Newly-discovered #asteroid 2024 PT5 is about to undergo a “mini-moon event” when its geocentric energy becomes negative from September 29 – November 25. pic.twitter.com/pVYAmSbkCF

— Tony Dunn (@tony873004) September 10, 2024

Asteroid mini-moon animation via Tony Dunn on X.

Earth to get an asteroid mini-moon for 2 months

Earth’s gravity will temporarily capture a newly discovered asteroid named 2024 PT5, creating a mini-moon. According to researchers Carlos de la Fuente Marcos and Raúl de la Fuente Marcos, the asteroid should loop around Earth from September 29 until November 25, 2024. However, the asteroid will never complete one revolution of Earth, so it’s considered a temporarily captured flyby as opposed to a temporarily captured orbiter. Either way, this asteroid mini-moon will hang around until it once again breaks loose from Earth’s grasp.

The ATLAS survey in South Africa discovered the asteroid on August 7, 2024.

The scientists published their study in the non-peer-reviewed Research Notes of the AAS in September 2024.

Mini-moon and asteroid PT5

The asteroid and soon-to-be mini-moon is approximately 33 feet (10 meters) in size. It’s likely part of a population of near-Earth asteroids called Arjunas. These objects have orbits around the sun that are similar to Earth’s. Asteroid 2024 PT5’s close approach to our planet at a relatively low velocity is what will allow Earth’s gravity to temporarily alter its path. According to the study, for 56.6 days the little asteroid will change from orbiting the sun to orbiting Earth. But then the sun pulls it back into a heliocentric orbit. The asteroid will then have another somewhat close flyby of Earth on January 9, 2025, before:

leaving the neighborhood of Earth shortly afterward, until its next return in 2055.

Will you see it?

Unfortunately, our new little mini-moon will be too dim to see. It will be no brighter than magnitude 22, which is even out of reach of backyard telescopes.

This is not the first time Earth has acquired a mini-moon. In fact, asteroid 2024 PT5 is following a similar course as an earlier asteroid, 2022 NX1. The asteroid 2022 NX1 became a mini-moon of Earth for a brief time in 1981 and 2022. That asteroid will return as a temporary mini-moon again in 2051.

Bottom line: Earth will get a mini-moon for two months when the 33-foot-wide asteroid 2024 PT5 makes a close pass of our planet and makes a temporary loop about us.

Source: A Two-month Mini-moon: 2024 PT5 Captured by Earth from September to November

Read more: Say goodbye to Earth’s mini-moon on February 1 and 2