This fall, an asteroid will be captured by Earth’s gravitational pull and become a temporary “mini moon.” It is expected to orbit around the Earth in a horseshoe path from Sept. 29 to Nov. 25 before exiting Earth’s gravitational pull and rejoining the sun’s orbit.
The asteroid, named 2024 PT5, will not be visible to the naked eye as it is incredibly small – only 11m long. For reference, the moon has a diameter of approximately 3,474km.
“You need a large scope and imaging equipment, CCD camera, to even maybe see a fuzzy dot. And then you’d have to take several images and see if one of those little, tiny specks moved against the background stars. But it’s nothing that you’re going to be able to go out and just view,” said Sunriver Nature Center Observatory Manager, Paul Poncy.
2024 PT5 originates from the Arjuna asteroid belt, a secondary asteroid belt made of space rocks that follow orbits very similar to that of Earth at an average distance to the sun of about 93 million miles.
Some asteroids from this region occasionally get trapped by other gravitational fields, such as Earth’s, if they get too close. In this case, 2024 PT5 will join Earth’s gravitational field for a short time before returning to its original path.
This is not the first time Earth has picked up stray asteroids. The 2022 NX1 asteroid became a mini moon in both 1981 and 2022. 2024 PT5 is also expected to return to Earth’s orbit in 2055. It is also possible that many more mini moons have gone unnoticed.
“This story highlights just how busy our solar system is and how much there is out there that we haven’t discovered, because this asteroid was only discovered this year,” astronomer and podcaster Dr. Jennifer Millard told BBC News.
