That's no moon...

It's a quasi-moon. Or, a quasi-satellite. Whatever you want to call it, it's hanging out near Earth. And it could be the source of some fascinating new science. Guests: Nick Moskovitz, astronomer at Lowell Observatory For show transcripts, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠[email protected]⁠⁠⁠ We read every email. Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members ⁠⁠⁠⁠⁠⁠⁠⁠ Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Speaker 00

  Support for the show comes from TikTok. If you listen to this show, you probably enjoy discovering new things. It is built into the DNA of the show that curiosity is its own reward and that there's always a deeper dive to do. And one place to explore some of the topics we've covered here is TikTok. Whether it's how to forecast volcanic eruptions, strange phenomena that the James Webb Space Telescope picked up near the beginning of time, or a literal deep dive on the ocean's deepest reefs, TikTok has a wealth of fascinating videos just waiting to be discovered. Your next discovery is waiting on TikTok. Learn more at tiktok.com/discovermore.

• 0:49Speaker 01

  This episode is brought to you by Indeed. You're ready to level up your business, but the pressure to find the right person to make that happen is intense. Indeed sponsored jobs can help carry the load. It boosts your job post to help it reach quality talent fast. Cut through the chaos with Indeed sponsored jobs. Get a $75 sponsored job credit at indeed.com/podcast. Terms and conditions apply. Hiring now? Then this is a job for Indeed sponsored jobs.

• 1:19Speaker 00

  Last August, astronomers detected a small object in space. This thing that has been hanging out near us, apparently for decades, doing vaguely moon-like sorts of things. People got excited about it, but there was this kind of terminological kerfuffle around what to call it. In articles, on TikToks, on news shows, people were pretty quick to say that it was not a second moon. But then they would throw out different terms. So people would talk about quasi-moons and quasi-satellites, sometimes also explaining related terms like mini-moons.

• 2:02Speaker 00

  And it all gets a little confusing. So for now, let's just call this object by its name.

• 2:10Speaker 02

  2025 PN7. So it's not the most exciting name.

• 2:16Speaker 02

  I hope somebody comes up with a proper name or a nickname for it at some point. But for now, we just kind of refer to it as PN7.

• 2:23Speaker 00

  This guy's name is Nick Moskovitz, which in my opinion is much better than 2025 PN7. And I reached out to him because he spends time at Lowell Observatory in Flagstaff, Arizona, researching space objects in general. When I asked him if PN7 was a moon or what, he hesitated for a moment. He did tell me PN7 is one of many objects in the general vicinity of Earth.

• 2:51Speaker 02

  These are what we refer to generally as near Earth objects. And they're cleverly named that way because they get close to the Earth. There are almost 40,000 known near Earth objects in the solar system that we track and keep track of.

• 3:08Speaker 00

  But PN7 is maybe a little more special than some near Earth objects. Because there are lots of objects that just kind of whizzed past us, right? Or only cross our paths sometimes. And then there are the objects that stick around for a while. Those can be mini moons which orbit the Earth. Or they can also do what PN7 seems to be doing, which is to say orbiting the sun, but doing it in such a way that keeps it close to the Earth for a while.

• 3:38Speaker 02

  And so I think probably a term that most people in the community would agree on is a quasi-satellite.

• 3:45Speaker 00

  So that's what I'm going to refer to PN7 as, a quasi-satellite. But if you're still confused, that's fair. As I told Nick, I kind of was too. Have you ever seen the QVC clip? Gorgeous.

• 4:01Speaker 03

  Then look at this one. This is what we call Emerald, but really it's more like a sea foam.

• 4:04Speaker 04

  I love that color.

• 4:05Speaker 00

  Where it's like two QVC hosts.

• 4:07Speaker 03

  It almost kind of looks like what the Earth looks like when you're a bazillion miles away from the planet moon.

• 4:12Speaker 00

  And they're going, "The moon is also a star."

• 4:16Speaker 03

  Isn't the moon a star?

• 4:18Speaker 04

  No, the moon is a planet, darling.

• 4:20Speaker 03

  The sun is a star.

• 4:21Speaker 00

  And then someone's like, "No, the moon is a planet."

• 4:24Speaker 03

  Didn't you do that thing in grade school where you had to name the planets? And there was Uranus, and there was Saturn, and the one with the rings, and da, da, da, and then the Earth. And with the... The moon is never in there, dude. It's not a planet. All right, here, look, this is key lime.

• 4:37Speaker 00

  There's something about this that like, sort of reminds me of that vibe.

• 4:41Speaker 02

  100%. This is, this is, I haven't seen that clip. I don't know. It sounds awesome. But when it comes down to it, it doesn't really matter what label you apply to these objects. They're still just interesting things to study. Like, they're doing interesting things that are rare and cool. And we geek out on that and get excited about it and study these things to, to learn something that we didn't know beforehand. So that, that makes it exciting to me.

