The Supermassive Podcast - 21: Icy Worlds

Episode Date: October 1, 2021

Wrap up warm, because this month Izzie and Dr Becky are exploring the icy worlds in the solar system. To help, they're joined by Caroline Harper, Head of Space Science at the UK Space Agency, to discuss the new mission heading to explore Jupiter’s icy moons. And they hear from Professor Michele Dougherty from Imperial College London, who sent Cassini to investigate Saturn’s moon Enceladus. Plus Dr Robert Massey takes on your questions and shares his latest stargazing tips for autumn. Join the Royal Astronomical Society's livestream of Uranus, 8th-10th October 2021: https://www.eventbrite.co.uk/e/the-weird-and-wonderful-world-of-uranus-world-space-week-tickets-183281298297 Thank you to the UK Space Agency for sponsoring this episode. The Supermassive Podcast is a Boffin Media Production by Izzie Clarke and Richard Hollingham.

I love the moon. Everyone knows that. But love it a little bit more now. We actually made a really cool discovery. So if we're looking for extraterrestrial life, what better place to start than the giant ocean? And it's dubbed a hot ice world. Hello, welcome to the Supermassive podcast from the Royal Astronomical Society. With me, science journalist Izzy Clark and astrophysicist Dr. Becky Smethurst. And thank you to the UK Space Agency for sponsoring this episode.

All right, time to wrap up warm Izzy because this month we're exploring the icy worlds in our solar system. And to help us, we'll be joined by Caroline Harper, Head of Space Science at the UK Space Agency. We'll be chatting to her about the new mission heading to explore Jupiter's icy moons. And we'll hear from Professor Michelle Doherty from Imperial College London,

who sent Cassini to investigate Saturn's moon Enceladus. And last, but by no means least, Dr. Robert Massey, the Deputy Director of the Royal Astronomical Society, is here too. So, Robert, what do we classify as an icy world? Are we talking about worlds that permanently look like a winter here on Earth? Well, I don't think you have to necessarily think about it as just being like a cold Earth,

although that would obviously be a classic example of an icy world. And there is this idea that 600 million years and more ago, the Earth was like that. It was, there was this snowball Earth idea when there were glaciers all over the planet. And I think if you were an astronomer looking at it from a distant star, you would definitely see it as an icy world. But in our own solar system, we can be talking about things like the moons, some of the moons of Jupiter and

Saturn, like Europa with a dirty, great, thick 20 kilometer ice crust above an ocean. Enceladus around Saturn, which shoots geysers of water into space, but again has got this big, thick ice crust. And we also talk about Uranus and Neptune as ice giants too. So you don't, although it is a category, you can think about this sort of, you know, somehow Narnia in the depths of winter. You could also think about just cold planets too,

places that are so far from the sun that at least the top of their atmosphere is really very cold and deep. I mean, that's a book I want to read, Narnia in Space. Yes, please. Well, we need to pitch this, don't we? We'll add it to our list of sci-fi, yeah. Cheers, Robert. We'll catch up with you later in the episode.

Glaciers, ice mountains and vast canyons mould these worlds of ice. But how much do we know about them and what missions can tell us more? I spoke with Professor Michelle Doherty from Imperial College London, who started by explaining how common these icy worlds are. They're actually more common than we originally thought. And we see them in a number of the moons around the outer planets in our solar system. So around Jupiter and Saturn, and Uranus and Neptune as well. What did these worlds look like? What makes these worlds icy? Talk me through it. Okay, so the way that I think about icy worlds is it's any planetary body in our solar system and beyond the solar system where you don't have liquid on the surface, but you have an

ice form of that liquid instead. You've got lots of topography. So you've got mountains, you've got valleys, you've got old riverbeds. On some of the bodies, you might have bits of ice that move around. One of the views that I really like is of Europa, one of Jupiter's moons. When we were able to fly, if you fly over the Greenland ice shelf, you see bits of ice breaking off from the edge of the ice shelf. And that's what the surface of Europa looks like in parts as well.

