Earth Gains a Second ‘Moon’ – Asteroid 2025 PN7 Discovered
Astronomers have confirmed Earth has acquired a second ‘moon’ – an asteroid called 2025 PN7 that has been quietly orbiting near our planet for nearly 60 years. The space rock qualifies as a ‘quasi-moon’, traveling in sync with Earth around the sun.
Key Takeaways
- Asteroid 2025 PN7 discovered as Earth’s new quasi-moon
- Has been Earth’s companion for nearly 60 years
- May remain in orbit until 2083
- One of only eight confirmed quasi-moons
- Smallest known quasi-moon discovered to date
Discovery and Identification
Researchers at the University of Hawaii first spotted 2025 PN7 during a routine telescope survey on August 29. The Pan-STARRS observatory on Haleakala volcano captured initial observations. Archival data later revealed the celestial object has been Earth’s companion for several decades.
What is a Quasi-Moon?
2025 PN7 is a quasi-moon – a celestial object that travels almost exactly in sync with Earth. While not a true moon bound by Earth’s gravity, it keeps pace with our planet and revolves around the sun in such perfect harmony that it appears to shadow Earth throughout its orbit.
Quasi-moons differ from temporary mini-moons like 2024 PT5, which orbited Earth for about two months in 2024 before being blasted away by our primary moon. The newly discovered 2025 PN7 may remain with us until 2083 if its current orbit holds. It joins very few known quasi-moons near Earth, including Kamo’oalewa, believed to be an ancient lunar fragment.
Size and Visibility Challenges
Earth’s second moon is small and faint, explaining why it remained undetected for so long. Astronomers estimate it measures about 98 feet (30 meters) across and approximately 62 feet (19 meters) in diameter.
According to Carlos de la Fuente Marcos, researcher at Complutense University of Madrid, “It can only be detected by currently available telescopes when it gets close to our planet as it did this summer. Its visibility windows are few and far between. It is a challenging object.”
The space rock is the smallest known quasi-moon to orbit near Earth. At its closest approach, 2025 PN7 swings within 299,337 kilometers of our planet, compared to the Moon’s average distance of 384,400 kilometers.
Astronomers have confirmed only eight quasi-moons in total, making this discovery particularly significant for understanding Earth’s celestial companions.
