On 19 February, astronomers at the Catalina Sky Survey in Arizona spotted a dim object moving quickly across the sky. Over the next few days, researchers at six more observatories around the world watched the object, designated 2020 CD3, and calculated its orbit, confirming that it has been gravitationally bound to Earth for about three years.

This is just the second asteroid known to have been captured by our planet as a mini-moon – the first, 2006 RH120, hung around between September 2006 and June 2007 before escaping.

Our new moon is probably between 1.9 and 3.5 metres across, or roughly the size of a car, making it no match for Earth’s primary moon. It circles our planet about once every 47 days on a wide, oval-shaped orbit that mostly swoops far outside the larger moon’s path.

The orbit isn’t stable, so eventually 2020 CD3 will be flung away from Earth. “It is heading away from the Earth-moon system as we speak,” says Grigori Fedorets at Queen’s University Belfast in the UK, and it looks likely it will escape in April.

-----Comments----- So cool. Maybe there's a way we could mine asteroids this way? Share your thoughts please.