Yeah, it might be a simple question, but why are they icy? Is it purely because they are just further away from the sun and they're at these outer planets? That is our understanding of them. Yeah. I mean, from my perspective, and when you said it might be a simple question, it's always a simple question, difficult ones to answer. From my perspective, I think the biggest discovery that we have made in planetary science in the last 30 years or so is the fact that, you know, planetary scientists search for liquid water, because if you think of liquid water, you think of life. And the focus had really been on planets close to the sun, because if you're looking for liquid, you need to be close

to the heat source, which is the sun. But what we found with various planetary missions like the Galileo spacecraft at Jupiter and more recently the Cassini spacecraft at Saturn is that you can find liquid water underneath the surface of the icy bodies. And so they're icy because they're far away from the sun, but there is an internal heat source that is making the ice liquid underneath the surface. And so there's now been a real change as far as focus for search for habitability. You don't have to be close to the sun. We can be searching much further away from the sun. But let's focus on Saturn's icy moon.

This is something you've worked on. So what are they? What do they look like? There are lots of icy moons of Saturn. I think at the last count, there are about 65 or something. But the ones of interest that Cassini focused on were Enceladus, which I'm going to talk a bit about in detail, Titan, the largest moon of Saturn. And Titan is the one where the European Space Agency, Huygens Probe, traveled down through the atmosphere and landed on the surface. There are a whole range of moons, most of which have got icy surfaces. But I think for me,

my favorite is Enceladus. And the reason for that is with the Cassini spacecraft and the magnetometer instrument that I was responsible for on the Cassini spacecraft, we actually made a really cool discovery. And that was the fact that there's outgassing of water vapor from the South Pole of Enceladus. It looks a bit like a cometary plume of water vapor. What was it looking for? What were you aiming to find? I was really fortunate. I became involved just after launch. And what this instrument does is it measures the magnetic field in the environment of the spacecraft. And you might be thinking to yourself, how on earth can a magnetometer discover there's water

vapor leaking out from the moon? The way that we did that is what we found is as we flew close to Enceladus, we found that the magnetic field of Saturn, which should have not noticed Enceladus was there, seemed to be draped around Enceladus. Something was stopping it from penetrating down onto the surface. And in addition to that, we saw a lot of wave activity in the data. And that wave activity was linked to a large increase in water group ions. And so this was telling us effectively that Enceladus was acting as an obstacle to the flow of plasma and the magnetic field coming from Saturn. And it was when we got really close, after we persuaded the project to take us really close that we saw that there was this outgassing of water vapor coming from the south pole so from my perspective and i'm not

biased at all a magnetometer instrument is the most important instrument on any planetary mission yeah absolutely i won't argue that i didn't think you would thank you um so what did that feel like you know how break break the mission down for me. You need a lot of patience to be involved in outer planetary missions. So we were launched in October 1997, took us six and a half years to get to Saturn, almost seven years. So we arrived there in July 2004. And it had always been planned that in the first six months of 2005, we were going to fly past Enceladus on three separate occasions, just to see what it is that we could find.

And on the first two flybys, which were quite distant flybys, we saw these strange signatures in the magnetic field. I was a little worried because I hoped we had calibrated our data properly. We talked in the team about what it is that we thought we might be seeing. And one way that we could describe the observations was if Enceladus had an atmosphere, a bit like the atmosphere on the Earth. The upper regions of the atmosphere become ionized by solar radiation and that stops the magnetic field of the solar wind penetrating through.

So what we did is we put a schematic together to show what we thought was going on. And in fact, there was a science meeting being held at the Jet Propulsion Lab about a month after the second flyby. And I went out to JPL and I was going to give a presentation to the team there and try and persuade the project to change the third flyby altitude from 1,000 kilometers to about 170 kilometers above the surface. Oh, so really close. Really close. And I was really nervous about doing this because, you know, we'd spent the six and a half years it took us to get to Saturn planning every second of the observations we were going to make. So if we changed the trajectory of the spacecraft, that meant some of the instruments wouldn't be taking the data they were hoping to get. I was jet lagged

to help, decided I needed a cup of coffee. So I went and stood in the line at Starbucks. And the man standing in the line in front of me turned around to me and said, Michelle, what are you doing here? And it turned out it was Jerry Jones who was responsible for the safety of the spacecraft. And I told him why I was there. And he rubbed his hands together in glee and he smiled and he said, I've always wanted to go closer to a planetary body than anyone else. So I knew I had one vote in my back pocket. That's amazing. Not everyone thought it was a good idea to do, but the majority of the team said, yes, let's go ahead and do it.

