Strange Spins and Cosmic Rings: Exploring NGC 4698 and Chariklo's Secrets

0:00Andrew Dunkley Hi there. Thanks for joining us on yet

0:01 another edition of the Space Nuts podcast. My name is Andrew Dunkley, your host and it's good to have your company as we look into these, uh, issues, you call them issues stories. Uh, there's a really weird galaxy out there. It's got a really odd rotational pattern, uh, and one wonders why. I have a theory, but it's probably wrong. Uh, we're also going to look at the changing rings of Chariklo. What is that? It's a weird thing in a weird place I think is the best way to describe it.

0:35 And we don't need to talk about it anymore. And we've got a juicy story from ESA as well. That's all coming up on this episode of Space Nuts.

0:44Professor Fred Watson 15 seconds. Guidance within channel

0:47 N9. Ignition sequence star.

0:50Professor Fred Watson Uh, SpaceNets. 5, 4, 3, 2, 1. 3, 3, 4,

0:54 5, 5, 4, 3, 2', 1. Space Nuts astronauts reported. Neil. Good.

1:01Andrew Dunkley Actually, we've got a couple of stories from

1:02 ESA today. Joining us to explain all of that mystery that I just unveiled is Professor Fred Watson Watson, astronomer at large. Hello Fred Watson.

1:11Professor Fred Watson Good morning. Uh, uh, what's your name again?

1:13 Andrew. Yeah, that's it, sorry. Dave.

1:16Andrew Dunkley Dave. I've copped that many times. I still

1:19 get that now. That was years ago that somebody accidentally calls me Dave. And it's still going.

1:25Professor Fred Watson Part of Space Nuts legend is that

1:28Andrew Dunkley my best friend's name is Dave. So I'm not

1:31 offended.

1:31Professor Fred Watson Uh, could be, actually. Um, I've got several

1:34 really close friends who are Dave's as well, so must be what it is. Anyway, Dave, it's nice to talk to you again.

1:41Andrew Dunkley Thank you, Fred Watson.

1:43Professor Fred Watson Um, I usually get Frank.

1:47Andrew Dunkley Do you?

1:47Professor Fred Watson Uh, sometimes I get Greg. Yeah. When people

1:50 m. Mishear the consonants. Okay, so it's when you, you know when you go and order a coffee and they say what's your name? So they can yell out your name when your coffee's ready. Yeah. And um, so I expect Greg or you know, Ted or anything that's got different consonants. And occasionally I get Frank as well.

2:10Andrew Dunkley Well, my elder, I've got a better one than

2:12 that. Uh, my eldest son's name is Kyle. K Y L E. And uh, this turned into a Facebook, um, epidemic, uh, at one stage where he'd go and order a coffee down in Sydney somewhere and then they'd call out Kylie, Kylie. And they'd even written Kylie on the car.

2:33Professor Fred Watson Ah, yeah, yeah.

2:34Andrew Dunkley And every time it happened he'd take a photo

2:36 and go put it on Facebook and go what the bleep? And it still happens. To him. But he's been down there for, I don't know, 15 years now. And, um, he still gets called Kylie.

2:50Professor Fred Watson I don't understand. Could be there.

2:52Andrew Dunkley Anyway, he hates us because we named him, so.

2:55 Anyway.

2:55Professor Fred Watson Yeah, yeah. Why did he call him Kyle?

2:58Andrew Dunkley Uh, that's a funny story too, because, uh,

3:01 when Judy fell pregnant and I'm still trying to find the man that did it. Anyway, um, when Judy fell pregnant, we were sitting in the lounge room saying, what are we going to call him? And we were watching the movie the Terminator. And the original one, the very first one, and the. And the, um, hero's name in that was Kyle. I said, that's a nice name. And Judy said, yeah, yeah, let's go with that.

3:26 So it's from the mo Movie the Terminator. There's. There's no family connection whatsoever with the name. We just liked it from the film.

3:37Professor Fred Watson I thought you might. There might be a link

3:39 with Scotland there. Uh, no, Kyle is an estuary. Oh, is it kind of local? Of Sutherland. Yeah. So he's an estuary. That's his name.

