Not one, but Earth has a 2nd moon!

February 29: It was on February19 that astronomers at the Catalina Sky Survey in Arizona spotted a dim object moving quickly across the sky somewhere close to earth. The same object was then observed by researchers at six more observatories around the world who confirmed the presence of what can now be considered a mini moon.

This ‘mini-moon’ is actually an asteroid, measuring between 1.9 and 3.5 metres (6.2 and 11.5 feet) in diameter, that was temporarily captured by our planet’s gravity. Named 2020 CD3, we picked up our second moon some time in 2017 but, given how vast the sky is and how dark the moon is, it never caught anyone’s attention, until now.

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

Kacper Wierzchos, a senior research specialist for the Catalina Sky Survey and co-discoverer of the mini moon said, “In the nights after the discovery, we kept following the object to try to determine its orbit. Our calculations showed that, most likely, the object was circling the sun and Earth’s gravity snatched it into our planet’s orbit sometime in 2017.” How did the mini moon go unnoticed for years? First, the sky is vast, and telescopes have limited time dedicated to searching for asteroids, Wierzchos said. He also cited the mini moon’s faintness and highly variable orbit.

Incidentally, this isn’t the first-time earth has had an additional moon, albeit temporarily. In 2006, the 2006 RH120 remained within the earth’s gravitational pull between September 2006 and June 2007 before it managed to wriggle free. Astronomers have said that the new mini-moon orbit isn’t stable, which means, eventually, the 2020 CD3 might catapult itself away from Earth, just like the 2006 RH120 asteroid.