The Supermassive Podcast - Supermassive Q and A...Live!

Episode Date: August 26, 2025

We are live at the National Astronomy Meeting in Durham with questions on everything from white holes and fuzzy stars, to solar storms and time travel. Science journalist Izzie Clarke is joined by Dr Ziri Younsi – part of the team that took the first picture of a black hole. Also on the panel, Jim Wild, Professor of Space Physics at Lancaster University and president-elect of the Royal Astronomical Society…and the one and only Dr Robert Massey, Deputy Director of the Royal Astronomical Society.  Join The Supermassive Club for ad-free listening and share your questions, images and more. Or email them to [e-mail] or on Instagram @SupermassivePod.The Supermassive Podcast is a Boffin Media production. The producers are Izzie Clarke and Richard Hollingham. Hosted on Acast. See acast.com/privacy for more information.

Hello and welcome to the supermassive podcast from the Royal Astronomical Society with me, science journalist Izzy Clark, live from the UK's national astronomy meeting in the beautiful city of Durham. Now, this is very exciting because normally myself and Dr Becky are just sat in our home office. kind of just like mooching around like, oh, what you've been up to? And now, but today we actually have actual people in front of us. We have our audience here, and I've got this in the script, where the cream of the astronomy community meet.

So that's what you guys are. But here with me today are some lovely guests as well. We have Dr. Ziri Yunzi, lecturer in general relativistic astrophysics at UCL. Jim Wilde, Professor of Space Physics at Lancaster University and President-elect of the Royal Astronomical Society. Yeah, and obviously the one and only Dr. Robert Massey, deputy director of the Royal Astronomical Society. So, Robert, Becky can't join us.

So you're okay to take the really, really, really hard questions. Yeah, I mean, we often write about how IP in particular, squirm when I get certain questions. And I'll be doing that live and visually as well. It's the line where we say, this is a good question. Exactly. This is a hard question. The pause for breath.

They're kind of chewing over the topic and then, yeah, we get that. Yes. So we will be taking audience questions. So get pondering, get thinking, we're ready to take. Well, I'm not ready to take them. I will facilitate the conversation. But Zeri, let's start with you. So I'd love to talk about what you work on.

So you worked on the first ever image of a black hole. So what was that like? Well, it was really, really cool. I think that's obvious. It was really exciting. It was a great opportunity for me to get into that really cutting-edge area of research very early on in my career. So actually, I joined the collaboration just after I finished my PhD, and it was this collaboration called the Event Horizon Telescope.

It had just been formed in around 2014, and then it was official in 2016. We actually recorded the data from these two supermassive. black holes. The one in the galaxy M87, it's an enormous black hole. It's about six and a half billion times a mass of the sun. And then at the same year in 2017, we got the data for Sagittarius A. Star, which is the black hole in the center of our galaxy.

It took a very long time to produce those images. But in 2018, I was part of one of the four imaging teams, which produced an image. And they locked us in a boiling hot room at Harvard in the middle of July. And we weren't allowed to talk with other people or anything. We just lived on a diet of takeaway food. and we actually produced the first images in about a week

and all the different teams met up at the end of the week and cross-compared and validated. There's a lot of work done afterwards, but we actually saw the first ever images in July 2018 and we had to wait until April 2019, so that was really hard. That's such a huge secret to just be sitting on. Yeah, it was. It was really like, wow, we know we've got something special here

and yet we have to keep stum. And how many people would have known about that image before it actually came out publicly. Yeah, that's a great question. I think at a time there were probably maybe around 200 of us total. Oh my gosh. The WhatsApp chat was just blowing it on lock.

And so how does it work? How are you actually able to take that image of a black hole? Yeah, so, you know, black holes are by definition almost black. They have an event horizon, that point beyond which nothing can escape, not even light. So they're very, very hard to image or to even. and to even resolve because they're very dim. You don't actually observe them. You observe the light from the matter

that's moving around them right at the edge of the event horizon. And they're also, even though these are enormous black holes, because they're so far away, their angular sizes on the sky are minuscule. They're around like 1, 190 millionth of a degree, if you will, on the sky. So in order to be able to resolve that, you need a very sensitive instrument, and you use radio waves to do this.

So we look at radio wavelengths, 1.3 millimeter wavelengths for what we used at the time. So you can actually see that on a ruler. And you take a picture by connecting radio telescopes around the world because you need an aperture size of around 10,000 kilometres to achieve the resolution required to take a picture. So you need the telescope as big as the Earth. You obviously can't build one that large.

So you have to connect them together using a technique called interferometry. Yeah. And I remember this story coming out and it was just so exciting. I think I was working on a five-life site. science show. And that first image on the camera, we were at our computers like, oh my God, have you seen this? So how just, you know, outside of that little office bubble that I was in, how important has this been for like the wider field? So that's a great question. I think there are sort of immediate consequences and there are consequences that we're beginning to appreciate more

and more now. I mean, first of all, it was a first. It was the first time humanity has ever seen a black hole or not actually the black hole but the light at the very edge of the black hole you see its shadow that's a first the first time ever in history that will be something that will even in the future thousands of years from now if we're still here and we deal with climate change and all of that and we can go and actually see these things in high res you know maybe with our own eyes perhaps we'll still look at the history books and that picture will be there so that was really cool but in terms of its implications you know this is actually we're resolving matter and radiation at the very edge of an event horizon.

