October 24, 2025 | 02:59 pm
TEMPO.CO, Jakarta - Earth has gained a temporary cosmic companion. Astronomers recently discovered an asteroid, 2025 PN7, that appears to be orbiting alongside our planet, earning it the nickname of a “quasi-moon” or temporary moon.
Unlike the real Moon, 2025 PN7 does not orbit the Earth directly. Instead, it orbits the Sun, following a path so similar to Earth’s that it seems to travel alongside us for decades.
According to a paper published in IOP Science in September 2025, the asteroid will remain near Earth until 2083 before drifting away.
What Exactly Is a Quasi-Moon?
Phil Nicholson, an astronomy professor at Cornell University, explained that quasi-moons follow orbits very similar to Earth’s. “As a result, they sometimes 'keep company' with the Earth for years, or even decades,” he said, as quoted by ABC News on October 22, 2025.
NASA data show that 2025 PN7 is extremely small and faint, with a magnitude of around 26, meaning it is invisible to the naked eye and can only be observed with powerful telescopes.
Zoe Ponterio, manager of the Spacecraft Planetary Image Facility at Cornell University, said that although the asteroid looks like it’s orbiting Earth, it is not a true satellite. “Its orbit is oval-shaped, so sometimes it's closer to the Sun than Earth, while sometimes it's farther,” she explained.
When nearer, 2025 PN7 moves slightly faster than Earth; when farther, it slows down. This shifting motion makes it appear to hover near Earth in the sky.
"With the Earth and quasi-moon taking turns passing each other, the quasi-moon appears to be moving around us," Ponterio said.
From Companion to Horseshoe Orbit
Ponterio noted that the asteroid’s orbit will eventually shift into what astronomers call a “horseshoe orbit.” In this pattern, the object appears to swing back and forth around Earth’s path before slowing down at its outermost point.
With this discovery, scientists have now identified seven known quasi-moons orbiting near Earth. However, Ponterio emphasized that the public will not be able to see them. “TThis object is far too small, dark, and distant for us to see without very powerful telescopes, so the average person will not see a second moon in the sky,” she said.
How It Was Found
Asteroid 2025 PN7 was first detected on August 29, 2025, by the Pan-STARRS telescope at the Haleakal Observatory in Hawaii. Archival data suggest that it has been moving in a similar orbit for at least 60 years.
Kelle Cruz, a professor of physics and astronomy at Hunter College in New York, said the discovery underscores the complexity of our solar system.
“This discovery exemplifies that our Solar System is comprised of far more than just the familiar planets we learn about as school children,” she noted.
Cruz added that large-scale observation projects like Pan-STARRS and the LSST survey at Chile’s Rubin Observatory will likely lead to many more discoveries in the coming years.
“This new quasi-moon is just the beginning of a flood of new discoveries to come.,” she said.
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