A giant impact may have quickly thrown the moon into orbit around Earth instead of creating a disk of debris from which the moon gradually formed over time, new research suggests.
A highly detailed computer simulation created by Durham University’s Institute for Computational Cosmology revealed this alternate origin story for Earth’s lunar companion. This new, aptly named “immediate satellite scenario” would mean that the proto-moon was less molten during its formation and would suggest that much of the moon formed immediately after a giant impact on Earth.
This theory of faster formation 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 was the moon formed?
the Moon It is believed to have formed about 4.5 billion years ago when the Earth was hit by an object from space about the size of Mars which scientists have named ‘Theia’. It was previously theorized that this impact ejected a debris field from which the moon gradually formed. One consequence of this would have been that the moon was created primarily from material provided by Theia rather than material from Earth. This idea was challenged when it was discovered that Moon rocks seem to have a composition which is very similar to the mantle of Land.
The high resolution results obtained with the impressive computing power of the DiRAC Memory Intensive service called COSMA (opens in a new tab) located at Durham University 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 Vincent Eke, co-author of the research and a physicist at Durham University. said in a statement (opens in a new tab). “There may also be observable consequences for the thickness of the lunar crust, which would allow us to further pinpoint the type of collision that took place.”
The team’s simulation took into account hundreds of different impact scenarios that varied the angle and speed of Theia’s collision, as well as varying the masses and spins of the two colliding bodies. It also showed that a large natural satellite like the still-forming moon could survive in a close orbit around Earth.
It was previously thought that a rapidly forming large body near Earth would be torn apart by tidal forces emerging from our planet. gravitational influencethus favoring a slow process of creation of the moon.
These new simulations suggest that such a body could not only survive tidal forces, but could be pushed into a higher orbit, freeing it from the threat of future destruction by such forces.
“We started 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 wrong answers, it was very exciting that the new results could include a tantalizing satellite similar to the moon in orbit,” 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 evolution of the moon.”
The team’s investigation was published on October 4 (opens in a new tab) in astrophysical journal letters.
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