The Supermassive Podcast - 44: Here Comes the Sun...with NASA's Head of Science

Episode Date: August 28, 2023

This month, Izzie and Dr Becky are off to the Sun…Partly because the UK summer has been rubbish but mostly because there are a lot of things we still don’t know about our local star.  Joining them on their voyage is the Head of Science at NASA, Dr Nicola Fox, to explain the latest efforts to study the sun, the Project Scientist for Solar Orbiter, Dr Daniel Mueller, and Dr Robert Massey is on hand to answer your questions.  Watch ESA's Solar Orbiter video, featuring the Supermassive's editor Richard Hollingham. https://www.esa.int/ESA_Multimedia/Videos/2022/05/Solar_Orbiter_s_first_close_encounter The Supermassive Podcast is a Boffin Media Production by Izzie Clarke and Richard Hollingham.

Hello and welcome to the Supermassive podcast from the Royal Astronomical Society with me, science journalist Izzy Clark and astrophysicist Dr Becky Smethurst. This month we're off to the sun, partly because the UK summer has been rubbish so far, but mostly because there's a lot of things we still don't know about our local star. We'll hear from the head of science at nasa the head i know i'm so i was so excited uh that's dr nicola fox and that's all about the latest efforts to study the sun plus the project scientist for solar orbiter dr daniel muller tells us all about this remarkable mission i'm excited for those two but before that we need to celebrate the fact that we are millionaire. We've officially hit 1 million listens

across the Supermassive podcast series. So thank you so much to all of you for just listening to us natter on about space. I mean, we love making this podcast. So it's just great that there's someone out there listening to it, to be honest. Just a couple of nerds, you know, just sat in their houses chatting about space and somehow you all want to tune in. It's great. The Royal AstroSoc gave us some mics and here we are.

But enough self-congratulation. Let's get on with the episode. And with us, as ever, is Dr. Robert Massey, the Deputy Director of the Royal Astronomical Society. So, Robert, can you run us through the basics? What's the structure of the sun? a star and therefore you know like most stars it's big it's bigger than anything else in the solar system by far any single object anyway it spans more than 100 earths so you could stretch more than 100 earths across the diameter of the sun and you could fit 1.3 million earths inside just the obviously visible bit of the sun the bit that you know the glowing photosphere the brightest bit and it has more than 300 000 times the mass of the earth so what i'm saying in all is there's a lot of sun and it's made of nearly three quarters hydrogen just under a quarter helium and everything else all the other elements there all the things that were much more familiar on earth are just over one percent of that so it's quite unlike the rocky planets but

not so different to giant planets like jupiter and the sun that you shouldn't look at at all really i mean i do have to emphasize that every time we talk about the sun look you shouldn't look at at all, really. I mean, I do have to emphasise that every time we talk about the sun. Look at it only with great care. But it has a bright surface called the photosphere. That's the bit where 99% of the light comes from. Above that, you have layers that we only see during a total solar eclipse. Things like the, well, again, unless you're using special equipment or a space probe. But things like the chromosphere and the corona and so on.

Very hard to see without special equipment. And inside the sun is its powerhouse core. That's where the energy comes from that powers the sun and keeps it shining and stops it collapsing under the influence of gravity. And you've got a nuclear reactor in the centre, a giant nuclear fusion reactor turning hydrogen to helium. And then in layers above that, that resulting, that generated energy slowly seeps out. It's remarkable actually that it takes at least thousands of years to get out of the sun. I was trying to read around different papers on this.

As far as I could see, the debate was anywhere between 10,000 and a million years to escape the sun. Of course, a few orders of magnitude between astronomy and the moon. Exactly, yes, a classic astronomy debate. Two orders of magnitude, that's not too bad. Cheers, Robert. We'll catch up with you later in the show to take on some listener questions so as robert said the sun is the biggest object in our solar system the distance from the center

to the surface is 695 000 kilometers but in the grand scheme of space the sun's size is pretty average but it is our nearest star and we still don't understand many of the processes that drive it. So how are scientists studying the sun and how does that help us here on Earth? It's something that I asked Dr. Nicola Fox, Head of Science at NASA. Say that again, Izzy. Head of Science at NASA. But first, I just had to know what her job was like. But first, I just had to know what her job was like.

So as the head of science, I actually get to oversee over 140 missions in all different stages of their life. Some of them are still being designed and developed. And others, of course, are up in space taking great measurements for us. Even as old as our amazing Voyager spacecraft that are just about to celebrate their 46th birthday in space and still sending back groundbreaking data every time. And of course, the science we do, we cover everything from, you know, those amazing images that you see from the James Webb Space Telescope, looking at the far, far, far distant galaxies away to looking at tiny little structures, far distant galaxies away, to looking at tiny little structures and how genes respond to deep space by looking at how yeast and algae and fungi kind of adapt in deep space, to looking at all

aspects of our own planet and climate change, to studying every planet in our solar system, and of course, our very favorite star, the sun. I mean, you must be extremely busy. Are you allowed to have a favorite? Do you have a favorite? So I unashamedly do have a favorite. I love all of my missions completely. But the one closest to my heart is Parker Solar Probe. And that is because I worked on that mission as the project scientist for many, many, many years, from when it was just a PowerPoint charts to actually watching it launch in Florida. So that will always be my favorite mission.

