Asteroid 2025 PN7 identified as Earth quasi-satellite

Astronomers have identified an asteroid, designated 2025 PN7, that has been shadowing Earth in a quasi-satellite state for approximately 60 years. While first detected by the Pan-STARRS 1 telescope on August 2, 2025, orbital calculations and archival data reveal the object has been following a similar path to Earth since the mid-1960s.

Researchers Carlos de la Fuente Marcos and Raúl de la Fuente Marcos detailed the findings in a paper titled ‘Meet Arjuna 2025 PN7, the Newest Quasi-satellite of Earth’. The object is not a true moon; instead, it follows a heliocentric path with a 1:1 resonance, meaning it completes one revolution around the Sun every 366 days, closely matching Earth’s orbital period. This creates the illusion of a satellite without the object ever entering Earth’s gravitational sphere.

Using precovery techniques—re-examining archival images with updated orbital models—scientists were able to trace the asteroid's path backward. Evidence of the object appeared in a 2018 Dark Energy Camera image, though it remained unidentified at the time. The European Space Agency estimates the asteroid's size to be between 14 and 30 meters.