And so the project changed the flyby altitude, so it really essentially skimmed below the South Pole. And the reason it went below the South Pole was not because we thought anything was happening there, but because that used the least amount of extra fuel to do that. But it was great that it went below the South Pole because that's where the cracks are. And that's when we realized it wasn't an atmosphere covering the entire surface,

but there was essentially this outgassing of water vapor at the South Pole. And I must confess for the couple of nights before that flyby, I didn't sleep very well because if we had found nothing, no one would ever have believed anything I said again. Yeah, but then you find these amazing jets of vapor coming out from these cracks. So what's the next steps in terms of exploring icy worlds?

Are there plans to explore Saturn's moons further? Yes, there are. In fact, there is a NASA mission called Dragonfly, which is going to focus on Titan, which is the large moon at Saturn. We've got liquid ethane and liquid methane on the surface, but we've got liquid water underneath the surface. But I think for me, the next steps, as far as icy worlds are concerned, and I know you're going to talk about this more in the second part of the program, is JUICE, the European Space Agency mission to Jupiter and its moons. For me, it's getting an understanding of the internal structure of these moons, whether there's organic material there and what we might want to do when we go back

in the future, where it is we want to focus on. That was Michelle Doherty from Imperial College London. So Becky, what are some of the coldest temperatures we see across our solar system? Yeah, so there's a couple of things that can take maybe coldest temperature. If you're talking first about the coldest planet, right? There's a bit of contention here, it turns out, right? You'd think that the coldest planet would be Neptune, right?

By virtue of it being furthest from the sun. But Neptune only has the coldest average temperature like overall at minus 200 celsius a little bit right but in terms of the coldest single temperature Uranus actually takes that ground there with a lower like minus 224 celsius so just a couple of degrees lower right than that than Neptune just sort of hits it to the post then you've obviously got the coldest recorded temperature on a dwarf planet I know some people would always want me to think about dwarf planets because of Pluto but it's not Pluto Pluto doesn't take the coldest dwarf planet crown it's actually um pause before I say this

because I always say it wrong make makemake. Right. Which I honestly thought was pronounced makemake for an embarrassingly long amount of time until I was like 30 years old. And seven years as a professional astronomer. Makemake. Makemake is minus 243 Celsius. Wow. So, I mean, it's getting really cold, right? But the lowest temperature ever recorded anywhere in the solar system is actually a little bit closer to home. It's our very own moon.

In 2009, the Lunar Reconnaissance Orbiter, which is a satellite that orbits the moon, measures the temperature inside a crater, the Hermite Crater, which is right on the north pole of the moon. It doesn't get a lot of sun up there. It gets very, very cold. Minus 248 degrees celsius oh my god which is only yeah it's only 30 degrees above absolute zero right and a good you know what was what was neptune before minus 200 so it's 50 degrees cooler than neptune's average temperature right so i mean you don't look at the moon the same will you no no but i'm

wondering like so why is it that specific crater is colder than you know objects way further out in our solar system yeah it's just about energy that reaches reaches that crater right so it's very shadowed against the sun so there will be literally parts of it that never seen sunlight because they're so shadowed of where it is and also the walls of the crater if you think about units in neptune as well you want to talk about surface temperature necessarily and also the walls of the crater. If you think about Uranus and Neptune as well, you can't talk about surface temperature necessarily. And yes, the outer edges will be very cold. But as you get into the interior of the planets,

they get denser and denser. And obviously things start to heat up as well. So that's the thing is that the moon obviously doesn't have any interior heating. It's not volcanic in any way. And then you've got this region that's just shaded from any sunlight and so it's incredibly incredibly cold. I mean I love the moon everyone knows that but love it a

little bit more now and there is a question here about the potential for habitability so what is it about these icy worlds that make them good candidates to explore that? Yeah I mean weirdly some of what we think are the most habitable places in the solar system are the icy worlds like Titan, Europa, Enceladus, etc. And that's because even though they have these very icy crusts on the surface that are very thick, they have these liquid oceans underneath their crust. So one study actually estimated that the total amount of water on these icy worlds is around about 30 to 40 times what we have on earth so in total on all of them and we know life on earth needs water to thrive right and that it began also in our oceans so

