The Supermassive Podcast - The Kuiper Belt...Revisited

Episode Date: September 3, 2026

Yes, it’s a welcome return for the giant doughnut at the edge of the solar system filled with lumpy space potatoes. Dr Becky and Izzie are joined by Meg Schwamb from Queen’s University to discuss all things Kuiper Belt, the New Horizons mission, Rubin telescope and mysterious planet 9. For ad-free listening, join The Supermassive Club on Supporting Cast. Every paying member helps keep the show running, so thank you! Send us your astronomy attempts, questions (and nonsense!) to [e-mail], on Instagram at @supermassivepod or post in The Supermassive Club. The Supermassive Podcast is a Boffin Media production for the Royal Astronomical Society. The producers are Izzie Clarke and Richard Hollingham.  Hosted on Acast. See acast.com/privacy for more information.

Because they're small bodies, they get kicked around by anything more massive. The lumpy potato rocks of space are like to call them, right? I'm going to be effusive about my love and how terrified I am of the Vera reboot observatory. Becky, do you actually think there's a planet? Hello, welcome to the Supermassive podcast from the Royal Astronomical Society, with me, science journalist Izzy Clark and astrophysicist Dr. Becky Smytherst. It has been 20 years, is, since Pluto was demoted. to a dwarf planet. Now we say demoted, I feel like he was promoted, because he went from the

smallest of the planets to the king of the dwarves. But Pluto became a dwarf planet, but anyway, but this time we're going to go back to the edges of the solar system to explore a region called the Kuiper Belt. That's where you find Pluto and some of the other dwarf planets. Can you believe that we first covered this in 2021? And that was five years ago. I felt like that was so recent. And I don't understand what's happening. Yeah, shout out to. the listeners there are Torres who inspired us to revisit this topic because apparently five years is our grace period. Yeah, we always just come back after five years and we're like, what have people figured out since the last time we covered this topic? What's been happening? Yay. Science.

If you listen to our last bonus episode, you'll know that Robert is taking some time off to recover from surgery. I've had an update. He's out of hospital, which is great. He managed to get out just in time to see the eclipse. Yay. So, hooray, we were all worried for him. But thank you to everyone who sent him well wishes. He is on the men slowly, but surely. But he's never missed an episode.

Right. Yeah, that's crazy. I know. So while he's off, Becky is stepping into his shoes. That doesn't mean that she's suddenly the deputy director of the Royal Astronomical Society. I was like, oh my email inbox is not ready for this. Yeah. So what are your thoughts on, Becky?

God. I'm prepared for this job. You know when you have those nightmares where you wake up and people are expecting you to do something? You're like, you must have an opinion on everything to do with astronomy in the UK. Go. No, Robert is very much more prepared for that than I am.

But I think I can do Robert's job on the podcast. Yes. Just about. We'll start you off easy then, Becky. So what is the Kuiper Belt and where is it? Yeah. So the Kuiper Belt is like another asteroid belt, but it's on the edges of the solar system.

So it's lots of rubble that's been left over from the formation of the solar system, the formation of the planet. So you've got hundreds of thousands of icy asteroids, comets, and dwarf planets. The lumpy potato rocks of space, as I like to call them, right? It starts just past Neptune's orbit, so around about 30 times further away than the Earth is from the sun, and it extends to about 50 times the Earth's sun distance.

Now it is, I am guessing here that you are picking up. picturing a very flat disk of rubble. Yeah, I mean, I won't lie. It's kind of Space Wars-esque. Yeah, sure. Space Wars, Star Wars-esque. Yeah, okay, that makes more sense. I was like, space.

The budget version of Star Wars. Yeah. So I'm picturing, I think everyone's picturing very, very flat in the same way that the solar system, you know, very flat plane or the planets orbiting in the same plane. But actually, let me change in that view in your head that you've got right now, and you can start picturing it more like a big fat donut, right? It is thick and it is puffed. up. Okay.

Yeah. So there's a lot more sort of chaos and not as sort of order of rotation in the Kuiper belt. It's named after Gerard Kuiper, who was the first to speculate about the existence of planets and objects beyond Pluto in a paper in 1951. You'll often hear people

refer to those objects as trans-Neptunian objects, T-N-O's. Just because I think there are a lot of blurred lines between dwarf planet asteroid and comet, right? So it's better to just have like a one word or one sort of phrase that just clumps them all together. We know of around 2,000 TNOs, Pluto being the biggest, but it's estimated that, you know,

there must be millions of smaller objects out there, all of which, you know, might have clumped together billions of years ago to form a planet around 10% of the mass of Earth, except for the fact that Neptune formed and disrupted everything and gave stuff too much. energy and it's ended up in this big puffed up donut of the Kuiper belt. Okay. And there's also something I want to say here that sometimes I will switch between Kuiper and Kuiper and that. Okay.

