Earth has a new “mini-moon” after an asteroid has joined our orbit. The object, known as 2024 PT5, has been chasing after us for years. Now, it has become close enough to be pulled in by our gravity. It will stay with us until November, when it will stop being bound to Earth and we will leave it behind, then it will stay on its new orbit around the Sun.
Mini-moons happen when an asteroid slowly approaches Earth in such a way as to be taken around more by our planet’s gravity than the usually much more powerful pull of the Sun. They are usually formed out of asteroids or other natural objects that are floating around space. But it is possible for them to be human-made, as when pieces of space junk get caught in our gravity.
The newly discovered example, 2024 PT5, was only spotted last month by scientists as part of the Asteroid Terrestrial-Impact Last Alert System. The 2024 in its name refers to its year of discovery. While the mini-moon is not thought to pose any risk, it is an exciting addition to our cosmic neighbourhood.
Researchers reported in a paper published last month in the journal Research Notes of the AAS under the title ‘A Two-month Mini-moon’ that the object was expected to take a horseshoe-like route, being pulled into our orbit before falling back out again, probably around 25th November. It will then depart our neighbourhood in January, with a possibility of flying by again in 2055.
While the object can be seen with dedicated telescopes, it is too small and dim to be spotted with the naked eye. Similar instances of mini-moons joining Earth have occurred in the past, such as in the case of 2022 NX1, which joined Earth as a mini-moon in 1981 and then returned in 2022.
It is relatively rare for Earth to host mini-moons in the way 2024 PT5 has, with other planets like Jupiter being more common hosts due to their larger mass and stronger gravitational pull. Such occurrences highlight the fascinating interplay between celestial bodies in our solar system.
Other planets also have their mini-moons, with different dynamics at play based on their mass and gravitational pull. The discovery of 2024 PT5 adds a fascinating chapter to our understanding of the cosmos and the various objects that inhabit our celestial neighbourhood.