What was that like having worked on that for so long to then see it launch? It was just the most amazing experience to see something. I mean, you're filled with joy as you see the launch happen, but you're also really sad because you're not going to see that spacecraft again. And you really do feel like the spacecraft becomes part of your team. So there's that sort of mix. And the thing that makes Parker Solar Probe so special was it was actually named for Dr. Eugene Parker. And it's the only NASA mission that's ever been named for somebody during their own lifetime. And so Dr. Parker Parker. And it's the only NASA mission that's ever been named for somebody during their own lifetime. And so Dr. Parker was with us at the launch. And so he's the only person that's

ever watched a mission bearing his name actually launch. So standing with him and sharing in his emotion, just does everything about the mission. It's steeped in history it was first proposed in 1958 finally launched in 2018 so there's a lot of history and firsts and you know just the whole mission was just great amazing gosh that must have been such an incredible moment if we go back to the very basics why do we study the sun what's the point point? Why is it important for us on Earth to have that understanding? So there's many reasons to study the sun. I mean, obviously, it's our neighbouring star. If that star was not there, we wouldn't be here. It's important that we understand our relationship with that star. It is a very active star. It does have solar storms, throws off

billions of tonnes of coronal material traveling at millions of miles an hour. If that impacts, happens to be directed towards the earth, we will feel the impacts of that storm. And so understanding, improving our ability to predict if this happens, this is what will happen here at earth. This is the impact it could have on our technology. But also, it is a star. We say it's just an average star, but it's the only star we know that actually supports life on a planet and allowing us to understand how a star works. I mean, even though it was very difficult to send Parker Solar Probe up close to the

star, it's still a lot easier to study that star than it is to study other stars in other stellar systems. So, you know, understanding just how the sun works, it tells us a lot about how a star works. And so, you know, as we want to obviously find planets in other systems that could sustain life, we need to really understand what's special or what is it about our star that allows it to sustain life here. So it helps us look for exoplanets and signatures of life in other stellar systems. And so when we look at the mechanics going on inside the star, you know, what are those key processes driving the sun? How is it powered? So it's powered by some, you by some very complicated nuclear

reactions that go on in the centre of the star that essentially allow it to put out obviously light, but it puts out a lot of energy. The actual atmosphere of the star protects us. So in the same way that we want to know if a big storm comes, how is our planet going to respond? The actual solar wind, so that atmosphere that continually streams away from the sun, forms a protective bubble, like a cavity for our whole solar system. So as we are orbiting around the Milky Way, our sun is actually protecting us from the vagaries of interstellar space and the things that we don't know, the things that are out there. There's a lot of processes that are going on. Most of it is like these sort of nuclear reactions,

but then there's these processes that cause the corona to be hotter than the surface of the sun, which is one of the mysteries that we wanted to go solve with Parker Solar Probe. Why, once it gets superheated there, why does it get accelerated so that it moves away, continually bathing all of the planets? So lots of processes still to study. Yeah. And so how are we currently sensing and what are we learning about our sun at the moment? So I think one of the things we were surprised at was the fact that there are very interesting processes going on further away from the sun than we thought. When Parker Solar Probe was designed, it does about 24 close flybys of the sun

and uses the planet Venus to do gravity assists. It will do seven in the full mission lifetime to gradually kind of walk closer and closer to the sun. And we thought we would really have to be towards the end of the mission to be kind of sensing some of the excitement, you know, to be getting into the action region where these processes that we didn't know what actual processes were happening. And yet we found very soon into the mission, really exciting features in the sun. And so features, particularly in the magnetic field,

where we saw the magnetic field kind of looping back on itself, forming like S shapes in the magnetic field, which require something to cause that twist to happen. It's like trying to twist a garden hose. It wants to keep springing back. So you actually have to, a process has to happen that causes this kink. And then as the kink relaxes, it's letting out energy in the form of heat, causing the heating of the solar wind. They were some of the surprises that we found already as we're getting closer and closer to the sun. Certainly now, so there's a region where the magnetic field is like one rigid body with

the sun. So everything is rotating together. And then you get to this place where the magnetic field is like one rigid body with the sun. So everything is rotating together. And then you get to this place where the magnetic field can escape and it no longer rotates with the sun. And we've gone below that region. And again, that boundary between these two sort of very different areas in the corona, when we dipped below that much earlier than we thought we would. in the corona when we dipped below that much earlier than we thought we would. So further away from the sun than we really thought we would be. So lots of really exciting things. More to come. We have two more Venus flybys. And in December of 2024, we will be closer than 10 solar radii away from the sun. Really, really excited about that.

10 solar radii away from the sun really really excited about that and how has this changed our understanding of our sun you know are we seeing it i don't excuse the pun in a new light you know is this then inspiring more missions and you're sort of more head scratching it's like okay right so now we've got this what are the other questions that we're now asking i suppose is what i'd like to know well so now we found features that we didn't know existed in the solar wind so these s shaped curves you know we're finding these features and now we have to explain what causes the features and so you know we didn't even know those features existed before we had the mission now we're working on okay here's three possible theories for what is causing these features. And then as you do more journeys through the sun, you know what you're looking for.