finding how in having water oceans elsewhere even on these icy worlds raises the question of whether there's life in those oceans too especially if there's volcanic activity on the inside as well that could provide a heat source perhaps you might get like thermophilic bacteria that can survive these extreme conditions as well and of course we've seen evidence of volcanic activity on Enceladus right you know one of Saturn's moons for example we have these big geysers from its south pole Cassini flew through them and found they contain minerals and molecules that indicate volcanic activity as well. So people are very hopeful about Enceladus. I personally think it's my favorite moon in the solar system, not just because it's the moon of Saturn, but also because of this extremely cool reason that there could be life there. And so there's really big pushes for

missions to explore these worlds further to try and answer that question of, are we alone in the universe? Are we alone in the universe? So how do we better understand icy moons? We send a spacecraft, of course. In May 2022, JUICE, a.k.a. the Jupiter Icy Moon Explorer, will begin a 7.6-year cruise to Jupiter to spend three and a half years in the Jovian system. I spoke with Caroline Harper, Head of Space Science at the UK Space Agency,

about this mission. Okay, well JUICE is a European Space Agency mission to study Jupiter and three of its largest moons, Europa, Ganymede and Callisto. And it's due to launch next year from the European spaceport in French Guiana. It's going to be carrying a suite of science instruments designed and built by teams of researchers from the UK and across Europe. So we're very excited to see what we can find out about Jupiter and its moons in the very near future. Yeah, so what do we actually know so far about Ganymede, Callisto and Europa? Well, we know from previous observations, they're all very cold, around about minus 140 degrees C, with very thin atmospheres and with thick icy crusts. And we're not absolutely sure, but we believe that under the surface, they could be hiding enormous oceans of liquid water, thousands of kilometers across and much deeper than the oceans on Earth. More water, in fact, than all the surface water here on Earth.

deeper than the oceans on Earth, more water, in fact, than all the surface water here on Earth. We know there are icy moons around Saturn. Enceladus is one that has a subsurface ocean. There's a lot of research being done on that at the moment. Well, now it's Jupiter's turn. So this makes these icy moons some of the most exciting objects to study in the solar system, really. Liquid water is essential for all life here on Earth. So if we're looking for extraterrestrial life, or at least the conditions to support life, what better place to start than a giant ocean? And JUICE is going to give us the data we need to confirm whether the ocean actually exists. Yeah, so what is that data? You know, what is it hoping to find? What's it looking out for? Yes, well, it's's going to orbit Jupiter and there'll be lots of work looking at the atmosphere and the clouds and the weather systems of Jupiter and then it will fly by

two of the moons, Europa and Callisto and then finally settle into orbit around the third one, Ganymede, which is a particular focus for this mission. The UK is involved in instrument development for JUICE and one of the instruments is the magnetometer which has been led by Michelle and a team at Imperial College. We will be using that magnetometer to do a number of things but we'll be focusing particularly on Ganymede because it's pretty special. It's the biggest moon in the solar system, bigger than Mercury, much bigger than our moon. And it's the only one we know with a strong magnetosphere, which is this sort of shield around it to trap and deflect cosmic radiation and particles from the sun, just like our magnetosphere here on Earth. So we're very interested to understand more about that.

And we'll be using the magnetometer to measure the magnetic field and to add to our knowledge. It will help us to understand more about the magnetic field here on Earth as well. So we'll be doing all of that. There's lots more instruments, 10 instruments altogether on JUICE. There's radar to penetrate the surface. There's a laser altimeter that's going to measure the sort of tidal stretching and relaxing of the moons that Jupiter's gravitational pull causes. And this is interesting because this stretching and squeezing can cause tectonic activity. And that generates heat, much as if you took a ball of clay and you needed it, you'd find it heated up. And so where there's heat energy, that might provide the energy

required for life. We said it's a long trip. What are the challenges of sending a mission towards Jupiter? Well, that's a very good question. It is very challenging. The long distance means you have to have a huge solar array to power the spacecraft for all that long time cruising towards Jupiter and to keep the instruments active when we get there. So that solar array, I think it's about 85 square metres, will have to be folded up inside the rocket launcher and then it will have to be deployed in space. So that's a challenge. It's going to have to be really autonomous when it gets there. It's going to take a very long time for command signals from the ground

