A new study suggests that Earth’s “quasi-moon” likely exploded from the actual moon very recently in the solar system’s history.
Kamo’oalewa is a 131 to 328 feet wide (40 to 100 meters) near-Earth object (NEO) released by an asteroid impact 1 million to 10 million years ago, which created 13.7 of the Moon’s -The mile-wide (22 kilometers) Giordano Bruno crater, according to the study.
Kamo’oalewa, or officially designated “469219 Kamo’oalewa”, was discovered in 2016 by the Pan-STARRS 1 asteroid survey telescope in Haleakala, Hawaii, as part of NASA’s Planetary Defense part of an effort to discover space rocks that could hit Earth.
Kamo’oalewa means “oscillating celestial body” in Hawaiian, It was later discovered that it orbited the sun synchronously with the Earth and was spinning extremely fast for an asteroid. These puzzling features have prompted scientists to investigate the origin of quasi-moons. In 2021, research revealed that Kamaualeva’s composition is similar to rocks recovered from the moon, suggesting a lunar origin. The question is, where on the moon did it come from?
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Patrick Michel, a team member and senior researcher at the National Center for Scientific Research, said: “Our main finding is that Kamovaeleva originated from the moon and not from the asteroid belt, contrary to most asteroids that belong to the near-Earth object group.
“Like detectives, we used all the known information about Camo’Aleva and the lunar surface to derive a scenario of the object’s origin, starting with the impact that created the Giordano Bruno crater,” Michel said.
Recreating a ‘cosmic crime scene’ on the moon
Like crime scene investigators, the team connected Kamaualeva to the Giordano Bruno crater. They used computer models to simulate the types of impacts that would create space rocks like a quasi-moon.
This means taking into account factors such as the size and velocity distribution of the ejecta produced and its dynamic evolution. This reconstruction suggests that some of the ejecta ended up in a 1:1 orbital resonance with Earth, with the same dynamics as Kamo’oalewa.
“Our results tell us that Kamo’Aleva is likely a fragment of the lunar surface, and if our hypothesis is correct, we have a direct link to a known impact crater,” Michel said.
“Usually, the best we can do is identify the NEO’s source region in the asteroid belt and understand its current orbit. In such estimates, the region is usually very wide, such as the inner or outer asteroid belt,” he said Add to. “Here we identified a very specific body and location of this object, which is very exciting.”
Michel explained that Kamo’Aleva’s orbit is unstable, so the team linked it to a less ancient crater, perhaps between one and 10 million years old.
“Then we also need the crater to be small enough to produce complete fragments the size of Kamoaelewa,” he continued. “The best candidate at the time was Giordano Bruno, which met both constraints.”
The team’s impact model also gave them an idea of the size of the space bomb, which could create a nearly 14-mile-wide lunar crater and its quasi-lunar ejecta. They estimated that the asteroid that struck the moon would have had to be about 1 mile (1.6 kilometers) wide to create the Giordano Bruno crater and free Kamaualeva.
If an asteroid of this size hit Earth, it would release about the same amount of energy as exploding a one-megaton bomb.
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The findings also have implications for our understanding of the population of near-Earth objects surrounding Earth, suggesting that a greater proportion of these objects than thought may have been created by impacts on the moon or other solar system objects.
“While most NEOs come from the main asteroid belt between Mars and Jupiter, a small number may come from the Moon or elsewhere,” Michel said. “When something unusual happens and when a lunar origin seems possible, we now know we can check whether debris from the moon can be guided into the orbit of the object in question and possibly identify the crater it came from, thus closing the loop “.
Michel added that the discovery of a possible connection between the Giordano Bruno crater and the near-Earth object Kamaualeva is a stark reminder that even during a later, calmer period in the solar system’s 4.6 billion-year history , the impact of a huge space rock will also occur.
This emphasizes the importance of planetary defense programs, such as NASA’s recent Double Asteroid Redirect Test (DART), which studied the effectiveness of changing the direction of an asteroid during a collision with Earth.
Michel said: “The impact occurred in the inner solar system, and although the traces were erased on Earth, they were not erased on the moon. Therefore, our natural satellite contains the impact history of the Earth’s environment over the past 4 billion years. “That’s why some of us are highly involved in planetary defense, NASA’s DART mission, which performed the first asteroid deflection test, and the European Space Agency’s Hera mission, of which I am principal investigator, which will measure DART impact results in detail. ”
Michel acknowledged that the team’s results were only temporary. So while they provide a strong connection between Kamo’Aleva and the moon, further investigation of the asteroid is needed to confirm this connection.
He said: “The next most exciting study of Kamo’Aleva will be provided by China’s Tiawen-2 mission, which will launch in 2025 to sample the asteroid’s surface and return the samples to Earth Performed laboratory analysis. “This is a very challenging task because no one has ever visited such a small object before, and it only rotates once in 28 minutes.
“What sample analysis will tell us for the first time [are] The physical and thermodynamic state of a fragment of this size extracted from the lunar surface by an impact is something we cannot determine in impact models.
The team’s findings were published on Friday (April 19) in the journal Nature Astronomy.
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