And it's the same space. It's a safe space to do that. Yeah, sure. I'm sure somebody who, I can't remember, is Jericho, Dutch? I'm sure someone in the comments will tell us that we are pronouncing it wrong because that is usually what happens when I try and pronounce things. but yeah but it's okay because our next guest also says kuiper so you know it's okay i think it's a british-american thing i think it's kiper in british and kuiper in american okay so maybe i'm saying it

wrong either way we've not wrong but you know they're not right for my accent i don't know i think it's because there's such a there's such a massive like variation in accents in academia so you pick up weird things from people who, you know, like you've learned stuff from who have that accent. So, yeah, who knows. Anyway, people can go with what they feel like. Yeah. So we've covered that starting point of where the Kuiper Belt is, but what can it tell us about our solar system's history and any other potential mysteries of the solar system?

So you might remember Dr. Meg Schwarm, who was a previous guest on the show. She's a planetary astronomer at Queen's University, Belfast and studies small bodies in the solar system. I think it tells us a lot about our own history in two ways. It's kind of like going to an ancient dig, right, and looking at some Roman artifacts, right? Like, whatever you hear about, you know, a new basement or a new house being built in England and then, oh, wait, there's these Roman era like artifacts found, right? We learned something about the history, right? And so of the area. And it's something similar for the solar system of like, these small objects didn't quite form into a planet, but they're the building blocks. And so by studying them because they're still around, we get to see what was sort of fundamentally put into the core of the giant planets. It's like thinking about a house. The walls are sealed, right?

And you don't see the plumbing and you don't see the electrical wires. You don't see the wood that's bracing everything, right? And the stone, you sort of you see the finished product. And this lets us see those bits around. And so I like to think of it as like going to the skip outside of a house being built and just going through what's left and you kind of know what was in the house. So that's how I like to think of the Kipelot, is that we get to sort of go and look back at what the history of how things assembled in the solar system. And then the extra cool thing here is that because they're small bodies, they get kicked around by anything more massive. And so their orbits give us a history themselves of other things that we didn't know about in the history of the solar system like Neptune and the giant planets actually moving from the original orbits.

Well, yeah, I mean, this is a crazy thing, right? So let's talk about that a bit more. That rubble, what does the solar system skip tell us? Well, it tells us that like now thinking of the context of like interstellar objects, right? So we know of three that have come in. Planet households formed around planetarium around other solar systems and coming in, right? And they sort of feel the effects of the sun and we see them fall in and they leave the solar system. They kind of look for, I mean, on average, kind of like the stuff we see in our own solar system.

And so by studying Khyberwood objects, we kind of see they look similar. Let's talk about some of the sort of bigger objects that we see out in the Kuiper Belt. Pluto was demoted to a dwarf planet, or renamed as a dwarf planet. But what else is out there? It came home, right? It's like 10 objects that are similar size, slightly smaller. It came home. I think we have a really a better understanding, I think, of.

how Pluto fits in with the rest of the sort of dwarf planets, a large, cypid objects, that they're that last stage before you'd start forming the core of a giant planet. And so I think one, because we've just had more time in observations, the fact that the JWST telescope is now live, it's really a game changer because it can see signatures of ices that are just very hard to see in the near infrared and optical. That's really exciting is that we sort of can put Pluto in a better place with the rest of these objects. Still though, those dwarf planets are kind of still special because they're that mid-stage between forming cores of giant planets and the rest of the Kuiper-Vo.

Yeah, so can you tell me about some of the other dwarf planets that are out in this region of space that don't get as much limelight as Pluto? I think maki-make, or if you read it, it's make-make, but it's maki-make, it's the correct pronunciation. It's really cool right now because with J-WST, there was a detection of basically it looks like a volatile gas, right? There was some type of outgassing event. So like a temporary atmosphere, like kind of like a puff of gas, some ice sublimated, right? And so it's not like enough to be a full atmosphere, but enough to be like a gas per puff, a plume that could be detected. And so that's telling us something, like, is there, you know, whether that happens frequently

on maki, maki, or this is just something new that we haven't observed on the other objects because of their compositions. So maki-make is kind of a bit of a mystery. It has a lot less nitrogen than Pluto. And so that means a lot more of its vodels can evolve into like organic gunk. And so maybe this is part of that process. We're not 100% sure. But I think that means that Pluto is not just the coolest one now. We're all looking, scratching our heads at Makamake-Make going, what's going on there? Yeah. And I mean, hey, maybe this is quite an ignorant approach from me, but, you know, I sort of think of the Kaipa-Bel region, cause it so far and cause it so cold of just being kind of icy rocks and not much really happening there.

