A digital image showing a close-up of an asteroid near Earth.Photo credit: Live Science
Earth is about to welcome a temporary visitor in the form of a "mini-moon," an asteroid that will be trapped by our planet's gravity for around two months. This small space rock, named 2024 PT5, is about the size of a school bus, measuring 33 feet (10 meters) in diameter. It will zip by Earth on Sunday and get caught in the planet's gravitational pull, orbiting for nearly two months before moving away again in late November.
The asteroid was first discovered in August by astronomers at the Complutense University of Madrid, using a telescope in Sutherland, South Africa. Although it may be exciting news for space enthusiasts, it won't be visible to the naked eye or through standard amateur telescopes. According to Carlos de la Fuente Marcos, one of the astronomers involved in the discovery, the asteroid can only be observed with research-grade telescopes.
Richard Binzel, an astronomer at the Massachusetts Institute of Technology (MIT), said that these brief visits by mini-moons are more common than we may think. However, because these objects are usually very small and challenging to detect, they often go unnoticed. "This happens with some frequency, but we rarely see them because they’re very small and very hard to detect," Binzel explained. The last known mini-moon was detected in 2020, but advances in survey capabilities are allowing astronomers to spot these tiny objects more frequently.
The discovery of 2024 PT5 was published by the American Astronomical Society, showcasing the work of Carlos de la Fuente Marcos and Raul de la Fuente Marcos. Binzel, who wasn't directly involved in the research, noted that it's not yet clear whether the asteroid originated from space or if it could possibly be a chunk of the moon that broke off and ended up in Earth's orbit. While it’s intriguing to ponder the rock’s origin, there isn’t enough data at the moment to determine its exact source.
After completing an almost full two-month journey around Earth, the mini-moon will escape Earth's gravitational hold on November 25 and continue its journey through space. This won’t be the last we hear of it, though—scientists predict that it will swing by our planet once again in 2055.
These mini-moons, although brief in their visits offer fascinating insights into the dynamics of small objects that are temporarily captured by Earth’s gravity. Such discoveries highlight the importance of advanced telescopes and observational technology, which help astronomers keep track of objects that were previously too elusive to detect. While 2024 PT5 won’t be putting on a visible show for skywatchers, it serves as a reminder of how dynamic our cosmic neighbourhood can be.
