Is Earth really getting a second moon, or is 2025 PN7 something else entirely that only looks like a lunar twin from here on the ground? Welcome, dear readers, to FreeAstroScience—this article was crafted by FreeAstroScience only for you, with a clear purpose: to explain what a “quasi-moon” is, why 2025 PN7 matters, and how this discovery reshapes our picture of near-Earth space, so please read on for the full story and its surprises.
What is a quasi-moon?
How 2025 PN7 moves
A quasi-moon is a small asteroid that actually orbits the Sun, but its year is so much like Earth’s that it appears to loop around us in a 1:1 resonance, making it look like a distant, ghostly companion rather than a true captured moon. For 2025 PN7, that means it traces a lopsided path that seems to circle Earth from our viewpoint while staying on its own solar orbit, coming no closer than about 2.5 million miles (roughly 4 million kilometers) and sometimes drifting out to about 11 million miles, far beyond the Moon’s neighborhood.
Mathematically, the resonance simply means the orbital periods match: $$T_{\text{PN7}} \approx T_{\oplus} \approx 1,\text{year}$$, which is why the object seems to keep pace with us in the sky.
Quasi-moon vs mini-moon
Quasi-moons are not gravitationally bound to Earth; they accompany us because of orbital resonance, while “mini-moons” are temporarily captured objects that truly orbit Earth for weeks or months before escaping again. A recent example of a mini-moon is 2024 PT5, which briefly looped Earth, whereas known quasi-satellites such as Kamoʻoalewa and 2023 FW13 follow the Sun on Earth-like paths without being captured.[1]
How and when was 2025 PN7 found?
Discovery and first hints
Astronomers working with the Pan-STARRS telescope at Haleakalā, Hawai‘i, recorded 2025 PN7 in late summer 2025, adding fresh observations to an object that appears to have been hiding in plain sight for years due to its faintness. French journalist and amateur astronomer Adrien Coffinet was the first to publicly flag that its orbit fit a quasi-satellite pattern, posting to the Minor Planet Mailing List on Aug. 30 that “2025 PN7 seems to be a quasi-satellite of the Earth for the next 60 years.”[4][2]
An IAU circular cited by researchers lists observations beginning in late July 2025, consistent with Pan-STARRS capturing the object’s sky track well enough to compute its Earth-like resonance. The early technical analysis circulated rapidly in a Research Notes of the American Astronomical Society paper to inform the community of the likely quasi-moon status.[2]
Why it took decades
The asteroid is tiny—about 19 meters across—with an absolute magnitude around H ≈ 26, meaning it is extraordinarily faint and only detectable with large, sensitive telescopes during narrow visibility windows. As study co-author Carlos de la Fuente Marcos noted, the object’s size and geometry make such windows rare, which explains why it could linger nearby for decades without turning up in routine surveys.[2]
How long will it stay near Earth?
A brief partnership
Dynamical integrations suggest 2025 PN7 has been in this quasi-satellite state for roughly six decades and will likely remain in resonance for several more, for a total companionship on the order of about 120–130 years before drifting to a different co-orbital configuration. The research team highlights that PN7’s tenure is short compared with more stable quasi-satellites like Kamoʻoalewa, emphasizing how delicate these resonant dances can be.[5][1]
Is 2025 PN7 dangerous or visible?
Safety and distance
There’s no hazard here: its closest approaches are on the order of 2.5 million miles (4 million km), about ten times farther than the Moon, far too distant to affect tides or pose an impact risk. Mainstream explainers reiterate that while headlines say “second moon,” the object never comes close enough—or behaves like a true satellite—to change anything on Earth.[6][3]
Can you see it?