But if stuff like that, if, you know, if you do see outgassing events like that, that's, I'm wrong, basically. It's not the case. An interesting thing is it's not so surprising because there are comets that are active well in the Kuiperveld region that we see. And so there's only a handful of

them, but they're active. And so something's driving it. We think it might be carbon dioxide or carbon monoxide. Those things are volatile at those level areas. But one thing is we've never seen lots of Kuiperbent objects act like comets. But

Like, nobody thought that the Khyberbote would maybe be, even the large ones would maybe be as active as might be given this new result from JWST. And so it is one of those puzzling things that we're now like, hmm, maybe we want to take a look again to see if maybe there is an active Khybera object. And related to that, a recent study that used occultations, right? So they're using this trick of watch the Khyberan object go in front of a star and blink out the light. So you can get basically a really cool and accurate estimate of the shape.

of the size of the object from the time the star blinks out to when it comes back, they've detected a tiny carpet object with an atmosphere. It's a really tiny, not likely to survive atmosphere. The thought is that maybe this one got hit, and that's what's caused this atmosphere to create to be there because it can't survive the age of the solar system. But yeah, they just got super lucky. So the thought is probably a collision,

but still, like maybe there's more activity in the Kiper Belt that we weren't really aware of because we just can't detect it with optical telescopes. That's incredible. I mean, we talk about this quite a lot on the show of just like some of astronomy is really just being right place, right time. Yeah. To be able to see these things.

But it just makes me think of all of the other possible mysteries out there. So just how many objects does the Khyper Belt tell us about the rest of our solar system? Because you teased it earlier on, but there's a big old, sort of mystery wrapped up in there, isn't it? There's tons of mysteries. This is just a question of which one you want to talk about. I mean, one is just that the giant planets themselves moved. And so the history of that and the influence from Neptune moving about 10AU outward,

while the other giant planets moved inward. Plus, we think one that got kicked out. So we think the best fit to the orbits for the chiberode objects today is that there was another planet like Neptune. and it got kicked out by Saturn as everybody was rearranging. And so as these giant planets were moving, right, they scattered, right, the planetes metals. And so the Kuiper Belt has a component, we think, formed in place. We call them the Kui-Klasicles. And then everybody else in, we think within the Kuiper boat got in placed while Neptune

was moving outward. And so we can see that history. We can actually run in our computer, right, a dynamical model and put like tiny test masses in and run the simulation just using gravity. and you can get and reproduce the orbits of what we see in the Kuiperville today. And so what that may tell us exactly about how the conditions were in the early solar system, I think, may change a little bit as we get into those really fine details. But also, right, I can't tell you how many planets are in the solar system, which I hate.

Not because of Pluto, right? Everyone's like Pluto, and I was like, no. No, actually, surprise. Or series, because series used to be a planet too. We don't fully know whether there's a planet, another planet, way beyond the Kuiper boat. And so there's some hints that very distant objects might be influenced by a giant massive objects, which likely would be a planet on an eccentric orbit, a kind of stretched circle shape, doing like the sheeped dog thing of hurting sheep into a pen. And we see all these objects with sort of these similarly aligned orbits.

There's a big debate, I would say, of whether that is, I see that kind of. because that's where I pointed my telescope versus I see that because it's a real signal. There's still this debate within the field of astronomers, which one of those is right? And so if it's right, then we have another planet that we can't see. That's kind of exciting, although I scratched my head a lot because it's trying to figure out that signal, I think, means we need more discoveries out well beyond Neptune to answer that question. The idea that there's this planet nine just blows my mind and I've never wanted people.

to discover something more. So it's just like new area of space unlocked, like let's go kind of video game styley. It is great. It's one of those things that's just been, I feel like it's like a hundred years astronomy mystery. Like there must be something. Oh, no, it's not that one.

Oh, we thought of about it. Oh, no, we've not. And now people are like, come on. Come on. So we will actually be hearing from Meg later on in the show about the missions that are exploring the Kuiper Belt. but Becky, do you actually think there's a Planet Nine? Please say yes.

I mean, we have got a full episode about Planet Nine, right, where we just were so excited about it. You know, I'm sure I will link it in an episode description below. And actually we spoke to Mike Brown, who is the person behind sort of getting Pluto reclassified, let's say. Yeah, I like that, yeah, that's better, yeah, that's a better word. Yeah, I think, to my honest, the Planet Nine explanation, I think it looks like the most likely explanation currently with the evidence I say that that we do have,

even though we don't have evidence for the planet existing yet. We've had surveys looking for it for decades, but none with like the chops to really be sure that it's there, you know, none with like the actual like the coverage and be able to go like deep enough to see faint things at that kind of distance. I think the Rubin observatory is really going to fill that gap though. So Rubin is just come up. online doing its survey. It's in a telescope in Chile that's been built to do an, well, to take an image of the sky every three days for 10 years, which is crazy. So obviously by doing that,

it spot things that move or change and flare in their brightness, but also by coming back every three days, it adds every previous picture that it's taken together. So you sort of get a deeper image each time as well, so you can spot really, really faint things. But like I said, also things that move like things in the Kuipa belt. So if Rubin doesn't find Planet 9, then I feel like then I'll be more convinced that it doesn't exist. Yeah, okay. And the field might start to move on to other explanations, whether that is like disc instabilities

causing these weird orbits and maybe start taking that primordial black hole hypothesis, more seriously, the one that I love that we talked about on the other podcast. I won't, I won't explain that here. You have to go listen to the other one to find out what that's about. What a tease. But also in a moment we'll hear from Meg about why she's excited for Ruben as well. So I think in general, everyone, it's just like Rubin. Yeah, I think the entire astronomy community right now is like Rubin or Roman or both.