An event horizon is where our notions of space and time start to break down. So you're actually looking into a regime where our fundamental understanding of the nature of reality is really in question. And we're starting to be able to probe that. So that I think is really cool that we're able to actually start answering some of these really deep and most existential questions. Yeah, this is the part of the podcast where those existential thoughts come into my head

And I'm like, no, don't go down that pathway. We have to keep talking about this. So what is next on that list of things to image? Are you even allowed to tell us? There's a lot that we can't talk about. Okay. More secrets. A colleague here in the audience, actually, from Taiwan,

who's in the project as well. So he's also checking to make sure that I don't say. I'll see you at the bar afterwards. I hung you. So what I can say is that, first of all, you know, at the moment, the technology is such a need. infrastructure is such that we can only really keep observing the two black holes that we've already seen, but we can do so with higher angular resolutions. That's the first thing.

There are a lot of plans to expand the array and push to much higher resolutions, which will enable us to be able to actually see what's going on closer to the event horizon. And in the case of, for example, M87, which is this very large black hole in this distant galaxy, how that's connected with relativistic jets and how they're powered. But, you know, there are proposals that we're all working on to put telescopes in orbit around the earth, which immediately extends your baseline length by a factor of five to ten, so your resolution improves concurrently. And then with that, actually, we'll be able to observe at least 10 to 15 other supermassive black hole sources. And there's really cool stuff we can do besides, because

you can actually improve your integration time, and you can actually have sequential images, i.e. a video. And in time, we may be able to actually see the dynamical properties, of black holes as they feed as well. Oh my God, that would be amazing. I think my tiny little mind would explode all over again. We are going to have more questions about that later, but I do want to put this question to you from Paul Winlaw in British Columbia, who says,

Dear lovely supermassivites, the Event Horizon Telescope gave us our first black hole images by merging the data from several telescopes around the world, in effect creating a virtual aperture about the diameter of Earth. What other objects and what more do you? detail might we be able to visualize if our virtual aperture was the diameter of the Earth's orbit. Go. Gosh. So, okay, in brief.

So if we had an aperture, there's one AU in size, goodness me. Well, first of all, putting aside technical feasibility, which is a concern, which we can touch on. That's fine. We'll get to that later. But we care about what we can do. So put that all this one side. The first thing is you'll be able to take pictures of black holes in their immediate

environments with just such exquisite angular resolution that you could pick up turbulent structure and you would be able to push to very high frequencies. So you're not limited by the absorption of Earth's atmosphere with ground-based telescopes. We'd be able to image a huge, huge sample of supermassive black holes in AGNs, you know, thousands, perhaps millions. And that's active galactic nuclei. Active galactic nuclei, that's right. So these are black holes in the centers of galaxy's supermassive black holes that are actively feeding and powering relativistic jets i mean it's really epic to be honest so great question and jim jim wild is here as well so jim you study the natural space environment like all infinity of that or it's not it's not quite

infinity and beyond um so when we talk about the space environment one of the things to think about is that the earth's environment doesn't just stop at the top of the atmosphere it's very easy to just think that we, you know, and we have these amazing images, the pale blue dot image, pointing out just how small we are in the blackness of space. But in reality, our environment of our planet is very closely linked to our nearest star and the other planets in our solar system. And so really, I'm a space plasma physicist, and I study the links between the sun, the Earth, and the sun and the other planets. And we are electromagneticly connected in the region of space we call the heliosphere. So this is the volume of

of space in which the sun dominates. So I'm a bit of a sort of myopic astronomer. Everything's quite up and close and personal compared to some of my colleagues on the panel here. So we're looking at they're really up-close stuff. But it's a really interesting and slightly different branch of astronomy insofar as most traditional forms of astronomy will rely solely on radiation emitted from an object

or reflected from an object, which you were able to detect at the Earth. More recently, we've been able to start looking at gravitation. waves in the fabric of space time and I'm already starting to get out of my comfort zone but those are we can probe what's on our coming towards us and that's through radiation. Space plasma physicists,

space environment scientists we're able to actually build things that will fly to and detect and smell and measure the things we're trying to do so these are in situ measurements so we can build spacecraft that orbit the earth and measure the particles the magnetic fields

the electric fields we can fly probes to distant planets we can put them on planetary surfaces and actually touch things so it's quite it's a slightly different way of doing things but then actually we can then combine those so those things you can do is you can point these telescopes that are primarily designed to look at very distant objects on stars and other and other objects and you can point them at the nearby planets and get some really amazing remotely sensed measurements you measure the radiation but then we're also able to fly things at the same time to those those targets. And so it involves some slightly different skills and actually starting to look a bit more like environmental science because we can repeat measurements again and again and start to get

averages and trends and seasons in there. So it's a really interesting, slightly different flavour of astronomy. Yeah. And I understand that it's taking you to the high parts of the Arctic. So can you explain that? What happened there? What were you doing there? Yeah, that's right. So people like me often have to consider our life choices because, so, proper astronomers who look at stars with telescopes go to places like the Canary Islands and Hawaii and Australia and Hawaii. Honestly, I recall with Becky and she's like, I'm just going to go here and I'm just going up there.