3:49Andrew Dunkley I mean, there's a bit of Scottish heritage in

3:51 our family, so that probably works.

3:53Professor Fred Watson That'll.

3:53Andrew Dunkley That'll do.

3:54Professor Fred Watson Yeah. Yeah.

3:56Andrew Dunkley And our other two, we. We picked Morgan for a

3:58 girl and never had a girl. So when we had our second boy, we went, well, let's just use that just in case. And then the third one came along and we were. We were still devoid of names. And I said, well, why not Lachlan? You know, we're not far from the Lachlan River. Let's just stick with Lachlan. So that's how that happened as well.

4:17Professor Fred Watson Yeah.

4:18Andrew Dunkley Yeah, it is. It is, yeah.

4:20Professor Fred Watson There you go.

4:21Andrew Dunkley Hmm. Yeah. I hadn't thought about

4:24 how we named our kids, and I haven't thought about it for years. And they never asked, so I. We don't go there.

4:32Professor Fred Watson We'll do another episode, uh, down the track

4:35 and I'll tell you how, uh, we. Why we named our kids. All right. Yeah, no, we won't do it now. We won't do it now.

4:42Andrew Dunkley We'll do it in the next episode.

4:43Professor Fred Watson Do it in the next episode.

4:45Andrew Dunkley We should do some stories, though. Um, now

4:48 this. This one's really weird and it's all to do with observ of a very strange, uh, galaxy, uh, that's behaving badly. Or is it just behaving strangely? Has it had too much to drink? Fred Watson?

5:03Professor Fred Watson It could be. Certainly. It probably is a

5:06 digestive issue, uh, for the galaxy.

5:08Andrew Dunkley I was gonna Say that that was my theory. I

5:10 bet this is a result of a galaxy merger.

5:13Professor Fred Watson Yeah, I think that's right. That's the

5:15 general view of it. So the galaxy we're talking about, it's actually not. It's a nearby galaxy. It's um, 55 million light years away. That's very much uh, our uh, local backyard. So the images that we see of it are very, very detailed. There's a beautiful image, uh, which I think is on both the ESA and NASA website because it's a Hubble telescope image. And of course the Hubble telescope is um, um, funded by both and uh, operated by both. Um. Uh, it's a spiral galaxy, uh, in the constellation Virgo. As I said, 55 million light years away. Uh, it's one member of the Virgo Cluster, which is one of the biggest nearby galaxy clusters that we can see. Um, there's something like a thousand galaxies in it. Um, there are a

6:03 few really big ones, the Coma Cluster, uh, Virgo Cluster, a few in our locality. And they're big, they're big, um, galaxy clusters. So um, when you look at this, there's a lovely Hubble telescope image that I guess is the centre of uh, attention on this story. Um, beautiful image of this galaxy, spiral arms, which unlike the spiral arms of our Milky Way galaxy, we think they are at their inner edge firmly pinned down to the um, central bar of the galaxy. That means when you look at it, and we clearly can't look at our own galaxy in a photograph because we're right inside it. Uh, we can't look at the whole thing but we can map it through infrared and radio astronomy. And um, the evidence seems to be that there is a bar,

6:57 uh, at the centre. Now that's not a bar you lean against. It's an elongated distribution of stars, uh, and um, with some really interesting dynamics, really interesting movement in it. Uh, but our spiral arms, uh, are uh, sort of fixed to the end of the bar. That's where they seem to originate from. Um, whereas with ah, this particular galaxy, and I haven't given it its name, it is NGC 4698. A uh, lovely, um, meaningless name. Um, uh, NGC stands for New General Catalogue which if I remember rightly was published in 1888. Uh, so it's still pretty new really. NGC 4698. Uh, the point about this galaxy is when you look at it you can see spiral arms, but they're sort of only in the outer, I guess the

7:47 outer third of the galaxy. And in the middle there's no sign of spiral arms. So that straight away tells you that there's something different about this object. Um, the other thing, and the thing that is, I guess, really remarkable is what we slightly unflatteringly refer to as the bulge of the galaxy. Um, our galaxy has a bulge.

