolution results obtained with the impressive computing power of the DiRAC Memory Intensive service called cosmos (opens in a new tab) located at the University of Durham in England showed an outer layer of the moon rich in material from Earth.
“This formation pathway could help explain the similarity in isotopic composition between moon rocks returned by Apollo astronauts and Earth’s mantle,” said research co-author and physicist Vincent Eke from the University of Durham. said in a press release (opens in a new tab). “There may also be observable consequences for the thickness of the lunar crust, which would allow us to better understand the type of collision that took place.”
The team’s simulation considered hundreds of different impact scenarios that varied the angle and speed of Theia’s collision in addition to varying the masses and rotations of the two colliding bodies. It also showed that a large natural satellite like the still-forming moon could survive in close orbit around the Earth.
It was previously thought that a large rapidly forming body near Earth would be torn apart by tidal forces emerging from the surface of our planet. gravitational influencethus promoting a slow process of creation of the moon.
These new simulations suggest that such a body could not only survive tidal forces, but could actually be pushed into a higher orbit, freeing it from the threat of future destruction by such forces.
“We went into this project not knowing exactly what the results of these very high resolution simulations would be. So, in addition to the big reveal that standard resolutions can give you the wrong answers, it was very exciting that the new results could include an orbiting moon-like satellite,” co-author and NASA Ames scientist Jacob Kegerreis said in the team’s statement. “This opens up a whole new range of possible starting points for the moon’s evolution.”
The team’s research was published on October 4 (opens in a new tab) in the letters of the Astrophysical Journal.
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