I'm like, I'll stay in my office in East London. They do tend to go to these places that are warmer and drier and space scientists like me. Often we're interested in that region of the Earth where we're most connected to the space environment. And that electromagnetically speaking is near the magnetic poles. which are not at but quite close to the northern and the southern geographic poles, which means whilst my colleagues are all off packing their factor 50 to Hawaii, I'm putting on multiple, multiple layers to go to the high Arctic,

especially because one of the things I do, often a dinner party answer to what do you do would be, well, I study the northern lights. So you need it to be dark, which in the high Arctic or in Antarctica means you have to go during the autumn and winter months. So it's usually quite cold as well, quite dark. and so it's a very different sort of a way of doing experimental science. But it takes you

to some fantastic places. You know, I've done some experimental work up on the Svalbard Archipelago on Spitzbergen. So you've got a town that has everything functional you'd expect. It's got a couple of bars and a couple of restaurants and a school and a supermarket. But it's the only supermarket I've been

in where you put your rifle in, before you take your trolley out, you put your lock your rifle in because you need a rifle because there's lots of polar bears so you have a rifle with you and I should just say because people often ask have you ever seen a polar bear and the answer is no and I'm very glad that's good yes because they are quite large and I'm you know I'm not a very good shot and I'd probably just annoy it so so but you know you're in a different world where you're going to work potentially on a skidoo with a rifle yeah

so it's quite different you know science isn't all just melting ice in a bucket in a lab it's pretty badass am I allowed to say badass yeah yeah I think you just did matter um And what would you say surprises you most about, like, studying space environment? It's that connection, the fact that our atmosphere couples us to the space marine, so I study the northern lights. And so what you're seeing in the northern lights is that connection. We're seeing particles from the environment around our planet that are being accelerated by electric and magnetic fields,

just like in a particle accelerator, just like at CERN, just it's just its mother nature doing her thing, and firing material into the upper atmosphere, which is glowing like the surface of an old-fashioned cathode ray TV screen in response to being bombarded by these subatomic particles from outer space. And so it's pretty amazing. You can sit there and watch these things, and the legends have grown up over thousands of years

as to what we're looking at. But actually the physics that's going on is very familiar. It's like a neon lamp or a particle accelerator. It's just it's wholly natural. It's amazing. I have to say, Jim, you know, having looked to feel, displays the Northern Lights for a lot of my life. I saw one feeble one about 30 years ago. And last year, how did we get

so lucky even from... Even I managed to see them. And I missed the first good one, but I saw the second good one, so that counts. Yeah, two in one year was pretty impressive. It was ridiculous. It was epic. The second one, it went on all night. I thought, I've got to go to bed now. This might not happen in my lifetime, but I still have to get some sleep. It's two in the morning. I've got to go to an RAS council next day. Can you believe it? Right. Shall we crack on with some questions, Robert, Helen Gislehurst has asked a question about stars. My question is, does the UV output differ between different classifications of stars? As a blue-eyed redhead,

would it be safer for me to be living on a planet orbiting a red giant maybe? The classic supermassive question there, Helen. Yeah. Well, I get a little redden by the sun as well. Underneath these grey locks is in fact a redhead trying to get out. And when I'm out running and I get red from being out of breath as well, admittedly. So this is of interest in a sense. So would relocating to say a surviving planet around a red giant star help? And the nearest one, the nearest one that's a bit like the sun turns out to be Gamma Gakrux, the third brightest star in the constellation of the Southern Cross. And I looked at this, this afternoon after receiving the question, it's sort of helpful and there's a lot of caveat. So the amount of UV, the proportion of

ultraviolet coming from the star, is indeed a lot lower compared with the sun, because it's red. So as you'd expect, that means there's less blue light and therefore the stuff beyond the blue end of the spectrum is also reduced. But the brightness, the overall luminosity of the star is a lot higher. So it depends on where you are. If you were as close to the earth where you'd have other issues, probably like the star might have swallowed the planet up and you might have to look at it. But we'll skip over that. But we'll skip over that. If you were far enough out in the habitable zone, I was working out it would be about seven times the size of the sun in the sky. The star is actually 73 times

the size of the sun. And then it would help a bit. Now, the downside is that planet is unlikely to have had time to form an atmosphere you could breathe or indeed to live on. So there is that minor downside. But all things considered, yeah, at the right distance, maybe it would help a bit. But I still suggest wearing sun cream is much. Yeah, I mean, every day. Always.