8:10 Uh, it's, uh, what is often known as a peanut bulge because it's kind of vaguely peanut shaped. And that probably comes about because of the, the bar in the centre of our galaxy. Uh, we see it from our vantage point here in the solar system. We see it in the constellation of Sagittarius. And, um, if you look on winter nights at the Milky Way, when it's nearly overhead, that's where it is at its widest. There is a sort of big swath of stars there and that's the bulge of our own galaxy. So you can kind of see it with the naked eye.

8:45 Uh, this one has a bulge as well, which is elongated a bit like ours, but it's elongated in the wrong direction. It stretches out perpendicular to the disc of the galaxy. And that is a rarity. I don't think it's unique, but I think it's pretty rare. Uh, and so what, um, is perhaps the smoking gun about how this originated is that when you look at the movement of stars within that perpendicular bulge, um, you find that the motion of the stars is perpendicular to the rest of the galaxy as well. So it's not just that it looks as though it's at right angles, it really is because the stars are moving in that direction, uh, up and down through the centre of the galaxy, rather than, uh, swirling around in the same plane as the disc

9:43 of the galaxy.

9:44Andrew Dunkley Yeah, I don't, you know,

9:47 is that possibly a rarity or is this most likely more common than we think we've just happened to find? The first one that looks this way.

9:56Professor Fred Watson Uh, yeah, that's a good question.

9:57 Is it, um, you know, is it a selection effect that we normally don't see that. But I think it is more likely that this is quite rare because, um, certainly the imagery of this object, uh, is very striking. When you look at it, you can see straight away that its bulge is different from, uh, normal galaxies, that it's got this, uh, sprinkling of stars which are well above the plane of the galaxy and that's not what you expect from, uh, the bulge.

10:30Andrew Dunkley So you can see it in the image. It's a

10:32 beautiful image, by the way, isn't it?

10:34Professor Fred Watson Isn't it lovely? Um, there's other

10:37 fainter galaxies in the background, which, um, are always nice to see, it looks as though, um, uh, the dust is showing up very clearly, uh, reddish in this image. And that's probably a true colour as well. So it looks like the dust looks like gravy swirling around, uh, the spiral arms at the outer side of the galaxy. But, um, yes, it's a very, very, uh, attractive image.

11:04 So, um, the reason possibly is that maybe there was a collision. Uh, and we know that galaxies have grown by sort of gobbling up smaller galaxies. And if this collision took place at, uh, this high angle, uh, so that you've got a dwarf galaxy perhaps being absorbed by, uh, uh, NGC 4698, um, then you might very well get these velocities which are perpendicular to the disc of the galaxy. Um, we've got a similar situation in our own galaxy with the Two Magellanic Clouds, the dwarf galaxies. They're quite big for dwarf galaxies, actually. Uh, but they still count as that. Uh, they are visible in our southern hemisphere sky. They are being absorbed by our own galaxy. And there's a sort of something called the Magellanic, uh,

12:01 stream, which is a stream of stars between them and connecting with the disc of our galaxy. And they're at a relatively high angle. So maybe in a few hundred million years, when space nuts will still be going, uh, we might have a similar phenomenon in our own galaxy. A bulge that's modified, that sticks up. Uh, although we've got a bar as well in the middle, which is a fairly robust feature. I think as the galaxy evolves, that will stay pretty solidly there. So we might end up with two bulges.

12:32 Who knows?

12:33Andrew Dunkley You never know. Yeah, so this one's, uh,

12:36 quite, quite amazing. And, uh, uh, you can read all about it on the European Space agency website. That's ESA.int and just do a search for, uh, NGC 4698, I think, would be probably the easiest thing to do, Fred Watson.

12:53Professor Fred Watson Yeah, Or, I mean, the title of their press

12:56 release is lovely. A Galaxy Spinning out of Sink. I like that.

13:00Andrew Dunkley Yes.

13:01Professor Fred Watson Yeah.

13:01Andrew Dunkley Or it fell down a sink or something.

13:04 Those tend to spiral as well.

13:06Professor Fred Watson Yes, well, they do. That's right. Yeah.

13:08Andrew Dunkley Indeed.