Let's look for those signatures. But you're right. The more we study, the more questions come up because you find things that you didn't expect and then you want to explain them. So I'm sure that even in the next year we will find more things that we need to to explain and for you what are those big sort of unanswered questions on solar mechanics and solar physics that you'd like to find out so I think that one of the things that's interesting for me is is's often sort of very different theories

behind what's causing the same phenomena. And I think we're going to find it's a mix of them, you know, and so it isn't going to be so sharply, it's only this or it's only this. And we're going to find that somehow these things are linked in a way that we didn't realize before. There's the camp that firmly believes everything is due to turbulence. And there is the camp that firmly believes everything is due to magnetic reconnection. And I think we're going to find it's due to that. What is next for Parker Solar Probe

and studying the sun? So for Parker Solar Probe, continuing to do another two Venus flybys and then being super close to the sun and just returning more and more amazing data for us to work on. As you know, next things for the sun, we have a lot of missions coming up. We have Punch, that is four spacecraft. They're about the size of a suitcase each. Three of them will sort of separate around and form like a wide angled camera. And the other one, the fourth one is sort of a narrow and that's going to be looking essentially at the region that Parker Solar Probe is flying through. So very close to the sun and almost almost looking at the sun from the inside out, like starting close to the sun and seeing how things change as they move away. And then we have Sunrise. that is six tiny CubeSats. They are going to launch, separate and sort of form

like one giant radio receiver in the sky. Will there be capacity, say for Punch and Sunrise to then join up with Parker Solar Probe so you can really strengthen that view and see the sun from lots of different aspects and different wavelengths as well? Oh, yes. So we use all of our solar missions. In fact, you know, we use all of the missions kind of as one big portfolio. We think of it like as one observatory.

So particularly with heliophysics, we look at everything close to the sun all the way out through, you know, how it impacts us here on Earth. And then with our Voyager spacecraft, actually, how the solar wind is changing that boundary between our solar neighborhood and interstellar space. So we kind of have all of those missions that do those roles. And so yes, absolutely, we look at putting together all of our solar fleet to be able to really help us illuminate the mysteries of the sun. Thank you so much to Nicola Fox, Head of Science at NASA. Becky, can we assume that the sun is like other stars? You know, what does it tell us about other stars? it tell us about other stars? Yeah, so we can now assume that thanks to centuries of science research, right? The history of sort of our perspective of what the sun was and whether the sun was another star is, I mean, quite fascinating. I mean, the first time that anybody

suggested it was way back in, you know, Greek philosopher sort of era. I don't know how you know how to pronounce this. I'm going to have a go. Everyone's going to laugh at me. Anaxagoras suggested it in 450 BC and then you've got the likes of Giordano Bruno in the 16th century who said you know the sun is a star and it's at the center of the solar system and he was you know burnt for heresy by the Catholic church because of just saying that the sun is like the stars that we see in the sky and it wasn't something special um and then of course you've then got that sort of train of science sort of results that came through that time of Kepler and Newton figuring out laws of gravity

and the motion of planets as well, to the point where, yeah, we then sort of accepted the fact that the planets were orbiting the sun. And then by 1838, you've got Friedrich Bessel, who calculated the distance to stars for the first time without assuming anything about stars. So it was a completely independent measure and it was using something called parallax. It's the idea that sort of as the Earth orbits the sun, our perspective on a star changes. And so we see it in a slightly different position. That sort of, you know, hold your finger out at arm's length in front of you and close one eye.

Close one eye. And see it shift about. It's the same thing, right? And so when you calculate those distances, they were absolutely huge. Way bigger than anybody had ever guessed or saw at or estimated at. And that meant that they were much brighter than first thought as well. Because they were, you know, absolute pinpricks, you you know on the sky in terms of how we see them and so that made them have brightnesses like the sun right okay and that was the point that people realized that yeah the sun is a star obviously the sun is a star

but not all stars are suns oh tell us more because the sun is a you know, a special type of star. It's what we call a G-type star. So there are a lot of stars more massive, brighter, bluer than the sun. And then there are also a lot of smaller, fainter, redder stars than the sun. And the light we get from all of these stars is very different. Yeah. But obviously starting out by studying the sun gives us then a base point for jumping off at you know but we do see sun-like stars out there that have the same sort of spectrum of light from them so it gives us the same sort of temperature and composition and stuff so alpha centauri a for example is also a g-type star very

similar to the sun so one of our closest stars right it's almost identical which not that surprising probably formed from the same material it's just got a few more heavier elements yeah stuff that makes up us that robert was talking about before there's trace sort of one percent ish it's got a little bit more so that's sort of interesting to think well the materials are there to form planets you know well that's what yeah that's what i was mulling over yeah exactly so you know it's interesting to think by comparing to what we know about the sun, you know, we can then get clues what conditions are like,

not just for that star, but also for maybe any potential planets around those stars as well. Well, yeah. So on that, you know, what can it tell us about the possibilities for other Earths out there? Can we say that was the big question.

