Our solar system is filled with moons both big and small. The ice giants, Uranus and Neptune, have 28 and 16 moons, respectively. Jupiter and Saturn have hundreds of moons between them and even Pluto, a diminutive dwarf planet, has five moons. Mars has two, small and potato shaped, and Earth has just the one, impressive as it might be.

Perhaps that’s why our planet, lonely with only its single companion, tends to collect temporary cosmic friends. Recently, astronomers detected the presence of a relatively new quasi-moon called 2025 PN7, which appears to orbit our planet. The discovery of the object, also called Buwan, was published in Research Notes of the American Astronomical Society, but reports that the object is Earth’s “second moon” have been exaggerated.

Meet 2025 PN7, Earth’s newest quasi-moon

You may have heard elsewhere that Earth has a new moon. Not the moon phase which happens roughly once a month, but a new natural satellite orbiting our planet. It’s true, but only sort of, and only from the right point of view.

Earth’s only true natural satellite is the Moon, but every so often some much smaller object falls into temporary companionship with the planet, joining a class of objects commonly quasi-moons. The asteroid 2025 PN7 is the latest to be discovered. Quasi-moons actually orbit the Sun, but because of their unique paths through space, they appear to circle Earth from our perspective on the planet. At its farthest point from Earth, 2025 PN7 gets about 11 million miles away and it only gets as close as 2.5 million miles, roughly 10 times the distance between Earth and the Moon.

For more on quasi-moons and mini-moons: Earth’s Quasi-Moon Kamo’oalewa Might be Literal Offspring from the Moon Say Hello to Our Quasi-Moon, 2014 OL339 The Earth Has a New Minimoon! But Not for Long…

Astronomers discovered 2025 PN7 at the Pan-STARRS observatory in Hawaii back in August 2025. A search through archival observations suggests the asteroid entered into its current orbital relationship with Earth about 60 years ago, and it’s expected to hang out for another 58 years. It was able to evade detection for so long because it’s small and dim, with an estimated diameter between 60 and 90 feet.

What is a quasi-moon?

Fortunately for our lonely planet, Earth won’t be left alone after 2025 PN7 departs in 2083. Our planet has a handful of other quasi-moons, some of which are sticking around for a while. There’s 164207 Cardea, which will stick around for another 600 years. There’s 469219 Kamo’oalewa (also known as 2016 HO3, pictured above), a 50-meter rock that might be part of the Moon itself, ejected after an ancient impact. And there’s 2023 FW13, has been in its quasi-moon orbit for at least 2,000 years, and will be for at least 1,700 more.

Not to be confused with mini-moons like 2024 PT5, which directly orbit our planet for short periods, quasi-moons orbit the Sun. As they orbit, they zoom ahead or fall behind, dipping inside of or soaring outside of Earth’s orbit. As a result, from our point of view, they appear to trace circles around our planet, but it’s an illusion.

It’s more like Earth and 2025 PN7 are both cars fighting for first place on a racetrack. As one car or the other surges ahead and through a series of regular lane changes, it appears as if 2025 PN7 is driving circles around Earth, while they both run laps around the Sun. Just like in any race, something chaotic is bound to happen eventually.

Over time, many quasi-moons transition into a trojan orbit where they circle a gravitationally stable point known as a Lagrange point ahead of or behind the planet. Otherwise, they fall into a horseshoe orbit, which oscillates back and forth along Earth’s path, tracing a horseshoe with Earth between its two end points. The asteroid 2025 PN7 is destined for a horseshoe when its relatively brief period as a quasi-moon comes to an end.

Hang out with another cosmic visitor in Resident Alien, streaming now on SYFY.