13:09Professor Fred Watson Two different sinks.

13:11Andrew Dunkley Have a look for it. Uh, this is Space Nuts

13:13 with Andrew Dunkley and Professor Fred Watson Watson. Okay, we've had a problem here.

13:18Professor Fred Watson This is Houston. Say again, please. We've had a problem. We've had a B pup on a vault.

13:24 So we're looking at it.

13:26Andrew Dunkley Space Muffs. And I've got to say

13:29 hello to a couple of our live viewers. Uh, Emily is, uh, watching us from a taxi in Perth at the moment on her way to a conference or a training course, I think. And, uh, yeah, so, um, yeah, the places we tune in from, I guess we're all nuts. She says, hi Emily. And, uh, Sophie's listening to us, uh, from, uh. Now, where did she say? Doesn't, uh, say where she's from, but she does ask if we'd heard about the potential closure of the Jodrell bank facility. Oh, she's in Somerset in the uk. Hi, Sophie. Yes, we, we were very much aware of that. That's been brought to our attention by a couple of listeners recently. Yes, and very sad news. Very sad news indeed.

14:13Professor Fred Watson Except that we think it's been the, the, the

14:16 prime. The Prime Minister mentioned it in Parliament about two weeks ago, saying that, uh, every school kid of his generation went to visit Jodrell bank and there's no way he was going to see it being closed in his watch.

14:28Andrew Dunkley That's good news. There you go, Sophie. So,

14:30 um, it may well be saved. Yeah, that would be wonderful. Um, lovely to have a live audience. It's becoming a new trend for us.

14:38Professor Fred Watson Isn't it great? Yeah, it's absolutely

14:40 fantastic.

14:41Andrew Dunkley Terrific. Let's go to our next story,

14:44 and this one's a little bit weird, and I'll try and pronounce this correctly, but we're talking about an object named Carricklo. Uh, now, um, the story is about the rings around Chariklo that are. That are changing. But we better firstly explain what this object actually is.

15:06Professor Fred Watson Uh, yes, that's a, uh, nice way to

15:09 introduce the story because, um, Chariklo is not one that we talk about very much. Uh, its full name is one zero one. Um, nine. Nine Chariklo. And the fact that it's preceded by a number tells you that it's an asteroid. Uh, uh, every asteroid, uh, has a number as well as a name like 5691. Fred Watson Watson.

15:28 Sorry, couldn't resist it. So 10199 curriculo. Um, but it's not, uh, an asteroid. Ah, Fred Watson Watson, by the way, is probably the single most boring object in the solar system. It is in the main asteroid belt. It never does anything, uh, just sort of circulates around the sun. Um, there's not really anything to, you know, to make it stand out and it definitely won't hit the Earth anytime soon. Uh, Cariklo, on the other hand.

15:57Andrew Dunkley Wouldn't it be ironic though if it hit Earth

15:59 and hit your house?

16:03Professor Fred Watson I probably told you this story before when

16:06 more than 20 years ago now, when it was announced that the IAU was naming an asteroid after me. I went home from the observatory, told my two young sons that that was what had happened. They said, dad, that was terrible. If it hits the Earth, it'll be your fault. Um, and, um. So, yes, I've had that hanging over my head, uh, ever since. It will never, ever hit the Earth. The dynamics of the solar system are such that it will remain, as I said, probably the single most boring object in the entire solar system. Unlike Curriculo, um, which, uh, is, uh. Actually, it's called a centaur.

16:41 That's a class of asteroids and this is the biggest of them. Curriculo. It's probably 250 kilometres across itself. A large ish asteroid. Um, and they orbit, uh, between the orbits of Saturn and Uranus. Uh, ah, that's the centaurs. Uh, this particular one, Chariklo, has an orbital period of 62 and a half years. That's how long it takes to go around. Once actually discovered back in the 1990s at Kitt Peak National Observatory in Arizona. Uh, it's got a, uh, dark reddish surface.

