There may be more moon-born asteroids near Earth than we think
ESA/P.Caryl
The giant rock orbiting near Earth appears to have originated from the moon, and is only the second such object known to exist, with perhaps a dozen more awaiting discovery.
The asteroid, called 2024 PT5, is about 10 meters wide. It was discovered in August, but was later captured by Earth’s gravitational pull. become the second moon Between September and November, our planet’s so-called mini-moon.
When we re-examine the asteroid, Teddy Kaleta Researchers at the Lowell Observatory in Arizona found that its appearance does not match that of any other known asteroid. But when we looked at the light reflected from the asteroid to estimate its composition (rich in pyroxene but low in olivine), we found it matched samples from the moon collected by the Apollo 14 mission in 1971. It became clear.
“Apollo 14 primarily sampled the lunar highlands, which are the bright parts of the moon visible from Earth,” Kaleta said. This suggests that something struck the region in relatively recent history, perhaps within the past 200,000 years, blowing rocks containing 2024 PT5 into space, he said. Masu. “So if I had to bet on which part of the moon this object came from, it would probably come from the highlands.”
This makes 2024 PT5 the second asteroid confirmed to be of lunar origin, following the discovery in 2021 that an object called Kamoorewa was also of lunar origin. Both objects are known as quasi-satellites because they share similar orbits. The earth also turns red when exposed to the sun. “It’s like a rock getting a sunburn,” Kaleta said.
The existence of a second satellite asteroid is “very interesting,” Kaleta said. “That means there are a lot of these things in the world. Nature doesn’t just create two things.” Based on the power, we predict that there are about 16 lunar asteroids orbiting close to Earth.
Renu Malhotra Researchers at the University of Arizona, part of the team that deduced the origin of Kamoorewa’s moon, say the lunar asteroid likely remained visible near Earth for millions of years before its orbit “spread out into the larger universe.” It states that it is only visible. They then disappear among the thousands of other asteroids closer to Earth. “It would be very difficult to know where they came from,” she says. Because they are very small and faint.
Such lunar asteroids are not likely to be seen very often because they require the right conditions to form. If the energy of the impact on the moon is too low, the resulting debris will simply fall onto the lunar surface. Too much energy throws the debris into the wider solar system.
“The preferred location is the posterior hemisphere,” Malhotra says. Half of the moon would be facing backwards in its orbit, slowing down the debris and preventing it from leaving the Earth-Moon system.
China plans to launch a mission to visit Kamoo-Arewa, called Tianwen-2, in 2025, which could provide insights into these objects. “These are probably the youngest and most pristine asteroids that have been formed recently,” Malhotra said. “They may contain traces of a shocking history.”
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