You know, it's the big one. I think the biggest, right? There's obviously a big search for not just life on other planets out there, but specifically like the most Earth-like planet orbiting the most Sun-like star. Yeah, exactly. You know, and we've always been looking for that. And there's lots of variables that come into that. Age of the star is a big one.

Because, you know, if we think about life here on earth the earth and the sun have been around for four and a half five billion years and that's how long it's took for life like us to come around and we haven't been around for that long you know a tiny fraction of that four and a half billion years so if you have a sun-like star but it's a lot younger then you might think well life's probably not had enough time to even evolve to the level that we recognize life as, you know, in that time. At least complex life anyway, I think is what I'm talking about there. I think the closest one we've got in terms of most Earth-like planet around most Sun-like star is Kepler-452b, which you hear a lot of astronomers talk about. You know, the planet is

about one and a half times the diameter of the Earth, it's a lot denser so it's five times the mass of the earth but it does orbit its star at the same distance as earth does and the star is again a g-type star the same type as the sun it's got a similar temperature and it's around about six billion years old so it's not quite a twin necessarily but it's a definite sibling you know a slight distant cousin maybe yeah exactly and again so i mean people say you know you know if we're looking for life why are we always looking for earth like water and a sunlight star and it's like well it's because the only example we've got you know so it's probably the most likely place we'd find it again if we went looking so studying the sun and the solar system really tells us a lot about

other stars as well and their conditions so if you've got an object like that you know five times denser than earth how does that relationship to its star change because obviously we're kind of in that right as nicola said that right space in terms of distance as well so if you're more you're denser how does that change then with your distance to the star? Is that important? It's not really that important, no. Because we know that the distance to this planet is around about the same as Earth's distance from the sun.

So all it'll affect is actually how much the planet tugs on its own star. Right, okay. Which is helpful to us because it means we can more easily find it because the bigger the tug, the bigger the wobble of the star and we see that wobble on the sky.

The thing that it might have an effect on is the life that would form on the planet because obviously gravity is that much stronger with a five times heavier planet that's very dense as well so walking around like flatland or something i don't know you know it's all a lot don't maybe the life doesn't quite grow as tall on that planet okay if there is life there now the latest mission to the sun solar orbiter was launched by the european space agency in february 2020 and the mission set off to take the closest ever images of the sun observe the solar wind and the sun's polar regions like never before. And of course, to unravel the mysteries of the solar cycle. So three years on and we're well into the science

phase of the mission. So how's it getting on? I spoke with Dr. Daniel Muller, the project scientist for the mission who is responsible for Solar Orbiter's scientific observations. who is responsible for Solar Orbiter's scientific observations. Solar Orbiter is setting out to shed new light, in a way, on the Sun by observing the Sun from a distance with telescopes and spectrometers and at the same time measuring the solar wind as it whizzes past the spacecraft. But we have not been able to really connect it to its sources on the Sun. So that's what we're trying to do with Solar Orbiter. How can you get a spacecraft so near to the Sun without it, well, melting, essentially?

That's an excellent question. So the central piece of our spacecraft is a heat shield. So it is a mechanical structure to shield the spacecraft and in particular the sensitive instruments from the heat of the sun. So our maximum is around 12 times the solar radiation that you get at Earth's distance. So that's a lot of heat to get rid of. And the engineers devised a clever way of dealing with it. And so they designed a sort of sandwich-like heat shield, which is a little bit like a sandwich held together by toothpicks with the central layer removed.

It's in a way two different layers and nothing in between. And that nothing helps to get rid of the heat. So the first layer is being heated up and the heat is radiated sideways. And that achieves finally to get the temperature from about 500 degrees centigrade on the front side down to less than 50 degrees centigrade on the backside. And that is what we need to operate sensitive electronics. Okay. And so what's been involved in the science phase? Tell us, what have you found? What's been going on? Sure. So among the first things we found in the full

science phase, when we operated also the telescopes, were really small and super energetic bursts of energy in what we call the sun's corona. So the sun is a hot body, but at the surface, it is only around 6,000 degrees centigrade. But above that, it's a super hot and tenuous atmosphere that we call the corona. It's about a million degrees hot. And as we zoomed in, in spatial resolution, we saw lots of firecrackers going off all the time even in regions that we were calling quiet beforehand so that that was the first real key result from the full science mission and wow and were you surprised by that you know why why is that unexpected i suppose we were surprised to to see that amount of energy releases at small scales. And in a way, that's

not too surprising to be surprised, because when you go to the unexplored and you get higher resolution and you suddenly get a bigger telescope, you always see more things at smaller scales than before. But it might change the picture about how we think the corona is heated to these high temperatures. Because before, we weren't sure whether there would be enough energy in these small-scale events to potentially contribute to the heating of the entire atmosphere. And another question was always, why is it hot everywhere and not just in the regions that we see as being magnetically active around sunspots, for example?

