Earth captures a new mini-moon: Asteroid 2024 PT5 orbits until November
From today, 29 September, until 25 November, Earth will have two natural satellites. In addition to the Moon, asteroid 2024 PT5, also known as the mini-moon, will orbit the Earth.
Asteroid 2024 PT5 was identified on 7 August of this year using the ATLAS (Asteroid Terrestrial-impact Last Alert System), which detects potentially Earth-threatening asteroids. The object is about 10 meters in diameter, making it too small and not bright enough to observe with the naked eye or even through amateur telescopes.
Professors Carlos de la Fuente Marcos and Raúl de la Fuente Marcos from the Complutense University of Madrid published their research findings in The Research Notes of the AAS. They reported that Earth can regularly capture asteroids from near-Earth objects (NEO) and pull them into orbit, creating mini-moons. They stated that the shape of asteroid 2024 PT5 was discovered during routine monitoring of newly identified objects.
How can Earth capture an asteroid and turn it into a mini-moon? This is not a very common phenomenon, although quite a few asteroids fly close to our planet, sometimes even at distances shorter than the distance to the Moon. Usually, they pass Earth without becoming moons, continuing their journey in their orbit.
He added that even the smallest celestial bodies can be considered natural satellites if they enter Earth's orbit and remain there for a while. Certain conditions must be met for this to be possible.
Prof. Carlos de la Fuente Marcos from the Complutense University of Madrid, quoted by Space.com, explained that to become a mini-moon, an approaching body must get to a distance of about 2.8 million kilometres from Earth and move "slowly," at a speed of about 2,200 kilometres per hour.
Next time in 2051
The expert added that the celestial bodies that have been in Earth's orbit for longer have so far been two objects: asteroid 2006 RH120, which was the second moon of Earth from July 2006 for almost a year, and 2020 CD3, which - according to researchers - orbited our planet for up to three years. There are also examples of short-term captures, such as 1991 VG and 2022 NX1, which, as a mini-moon, will likely return in 2051.
After leaving Earth's orbit, asteroid 2024 PT5 will be closest to Earth on 9 January 2025. It will then leave the planet's vicinity to return to the asteroid belt. It will reappear near Earth only in 2055.
