Earth may have been orbited by a ‘mini-moon’ for about three years, according to a team of astronomers. The fact has just been discovered, as researchers observed the object rotating around the planet.
The cosmic body, which is estimated to be around the size of a car, was spotted on February 15th, and it is possible to be an asteroid caught by Earth’s gravity. The satellite, believed to be between 1.90 (6.2 feet) and 3.50 meters (11.4 feet) in size, was noticed by Kacper Wierzchos and Teddy Pruyne of the Catalina Sky Survey program, which is funded by NASA.
“BIG NEWS,” wrote Kacper Wierzchos on Twitter. “The Earth has a newly captured/possibly mini-moon object called 2020 CD3″, which could be a type C (carbonaceous, therefore very dark) asteroid.”
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
Weirzchos added that it’s motion pattern shows it approached our planet’s orbit about three years ago.
A mini-moon is an asteroid that gets caught by Earth’s gravity. The cosmic object goes into an odd orbit around the planet because of the triple gravitational pulls of the Earth, the Moon, and the Sun. After a brief period in this intricate orbit, a gravitational tug can then draw it out, and back into the Sun’s orbit.
The asteroid observed this month would be the second known space rock to orbit Earth after another ‘asteroid mini-moon’ was spotted in 2006, known as RH120, also discovered by the Catalina Sky Survey. It rotated around the Earth from September 2006 to June 2007.
The Smithsonian Astrophysical Observatory’s Minor Planets Centre, which gathers data on small objects in the Solar System, said that ‘no link to any known man-made object has been established,’ suggesting that it was most likely an asteroid caught by Earth’s gravity.
The asteroid 2020 CD3 will probably leave Earth’s orbit in April, as Grigori Fedorets, a researcher at Queen’s University in Belfast, said: “It is moving away from the Earth-Moon system as we speak.”