• 5:07Speaker 00

  So, this is unexplainable. I'm Byrd Pinkerton. And you can call objects like this whatever you want. PN7, quasi-moon, quasi-satellite. Just don't call them uninteresting. Because Nick Moskovitz is going to tell us some of the things we can learn from them.

• 5:25Speaker 00

  Also, just in case you were wondering, the QVC house did eventually sort of figure out what the moon is.

• 5:32Speaker 03

  The moon is what?

• 5:35Speaker 04

  A natural satellite.

• 5:37Speaker 03

  The moon is a natural satellite.

• 5:37Speaker 04

  But things live on it. That means it's a planet. I don't know.

• 5:40Speaker 03

  Is that what Google said?

• 5:41Speaker 04

  I don't know what it says.

• 5:42Speaker 00

  No, I don't like that at all. I don't even know what that means.

• 5:44Speaker 03

  I do, I use Google all the time.

• 5:59Speaker 00

  So, you have detected an object in space. Something that seems to be acting like a mini-moon or a quasi-satellite. Congratulations. Now, what can you learn from it? Nick says, kind of the first step is to figure out whether or not it is space trash.

• 6:16Speaker 02

  It turns out that when humans put stuff into space, we leave junk behind. We leave rocket bodies and boosters and, and defunct satellites and things like that. We're not good at cleaning up after ourselves here on Earth and definitely not in space. And pieces of space junk... Hang around the Earth-Moon system in a very similar way. They're doing laps around the Earth, just like some of these natural objects do.

• 6:42Speaker 00

  We're making mini-moons.

• 6:44Speaker 02

  We're making, yeah, we've made a whole population of thousands of mini-moons that are artificial in nature, man-made things.

• 6:51Speaker 00

  But let's say you've poked around, done your homework, and you've determined that this is not just space garbage, which is interesting, but a different kind of interesting from a space object like PN7. If your object is not space trash, you now get to figure out if it is, essentially, a little piece of our actual moon. Like, moon debris.

• 7:15Speaker 02

  We know by looking at the moon, our primary moon, our permanent moon, that it has lots of craters on it. And some of those craters are quite large, tens, if not hundreds, of miles across. When you form a big crater like that, you kick off a lot of ejecta. You think of sort of a, you know, a rock smashing into a pond. You're going to splash a lot of water out of the pond. And the analogy for the moon, when a crater gets formed from an impact on the moon, the ejecta from that gets splashed out into space.

• 7:52Speaker 00

  Studying moon debris like this could potentially teach us about the history of the Earth and of our moon. Nick hopes we might someday be able to trace specific bits of moon debris back to the craters where they came from. And he says that would, in turn, help us check the computer models we have of what happened to the moon in the distant past.

• 8:15Speaker 00

  But if our space object is not moon debris or space junk, then it could also be a third thing.

• 8:24Speaker 02

  An asteroid. It's a chunk of rock that formed around the Sun four and a half billion years ago. It's been floating around the solar system. And by studying these, we're really able to study sort of a time capsule of what's been happening in the solar system for four and a half billion years, which is pretty cool.

• 8:47Speaker 00

  That's what most people think PN7 is. An asteroid that has journeyed over to us and is hanging out for a while. And this kind of space object is scientifically fascinating for a bunch of reasons, which we will get into after some very fascinating ads.

• 9:13Noam Hassenfeld?

  Support for the show comes from Sonos. Hey, Sonos, give me some music.

• 9:20Noam Hassenfeld?

  All right, one of life's great mysteries. You're listening to music in the living room, but you gotta grab something from the kitchen. You don't want to take the speaker with you, but you also don't want to miss that beat drop. And this is where I introduce you to the magic of Sonos. Sonos sent me a couple of speakers to try out, so I've got to move two here in the living room. And then I walk down the hall.

• 9:45Noam Hassenfeld?

  I get in here to the kitchen and I got a brand new Sonos Play right here on the counter. I can open the fridge, grab a seltzer.

• 10:02Noam Hassenfeld?

  And yeah, I didn't miss a second. And I can make each speaker louder or softer in the Sonos app, or if I'm using AirPlay, so I can make it louder in the kitchen without blasting whoever is still in the living room. It's all just easy and it sounds amazing. These speakers are crisp, they've got great bass, and I'm especially impressed with the new Sonos Play. It packs this like truly awesome sound in a much smaller size. So I don't know, if I want to head outside for a minute.

• 10:38Noam Hassenfeld?

  It's super easy and yeah, pretty nice out. Visit sonos.com and build your system. Sonos, love the sound, feel the system.