17:15 Um, uh, uh, this brief update comes from Wikipedia just so I can get all the facts in there. It's got water, ice, silicate minerals, amorphous carbon and various complex organic compounds known as solins. Actually, uh, so these are the things that make many of those very distant trans. Neptunian objects, like, um, our old friend Arrokoth, the most distant object that's yet been visited by a spacecraft. Quite a, uh, reddish reddy brown surface.

17:49Andrew Dunkley Yeah, SEDNA is like that too, apparently.

17:52Professor Fred Watson That's right, yeah. It's common. It

17:55 comes about because of the, uh, um, bombardment by subatomic particles from the sun and also cosmic rays, which come from outside the solar system, uh, over, uh, many billions of years. Like the four billion year history of the solar system. A four and a half billion year history. Um, and that modifies these chemicals to give you this brownish colour. So, um, there are, uh, uh, rings around Curriculo. I think it may have a moon. Um, I have that wrong, but it certainly has rings.

18:34 Uh, maybe it doesn't have a moon. Sorry, M. I don't want to mislead anybody.

18:38Andrew Dunkley Um, I'll tell you in a second. No,

18:42 it does not have a confirmed moon yet, is the answer.

18:46Professor Fred Watson Yeah, well, that's right. It's a long way

18:48 away. It's beyond the orbit of Saturn. An object only a couple of hundred kilometres across, uh, smallish object. Um, uh, but it's got rings. And uh, how do we know that? By this marvellous technique, uh, that I always think is a great way to find solar system objects and measure them. Sometimes what we call occultations. When, uh, a solar system object passes in front of uh, a distant star and so its light is blocked, the light of the star is blocked. And if you have enough people observing the occultation, you spread them out across, well, sometimes across a nation like Australia, uh, you can essentially uh, see the dip in light, uh, and map it. Map m whatever it is that's uh, obscuring over uh, this area

19:42 of the land where you've got observers. So you get all the observers to time when the background star seems to disappear and reappear. And by doing that, by plotting all those timings on a map, you can actually get the shape of whatever it is that's occulting or blocking out the light of the star. And back in 2013, uh, Kuriklo, uh occulted a star and it was seen that there were sort of symmetric occultations on either side of the main object which tell you that you've got rings. So that's the backstory. Uh, the front story is that uh, curricula has now been observed or occultations have now been observed by the James Webb Telescope, which of course is a very powerful instrument.

20:36 And so you get very, very sensitive light curves or very detailed light curves. And what they're finding is, uh, that its rings have changed. They've changed significantly since that um, 2013 discovery. Uh, um, it basically uh, is a very nice occultation because it misses the curricula itself. Curricula, uh, didn't dim the star, uh, because the line of sight to the star from the James Webb telescope was uh, about seven kilometres above the Curriculo's surface. We're talking in very small distances here. So that the rings of Curriculo, and I didn't mention that there are two, not just one, there are two, uh, which crossed, uh, passed in front of the star, uh, and uh, were able to be measured um, by

21:32 the James Webb Space Telescope. Some very nice observations, uh, of that. And uh, what we now know, uh, is that the rings have changed, as I said, since 20. Um, and so what we've got is a darkening of the inner ring, uh m sort of more so than would be expected. Uh, there have been other observations since 2013, uh, in 2014 and 2017. Um, so these, you know, uh, the observations allow uh, us to see the way things uh, change. The astronomers who've done this work do make the comment though that maybe these rings are unequal in density. Uh, so if you've got, you know, the rings are made of material, just dusty material, uh, in orbit around the parent star. Uh, but there can be regions where there's more dust than there is further

22:32 along the ring. And so it may be that uh, we've, you know, that they, that's what they've seen, a more dense region. Uh, but um, doing a statistical um, analysis of that suggests that that's probably not the case. That it probably is a real effect that the rings are actually um, that you know, the rings themselves are changing in structure.

22:59Andrew Dunkley Yeah. Interestingly Fred Watson, we

23:02 mentioned um, earlier about whether or not it had a moon. There is a hidden moon hypothesis, uh. Ah, yes, attached to this uh, object. And um, uh, some astronomers believe a tiny moon about two miles across, three kilometres, ish, uh, is orbiting inside or near the rings. And its gravity acts like a sheepdog, cosmic sheepdog they say, containing the icy particles so the rings stay intact. That's one theory, yes.