Roman launching at the end of August. So very excited for that too. Another survey telescope with this one in space. Also, Euclid, we've got to give a shout out to Euclid. There's just so many like big survey telescopes just doing the best work at the minute that, yeah, we're all very excited for. Yeah, it's great, isn't it? So can we talk about some of the other bizarre objects in the Kuiper belt? What's out there?

Okay, well, you've got ERIS, which is like the next biggest dwarf planet after Pluto. That's technically part of what's known as the Scattered Disc, not the donut of the Kuiper Belt, even though the scattered disc is kind of classes the Kuiper Belt. There's still two separate components of it. So that is a much thinner disk of stuff that goes out to be on like 100 times the Earth's sun distance. So ERIS being out that far is kind of cool Because it's It's not tiny

It's I mean it is if we compare it to like the Earth or Pluto Right it's only 67% of the moon's mass So it's smaller than our moon But it is technically the largest body of the solar system Not visited by a spacecraft Okay And its orbit is really eccentric So instead of like close to being a circle

Because none of the planets orbits are perfect circles Because that is a very very special case It's more like you'd get something that's just off a circle. But this thing is like the most oval of the ovals. So it comes in as close as 38 times the Earth's sun distance. So getting in towards Neptune, but then goes out to almost 100 times the Earth's sun distance on its orbit. It takes 558 years to make one loop.

And if you actually see a diagram of its orbit and compared to the rest of the solar system, it is honestly bizarre because you've got like the flat disk of the solar system Pluto's on this like slight angle and then ERIS is like 45 degrees out compared to the rest of the things so it just looks really weird and there's lots of ideas to be like

well maybe it's a captured planet or something you know maybe it didn't really form or maybe something has like scattered it out you know really far into this sort of scattered disc so yeah it's just really cool to think of why ERIS where ERIS came from

and that's why it would be really cool to send a spacecraft to it if we could and again is the current leading sort of idea that there's this like other planet or sort of the movement of the gas giants? Is that what we think's disrupted that for ERIS to be like such a bizarre plane? Yeah, it could be, it could be that. I think to be that bizarre, it kind of maybe has to be captured. I don't know, but maybe the planet experts would know more than me, whether it's actually possible. I'm sure anything is possible if you throw enough

interactions in there. But yeah, I think it's a really, really, really weird one. Also, how Maya has caused a lot of controversy as well over the years because of its shape. So it's classed as a dwarf planet, but it's not round. It's like really elongated like a potato. More lumpy space potatoes. Yeah, which is really common for asteroids, but not dwarf planets. Because to be classed as a planet or a dwarf planet, like this is where we have these blurred lines, right? But it has to be dense enough for something called hydrostatic equilibrium to come into place.

So this is where it has to be heavy enough for gravity to shape everything smooth instead of just like, you know, clumps of jaggedy rock or clumped together. Now when that happens, usually gravity ends up shaping it so that it is a sphere so that basically it means that gravity is roughly equal across the entire surface.

And that's kind of what it means to be in hydrostatic equilibrium. Halmea is smooth, but it's like a rounded rugby ball shape instead. So you can imagine how different gravity is on, you know, sort of like one end of the rugby ball compared to like the short end of the rugby ball. So it's really strange. But it's also spinning really, really fast, right? So this could be the explanation for its shape. You know how we say that like Earth and Saturnities are blates, ferroids because they're spinning so they're the middle's bulge out. So it's interesting

to think whether actually because of that and then also because a lot of other TNOs, these trans neptuian objects share like its other properties like orbit and things like this. they're all thought to be part of what's known as a collisional family. So like broken pieces of a bigger object that were destroyed basically in a massive collision. And how may I might have retained sort of the energy that gained in that collision. And that's what sets it spinning so crazily and led to this like really weird shape. Yeah, that's what I was going to ask is like, is it because it's spinning that it's kind of ended up in that shape?

Or does that shape come first and that's what keeps it spinning? possibly the it's a little bit of a combination of the collision produced some weird shape pieces and then the collision also gave it the spin and then hydrostatic likearabermines rounded it as much as it can whilst also spinning so a little bit of big chaos energy okay yeah yeah um and uh sarah who recommended that we do this uh topic wanted to know if dwarf planets are still growing in mass from gravity No, not really. I mean, like maybe a few grains of dusty, you know, but not like significant. No, no. Otherwise space is just really empty, right? And most things now are on stable orbits around the sun.