And Jim, the next question is from Hannah Jackson on a delayed train. Would it be possible for a solar flare to actually help our planet? Could this be the solution where we're? thing to make British trains actually run on time. Okay, so I think I know where this is coming from. So the background to this question, I think, is that there's been a bit of work done. I'm very pleased to say, led by some of the folks at Lancaster, looking at the effects of what we call space weather on railways.

So space weather is a catch-all phrase that we use for how solar activity can impact technology and society. So this isn't just around what creates the Northern Lights, which are these people. pretty lights in the night sky. This is like how can it affect things like satellites and other technologies. And folks might have heard of space weather and often people might say, well, if there's a really bad space weather event, it might affect our power grid. And there is some truth in that. So believe us not, there's a lot of work that goes into modeling and understanding and forecasting and mitigating the risk to our power grid. So how does this come

about? Well, when the sun is particularly active, eruptions of material from the sun can fly through space, hit the Earth's magnetic field, and compress it. And the magnetic disturbances at the Earth's surface cause fluctuations of magnetic field here at ground level and anything that's electrically conductive, such as a length of power line or the Earth's surface, can have electrical currents induced in it, a bit like a motor. We call these geomagnetically induced currents. And they can interfere with the regular operation of power grids. And so this is a reasonably well-known phenomenon.

and people have talked about it for quite a while now. But actually, they can induce electrical currents in long railway lines as well. And believe us or not, we use electrical currents flowing through the railway lines to control some signals. And we have done for many decades. And what's interesting is we're looking at how basically a solar event might cause the signals on the railways to misbehave. And the good news is that it would take really quite a substantial big solar event.

So this is unlikely. There might be rail operators who would quite like to blame running trains or people who were late to a meeting. Leaves on the tracks, slow the flares, yeah. That's it, that's it. So the flare, sorry, I was late for my meeting.

And actually, it's probably going to be the very large events. We kind of see, you know, a couple of times a century that we need to worry about this. But it's interesting to understand how it happens. But I was really pleased because when this story, when it broke, we had a press release from a large conference

where one of my colleagues, one of my students, Cameron, and from Lancastert University was presenting these findings. One of the tabloids did pick it up with the headline I wish I'd written, which was simply, Houston, we have a problem.

Which I'm so sad I never thought of that. But I thought that was a crowning achievement until later in that week. Our story was mocked on, have I got news for you? So that is my career highlight. I will never go any higher than that. Amazing. And I should say that we are actually going to do

an entire episode on the Carrington event 4th September. But we have time to take a question from the audience. Does anyone have a question that they want to ask the team? Yes, this lady over here. Hi. My name's Mel. My question is, white holes discuss.

Zeri. Do you? White holes discuss. Let's see. Can I just say we get so many questions about white holes, yeah. So I get a lot of questions about white holes. And the thing is, I think it's good to remember why they've been hypothesized. So first, we have no observational evidence for them whatsoever.

And can we just take it a step back? What is a white hole? What is a white hole? Well, before we get into... It's a proposal for a solution of the problem that black holes actually have a singularity behind the event horizon. Okay. And how do you get around that problem?

You have an infinity in nature and we don't like infinities. nature doesn't like infinities. If it's a white hole, then you can travel past the event horizon of a black hole through it and it actually is connected at the other end to a white hole and you come out at the other side. And so in a sense, like black holes swallow and white holes spew out. That's a sort of nice way of thinking about it. Okay. So that's why they've been sort of conjured up. So there are people like Carla Rovelli who've written lots of nice popular science outreach books about this. They're one possible way to deal with this problem of the singularity though and there are perhaps more plausible ways but i like the idea of it because

it's kind of almost like a wormhole right well this is so i have a question are we saying that this is essentially black holes taking in matter white house spewing it out so on the other side that you know yeah somewhere else in the universe who knows well that is what we're saying right who knows will it's a great question yeah thank you so much and robert Jim and Ziri, we will have more questions for you in just a moment. Okay, Robert, Steve in Montreal has a question about the three-body problem. Are you ready? Of course. I'd like to know, is it possible with precision to ever find a stable orbit? Could there be one with three close points and three far away points?

Yeah, Steve, this is not just a cult science fiction series, but also a classic problem in orbital mechanics or how we work out how planet stars, etc, all be each other. And if you have two bodies, it's nice and simple, you can get precise solutions, everything's neat. But with three, we always have to use approximations and modelling, and if you wonder why astronomers spend an enormous amount of time coding and running things on supercomputers, it is to get things like this done more precisely. And you basically become less certain about them as you go further into the future or look further. back into the past. And that's because the bodies in the system perturb each other a bit and it gets even more complicated in a real system because it won't just be three if you think about, say, the solar system with many, many bodies, you know, Earth, the Sun, but also Jupiter, the other gas giants, everything in it makes it complicated. So as a result, it becomes,

you can't say it's absolutely predictable. But a really good close example is even the moon going around the Earth, where because the influence of the sun, you know, if you were to run the clock forward. I think, I'm pretty sure that you can't go forward more than a few thousand years to predict eclipses, that there are other reasons for that to, let alone millions. But what you do know, and what's interesting, is that your models will tell you that those orbits are stable. So the answer to the question about, you know, can you find a stable orbit? Well, yes, the Earth has been going around the sun for a very long time. You know, four and a half billion years, it's in a stable orbit. And so, effectively, are the other planets? So we can say that with a great deal of confidence.