to reach the spacecraft. And some of the time it's going to be out of communication. So it's really going to have to look after itself a lot of the time. It's going to have to be very reliable. It's going to have to cope with a lot of radiation around Jupiter. All of the instruments on board have had to be shielded or radiation hardened so that they can cope with that environment. There's been a lot of testing on the ground to make sure that's going to work. And actually, before you can launch anything into space, you have to test to make sure it can withstand the shock of launch. And then it's not just the radiation in space, it's the temperature

extremes. And of course, it's a vacuum. So there's been a lot of testing on various models of JUICE leading up to the eventual flight model that will be launched and will go and take the instruments leading up to the eventual flight model that will be launched and will go and take the instruments to do their stuff. So a lot of challenges, a lot of challenges. Yeah, and so what can a mission like this tell us about our solar system? You know, if we're exploring these three moons, these icy worlds, what else can that reveal? It's a sort of a mini model of the solar system as a whole. We call them

moons because they're orbiting a planet, but they are bigger than Mercury, much, much bigger than our moons. So they sort of mimic what's going on in the solar system as a whole. So the more we can understand about the Jupiter system, the more we'll understand about our solar system as well. What can it tell us looking at Jupiter and its moons and the way they tug on each other because of their gravity? That's going to show us how the sun and planets interact in that way. We can use the fact that Ganymede's magnetosphere interacts with Jupiter's to know a little bit more about how the Earth and the sun interact.

So it's a sort of a mini model of the solar system. And we can do an awful lot of physics that will help us to understand more about the solar system as a whole. And, you know, we've said this is a challenging mission in itself. But what do you think the future holds for exploring other icy worlds further, or even these same ones? What's going to happen in the future? Well, there's an awful lot of interest. As I say, these icy moons are one of the most exciting things we can possibly look at in the solar system and beyond

because of the potential habitability. And certainly the James Webb Space Telescope, which is NASA's next big observatory following in the footsteps of Hubble, that's going to be launched this december yes we're very excited for it on the super massive podcast and i am yes very excited we've done a lot of work um the uk is led on one of the instruments on james webb so i've been very closely connected with it and i'm really looking forward to it to it launching one of the things that web Webb will do is observe Europa and another

icy moon, this time of Saturn, Enceladus, because both of them, we think, are producing plumes of possibly water vapor that are shooting up through cracks in the ice hundreds of kilometers up. And in 2008, the Cassini mission was able to fly through the plumes on Enceladus and analyze them. And we'd like very much to get more information about that and to do the same thing on Europa. And then after that, NASA plans to launch Europa Clipper in the next few years. And this will go back to Europa again and study it much as JUICE is going to look at Ganymede and for very similar reasons. And then finally, in the future, there might be a joint ESA-NASA mission to the ice giants, Uranus and Neptune, and their icy moons. Because the more we learn, the more questions we're going

to have. And really, this is just a very exciting time to be someone who's studying and exploring icy moons. This is the Supermassive Podcast from the Royal Astronomical Society with me, astrophysicist Dr Becky Smethurst and science journalist extraordinaire Izzy Clark. That's me. This month we're exploring the coolest worlds in our solar system and the questions from listeners have been rolling in. So Becky, Robert, get ready. I'm limbering up, I'm limbering up. Let's start with this question from NZC Meow. I think I've got that name right. Apologies if that's not correct. They ask, can there be an icy world close to a star? Venus is hotter than Mercury, even though it's further from the sun. So could a planet be colder than its neighbour,

but closer to their star? Yeah, you can get planets hotter at greater distances because of atmosphere. And that's what happens in the case of Venus and Mercury. Venus is hotter because it has this thick carbon dioxide atmosphere that traps energy in this runaway greenhouse effect, heating it more than Mercury, where the surface of Mercury is just fried by the sun, right?

