What's next: A lot more observations.
Only one other mini-moon has ever been observed with a telescope and it orbited the Earth for 11 months before flying off into space.
Earth shares its neighborhood with a coterie of objects.
The last mini-moon, the 2006 RH120, stayed in the Earth's orbit for about a year, from 2006 to 2007.
That would also happen with 2020 CD3, although we don't know when.
The scientists who discovered the object on February 15 estimate that, because of the instability of its path through space, the minimoon will likely leave Earth's orbit sometime in April. When it was initially spotted three years ago, the asteroid had already been around for a century. Specialists at Catalina help NASA discover and track near-Earth objects that could be potentially hazardous to the planet. This object, with a diameter estimated between 2 to 3 metres (6.5 to 10 feet), was also discovered by Catalina Sky Survey scientists. While excitement about the discovery is growing, it is important to keep in mind that this moon isn't as impressive as our main satellite.
2020 CD3 will likely leave Earth's orbit in April, Grigori Fedorets, a researcher at Queen's University in Belfast, told New Scientist magazine. This is not enough to compare it to the real Moon, the only natural satellite of the Earth. 2020 CD3 is very small and faint.
The tug of war between them for dominance would pull gravity back and forth triggering massive volcanic activity.
A small asteroid has been orbiting Earth for 3 years, astronomers say. So while they appear to have a relationship with Earth, they are actually just orbiting the Sun in company with, but independently of, the Earth.