23:33Professor Fred Watson Uh, and

23:36 um, certainly um, this research uh, mentions that partly because um, there are resonances here and we've talked about resonances before. When you've got one thing that orbits, for example, um. Well, if you've got moons orbiting like Saturn as resonances, one moon will orbit uh, twice for another moon going around three times. These are uh, what we call resonances. And apparently uh, one of the rings is a uh, one to three resonance with curricula itself.

24:15 So you've got a ring particle going around once for every three rotations of curricula. And that could shape the structure of the rings. Um, but that in itself might be caused, exactly as you've just said, by what they call a shepherd satellite. An unseen moon could perhaps uh, help to keep the ring intact. Uh, exactly as we see in some of the tiny moons of Saturn, which are almost embedded in Saturn's ring system. So yeah, this is um, really interesting stuff. Uh, if you're an asteroid fanatic, uh, um, with these possibilities, um, imagine what something like that would look like if you could stand close to it. Because curricula itself is probably a fairly irregular object.

25:00 It is big enough to be more or less spherical, but um, we don't know its true shape. That's something else that can be gained by the way, by occultation measurements.

25:10Professor Fred Watson Mhm.

25:10Andrew Dunkley The other interesting thing is um,

25:13 the belief is those rings will disperse eventually.

25:18Professor Fred Watson Yeah, exactly as we think with Saturn. Ah,

25:21 but I think these might have a relatively short timescale. I can't remember what sort of timescale.

25:27Andrew Dunkley Uh, a few million years

25:30 Is the, the theory.

25:32Professor Fred Watson Relatively short. Saturn's rings are expected

25:35 to disperse within the next hundred million years or so. It's in the diary. I've got it in my diary. I hope you have too.

25:42Andrew Dunkley Uh, yes, I have, yes. Um, when they say

25:45 disperse, what does that mean? They're just going to go drifting off into space.

25:48Professor Fred Watson And probably in um, maybe,

25:51 I suspect in both cases it will be a question of them collapsing onto the, gradually collapsing onto the surface of the body itself. We know that um, the inner edge of Saturn's rings are uh, basically raining down into Saturn. We saw that with the Cassini spacecraft. Direct evidence of that. A kind of rainfall of ice from the inner edge of the rings, uh, heading down towards the planet. And I suspect that's what will happen with Curriculo. Uh, the rings will end up on the surface. We think, and you and I have covered this on space knots, there might be evidence that the same thing happened on Earth billions of years ago.

26:31Andrew Dunkley Interesting. If you'd like to read all about

26:34 it, you can find out about uh, Curriculo's rings on the Brighterside News website. This is Space Nuts. Andrew Dunkley here, Fred Watson Watson there.

26:49Professor Fred Watson Amen. Space Nuts.

26:52Andrew Dunkley Now Fred Watson, we turn our attention to the

26:55 JUICE mission. This is an ESA mission to Jupiter, uh, to look at its uh, it's moons and uh, it's about to do something. By the time this podcast is out, um, Juice will have done the, something that we're talking about doing.

27:11Professor Fred Watson Right? It will, it'll have

27:13 done it, it'll have done its thing and uh, uh, successfully, we hope so. Juice, uh, it's a really juicy topic of course. We can't resist, uh, that. I uh, had a nice glass of orange juice a couple of hours ago as well, which was good. Anyway, um, it's um, uh, it is the European Space Agency's Jupiter Icy Moons Explorer. That's where the name comes from. Uh, and uh, it's heading for Jupiter. Uh, if I remember rightly, it will orbit the planet itself, making frequent flybys. Um, uh, there is NASA's probe which is also uh, looking at the ice moons. Uh, that is Europa Clipper, that's called.

27:56Andrew Dunkley That's right, yeah.

27:57Professor Fred Watson That will also be in orbit around

28:00 Jupiter. Anyway, Juice, um, is heading out to Jupiter but it's been on its way there for three and a half years. Uh, and um, given that it was launched in April 2023, uh, in French Guiana. That's where, uh, the ESA Space Port is. And what it's done in the time since then. Uh, first of all, it did, uh, a lunar Earth flyby. Um, in other words, kind of taking the gravitational pull of both the Moon and the Earth into account. Uh, then it did a Venus flyby and you think, wait a minute, Venus isn't on the way to Jupiter.

