Earth May Have Six Extra ‘Quasi-Moons’ Like 2025 PN7

There’s a brand new moon on the town — kind of. 

The much-discussed 2025 PN7, dubbed Earth’s “second moon,” is formally a quasi-moon, in response to NASA, which confirmed the designation this week. 

First noticed by researchers over the summer time, the newly found rock isn’t a real moon however reasonably an asteroid that travels across the solar in near-lockstep with Earth — making it seem, from our perspective, as if it’s orbiting our planet.

But not like the precise moon, 2025 PN7 is simply 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 group of “near-Earth objects” that transfer in resonance with Earth. Because 2025 PN7 is just not gravitationally certain to our planet just like the moon is, it’s not a “true” moon.

But in response to McCleary, there’s no easy rule for what counts as a moon and what doesn’t. She says that astronomers have lengthy quibbled about standards — debating every part from measurement cutoffs to orbital stability.

Most astronomers desire the time period “natural satellite” to “moon” or “moonlet,” which haven’t any universally accepted definitions, McCleary says. 

“Within this, there is an enormous amount of variation, even within our own solar system: from Mars’s moons Phobos and Deimos, which are little more than captured asteroids, to the Galilean satellites of Jupiter, which are almost the size of Earth and have features like subsurface oceans and volcanoes,” McCleary says. 

The quasi-moon has possible been our shut neighbor for some 60 years, specialists say. But the asteroid is so small that it will possibly hardly be seen with out a big telescope that can also be able to scanning giant areas of the sky, says Northeastern University astrophysicist Jonathan Blazek.  

Researchers from the University of Hawaii, working at a analysis facility in Haleakala, Hawaii, found the quasi-moon in July utilizing the Pan-STARRS telescope, which Blazek says is optimized for locating new objects in our photo voltaic system, in addition to different astronomical “transients” — cosmological phenomena that change, reminiscent of supernovae.

“The Rubin Observatory, which just started taking data earlier this year, and with which I am involved, is an even larger telescope that will find many new solar system objects,” he says. 

Blazek and McCleary notice that there are different such partial, momentary or quasi moons hanging across the planet. In reality, at the least six of them. 

“These objects are all on similar orbits to the Earth and remain reasonably stable over many years,” Blazek says.

In 2024, Earth had a quick companion in 2024 PT5, an asteroid that loosely orbited the planet for a couple of months, McCleary says.  

But 2025 PN7 is predicted to hold round Earth till 2083, at which level it can drift off into area.

“In the long term, the orbits will drift, and the quasi-moons will move away,” Blazek says. “2025 PN7 is expected to stick around for roughly another 60 years.”

Experts say 2025 PN7 could have nearly no gravitational influence on Earth as a result of it being fairly small, astronomically talking. 

Blazek estimates that the quasi-moon is “roughly the size of a small office building,” in comparison with the moon, which he calculates is “about a quadrillion (10^15) times more massive.”

“At only 20 meters across, it’s far too small to have a measurable effect on the Earth’s tides or anything else,” McCleary says.