So that was clearly a thing that was new and surprising. And the nice thing is also that once we knew where these things were happening, we could use also existing other missions that were just at slightly less high resolution to look for the same things and observe them in more complementary spectral channels with them. And so what is next for solar orbiter? What are those big questions that you still haven't got to the bottom of? We still have quite a long list of things that we want to do in the next few years, but we already have an

irresistible science case for a mission extension. And that revolves around the question of the sun's activity cycle, the solar cycle that varies in magnetic activity on a scale of 11 years. And just a few days ago, there was an X-class flare on the sun, and people are now revising their activity predictions for this solar cycle. It was expected to be a relatively modest activity compared to some other cycles about 20 years ago. But it looks like the sun is now being a lot more active than we thought it might be. And that is fundamentally still not fully understood.

And we hope we can help to understand it by flying out of the ecliptic and seeing the sun's polar region for the first time. Okay. And so all of this is grounded in this idea that the solar activity is changing. It's sort of going through this 11 year-ish cycle. You're looking at the equator at the moment but why are you interested in the poles what are you hoping they might be able to reveal the poles are key to understanding the sun's activity cycle so people have been developing models that can explain stellar activity cycles and the sun in particular by means of magnetized plasma in the interior of a star getting wound up due to the star's rotation.

And you can imagine that a little bit like spaghettis in the insides, but it is composed of magnetic field. And these spaghettis get tangled as you rotate. And the particular aspect is that the sun doesn't rotate like a solid body, but the parts of the equator rotate faster than the pole. And the bottom line is that everything gets tangled and eventually starts erupting onto the higher levels of the inner atmosphere and then produces sunspots at the surface. And so that's the origin of the sunspots. And then as a function of time,

these sunspots move. So new sunspots first emerge at higher latitudes and then in the end closer to the equator. And we believe or theoreticians believe that there's a sort of conveyor belt acting inside the sun that takes magnetic flux from the equator to the poles and back. And the only way to really test that is by observing the polar regions from a perspective where you can actually make line of sight measurements. And you can't do that from the ecliptic because everything at the pole is essentially seen edge on. So we can't really get a good handle of eruptions and magnetic fields at the poles. Daniel Muller, project scientist for Solar Orbiter. And if you get the opportunity, do have a look at the video of the sun from the mission on the ESA website.

And you might see, it's great, but you might see a familiar face or hear a familiar voice. That is Richard Hollingham, our editor um he's on that as well so nice yeah but it's such a good video put it in the link izzy yeah i'll put it i'll put it in the description you'll find it good on years this is the super massive podcast from the royal astronomical Society with me astrophysicist Dr Becky Sveathers and science journalist Izzy Clark. This month it's all about our sun but I'd like to take a slight detour via the moon please. We're recording this the day after India has made history with its Trans-Jayan 3 mission becoming the first to land in the lunar south Pole region. Well done, Israel. Well done.

I mean, it's huge. So, Robert, can I bring you back in here? The South Pole is notoriously difficult to land on. Why is that? Well, the Chandrayaan-3 is not quite at the South Pole, but it's still a long way south. It's about 78 degrees south, to be specific. So it actually landed in a relatively smooth region between the craters Bogolovsky and Manzinus. And if you look at the pictures of that part of the moon, you'll

see it's very, very heavily cratered. And that's why most of the Apollo missions, like Apollo 11 going to the Sea of Tranquility, didn't go there, but rather went to places that were flat lava planes because you've got more chance of finding a safe landing site. The other issue is that because the way the moon's axis is tilted with respect to the sun, it always has long shadows down there. So it's always really hard to find safe landing spots. And that makes it another challenge. You know, either even at local noon, I think you're still going to see shadows

and you're still not going to get the ease of finding a safe spot that you find nearer to the equator. So it's an impressive achievement. And it's worth noting that landers built by Russian, Japanese and Israeli teams have all failed in the last couple of years. And these were by no means untalented people. I mean, the Russian one was obviously only just last week. So that is an even more impressive achievement. And like Becky, you know, congratulations, Israel.

This is great. Doing that for $78 million as well is really quite simple. Budget. It's incredible so becky what is chandrian 3 going to be studying so yeah as robert was saying there's a lot of craters on the south pole of the moon which is why we're going there even if they're annoying to land near so these craters because they're so deep and because you're at the south pole they're in permanent shadow, the bottom of these craters, right? So that means that sunlight has never really touched them ever. So none of the chemistry that comes along with sunlight, you know, hitting molecules and, you know, breaking

them apart or whatever, none of that has happened down at the bottom of those craters. So you can think about, you know, what formed those craters was comets asteroids colliding with the moon in the very early days of the solar system and essentially whatever those comets left behind asteroids left behind is still there pristine fossilized in the bottom of these craters at the south pole amazing and one of the main things that we think should be there is water ice there's one of the main hypotheses for how the earth got all of its water is that there was no water here where the Earth and Moon formed. It was all out on the far reaches of the edge of the solar system and comets and asteroids brought it in, collided with the Earth and gave us our water. There's no way to test that on Earth, though, because we have weather and tectonic plates and it destroys all of the evidence.