So they're unlikely to encounter like another object to, you know, collide or create and grow in that way that we think they did in the early solar system. Right. Growth relies on unstable objects and a really dense. disc of smaller objects that can have lots of collisions to stick together and that material that can pull in under gravity so that collisions can make bits lose energy and fall towards other heavier objects and things like this. And also, like, what we think happen in the early solar system is that a lot of those unstable objects were ejected through those interactions as well and only left with the smaller objects that then, you know, clumped together and reach this critical mass. That means that, you know,

space is really empty and collisions are just really, you know, unlikely now in that space, which means that the dwarf planets are probably as, as heavy as they're going to get. Okay. Much of our recent knowledge of the Kuiper Belt comes from NASA's New Horizon spacecraft, launched some 20 years ago. Wow. Yeah, I know. I'm like, what?

Okay. In 2015, it sent back spectacular close-up images of Pluto, and it's been exploring the far-reaches of the solar system ever since. So we're going to hear again from Meg Schwarm about its recent discoveries, but first, she wanted to tell me about how the Earth-based Vera Rubin Observatory in Chile is playing its part

in observations of the Kuiper Belt as well. I'm going to be effusive about my love and how terrified I am of the Vera Rubin Observatory. Don't worry, you're in a very safe space to do that. We do it all the time. Because it's amazing. It's equipped with the largest field of view

digital camera ever built. It covers 45 times the size of the full moon and a single exposure and a single pointing of the camera. And it can take exposure in 30 seconds and then quickly move on to the next part of the sky. And so Rubin Observatory's telescope is faster than most human beings. And so if you were in the dome and it was going to the other side, you can't outrun it. It will hit you. So we're getting a movie of the night sky and how things change in our brightness, how they move, which I care about for solar system objects. Again, how their colors change. Like, we're going to find more asteroids than have been ever found in human history up to the state with the survey.

So, like, just think of all the asteroids that have been found. Everybody including, like, Gallo, et cetera, all the way back from today, the Rubin Observatory is going to find more asteroids than we've ever discovered. It's going to find 37,000 new outer solar system objects. So we're going to get really into the detail of how Neptune migrated. Now, yeah, yeah, finding lots of objects is exciting. But what's really hard is that when we do a survey, if we go to find moving objects, or we're taking a picture of the sky, we're coming back later, taking another picture, right, and looking for the things that have moved.

Nobody ever gives us time to follow that up. And so because Rubin is such a big field of view, and it's observing the same sky over and over and over again for 10 years, we get to follow them. up and then get their colors. So we get to see them, right? It's like going from black and white TV to tectacolor, right? Such a different view of the world, right? And so we get to see that for all of those objects,

the 38,000 objects that Rubin is expected to discover in the outer solar system. And now we get to take that picture of how did Neptune move and put full composition into that. It's amazing. Where do we even begin? When will you be able to have that data and start looking at that? we've already can and that's the exciting bit is that because the telescope was being commissioned last year they did a commissioning survey and so some of those observations are already been processed and

released i was spending part of my summer sifting through some of that data we've got the appetizer and so now when the survey is fully running for many months we're going to find you know a lot of we'll get so much more yeah you're ready for the main course okay yeah i want to also talk about New Horizons as well. This is a mission that's launched in 2006 and has been able to track and observe Kuiper Belt objects. So tell us about that mission. What has been its aim and what has it seen? Well, New Horizons is a NASA spacecraft that was launched, sent to basically fly by Pluto and give us our best view of the store planet. The Khyper boat had not been explored. And so New Horizons has started to do that. So it flew past Pluto. It had blew

our minds, I think, and collectively everyone's seen probably the heart at this point on Pluto, right, and showed us things about the surface and how it's such an active world. Then, you know, Pluto really faded in the background, the sense that New Horizons couldn't orbit, Pluto, didn't have enough fuel to do it. So it could only fly by, but the mission was lucky enough to find another hyperb object to go to, which was Erikaop, which is very different from Pluto. It's a tiny,

col-classical, one of its objects that was formed in place where it is in the solar system. And so, it gave us, I think, a really different view of plan information just from being able to look at those images up close and all the data coming from the spacecraft of its spectroscopy,

looking at composition, right, looking at how the object rotated its shape, just even from the images. right compared to Pluto. And then it's been sitting, you know, continuing on through the Kuiper Belt, doing more monitoring because there isn't another right now, fly by target for it to go to.