And it reflects a lot of sun's energy back out into space. So it doesn't really heat up the same as Venus does and just store heat in that way. So it's also responsible for Venus and Mercury giving you different hotter stars at different distance. But in terms of getting an icy world close to a star, theoretically, yes, you can, right? You could have an icy world close to a star perhaps if it's not as hot as the sun maybe like a brown or red dwarf that's you know it's still like 3000 kelvin but it's not the 5000 odd kelvin of the sun right it's an astronomer's cool and in fact there is actually a planet called gliese 436b and it's orbiting a red dwarf about 22 times closer than mercury and it's about the same size

as neptune and it's dubbed a hot ice world okay which is really weird right yeah hot ice it sounds so strange so we think it has a sort of like steamy water you know like water vapor and hydrogen atmosphere surrounding it because you know it's very big to that, but it's just very close to its star. So close to the surface would be, you know, very steamy, almost. But the thing is, the pressure is then you get lower in the atmosphere would mean that, you know, if there is a lot of water there, it will turn to ice, even if it's really hot, because it's really close to the star. So whether water is a liquid or a solid or a gas, it doesn't just depend on temperature, right? It depends on pressure as well. So think about like when you go up in altitude, right?

Say you're going on a holiday, you're going to the mountains, maybe you're going skiing, right? Your kettle, your tea, boils quicker at higher altitudes because the pressure is lower, right? It doesn't boil at 100 degrees C. It boils slightly less the temperature like 96 something like that depending on how high up you are so it's sort of like the reverse of that that's happening in this atmosphere right is that even though it's really hot the pressure is so high that you'll still get ice rather than liquid water or a gas and so that's how you can get a hot ice world really close to a star i love that thank you so much for answering that one

robert we've got this one from anita rag who wants to know we don't know much about icy worlds like neptune and uranus but what information do you think the james webb space telescope could give us about these planets well i'm going to struggle to answer becky's baked alaska answer to that planet but um but uh yeah, the Webb telescope, the James Webb telescope about to launch, you know, very, very soon, hopefully by the end of this year, it'll be up and running

and we'll start to answer these questions. And the big difference is that the James Webb telescope will have a much bigger mirror than Hubble, about six and a half meters across if it unfolds successfully. So to deliver sharper images to begin with, it's also operating in mid-infrared. So it's looking at the universe in a different way. And it'll also be doing things

like spectroscopy, so splitting the life from objects to understand what they're made of. And those things together will help us study Uranus and Neptune. Now, we're not going to see any probes there for decades. They're just so far away. It's so expensive. I think one will arrive by the time I'm 80. So I'm not holding my breath to see these results in great detail, or at least probably not while I'm still working anyway. But with that bigger telescope in orbit, we can look at them. It's part of the program. We can see the weather patterns because now there are no space missions. That's what we do. We look at these distant worlds with telescopes like Hubble and then James Webb Telescope. We can see the weather changing, see if there's anything like any more dark spots

that were around the famous great dark spot that Voyager saw back in 1989. And we can analyze the composition of the atmospheres because that's what a spectroscope can do. It can look for the chemicals in there and we can understand things like the mysteries of these planets. Uranus has winds, I think, 560 miles an hour

and Neptune has some extraordinarily fast winds. I think 1,500 miles an hour, and Neptune has some extraordinarily fast winds. I think 1,500 miles an hour is the record they clock. It's a very, very, very windy place. So those kind of things are the sort of things that Webb Telescope will answer. And one of the other odd things is that Uranus and Neptune, although they're quite similar, there are some distinct differences. And one really weird thing is thatune gives off more heat than it receives in the sun but uranus doesn't so although neptune is much further from the sun the top of the atmosphere is a similar temperature to uranus that's really not well understood why that's happening there are really intriguing things going on as well in some of the models i mean some researchers have suggested that there might be

diamonds sinking down through the deeper bit of the atmosphere for example which i think is another science fiction premise actually diamond miners on your love that yes please we can definitely go for that one can't we so so there are lots of mysteries in these two these two planets and the james webb telescope is certainly going to be a big part of understanding more it's actually a uk scientist lee fletcher in leicester who's leading this work yeah and and sticking with these two outer planets, Becky, Timo asks, why haven't we had a mission to Neptune and Uranus since voyagers flew by them? I think everyone wants to know the answer to that. And how are the conditions at the cores of those two outermost planets and what are they made of? Well, it's not for lack of trying, Teemo. Let me tell you,

