Earth has had two moons in the past. One of the mini-moons has visited twice and will return in 27 years

Earth now officially has two moons after its gravity caught an asteroid. Our planet captured asteroid 2024 PT5 on Sunday, September 29, which has now become our mini-moon. However, do you know that this is not the first time Earth has had a mini-moon?

The asteroid was discovered on August 7 by the Asteroid Terrestrial-Impact Last Alert System (ATLAS). Carlos and Raúl de la Fuente Marcos, researchers at Spain’s Universidad Complutense de Madrid, were the first to spot it and published their findings in Research Notes of the AAS. 

These space rocks regularly travel around the sun like other asteroids. But when they come near Earth, sometimes the planet’s gravity pulls them in. It is definitely a rare event, however, not the first. 

The two astronomers say in their paper that our planet has had a mini-moon previously as well. The first such recorded event happened in 1981. A cosmic body, called 2022 NX1, was temporarily captured by Earth’s gravity. The mini-moon returned in 2022. Both times, it stayed only for a short period of time. It will return to Earth in 2051.

Another short-lived mini-moon, as per the authors, was 1991 VG. It was captured for a short time in 1992 February during a flyby. Both of the above never completed a full revolution of Earth

However, in 2006 we had a mini-moon that stayed with us for a full year. Asteroid 2006 RH120 remained gravitationally bound to Earth from till July 2007 after getting caught in July 2006. 

Another asteroid that stayed with us for many years was 2020 CD3. It remained in orbit for years and escaped early in 2020 May.

Our latest mini-moon is similar to the 2022 NX1. It will not complete a full orbit of Earth and will remain with us only for a few days before flying away on November 25. 2024 PT5 lives in the Arjuna asteroid belt. Space rocks living in this region follow orbits similar to Earth’s, which is about 93 million miles from the sun.

Some of the objects from the Arjuna asteroid belt can approach Earth at an extremely close range of around 2.8 million miles. 

It is not possible to see the mini-moon since it is too small and dim. Amateur telescopes and binoculars are not going to be enough to see it. Our Moon is about 2,159 miles in diameter, while the new entrant is believed to be just 37 feet wide.