Evrim Yazgin
Cosmos science journalist
An asteroid is approaching, but it won’t crash into Earth. Instead, it’ll be our planet’s little companion for 2 months before continuing on its merry way.
2024 PT5 is about 11m wide. The asteroid was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in South Africa on 7 August.
In a study published in the journal Research Notes of the AAS, a pair of asteroid dynamics researchers calculated the asteroid’s size, speed and path. The researchers determined the asteroid would complete a single orbit around Earth over 53 days before being flung back into outer space.
The asteroid will start its orbit of Earth on 29 September. The bus-sized “mini moon” is scheduled to depart on 25 November.
Many asteroids follow a similar journey, falling into partial or full elliptical orbits around our planet as they pass by. One such “quasi-moon” is an asteroid discovered last year which astronomers believe has been orbiting Earth for more than 2,000 years.
Other quasi-moons make much briefer visits, like the 5m 2006 RH120 which orbited Earth for about a year and 2020 CD3 which was a mini companion of our planet for several years before leaving us in May 2020.
The researchers also believe they know from where 2024 PT5 is joining us based on its trajectory.
“Such orbital elements are consistent with those of the Arjunas, a sparsely resonant population of small NEOs [near-Earth objects] in a secondary asteroid belt found surrounding the path followed by the Earth–Moon system,” they write.
