Astronomers have taken a step towards understanding how the Moon could have formed as a result of a gigantic collision between the early Earth and another massive object 4.5 billion years ago.
Scientists, led by Durham University in the UK, simulated supercomputers at the DiRAC High-Performance Computing facility to send a Mars-sized planet called Theia to collide with early Earth.
Their simulations yielded an orbiting body that could potentially transform into a Moon-like object.
While scientists are cautiously saying that this is not conclusive proof of the Moon’s origin, they add that it could be a promising stage in understanding how our closest neighbor might have formed.
The results were published in the journal Monthly Notices from the Royal Astronomical Society.
The Moon is believed to have formed as a result of the collision between the early Earth and Theia, what scientists believe may have been an ancient planet in our solar system, about the size of Mars.
The scientists ran simulations to track material from the early Earth and Theia for four days after they collided, and then performed other simulations after Theia spun like a pool ball.
The simulated collision with early Earth produced different results depending on the size and direction of Tei’s initial rotation.
At one end, the collision brought the two objects together, while at the other end it hit and ran away.
Importantly, a simulation in which no spin was added to Theia produced a self-gravitating lump of material with a mass of about 80% of the Moon, while another Moon-like object was created with the addition of a small amount of spin.
The resulting clump that would settle in orbit around the Earth after the collision would have grown by sweeping a disk of debris surrounding our planet.
The simulated clod also has a small iron core, similar to that of the Moon, with an outer layer of materials formed from early Earth and Theia.
A recent analysis of oxygen isotope ratios in lunar samples collected during Apollo space missions suggests that the Moon may have been formed by a mixture of early Earth and impact material.
Lead author Sergio Ruiz-Bonilla, a PhD student at Durham University’s Institute of Computational Cosmology, said: “By adding varying amounts of spin to Theia in simulations or having no spin at all, it gives a whole range of different results for what could have happened when the early Earth was struck. by a massive object billions of years ago.
“It is exciting that some of our simulations have produced this orbiting lump of material that is relatively little smaller than the Moon, with a disk of additional material around the Earth after the collision that would help the lump grow over time.
“I wouldn’t say it’s the Moon, but it’s certainly a very interesting place to look for.”
The research team led by Durham now plans to conduct further simulations of the mass, speed and spin speed of both the target and the impactor to see what this is having on the formation of a potential moon.
Co-author Dr. Vincent Eke, of Durham University’s Institute of Computational Cosmology, said: “We get a range of different results depending on whether we spin Theia before it collides with early Earth.
“It is especially fascinating that when Theia has no or very little rotation, the collision with the early Earth leaves a trail of debris behind, which in some cases includes a body large enough to merit the proto-Moon.
“There may be many possible collisions that have yet to be investigated that could bring us even closer to understanding how the Moon was formed.”
The research was carried out by the Durham University Institute for Data Science and the School of Physics and Astronomy at the University of Glasgow, UK.
High-resolution simulations were performed using SWIFT open simulation code. They were carried out through the DiRAC Memory Intensive (“COSMA”) service operated by Durham University on behalf of DiRAC High-Performance Computing.
The research was funded by the Science and Technology Facilities Council, part of the UK’s Research and Innovation organization.
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