It's very frustrating. Goodbye, evidence. But on the Moon, it's very frustrating but on the moon it's it's still there so finding water ice down there is exciting for two reasons the first one i'm like okay fine space exploration sure if you want to put a moon base on the moon and use that to go onwards to mars as is nasa's plan having water there on the moon is very useful because anybody that's been hiking and has had to take a litre or two litres of water with them knows how incredibly heavy water is. And if you have to launch water off the surface of the Earth to support astronauts on an extended mission, it makes launching that mission incredibly expensive in terms of fuel. on an extended mission it makes launching that mission incredibly expensive in terms of fuel but also anyone who's seen the martian knows you can split apart water into hydrogen and oxygen

and hydrogen you make rocket fuel so again you've got if you've got a source of water you can support astronauts you've got a source of rocket fuel for launching any missions off the moon so that's one reason why people are excited and why we need to find out how much water is actually there if any yeah as we expect it to be the second reason is it's this perfect fossil for what actually happened and people will look again how much water is there try and relate that to how much water were comets capable of bringing to the earth moon system you can do all sorts of like radioactive dating of the rocks as well to work out you know when exactly were they deposited there so you can not only get like a timeline and how much water got there and all that kind of stuff to really flesh out this hypothesis of where did earth's water come from

which is obviously dead important for life starting on earth as well yeah so a big old investigative mission how exciting yeah it's very exciting that's why i was so i was so thrilled when it landed in touchdown safety because as Robert said, the Russian one failed earlier in the week. It wasn't a guarantee and we were all just rooting for them that this one would succeed because of the amazing science that can come out of it. I know, and to join that legacy of space organisations

that have made it to the moon, what a huge achievement. Okay, so let's get on to some questions about the sun. Robert, can you start with this one? Richard Morris on Instagram asks, what I've always wanted to know is, which part of the Milky Way did the sun originate from? Well, Richard, if we wanted to be really specific, it's something we can never quite know.

And part of the reason is that we're certain the sun formed in the Milky Way. We're pretty sure it would have formed at the same distance it is from the centre of the galaxy as it is now. And it's probably formed in a cloud of gas that's moving in a similar, or was moving in a similar orbit to the one the sun has, taking about 230 million years to go around. But since that time, the sun is 4.6 billion years old, it's made about 20 of those orbits around the galaxy. And given that there are hundreds of billions of other stars all moving around the galaxy too, actually at slightly different speeds, it's pretty much impossible to say how the galaxy

was configured and where the Sun was within it at that time, even though we know it would have had a similar shape and so on. But there are people trying to look at at least the sort of environment it formed in and what stage of this cloud of gas and dust, the life of that the sun formed in. And I came across this European Research Council grant. It's amazing when you look these things up, you say, oh, somebody's actually trying to find this out by an astronomer called Maria Lagouro at Kalkoli Observatory in Hungary. She's using radioactive dating, so another form of that,

to try to understand whether the cloud where the sun claimed to life. But to answer the very specific question would be pretty much impossible. But we know it's definitely the Milky Way. It's unlikely to have gone through any radical changes of position since it formed. Right. OK, thanks for that. Becky, UK Space Chris has a question and that is, what are the odds of solar weather affecting technology, civilization, and life on Earth? Pretty, I mean, pretty high, I think. Like, if the sun has a solar flare and it impacts Earth,

it will affect technology. So the question is just if the sun has a strong enough solar flare and if it does hit us, right? So the most intense solar storm in history is known as the Carrington event, and that was back in 1859. And the aurora, like the northern lights, southern lights during that event were seen as far south as like Mexico and Hawaii. Oh, wow. Okay. Yeah.

There was failures of like telegraph systems. You didn't communicate with telegraphs back then. With pylons sparking, causing fires all over the place. And there's actually records of telegraph messages being sent between stations when the stations are just completely, you know, they had no power, they completely unplugged from batteries. And they were powering themselves based on the current that the aurora were inducing. Wow. Because the aurora were so incredibly strong so if we think about how much of an impact it had back then what 160 years ago is that quick maths yeah um and we apply that to

what could happen today electrical grids would completely fail so we'd all be without power communications that go long distances so particularly those that go up and out the atmosphere and back down again so things like airplane communications and you know cargo ships in remote locations on the sea all that would fail global navigation systems probably go down um there'd be satellites damaged as well probably from solar flares so that could be anything from weather to tv to whatever it might be and again gps and then also people think migrating animals might be affected too the ones that actually use magnetic fields to to migrate so things like birds honeybees that kind of thing would also be

affected for a number of days and that could um set them off so some pretty big impacts in terms of you know life here on earth in general i mean i would say so yes yeah which is why we're always watching and monitoring the sun for this kind of stuff so there was actually back in 2012 a carrington level event but it just missed earth right so these things happen it's just whether we happen to be in the sort of direct firing line if you will became very close and at the minute we are sort of on our way out of a lull in the solar cycle yeah so the sun has this cycle of like 11 years where it dips in activity and then rises again where you get more sunspots and more solar flares and less sunspots and less solar flares so we're coming into a region of more

activity which is great if you like to hunt aurora because it's stronger aurora which is going to be great but also it could mean maybe stronger solar flares as well that you know could have this impact i found a stat it was from the us but they estimated that if there was a carrington like event today the damage to the us in terms of like financial damage yeah would be between 600 billion and 3 trillion dollars. Wow. Well, that's immediately what sprang to mind is like, well, if that Carrington event had happened in today's society, what impact would that have? And I mean, well, that just goes to show a significant one. I should add in one thing, actually, because I did some work on this a long time ago. And one nice connection with the RAS is that we've got the original drawing by Richard Carrington of the flare on the sun.

