Space and Physics
An asteroid heading towards Earth is set to have an unusual fate: instead of smashing through our planet’s atmosphere, it’s likely to become trapped in orbit and become a mini-moon. It will be a swift visit, however, and is likely to only remain in Earth's gravitational grasp for two months.
The asteroid, named 2024 PT5, was discovered on August 7 and measures around 10 meters (33 feet) in diameter.
Two astronomers from the Complutense University of Madrid, Carlos de la Fuente Marcos and Raúl de la Fuente Marcos, have studied the orbit of the object and concluded that it will become captured in Earth’s orbit for a brief window between September 29 and November 25. It will then fall back into orbit of the Sun and continue its journey through the Solar System.
In other words, for a total of 56.6 days, Earth will have two moons (well, one proper Moon and one mini-moon, to be precise).
The study notes that 2024 PT5 is “unlikely to be artificial,” meaning it’s probably not just a piece of space junk, which can be mistaken for mini-moons. The researchers suggest it could be an Arjuna asteroid, defined as a near-Earth object with a similar orbit to our planet. They’re named after an ancient prince of the Kuru Kingdom, located in present-day India, and a central character in the Hindu epic Mahābhārata.
Unfortunately, you’re unlikely to catch a glimpse of the mini-moon while it’s welcomed by Earth’s embrace. According to the NASA JPL Small-Body Database, 2024 PT5 has an absolute magnitude of 27.6, which is very dim and won’t be visible through most amateur telescopes.
So-called mini-moons have graced Earth’s presence before. Asteroid 2022 NX1 was a short-lived mini-moon in 1981. It quickly left our planet’s grasp, before returning as a mini-moon in 2022. It’s estimated that it will return as such in 2051 once again.
2024 PT5 is expected to make multiple mini-moon visits too. The asteroid will return to Earth's orbit in January 2025 before quickly leaving and returning again in 2055.
The study is published in the journal Research Notes of the American Astronomical Society.
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