So it's been watching other Kuipera objects from its vantage point in the Kuiper Belt as it continues to move out of the solar system, looking at how their brightness has changed as you change the viewing angle from the sun, the object, and New Horizons. How important has New Horizons been for your field? of work? I think it's really been important as sort of that bridge, right? Because everything I do

is what you would call remote sensing. I use telescopes to say them, but I'm using things at Earth. They all look like point sources, stars to me. I don't get to see their shapes. I don't get to see really the distribution of substances on their surfaces, right? I get an average estimate. And so New Horizons let us zoom in. And so I think that's really exciting is that we can sort of start understanding how wrong or right we were in thinking about our theories about what does that then mean for other objects like ERIS that we're looking at that don't have a fly-by mission. Yeah, okay. And so what has it seen in the last, let's say, five years? What have been some of the more newer discoveries or data that we've seen from the mission? Yeah, and some of it is really just a reanalysis of what's

been there. And so I think that's really exciting is that, you know, recently that the glacial heart rate that's on Pluto, it's leaking liquid nitrogen. And that's been sort of, again, through analysis of New Horizons data. That data sets so rich that even this result came out not that long ago, that, you know, this is recent in the last few weeks, months, but it's also staring at these other objects looking at how their brightnesses changes as their viewing angle changes. And that's exciting because we can't access that sort of orientation from Earth. And that gives us also an estimate about composition in a way about the size of ice grains and things like that that can tell us how those ice is formed and in what conditions. And so that's the exciting bit as New Horizons

is sort of doing that detective work. Well, also just counting the dust up. How many dust particles are there, which tells you how much stuff might be there, which again, is kind of important thinking about whether there's a buildup to possibly another belt beyond Neptune and beyond the Kuiper belt or Planet 9 if it's there. What is the plan for New Horizons? Is it that it's just going to keep going or is it in the orbit? Like what's that trajectory and how has it been able to be there for so long? It is on its way out, never to be seen again. Like the Voyager spacecraft, it will eventually hit into interstellar space. And so it's going into a hibernation mode and then waking up and doing some measurements with its dust counter and its imager, and then going back to sleep. To preserve fuel,

also just to preserve people's energy as well, right, and make sure the spacecraft stays healthy because there's lots of radiation as well as you go further from the sun. There's active searches to look for an additional flyby target, but it's moving, you know, I think about 200 a u away. The number of type of objects has dramatically dropped. And so the team is searching for another flyby target to go to, but the probability drops every year. And so I know there's efforts. There have been published results of looking for flyby targets and they haven't found something yet to go to. They can observe objects. And so they're going to continue to do that, but they don't get close enough that they can actually do another type of flyby that was done for Aracoth and Pluto. So who knows?

It could be that they find something next year. Could be that, you know, using combinations of new telescopes, there's been proposals of how you could use the Ruben Observatory to look for a potential new horizons target by staring at the same patch of sky. It's kind of a wait and see. It seems like it's probably not likely, but there's still a small chance they might find something. And so you got to go look, right, when there's still a chance. Thank you so much to Meg Schwarm from Queen's University.

So, okay, let's dive into some listener questions. Yeah, I've got them all this week. I don't get a break while Robert takes one. You've got to earn it this month. So Freya 50 asks, what's the difference between a Kuiper Belt object and a comet? A very pedantic definition. So side note, I think we first thought that all comets came from the Kuiper Belt, but then we realized that most actually come from that scattered disk that I was talking about before

to get those really extended orbits that take it way far out from the sun and then back in really close again. but comets specifically are defined by like what happens when they get close to the sun the fact that you get this sort of icy material boiling off that takes a load of surface rubble with it and you get this big tail of gas and dust trailing out behind it that look beautiful and amazing in the sky and they're defined by that and by their really eccentric oval-shaped orbits that bring them really close into the solar system so then transeptune objects could be, you know, very like comets in their makeup and the fact that they are these icy,

you know, balls of lumpy rock, you know, but their orbits aren't as eccentric. They don't come as close into the sun. So you don't get the cometry tails actually forming. But there's nothing to say that, you know, if you knock an icy Kuiper belt object off its orbit so that it does end up coming closer into the sun, it wouldn't become a comet, you know. So it's just, that's where I was like it's a very pedantic definition. I see what you mean there. Yeah. Okay. And then Lauder on Instagram asks, is it possible to know the exact extent

of the Kuiper Belt? That is a good question. And it's one people who've studied for years. So there is something known as the the Kuiper Cliff. So it's like a massive drop-off in the number of objects that you do get around 50 times the Earth's sun distance. It's why picturing it as like a donut is like something that I encourage because it is quite a cliff. And it's, the reason that it's around 50 times at Earth's on distance is it's

one of these resonance points where stuff takes twice as long to orbit the sun as Neptune does. So you could argue that it's, it's there and it's a real drop-off because of that resonance. Or there's people that have argued that it's actually a bias in our observations, that our telescopes just aren't sensitive enough to pick up objects beyond that point, right? Is it perhaps because there are a lot of, they get, that objects get small. smaller beyond that point, right? So we can't see them as easily. Okay. There's lots of confusion though, because that's not what you'd predict in models of solar system formation in terms of how much material you'd need to form planets as big as Uranus and Neptune and Pluto at that distance

