From the February 2010 issue

Could a near-Earth asteroid enter into orbit around Earth?

Mark Phelan, Abilene, Texas
By | Published: February 22, 2010 | Last updated on May 18, 2023
April 2010 asteroid 2006 RH120
In June 2006, Earth captured tiny asteroid 2006 RH120. This space rock became a temporary Earth satellite, sticking around for roughly 1 year.
Peter Birtwhistle, Great Shefford Observatory

While the Moon is Earth’s only known natural satellite, a few small near-Earth asteroids have become temporary Earth satellites.

However, if a massive third body, like the Moon, gravitationally nudged a small object, or if an asteroid-Moon collision ejected an object from the Moon’s surface, it could then become a long-term Earth satellite.