And we know that, you know, although there are things like procession where the kind of wobble of the Earth's orbit changes over time, the wobbly this axis and so on, the orbit itself is very, very, very stable. It has remained so for billions of years and will remain so for billions of years. I mean, there will be some very long-term effects like the mass of the sun drops a bit, then the Earth's orbit gets a bit further out. And if you had a very, very, very long time in the universe, then things like gravitational radiation and decay of orbits happen. But basically, you know, it's very stable. So, you know, we can be very confident about that, even though we can never quite solve it precisely. There's a lot of things in astronomy we don't solve precisely, by the way.

It's just a given. Okay, thanks, Robert. I'm Zeri. Will from Newcastle-upon-Tyne asks, if space and time flip after crossing the event horizon of a black hole, would that mean that you could theoretically travel through time inside a black hole the same way as you can travel through space outside of a black hole? Thanks.

It's amazing. Yeah, thanks to Will. I'm getting all the easy questions tonight. This is fantastic. I really like this question because, so when you cross that event horizon, right, you're trapped forever within the black hole, right? That is the threshold. You cross that event horizon, you're forever trapped.

Now, if you look at the mathematical theory of general relativity, the coordinates in space and time do indeed exchange places. But that doesn't mean that you suddenly start traveling in time. It means that a distant point that's in your future. And in this case, that's actually the singularity of the black hole. Instead of it being a place in space that you could or could not end up at, it becomes a place in time. And for us, time only moves forwards, right?

And so it means that you will inevitably end up at that singularity once you cross the event horizon. So that's what it really means by the space and time coordinate that's changing around. So basically, if you cross the event horizon, The singularity is in your future. You can't avoid it. You're doomed. Sorry. Okay.

And Jim, Harry Lampert, who used to study at Durham, asks, how can a planet, Mars, with basically zero atmosphere, have storms that are powerful enough to cover the entire planet? And why don't we have the same ones on Earth? It makes Mars sound like a really boring place to be, isn't it?

Zero atmosphere. It's like not good to have a party on Mars. So there's a few things. things at play here. So the gravity on Mars is much less than on Earth, so about one third of the Earth's gravity at the surface. And although we say there's basically zero atmosphere, there is actually an atmosphere, there is wind. It's just, it's a very thin atmosphere. See my earlier answer about connections to the sun. The sun has stripped away most of Mars's atmosphere because it doesn't have a strong magnetic field to provide a force field. The shield's the

atmosphere. So most of the atmosphere is stripped away, but there is still an atmosphere. It's not breathable. It's mainly carbon dioxide. But what happens with dust on Mars is any dust that is picked up by the atmosphere, because the gravity is so very low, it actually stays airborne for quite a long time, and it can be lofted up into the atmosphere a long way. And of course, Mars is all dust. It's basically a desert. It's an arid, cold desert. There's no precipitation. So this system can just build and build, and dust can get picked up, pulled up into the upper atmosphere. And then it's dark, it's that red color, it absorbs heat. So actually, heat starts to warm up the dust and it can loft it more and you can get

temperature gradients and you get these big storms that envelop the whole planet. Interesting, though, because the air is so thin on Mars, actually, even though it can move very fast, much faster than on Earth, it doesn't have much force behind it. There's not much mass to it. And so when you do see some of these, the famous film The Martian, based on the book by Andy Weir, it prides itself on being a really scientifically accurate piece of science fiction. But those opening scenes where Matt Damon is blown off his feet by a piece of kit being blown by a storm probably wouldn't happen because even in a very fast-moving wind,

there's not enough mass in the atmosphere to blow you over. So that takes care of Mars, but why don't we get these on Earth? Well, on Earth, of course, only about one-third of the Earth's surface is covered in desert. And then a lot of the rest of it is oceans and forests and things. so there's less area where dust can be picked up from but we all know you know you wash your car that's a good good way of bringing saharan dust to your driveways it all just gets dumped on you it gets dumped on your car because precipitation is pulling out the atmosphere rain is pulling it out of course there's no rain on mars so so on the earth surface gravity is stronger it's pulling the dust back down we've got less of the surface of the planet covered in dust have got more oceans and things we've got precipitation to just clean out the atmosphere so the planetary processes are just a bit different because our planets have just evolved differently, probably from quite similar origins. Yeah. Amazing. Thank you. Who from the audience has a question? Anyone right here at the front? Hello, I'm Hugh Stewart. I'm interested in a big solar flare. You've talked about

