Earth has a new friend — and it's been waiting for us to notice it for decades.
In a new study published in the journal Research Notes of the American Astronomical Society, astronomers report the discovery of a mysterious object that appears to be a "quasi-moon," or a small asteroid that orbits the Sun, but in an arc that puts it near our planet for an extended period of time.
Think of it as a cosmic situationship; though it's been following us for around 60 years, the object isn't gravitationally bound to Earth. In another 60 years, it's expected to drop the quasi-moon act and be sucked back into its grander orbit around the Sun.
Designated 2025 PN7, the near-Earth asteroid one of the few quasi-moons that have ever been discovered, providing a glimpse of the strange ways that wayward objects can move throughout a busy star system.
"The Solar System is full of surprises so we keep looking," study co-lead author Carlos de la Fuente Marcos told CNN. "For Earth's neighborhood, the existence of 2025 PN7 suggests that there may not exist a lower limit to the size of a quasi-satellite."
The object is tiny. While exact dimensions are hard to pin down, de la Fuente Marcos suspects it could be around 98 feet across, though in the study it's estimated to be as small as 62 feet across, EarthSky noted. According to de la Fuente Marcos, it's currently the smallest known quasi-moon that's orbited near our planet.
Intriguingly, 2025 PN7 comes from a family of near-Earth objects called the Arjuna asteroids that all exhibit unusually Earth-like orbits despite the fact they don't actually orbit our planet. The first of these was detected in 1991, making 2025 PN7 the newest known family member.
The astronomers believe that this latest quasi-moon is an asteroid from the main belt that wandered close to our planet, though it's too early to say for certain.
Others of its ilk have origins closer to home. Last year, astronomers found that the quasi-moon Kamo'oalewa, first discovered in 2016, is likely a chunk of the Moon proper that was blasted off by an asteroid impact at least a million years ago.
Our planet is also host to mini-moons, which are similar objects that temporarily get captured by Earth's gravity. Some of the Arjuna asteroids have briefly become mini-moons, like one called 2024 PT5 that entered Earth's orbit for a little over a month last year. But this fate doesn't appear to be in the cards for 2025 PN7.
Right now, the quasi-moon's closest approach brings it within 186,00 miles of Earth, which puts it over half way to the orbit of the Moon. This distance, paired with its relatively tiny size, made it incredibly difficult to detect.
"It can only be detected by currently available telescopes when it gets close to our planet as it did this summer," de la Fuente Marcos told CNN. "Its visibility windows are few and far between. It is a challenging object."
Sadly, the little interloper won't be around for much longer. Once it leaves its circular orbit near the Earth in about six decades, it'll drift into a horseshoe orbit that takes it as far as 185 millions miles from us. And before it does, we should study it up close, de la Fuente Marcos argues.
"These asteroids are relatively easy to access for unmanned missions and can be used to test planetary exploration technologies with a relatively modest investment," he told CNN.
More on asteroids: Scientists Find Evidence of Flowing Water on Giant Asteroid