Scientists have discovered a previously unknown quasi-moon that’s been shadowing Earth’s orbit for decades, undetected, and will likely remain there for a few decades more. The quasi-moon, named 2025 PN7, is one of around seven quasi-satellites that share Earth’s orbit around the Sun. The Pan-STARRS observatory in Hawaii spotted the quasi-moon on August 2, according to a paper published in Research Notes of the American Astronomical Society. The discovery prompted scientists to search through archival data for earlier signs of 2025 PN7, and they found the near-Earth asteroid in images that date back to 2014. The data suggests that the space rock has been in a stable orbit for 60 years, and will remain on a similar path for another 60 years before drifting out of sync with our planet’s orbit around the Sun. Meet 2025 PN7 2025-PN7 is around 62 feet (19 meters) wide, and it’s between 2.8 million miles and 37.2 million miles away from Earth. It was found in the constellation Piscis Austrinus, which can be seen in Southern Hemisphere skies. The newly spotted space rock belongs to an elite group of near-Earth asteroids. Earth has only one natural satellite—you may have heard of the Moon—but asteroids on similar orbits to our planet are influenced by its gravity. As a result, these quasi-satellites appear to accompany Earth on its path around the Sun, without actually orbiting the planet itself. That means they aren’t captured by Earth’s gravity; they simply keep pace as our planet moves around its host star. Accordingly, they’re more like temporary traveling companions than actual moons. Quasi-moons are not to be confused with mini-moons. Mini-moons are temporarily captured by Earth’s gravity, orbiting our planet for a short period—anywhere from a few weeks to a few months—before freeing themselves from the orbital tug. Last year, a small near-Earth asteroid briefly got caught by Earth’s gravity, becoming the planet’s mini-moon for a brief but exciting two-month stretch. Mini-moons are perhaps more common than quasi-moons. The most famous quasi-moon is Kamoʻoalewa, formally known as 2016 HO3. The elongated near-Earth object was discovered on April 27, 2016, and measures between 131 and 328 feet (40 to 100 meters) across. China’s Tianwen-2 mission, launched in May, is designed to rendezvous with Kamoʻoalewa and collect samples from the quasi-moon, returning them to Earth in 2027 to probe for clues about the origin of the solar system.