in terms of missions to Neptune and Uranus, the people who study Neptune and Uranus are desperate, for want of a better word, right? We know so little about them except for that brief glimpse that Voyager gave us. And like most pursuits in science, it left us with more questions than answers. And hopefully the James Webb will go some way to answering a couple couple of those but will probably also give us more questions as well especially because i mean uranus spins on its side it's the weirdest planet in our solar system

right it's more than 90 degrees different in terms of its axis compared to how the sun spins so it's magnetic field and aurora and incredibly weird those are things that we already don't understand very well on other planets either so you know getting it at Neptune and Uranus would be a dream, I think, for a lot of people. The problem is their distance. And remember when Voyager was launched, it was when the outer planets of Jupiter, Saturn, Uranus, Neptune, they were all not aligned, but they were roughly in a line so that they were at least in the same direction going into space, which is not always true for those planets that are very, very far away. So we'd have to send separate missions to Neptune and Uranus if we were going to do it now. They're in the works for maybe 2030,

but there's only so much money we can spend on these kinds of missions. And they get a lot of competition from missions exploring mirror planets like Mars, as we've seen a lot of in recent years and obviously Venus is is getting up there now after that phosphine discovery too last year and obviously these potentially habitable icy worlds as well of the moons of Jupiter and Saturn are sort of winning out against a Uranus and Neptune mission at the minute and they get chosen for funding instead so that's mainly the reason as for the cause timo you're listening to tune we think they're very similar to our own to honest of earth they're mostly iron and a bit of rock right we think that all bodies in the solar system formed

in this hierarchical way of clumping together bits of rock which as they started to then get heavier they would attract the much lighter gases around them and that would build up the gas giants. Of course, sending a mission there, what else is no? A lot more. So I mean, if any of the panels of NASA and ESA are listening right now, know that my vote is for a year to submit.

Yeah, we'll see what we can do. Well, thank you to everyone that sent in questions. And if you want to send in one of your own for a future episode, then email podcast at ras.ac.uk or tweet at Royal Astro Sock. And I just want to note that if these past two episodes have piqued your interest, then there's a new book by Natalie Starkey called Fire and Ice, the volcanoes of the solar system. So pretty perfect for what we've been talking about recently um but we will bring back book club next month so ready your science books for that one i have to make a quick

plug for one i was sent as well which is a voyager a photo album mainly because it's been in my my study here i think for a while but it's fun um you know the voyager missions were such a long time ago but the images are still fantastic and they are the only images we have of the uranus and neptune only close-up one so it's just called voyager photographs from humanity's greatest But the images are still fantastic. And they are the only images we have of Uranus and Neptune, only close up ones. So it's just called Voyager, photographs from humanity's greatest journey. And I think it's great.

It's huge. Like listeners can't obviously see this, but it's like this massive white book with a big gold print on the front that's like Voyager. Like, yes, okay. I get it. I want that. Christmas like. Exactly.

So Robert, what can we see in the night sky this month? Well, it's really appropriate that we've been talking about ice giants, Uranus and Neptune, and icy moons, because all of them are actually quite well placed in the sky from the UK at the moment. So we've still got Jupiter and Saturn down in the southern sky. They're getting a little easier to see in terms of being an antisocial diamond knight. They're actually there in the early evening sky now as well they're very obvious very bright just on the southern horizon and you get sort of saturn first then jupiter further to the left and those those planets obviously you can actually see europa fairly easily with a pair of binoculars

orbiting around jupiter and then celadus with a reasonable telescope going around Saturn so if you want to see these icy moons at least as glints of light you can do that and further on in the sky a bit later in the night you've got Uranus and Neptune too and Neptune is in Aquarius and that means it's going to be rising slightly you know mid-evening onwards best place around midnight and 1am still on summertime and Uranus a bit after that. So it's a really good time to see all these worlds we've been describing. Now, I should stress that Neptune and Uranus, they look really tiny. If you've got a pair of binoculars, you need a pair of binoculars to see them at all. And you'll probably just see them as a star-like point. And if you really want to be a sort of classical astronomer, what you can do is look

at the part of the sky where they are, the various finder charts online, look at them one night and then look at them the next and plot them moving across compared with the other stars. That's quite a nice way to find them too. I should also say we're actually running a live event completely coincidentally, which is called something like Finding Out More About Uranus, and that'll be run from the 8th to the 10th of October.

