A new celestial discovery has astronomers buzzing: a small space rock, quietly trailing Earth for decades, has been confirmed as a quasi-moon. Known as PN7, this mysterious object has been moving in tandem with our planet since the 1960s. Its presence, revealed through high-powered telescopes, challenges our assumptions about how many moons Earth really has.
A Strange Companion In Earth’s Orbit
The discovery of PN7 marks yet another addition to Earth’s growing list of shadow satellites — cosmic hitchhikers that share our orbit around the Sun. A new paper published in the Research Notes of the American Astronomical Society confirms PN7’s unusual dance, a looping trajectory that sometimes places it ahead of Earth, and at other times, just behind. Unlike our familiar Moon, these objects aren’t bound by gravity to our planet; instead, they move in a delicate gravitational balance, co-orbiting with us like silent travel companions through the Solar System.
When Ben Sharkey, an astronomer at the University of Maryland, first heard about PN7, as scientists now call it, their first thought was: “Oh cool, another one.” His reaction captures the growing realization among astronomers that our planet may always have more temporary moons than anyone ever imagined. Observations from telescopes like Pan-STARRS in Hawaii, which first detected PN7, are revealing just how dynamic and populated Earth’s orbital neighborhood really is. Some of these quasi-moons, like Kamoʻoalewa, have remained stable for centuries, while others drift away after only a few decades, pulled by the subtle forces of the Sun and Earth.
Another mini-moon? Maybe. Newly discovered 2025 US6 is officially listed as an asteroid.
Unlike our quasi-moon 2025 PN7, this one is actually bound to Earth, for now.
Its orbit is pure chaos. Enjoy it while it lasts. It’ll probably be demoted to space junk. pic.twitter.com/iKv247l3d5
— Tony Dunn (@tony873004) October 26, 2025
Mini-Moons And Celestial Stowaways
While quasi-moons such as PN7 share Earth’s orbit without being captured, mini-moons go a step further — they become temporary satellites, snared by our planet’s gravity before escaping again into deep space. These fleeting visitors are tiny, fragile, and notoriously hard to spot. Grigori Fedorets, an astronomer at the University of Turku in Finland, explains that most mini-moons are “quite small, like boulders,” which means that they are difficult to detect. So far, only a handful have been confirmed, each lasting less than a year before gravity releases its hold.
What makes PN7 and its kin fascinating is not just their existence, but what they reveal about Earth’s gravitational environment. Scientists suspect that these quasi-moons may be remnants of asteroids disturbed by Jupiter’s immense gravity, fragments of the lunar surface, or even survivors from the chaotic formation of the early Solar System. With more advanced telescopes like the upcoming Vera C. Rubin Observatory, researchers expect a flood of new discoveries that could redefine our understanding of near-Earth space.
Credit: Research Notes of the American Astronomical Society
The Mystery Of Origin And Future Discoveries
The story of PN7 also ties into a broader exploration effort aimed at understanding where these wandering bodies come from. Some quasi-moons, like Kamoʻoalewa, exhibit surface properties strikingly similar to our Moon’s, suggesting that they might be ancient lunar debris blasted into space by collisions long ago. Others could be wayward asteroids pushed into Earth’s orbit by planetary resonances.
Upcoming missions, including one led by China, are already en route to collect samples from these quasi-moons, hoping to answer one of the biggest questions in planetary science: are these cosmic hitchhikers leftovers from Earth’s own birth, or foreign visitors merely passing through? Whatever their origins, they stand as silent reminders of how dynamic and restless our cosmic neighborhood truly is. Each discovery adds another layer of wonder to the story of our planet’s hidden companions — a narrative where even a tiny, building-sized rock can reshape our understanding of what it means to orbit the Sun alongside Earth.
