An asteroid spent roughly 60 years quietly shadowing Earth's journey around the Sun before astronomers noticed it in 2025. Orbital calculations show 2025 PN7 has been locked in step with our planet si
Astronomers have identified 2025 PN7, a small asteroid that has been in a 1:1 orbital resonance with Earth for approximately 60 years. While it shadows Earth's path around the Sun, it is classified as a quasi-satellite rather than a second moon.
Why it matters
This discovery demonstrates the power of 'precovery' techniques in modern astronomy, allowing scientists to trace the history of celestial objects using archived data.
2025 PN7 is a tiny Sun-orbiting quasi-satellite whose 60-year relationship with Earth comes from orbital modelling, while precovery images now trace its measured history to 2013.
Pan-STARRS 1 detected the asteroid now called 2025 PN7 on 2 August 2025. Within weeks, orbital calculations showed that the tiny object had already been travelling in step with Earth for about 60 years.
It had not gone entirely unseen. Telescopes had recorded it in older images, but no one knew that those faint points belonged to an Earth quasi-satellite until the 2025 observations provided an orbit that could be traced backwards.
The distinction matters: 2025 PN7 is not a second moon. It orbits the Sun rather than Earth, while moving through a temporary 1:1 resonance that keeps its average pace close to ours.
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