from the sun. You'd actually need a really big increase in the number of objects at that distance to form those planets that we see. Of course, those objects could have been ejected in the past because of all the chaos going on. So there's going to be a little bit of, a lot of work going in to trying to prove whether that is an observational bias, this quip the cliff or whether it is actually real. And again, I think Rubin is going to help answer that question, probably raise about 20 odd more about the quiver cliff if it is there or not. But hopefully, Ruben will put that one to bed, whether it's biased or whether it's real. Rubin's just going to help us keep this podcast going as well. We're just like, there's new things.

You know, I get asked this question all the time. People like, how do you come up with ideas for videos all the time? How do you come up with ideas for the podcast? I'm like, well, people keep publishing papers and I don't know what to tell you there's just more science going on all the time. Space is very old but we're still, we're just very new to it. 14 million years worth of stuff to talk about. And Benji wants to know how would new horizons identify a new target? And I guess... Oh, right. If you're going to pick a new one.

Yeah. And I guess I wonder, you know, it kind of goes back to what Meg were saying. And if you're saying it kind of the number falls off a cliff as well, it's probably quite hard to do that, right? Yeah, I mean, it's hard to pick a good target because you have, you're going to have to pick one that wouldn't take too much fuel to change the current trajectory of New Horizons, ideally. Ideally, you'd pick one, though, that was also based on, like, scientific return, ideally, like how much you were going to learn from it. But we also know very little about objects at that distance, as we saw with the surprise with Arrow Cough that got picked, right? Like, it was just thought, okay, well, that's one that we don't use up to. much fuel and we'll just figure out what we find when we get there. And then it turned out to be that like snowman shape.

And we learned so much about how stuff sticks together and that it's not like a violent collision. It might be more gentle and things like that. So it's hard to base it on scientific merit. And that's why people tend to decide based on the amount of fuel it's going to take and think most about like the longevity of the mission. So Arakoth was selected because it only required like 35% of the remaining fuel that New Horizons had at the time.

So ideally you'd pick something where you can leave some fuel left because you never know you might want to pick something again in the future, right? So I think it's a hard decision for the New Horizons team because, you know, there could be something that they could spend all the fuel on to go to one specific object if that's going to be the best thing to go to or leave something for an object that might be discovered in the future by Rubin, you know, that we might learn something from. Okay. Yeah, it's got enough fuel and power so that it could operate into the 2040s.

So I definitely think this is going to be something that everyone's weighing up. And so maybe Rubin will sweep in and save the day and find something that would, you know, well, even give us a load of potential new targets to choose from that don't spend as much fuel. But again, we'll just have to wait and see. Yeah, because I was going to say, like, it will be quite fun if you're in charge of that mission just to be like, do you know what? Let's take a risk. Let's go over there.

But actually, you've got so much to wait. It's not that simple, is it? You can't just be like, well, let's just see what we can find. Yeah, and it's not a hop, skip and a jump pad that you've got to remember, like, the distances involved in this are ridiculous, right? So, you know, it's currently through empty, people are like, you can't just leave it going in a line and it will just fly past stuff? No, it would, it's just going to be empty space unless we actually give it some, a nudge to send it towards something. Yeah. And Orjan Jimmy asks, why can't we see the belts like our Kuiper belt on other stars?

We observe a lot of stars, right? we can or at least I mean we can't see individual objects because they're tiny and you know we struggle to detect

even Earth size ex upon us with like current detection methods around stars but we can see like an overall infrared glow of like the heat that's left over from the formation of a

coipa belt the formation of a sort of exo solar system in general or just like the heat from collisions that are ongoing in something like a coipel around another star

exo cuiper belt usually what that means though is that we spot the brightest ones, so the ones that are still very warm from formation around much younger stars. Yeah, okay. And they're known as both exo-cooper belts, but also just debris discs is what they tend to be called because exo-copy belts are a bit of mouthful. Because you're literally looking though at like the leftover debris or rubble from star formation that, you know, might go on to form another planet in the future. The Alma array is like really good at detecting

these. Like, so you can search for the images if you want to see. some exo coiper belts but i mean i warn you like with many things in astronomy to the human eye it does just look a little bit like a blob a lovely little smudge that you're like well the size of that and the amount of heat coming from it that's an exo coiper belt and you're like is it what am i squinting we are yeah and i guess though does that mean like because i imagine you know temperatures at the coiper belt are going to be really low it's so far out from our sun so is is there are a possibility that there are some that are further out, but like we just can't see them because it's too cold? I mean, cold is relative. So everything will still have some sort of

