Earth Is Set to Have Another Moon in Its Orbit—What That Means

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A new moon is expected to be pulled into the Earth’s orbit by the end of September, but the rare phenomenon won’t last long.

The visiting moon is technically an asteroid known as 2024 PT5, and was initially spotted Aug. 7 by NASA’s Asteroid Terrestrial-Impact Last Alert System (ATLAS) initiative, which warns of asteroid impacts. Unlike the existing moon—which has orbited our planet for about 4 billion years—this new floating rock is only expected to orbit the Earth once, beginning its trip Sept. 29 before breaking off from its gravitational pull on Nov. 25.

Researchers Carlos de la Fuente Marcos and Raúl de la Fuente Marcos explained the event in the journal Research Notes of the AAS, writing, “Earth can regularly capture asteroids from the Near-Earth object (NEO) population and pull them into orbit, making them mini-moons.”

Some have debated whether the asteroid even qualifies as a mini-moon due to its relatively small size—clocking in at 33 feet wide—as well as brief stay in Earth’s orbit.