This image shows a typical asteroid. Most asteroids come from the main asteroid belt between Mars and Jupiter, but some are fragments that broke off from the moon's surface after impacts. CNN
A small space rock that lingered near Earth last year, initially referred to as a "mini-moon," might actually be a fragment of the moon itself. The object, designated as 2024 PT5, was about 33 feet (10 meters) wide, and although it was close enough to Earth to spark excitement, it poses no threat of collision with our planet. The object’s trajectory ensures it won’t come anywhere near Earth in the coming decades.
2024 PT5 was discovered on August 7, 2024, by the South Africa-based observatory of the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS). Despite early predictions that the space rock might orbit Earth as a mini-moon, it maintained a horseshoe-shaped orbit around the sun that never fully allowed it to settle into Earth's orbit. After its brief close approach, the object has since been slowly moving away into a more distant path.
What makes 2024 PT5 truly interesting is its orbit around the sun, which is surprisingly similar to Earth’s. This suggests that the object could have originated from our corner of the solar system. Dr. Teddy Kareta, a postdoctoral associate at Lowell Observatory in Arizona and lead author of a study on 2024 PT5, pointed out that the object never actually entered into orbit but came very close. It followed a rare trajectory known as a “horseshoe orbit” and remained in this path for about two months before receding back.
Kareta's team used the Lowell Discovery Telescope and the NASA Infrared Telescope Facility at Mauna Kea Observatory in Hawaii to study the object. As sunlight reflected off the surface of 2024 PT5, the scientists noticed something striking. The surface of the object appeared similar to rocks retrieved from the moon, particularly in its composition of silicate minerals. These minerals are found on the moon, not on typical asteroids, which led Kareta to believe that 2024 PT5 could indeed be a piece of the lunar surface, ejected during an ancient impact event.
This discovery adds to a growing body of research into lunar asteroids—small space rocks that were once part of the moon and were sent flying into space after asteroid or comet impacts. Kareta’s team ruled out the possibility that 2024 PT5 was space debris, such as an old rocket, by carefully analyzing how the object moved in space. Space debris reacts differently to solar radiation pressure than natural asteroids, and 2024 PT5’s movement indicated that it was indeed a dense rock, not man-made debris.
The theory that 2024 PT5 is a fragment of the moon is supported by experts like Robert Jedicke, a solar system specialist at the University of Hawaii’s Institute for Astronomy. Jedicke agreed with the study’s findings, noting that it’s plausible some objects ejected from the moon due to impacts could eventually end up in Earth-like orbits, like that of 2024 PT5.
While 2024 PT5 is only the second object discovered with such an orbit—following 2016’s asteroid 469219 Kamo’oalewa—researchers are excited by the possibilities. As technology improves and more sensitive telescopes come online, scientists expect to discover more objects like 2024 PT5 and gain insight into how many fragments of the moon are floating around in space.
In total, researchers estimate that up to 16 lunar-origin asteroids have already been found, and more are expected as technology advances. As the study of these objects continues, scientists aim to learn more about the moon’s history, impacts, and the wayward rocks it has ejected into space.
