A small space rock that briefly approached Earth in 2024 has sparked interest among astronomers, who now believe it may be a fragment of the Moon dislodged thousands of years ago, CNN reports.
The object, known as 2024 PT5, measures approximately 33 feet (10 meters) wide and has a distinctive orbit around the Sun that hints at its lunar origins.
Researchers, led by Dr. Teddy Kareta of the Lowell Observatory in Arizona, published their findings on January 14 in Astrophysical Journal Letters. Their analysis reveals that 2024 PT5 likely came from the Moon due to its mineral composition, which closely resembles lunar rock samples.
Although initially labeled a potential “mini-moon,” 2024 PT5 never actually entered Earth’s orbit. Instead, it followed a rare horseshoe trajectory that brought it near our planet for about two months before it receded into a distant orbit.
“It was never really in orbit,” said Dr. Kareta. “But it approached Earth, had its orbit altered by the Earth-Moon system, and then receded away in a fundamentally rare trajectory.”
The discovery sheds light on a growing population of lunar-origin asteroids, which scientists believe are fragments ejected from the Moon during ancient impact events.
Using the Lowell Discovery Telescope and NASA’s Infrared Telescope Facility in Hawaii, Kareta and his colleagues determined that sunlight reflecting off 2024 PT5’s surface revealed a composition rich in silicate minerals commonly found on the Moon.
“We had a general idea that this asteroid may have come from the Moon, but the smoking gun was its mineral composition — unlike typical asteroids but identical to lunar rock samples,” Kareta explained.
The object also appears relatively young, with scientists estimating that it may have been in space for only a few thousand years.
To confirm that 2024 PT5 was a natural space object rather than human-made debris, such as an old rocket, the team analyzed how the rock moved under solar radiation pressure. Manufactured debris tends to be pushed around by sunlight differently than dense space rocks.
“Space debris is relatively light and gets nudged by solar radiation,” said Oscar Fuentes-Muñoz, a NASA researcher who co-authored the study. “The fact that 2024 PT5 doesn’t move this way shows it’s much denser and is indeed a space rock.”
The idea that asteroids like 2024 PT5 might be fragments of the Moon is gaining traction among researchers. The discovery follows the identification of Kamo’oalewa, another lunar-origin asteroid spotted in 2016.
“This is a growing field,” said Robert Jedicke, a solar system expert at the University of Hawaii’s Institute for Astronomy. “The hypothesis that these objects are chips off the Moon makes perfect sense.”
If confirmed, lunar-origin asteroids could provide valuable insights into the Moon’s surface composition and the frequency of impact events that send debris into near-Earth space.
As astronomers work to identify more lunar fragments, upcoming advanced telescopes, like the Vera Rubin Observatory in Chile and NASA’s NEO Surveyor mission, are expected to enhance detection capabilities.
“We know there’s a whole population of these objects waiting to be discovered,” Kareta noted. “It’s like searching for needles in a haystack, but with better telescopes, we’ll find them.”