infrared glow. I mean, a lot of like distant, quite about objects have been discovered in the infrared as well because of that reason. It's almost easier to spot them that instead of like the reflected sunlight, invisible light off them. Obviously it's possible that there's stuff that we aren't seeing with our telescopes, you know, like there aren't, you know, the edge of these debris discs that we see obviously fade off and there could be much more that we're not detecting. But in terms of like knowing whether they're there, we know that they're around younger stars. We know that they're around our older stars. So it's kind of like one of those inference things that you, it's like before we discovered exoplanets, like before we found the first one,

the assumption was always there that other stars must have planets as well. I don't think we have a telescope coming online anytime soon that could resolve anything like the scattered disk, you know, in our solar system or anything like that. But never say never, you know. Who knows? Okay, thanks. And thank you to anyone who is sent in a question. Keep sending them in. We love reading them.

You can email podcast at rass.ac.uk. Comment on YouTube. Find us on Instagram at SupermassivePod or for ad-free members. Then you can post on the Supermassive Club. Yeah. Comment on YouTube. I like that we've added.

Yeah. You can watch the podcast on YouTube now. So you can see how much we're absolutely sweating in the UK heat mavers we record this. Also, like, right towards the end of the episode that we're saying this, just to be like, don't watch us be really warm. Yeah, where me and Izzy are both just sat here, like, with our arms out, like in captives, just fully just like,

off screen. Okay, Becky, are you ready? Oh, yeah, they're not tired of me still. Usually we've got Robert to break up the endless Becky chat, but yeah. So let's do some stargazing. What should we look out for in September? Yeah, do you know, I think September's my favorite. favourite stargazing month. You've got the equinox, so you've got days, roughly the same

length as nights around this time. But it's still fairly mild at the end of, she's hoping it'll still be fairly mild at the end of summer. Please. I don't want it to be 38 degrees again. But anyway, hopefully it'll be fairly mild by September. And, you know, you've still got a fairly good view of the denser part of the Milky Way from the UK, you know, for the to the equator, then you'll still have that hanging around as well. Plus, I also love, like, catching the return of Orion in the early morning sky before dawn. Like sometimes that, you know, I'm up early enough, especially with the sunrise is getting later and later towards the equinox as well.

So I get to see it and I go, oh, my, hi, friend. I haven't seen you in ages. But yeah, speaking of being up early, if you are up early this month, then Jupiter's coming back to our early morning skies as we go through the rest of August into September. It's one of the brightest things in the night sky after the moon, right? So you should be able to spot it fairly easily, she says, in the east and towards the glow of the sunrise. But if you can't, my beloved toadale moon will swing past it on the 8th and 9th of September

in the early morning. So if you look out around 5 or 6 a.m. But if you don't want to be up that early, I don't blame you as if you don't. Try looking out for Saturn. Instead, it rises around 10pm in the UK at the minute. And it's around most of the night with its sort of yellowish tinge. But again, if you need a nice handy moon signpost, that will sweep past on the 30th of August to be like the bright thing next to the moon is Saturn. Given that the sky is getting darker at respectable times again, you know, you can have your tea and then nip outside rather having you tea and then waiting around and then be like, I have to delay my bedtime. It does become more accessible for people to do a bit of astrophotography. So I figured, you know,

Robert usually gives people some deep sky objects to look out for. So I thought I would do the same. Love that. If you are feeling a bit rusty after the summer, obviously try andromeda again first. If you're looking for an easy one to just ease yourself into, especially for the northern hemisphere, it's going to be higher up. It's going to be there. but also nearby it is M33, the Triangulum Galaxy, if you want a little bit more of a challenge this month. See if you can capture it and send us some pictures in the usual formats. Supermassive Club, I'm sure we'd love to see that.

Because just both of them are coming into really excellent positions in the sky in the late evening as we get into September. So send all those picks to the Supermassive mailbox or post them on the forum. Everything from beginner iPhone shots to first deep sky objects attempts to, I can do this in my sleep, I'm a pro. It will be received with great joy. And then please teach me how to become a pro. Thank you so much.

So we'll be back with the Q&A in a few weeks' time. That's the bonus, right? Not the full episode, isn't we? Just a Q&A, right? Yeah, yeah, yeah. Just a bonus Q&A. A bonus Q&A. Got it, got it, got it, got it, got it.

Yeah. And producer Richard is going to be joining us too. And I know I promised it last time, but we are actually doing anti-matter. Okay. I thought you teased with that. I was like, I love the got anti-Mat. And then I realized that we, if we did that, we would miss the Pluto and of a lot of,

anniversary. Oh, okay. Yeah, we couldn't, we can let Pseyside like that. Yeah, we couldn't let that happen. That is fine. Again, contact is if you try some astronomy at home. It's at SupermassivePod on Instagram or you can email your questions to podcast at r.r.ac.org or put them in the YouTube comments and we'll try and cover them in a future episode. But until next time, everybody, happy stargazing.