• 10:53Speaker 00

  Support for the show comes from TikTok. Being curious is endlessly rewarding. There are few better feelings, in my opinion, than asking a question and then having that question lead you down a rabbit hole. It might even be the beginning of a new set of interests that was not on your radar beforehand. Maybe you're looking up at the night sky one night and you start to wonder what the most distant thing you can see with the naked eye is. One place to start searching for answers to a question like that is TikTok. First, you might discover a video about the Andromeda Galaxy. And then, next thing you know, you're learning how to find different stars, or how to identify

• 11:37Speaker 00

  constellations, or how different astronomical discoveries got made, or how constellations got their names. You don't need serious equipment to make serious discoveries. Start with a simple question, and suddenly, you're somewhere you never expected to be. Your next discovery is waiting on TikTok. Learn more at tiktok.com/discovermore. At tiktok.com/discovermore.

• 12:09Speaker 01

  This episode is brought to you by Indeed. You're ready to level up your business, but the pressure to find the right person to make that happen is intense. Indeed-sponsored jobs can help carry the load. It boosts your job post to help it reach quality talent fast. Cut through the chaos with Indeed-sponsored jobs. Get a $75 sponsored job credit at indeed.com/podcast. Terms and conditions apply. Hiring now? Then this is a job for Indeed-sponsored jobs.

• 12:49Speaker 00

  Welcome back. As Nick was telling me, it seems like PN7 is an asteroid that has traveled in from elsewhere in the solar system and is now hanging out near us for a while. And asteroids like this can potentially help us learn about our solar system and its history. Because when it comes to learning about that history, here on Earth, we have this problem. Imagine that someone gives you some little colorful clay pots for your birthday, okay? You take the clay out, you roll it all together for some reason, so the colors are all mixed up, and then you fold the clay and you tear it apart and you re-roll the different parts and you bake them, maybe.

• 13:34Speaker 00

  And then for some reason, you decide to grind them all into dust and then you mix everything with water and you roll it out again. It's very difficult, right? To go from that final product back to your original little pots of clay. And that is basically what Earth rocks are like. Here on Earth, we have weathering and tectonic plates and all kinds of forces that fold and melt and blend our rocks into something very different from the original rock that they came from. So it's not always easy to figure out what our rocks were like when the planet first came together. If you go to asteroids, though...

• 14:18Speaker 02

  Asteroids and things that don't have atmospheres don't weather. There's no wind on asteroids, there's no rain, there's no plate tectonics, there's none of the things that produce all the rocks that we see on the surface of the Earth that look so familiar to us.

• 14:36Speaker 00

  On asteroids, there is radiation from space, but the rocks should be at least closer to the original pots of modeling clay. And that means that they are potentially amazing sources for the history of the solar system. Of course, asteroids also have a problem. They are very far away, which makes them hard to study. But every once in a while, the universe kind of throws us a bone in the form of a meteorite.

• 15:05Speaker 02

  These are chunks of material that start on the surface of an asteroid, make their way to the Earth in some way that we don't really understand, appear in the night sky or the daytime sky as a shooting star or a bright flash of light as that rock is passing through our atmosphere. And if that rock is big enough to survive that intense heating of being a shooting star, it can land on the ground and be picked up as a meteorite. These are some of the most valuable scientific time capsules that we can go out and put our hands on.

• 15:37Speaker 00

  Not even just time capsules, like space capsules also.

• 15:40Speaker 02

  They're space rocks, right? They're amazing. So meteorites are incredibly valuable, an incredibly valuable tool, because we can go and pick them up, study them in a laboratory in detailed ways that we would never be able to do with a rock that's out there in space that we're just studying remotely with a telescope. We think of that sort of process of meteorite delivery to the surface of the Earth as nature's version of a sample return mission. So we can send spacecraft out to go pick stuff up off the surface of an asteroid or a comet, hopefully, one day, and bring that back to Earth.

• 16:14Speaker 00

  But that costs like a billion dollars. A meteorite is like a free sample delivery, courtesy of the universe. And it means that Nick can go out and hold something from space if he wants to.

• 16:24Speaker 02

  You're holding these rocks, you're looking at it, and this thing is older than the Earth. Right? It's literally the oldest thing you can put your hands on. And it's like, that's just amazing, right?

• 16:35Speaker 00

  We've studied meteorites to learn about the history of the solar system and to try and understand how we got water on Earth. But they also have a problem, which is we don't have a ton of context for them. So there is a fair amount you can learn from studying a rock's makeup. But ideally, you want as much information as you can get about where it's been. With asteroids, we have a fair amount of information because we can use math to try and study their trajectory.

• 17:05Speaker 02

  We lose that context from the vast majority of meteorites, meaning we don't know where they came from in the solar system.