it affecting railways and power lines. Could it affect the internet, GPS, financial systems, for microelectronics, if you like? Yeah, so that's a really good question. And to lesser or greater extent the answer is yes. So the very sensitive microelectronics can be influenced by what we call single event upsets. So subatomic, high-energy subatomic particles such as cosmic rays or particles from a solar energetic particle event. So these are usually particulate. So high-energy particles moving at near the speed of light rather than a solar flare, which is radiation. But these bursts of particles can make it down to ground level even. So electronics in orbit in spacecraft, potentially on aircraft,

but also potentially at ground level, could be impacted by very large events. So usually most systems have sort of a jury of computers that will talk to each other. So if just one of them goes a little bit crazy for a moment because of basically some electronic charge being dumped in a silicon chip, flipping a binary number from a zero to a one, normally that's not a problem, but perhaps if that's turning off autopilot on your plane or thing. You normally have several computers and that would need to happen several at once. So we can engineer around these, but yes, it is a problem for satellites and for avionics and on the ground.

So as we get more and more dependent on these things, there's a much bigger drive to understand forecast and mitigate. And believe it or not, severe space weather is on the UK government's national risk register alongside droughts, heat waves, pandemic viruses, tsunamis, wakes volcanoes. It's in there. Severe space weather. I've often wanted Jim, actually, you know, those single events. Is that why my laptop crashes sometimes? Is it the excuse we're going to get for the operations? I feel like this entire idea. The excuse is like, it's a solar flare. You could try that at the Apple Genius Bar, and I'm sure the brands are available

and see if they pick it for you. But it could be worth a try. Amazing. And so, Robert, we have a question here from Sasha Mintz. And she asked, Please explain stars. Is the edge slash surface of a star a defined diameter or fuzzy? That's actually a great question, Sasha. And I like it because I think about it every so often. If you look at the sun, you think, well, you're seeing what looks like the surface of it.

And of course the answer is you're quite right. It is a bit fuzzy. It's got layers of plasma all the way down to the core plasma electrically ionized gas where the fusion reaction happens are happening and then it's gas is all the way up. But it goes beyond what you easily see. So when you see that classic disc, now, my health warning is obviously don't stare at the sun, right? You know, use the safe telescope, use a safe filter, all of those things you get right first. But if you do that, you tend to be looking at, depending on the color of the filter,

as sort of quite often a yellowish-oranges disc and sunspots and so on, the things people want to see. And that's the bit you would think of as the surface, but it's the what's called the photosphere, where about 99% of the light is coming from. And so that's why we think of it as that. But of course, it's not a solid surface. It extends well beyond that. you've got the outer atmosphere, the corona, you can even argue, perhaps a bit dubiously, but the sun's influence is so great, you know, could we argue the sun basically fills the solar

system, the solar wind streams out into space? So the answer to the question is, it is indeed fuzzy. Amazing. And Ziri, Chris O'Hare asks, my question is, why does everyone seem to say that we see supermassive black holes in most, or almost every, or the majority of galaxy? rather than all galaxies. Now, that is a fascinating question, actually. There's a lot of subtleties to that, so I'm going to do my best and keep this brief, right? We do mean most, but not all.

There are actually some special cases which we think are exceptions. So most galaxies we expect to have a supermassive black hole because we see, for example, massive relativistic jets, so something has to power them. But there could be scenarios where the galaxy no longer has a supermassive black hole at its core. So one scenario could be two galaxies merging.

So the two supermassive black holes would merge. You'd end up with one final supermassive black hole. But because the angular momentum is at a weird angle with respect to the galaxy itself, it can kick itself out of the galaxy. And then you'd have a galaxy without a central supermassive black hole and a rogue supermassive black hole

moving through the cosmos, which is terrifying. But it can actually happen, and this has been shown with simulations quite accurately. So they must at least exist. universe is a big place. And so we're saying those spirals are spiral galaxies, potentially ones with supermassive black holes? Ah, so that's a great question, Izzy.

So the spiral galaxies, like our own galaxy, are actually quite young galaxies. Okay. So it's actually the other way around. So it might be the galaxies like our own, which are young, haven't undergone like mergers yet. Okay. But much older galaxies, like elliptical-type galaxies,

they, we call them like sort of red galaxies. there's a lot of evidence to suggest that many of them have had mergers in the past few hundred million years or so and we don't have the capacity yet to study this but in time with gravitational waves we'll be able to see if it is a binary black hole or not

and we might even be able to resolve them with instruments like the Event Horizon Telescope and actually see if there are two black holes or not I mean you need to make this happen like five minutes go like come on let's go definitely do we have any more questions from the audience here yes right

up over the front, thank you. So you was talking about like space weather and solar winds and stuff. And I was wondering, does that affect the planets that are further out than us? Like, can you get northern lights and Jupiter's Saturn? Or is it just where close enough that they can reach us? Ah, short answer. Yes.

