Earth Will Get a Temporary Mini Moon – Will You See Two Moons In the Sky?

(The featured image is illustrative.)

Starting on 29 September, the Earth will have two natural satellites at once: the familiar Moon and a ‘’mini-moon” – a small asteroid that will orbit our planet for 53 days.

The mini-moon is actually a small asteroid, named 2024 PT5, that was discovered on 7 August by the Asteroid Terrestrial-Impact Last Alert System (ATLAS). The asteroid is only ten metres long – a tiny space object compared to the Moon, which is around 3,500 km in diameter. 

This asteroid is on a trajectory that will bring it close enough to Earth to be temporarily captured by the planet’s gravity, and will orbit it from 29 September to 25 November.

Is It the First Mini-Moon Ever Orbited Earth?

According to the paper published in Research Notes of the AAS: “Earth can regularly capture asteroids from the Near-Earth object (NEO) population and pull them into orbit, making them mini-moons”. So, this event is not unique. For example, in 2006 asteroid named 2006 RH120 orbited Earth for one year. Another one was stuck in the gravitation of our planet for about two years – from 2018 till 2020.

Actually, asteroid  2024 PT5 will not do a full loop around Earth before disappearing in the outer space, and there’s therefore some debate about if it is truly a mini-moon.

Amateur astronomer Tony Dunn published a simulation of the movement of asteroid 2024 PT5 around the Earth in the coming months on the social network X.

Object From Arjuna Asteroid Belt or a Piece of Moon?

Observing the asteroid’s trajectory allowed researchers to confirm that it’s not space debris and trace it back to its origin. They concluded that it most likely came from the Arjuna asteroid belt, a group of many asteroids whose orbits are very Earth-like in character.

However, there is another version of the origin of this space object. Paul Chodas, director of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory (JPL), told the New York Times that the asteroid’s behaviour suggested that it’s “possibly a piece of ejecta from an impact on the moon”. So, the additional moon may actually be a fragment of the original moon.

Can We See Asteroid 2024 PT5 from Earth?

No. Unfortunately, this asteroid is too small to spot with the naked eye or even with a regular, powerful telescope. Moreover, it will have a magnitude of 22, meaning it is very faint. In order to see an object in space with the naked eye, it must have a magnitude of 6, preferably less. 

According to astronomers, asteroid 2024 PT5 will next fly close to Earth on 9 January 2025 and again in 2055. Maybe by then, the technologies will allow us to observe it without any special equipment. Who knows?