• 17:12Speaker 00

  So we have asteroids in space, which have lots of context, but we can't hold them in our hands and analyze them in detail. And we have meteorites, which we can analyze in detail, but which often have less context. Kind of feels like an O. Henry story. Except this is where quasi satellites might come in. They're still in space, so we can get some context on them. But they're also closer to us. So Nick says they're somewhat easier to examine.

• 17:45Speaker 02

  We can study these objects in detail as, you know, sort of case studies and say, okay, this is the kinds of things that are coming into the Earth-moon system. Let's understand what it looks like through a telescope and then compare that to the objects that are not just passing by or, you know, doing a few laps and then leaving, but instead compare it to the ones that actually hit the Earth and are recovered as meteorites. And if we can improve and establish meaningful linkages between what we see remotely with our telescopes in terms of asteroid properties and in the laboratory with meteorites, then we gain a much more holistic view of the solar system.

• 18:23Speaker 00

  There are also other reasons that it could be cool to gather more in-depth data about asteroids.

• 18:28Speaker 02

  There's a lot of talk right now about what's called in-situ resource utilization, ISRU, which really means just using the stuff in space to produce material that'll be valuable for spacecraft or human exploration.

• 18:43Speaker 00

  So the thinking is basically, what if asteroids could be like refueling stations as we go through space? Or just useful sources of material? It's a pretty far in the future kind of idea, but these little asteroidal quasi satellites could help us understand more about how realistic it might be.

• 19:04Speaker 02

  So that's the sort of exploration and resource utilization perspective on these objects.

• 19:10Speaker 00

  Maybe the most exciting next step would be if we could go examine something like a quasi satellite directly. We haven't known about them for all that long, actually. We found the first one back in the 2000s. And no one has gone out to take a sample of a mini moon or a quasi satellite directly yet. But there are a bunch of different organizations that have gone out to kind of take a look at a whole bunch of different near earth objects.

• 19:37Speaker 02

  NASA had a recent mission called Osiris Rex that went to a near earth object called Bennu. That object in particular was targeted because we think it's, we now know that it's water and organic rich. Osiris Rex touched down on the surface of Bennu, picked up some samples and brought them home. So we now have pieces of Bennu curated and brought back to earth. That's one example. There are others. The Japanese have launched a pair of just amazing missions called Hayabusa and Hayabusa 2, both sample return missions going to near earth objects and interacting with the surface and in both cases, bringing stuff home for us to study in the laboratory. The Chinese are getting involved in this

• 20:21Speaker 02

  as well and have a whole fleet of planned missions coming up. And actually, one of those is going to be targeting one of these quasi satellite kind of things. So we'll be able to get that particular target, we think is one of the lunar ejecta things. But we'll find out hopefully when the spacecraft gets there, you get up close imagery, get more detailed information, you can say hopefully with better certainty of whether or not this thing actually is a chunk of the moon. Does it look like the moon? Does it look like something else? So yeah, it's an exciting time to be sort of involved in this, this area of planetary exploration. It's a really rapidly evolving space.

• 21:05Speaker 00

  So, watch this space. And meanwhile, we'll probably continue to find cool objects floating around near us. And instead of talking about whether we should call them second moons, or quasi satellites, or whatever else, I would argue, we should talk about how cool it is that we have essentially tiny time capsules for neighbors. Just like little archives of our solar system that are out there to be explored.

• 21:49Speaker 00

  This episode was produced by me, Byrd Pinkerton. It was edited by Joanna Solotaroff, who also runs the show. Noam Hassenfeld made the music. Christian Ayala did the sound design and the mixing on this episode. Melissa Hirsch checked our facts. Thank you, Melissa. And Jorge Just, Meredith Hoddinott, Julia Longoria, Sally Helm, and Amy Padula are even better than the very best QVC clip. Thank you to Brian Resnick, always, always, for co-creating the show with me and with Noam. And thanks to Tracy Becker at the Southwest Research Institute in San Antonio, Texas,

• 22:29Speaker 00

  and to David Drilling at Northern Arizona University in beautiful Flagstaff, Arizona. I appreciate both of you for taking the time to help me make sense of the universe. If you have thoughts on this episode or questions, please write in. We are at [email protected]. And I would love to know, for example, if you have dreams about the moon or if you have ever turned into a werewolf. If you want to support the show and help us keep making it, please join our membership program. It is at vox.com/members. You get ad-free podcasts, unlimited access to Vox journalism. And if you tell our bosses that you signed up because you love Unexplainable, you'd be doing us a big solid.

• 23:12Speaker 00

  You can also do us a big solid by leaving a nice rating or a review or just by telling people in your life to listen. Unexplainable is part of the Vox Media Podcast Network. And we will be back in your feed very soon.

• 23:36Speaker 06

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