So if you look in the library, you'll see that the copy of Monthly Notices has a picture of the flare and the large sunspot group. And so he saw that, saw this incredibly bright spot. So then a couple of days later, you had the big geomagnetic storm. So we should have a little bit of warning from the amount of monitoring that we're doing. You'd think so, wouldn't you? Yeah. Well, you do sort of have three days, but it's not. It just depends on whether it flips away or not, or suddenly decides to come towards us.

But it doesn't decide. The laws of physics direct it towards us. I'm not implying sentience here. But yeah, the other thing about it was I was on this working group trying to talk about what people thought we should do about it and uh yeah the apparently coastal areas in the uk are the ones most at risk so so bear that in mind if you live near the coast for some reason connected with the geology of the uk we're less at risk than the us and canada apparently interesting i'm really curious now why that is oh anyway it's a cheery note well i bet you bonus episode they'll just be like, excuse me.

If anyone else is intrigued as I am, please send in a question so that Robert can answer it in a future bonus episode. Yeah. Then I might defer it. We need a guest expert. Yeah. Okay. So we've got a question here that doesn't have a name on it, but Robert, can you help? The question is, why does the sun have sunspots and what can we learn from them?

Okay. So it is a good question. Why does the sun have sunspots and what can we learn from them? Okay, so it is a good question. And in a sunspot, what's happening is that you've got very concentrated magnetic fields preventing energy from inside the sun from reaching the surface as much at least. And so the spot is about 1,500 degrees, say, cooler, 1,500 Celsius cooler than the surrounding surface. And for that reason, they appear darker. But intriguingly, if you took a sunspot off the sun, which clearly you can't do, but if you put it in the night sky, it would be as bright as the full moon, which I thought was a fascinating point about just how bright they actually are.

But obviously, if you put even something very, very bright in front of the sun, it looks dark. And they're obviously interesting in their own right. But they're also a barometer for solar activity and output, the stuff that Becky was talking about. And the number of sunspots varies over this cycle she referred to. So a cycle of really 11 years up and down, but 22 years if you count the fact that the magnetic fields flip from north to south and then south to north. Now, so when solar output is higher, though, you do, as Becky was describing, see more space weather events and more northern lights. And the spots are, they form at high latitudes, so high up towards the north and south of the sun early in the cycle.

And then as new ones come, they get closer to the equator. And we think that reflects what's happening with the solar magnetic field. Now, it's very difficult to describe in audio terms, but if you imagine a very smooth north-south magnetic field lines on the sun, and then the sun rotating, it does it in a very, well, in perhaps a counterintuitive way. The equator of the sun actually then the sun rotating it does it in a very well in a perhaps a counterintuitive way the equator of the sun actually rotates more quickly than the poles and those lines curve around and stretch and eventually metaphor might be elastic bands they

all twist up and tangle and that tangling behavior leads to more spots and eventually what happens is that the the whole process resets the field flips from north to south or south to north, and we get a new cycle of them. And if we look at the spots themselves, with the best telescopes and space probes, which I strongly recommend you look at pictures online, they're incredible, from Solar Orbiter and other missions like that, Solar Dynamic Observatory and so on,

you see amazing detail, right down to these sort of cells of gas rising and falling around them. And although they might not look like much when you look at them with, say, a small telescope, and for goodness sake, as ever, recommend you only ever do that with a safe filter, and they look like these small dots, it's worth reflecting on the fact that very many of those are bigger than the Earth. Even the smaller ones tend to be about the size of the Earth. And we've known about them as a result

for about 3,000 years, and the first records are probably about 800 BC by Chinese and Korean astronomers. And what they must have been doing is seeing the sun at sunset, and it must have been hazy enough that they saw these dark markings on them. Now, I don't recommend anybody does that whatsoever, and it's really not a recommended way to try and look at the sun, because you just don't know when the sky will clear, and then you suddenly get a big blast of sunlight, and it is bad for your eyes. But it's intriguing that we've known about them for that long.

