Earth Is Temporarily Getting a Second ‘Moon’

Starting next week, the moon, Earth’s closest celestial body, will be joined by a new neighbor: a second moon.

From Sept. 29 until Nov. 25, astronomers calculate that 2024 PT5— which is what scientists think is an asteroid but have dubbed a “mini-moon”—will be looping around Earth. It will eventually break free of the planet’s gravitational orbit.

Sadly, at just about 10 meters, the mini-moon will be extremely hard to see from Earth, but its presence will be there nonetheless for almost two months. The asteroid, which was discovered on Aug. 7 by NASA, originated from the Arjuna asteroid belt, where it will likely return once it leaves Earth’s orbit.

“Earth can regularly capture asteroids from the Near-Earth object (NEO) population and pull them into orbit, making them mini-moons,” researchers Carlos de la Fuente Marcos and Raúl de la Fuente Marcos wrote in their published research. 

According to NASA, a Near-Earth Object is any body, asteroid or otherwise, that is “nudged” by the gravitational attraction of nearby planets that pushes them to Earth’s neighborhood. NASA has their own program that works to track the locations and orbits of tens of thousands 28,000 asteroids, with data pages for every NEO, including their orbital parameters and a close approach summaries.

Paul Chodas, director of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory, said 2024 PT5 is possibly a piece of ejecta from an impact on the moon, meaning the mini-moon may have originated as a piece of the original moon, according to the New York Times.

Mini-moons can come in multiple types, according to research. The first, “temporary captured orbiters,” are long episodes in which bodies perform one or more revolutions around the Earth and can remain in the planet's orbit for many months, or even years. The second, which includes the upcoming mini-moon, are dubbed “temporary captured flybys,” as they do not complete one revolution and remain in Earth’s orbit for a very short period of time.