
Last year, a small asteroid called 2024 PT5 caught the world’s attention when it was spotted lingering near Earth for several months.
Measuring about 33 feet (10 meters) wide, the asteroid wasn’t a threat to our planet, but its unusual orbit suggested it might have a special connection to Earth.
New research now reveals that 2024 PT5 might actually be a chunk of the moon, blasted into space thousands of years ago after a massive impact.
Astronomer Teddy Kareta from Lowell Observatory in Arizona led the study, which was published in Astrophysical Journal Letters.
His team found that the asteroid’s surface reflects sunlight in a way that matches lunar rock samples.
“We had an idea it might be from the moon, but the real proof came when we saw that its composition is rich in silicate minerals found in lunar rocks,” Kareta explained.
The asteroid also appears relatively young, astronomically speaking. It seems to have been in space for only a few thousand years, as it hasn’t experienced “space weathering,” which would have turned its surface redder over time.
The asteroid was first detected on August 7, 2024, by a telescope in South Africa that is part of the University of Hawai’i’s Asteroid Terrestrial-impact Last Alert System (ATLAS). Kareta’s team followed up with observations using the Lowell Discovery Telescope and NASA’s Infrared Telescope Facility in Hawai’i.
When scientists first saw 2024 PT5, they had to rule out the possibility that it was a piece of space junk, like an old rocket booster. Space debris and natural asteroids move differently in space because of their response to sunlight.
The sun’s light exerts a tiny force called “solar radiation pressure” on objects in space. Lightweight human-made debris, like hollow rocket parts, gets pushed around more easily, like a tin can in the wind. Natural objects like asteroids are much denser and less affected.
NASA’s Center for Near Earth Object Studies (CNEOS) analyzed 2024 PT5’s motion under gravity and sunlight pressure. They found that the asteroid’s movement wasn’t consistent with space junk, confirming it’s a natural object.
“The fact that 2024 PT5 doesn’t move like space debris shows it’s much denser and likely a solid chunk of rock,” said Oscar Fuentes-Muñoz, a NASA postdoctoral researcher and co-author of the study.
2024 PT5 isn’t the first asteroid thought to be a lunar fragment. In 2016, scientists discovered another asteroid, 469219 Kamo’oalewa, with a similar Earth-like orbit around the sun. It, too, is believed to have been ejected from the moon after a large impact.
As telescopes become more advanced, researchers expect to find more small asteroids that could also be pieces of the moon. Studying these objects could teach us more about the moon’s history and cratering processes.
If scientists can match an asteroid to a specific crater on the moon, it might reveal information about the moon’s surface and even its deeper layers. These lunar fragments might one day provide material for future research, giving scientists access to parts of the moon we can’t currently reach.
“This is a story about the moon told by asteroid scientists,” said Kareta. “It’s rare for asteroid studies to lead us into new questions about the moon, but that’s exactly what 2024 PT5 is helping us do.”
This discovery offers exciting possibilities for both asteroid and lunar science, shedding light on the complex relationship between Earth, its moon, and the asteroids that pass nearby.
Source: NASA.