And then they were obviously drawn by people like Thomas Harriot and Galileo and so on after the invention of the telescope more than 400 years ago now so that is a quick potted description of sunspots it's a massive field of research there's plenty of other stuff to look around on it as well amazing okay thank you I'm Becky Mahanath Rudai asks how does the sun's magnetic field interact with the planetary magnetic fields? I've got to be honest, electromagnetism, not my favorite topic in physics. Come on, Becky, buckle up. You tested me, Mahanath. So the sun's magnetic field hugely impacts the planets, right? So it extends way beyond Neptune's orbit, the sun's magnetic field. It's absolutely huge. And it shapes all of the planet's magnetospheres. So that's essentially

the region around a planet where the planet's magnetic field does dominate. And if you look at diagrams of this, essentially what happens is the magnetic field gets compressed on the day side of a planet, so the side facing the sun, and then it like streams out in this huge tail on the night side of the planet, you know, facing away from the sun. So for Earth, for example, the magnetic field on the day side facing the sun goes to about six to ten times the Earth's radius, whereas on the night side it extends out to a thousand times the Earth's radius, whereas on the night side, it extends out to a thousand times the Earth's radius.

Wow, okay. So quite a large tail, yeah. Yeah, so a huge amount. So there's a lot of interaction there in terms of shaping it. And then that obviously gives us the aurora as well. And you see aurora not just on Earth, but also on Jupiter, for example,

and on Saturn as well, Neptune. I think we've seen some on Neptune and Uranus as well, but maybe don't quote me on that. I definitely know Jupiter and Saturn because that's some of my favorite images to look at ever. Okay, well, there we go. And so if you want to send in a question, then please do so. You can email podcast at ras.ac.uk, tweet at Royal Astro Sock, or find us on Instagram at Supermassive Pod. And so Robert, what can we see in the night sky over the next few weeks? Well, we're moving into what can be described as meteorological autumn in the Northern Hemisphere, or if you prefer, meteorological spring in the Southern Hemisphere. And that means for us up in the North, it starts to get dark that

much earlier, which is at least a bit more convenient if you want to go look at the sky and the equinox is on the 23rd of september but we do still keep some of the nicer stars of summer for a while longer so the milky way is the obvious still the standout feature if you've got a clear sky and there's nights are longer and the sun is a bit below further below the horizon that helps it makes it means that the view up in places with northern attitudes like the uk northern europe and Canada and so on, it's standing out a bit more against the background sky. And around the middle of the month when the moon is new is the best time to look for that. And we also start to see some of the first constellations of autumn. So if you look towards the east, so if you're in the northern hemisphere,

that means to the left of the Milky Way, then you start to see constellations like Pegasus, the winged horse, and the square of Pegasus that oddly, the name it shares with Andromeda and that looks like four big four brightish not spectacularly bright but brightish stars in a square shape there's a surprise there but far fewer within it so it really was an obvious grouping in the autumn sky and underneath that is the not very obvious constellation of Aquarius where Saturn is at the moment I highly recommend looking at that for now it's still pretty much at its best this year and it won't, you know, the next chance after this will get, I guess, the autumn of 2024. So do look at it over the next few months. And then

further east, if you're very patient and you stay up till 9.30 or so, then you can see Jupiter as well. So, and that's pretty much at its best from November, but we're starting to get a hint of it now unless you're prepared to stay up really late at night. But the big possible surprise this month is a newly discovered comet, and it's called C2023P1, brackets Nishimura, and it was found by the Japanese amateur astronomer Hideo Nishimura on the 11th of August, and it might be visible to the naked eye in the east in the dawn sky, which means around 5.30 in the morning, I'm sorry to say, near Venus, and to begin with the crescent moon from about between roughly about the 10th to the 18th of September, depends on how bright it gets. So do look out for that. So you do have to get up early

in the morning, I'm afraid, and probably need a pretty good eastern horizon and a relatively dark sky as well. So the middle of the month will be best for that reason too. But a pair of binoculars will help you find it, even if it's supposed to be visible to the eye. So do use that because quite often comets, although they have a quoted magnitude, say we measure things, astronomers measure things in terms of magnitude, brightness, and oddly higher numbers are fainter. It's about something between magnitude three and five. If it's at the higher end of that, that means it's fainter and it'll be a challenge to see with the eye. So do try a pair of binoculars. And you also need to remember this quote from the quite well established cometary observer david levy and he said comets are like cats they have tails and they do precisely

what they want but i will still try and see it absolutely should one of my favorite tips for comets is just like a long exposure shot on your phone just prop it up and take like a 10 second night mode shot and you'll be amazed at how much just sort of like this fuzz will just come out in that shot and then you'll be able to use it as like a little personal star chart map to be like where is it and then you go oh yeah i can see it i mean to be fair 5 30 a.m is ungodly early well no it's better than comet neo wise i got to think at two in the morning drove to our local park where there aren't too many streetlights and i literally had my telescope maybe about two weeks it was like really early days and just the cold was a lot

did you see it yeah i did it was amazing yeah So totally worth it. 5.30, that's fine. That's far more acceptable. Okay, so on that, I think that's it for this month. We'll be back in a few weeks' time with another bonus episode answering your questions. And then after that,

we're continuing to explore the gas giants with the planet Uranus. You won't find out if we've actually detected aurora on Uranus or if I was talking absolute rubbish. And obviously tweet us if you try some astronomy at home. It's at Royal Astrosoc on Twitter, or you can email your questions to podcast at ras.ac.uk, and we'll try and cover them in a future episode.

So until next time, everybody, happy stargazing.