Astronomers from the United States have found that planet Earth has had another Moon orbiting it for more than three years approximately.
The Minor Planet Centre announced the discovery of the celestial body on February 26 after calculating its orbit.
The Minor Planet Centre, working under the auspices of International Astronomical Unit, is the official worldwide organisation in charge of collecting observational data for minor planets, comets and outer irregular natural satellites of the major planets.
The new Moon, however, is extremely tiny, estimated to have a diameter panning a maximum of six meters, and is essentially an asteroid.
Scientists Theodore Pruyne and Kacper Wierzchos, who first spotted it on February 15 using the telescope at Mount Lemmon Observatory, believe the minimoon won’t be with us for too long.
They confirmed that the temporary moon that has been named 2020 CD₃, would be leaving the Earth’s orbit very soon, which could be as early as April 2020.
BIG NEWS (thread 1/3). Earth has a new temporarily captured object/Possible mini-moon called 2020 CD3. On the night of Feb. 15, my Catalina Sky Survey teammate Teddy Pruyne and I found a 20th magnitude object. Here are the discovery images. pic.twitter.com/zLkXyGAkZl— Kacper Wierzchos (@WierzchosKacper) February 26, 2020
(2/3) The object has just been announced by the MPC and its orbit shows that it entered Earth's orbit some three years ago. Here is a diagram of the orbit created with the orbit simulator written by Tony Dunn: pic.twitter.com/2wsJGtexiO— Kacper Wierzchos (@WierzchosKacper) February 26, 2020
(3/3) The object has a diameter between 1.9 - 3.5 m assuming a C-type asteroid albedo. But it's a big deal as out of ~ 1 million known asteroids, this is just the second asteroid known to orbit Earth (after 2006 RH120, which was also discovered by the Catalina Sky Survey).— Kacper Wierzchos (@WierzchosKacper) February 26, 2020
This minimoon, however, got captured into an orbit located at quite a distance from our permanent moon, while approaching the Earth. It is quite common for such asteroids to orbit the earth for a few years before breaking away to claim its own orbit around the Sun. The 2020 CD₃ is likely on its final loop, given it has been orbiting the Earth unnoticed for quite a few years now.