You’ve probably spent your whole life looking up at that big, glowing white rock in the sky and thinking it was the only one. Honestly, most of us did. But late in 2024, the headlines started screaming that Earth has 2 moons, and suddenly everyone was squinting at the night sky trying to find a second light.
It wasn't there. Well, it was, but you couldn't see it.
The "second moon" wasn't some long-lost twin or a secret base. It was a tiny space rock called 2024 PT5. Astronomers from the Complutense University of Madrid, specifically Carlos de la Fuente Marcos and Raúl de la Fuente Marcos, spotted this thing using the ATLAS (Asteroid Terrestrial-impact Last Alert System) telescopes in South Africa. It wasn't permanent. It was what scientists call a "mini-moon," a temporary visitor that got snagged by Earth's gravity for a couple of months before heading back out into the solar system.
The Reality of Earth’s Temporary Second Moon
When people hear "Earth has 2 moons," they usually imagine a Star Wars landscape with two giant orbs hanging over the horizon. Reality is a bit more subtle. 2024 PT5 was only about 33 feet wide. That's roughly the size of a city bus. Compare that to our permanent Moon, which is over 2,000 miles wide.
You weren't going to see it with your naked eye. You couldn't even see it with a standard backyard telescope. You needed professional-grade observatory equipment just to get a glimpse of this tiny boulder.
It stayed with us from September 29 to November 25, 2024.
The mechanics of this are actually pretty cool. Think of Earth like a massive magnet moving through a room full of metal shavings. Most of the shavings just fly past, but occasionally, one enters at just the right speed and angle to get caught in a loop. That’s a horse-shoe orbit. 2024 PT5 didn't even complete a full circle around Earth. It just sort of did a "U-turn" in our gravitational well before the Sun’s stronger pull yanked it back home.
Why 2024 PT5 Wasn't Just Space Junk
Sometimes, these "moons" turn out to be old rocket boosters. We’ve been burned before. In 2020, an object labeled 2020 SO was caught in Earth's orbit, and everyone got excited until NASA realized it was actually a Centaur rocket booster from the 1966 Surveyor 2 mission.
📖 Related: Sweden School Shooting 2025: What Really Happened at Campus Risbergska
2024 PT5 was different. Its orbital characteristics and light reflection patterns matched a natural asteroid. It belongs to the Arjuna asteroid belt, which is a group of space rocks that follow orbits very similar to Earth's. Because they move at about the same speed and distance from the Sun as we do, they are the perfect candidates for becoming temporary mini-moons.
This Happens Way More Often Than You Think
We tend to think of space as this empty vacuum, but it’s actually kind of crowded. Earth is constantly dancing with small objects. We’ve had confirmed mini-moons before, though they don't happen every day.
Take 2006 RH120. It stuck around for about a year between 2006 and 2007. Then there was 2020 CD3, which was discovered in February 2020 and had actually been orbiting Earth for a few years before we even noticed it. It finally escaped our gravity in March 2020.
Basically, Earth is a bit of a cosmic collector.
There are also "quasi-satellites." These are even weirder. An object like Kamo'oalewa (469219 Kamoʻoalewa) is technically orbiting the Sun, not Earth, but its path stays so close to us that it looks like it’s orbiting Earth. It’s been our "buddy" for centuries and will probably stick around for hundreds more. Some scientists even think Kamo'oalewa might be a chunk of our actual Moon that got knocked off during an ancient impact.
The Math Behind Getting "Captured"
It’s all about velocity. If an asteroid is moving too fast, it zips right past us. If it’s moving too slow or gets too close, it hits the atmosphere and becomes a spectacular (or dangerous) fireball.
To become a mini-moon, the asteroid has to be:
👉 See also: Will Palestine Ever Be Free: What Most People Get Wrong
- Relatively close (within about 2.8 million miles).
- Moving slowly (around 2,200 miles per hour).
- Approaching at a low angle.
When these stars—or asteroids—align, Earth’s gravity briefly overpowers the Sun’s influence. For a few weeks or months, the object belongs to us.
What Scientists Learn from These Tiny Visitors
You might wonder why anyone cares about a 33-foot rock that’s only here for two months. It’s not just for the "Earth has 2 moons" headlines. These objects are incredibly valuable for future space exploration.
Mining asteroids is a big topic in "New Space" circles. If we want to get resources like water or metals from space, it's a lot easier to go to a rock that’s literally orbiting our planet than to chase one down across the solar system. Mini-moons are the perfect "practice targets" for retrieval missions.
There’s also the "Early Warning" factor. By tracking things as small as 2024 PT5, agencies like NASA’s Planetary Defense Coordination Office get better at spotting things that might actually pose a threat. If we can see a bus-sized rock from millions of miles away, we have a much better chance of seeing the "city-killer" sized rocks before they get too close for comfort.
The Mystery of the Origin
Where do these things come from? Most are just stray bits of the asteroid belt. But the chemical composition of some of these visitors suggests they might be lunar ejecta.
When a massive meteorite hits our Moon, it kicks up a lot of dust and rock. Because the Moon has low gravity and no atmosphere, some of that debris reaches escape velocity. It enters orbit around the Sun, occasionally crossing paths with Earth again millions of years later. In a way, when Earth has 2 moons, the second one might just be a piece of the first one coming back for a visit.
What Happens Next?
2024 PT5 is gone for now, but it isn't gone forever. Based on the calculations by the Madrid team, it's expected to make another close pass in 2055. It’s a long-distance relationship.
✨ Don't miss: JD Vance River Raised Controversy: What Really Happened in Ohio
The reality is that we likely have mini-moons all the time that we just aren't seeing. Our technology is finally getting good enough to spot them. Projects like the upcoming Vera C. Rubin Observatory in Chile are expected to find dozens, maybe hundreds, of these temporary satellites. We’re going to have to get used to the idea that our "one moon" system is actually a lot more fluid.
It's a weird thought. We live on this giant blue marble, and we think we know everything about our immediate neighborhood. Then a rock the size of a bus shows up, hangs out for eight weeks, and leaves without most people even knowing it was there. It's a reminder that space is busy, dynamic, and full of surprises.
How to Stay Updated on Earth's Next Mini-Moon
If you want to be ready for the next time someone says Earth has 2 moons, you don't need a PhD, but you do need to know where to look.
Follow Minor Planet Center (MPC) Announcements
The MPC is the official clearinghouse for all small body discoveries. When a new potential mini-moon is found, this is where the raw data appears first. It’s technical, but it’s the source of truth.
Use Space Tracking Apps
Apps like SkySafari or websites like Heavens-Above often update their databases with newly discovered near-Earth objects. While you might not see the mini-moon, you can track its position relative to the stars.
Watch for "Close Approach" Lists
NASA’s JPL (Jet Propulsion Laboratory) maintains a Small-Body Database. Keep an eye on the "Close Approaches" section. Any object with a very low "relative velocity" (V-rel) has a chance of being captured.
Support Citizen Science
The ATLAS project and others rely on wide-field surveys. Many amateur astronomers contribute by confirming the orbits of these objects after they are first spotted. If you have a high-end telescope and a CCD camera, you could actually help track the next visitor.
The next time you look at the Moon, remember it’s just the only one big enough to stay. There’s almost certainly something else up there with us right now—small, dark, and just passing through.