So you get very powerful northern lights and southern lights on Jupiter and Saturn. They're a little bit different to the Earth because the magnetic fields are of different intensity. So Jupiter, for example, has the most powerful, apart from the sun, has the most powerful magnetic field in the solar system.

In fact, if you could see magnetic fields with your naked eye, Jupiter's magnetic field would make it appear to be the size of the sun viewed from Earth, even though it's five times further away. So it's enormous. And basically there's a huge amount of plasma being created in the Jovian magnetosphere because the volcanic moon I-O is spewing out sulfur and sulfur dioxide, which gets irradiated by sunlight. And then that gets broken down as the electric-charged particles,

which suddenly feel the effects of the magnetic fields of Jupiter, and they then rain down into Jupiter's upper atmosphere. And so Jupiter's atmosphere glows in ultraviolet and x-ray lights. You get these northern lights and southern lights on Jupiter. And yeah, so we look around the solar system, where we see magnetic fields and atmospheres, we start seeing northern lights. And I like to think when we start looking out into distant parts of the universe,

as a simple earth-focused person or a planetary-focused person, I like to think that, well, perhaps one day we'll be measured, measuring the photons of light from Aurora on other planets that are telling us that those planets have a magnetic field and an atmosphere. And probably magnetic fields are required to give a planet enough shielding to sustain an atmosphere. The reason Earth's got an atmosphere and Mars hasn't is Mars and magnetic field died away. So there are even some folks who will argue that Aurora are really closely related to habitable environments for life. And, you know, that could be a way of looking for habitable environments, looking for auroral emissions out there. in the universe. So it's a really universal

phenomenon. Great question. That's a really great question. And it leads me on to another one which is do we now need to add that our magnetic field will die away to the list of things we need to worry about? Oh, there's such a long list. It depends how close one is to write in a ground application. So

the Earth's magnetic field does vary over time. And we know from experimental measurements, we can see that the polarity of the Earth's field has flipped. Typically, several times, or many times every million years or so. We can see it in seafloor spreading. We can see the polarity of the magnetic field stored in the rocks

where seafloor is being created, and it's stripy. You can see it's one orientation for a few hundred thousand years, then it flips the other orientation, it flips back. And we don't really know does it flip quickly? It probably isn't overnight, but geological timescales, is it quick hundreds of years or thousands of years? Or does it take much longer? What we do know, though, is that throughout life on Earth,

this has happened many times. So clearly when the Earth's magnetic field is switching its polarity, it's not like the Earth gets sterilised by space weather and everything dies. However, last time it happened, we didn't have power grids, railway lines, satellites and everything else. So it will be interesting to see what happens. We're slightly overdue. Interesting, yes, yes, it will be interesting, that's one way of put to it. It will be a good time for space weather researchers, and we are slightly overdue in geological terms.

so we wait with interest. Well, yes, I suppose so. Numerous bad science fiction films on the way. There were several already. I actually have a great talk I do for people on bad science fiction like that, and it is, yeah, there are some absolute caucus. Okay, producer Richard, that's another episode that we need to revisit. Do we have any more audience questions?

Hi, thanks. I was just wondering if you'd thought of using the Event Horizon Telescope to look for or look at black holes in sort of local dwarf galaxies or if that's even possible? So that's a great question because we are, we, you know, we're limited to just two sources right now. The difficulty is just the angular size, right? And in the local dwarf galaxies, you'd expect the black holes. If intermediate mass black holes exist, then they, they wouldn't be any larger than those. And those already actually are at least two orders of magnitude,

Factor of 100, smaller in angular size than we could achieve even with telescopes in orbit. So we might even need to put telescopes further out in the solar system before we could resolve stuff like that. And then, so I'm guessing you're a professional scientist with that question. So if I can just give a little bit more detail, if I'm allowed to. You're allowed to, I won't allow it, yes. I'll explain. I'll explain, is that there is a lot of contamination along the line of sight, right? So that radiation that's produced by the matter at the edge of the event horizon of those black holes

is attenuated by the intervening material and the kind of regions that you're talking about are quite tricky. There's a lot of dust, there's a lot of refraction and diffraction and so on. These are all things that you'd also have to mitigate in order to get a coherent signal. So it's a great question. It's very hard for many reasons, but it could be in the next 50 years that we're able to actually perform those kinds of measurements.

Amazing. Thank you. And we've got any more questions, anything that you want to ask our entire panel? Otherwise, I have a question. What do you think could be the greatest advance in our understanding and studying of supermassive black holes?

What could be the greatest advance in our understanding through studying supermassive black holes? Gosh. So many things. So if I were to just pick one or two, that's a really good question. I can see the cogs one. Yeah, the little hamster is running around on the wheel as we speak.

