Earth has its fair share of fleeting companions. But sometimes, these so-called “mini-moons” have a surprising origin story. Take 2024 PT5, a bus-sized asteroid that drifted near Earth last year. Recent research reveals this might not have been just another run-of-the-mill asteroid—it might be a chunk of the Moon, blasted into space thousands of years ago.
The asteroid passed safely at 1.1 million miles (roughly five times the Moon’s distance) and has a fascinating backstory. Using the Lowell Discovery Telescope in Arizona and NASA’s Infrared Telescope Facility in Hawaii, scientists analyzed 2024 PT5’s surface and discovered that the mini-moon reflects light almost identically to lunar rocks.
Particularly, it reflects light identically to those lunar rocks brought back during NASA’s Apollo 14 mission. This evidence, they write in a new paper, seems to point toward the mini-moon originating from the Moon’s highlands after a massive impact tore it loose.
Astronomer Teddy Kareta, who led the new study, called the discovery “a story about the Moon as told by asteroid scientists.” The asteroid’s silicate-rich makeup is very common in lunar rocks but rare in traditional asteroids. This discovery seems to have sealed the case for its lunar origins.
The researchers also say they ruled out any artificial origin, confirming that this mini-moon is all-natural and likely originated with our Moon. This isn’t the first time a near-Earth asteroid has been linked to the Moon. 2024 PT5 is the second confirmed lunar fragment after 469219 Kamo’oalewa, an asteroid traced to a crater on the Moon’s far side.
Scientists now believe there may be a larger population of mini-moons of lunar origin waiting to be discovered—at least 16 candidates have already been identified. Studying lunar fragments like 2024 PT5 can deepen our understanding of near-Earth objects and their origins.
It also has practical implications: cataloging these mini-moons could improve planetary defense models, helping scientists assess the risks posed by objects that might one day cross our path. With this information, they can hopefully create more programs like NASA’s D.A.R.T., which redirected an asteroid’s path when it collided with it.
