Meet Earth’s newest quasi-moon, recently discovered 2025 PN7

Meet quasi-moon 2025 PN7

You might recall that in late 2024, Earth gained a temporary mini-moon, an asteroid that partially orbited our planet for about two months. Now astronomers have discovered another temporary companion to Earth, but this time it’s a quasi-moon. The Pan-STARRS observatory on Haleakala in Hawaii first spotted the quasi-moon, named 2025 PN7, on August 29, 2025. Older data revealed that 2025 PN7 has been in this particular orbit for about 60 years and will stay in this orbit for about another 60 years before the tug of the sun once again releases it from its quasi-moon status.

But 2025 PN7 isn’t the first known quasi-moon in our solar system, and it’s not the first for Earth, either. Astronomers have discovered a slew of quasi-moons for Earth before, including Cardea, Kamo‘oalewa and four others. In fact, China launched a mission in 2025 – Tianwen-2 – to collect and return samples from Kamo‘oalewa in 2027.

What is a quasi-moon?

So what is a quasi-moon? A quasi-moon is not truly orbiting Earth, it just looks like it from our perspective. More accurately, a quasi-moon is basically sharing an orbit with us. But that orbit it not exactly the same as ours. It does not always stay ahead or behind us in orbit, so sometimes we see it in front of us and sometimes we see it behind us.

Check out this illustration of the first quasi-moon discovered, 2002 VE 68 (or 524522 Zoozve), a quasi-moon of Venus. You can see how it has its own orbit around the sun, but from the perspective of anyone on Venus, it appears to be orbiting Venus.

And here’s another illustration of how a quasi-moon appears to move. This is Kamo‘oalewa, or 2016 HO₃. It’s orbiting the sun, but also appears as if it’s orbiting Earth.

More on 2025 PN7

Unsurprisingly, quasi-moon 2025 PN7 is exceedingly dim, which has helped it escape detection until now. It’s about magnitude 26. That puts it far out of range of amateur telescopes. And, also unsurprisingly, it’s small, relatively speaking. The space rock is approximately 19 meters (62 feet) in diameter.

The quasi-moon Kamo‘oalewa is likely a piece of the moon blasted out in an impact. In contrast, the speed of 2025 PN7 indicates it’s likely a captured asteroid from the main belt.

Over time, the orbit of 2025 PN7 switches from a horseshoe orbit to its current quasi state, and it will return to a horseshoe orbit once more. Okay, so now what’s a horseshoe orbit?

A horseshoe orbit is also an orbit around the sun, but from our perspective it appears to trace a horseshoe shape. So eventually, 2025 PN7 will appear to approach us from behind, then slow down and reverse direction before catching up again from the front. Check out the horseshoe orbit animation here.

And the little space rock’s future is still up in the air. As Alan Harris wrote on the Minor Planet Mailing List:

Some future close encounter with the Earth could put it on an orbit that intersects either (or both) Mars or Venus.

Bottom line: Earth has a newly discovered quasi-moon! The little space rock 2025 PN7 shares an orbit with Earth and appears to orbit our planet.

Via Minor Planet Center

Earth’s asteroid mini-moon a chunk of the moon?

Was asteroid Kamo’oalewa blasted from this moon crater?

See Haleakala National Park, Stunning from Summit to Sea