The RAS is doing that. We'll have details on our website. We'll plug it on Twitter and so on. And that will be where we're connecting to UK astronomers. Some of it will be in the UK and some will be running the telescopes on Mount Akekea in Hawaii,

looking at Uranus and hopefully trying to answer some of the questions we've been talking about. I think I'll probably join that one rather than try and set up my own, like, oh oh god it's not working again oh yeah we need we need telescope surgery for you busy we need to tell us and to

move out of london yeah i know tell me about it but all i want yeah all i want to say as well is that they are going to try and do things like see if they can detect the aurora on uranus they're not promising because it's difficult but they're going to give that a shot and then obviously beyond that you know it's the autumn sky you can see things like the Andromeda galaxy the furthest object visible to the unaided eye get a nice find a chart near the square of Pegasus in the eastern sky as the night goes on so there's a lot going on and you know go out and enjoy it and can we shout out to Rohi in India who sent us a brilliant photo of Venus and the crescent moon last month. And so we love to see your astronomy photos. So do keep them coming.

And Becky, you're hoping to make some observations this week. Is that happening? What can you tell us? Yeah, so I have time on the Isaac Newton telescope in La Palma from Wednesday to Sunday this week. But those of you who have been watching the news will have noticed that La Palma is currently under a state of emergency after the volcano there erupted for the first time in 50 years um so our observations are a little bit up

in the air at the moment mainly because because obviously the flights, everyone will know, volcanic ash and flights don't pair well together. So the airport on the island has been closed. But there is a big impact for volcanic ash on observing as well that people might not know about. So volcanic ash is fine particles of rock. It's not soft and fluffy ash like you would get from, say, a fire. Maybe people are lighting fires as we get into autumn now. from say, you know, a fire, you know, maybe people are lighting fires as we get into autumn now. It's hard and it's abrasive. So telescope domes and telescope drivers for pointing, they're all moving parts, right? It's a lot of moving parts. If you get ash in there, it can do a lot of damage. Ash is also bad for electronics as well. It can block vents and jam cooling fans. So the equipment overheats and it can short circuit things as well because it's

rock. So it contains a lot of metal. Even keyboards on computers are at risk, right? cooling fans so the equipment overheats and it can short circuit things as well because it's rock so it contains a bit of metal even keyboards on computers are at risk right so opening the dome at all is basically a no-go when there is any risk of volcanic ash in the air the obvious other thing as well is that what really scuppers astronomical observations even if you probably could open the telescopes because there was nothing low down if there's ash high up in the atmosphere there's honestly no point opening the dome observatories are built you know away from light pollution but also high up because then the air is less humid it's thinner there's less atmospheric disturbance and turbulence right that's going to disturb the light on its way through the atmosphere to the

telescope right we all talk about twinkle twinkle little star when we're kids that's going to disturb the light on its way to the atmosphere to the telescope, right? We all talk about twinkle, twinkle, little star when we're kids. That's an astronomer's worst nightmare. You want no twinkle at all, right? If it's twinkling, your pictures are going to be so blurry and tiny ash particles only increase the twinkle. She's destroying the romance of the night sky in a single sentence. Yeah. destroying the romance of the night sky in a single sentence.

Not only are we ruining everyone's favourite science fiction films, we've moved on to nursery rhymes. My goodness. Twinkle, twinkle, little star, how annoying you are. They might be persuaded to sing that. Oh, well, fingers crossed. Third time lucky? Yeah, maybe. Well, I think that is it for this month next month we're finally getting to it jwst the james webb space telescope

wait i can't wait yeah i mean it was supposed to be october launch right it's been pushed back to december but it's an official launch date an official launch date has been set previously it was sort of a targeted launch date but now it's in the diary it's not in pencil it's been written in pen and we're all very excited i mean i i made a documentary about the james goddard space telescope in 2018 for five live yeah i remember going to a conference and being told, you know, get thinking now what you want to propose for time on the James Webb Space Telescope because, you know,

early proposals have got to be in by 2017. Anyway, thank you again to the UK Space Agency for sponsoring this episode of the Supermassive Podcast. Please don't forget to follow and subscribe and even better, if you want to leave a review and tell the world why you love the show and please do that really helps us out until next time though happy stargazing