Well, it's a supermassive. Indeed. It's not supermassive for a reason. So I would argue, this is perhaps my own personal feeling here, that supermassive black holes change on timescales slowly enough because they're so large that you can actually disentangle different physical processes that are happening around them. So if the black hole is, let's say, a billion times the mass of the sun, it takes several weeks to orbit it, which gives us.

enough time to be able to take a picture of the plasma as it's moving around. They also tend to power relativistic jets and we see them everywhere in the universe. They're actually incredibly powerful events. They're highly collimated beams of plasma. If any of you have watched anime, you'll see like Kamehamehars from Dragon Ball Z. So there's a, there's a reference there. But it's huge amounts of energy and material are launched into the intergalactic medium and you know understanding this is is that the nexus of gravitational physics quantum field theory fundamental particle physics and what lies beyond the standard model and I think because supermassive black holes are large enough that they change

slowly enough we can disentangle all these different processes and actually study them and then they make for wonderful laboratories to test physical theories that you know because we simply can't mimic those conditions here on earth we can't build extreme gravitational fields. We can't generate magnetic fields of the, you know, thousands to millions, billions of gauss. We can't have those kinds of densities and temperatures that are billions of Kelvin. So, yeah, that's a great question to end on. Brilliant question. Thank you so much. And I think that's almost it for today. But can we end the show with some stargazing for this month? Robert, what can we see in the night sky?

Yeah, I mean, I personally love looking at the sky in September because it's not too cold. you know, the nights are a bit longer. The summer Milky Way is really good. You know, you think of it as being in the middle of it. Actually, of course, in June, July, the nights aren't very dark. So the autumn's a really good time to see it. And it runs up through one side of the summer triangle through the constellations of Cygnus and Aquila.

A really, really stunning sight. Get yourself somewhere dark to see that. And a bit later on, you'll see things like the autumn constellations, the square of Pegasus come into view. Now, planet-wise, this month is pretty good. You've got Saturn and it's best on the 21st September. Becky will be pleased. as the Saturn obsessive on the show.

The little Saturn alarm will be whirring as we. Absolutely will. Even the rings are opening up. You know, the horrible disappearance of the rings is coming to an end. So, you know, they'll be opening up over the next few years. And you just need to look down in the southern sky later in the night. It'll be an obvious bright yellow dot to the eye. And if you've got a small telescope, you can see the rings fairly easily.

Jupta, though, is not visible to the small hours. And Venus is really a sort of pre-dawn object. You need to be up about 4 a.m. Although if you do happen to be up there, it is really unmistakable over in the east. And the moon this month, though, is doing a couple of nice things. So it's got some fairly special displays. So on the 12th of September, it'll move in front of the Pleiades cluster, which is a really nice photogenic opportunity,

and visually good as well. If you've got a pair of binoculars, what's called just a waning gibbous moon, so beyond fall, but it'll be there. It'll look good. You'll see craters and all that, and you'll see this lovely cluster of stars around it. And it's a good thing to try and photograph as well. And on 7th of September, the moon's actually going to rise at sunset

in a total lunar eclipse, which is visible from the UK, but will be fairly low on the horizon. So it'll be a kind of competition. It's moving actually when we see it out of the earth's shadow, and the sky will be getting darker, but the moon will be there. And if it gets dark quickly enough, and we know how it would get dark, but it'll be that competition, this reddish moon hanging in the darkening sky. So potentially a really beautiful sight, actually. You need a very good level horizon.

It's only a few degrees above the horizon. But again, I do recommend trying to see that and take some pictures. pictures. And these are really great, you know, smartphone opportunities, I think. The nice thing is that the tech that you need to capture these things is now so simple. You can share them with us on our social media accounts. You know, we put those or in the supermassive club that Izzy's going to mention. Absolutely, yes. I'm always on the Supermassive Club just looking at what people have posted in our Stargazing Forum. I love it. And of course, we're still in a period when the sun is nicely active. So I keep thinking my neighbours where I live, keep asking me, is there going to be

another display of the Northern Lights, and the answer is, I guess, if we wait long enough, how good it is, you just never know. But certainly the further north you are in the UK, obviously you get more chances. So in a place like Durham, you've got more chance than I have in Sussex. But you just never know. You have to keep an eye on. There's a brilliant app run by, I think it's run by Lancaster, isn't it? The Aurora chat. Yeah. And notices I'd pick the microphone up ready to jump. Yeah, it did. Aurora Watch. Download it. Only set it to red, though, because if you live where I do, otherwise, you get alarms at three in the morning for something only people in Shetland

can see. That's my tip. You know, just, you don't want to, and your partners and family do not appreciate the alarm at odd hours. I have been told. It is brilliant. I love it. And I think that's it for this month and that's the end of our summer live shows and we'll be back next

month celebrating the Carrington event. This is the burst from the sun that set the Victorian internet on fire. And as ever, please keep sending your questions to podcast at r-r-as.ac. Find us on Instagram at Supermassive Pod. You can join the Supermassive Club. We're everywhere.

And I just want to say a huge thank you to everyone here at the National Astronomy Meeting in Durham for coming along. Until next time, happy stargazing. Yay. Thank you.