There’s a new moon in town — sort of.
The much-discussed 2025 PN7, dubbed Earth’s “second moon,” is officially a quasi-moon, according to NASA, which confirmed the designation this week.
First spotted by researchers over the summer, the newly discovered rock isn’t a true moon but rather an asteroid that travels around the sun in near-lockstep with Earth — making it appear, from our perspective, as if it’s orbiting our planet.
But unlike the actual moon, 2025 PN7 is just shadowing us in a synchronized path, says Northeastern University assistant professor Jacqueline McCleary, an observational cosmologist.
The celestial object belongs to the Arjuna asteroid group, a collection of “near-Earth objects” that move in resonance with Earth. Because 2025 PN7 is not gravitationally bound to our planet like the moon is, it’s not a “true” moon.
But according to McCleary, there’s no simple rule for what counts as a moon and what doesn’t. She says that astronomers have long quibbled about criteria — debating everything from size cutoffs to orbital stability.
Read more at Northeastern Global News
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