| Summary |
|
Astronomers have identified a small asteroid, 2025 PN7, that appears to be temporarily locked in step with Earth’s orbit around the sun. The discovery, made on August 2, 2025, by the Pan-STARRS telescope in Hawaii, reveals a 19-meter-wide object that has been accompanying Earth since the mid-20th century and is expected to remain nearby until about 2083.
The asteroid belongs to the Apollo group, a class of near-Earth objects whose elongated orbits cross Earth’s and extend toward Mars. Its current path keeps it close enough to act as a “quasi-moon,” a companion that orbits the sun but appears to move alongside Earth due to their synchronized motion.
Unlike the moon, which is bound by Earth’s gravity, quasi-moons orbit the sun on nearly the same timeline as Earth. From our perspective, they seem to loop or hover near the planet in a stable but temporary arrangement.
2025 PN7 follows what astronomers describe as a horseshoe-shaped orbit. The sun’s gravity dominates, but Earth’s pull subtly alters its path, causing it to drift back and forth across our orbit. This gravitational balance keeps it near us for decades without risk of collision.
Models show that 2025 PN7 has been sharing Earth’s orbital neighborhood since around 1965. Its distance from Earth varies from about 299,000 kilometers to as far as 17 million kilometers. The asteroid’s motion is influenced by Jupiter’s gravity, which gradually shifts its path over time.
At just 19 meters across, 2025 PN7 is faint and hard to detect without powerful telescopes. Scientists estimate it will remain stable for nearly six more decades before slowly drifting away, possibly toward an orbit near Venus.
Early observations suggest that 2025 PN7 is likely a rocky or stony asteroid, possibly originating from the main asteroid belt between Mars and Jupiter. Like other Apollo-type asteroids, it may have been nudged inward after ancient collisions.
Future spectroscopy will help determine its composition, whether it’s primarily silicate rock, metal, or a mix of both. Such data could offer clues about how material moves through the inner solar system and what resources small asteroids may hold.
Tracking objects like 2025 PN7 helps refine our understanding of orbital mechanics and near-Earth object behavior. Quasi-moons provide insight into how asteroids interact with planets and how gravitational resonances form.
The asteroid poses no danger to Earth, but studying its orbit improves our ability to model others that might pass closer in the future. These findings also aid planetary defense research, as predicting the paths of small bodies is key to identifying real threats.
Astronomers plan to monitor 2025 PN7’s brightness and rotation using both optical and radar observations. NASA’s upcoming NEO Surveyor mission, designed to detect near-Earth objects in infrared light, may capture more detailed data once operational.
If its orbit remains stable, 2025 PN7 will continue to share Earth’s path for nearly 60 more years before it drifts away. Until then, it joins a short list of known quasi-moons, including 3753 Cruithne and Kamo‘oalewa, reminding us that even near our planet, space is full of quiet companions.