28:42 It's the other way.

28:43Andrew Dunkley Here we go again.

28:44Professor Fred Watson Yeah, here we go again. But that's how you do

28:46 these gravitational assists, uh, that um, actually increased its speed. Uh, and I think I'm right in saying as we stand here now, there are two more flybys of Earth. Uh, one on the 28th of September, um, which is as we're speaking now in the future, but perhaps won't be by the time our listeners hear this, except for our live audience who are hearing it now. Um, and welcome again.

29:11Andrew Dunkley By the time this one goes out, this episode

29:14 goes out, what we're talking about will have happened last week.

29:17Professor Fred Watson Okay, so last week there was another flyby

29:20 of the Earth, um, coming within, uh, actually less than 9,000 kilometres of the Earth's surface. That is very close. Uh, and that sets it up for a, uh, gravitational. Final gravitational assist in January 2029. A, uh, couple of years down the track, three years down the track, um, or two and a half. Um, and that will put Juice on its, uh, sort of, um. I guess the best way to describe it is on the fastest part of its journey because it will then head off towards Jupiter, uh, and intercepting the orbit of Jupiter in July 2031. Uh, so a long and complicated journey. Still simple compared with BepiColombo, uh, which is now in the region of Mercury after I think. Was it eight or nine gravitational assists?

30:13Andrew Dunkley It was nine. Yeah.

30:14Professor Fred Watson Nine. Yeah. Um, so, uh,

30:18 it's actually um, one of these things that uh, uh, we almost certainly won't notice it. Uh, but at that height, uh, it's uh, possible that people who know how to find the trajectory in the sky using, uh, telescopes or even binoculars might be able to track it. And there is a link on the European Space Agency's, uh, media brief on this, a link to tell you how to find the trajectory. So, uh, head to, uh, the page called Juice to fly past Earth for a third gravity assist. Uh, which might have been revised to Juice flew past Earth for a third gravity assist.

31:03Andrew Dunkley It might.

31:05Professor Fred Watson In which case you don't need to know where

31:07 its trajectory is. But anybody who's listening live now can find that trajectory data on that website. I think there's at least two people who are listening.

31:15Andrew Dunkley It's a very exciting mission.

31:16Professor Fred Watson Can't wait. It is, isn't it? Yeah.

31:19Andrew Dunkley And, and such a complicated way to get

31:21 somewhere. But, uh, probably no more complicated than catching suburban trains. So, um, you know, sometimes you have to go out there to get back there, but.

31:31Professor Fred Watson Yeah, that's right. Yeah, indeed.

31:33Andrew Dunkley But, yeah, yes, uh, it's on the ESA website

31:35 if you want to check it out. The Juice mission. Um, yeah. Uh, and who knows what it will reveal? We just gotta be a bit patient. We've got a few more years to wait yet. That, uh, brings us to the end. Fred Watson, thank you very much.

31:50Professor Fred Watson Uh, you're welcome, Andrew. It's been a joy

31:52 to talk to you again and to our, uh, listeners and to the audience who will eventually see this, uh, long after Juice has come and gone.

32:00Andrew Dunkley Yes, indeed, professor, um, Fred Watson

32:03 Watson, astronomer at large, part of the team here at Space Nuts. Don't forget to visit our website. Uh, in the meantime, you can send us a message on the Ask me Anything link at the top that's labelled ama. Uh, you can check out the shop. Uh, you can, um, subscribe to the Astronomy newsletter or, or. And, uh, you can, um, do something else that I've completely forgotten about. Hate it when that happens. Anyway, and thanks to Huw in the studio who couldn't be with us today. He, um, he grabbed some juice and now he's 156.7 million kilometres away.

32:41 He'll be back next week and from me, Dunkley, thanks for your company. We'll see you on the next episode of Space Nuts.

32:47Professor Fred Watson Bye.

32:48Andrew Dunkley Bye.