Asteroid 2024 PT5, which almost became a temporary moon to Earth but never officially joined our orbit, is very likely a piece of the actual moon, according to a study published in The Astrophysical Journal Letters. The rock was probably "flung into space by an impact on the lunar surface that occurred sometime within the past tens of thousand years," said The New York Times.
Researchers deduced the object's true nature by observing its movement through space, ruling out that it was human-made space debris. They "studied how the sunlight reflected off the small rock" and found it "didn't match that of any known asteroid type," said USA Today. Instead, the "reflected light more closely matched rocks from the moon."
Lunar missions have "provided precious samples for laboratory study, but space rocks chipped off the moon could add another dimension to our understanding," said Earth.com. Moon-sourced asteroids may allow researchers to study samples from deeper in the moon, which are otherwise difficult to extract. "If a lunar asteroid can be directly linked to a specific impact crater on the moon, studying it could lend insights into cratering processes on the pockmarked lunar surface," said NASA.
"Mini-moon" is a misnomer for 2024 PT5 because it never truly became a second moon to the Earth. However, the asteroid is only the second one discovered to have lunar origins. Now, scientists predict there may be many more. "As telescopes become more sensitive to smaller asteroids," said NASA, "more potential moon boulders will be discovered." | 
