Earth’s Newest Quasi-Moon: asteroid 2025 PN7 identified
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| (NASA two moons Earth asteroid) Image Credit: ESA |
The object was first observed on 2 August 2025 by the Pan‑STARRS1 survey at the Haleakala Observatory in Hawaii, and the research was recently published in Research Notes of the AAS.
Subsequent analysis of archival data suggests the object has followed a co-orbital path with Earth for about 60 years and may remain in that state for approximately another 60-70 years, as there are reports confirming that this new Quasi Moon will stay around the Earth until 2083.
With an estimated diameter of around 19 metres (≈62 ft) the asteroid ranks as the smallest and least stable quasi-satellite known to date.
The object belongs to the Arjuna class of near-Earth asteroids — bodies with orbits very similar to Earth’s.
Key orbital parameters: semi-major axis approximately 1.003 AU, eccentricity ~0.108, inclination about 2° relative to Earth’s orbital plane.
Despite its appearance as a “moon-like” companion, 2025 PN7 is not gravitationally bound to Earth; it orbits the Sun in resonance with Earth, causing it to remain near our planet in relative terms.
The timespan during which 2025 PN7 remains a quasi-satellite is estimated at about 128 years in total (≈60 years in the past plus ≈68 years ahead), making it far less stable than some other known co-orbital objects.
According to researchers, the asteroid remained undetected for decades because of its small size, faint brightness (magnitude ~26) and unfavourable observing windows.
The AAS study authors explained more by saying:
"Over three decades later, it is now widely accepted that such objects are natural and constitute a secondary asteroid belt that occupies the region in which the Earth–moon system orbits around the sun, defining the Arjuna dynamical class. The Arjunas with the most Earth-like orbits can experience temporary captures as mini-moons of our planet."
French amateur astronomer Adrien Coffinet flagged the object’s potential co-orbital status in August 2025 via an analysis sent to the Minor Planet Mailing List.
While 2025 PN7 poses no known threat to Earth, the discovery offers a rare case to study the orbital dynamics of near-Earth objects that share Earth’s orbit rather than crossing it.
Such bodies may serve as accessible targets for future space missions or planetary-defence research, given their relative proximity and Earth-like motion.
Modelled orbital evolution indicates 2025 PN7 will eventually disengage from the quasi-satellite state and transition to a different co-orbital arrangement (such as a horseshoe orbit) under the influence of solar and planetary perturbations.
Ongoing observations will refine its trajectory, physical characteristics and potential for further study, but officially, the Earth now has two moons, and the 2nd one is not like the first one we can see every day.