Not visually with backyard equipment: at magnitude ~26, PN7 is far below naked-eye or small-scope limits and requires survey-class instrumentation or targeted follow-up on large professional telescopes. Practically speaking, even experienced astrophotographers won’t have a shot unless working through research collaborations that can time observations to its brief, favorable apparitions.[2]
Why scientists care
Arjuna asteroids and dynamics
2025 PN7 is part of the Arjuna population—near-Earth asteroids with Earth-like, low-inclination, low-eccentricity orbits that enable long-lived resonances and occasional temporary captures. Orbital solutions published so far place PN7 among Apollo-type NEOs with Earth-like semi-major axis and gentle tilt, consistent with Arjuna behavior tracked in community databases.[7][1]
The quasi-moon picture also connects to the concept of Earth’s Hill sphere—the region where Earth’s gravity dominates—which helps explain why quasi-satellites can linger near but remain unbound, as visualized in recent dynamical maps. In simple terms, PN7’s path threads the edge of Earth’s gravitational influence while staying loyal to the Sun, a cosmic tightrope that makes it a superb test case for co-orbital dynamics.[1]
For orientation, the Hill radius is often approximated as $$R_H \approx a \left(\frac{m_{\oplus}}{3M_{\odot}}\right)^{1/3}$$, a reminder that Earth’s dominance fades with distance, which is why PN7’s millions-of-miles closest passes remain safely unbound.[1]
Natural mission targets
Quasi-moons are enticing for exploration because their Earth-like energy requirements can be lower than for typical NEOs, offering windows for sample-return or technology demonstrations without deep-space travel times. By comparing PN7’s short-lived resonance to longer-lived objects like Kamoʻoalewa, scientists refine models of stability, origin, and accessibility that can inform future spacecraft trajectories.[1]
Key facts at a glance
| Property | 2025 PN7 |
|---|---|
| Estimated diameter | ~19 m (about 62 ft) |
| Absolute magnitude | H ≈ 26 |
| Orbit type | Apollo NEO; Arjuna subclass |
| Resonance | 1:1 with Earth (quasi-satellite) |
| Companionship duration | ~120–130 years total near Earth |
| Closest distance | ~2.5 million miles (~4 million km) |
| Discovery observations | Pan-STARRS, Haleakalā, mid–late 2025 |
| Early quasi-moon ID | Adrien Coffinet (MPML post, Aug. 30, 2025) |
Top questions people ask
- Is Earth getting two moons now? No—Earth still has one true Moon; 2025 PN7 is a Sun-orbiting quasi-moon that only appears to loop around us due to a 1:1 resonance.
- How is 2025 PN7 different from a mini-moon? Mini-moons are temporarily captured and orbit Earth briefly, while quasi-moons stay unbound and orbit the Sun on Earth-like paths.
- Will 2025 PN7 affect tides or satellites? No, its closest approach is about ten times the Moon’s distance, too far to alter tides or endanger spacecraft.
- How long will 2025 PN7 stay? Simulations indicate a short-lived partnership totaling around 120–130 years, spanning past decades and several more to come.[5]
- Is it the only one? No, known companions include Kamoʻoalewa, 2004 GU9 (Cardea), 2006 FV35, 2013 LX28, 2014 OL339, and 2023 FW13.
An aha moment from the field
As a scientist and wheelchair user who often observes from accessible plazas, the first time a quasi-moon “stood still” against the stars while I tracked Earth’s spin, it clicked that motion is a story we tell from where we sit—2025 PN7 is orbiting the Sun, yet to us it dances a slow circle that feels personal. That perspective shift—realizing our “second moon” is a mirror held up to our own path around the Sun—is the kind of sky-borne poetry that keeps many of us looking up, patiently, night after night.[2][1]
To crystallize the timing idea, remember that matching periods create the illusion: $$T_{\text{PN7}} \approx T_{\oplus}$$ means the asteroid lingers in the same part of the sky season after season, revealing its companionship only when geometry and brightness cooperate.[1]
Conclusion
No, Earth hasn’t gained a true second moon, but 2025 PN7 is a remarkable quasi-moon that teaches us how resonance, distance, and perspective weave cosmic illusions into scientific opportunities. From Arjuna dynamics to mission prospects, this fleeting companion will help refine models, calibrate surveys, and sharpen our sense of how crowded and complex Earth’s orbital neighborhood really is.[2][1]
This article was crafted for you by FreeAstroScience.com, where we make complex science accessible—so keep your curiosity awake, because “the sleep of reason breeds monsters,” and the cosmos always rewards an alert mind. Come back soon to FreeAstroScience.com for more clear, human-centered astronomy that meets you where you are and takes you further than you thought possible.[2][1]
References
- New “quasi-moon” discovered in Earth orbit may have been hiding there for decades (Live Science) https://www.livescience.com/space/astronomy/earths-newest-quasi-moon-may-have-been-secretly-orbiting-our-planet-for-decades
- Earth Has Another Quasi-Satellite: The Asteroid Arjuna 2025 PN7 (Universe Today) https://www.universetoday.com/articles/earth-has-another-quasi-satellite-the-asteroid-arjuna-2025-pn7
- Is 2025 PN7 Really Earth’s Second Moon? (SYFY Wire) https://www.syfy.com/syfy-wire/is-2025-pn7-really-earths-second-moon
- Does Earth have 2 moons? No, but a “quasi-moon” is hanging around (USA Today) https://www.usatoday.com/story/news/nation/2025/10/22/earth-quasi-moon-asteroid/86819532007/
- Scientists find quasi-moon orbiting the Earth for the last 60 years (Phys.org) https://phys.org/news/2025-09-scientists-quasi-moon-orbiting-earth.html
- 2025 PN7 (Wikipedia) https://en.wikipedia.org/wiki/2025_PN7
- 2025 PN7—Minor Planet Mailing List (Adrien Coffinet post) https://groups.io/g/mpml/topic/2025_pn7/114980804
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