Earth Has a Second Moon — And It Could Stay for Another 300 Years
For decades, astronomers have been fascinated by the possibility that Earth might occasionally capture small objects into temporary orbits. But recent studies suggest something even more astonishing: a small quasi-moon, also known as a quasi-satellite, may remain in Earth’s gravitational embrace for at least another 300 years.
This object, often referenced as 2023 FW13, moves around the Sun in sync with Earth, creating the appearance of a “second moon.” Unlike our permanent Moon, this body doesn’t orbit Earth directly. Instead, it follows a delicate orbital dance influenced by Earth, the Moon, and the Sun. According to researchers at the Jet Propulsion Laboratory (JPL), the object’s orbit is stable enough that it has likely accompanied Earth for centuries and will continue to do so far into the future. (See the NASA JPL overview here: NASA asteroid database).
The concept of quasi-moons is not new. In fact, Earth has captured temporary companions before. The famous case of 2020 CD3, which became a mini-moon for a couple of years before drifting away, was confirmed by the International Astronomical Union (IAU). (Reference: IAU Minor Planet Center).
What makes 2023 FW13 exceptional is its long-term orbital stability. A study published by astronomers using data from the Pan-STARRS survey shows that this small rocky body has been orbiting in resonance with Earth since at least 100 B.C. and is predicted to remain for several more centuries. (Source: Pan-STARRS Project).
Although not a true moon, this quasi-satellite offers scientists a unique opportunity to study Earth’s gravitational interactions and the behavior of near-Earth objects. As monitoring improves through observatories and NASA programs like NEO Surveyor, we may discover even more hidden companions quietly sharing our cosmic neighborhood.
Earth may not officially have two moons—but for the next 300 years, it certainly has company.
