Astronomers have discovered a new cosmic companion for Earth, an asteroid named 2025 PN7, which has become our planet’s “quasi-moon.” According to a study published last month in IOP Science, this newly discovered space rock will remain in Earth’s orbit around the Sun until 2083.
While it may sound like Earth has gained another moon, scientists emphasize that 2025 PN7 is not a true moon. Unlike the Moon, which directly orbits Earth, quasi-moons orbit the Sun just like regular asteroids – but their orbits are very similar to Earth’s, making them appear to travel alongside our planet for decades.
Not a Real Moon, But It Looks Like One
Cornell University astronomy professor Phil Nicholson explains, “Quasi-moons are not true moons and do not actually revolve around Earth, although sometimes they appear to do so.”
He further clarifies that these objects orbit the Sun but remain in sync with Earth due to their similar orbital paths. As a result, they stay near our planet for years or even decades, giving the illusion of orbiting Earth.
Zoe Ponterio, manager of Cornell University’s Spacecraft Planetary Image Facility, told ABC News that 2025 PN7 is called a quasi-moon because, from our point of view, it seems to circle Earth. “Its orbit is oval-shaped, so it sometimes moves closer to the Sun and sometimes drifts farther from Earth,” she said.
When the asteroid moves closer to the Sun, it speeds up; when it moves away, it slows down, making it appear as though it’s looping around Earth. “When Earth and the quasi-moon take turns crossing each other, it looks to us as if it’s orbiting us,” Ponterio explained.
A Temporary Celestial Visitor
Astronomers predict that over the coming decades, 2025 PN7’s orbit will slowly shift and eventually take on a “horseshoe” shape. This means it will appear to swing back and forth across the sky as it moves between Earth’s inner and outer orbital paths.
According to researchers from Northeastern University, this is not Earth’s first quasi-moon. So far, scientists have identified six other quasi- or temporary moons orbiting near Earth at different times.
In fact, as recently as 2024, a small asteroid was temporarily trapped in Earth’s orbit for about 2 months, a short-lived visitor nicknamed a “mini-moon.” However, 2025 PN7 is expected to remain near Earth for nearly six decades, making it a much longer companion.
When and How It Was Found
The object was first detected on August 29, 2025, using the Pan-STARRS telescope at the Haleakalā Observatory in Hawaii. After analyzing previous astronomical data, scientists found evidence that 2025 PN7 has actually been aligned with Earth’s orbit for more than 60 years, but it was only recently identified as a quasi-moon.
Too Dim to See with the Naked Eye
According to NASA, 2025 PN7 is extremely faint, with a brightness of only magnitude 26, meaning it is invisible without powerful telescopes. Professor Nicholson notes that quasi-moons are generally very small, much smaller than our natural Moon, and can only be studied with specialized instruments.
What Makes Quasi-Moons Special
Quasi-moons like 2025 PN7 provide astronomers with a fascinating opportunity to study how Earth interacts with nearby space objects. They also help researchers understand orbital dynamics, how gravity between the Earth, Sun, and smaller bodies creates complex patterns of motion.
While 2025 PN7 won’t pose any threat to Earth, its discovery adds another chapter to our planet’s ongoing relationship with the cosmos.
So, for the next half-century, Earth will have not one, but two companions on its journey around the Sun, our familiar Moon, and its quiet, shadowy cosmic twin: the quasi-moon 2025 PN7.
